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A.M. Scheuhammer
S.L. Money
D.A. Kirk
G. Donaldson
Lead fishing sinkers and
jigs in Canada: Review of
their use patterns and
toxic impacts on wildlife
Occasional Paper
Number 108
Canadian Wildlife Service
Envi ron ment Environnement
Canada Canada
Canadian Wildlife Service canadien
Service de la faune
Canadian Wildlife Service
Occasional Papers
Occasional Papers report the peer-reviewed results of original
research carried out by members of the Canadian Wildlife
Service or supported by the Canadian Wildlife Service.
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University of Western Ontario
David Cairns
Fisheries and Oceans Canada
Fred Cooke
Simon Fraser University
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University of New Brunswick
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U.S. Geological Survey
Raymond McNeill
Université de Montréal
Ross J. Norstrom
Canadian Wildlife Service
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Canadian Wildlife Service
Harold Welch
Northwater Consultants
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Canadian Wildlife Service
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Canadian Wildlife Service
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Canadian Wildlife Service
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http://www.cws-scf.ec.gc.ca
A.M. Scheuhammer1
S.L. Money1
D.A. Kirk2
G. Donaldson3
Lead fishing sinkers and jigs in
Canada: Review of their use
patterns and toxic impacts on
wildlife
Occasional Paper
Number 108
Canadian Wildlife Service
March 2003
1Canadian Wildlife Service, National Wildlife Research
Centre, Carleton Uni ver sity, Raven Road, Ottawa ON
K1A 0H3
2Aquila Applied Ecol o gists, Box 87, Carlsbad Springs, ON
K0A 1K0.
3Chelsea Creek Con sulting, 694 Shefford Ct., Glou ces ter,
ON K1J 6X3.
A member of the Envi ron men tal Con ser va tion family
Également disponible en français sous le titre
Les pesées et les turluttes de plomb au Canada : Examen de
leur uti li sa tion et de leurs effets toxiques sur les espèces
sauvages
Service canadien de la faune, Pub li ca tion hors série n° 108.
Cover image adapted from a design concept by the CWS
Ontario Region
© Her Majesty the Queen in Right of Canada, represented by
the Minister of Environment, 2003.
All rights reserved.
Catalogue No. CW69-1/108E
ISBN 0-662-33377-2
ISSN 0576-6370
National Library of Canada cataloguing in
publication data
Main entry under title:
Lead fishing sinkers and jigs in Canada: review of their use
patterns and toxic impacts on wildlife
(Occasional paper, ISSN 0576-6370; no. 108.
Issued also in French under title: Les pesées et les turluttes
de plomb au Canada.
Includes bibliographical references.
ISBN 0-662-33377-2
Cat. no. CW69-1/108E
1. Lead – Environmental aspects – Canada.
2. Fishing weights – Environmental aspects – Canada.
3. Fishing tackle – Environmental aspects – Canada.
4. Fishing – Equipment and supplies – Environmental
aspects – Canada.
I. Scheuhammer, Anton Michael, 1952-
II. Canadian Wildlife Service.
III. Series: Occasional paper (Canadian Wildlife Service);
no. 108.
TD196.L4L42 2003 363.17’91 C2003-980022-9
2March 2003
Abstract
More than 5 million Canadians take part in rec re -
ational angling each year, spending over 50 million days
fishing on open water. Rec re ational anglers con trib ute to
envi ron men tal lead depo si tion through the loss of lead
fishing sinkers and jigs. East year lost or discarded fishing
sinkers and jigs amounting to an estimated 500 tonnes of
lead, and rep re sent ing up to 14% of all nonrecoverable lead
releases in Canada, are deposited in the Canadian envi ron -
ment. Wildlife, primarily piscivorous birds and other water -
birds, ingest fishing sinkers and jigs during feeding, when
they either mistake the sinkers and jigs for food items or grit
or consume lost bait fish with the line and weight still
attached. Lead fishing weights that weigh less than 50 g and
are smaller than 2 cm in any dimension are generally the size
found to be ingested by wildlife. Ingestion of a single lead
sinker or lead-headed jig, rep re sent ing up to several grams of
lead, is suf fi cient to expose a loon or other bird to a lethal
dose of lead. Lead sinker and jig ingestion has been doc u -
mented in 10 different wildlife species in Canada. In the
United States, ingestion of lead sinkers and jigs by 23
species of wildlife, including loons, swans, other waterfowl,
cranes, pelicans, and cor mo rants, has been doc u mented.
Evidence gathered to date indicates that lead sinker and jig
ingestion is the only sig nif i cant source of elevated lead
exposure and lead toxicity for Common Loons Gavia immer
and the single most important cause of death reported for
adult Common Loons in eastern Canada and the United
States, fre quently exceeding deaths asso ci ated with entan gle -
ment in fishing gear, trauma, disease, and other causes of
mortality.
Except for a few local or regional instances, available
data indicate that Common Loon pop u la tions are stable or
increas ing through most of their Canadian range. There is
currently insuf fi cient infor ma tion to answer the question of
whether mortality through lead sinker poisoning may be
having pop u la tion-level effects on loons anywhere in Canada
or to estimate with con fi dence the minimum frequency of
poisoning that, combined with the effects of other envi ron -
men tal stressors, would be required to sig nif i cantly affect
pop u la tion dynamics. The most critical areas of new
knowledge that are required to enable confident estimates of
the pop u la tion effects of lead sinker poisoning in loons are
accurate life history data using indi vid u ally marked birds to
derive important pop u la tion param e ters for local or regional
loon pop u la tions in Canada; DNA analyses to better define
“pop u la tions”; a better under stand ing of the inter ac tions of
multiple envi ron men tal stressors that may influence pop u la -
tion dynamics; and incor po ra tion of these multiple stressors
into a large-scale spatial analysis using geo graphic infor ma -
tion systems. Such research would be expensive and
time-consuming, requiring long-term mon i tor ing of sub stan -
tial numbers of banded indi vid u als from several selected
pop u la tions.
There are numerous viable alter na tive materials for
producing fishing sinkers and jigs, including tin, steel,
bismuth, tungsten, rubber, ceramic, and clay. Tin, steel, and
bismuth sinkers and bismuth jigs are the most common com -
mer cially available alter na tives in Canada. Many of the
available alter na tive products are currently more expensive
than lead; however, switching to these products is antic i pated
to increase the average angler’s total yearly expenses by less
than 1% (~$2.00). Nev er the less, the continued avail abil ity of
(cheaper) lead products has made it difficult for the man u fac -
ture and sale of nontoxic alter na tives to achieve com mer cial
viability.
Some limited reg u la tory actions have been taken to
reduce the use of lead sinkers and jigs both in Canada and
elsewhere. In 1987, Britain banned the use of lead fishing
sinkers weighing less than 28.35 g. The United States has
banned the use of lead sinkers and jigs in three National
Wildlife Refuges and in Yel low stone National Park and is
currently con sid er ing further action. New Hampshire, Maine,
and New York have ratified statewide reg u la tions pro hib it ing
the use of lead sinkers beginning in 2000, 2002, and 2004,
respec tively. Envi ron ment Canada and Parks Canada pro hib -
ited the pos ses sion of lead fishing sinkers or lead jigs
weighing less than 50 g by anglers fishing in National
Wildlife Areas and National Parks under the Canada Wildlife
Act and the National Parks Act, respec tively, in 1997.
However, these latter two reg u la tions are of limited geo -
graphic scope, covering <3% of Canada’s land mass, and
they affect only about 50 000 (<1%) of the estimated 5.5
million rec re ational anglers in Canada. Currently, the
majority of rec re ational anglers continue to use lead sinkers
and jigs.
3
Acknowl edge ments
The authors would like to thank the following: I.
Storm, for creating several of the geo graphic infor ma tion
system maps used in the report; K. Marshall, B. Braune, C.
Hebert, and A. Gaston (Canadian Wildlife Service [CWS],
National Wildlife Research Centre), R. Milko and E. Reed
(CWS – Head quar ters), D. McNicol and R. Weeber (CWS –
Ontario Region), N. Burgess (CWS – Atlantic Region), D.
Evers (BioDiversity Research Institute), V. Thomas (Guelph
Uni ver sity), and M. Pokras (Tufts Uni ver sity), for reviewing
various drafts of the manu script; A. Erskine and J. Kerekes
(CWS – Atlantic Region), D. Bordage (CWS – Quebec
Region), K. Ross (CWS – Ontario Region), J. Hines (CWS –
Prairie and Northern Region), A. Breault (CWS – Pacific and
Yukon Region), B. Koonz (Manitoba Depart ment of Natural
Resources), and A. Brazda (U.S. Fish and Wildlife Service),
for providing infor ma tion on Common Loon numbers in
various parts of Canada; M. Wayland (CWS – Prairie and
Northern Region), L. Champoux and J. Rodrigue (CWS –
Quebec Region), D. Campbell (Ontario Vet er i nary College),
and P.-Y. Daoust (Atlantic Vet er i nary College), for
providing us with unpub lished data on wildlife mortality
from sinker ingestion; rep re sen ta tives of private wildlife
reha bil i ta tion centres, espe cially K. Chubb (Avian Care and
Research Foun da tion) and H. Pittel (Avicare Reha bil i ta tion
Centre), for allowing us to use their orga ni za tions’ unpub -
lished data; and Sta tis tics Canada, for providing us with the
sinker import data.
This pub li ca tion was produced by the Sci en tific and
Technical Documents Division of the Canadian Wildlife
Service. The following people were respon si ble:
Michèle Poirier — coor di na tion and super vi sion;
Sylvie Larose — layout; Marla Sheffer (contract editor) —
sci en tific editing; and Mark Hickson — printing.
4
Ta ble of Contents
In tro duc tion 7
1. Rec re ational an gling in Can ada 8
1.1 Es ti mating the num ber of rec re ational
an glers in Can ada 8
1.2 Geo graphic dis tri bu tion of rec re ational
an glers in Can ada 8
1.3 An gling pres sure in Can ada and the
United States 8
1.3.1 Can ada 8
1.3.2 United States 9
1.4 Sum mary 9
2. Es ti mating the mag ni tude of lead sinker and
jig use 12
2.1 Mar ket de mand 12
2.2 Im port of lead fish ing sink ers and jigs 12
2.3 Do mes tic pro duc tion of lead fish ing
sink ers and jigs 13
2.4 Es ti mating en vi ron men tal lead de po si tion
from the an nual loss of sink ers and jigs 14
2.5 Sum mary 16
3. Lead sinker in ges tion and poi son ing in wild life 17
3.1 Lead poi son ing in wild life 17
3.2 Lead sinker and jig in ges tion cases in
wild life 17
3.3 Types and sizes of lead fish ing weight
in gested by wild life 20
3.4 Rel a tive im por tance of lead sinker
in ges tion as a cause of Com mon Loon
mor tal ity 20
3.5 Sinker in ges tion by wild life — Spa tial
dis tri bu tion 22
3.6 Sinker in ges tion by wild life — Tem po ral
trends 22
3.6.1 An nual trends 22
3.6.2 Sea sonal trends 22
3.7 An gling pres sure and the in ci dence of
sinker in ges tion in wild life 22
3.8 Sum mary 22
4. Can pop u la tion-level ef fects of lead sinker
poi son ing be de ter mined for Com mon Loons
in Can ada? 26
4.1 Back ground 26
4.2 Spa tial pat terns of abun dance 27
4.3 Pop u la tion trends 29
4.4 Pop u la tion mod el ling 32
4.5 Matching the spa tial dis tri bu tion of
loons with geo graph ical pat terns of
an gling pres sure — us ing GIS to model
re gional ef fects 35
4.6 Sum mary and pri or i ties for fu ture re search 36
5. Ini tia tives to re duce the im pacts of lead
sink ers and jigs on wild life and the en vi ron ment 37
5.1 De vel op ment of lead-free fish ing sink ers
and jigs 37
5.2 Reg u la tory and aware ness ini tia tives
in Can ada 37
5.3 Reg u la tory and aware ness ini tia tives
in other coun tries 39
5.4 Sum mary 40
Lit er a ture cited 41
List of ta bles
Ta ble 1. Rec re ational an glers in Can ada 9
Ta ble 2. Studies re port ing den si ties of lost or
dis carded sink ers 15
Ta ble 3. Sum mary of tis sue lead con cen tra tions
for Com mon Loons with and with out the
pres ence of lead ar ti facts in their di ges tive sys tems 18
Ta ble 4. Wild life spe cies doc u mented to have
in gested lead fish ing sink ers or jigs in Can ada,
1964–1999 18
Ta ble 5. Wild life spe cies doc u mented to have
in gested lead fish ing sink ers or jigs in the United
States, 1976–1999 19
Ta ble 6. Per cent age of to tal re ported mor tal ity
in adult Com mon Loons at trib uted to lead
sinker/jig in ges tion in Ca na dian and U.S. stud ies 21
5
Ta ble 7. An gling ef fort in ar eas of North Amer ica
where sinker/jig in ges tion has been re ported in
Com mon Loons and other wild life 24
Ta ble 8. Es ti mated num ber of Com mon Loon
ter ri to rial pairs and in di vid u als in Can ada 27
Ta ble 9. Pop u la tion trends in dif fer ent Ca na dian
ecozones de rived from the Breeding Bird Sur vey 32
Ta ble 10. Man u fac turers of nonlead fish ing weights 38
Ta ble 11. Es ti mated con sumer costs as so ci ated with
the use of lead and al ter na tive sinker prod ucts for
sport fish ing in Can adaa38
List of fig ures
Fig ure 1. Pro por tion of the to tal num ber of open
wa ter rec re ational an gling days spent within var i ous
re gions of Can ada 9
Fig ure 2. Es ti mated av er age an nual an gling ef fort
per in di vid ual an gler, by prov ince and na tion ally 9
Fig ure 3. Es ti mated rec re ational an gling pres sure
in var i ous re gions of On tario in 1991 10
Fig ure 4. Rec re ational an gling pres sure by prov ince
in Can ada and by state in the United States 10
Fig ure 5. Es ti mated break down of the av er age
Ca na dian an gler’s an nual bud get of ap prox i mately
$600 13
Fig ure 6. Es ti mated cur rent pro por tional use of
lead ver sus nonlead sink ers and jigs in Can ada 13
Fig ure 7. Es ti mated an nual weight of sink ers
im ported into Can ada from ma jor geo graph ical
re gions 13
Fig ure 8. Pro por tions of to tal sinker im ports
(1988–1998) from var i ous world re gions 13
Fig ure 9. Sources of lead fish ing tackle com pris ing
the Ca na dian fish ing sinker mar ket, 1995–1998 14
Fig ure 10. Sources of lead fish ing tackle com pris ing
the U.S. fish ing sinker mar ket, based on 1994
es ti mates 14
Fig ure 11. Es ti mated en vi ron men tal lead re leases
in Can ada from rec re ational an gling and other
sources 15
Fig ure 12. Rel a tive im por tance of dif fer ent causes
of adult Com mon Loon mor tal ity in New Eng land
be tween 1989 and 1992 (n = 60) 21
Fig ure 13. Rel a tive im por tance of dif fer ent causes
of adult Com mon Loon mor tal ity in Can ada 21
Fig ure 14. Dis tri bu tion of re ported in ci dents of
wild life mor tal ity as so ci ated with lead fish ing
sinker and jig in ges tion in Can ada and the United
States. Num bers of dif fer ent spe cies per prov ince
or state are also in di cated. 23
Fig ure 15. Rec re ational an gling pres sure in Can ada
and the United States, with an in di ca tion of those
prov inces and states where wild life mor tal ity from
lead sinker or jig in ges tion has been re ported 23
Fig ure 16. Re gions of east ern Can ada and the
United States with high rec re ational an gling pres sure,
over lain with lo ca tions of known in ci dents of
Com mon Loon mor tal ity from in ges tion of lead
fish ing sink ers or jigs 24
Fig ure 17. Per cent age of Ca na dian Com mon Loon
pop u la tion in dif fer ent prov inces/ter ri to ries 28
Fig ure 18. Geo graph ical dis tri bu tion and rel a tive
abun dance of Com mon Loons dur ing sum mer,
1982–1996, based on Breeding Bird Sur vey data 29
Fig ure 19. Win ter dis tri bu tion and abun dance of
Com mon Loons in North Amer ica, es ti mated
through the Christ mas Bird Count 30
Fig ure 20. Counts of Com mon Loons in Que bec,
1990–2000, dur ing Black Duck Joint Ven ture
he li cop ter sur veys 30
Fig ure 21. Es ti mated Com mon Loon pop u la tion
trends in east ern Can ada, from an nual sur veys of
in di cated breed ing pairs 31
Fig ure 22. Trends in Com mon Loon num bers
es ti mated from Breeding Bird Sur vey data 32
Fig ure 23. Pop u la tion growth rate ver sus
re pro duc tive suc cess in Com mon Loons in New
Hamp shire 33
Fig ure 24. Pre dicted changes in the pro por tion of
hab i tat suit able across east ern Can ada for nest ing
piscivorous birds be tween 1982 and 2010, af ter
cur rent sul phate emis sion con trol tar gets are achieved 35
6
Intro duc tion
Rec re ational anglers use various sizes and shapes of
lead sinkers and jigs to sink hooks, lures, or bait while
fishing. Ingestion of lost sinkers and jigs occurs during
feeding, when water birds mistake them for food items such
as seeds or shelled inver te brates such as small snails or
clams. Fish-eating wildlife, par tic u larly loons, most often
ingest lead sinkers when they consume lost bait fish with the
hook, line, and sinker still attached.
Ingestion of small lead fishing weights has resulted in
the lead poisoning and death of water birds in Britain, the
United States, and Canada. Evidence presented in a previous
assess ment (Scheuhammer and Norris 1995) indicated that
the use of small lead fishing sinkers and jigs presented a risk
of toxicity and mortality for Common Loons Gavia immer,
par tic u larly in areas of intense fresh wa ter sport angling.
In response to the evidence presented in
Scheuhammer and Norris (1995), Envi ron ment Canada, in
part ner ship with Parks Canada (Depart ment of Canadian
Heritage), initiated reg u la tory actions to prohibit the pos ses -
sion and use of small lead sinkers and jigs by rec re ational
anglers fishing in National Wildlife Areas and National
Parks beginning in 1997. This parallel reg u la tory ini tia tive
was carried out under the Canada Wildlife Act and the
National Parks Act and targeted lead sinkers and jigs
weighing less than 50 g.
Since the ini ti a tion of these reg u la tory actions, the
Canadian Wildlife Service (CWS) has continued to assess
the effects of lead fishing sinkers and jigs on water birds
through doc u men ta tion of cases of mortality due to lead
sinker ingestion. The present report updates sci en tific infor -
ma tion presented in Scheuhammer and Norris (1995) and
discusses ini tia tives taken by Canada and other countries to
manage the issue of lead sinker ingestion and poisoning in
wild birds.
7
1. Rec re ational angling in Canada
1.1 Esti mating the number of rec re ational anglers in
Canada
Rec re ational angling in Canada is managed mainly by
the federal Depart ment of Fisheries and Oceans (DFO) and
its pro vin cial and ter ri to rial coun ter parts. In 1975, these
agencies initiated the Survey of Rec re ational Fishing in
Canada. Included in this nation ally coor di nated survey were
estimates of the total number of rec re ational anglers across
Canada, the level of angling effort in various regions, and the
social and economic impor tance of this activity across
Canada. The survey is conducted every five years.
The Nature Survey, formerly known as The Impor -
tance of Wildlife to Canadians or the Wildlife Survey, was
initiated in 1981 by Envi ron ment Canada in coop er a tion with
federal, pro vin cial, and ter ri to rial gov ern ments to obtain
infor ma tion about Cana di ans’ rec re ational interests in
wildlife and nature (Filion et al. 1993; DuWors et al. 1999).
Starting with the 1991 survey, Envi ron ment Canada began
incor po rat ing questions per tain ing to par tic i pa tion in rec re -
ational angling activ i ties. Together, the DFO and Envi ron -
ment Canada surveys provide infor ma tion on rec re ational
angling across Canada from 1975 to 1996. Estimates of sub -
sis tence angling are not included in these surveys.
DFO surveys indicate that, between 1975 and 1995,
the number of licensed anglers in Canada ranged from 4.64
to 5.18 million (DFO 1994, 1997, unpubl. data), whereas the
Envi ron ment Canada surveys estimated 5.4 million anglers in
1991 and 4.2 million in 1996 (Filion et al. 1993; DuWors et
al. 1999) (Table 1). These figures are slightly higher than
estimates by Scheuhammer and Norris (1995) that were
based on adult resident licensed anglers only. However, an
estimated 1.06–1.65 million unli censed indi vid u als,
including children and adults not required to purchase a
licence, also par tic i pate in rec re ational angling in Canada.
Unli censed anglers represent about 17–26% of total angling
par tic i pa tion (DFO 1994, 1997). Overall, about 5.5 million
people fish in Canada every year, or approx i mately 1 in 5
Canadians (DFO 1997; DuWors et al. 1999).
1.2 Geo graphic dis tri bu tion of rec re ational anglers in
Canada
The majority of rec re ational anglers fish within their
province or territory of residence. Almost two-thirds of all
annual open water rec re ational angling takes place in Ontario
and Quebec (Fig. 1) (DFO 1997). A small pro por tion of
Canadians (10% of all anglers) travel outside their province
or territory of residence to fish. In addition, an estimated
800 000 tourists, primarily from the United States, travel to
Canada every year to fish, rep re sent ing about 12% of all
anglers in Canada (Filion et al. 1993; DFO 1994, 1997;
DuWors et al. 1999).
There is con sid er able regional variation in total
(fresh wa ter plus saltwater) angling effort, ranging from 9
days per angler per year in the Yukon to 24 days in New -
found land (Fig. 2). Annual fresh wa ter angling effort
generally exceeded saltwater effort, ranging from 9 days per
par tic i pant in the Yukon to 19 days per par tic i pant in Nova
Scotia (DFO 1994). Fishing in fresh wa ter envi ron ments
accounts for 85% of all rec re ational angling effort (61
million days) in Canada, and the majority of this (55.5
million days) is open water activity (rather than ice fishing)
(DFO 1997).
1.3 Angling pressure in Canada and the United States
Angling pressure was cal cu lated by deter min ing the
total number of days spent angling (fresh plus salt water) in
various regions of Canada (based on DFO survey results)
and the United States and dividing by the regional area to
obtain an estimate of the mean number of angling days per
square kilometre per year. Overall, there was a general trend
of increas ing angling pressure from west to east-central
North America, with the highest levels reported in southern
Ontario and the north east ern United States.
1.3.1 Canada
In 1995, DFO estimated that 4.6 million licensed
Canadian anglers spent 55.5 million days open water fishing,
or an average of about 12 days per angler (DFO 1997). An
addi tional 5.5 million days were spent fishing through ice;
however, these data are not included in our analysis of
angling pressure, because lead poisoning asso ci ated with
fishing tackle is primarily an open water phe nom e non. Sub -
sis tence angling was not reported in the DFO surveys.
For the present report, total land area was used in cal -
cu lat ing angling pressure in the absence of specific data for
the area covered by lakes, rivers, etc. Thus, our estimates of
angling pressure may not coincide with creel census or other
local angling surveys.
8
Angling pressure reported at the pro vin cial/ter ri to rial
level ranged from <1 angler day per square kilometre in the
Northwest Ter ri tories to over 47 angler days per square
kilometre in Prince Edward Island (DFO 1997).
Addi tional infor ma tion on angling effort was obtained
from a 1991 survey in Ontario, which estimated angling
effort for eight admin is tra tive regions (OMNR 1993)
(Fig. 3). Within Ontario, where about 44% of all Canadian
angling occurs, the southern regions were subject to the
majority of the angling pressure. Angling pressure ranged
from 4.2 days per square kilometre in the Northern Region to
over 230 days per square kilometre annually in the Central
Region. Patterns of angling effort within indi vid ual
provinces are not currently available for other areas of
Canada.
1.3.2 United States
In 1996, an estimated 35 million people 16 years of
age or older par tic i pated in rec re ational fishing (exclusive of
ice-fishing activity) in the United States, spending over 625
million days fishing, or an average of 18 days per angler
(U.S. Depart ment of the Interior 1997). U.S. state angling
pressure estimates are con sid er ably greater than those for
Canadian provinces and ter ri to ries, ranging from 6.9 angler
days per square kilometre in Nevada and Montana to over
800 angler days per square kilometre in New Jersey (Fig. 4).
Although the number of anglers in the United States was
stable between 1991 and 1996, the number of angling days
rose from 511 million to over 600 million, leading to a sub -
stan tial increase in angling pressure in some states.
1.4 Summary
•In 1995, 4–6 million Canadian anglers spent 50–60
million days fishing in open water — on average, between
10 and 13 days per angler per year.
•Fresh wa ter angling rep re sents 85% of all rec re ational
angling in Canada; 65% of this occurs in Ontario and
Quebec.
9
Ta ble 1
Rec re ational an glers in Can ada (adapted from Filion et al. 1993; DFO 1994, 1997; DuWors et al. 1999)
Rec re ational an glers in Can ada (× 1 000 000)
Adult li censed anglers Children and other un li censed participants To tal
num ber of
an glers in
Can adaYear Res i dents Non -
res i dents Non-resident
non-Canadians
To tal
licenced
an glers Res i dents Non-
residents Non-resident
non-Canadians
To tal
un li censed
an glers
DFO surveys
1975 3.70 0.98 NAa4.68 1.40 0.25 NA 1.65 6.33
1980 4.20 0.97 NA 5.17 0.85 0.21 NA 1.06 6.23
1985 4.20 0.19 0.79 5.18 1.40 0.05 0.14 1.59 6.77
1990 4.00 0.19 0.77 4.96 NA NA NA NA 4.96b
1995 3.68 0.20 0.76 4.64 NA NA NA NA 4.64b
Mean 3.96 0.51 0.77 4.93 1.22 0.17 –1.43 5.79
1991 Wildlife Survey 5.44 0.86 6.30 NA NA NA NA 6.30
1996 Nature Survey 4.20 0.54 4.74 NA NA NA NA 4.74
Mean 4.82 0.70 5.52 ––––5.52
aNA = data not avail able.
bData source notes that these estimates are minimum values due to an inability to determine the numbers of unli censed anglers.
Figure 1
Pro por tion of the total number of open water rec re ational angling days spent
within various regions of Canada (total = 55.5 million angler days per year)
Figure 2
Estimated average annual angling effort per indi vid ual angler, by province
and nation ally (data from Filion et al. 1993; DFO 1994, 1997; DuWors et al.
1999)
10
Figure 3
Estimated rec re ational angling pressure in various regions of Ontario in 1991 (OMNR 1993)
Figure 4
Rec re ational angling pressure by province in Canada and by state in the United States (data from DFO 1997; U.S. Depart ment of the Interior 1997)
•Angling pressure in Canada ranges from <1 to 47 angler
days per square kilometre at the pro vin cial/ter ri to rial level
and increases to over 230 angler days per square
kilometre at the regional level in central Ontario.
•In 1996, 35 million U.S. anglers spent over 625 million
days fishing in open water; about 18 days per angler.
•Average angling pressure is greater in the United States
than in Canada and ranges from 7 to over 800 angler days
per square kilometre at the state level.
11
2. Esti mating the magnitude of lead sinker and jig use
2.1 Market demand
In 1995, Canadian anglers spent $2.5 billion, or an
average of about $533 per angler, on goods and services
directly related to rec re ational fishing (DFO 1997), a slightly
higher estimate than that reported in the 1991 Wildlife
Survey (Filion et al. 1993) and in Scheuhammer and Norris
(1995). Over 80% of these expen di tures were for food,
lodging, and trans por ta tion/travel. Fishing supplies including
bait, line, and fishing tackle rep re sented 8% ($194 million)
of anglers’ expenses (Fig. 5), or about $42 per resident
angler annually (DFO 1997). Using the estimated number of
anglers in Canada (5.5 million) and the average yearly
estimate of expen di ture per angler on sinkers derived by
Scheuhammer and Norris (1995) ($3.25 per year), it is
estimated that Canadian anglers spend about $17.9 million
per year buying fishing sinkers. Using the average retail cost
of sinkers ($0.032 per gram of lead), the mass of lead sold as
fishing sinkers annually in Canada is estimated to be about
559 tonnes. An unde ter mined addi tional amount of lead is
sold in the form of jigs. The majority of this annual purchase
of lead is destined to be deposited in the envi ron ment, with
virtually no chance of recovery or recycling.
Reg u la tions pro hib it ing the use of lead fishing sinkers
and jigs within National Wildlife Areas and National Parks
were initiated in 1997. These reg u la tions were estimated to
affect about 50 000 anglers and to reduce the use of lead
fishing sinkers and jigs by about 4–5 tonnes annually. Local
outreach efforts, including col lec tion and exchange
programs, combined with efforts to educate anglers on the
hazards to wildlife from lead sinkers and jigs, have helped to
reduce the demand for lead in some areas (e.g., Great Lakes
2000 Cleanup Fund 1995). However, together, these efforts
have resulted in a reduction of only about 1% in the
estimated annual purchase and use of lead sinkers and jigs
(Fig. 6). Rec re ational anglers continue to purchase in excess
of 500 tonnes of lead annually in the form of lead sinkers and
jigs.
Com par a tively, in the United States in 1996, anglers
spent US$37.8 billion, or about US$1100 per angler, on
goods and services directly related to fishing (U.S. Depart -
ment of the Interior 1997). Over 70% of these expen di tures
were for food, lodging, trans por ta tion, and spe cial ized
equipment. Tackle, including hooks, sinkers, swivels, and
other items attached to the fishing line, except lures and bait,
rep re sented 1% (US$376 million) of anglers’ expenses, or
about US$11 per angler per year. Using the estimated
number of anglers in the United States (35 million) and the
U.S. Envi ron men tal Pro tec tion Agency’s (EPA) estimate of
average annual expen di ture per angler on sinkers (US$2.50
per year), U.S. anglers spend about US$87.5 million
annually to buy lead fishing sinkers. Assuming a similar
average retail cost for sinkers as deter mined by
Scheuhammer and Norris (1995) for Canada ($0.032 per g of
lead) and con vert ing to U.S. currency (US$0.022 per g of
lead), the mass of lead sold as fishing sinkers annually in the
United States is about 3977 tonnes.
2.2 Import of lead fishing sinkers and jigs
Scheuhammer and Norris (1995) obtained import
volume estimates for “fishing sinkers for sportsmen” from
the Inter na tional Trade Division of Sta tis tics Canada for the
period 1988–1994. For the present report, we requested
infor ma tion for the period 1988–1998. The “fishing sinkers
for sportsmen” clas si fi ca tion includes all shapes and sizes of
small fishing sinkers used for rec re ational angling in Canada.
This commodity does not include jigs; therefore, import of
lead jigs would be in addition to amounts presented below.
Reports do not specify “leaded” versus “lead-free” products,
so it is possible that some imports may be lead-free, espe -
cially in recent years, in response to reg u la tions pro hib it ing
the use of leaded products in the United States, Britain, and
Canada. However, based on the lack of broad-scale reg u la -
tions in North America and the rel a tively limited avail abil ity
of lead-free products at the retail level, it is likely that the
vast majority of imported products are still being man u fac -
tured using lead.
Between 1988 and 1998, the wholesale value of
imported sinkers ranged from $0.42 million in 1990 to $3.18
million in 1995 (Sta tis tics Canada 1999). A con sid er able
increase in the annual imports of these products began in
1995. Prior to 1995, the average annual import of sinkers
was estimated to be $0.60 million. From 1995 to 1998, the
average import rose to an estimated $2.67 million annually.
Based on the estimated wholesale sinker value of about
$0.027 per g of lead (Scheuhammer and Norris 1995), these
values translate to an estimated 22.40 tonnes of lead in the
form of lead fishing sinkers annually prior to 1995 and 98.91
tonnes annually after 1995 (Fig. 7).
Canada imported lead sinkers from 20 different
countries between 1988 and 1998. The majority of sinkers
12
(65%) imported since 1993 were from Europe, espe cially
Ireland, Finland, and the United Kingdom (Fig. 8). Asian and
U.S. producers provided an estimated 20% and 14%, respec -
tively, of all sinkers imported into Canada. Sporadic imports
from other countries combined (Mexico, Costa Rica, El
Salvador, Sweden, Italy, Germany, Hungary, Egypt, Kenya,
Japan, and Hong Kong) comprised 1% of the total import
market value in Canada during this time. European imports,
primarily from the United Kingdom and Finland, were
highest in 1995 (Fig. 7). Annual imports from Ireland have
continued to rise since 1995 and accounted for 70% (80
tonnes) of total Canadian imports in 1998. The reasons
under ly ing these changing patterns of sinker import into
Canada have not been assessed.
2.3 Domestic pro duc tion of lead fishing sinkers and
jigs
Domestic pro duc tion of lead fishing sinkers in
Canada was pre vi ously estimated to be about 40 tonnes
annually (Scheuhammer and Norris 1995), with an addi tional
unde ter mined amount of lead used in the pro duc tion of
lead-headed jigs. Based on limited cor re spon dence with
some Cana dian-based companies, we estimate that domestic
pro duc tion of lead sinkers has not changed sub stan tially in
recent years. However, some companies that pre vi ously
produced only lead tackle have expanded their product lines
to include lead-free sinkers and jigs. Some of these
companies now produce alter na tive sinker products for sale
and have con trib uted to sinker exchange programs in Canada
and the United States.
Prior to 1995, lead sinker imports were estimated to
account for a rel a tively small pro por tion (<5%) of the total
market demand (Scheuhammer and Norris 1995). With the
dramatic increase in for eign-made sinkers that began in
1995, it is estimated that imported products may now
comprise as much as 18% of the current market, or almost
100 tonnes annually. The balance of the product used in
Canada (~400 tonnes) is believed to originate from home and
small business man u fac ture of lead sinkers that are then sold
to indi vid ual anglers, tackle dis trib u tors, and retailers.
Although we have no direct infor ma tion about home pro duc -
tion of sinkers in Canada, it is believed that such an industry
must exist, because the estimated annual purchase of sinkers
is sub stan tively higher than the estimated import plus
13
Figure 5
Estimated breakdown of the average Canadian angler’s annual budget of
approx i mately $600 (DFO 1997)
Figure 6
Estimated current pro por tional use of lead versus nonlead sinkers and jigs in
Canada
Figure 7
Estimated annual weight of sinkers imported into Canada from major
geo graph ical regions (imports from Africa, Mexico, and Central America
were neg li gi ble: combined total of less than 1 tonne for the decade)
Figure 8
Pro por tions of total sinker imports (1988–1998) from various world regions
(data from Sta tis tics Canada 1999)
domestic pro duc tion by rel a tively large tackle companies
(Fig. 9).
In the United States, an estimated 480 million lead
fishing sinkers (2500–2600 tonnes) are sold annually (U.S.
EPA 1994; Nussman 1994). Domestic pro duc tion of sinkers
by fewer than 10 major man u fac tur ing companies is
estimated to be about 1500 tonnes annually. Sinker imports
on average con trib ute only 320 tonnes to the market, while
do-it-yourself home man u fac ture for retail and personal use
together con trib ute about 875 tonnes (Nussman 1994)
(Fig. 10).
2.4 Esti mating envi ron men tal lead depo si tion from the
annual loss of sinkers and jigs
Fishing sinkers and jigs may be acci den tally dropped
into the water or may be lost if the hook or line becomes
entangled and the line breaks or is cut. Geo graphically, envi -
ron men tal depo si tion of lead in the form of lead fishing
sinkers and jigs would be con cen trated in areas of highest
angling pressure. It is assumed that the majority of sinkers
purchased annually are to replace those lost while fishing;
thus, the magnitude of lead depo si tion from the loss of lead
fishing weights can be estimated by mon i tor ing annual pro -
duc tion and sale. Angler ques tion naires can con trib ute addi -
tional useful infor ma tion.
During the summers of 1996 and 1997, research ers
from the Uni ver sity of Arizona inter viewed over 850 anglers
from 12 U.S. states where previous wildlife surveys had doc -
u mented elevated lead exposure and mortality in loons from
lead sinkers and jigs or where angling pressure was high
(Duerr 1999). Anglers were asked how long they had spent
fishing on the survey day and whether or not they had lost
any tackle that day. For all study sites combined, anglers
each reported losing, on average, 0.18 sinkers per hour, 0.14
pieces of fishing line per hour, and 0.23 hooks and lures per
hour. About 2% of anglers (16 of 859) reported releasing or
losing fish with tackle attached. At this rate, each angler
would have lost about 1 sinker for every 6 hours of fishing.
Similarly, British anglers were reported to have lost or
discarded an average of two or three sinkers per angling day
(Bell et al. 1985). Another survey conducted in 1986 in the
United States estimated that for every one split shot sinker
used, four to six might be spilled and lost (Lichvar 1994).
Split shot sinkers account for almost half of the total U.S.
sinker pro duc tion (U.S. EPA 1994). We are unaware of any
Canadian surveys to determine rates of sinker loss by
anglers; however, it is rea son able to assume that Canadian
anglers probably expe ri ence loss rates com pa ra ble to those
reported in the United States — about one sinker per angler
per angling day. Given this assump tion, approx i mately 66
million sinkers are lost annually in Canada. Annual angling
budget expen di tures estimated by the U.S. EPA (1994) and
Scheuhammer and Norris (1995) suggested that the average
angler purchases about 14 sinkers annually, or about one
sinker per angling day, com pa ra ble to the number estimated
lost. These studies indicate that annual sales of sinkers are
driven primarily by sinker losses.
In a 1999 lead assess ment report, the Minnesota
Pollution Control Agency estimated that 49 tonnes of lead
are used annually for fishing in Minnesota; however, no
specific data were available to indicate the pro por tion of this
lead that may be lost annually into lakes (Nankivel 1999). A
study by the New Zealand Depart ment of Con ser va tion
reported that retail outlets in the Lake Taupo, New Zealand,
area had sold approx i mately 4 tonnes of lead fishing tackle
over a 12-month period, providing an indi ca tion of the
annual losses within that region. Inves ti ga tions of the
impacts of lead pollution in this region are con tin u ing (Royal
Forest and Bird Pro tec tion Society 1999). Similarly, areas of
Canada that expe ri ence heavy angling pressure probably
expe ri ence rel a tively high local lead con tam i na tion from loss
of sinkers during angling.
Estimates of the local density of lost or discarded lead
fishing sinkers and jigs in the envi ron ment have been made
in the United Kingdom and the United States through visual
inspec tions of soils and sediments (Bell et al. 1985; Forbes
1986; Sears 1988), wet sieving sediment samples (Cryer et
al. 1987), drying sediments and hand sorting (Bell et al.
1985), or use of radi og ra phy (Sears 1988). More recently,
Duerr and DeStefano (1999) described the use of a metal
detector to estimate densities of sinkers on shore lines,
shallow sediments, and lake bottoms. Lead sinker density in
U.S. shoreline soil and sediments ranged from 0–0.01 sinkers
per square metre in areas of low angling pressure to 0.47
sinkers per square metre in areas with high angling pressure
(Duerr 1999). Lead sinker abundance was found to be higher
14
Figure 9
Sources of lead fishing tackle com pris ing the Canadian fishing sinker
market, 1995–1998
Figure 10
Sources of lead fishing tackle com pris ing the U.S. fishing sinker market,
based on 1994 estimates (total volume of sales ~2600 tonnes) (Nussman
1994)
in United Kingdom surveys, ranging from 0.9–16 sinkers per
square metre in River Thames sediments and shoreline (Sears
1988) to 24–190 sinkers per square metre of shoreline in
South Wales (Cryer et al. 1987). Results of these studies are
sum ma rized in Table 2.
In 1996, Envi ron ment Canada’s National Pollutant
Release Inventory (NPRI) estimated that 1699 tonnes of lead
were released into the Canadian envi ron ment by the indus -
trial sector (NPRI 1996). Ninety-five percent of these
releases were attrib ut able to the primary metal mining and
smelting indus tries. Releases to air and water by the mining
industry have decreased sub stan tially since the early 1990s,
and further decreases are antic i pated. Lead releases in the
form of spent shotshell ammu ni tion and the loss of fishing
sinkers and jigs are typically not formally reported within the
context of envi ron men tal lead emissions, such as the NPRI
inventory; thus, relative con tri bu tions to overall lead releases
from these sources are usually over looked.
Spent lead shot from hunting and target shooting was
estimated to con trib ute approx i mately 2400 tonnes of lead
annually to the Canadian envi ron ment, prior to reg u la tory
action beginning in the early 1990s (Scheuhammer and
Norris 1995). By September 1999, the use of lead shot was
pro hib ited for hunting most migratory game birds in all areas
of Canada (Canada Gazette 1997a), pre sum ably elim i nat ing
the con tri bu tion to envi ron men tal lead releases pre vi ously
made by waterfowl hunting. In addition, the use of lead shot
was pro hib ited for all hunting within National Wildlife Areas
(Canada Gazette 1996). Together, these reg u la tions should
reduce the depo si tion of lead shot into the envi ron ment from
hunting activ i ties by about 800 tonnes annually. With these
lead shot restric tions and continued indus trial declines in
emissions, rec re ational angling rep re sents an increas ing pro -
por tion (up to 14%, 559 tonnes) of the total amount of lead
annually dis charged into the Canadian envi ron ment (Fig.
11).
15
Ta ble 2
Studies re port ing den si ties of lost or dis carded sink ers
Coun try/state Lo ca tion Sub strate Sinkers/jigs per m2Ref er ence
United Kingdom
River Thames Sediments (<1 m)
Shoreline
0.9–6.2
1.0–16.3 Sears 1988
Woodstock Pool Fishing platforms 105.2 Bell et al. 1985
Llandindod Wells Lake Shoreline
Island
14.2
21.2 Forbes 1986
South Wales Shorelines with:
heavy angling
moderate angling
light angling
189.7
53.6
24.0
Cryer et al. 1987
United States
Arizona Arkansas Nuclear, Pope Shoreline 0.07 HFaDuerr 1999
Florida One Canaveral, Brevard Shoreline 0 HF Duerr 1999
Florida Merritt Island Refuge, Brevard/Volusa Shoreline 0.02 HF
0 OTbDuerr 1999
Idaho Henry’s Fork, Fremont Shoreline 0.08 HF
0.01 OT Duerr 1999
New Hampshire/
Maine Umbagog Lake, Coos, New Hampshire/Oxford, Maine Shoreline
Lake bottom
Snorkeling
0.05 HF
0.004
0.0 OT – 0.13 HF
Duerr 1999
Maine Rangeley Lake Refuge, Oxford/Franklin, Maine Lake bottom
Snorkeling
0–0.008 HF/OT
0.4 OT – 0.0 HF Duerr 1999
Michigan Seney Refuge, Schoolcraft Shoreline 0 HF
0.002 OT Duerr 1999
North Carolina Snake River, Mattamuskeet, Hyde Shoreline 0.01 HF
0.004 OT Duerr 1999
North Carolina Pungo District of Pososin, Lakes Hyde/Washington Shoreline 0 HF
0.003 OT Duerr 1999
North Virginia Ruby Lake, Refuge Pine Shoreline 0.47 HF
0.01 OT Duerr 1999
Wisconsin Turtle Flambeau, Flowage Iron Shoreline 0.0003 OT Duerr 1999
Vermont Missisquoi, Franklin Shoreline 0.1 HF
0 OT Duerr 1999
aHF = heavily fished (ar eas known to be sub ject to heavy an gling pres sure).
bOT = other (ar eas not sub ject to heavy an gling pres sure).
Figure 11
Estimated envi ron men tal lead releases in Canada from rec re ational angling
and other sources (total estimated depo si tion ~3800 tonnes/year)
2.5 Summary
•Canadian anglers spend an estimated $17.9 million
annually pur chas ing over 500 tonnes of lead in the form
of fishing sinkers. An unde ter mined addi tional amount of
lead is sold in the form of jigs.
•Reg u la tions pro hib it ing the use of lead fishing sinkers and
jigs within National Wildlife Areas and National Parks in
1997, together with local outreach efforts, have affected
about 1% of anglers and have reduced lead sinker and jig
demand by about 5 tonnes annually.
•Domestic pro duc tion and import of sinkers in Canada
averaged 140 tonnes annually between 1995 and 1998.
The balance of the sinker market in Canada
(approx i mately 400 tonnes) is believed to originate from
home and other small-scale pro duc tion.
•The U.S. sinker market was estimated to use 2500–2600
tonnes of lead annually, with home pro duc tion
con trib ut ing 875 tonnes (32%).
•Lead fishing sinkers and jigs may be acci den tally dropped
into the water or may be lost if the hook or line becomes
entangled and the line breaks or is cut.
•U.S. anglers lose an estimated one sinker every 6 hours of
fishing. Based on similar angling habits and methods in
Canada and the United States, it is assumed that Canadian
anglers expe ri ence a similar rate of sinker loss.
•Lost or discarded fishing sinkers and jigs introduce about
500 tonnes of metallic lead into the Canadian
envi ron ment annually and represent up to 14% of all lead
releases.
16
3. Lead sinker ingestion and poisoning in wildlife
3.1 Lead poisoning in wildlife
Elevated lead exposure and/or lead toxicosis in
wildlife have tra di tion ally been asso ci ated primarily with the
ingestion of spent lead shot from hunting, as well as
proximity to heavily travelled roads (i.e., lead from
gasoline), base metal mining, smelting, and refining activ i -
ties, and agri cul tural areas where lead arsenate pesticide was
used (Eisler 1988). More recently, lead poisoning —
primarily in Common Loons in North America (Pokras et al.
1993; Scheuhammer and Norris 1995) and swans in Great
Britain (O’Hallo ran et al. 1988; Sears et al. 1989) — has
been asso ci ated with the ingestion of lead fishing sinkers or
jigs.
Ingested lead sinkers and jigs may become lodged in
the gizzard, where metallic lead is oxidized and ionic lead
released as a result of the grinding action of the gizzard and
the acidic envi ron ment of the upper digestive tract. Ingestion
of a single lead sinker or lead-headed jig, which may
represent up to several grams of lead, is suf fi cient to expose
a loon or other bird to a lethal dose of lead (Pokras et al.
1993). In such cases of mortality from acute lead poisoning,
carcasses may appear to be in good body condition (Pokras
et al. 1993).
Common Loons with ingested lead fishing weights
present varying necropsy results, with no single finding pre -
dom i nat ing (Pokras et al. 1993). While proventricular dis ten -
tion, bile-stained gizzard lining, and green-stained vent
feathers are commonly observed in waterfowl with lead
poisoning from lead shot ingestion (Friend 1985), these signs
are often not present in loons that have ingested lead fishing
weights (Pokras et al. 1993). Absence of these signs, and the
good body condition in which loons are usually found,
suggested that mortality was rel a tively rapid due to acute
lead poisoning.
Four loons that ingested small lead fishing weights in
Atlantic Canada were found dead, in poor body condition,
and with renal lead con cen tra tions com pat i ble with lead
poisoning (Daoust et al. 1998). The gizzards of two of these
birds had chronic traumatic lesions caused by pen e tra tion of
a fishing hook. In these cases, both lead exposure and trauma
caused by pen e tra tion of a fishing hook were judged to have
con trib uted to the dete ri o rated body condition.
Diagnosis of lead shot or sinker ingestion by wild
birds may be made through radio graphic or fluoroscopic
exam i na tion of the gizzard or by deter mi na tion of tissue lead
levels, most commonly in liver and/or kidney and occa sion -
ally blood. Blood lead levels in Common Loons without lead
sinker ingestion are generally below 0.1 µg/mL. Loons
confirmed to have ingested lead sinkers dem on strate highly
elevated blood lead con cen tra tions (Table 3), con cur rent with
inhi bi tion of aminolevulinic acid dehydratase activity.
Although lead con cen tra tions in liver, kidney, and
bone tissue of most wildlife without lead shot or sinker
ingestion are generally below 5 µg/g dry weight, tissue con -
cen tra tions in Common Loons in Canada with confirmed
lead sinker or jig ingestion were as high as 142 µg/g dry
weight in liver and 726 µg/g dry weight in kidney (Table 3).
Similar results have been reported in the United States. In a
few cases, high lead exposure was found in indi vid u als that
did not show evidence of a lead sinker or jig in the gizzard at
the time of exam i na tion, but this was uncommon (Franson
and Cliplef 1993; Pokras et al. 1993; Scheuhammer and
Norris 1995). Evidence gathered to date indicates that
ingestion of lead sinkers and jigs is the only sig nif i cant
source of elevated lead exposure and lead toxicity for
Common Loons.
3.2 Lead sinker and jig ingestion cases in wildlife
Among the earliest published reports of lead
poisoning from sinker ingestion in North American wildlife
are those of Locke and Young (1973) (a Whistling Swan
Olor columbianus) and Locke et al. (1982) (three Common
Loons). By the early 1990s, research ers had estab lished
networks of wildlife biol o gists, wildlife rehabilitators, and
vet er i nar i ans to assist in reporting cases of lead poisoning in
wildlife asso ci ated with the ingestion of lead fishing sinkers
and jigs.
Scheuhammer and Norris (1995) sum ma rized 46
instances of mortality from lead sinker and jig ingestion in
Canada from eight wildlife species, including loons and
various waterfowl and raptors. Since 1995, at least 26 addi -
tional cases of mortality from lead sinker and jig ingestion
have been reported and include two new species: Herring
Gull Larus argentatus and snapping turtle Chelydra
serpentina (Table 4). Although lead sinkers were not directly
impli cated in its death, an endan gered Whooping Crane Grus
americana from western Canada was found to have elevated
lead levels in blood, kidney, and liver and may have ingested
a lead sinker (Snyder et al. 1991). Lead poisoning from
ingestion of lead shot and lead fishing sinkers was iden ti fied
17
as an important factor limiting efforts to rein tro duce the
Trumpeter Swan Cygnus buccinator in Ontario (Hunter
1995). Radio graphic analyses have also revealed lead fishing
weights in dead Great Blue Herons Ardea herodias, Dou -
ble-crested Cor mo rants Phalacrocorax auritus, Green
Herons Butorides virescens, and uniden ti fied gull and swan
species submitted to a wildlife rehabilitator in south west ern
Ontario (Twiss and Thomas 1998). Virtually all species of
piscivorous bird, as well as species that feed in nearshore
soils and sediments, are at risk of lead poisoning from inad -
ver tent con sump tion of lost or discarded lead sinkers.
In the United States, Perry (1994) compiled over 300
cases of sinker ingestion in over 20 species of wildlife,
including loons, swans, ducks, geese, cranes, pelicans, and
cor mo rants. Most recently, two species of turtle have been
found to ingest lead fishing sinkers. U.S. research ers have
now doc u mented lead sinker and jig ingestion in at least 371
indi vid u als from 23 different wildlife species (Table 5).
18
Ta ble 3
Sum mary of tis sue lead con cen tra tions for Com mon Loons with and with out
the pres ence of lead ar ti facts in their di ges tive sys tems
Tis sue con cen tra tions
(µg/g dry weight, ex cept blood, µg/mL)
Sourcea
Blood Liver Kid ney Bone (ra dius)
Without lead artifact in gizzard
Canada NA <5
(n = 28) <5
(n = 28) <5
(n = 28) 1
USA 0.01–0.05
(n = 16)
0.2–0.44
mean 0.24
(n = 10)
NA NA 2
With lead artifact in gizzard
Canada NA 17–142
mean 59.2
(n = 12)
18.6–727
mean 218
(n = 25)
2.7–11
mean 5.7
(n = 8)
1, 3, 4
USA 0.78, 2.03
(n = 2)
20–72
mean 46
(n = 4)
NA NA 2
aSources are as fol lows:
1. A. Scheuhammer, Ca na dian Wild life Ser vice, Na tional Wild life
Re search Cen tre, Carleton Uni ver sity, Raven Road, Ottawa, Ontario,
unpubl. data, 1999.
2. Pokras et al. (1992).
3. D. Camp bell, On tario Vet er i nary Col lege, Guelph Uni ver sity,
Guelph, On tario, unpubl. data, 1999.
4. P.-Y. Daoust, At lan tic Vet er i nary Col lege, Char lotte town, Prince
Ed ward Is land, unpubl. data, 1999.
Ta ble 4
Wild life spe cies doc u mented to have in gested lead fish ing sink ers or jigs in Can ada, 1964–1999
Spe cies n Lo ca tion Date Sourcea
Piscivorous birds
Common Loon Gavia immer 1British Columbia 1993 1
1Saskatchewan 1997 2
36 Ontario 1987–1999 3, 4
6Quebec 1964–1994 5, 6, 7, 8
4New Brunswick 1993–1997 9
6Nova Scotia 1992–1996
1Prince Edward Island 1990–1997
Common Merganser Mergus merganser 1Ontario 1990–1994 4
Herring Gull Larus argentatus 1Quebec 1993 8
Bald Eagle Haliaeetus leucocephalus 1British Columbia 1990–1994 1
Nonpiscivorous birds
Trumpeter Swan Cygnus buccinator 1British Columbia 1993 1
1Ontario 1995 4
Canada Goose Branta canadensis 4Ontario 1992–1998 4, 10
2Quebec un known 11
1New Brunswick un known 1
1Prince Edward Island 1992 12
Mallard Anas platyrhynchos 1Ontario 1993 9
Greater Scaup Aythya marila 1Ontario 1994 9
White-winged Scoter Melanitta fusca 1Ontario 1994 9
Other aquatic wildlife
Snapping turtle Chelydra serpentina 1Quebec 1994 11
Totals: 10 species 72 7 prov inces 1964–1999
aSources are as fol lows:
1. Langelier (1994).
2. M. Wayland, Canadian Wildlife Service – Prairie and Northern Region, unpubl. data.
3. K. Chubb, Avian Care and Research Foun da tion, Verona, Ontario, unpubl. data.
4. D. Campbell, Ontario Vet er i nary College, Guelph Uni ver sity, Guelph, Ontario, unpubl. data.
5. Parks Canada, Quebec, unpubl. data.
6. R. Ouellet, ministère de l’Agriculture, des Pêcheries et de l’Alimentation, Quebec, unpubl. data, 1994.
7. R. Ouellet, ministère du Loisir, de la Chasse et de la Pêche, Quebec, unpubl. data, 1968.
8. J. Rodrigue and L. Champoux, Canadian Wildlife Service – Quebec Region, unpubl. data.
9. P.-Y. Daoust, Atlantic Vet er i nary College, Char lotte town, Prince Edward Island, unpubl. data.
10. H. Pittel, Avicare Reha bil i ta tion Centre, Bowmanville, Ontario, unpubl. data.
11. M. Ouellet, Redpath Museum, McGill Uni ver sity, Montreal, Quebec, unpubl. data.
12. Bar row (1994).
19
Ta ble 5
Wild life spe cies doc u mented to have in gested lead fish ing sink ers or jigs in the United States, 1976–1999
Spe cies n Lo ca tion Year Sourcea
Piscivorous birds
Common Loon Gavia immer 1Florida 1993 1
34 Maine 1989–1999 2, 3
3Maine 1976–1991 4
5Massachusetts 1989–1999 2, 3
3Michigan 1988–1993 5
5Minnesota 1984–1990 6
4Minnesota 1976–1991 4
64 New Hampshire 1989–1999 2, 3, 7
1New Hampshire 1976 8
1New Hampshire 1976–1991 4
7New York 1983, 1986, 1989 9
12 New York 1994 10
9Vermont 1989–1999 2, 3
1Vermont 1976–1991 4
1Wisconsin 1980 8
2Wisconsin 1976–1991 4
American White Pelican Pelecanus erythrorhynchos 1Washington 1993 11
Brown Pelican Pelecanus occidentalis 45 Florida 1991–1993 1
Double-crested Cormorant Phalacrocorax auritus 26 Florida 1991–1993 1
1Maine 1994 7
Snowy Egret Egretta thula 1Florida 1991 1
Great Egret Ardea alba 3Florida 1991 1
Great Blue Heron Ardea herodias 1Massachusetts 1989–1993 7
8Florida 1991–1993 1
White Ibis Eudocimus albus 1Florida 1993 1
Mississippi Sandhill Crane Grus canadensis pulla 3Mississippi ?12, 13
Red-breasted Merganser Mergus serrator 1Florida 1993 1
Laughing Gull Larus atricilla 9Florida 1991–1993 1
Herring Gull Larus argentatus 1Florida 1993 1
Royal Tern Sterna maxima 7Florida ? 1
Nonpiscivorous birds
Whistling or Tundra Swan Cygnus columbianus 1Michigan 1988–1993 5
1New York 1986 14
1Maryland 1993 15
12 Minnesota 1983–1993 16
Trumpeter Swan Cygnus buccinator 15 Idaho 17
Mute Swan Cygnus olor 5Michigan 1988–1993 5
1Michigan ? 8
1Michigan ?18
1New York 1986 14
Canada Goose Branta canadensis 25 Minnesota 1983–1993 16
1Washington 1983–1993 11
Mallard Anas platyrhynchos 25 Minnesota 1983–1993 16
American Black Duck Anas rubripes 1New York 1994 10
Wood Duck Aix sponsa 6Minnesota 1983–1993 16
Redhead Aythya americana 10 New York 1994 10
1New York 1994 19
Other aquatic wildlife
Snapping turtle Chelydra serpentina 2Massachusetts 1990–1998 2, 20
Painted turtle Chrysemys picta 1Massachusetts 1990–1998 2
Totals: 23 species 371 13 states 1976–1999
aSources are as fol lows:
1. B. Suto, Suncoast Seabird Sanctuary, Indian Shores, Florida, unpubl. clinic records, 1994.
2. M. Pokras, Tufts Uni ver sity, School of Vet er i nary Medicine, North Grafton, Mas sa chu setts, unpubl. necropsy
reports, 1999.
3. Pokras et al. (1993).
4. Franson and Cliplef (1993).
5. Michigan Depart ment of Natural Resources, Rose Lake Wildlife Research Center, Wildlife Disease Lab o ra tory,
East Lansing, Michigan, unpubl. necropsy reports, 1993.
6. Ensor et al. (1992).
7. M. Pokras, Tufts Uni ver sity, School of Vet er i nary Medicine, unpubl. necropsy reports, 1994.
Continued
3.3 Types and sizes of lead fishing weights ingested by
wildlife
Sinkers used for most fresh wa ter angling range in
weight from 0.3 to 230 g and in length and diameter from
about 2 mm to 8 cm (Scheuhammer and Norris 1995). Lead
fishing weights that weigh less than 50 g or are smaller than
2 cm in any dimension are generally the size found to be
ingested by wildlife (Scheuhammer and Norris 1995),
although larger sizes can be ingested by larger water birds,
such as pelicans (C. Franson, U.S. Geo log i cal Survey, pers.
commun.).
For Common Loons collected in Canada, for which
the specific form of lead weight ingested was reported, (31
of 40) 77.5% were found to have ingested lead sinkers, 6 had
ingested lead-headed jigs and 3 loons were found to have
ingested both sinker and jig.
Lead weights ranging from 2-g split shot (4 mm2) to
20-g homemade sinkers (5 mm × 22 mm) have been
recovered from Common Loons in southern Ontario (K.
Chubb, Avian Care and Research Foun da tion, pers.
commun.). Ingested lead weights retrieved from loons in
New England ranged in size from 0.6 mm to 38 mm and
weighed as much as 23 g (M. Pokras, Tufts School of Vet er i -
nary Medicine, pers. commun.).
At least one-third of all sinker ingestion cases in loons
from Ontario and New England have also included the
presence of other fishing tackle, such as hooks, lines, etc. (K.
Chubb, Avian Care and Research Foun da tion, pers.
commun.; M. Pokras, Tufts School of Vet er i nary Medicine,
pers. commun.). Small pebbles were often asso ci ated with
the other two-thirds of the sinker ingestion cases, indi cat ing
that the sinkers may have been picked up from the bottom of
the water body while the birds were seeking grit material.
Franson et al. (2001) reported that small (2.4–9.5 mm) stones
were recovered from the stomach contents of 78% of
Common Loons found dead in New England and the south -
east ern United States; these data indicate the most probable
size range of sinkers that loons might inad ver tently ingest
from lake bottoms.
3.4 Relative impor tance of lead sinker ingestion as a
cause of Common Loon mortality
There are numerous causes of mortality in loons, the
most common of which are drowning in com mer cial fishing
nets, “trauma” from boat or other col li sions or gunshot
wounds, disease (espe cially botulism and aspergillosis), and
lead poisoning from sinker ingestion.
Avian botulism is a paralytic condition occurring
when birds consume a naturally occurring toxin produced by
the bacterium Clostridium botulinum. Type E botulism, in
par tic u lar, affects fish-eating birds and has, during a few
years, reached epidemic levels in the Great Lakes region,
causing sporadic outbreaks of mortality in Common Loons
and other fish-eating birds (Brand et al. 1988); however, it
has been diagnosed only infre quently elsewhere in the
United States or Canada. A par tic u larly severe and per sis tent
outbreak of Type E botulism began on Lake Erie during
1999–2000 and continues in 2002, with hundreds or
thousands of migrating Common Loons estimated to have
died of the disease (Campbell and Barker 1999).
Overwintering Common Loons occa sion ally expe ri -
ence large-scale die-offs, sometimes numbering in the
hundreds or thousands of indi vid u als. In these cases, the
majority of dead loons have been found to have succumbed
to an ema ci a tion syndrome char ac ter ized by loss of body fat,
atrophy of pectoral muscle, and hem or rhagic enteritis;
however, the etiology of this syndrome remains uncertain
(Forrester et al. 1997). Spitzer (1995) discussed various
sources of Common Loon mortality on marine wintering
areas, including storms, food lim i ta tion, entan gle ment in
fishing nets, and oil spills.
Aspergillosis, a fungal infection of the respi ra tory
tract, has been commonly diagnosed in dead loons, but in
most cases it is presumed to be secondary to other con di -
tions, because only unhealthy or starving birds are thought to
be unable to eliminate Aspergella spores from their lungs
(Wobeser 1981). Aspergillosis is thus asso ci ated with
immunosuppression, although the causes are generally
uncertain.
In eastern Canada and the United States, several
studies (primarily during the breeding season) have
compared the relative impor tance of different causes of
mortality and have concluded that lead sinker poisoning is
often one of the leading causes of mortality for Common
Loons. For example, in 105 Common Loon carcasses from
20
Ta ble 5 (continued)
Wild life spe cies doc u mented to have in gested lead fish ing sink ers or jigs in the United States, 1976–1999
8. Locket et al. (1982).
9. W. Stone, New York State Depart ment of Envi ron men tal Con ser va tion, Wildlife Resource Centre, Avon, New
York, unpubl. necropsy reports, 1990.
10. W. Stone, New York State Depart ment of Envi ron men tal Con ser va tion, Wildlife Resource Centre, Avon, New
York, unpubl. necropsy reports, 1994.
11. R. Ralston, U.S. Fish and Wildlife Service, National Wildlife Forensics Lab o ra tory, Ashland, Oregon, unpubl.
necropsy reports, 1994.
12. U.S. Fish and Wildlife Service (1992).
13. Windingstad et al. (1984).
14. W. Stone, New York State Depart ment of Envi ron men tal Con ser va tion, Wildlife Resource Centre, Avon, New
York, unpubl. necropsy reports, 1986.
15. Locke and Young (1973).
16. L. Wolf, Uni ver sity of Minnesota Wildlife Clinic, St. Paul, Minnesota, unpubl. clinic records, 1994.
17. Blus et al. (1989).
18. Gelston and Stuht (1975).
19. C. Franson, U.S. Geo log i cal Survey, National Wildlife Health Research Center, Madison, Wisconsin, unpubl.
necropsy reports, 1993.
20. Borkowski (1997).
New York state examined between 1972 and 1999, lead
poisoning and aspergillosis accounted for 21% and 23%,
respec tively, of overall mortality; no other single cause of
mortality exceeded 10% (Stone and Okoniewski 2001).
Similarly, in Atlantic Canada, 26% (8 of 31) of Common
Loons found dead were diagnosed to have died from lead
poisoning (Daoust et al. 1998). Lead poisoning from sinker
or jig ingestion was the single most important cause of
mortality for adult Common Loons in New England,
account ing for 45% (27 of 60) of recorded adult Common
Loon mortality in that region (Pokras et al. 1993) (Fig. 12).
Excluding mortality in saltwater envi ron ments, lead sinker
and jig ingestion accounts for over half (53%) of the reported
adult loon deaths in the New England states (M. Pokras,
Tufts School of Vet er i nary Medicine, unpubl. data).
In the early 1990s, surveys conducted in Ontario and
Atlantic Canada dem on strated that lead poisoning from the
ingestion of lead fishing sinkers and jigs was a leading cause
of death in adult Common Loons, account ing for about
15–30% of reported mortality (Scheuhammer and Norris
1995). Drowning as a result of entan gle ment in fishing lines
and disease, the other leading causes of death in adult loons,
accounted for an addi tional 29% of reported deaths in
Canada. In some areas (e.g., northern Quebec), Aborig i nal
harvest of loons probably accounts for a sig nif i cant pro por -
tion of local or regional loon mortality (Coad 1994);
however, in general, loons are not hunted in North America.
Since the early 1990s, lead sinker/jig ingestion has accounted
for approx i mately 22% (59 of 264) of the total reported
mortality in adult Common Loons examined in Canada
(Table 6). Figure 13 shows the relative impor tance of
different mortality factors for Common Loons in Ontario and
Atlantic Canada, the regions having the most data on loon
mortality in Canada.
In Michigan, out of 180 loon carcasses examined
between 1987 and 2001, 42 (23%) were judged to have died
from lead poisoning, usually from sinker ingestion, whereas
drowning accounted for 24% and “trauma” 21% of total
mortality (Michigan Depart ment of Natural Resources,
unpubl. data). In Minnesota, lead poisoning accounted for
between 5% (Pichner and Wolff 2000) and 17% of reported
Common Loon mortality (Ensor et al. 1992).
Although much of the concern regarding lead
sinker/jig ingestion by North American wildlife has focused
on Common Loons, sinker and jig ingestion may be an
important cause of death in other water birds as well. In a
4-year study of Mute Swans Cygnus olor along the River
Thames in England, Sears et al. (1989) found ingestion of
sinkers and jigs to be the single greatest cause of illness,
account ing for 55% of moribund indi vid u als. Lead sinker
21
Ta ble 6
Per cent age of to tal re ported mor tal ity in adult Com mon Loons at trib uted to
lead sinker/jig in ges tion in Ca na dian and U.S. stud ies
Area of study % mor tal ity Sourcea
Canada
Saskatchewan 5 (1 of 21) 1
Ontario 18 (21 of 114) 2
Ontario 30 (19 of 63) 3
Quebec 6 incidental reports
(6 of 6)
4, 5
New Brunswick, Nova Scotia, Prince
Edward Island 17 (4 of 23) 6
New Brunswick, Nova Scotia, Prince
Edward Island 22 (8 of 37) 7
United States
18 states combined 5 (11 of 222) 8
Michigan 40 (15 of 38) 9
Minnesota 17 (37 of 221) 10
New England states 53 (98 of 185) 11
aSources are as fol lows:
1. M. Wayland, Canadian Wildlife Service – Prairie and Northern
Region, unpubl. data, 1997.
2. D. Campbell, Ontario Vet er i nary College, Guelph Uni ver sity,
Guelph, Ontario, unpubl. data, 1991–1998.
3. K. Chubb, Avian Care and Research Foun da tion, Verona, Ontario,
unpubl. data, 1983–1998.
4. Parks Canada, Quebec, unpubl. data, 1964–1988.
5. R. Ouellet, ministère de l’Agriculture, des Pêcheries et de
l’Alimentation, Quebec, unpubl. data, 1994.
6. P.-Y. Daoust, Atlantic Vet er i nary College, Char lotte town, Prince
Edward Island, unpubl. data, 1992–1994.
7. P.-Y. Daoust, Atlantic Vet er i nary College, Char lotte town, Prince
Edward Island, unpubl. data, 1994–1998.
8. Franson and Cliplef (1993).
9. Poppenga et al. (1993).
10. Ensor et al. (1992).
11. M. Pokras, Tufts Uni ver sity, School of Vet er i nary Medicine, North
Grafton, Mas sa chu setts, unpubl. data, 1989–1998.
Figure 12
Relative impor tance of different causes of adult Common Loon mortality in
New England between 1989 and 1992 (n = 60) (data from Pokras et al.
1993)
Figure 13
Relative impor tance of different causes of adult Common Loon mortality in
Canada (based on cases reported in Ontario and Atlantic Canada between
1983 and 1995; n = 122)
ingestion has also been doc u mented as an important cause of
mortality in swans in Ireland (O’Hallo ran et al. 1988).
Recently, Franson and col leagues (C. Franson, U.S.
Geo log i cal Survey, pers. commun.) examined carcasses of
2241 indi vid ual birds of 29 species from the United States
that died in reha bil i ta tion centres or were found dead in the
field for the presence of ingested or entangled fishing tackle
and evaluated radio graphs of live birds trapped in the field
for images con sis tent with fishing weights and other tackle.
Ingested lead sinkers were found most fre quently in
Common Loons at a rate of 3.5% (n = 313) and in Brown
Pelicans Pelecanus occidentalis at a rate of 2.7% (n = 365).
Ingested lead fishing weights were also found in 1 of 81
Dou ble-crested Cor mo rants and 1 of 11 Black-crowned
Night-Herons Nycticorax nycticorax.
Doc u menting wildlife mortality from lead sinker
ingestion has tra di tion ally depended largely on the volunteer
par tic i pa tion of cottagers, anglers, boaters, etc. who come
across a carcass and notify an appro pri ate pro vin cial or
federal wildlife agency. Despite an increased awareness of
the lead poisoning issue among wildlife research ers, vet er i -
nary colleges, wildlife rehabilitators, and others, it is unlikely
that such a volunteer effort documents more than a small per -
cent age of the total number of lead sinker poisoning cases.
3.5 Sinker ingestion by wildlife — Spatial dis tri bu tion
Mortality asso ci ated with lead sinker or jig ingestion
in wildlife has been reported in seven Canadian provinces
and 13 U.S. states (Fig. 14). Common Loon mortality as a
result of ingestion of lead sinkers or jigs has been reported in
seven provinces and nine states. Reports of lead sinker
ingestion by wildlife have come primarily from eastern
Canada (espe cially Ontario and the Maritimes) and the north -
east ern United States (espe cially New England); despite
occa sional reports of lead sinker ingestion in other wildlife
species, concerted research efforts have focused on Common
Loons.
An average of six cases of wildlife mortality from
sinker ingestion have been doc u mented annually in Canada
between 1987 and 1998, and about 20 cases have been
reported annually in the United States during a similar time
period (1983–1998). The frequency of sinker ingestion
reports varies geo graph i cally. In Canada and the United
States, the highest average number of annual ingestion cases
originate from southern Ontario and New Hampshire, respec -
tively. These are areas that expe ri ence rel a tively high rec re -
ational angling pressure and also a rel a tively high degree of
research and mon i tor ing effort.
3.6 Sinker ingestion by wildlife — Temporal trends
3.6.1 Annual trends
CWS, in part ner ship with vet er i nary colleges and
wildlife reha bil i ta tion centres, doc u mented an average of 3–6
cases of sinker or jig ingestion and poisoning annually prior
to 1995 (K. Chubb, Avian Care and Research Foun da tion,
unpubl. data; D. Campbell, Ontario Vet er i nary College,
unpubl. data; P.-Y. Daoust, Atlantic Vet er i nary College,
unpubl. data). Since 1995, these orga ni za tions have each
continued to report a few cases of lead sinker ingestion in
Common Loons annually. However, few loon carcasses are
found and submitted for patho log i cal/tox i co log i cal analyses
each year. It is probable that many more loons die of lead
poisoning than are actually found and submitted for
necropsy.
3.6.2 Seasonal trends
Sinker ingestion has been reported in Common Loons
from April through December in Ontario and from May to
December in New England. For Ontario and New England,
19% (5 of 26) and 31% (8 of 26), respec tively, of all loons
for which the month of ingestion is known have ingested
their lead sinker or jig in August.
Lead poisoning rates of Mute Swans in the United
Kingdom were a function of the abundance of lead sinkers in
river sediments, but not of the abundance of sinkers on the
shores of the river (Sears 1988), indi cat ing that swans ingest
sinkers mainly while foraging in sediments. Along the River
Thames, reports of elevated blood lead levels and lead
poisoning of Mute Swans decreased following the closure of
the fishing season, sug gest ing that the avail abil ity of sinkers
is greatest when anglers are most active. Lost tackle may
settle deeper into sediments as time passes (Birkhead 1983;
Sears 1988) and may thus become increas ingly unavail able
for ingestion. Indeed, since a ban on lead sinkers was estab -
lished in Britain in 1986, the Mute Swan pop u la tion decline
has dra mat i cally reversed (Kirby et al. 1994).
3.7 Angling pressure and the incidence of sinker
ingestion in wildlife
Angling pressure in Canada ranges from <1 to 47
angler days per square kilometre at the pro vin cial/ter ri to rial
level and increases to over 230 angler days per square
kilometre at the regional level in central Ontario (see
section 1). The highest frequency of reports of lead sinker
poisoning in wildlife was reported in southern Ontario
(n = 45), an area where angling pressure can exceed 100
angler days per square kilometre. Regional/local angling
pressure estimates for other provinces, par tic u larly those in
which cases of sinker poisoning were reported, were not
available. This infor ma tion would be ben e fi cial in iden ti fy -
ing other locations where loons and other water birds are at
sig nif i cant risk of sinker/jig ingestion.
Wildlife mortality asso ci ated with lead sinker and jig
ingestion occurs within regions of Canada and the United
States where con sid er able rec re ational angling pressure
occurs (Figs. 15 and 16; Table 7). Angling pressure is often
greater in the United States than in Canada and can exceed
500 angler days per square kilometre per year at the state
level. In the United States, sinker and jig ingestion has been
reported mostly in states with angling pressures exceeding
100 angling days per square kilometre annually. The greatest
numbers of wildlife mortality cases have been reported in
Florida (n = 103), New Hampshire (n = 78), Maine (n = 37),
and New York (n = 21).
3.8 Summary
•Wildlife, primarily water birds, ingest fishing sinkers and
jigs during feeding, either by mistaking them for food
22
23
Figure 14
Dis tri bu tion of reported incidents of wildlife mortality asso ci ated with lead fishing sinker and jig ingestion in Canada and
the United States. Numbers of different species per province or state are also indicated.
Figure 15
Rec re ational angling pressure in Canada and the United States, with an indi ca tion of those provinces and states where
wildlife mortality from lead sinker or jig ingestion has been reported
24
Figure 16
Regions of eastern Canada and the United States with high rec re ational angling pressure, overlain with locations of known incidents of Common Loon
mortality (black circles) from ingestion of lead fishing sinkers or jigs
Ta ble 7
An gling ef fort in ar eas of North Amer ica where sinker/jig in ges tion has been re ported in Com mon Loons and other
wild life (data from OMNR 1993; DFO 1997; U.S. De part ment of the In te rior 1997)
Area
Num ber of
re ported
cases of
sinker/jig
poi son ing
Num ber of
rec re ational
an glers
(mil lions)
Num ber of
days per year
spent an gling
(mil lions)
Av er age
an nual
num ber of
days per
an gler Geo graphic
area (km2)
An gling
pres sure
(an gler
days/km2)
Canada 72
in di vid u als
(10 spe cies)
4.63 55.5 13 9 922 385 5.6
British Columbia 30.71 8.34 11.7 948 595 8.8
Saskatchewan 10.18 2.23 13 651 900 3.4
Ontario (total) 45 2.62 31.4 11.8 1 067 582 29.3
Northwest Region 30.25 1.93 7.6 228 310 8.5
North Central Region 40.13 1.14 9.1 211 826 5.4
Northern Region 30.12 1.45 12.0 346 281 4.2
Northeast Region 40.35 4.10 11.9 105 994 38.7
Algonquin Region 70.42 4.37 10.5 43 182 101.3
Eastern Region 17 0.34 3.77 11.2 32 842 114.7
Central Region 50.55 8.77 15.9 36 879 237.9
Southwest Region 10.34 4.53 13.5 62 268 72.7
Quebec 10 1.08 10.9 10.1 15 406 803 7.1
New Brunswick 50.09 0.91 10.5 73 435 12.4
Nova Scotia 60.06 1.15 18.1 55 490 20.8
Prince Edward Island 20.01 0.27 19.7 5 655 47.1
Continued next page
items or by consuming lost bait fish with the line and
sinker still attached.
•Ingestion of a single lead sinker or lead-headed jig, which
may represent up to several grams of lead, is usually
suf fi cient to expose a loon or other bird to a lethal dose of
lead.
•Evidence gathered to date indicates that lead sinker and
jig ingestion is the only sig nif i cant source of elevated lead
exposure and lead toxicity for Common Loons.
•Lead sinker and jig ingestion has been doc u mented in 10
wildlife species in Canada, including fish-eating birds
(Common Loon, Common Merganser Mergus merganser,
Herring Gull), waterfowl (Trumpeter Swan, Canada
Goose Branta canadensis, Mallard Anas platyrhynchos,
Greater Scaup Aythya marila, White-winged Scoter
Melanitta fusca), raptors (Bald Eagle Haliaeetus
leucocephalus), and snapping turtles; in the United States,
ingestion of lead sinkers and jigs by over 20 species of
wildlife, including swans, cranes, pelicans, and
cor mo rants, has been doc u mented.
•Lead fishing weights that weigh less than 50 g or are
smaller than 2 cm in any dimension are generally the size
that has been found to be ingested by wildlife.
•Lead sinker or jig ingestion is the single most important
cause of death of adult Common Loons reported in
Canada and the United States, commonly exceeding
deaths asso ci ated with entan gle ment in fishing gear,
trauma, and disease.
•Doc u mented cases of wildlife mortality from lead sinker
ingestion have come largely from ser en dip i tous discovery
of carcasses by cottagers, anglers, boaters, and others.
Con se quently, the total number of loons or other wildlife
that die of lead poisoning from sinker ingestion cannot be
con fi dently estimated.
•Lead sinker and jig ingestion in wildlife has been reported
in seven provinces and 13 U.S. states.
•In Canada, about six cases of sinker ingestion and
poisoning in wildlife (mostly Common Loons) are
reported annually, account ing for between 17 and 30% of
reported adult loon mortality in Ontario and Atlantic
Canada. In the United States, an average of 20 cases of
sinker and jig ingestion are reported annually.
•Common Loons have been found to ingest sinkers from
April through December in Ontario, with the majority of
cases reported in August.
•In Canada, the greatest frequency of wildlife mortality
asso ci ated with lead sinker or jig ingestion occurs in
southern Ontario, where angling pressure can exceed 100
angler days per square kilometre in some areas.
•In the United States, wildlife mortality asso ci ated with
lead sinker or jig ingestion was reported most fre quently
in Florida and New England, where state-level angling
pressures ranged from 60 to over 300 angler days per
square kilometre.
25
Ta ble 7 (cont’d)
An gling ef fort in ar eas of North Amer ica where sinker/jig in ges tion has been re ported in Com mon Loons and other
wild life (data from OMNR 1993; DFO 1997; U.S. De part ment of the In te rior 1997)
Area
Num ber of
re ported
cases of
sinker/jig
poi son ing
Num ber of
rec re ational
an glers
(mil lions)
Num ber of
days per year
spent an gling
(mil lions)
Av er age
an nual
num ber of
days per
an gler Geo graphic
area (km2)
An gling
pres sure
(an gler
days/km2)
United States 153
(23 spe cies)
35.3 628.2 17.8 9 381 920 66.9
Florida 103 2.9 45.5 15.9 140 255 324.2
Idaho 15 0.48 4.4 9.1 213 445 20.7
Maine 37 0.36 5.1 14.4 80 275 63.7
Maryland 10 0.72 10.2 14.4 25 480 500.1
Massachusetts 90.70 10.1 14.4 20 265 400.1
Michigan 11 1.82 28.7 15.7 147 510 194.6
Minnesota 68 1.54 27.0 17.6 206 030 131.1
Mississippi 30.58 9.7 16.8 122 335 79.6
New Hampshire 78 0.27 3.5 13.3 23 290 152.0
New York 21 1.71 29.4 17.2 122 705 239.3
Vermont 10 0.19 2.0 10.4 24 015 81.2
Washington 21.01 12.9 12.8 172 265 74.7
Wisconsin 31.47 17.1 11.6 140 965 121.5
4. Can pop u la tion-level effects of lead sinker
poisoning be deter mined for Common Loons in
Canada?
4.1 Back ground
In eastern North America, various anthropogenic
factors have been shown to adversely influence the health
and/or repro duc tive success of Common Loons. These
include direct effects — such as mercury poisoning from
point source con tam i na tion of water sheds (Barr 1986); lead
poisoning from sinker/jig ingestion (Scheuhammer and
Norris 1995; Twiss and Thomas 1998); drowning in fishing
gear and fatal trauma caused by collision with motor boats
and personal watercraft (Miconi et al. 2000) — and indirect
effects — from lake acid i fi ca tion, which both dimin ishes
food supply for loons and is asso ci ated with increased
mercury con cen tra tions in fish (Alvo et al. 1988;
Scheuhammer and Blancher 1994; McNicol et al. 1995a);
and cottage devel op ment, which may remove shoreline
breeding habitat and increase dis tur bance by human activity
(Heimberger et al. 1983).
While the effects of these envi ron men tal stressors
have been doc u mented — and there is no doubt that they can
cause direct mortality, increased sus cep ti bil ity to other
stressors, and/or reduced repro duc tive success in loons —
rel a tively little is known about their pop u la tion-level effects.
In areas where the relative impor tance of different mortality
factors has been assessed, poisoning from ingestion of lead
sinkers or jigs has often been dem on strated to be a major
cause of death for adult loons on their breeding grounds
(Pokras et al. 1993; Scheuhammer and Norris 1995). Rel a -
tively long-term studies indicate that 22–53% of reported
adult loon mortality in eastern North America is attrib ut able
to lead sinker and jig ingestion (section 3). Indeed, in New
England, on the southern edge of the Common Loon’s
breeding range, loon pop u la tion numbers are low and lead
poisoning incidence is par tic u larly high; adult mortality from
lead poisoning is suspected to be a potential con trib ut ing
factor limiting pop u la tion growth (D. Major, U.S. Fish and
Wildlife Service, pers. commun.).
One obstacle to the goal of eval u at ing pop u la tion
effects of lead poisoning or other envi ron men tal stressors in
Common Loons is a lack of under stand ing of the appro pri ate
spatial and temporal scales at which loon pop u la tions are
regulated. What defines a Common Loon “pop u la tion”
genet i cally is unde ter mined, but research to elucidate this is
ongoing, using DNA markers (D. Evers, BioDiversity
Research Institute, pers. commun.). Once known, such infor -
ma tion, coupled with infor ma tion on dispersal and
repro duc tive param e ters using indi vid u ally marked birds,
would allow us to better define pop u la tions; to assess the
degree of inter change among pop u la tions; and to determine
the impor tance of source–sink effects, where indi vid u als
from healthy pop u la tions with high pro duc tiv ity (sources)
disperse into less optimal habitats (sinks) in which pro duc tiv -
ity does not com pen sate for adult mortality (Pulliam 1988;
Bernstein et al. 1991; Rodenhouse et al. 1997).
Because loons are long-lived, with low rates of
mortality and repro duc tion (they breed every year, lay two or
very rarely three eggs, and live up to 25 years; McIntyre and
Barr 1997), there can be a longer lag time between envi ron -
men tal change and response in loon pop u la tion size than for
many other birds, making early detection of stressor effects
difficult. However, measures of pro duc tiv ity have been used
to provide an indi ca tion of the relative health of local or
regional loon pop u la tions (Barr 1986; Kerekes and Masse
2000). Pro duc tiv ity is a function of a number of variables,
including the age (expe ri ence) of breeders, health of
breeding pairs (including the influence of con tam i nant
exposure), habitat quality (avail abil ity of nesting sites, food
supply, etc.), weather con di tions during breeding (e.g., high
water levels can flood nests), and mortality rates during
migration and overwintering (if pro duc tiv ity is measured on
an annual basis). Deter mining the effects of envi ron men tal
stressors on loon pop u la tions thus requires spatially
extensive, long-term data.
Some research to model the effects of envi ron men tal
stressors on Common Loon pop u la tions has been attempted
in the northern United States, at the southern edge of the
species’ breeding range (Evers et al. 2001). In Canada,
long-term mon i tor ing has evaluated the effects of lake acid i -
fi ca tion on loon repro duc tive success under the Long-Range
Transport of Air Pol lut ants program (McNicol et al. 1987;
Wayland and McNicol 1990), and models have been
generated to predict the effects of changing sulphate depo si -
tion patterns (Blancher et al. 1992; McNicol 1999).
Meanwhile, research in Atlantic Canada has focused on
studying the asso ci a tions between methylmercury exposure
and loon pro duc tiv ity (Burgess et al. 1998a,b; Kerekes and
Masse 2000). However, little is known about the dispersal,
philopatry, site fidelity, mortality rates, and long-term repro -
duc tive success of loons anywhere in Canada.
In this section, we report on the spatial dis tri bu tion
and abundance of Common Loons in different regions of
Canada; provide estimates of national and pro vin cial
26
pop u la tion sizes of loons in Canada; report pop u la tion trends
in different geo graph ical regions using available data
sources; and, finally, explore some pos si bil i ties for
modelling loon pop u la tions and pre dict ing pop u la tion effects
of envi ron men tal stressors. Spe cifically, we examine the
following questions:
•Which areas (provinces/ter ri to ries/ecozones) hold the
greatest numbers of loons? Where do loons occur at
highest density?
•What is the temporal variation in loon pop u la tions from
these different geo graph ical areas? Is there evidence that
loon pop u la tions are stable, increas ing, or decreas ing?
•What level of philopatry do loons show? What are the
patterns (distances, direc tions) of dispersal from natal
sites? What is the extent of movement between adjacent
lakes? What migration routes do Canadian loons use, and
where do loons from specific breeding locations spend the
nonbreeding season? (The latter is critical to evaluate
mortality factors that act outside the breeding season and
to inves ti gate cumu la tive con tam i nant loads incurred
during the winter.)
•How does the spatial dis tri bu tion of the loon pop u la tion
match geo graph ical patterns of exposure to known
anthropogenic stressors? For example, what pro por tion of
the pop u la tion is at sig nif i cant risk from lead sinker/jig
ingestion?
Finally, we propose 1) a matrix pop u la tion modelling
approach to determine the effect of indi vid ual stressors on
Common Loon pop u la tions and 2) a spatially extensive
approach that uses geo graphic infor ma tion systems (GIS) to
overlay data on known loon pop u la tions and their pro duc tiv -
ity with the dis tri bu tion of multiple anthropogenic stressors
(e.g., acidified envi ron ments, envi ron ments with elevated
mercury con cen tra tions in fish, and envi ron ments that expe -
ri ence high rec re ational angling pressure).
4.2 Spatial patterns of abundance
Wetlands Inter na tional has estimated the global
Common Loon pop u la tion at 500 000–700 000 indi vid u als
(Rose and Scott 1997), and latest pop u la tion estimates for
Canada indicate a minimum of 544 562 indi vid u als (239 401
ter ri to rial pairs; Table 8). Approx i mately 82% of the North
American range and 81% of the western hemi spheric range
of the Common Loon is in Canada (A. Couturier, Bird
Studies Canada, pers. commun.). This means that Canada has
by far the greatest respon si bil ity of the world’s nations for
Common Loon con ser va tion and man age ment. The majority
of the Canadian pop u la tion occurs in two provinces (Ontario
and Quebec) and the Northwest Ter ri tories (Fig. 17). An
addi tional 30 000–35 000 adults reside in the United States,
and a few hundred to 2000 indi vid u als reside in Greenland
and Iceland (Evers 2000).
In Canada, Common Loons breed from the tree line
south to the Canada–U.S. border. Highest pop u la tion
densities are in the Mixedwood Plains and Boreal Plains
ecozones. Although Common Loons do occur in the Arctic
(e.g., southern Baffin Island), their densities are much lower
in far northern areas than in southern parts of Canada. Much
of their range overlaps the Canadian Shield, where there are
many large, deep water, oligotrophic lakes with large
pop u la tions of small fish (Vogel 1997). Loons prefer to
breed on large lakes (>5 ha); where lakes are small,
multi-lake ter ri to ries may occur (Evers et al. 2000). In some
areas, high densities of breeding loons overlap with pop u la -
tions of humans in the “cottage country” of southern Canada
and the northern United States. It is for these regional loon
“pop u la tions” that the threat of sinker ingestion and
poisoning is highest.
27
Ta ble 8
Es ti mated num ber of Com mon Loon ter ri to rial pairs and in di vid u als in Can -
ada (mod i fied from Evers [2000] to in clude ad di tional in for ma tion)
Prov ince/ter ri tory Num ber of
ter ri to rial pairs Num ber of
in di vid ual adults Sourcea
Ontariob97 000 232 800 1
Quebecb50 000 120 000 2
Northwest Territoriesb45 000 108 000 3
British Columbiab25 000 60 000 4
Manitobac10 000–12 000 28 800 5
Nunavutb5 000 12 000 3
Saskatchewan 1 500–2 000 4 800 6
Nova Scotiad1 200 2 880 7
New Brunswickd1 000 2 400 7
Alberta 1 000 2 400 8
Yukon 200 480 9
Prince Edward Island 1 2 10
Newfoundland and
Labrador Not avail able
Estimated total 236 901 – 239 401 574 562
aSources are as fol lows:
1. Wayland and McNicol (1990).
2. D. Bordage, Canadian Wildlife Service – Quebec Region, pers.
commun.
3. J. Hines, Canadian Wildlife Service – Prairie and Northern Region,
pers. commun.
4. A. Breault, Canadian Wildlife Service – Pacific and Yukon Region,
pers. commun.
5. B. Koonz, Manitoba Depart ment of Natural Resources, pers.
commun.
6. A. Brazda, U.S. Fish and Wildlife Service, pers. commun.
7. Erskine (1992).
8. Fed er a tion of Alberta Nat u ral ists, pers. commun.
9. Evers (2000).
10. J. Kerekes, pers. commun. to Evers (2000).
bNumbers were extrap o lated mainly from aerial waterfowl survey data, in
which “ter ri to rial pairs” of birds were deter mined during spring and
summer. Loons are usually counted inci den tally in these surveys and may
tend to be under es ti mated. Because only 80% of the adult loon
pop u la tion actually occupies ter ri to ries as breeding pairs, a 20% “buffer
pop u la tion” has been added to these estimates (Evers 2000).
In Quebec, annual Eastern Black Duck Joint Venture (EBDJV)
heli cop ter surveys covering an area of 500 000 km2 counted 25 000
breeding pairs in 1997. Because the survey focused on dabbling ducks, it
is likely that Common Loons were under es ti mated; therefore, the number
of loons was doubled to give 50 000 pairs (D. Bordage, Canadian
Wildlife Service – Quebec Region, pers. commun.). This estimate was
within the range reported by Evers (2000) (75 000 pairs) and DesGranges
and Laporte (1979) (35 000 pairs) for Quebec.
In Ontario, survey plots (2 × 2 km) were located sys tem at i cally (25 plots
to a block with 100-m sides) using a Universal Trans verse Mercator
(UTM) mapping grid com pris ing nine block across most of north east ern
Ontario between latitude 45° and 48°N (McNicol et al. 1987; Ross 1987;
Ross and Fillman 1990).
c A coarse estimate based on 30 years of birding expe ri ence in the
province. (Extrap o la tions from lake area and sampled loon densities are
not appro pri ate for Manitoba because of the many large lakes with no
loons.)
d Estimates for Nova Scotia were based on assuming 1–2 pairs of loons in
each 10 × 10 km2 square surveyed that had confirmed or probable
breeding evidence during the Maritime Breeding Bird Atlas survey, plus
a small fraction added to account for unsampled squares. Prince Edward
Island had no breeding evidence before 1992, but there was one brood
record (sent to the Nest Records Scheme) a year later (A.J. Erskine,
Canadian Wildlife Service – Atlantic Region, pers. commun.).
According to the Breeding Bird Survey (BBS), the
highest loon densities in Canada are found in north west ern
Ontario, west-central Manitoba, and central British Columbia
(Fig. 18). These data must be viewed with some caution,
because the BBS has limited coverage for many species
(including loons) due to the low density of routes in northern
and other remote areas. Common Loon abundance is
probably under es ti mated through the BBS due to generally
poor BBS coverage of the boreal forest.
During the Maritimes Breeding Bird Atlas
(1986–1990), Common Loons were recorded in 506 (33.1%)
of 1529 surveyed squares (10 × 10 km squares); flight less
young were recorded in 185 (12.1%) squares, and nests in 47
squares (3.1%) (Erskine 1992). Erskine (1992) indicated that
loons were less frequent in areas where the under ly ing rock
was sed i men tary (eastern New Brunswick, northern Nova
Scotia, Prince Edward Island) because of the absence or
scarcity of lakes suitable for them.
In southern Quebec, Common Loons were reported in
998 (40.5%) of 2464 atlas squares; of these records, 451
(45.2%) were of possible breeding, 350 (35.1%) of probable
breeding, and 197 (19.7%) of confirmed breeding (Alvo
1995). Most loons occur in the Laurentians, Abitibi Uplands,
and Anticosti Island, where large water bodies are abundant
(Alvo 1995). Aerial surveys conducted in 1990–1992
indicated that there were 2–16 pairs/100 km2 in the Lau ren -
tian and Abitibi areas (D. Bordage, CWS – Quebec Region,
unpubl. data). Densities of breeding pairs in Quebec were
estimated by DesGranges and Laporte (1979) to be 10 times
greater south than north of the 50th parallel in the
Laurentians and Appa la chians. In northern areas of Quebec,
loon pop u la tions are limited by the high pro por tion of lakes
lacking fish and/or having high turbidity (DesGranges 1989).
In Ontario, loons are abundant within the Canadian
Shield of the Great Lakes–St. Lawrence basin and boreal
forest regions (Dunn 1987). Within the BBS coverage area,
they reach their highest abundance in the Lake of the Woods
area (Fig. 18). Loons are now essen tially absent from the
Car o lin ian forest zone where they pre vi ously bred (Dunn
1987). During the Ontario Breeding Bird Atlas (1981–1985),
Common Loons were reported in 1007 (55%) of 1824 survey
squares. Breeding was possible in 21% of squares, probable
in 34%, and confirmed in 45%. In north east ern and central
Ontario, the highest densities of loons, deter mined from
waterfowl surveys, were in the Chapleau area
(22 pairs/100 km2) and Gogama area (21 pairs/100 km2) and
the lowest in the Sault Ste. Marie area (4 pairs/100 km2),
with an overall average density of 13 pairs/100 km2
(McNicol et al. 1987). A footnote to Table 8 gives a
summary of survey meth od ol ogy.
Loons are abundant in the area around Flin Flon,
Cranberry Portage, Snow Lake, and La Pas in Manitoba,
where lakes are underlain by limestone and were covered by
Glacial Lake Agassiz. These lakes have rel a tively high pH,
numerous islands and beach ridges, and large fish pop u la -
tions (see Yonge 1981). Yonge (1981) found an average
pop u la tion of about 100 pairs, or 1 pair/40 ha, at Hanson
Lake, Sas katch e wan (80 km west of Flin Flon), and con sid -
ered this typical of lakes in the region. In addition, large
numbers of nonbreeding loons appar ently flock in these areas
and would probably be counted on the BBS. However, loons
are notably absent from many large lakes in Sas katch e wan,
because 1) lakes are too large and shallow with excessive
wave action, lake-level fluc tu a tions, or turbidity; 2) the
limestone bedrock does not provide sites with suitable
elevation or veg e ta tion cover for nests; or 3) lakes in this
region may have poor fish stocks or fish pop u la tions inac ces -
si ble to loons (B. Koonz, Wildlife Branch, Manitoba Depart -
ment of Natural Resources, pers. commun.).
Similarly, Common Loons are absent or extremely
rare and localized in the prairie potholes of southern
Manitoba, Sas katch e wan, and Alberta (as shown by BBS;
Sauer et al. 2000) because of the shallow depth of water
bodies, poor fish stocks, and high intensity of human/agri cul -
tural activity in this area (Vogel 1997; D. Nieman, CWS –
Prairie and Northern Region, pers. commun.).
In Sas katch e wan, loons were recorded as breeding in
249 of 724 (34%) surveyed squares; breeding was possible in
16%, probable in 12%, and confirmed in 6% of squares. The
species is a “common summer resident of northern Sas katch -
e wan, south to Redberry Lake, the Yorkton region, Nickle
Lake and Moose Mountain” (Smith 1996). The Sas katch e -
wan atlas, however, was based on his tor i cal records and
some field obser va tions and is not com pa ra ble to the intense
surveys conducted over 5- to 10-year periods in some of the
other provinces.
In Alberta, most records of breeding Common Loons
were in the boreal forest and parkland; very few records were
from the grassland zone (Semenchuk 1992). During the
Breeding Bird Atlas, loons were reported in 760 of 2206
squares surveyed (34.5%) in Alberta. Breeding was recorded
in 26.7% of squares; of these, breeding was possible in
29.8%, probable in 30.3%, and confirmed in 40.0% of
squares.
In British Columbia, the highest abundance of
Common Loons, according to the BBS and breeding records,
is in the Thompson–Okanagan and Fraser plateaus and the
Fraser River basin (Campbell et al. 1990). In the Yukon,
28
Figure 17
Per cent age of Canadian Common Loon pop u la tion in different
provinces/ter ri to ries
Common Loons are most abundant in the south, where
confirmed breeding has occurred at the head of the Stewart
River, in the Chapman Lake area in central Yukon, and in
Old Crow Flats in the north. Scoby Lakes near the Coal
River in southeast Yukon had a high number of nests in June
1986 (Birds of the Yukon database, CWS Pacific and Yukon
Region, unpub. data).
The Christmas Bird Count (CBC), a volunteer
program run in North America since 1959, indicates that
most loons winter on the Atlantic, Pacific, and Gulf coasts of
the United States (Fig. 19).
4.3 Pop u la tion trends
Some evidence exists to suggest that Common Loons
have retreated from parts of their former range, par tic u larly
their southern breeding limits (McIntyre and Barr 1997). In
Ontario, loons have been extir pated south of 43°30’N
latitude (Peck and James 1983), largely because of agri cul -
ture and urban iza tion (Dunn 1987). Although most of their
historic range is occupied in the Maritimes, Erskine (1992)
estimated that loon numbers have been reduced by 33–55%
since pre-European set tle ment times.
Rel a tively few data exist on long-term trends for
Common Loon abundance or repro duc tive param e ters in
Canada. Sources of data on loon pop u la tion param e ters
include the Canadian Lakes Loon Survey (CLLS) (McNicol
et al. 1995a; http://www.bsc-eoc.org/cllsmain.html); aerial
waterfowl surveys, espe cially as part of the North American
Waterfowl Man age ment Plan joint ventures (various dates);
the BBS 1967–1998 (Dunn et al. 2000); the CBC (Sauer et
al. 1996); and Étude des Pop u la tions d’Oiseaux du Québec
(ÉPOQ) (J. Larivée and A. Cyr, l’Association québécoise des
groupes d’ornithologues, pers. commun.). In addition, a few
long-term studies have evaluated pop u la tion param e ters and
trends in specific locations, including Kejimkujik National
Park, Nova Scotia; the Lepreau area, New Brunswick; and
La Mauricie National Park, Quebec (Burgess et al. 1998a,b;
Kerekes and Masse 2000).
For the Atlantic provinces, spring heli cop ter survey
data are available for breeding loon pairs in New Brunswick,
Nova Scotia, and New found land and Labrador. Using the
data 1990–1999; no sig nif i cant trend in loon breeding
densities was observed in New Brunswick, but there was a
sig nif i cant decline in adult loon numbers in Nova Scotia (N.
Burgess, CWS – Atlantic Region, pers. commun.). In
Kejimkujik National Park, Nova Scotia, no appre cia ble trend
is apparent. Numbers of adults are unchanged, and, although
fledging success declined for a few years (Kerekes and
Masse 2000), it has recently returned to the level observed in
the 1980s, an appre cia bly lower rate (~0.3 large young per
resident pair) than the average for eastern North America
(~0.5–0.6 large young per resident pair) (J. Kerekes, CWS –
Atlantic Region, pers. commun.).
According to the latest ÉPOQ analyses (J. Larivée,
l’Association québécoise des groupes d’ornithologues, pers.
29
Figure 18
Geo graph ical dis tri bu tion and relative abundance (number of counts per 50-stop route) of Common Loons during
summer, 1982–1996, based on Breeding Bird Survey (BBS) data (Sauer et al. 2000). Green line indicates northern limit
of survey.
commun.), loon pop u la tions in Quebec were stable over the
period from 1980 to 2000. This con clu sion is sub stan ti ated
by counts of loons made during heli cop ter surveys of
breeding Black Ducks in Quebec, which indicate stable or
increas ing loon numbers (LePage and Bordage 1998; L.
Champoux, CWS – Quebec Region, pers. commun.; Fig. 20).
In Ontario, loon numbers appear to be stable or
increas ing overall, based on data from waterfowl surveys
(Ross 2002). However, analysis of temporal patterns in
Common Loon breeding pro duc tiv ity indicates a different
trend (Jeffries et al. 2003). Loon breeding success data were
collected by CWS staff or CLLS vol un teers from 292 lakes
in three CWS Acid Rain Biomonitoring Program study areas
in central Ontario (Jeffries et al. 2003) between 1987 and
1999. When the effects of lake area and pH were taken into
account, there was a sig nif i cant negative trend over this
30
Figure 20
Counts of Common Loons in Quebec, 1990–2000, during Black Duck Joint Venture heli cop ter surveys
Figure 19
Winter dis tri bu tion and abundance (number of counts per 50-stop route) of Common Loons in North America, estimated
through the Christmas Bird Count (CBC) (Sauer et al. 1996)
period in the pro por tion of observed pairs with at least one
chick estimated to have fledged. Although these results
confirmed the important influence of lake pH on loon
breeding success, temporal trends in breeding pro duc tiv ity
were similar among all lake pH classes, indi cat ing that
factors other than pH alone were involved in the decline in
breeding success. Addi tional infor ma tion, par tic u larly doc u -
men ta tion of the inter ac tions between important pop u la tion
attrib utes (e.g., demo graph ics, dispersal patterns) and acid -
ity-related and other stressors (e.g., mercury, weather, and
climate), is needed to reconcile current obser va tions of stable
or increas ing adult pop u la tions and declining breeding pro -
duc tiv ity. The analysis of CLLS data indicates that even
10-year periods may not be suf fi ciently long to allow a
confident iden ti fi ca tion of trends in loon repro duc tive param -
e ters and that there can be rather large yearly variation in
loon pro duc tiv ity.
Recent analysis of breeding survey data for all of
eastern Canada (Fig. 21) indicates an overall increas ing trend
in the number of loon pairs over the period 1990–2000, with
an overall rate of increase of 16.6% per annum (P < 0.05;
Collins 2000). Sig nif i cant increases were also found within
most indi vid ual geo graph ical strata (Stratum 2 [Eastern
boreal (New found land, southern Labrador, northeast shore of
Quebec)], 67.5% annual increase; Stratum 3 [Central boreal
(eastern Quebec boreal forest)], 78.0% annual increase; and
Stratum 4 [Western boreal (western Quebec boreal forest
plus Ontario boreal forest)], 11.9% annual increase; Fig. 21).
Only a single stratum (Stratum 1 [Atlantic highlands (Nova
Scotia, New Brunswick, southeast shore of Quebec)])
showed a sig nif i cant decreas ing pop u la tion trend (5.9%
annual decrease; Fig. 21). Overall, the average breeding
density (number of indicated breeding pairs per 100 km2) for
Common Loons in eastern Canadian surveys ranged from a
low of 6.4 in 1991 to a high of 15.4 in 1997 (Collins 2000).
Analogous data for western Canada are scarce; apart from
inci den tal counts of loons made during waterfowl surveys,
rel a tively little is known about loon pop u la tion numbers or
trends in western Canada.
Another source of data from which loon pop u la tion
trends can be derived is the BBS, although again it must be
cautioned that the BBS has lim i ta tions for mon i tor ing trends
in aquatic species such as loons. Nev er the less, all results
from this survey, whether at the national or at the ecozone
level, indicate that Canadian Common Loon pop u la tions are
stable or increas ing (Table 9; Fig. 22). For Canada overall,
there was a mar gin ally sig nif i cant increase (P < 0.15) over
the long term and a sig nif i cant increase (P < 0.05) over the
last 10 years (Table 9; Dunn et al. 2000). There was no
evidence of declining pop u la tions within any ecozone. Mar -
ginally sig nif i cant increases occurred in the Boreal Plains
ecozone (1989–1998), and a sig nif i cant increase occurred in
the Pacific Maritime ecozone from 1967 to 1998.
The CBC (Sauer et al. 1996) cannot provide trend
estimates for Common Loons, because most indi vid u als
winter offshore and are not recorded by land-based
observers. In Canada, the highest con cen tra tions of loons on
31
Figure 21
Estimated Common Loon pop u la tion trends in eastern Canada, from annual surveys of indicated breeding pairs (Collins
2000). Stratum 1 = Atlantic highlands (Nova Scotia, New Brunswick, southeast shore of Quebec); Stratum 2 = Eastern
boreal (New found land, southern Labrador, northeast shore of Quebec); Stratum 3 = Central boreal (eastern Quebec
boreal forest); Stratum 4 = Western boreal (western Quebec boreal forest plus Ontario boreal forest) (adapted from
Collins 2000).
CBCs are in western British Columbia and in southern New
Brunswick and Nova Scotia.
Loons are increas ing in some north east ern parts of the
United States where they were formerly locally extir pated
(e.g., areas in New England such as southern New
Hampshire and Vermont) and in the northwest (parts of
north east ern Wash ing ton and the Idaho Panhandle). In some
other states, pre vi ously doc u mented declines have continued
(e.g., some areas of Michigan; Evers 2000).
In summary, there is little evidence to suggest that
loon pop u la tions are generally declining in Canada.
However, available data are not suf fi ciently robust to state
this with con fi dence, espe cially given that very little
adequate pop u la tion mon i tor ing of Common Loons has been
under taken. Regional or local reduc tions in pro duc tiv ity
and/or declining breeding densities have been doc u mented in
some areas of eastern Canada.
4.4 Pop u la tion modelling
Wildlife pop u la tion modelling has become extremely
popular and sophis ti cated over the last two decades (Clobert
and Lebreton 1991; Lebreton et al. 1992; McDonald and
Caswell 1993), and there are now numerous software
programs spe cif i cally designed for modelling and deci -
sion-making (e.g., for American Black Duck Anas rubripes
man age ment: http://fisher.forestry.uga.edu/blackduck/
software.html). Matrix modelling involves complex algebra
and will be only briefly outlined here; for a full review, see
Caswell (1989) and McDonald and Caswell (1993). Many
different versions of models exist, and these may be unstruc -
tured, stage-structured, or age-structured. A well-known
age-structured model suited to many avian species is the
Leslie matrix (McDonald and Caswell 1993). Alter na tively,
rather than simply clas si fy ing indi vid u als by age,
stage-structured models allow the researcher to define clas si -
fi ca tions by many variables of bio log i cal interest, including
spatial location, social status, habitat quality, and stage of
devel op ment. Matrix models include sen si tiv ity analysis —
that is, they allow the inves ti ga tor to determine objec tively
which life history param e ters are most important from an
eco log i cal or evo lu tion ary per spec tive; field research can
then be appro pri ately focused on these param e ters
(McDonald and Caswell 1993). Matrix models can be con -
structed using the life cycle graph and include sto chas tic
variation and den sity-dependent nonlinearities necessary for
sim u la tion modelling.
Sim u la tion modelling has been carried out for many
avian species — in North America, perhaps most notably for
the Northern Spotted Owl Strix occidentalis (Franklin et al.
1996; Raphael et al. 1996) and Florida Scrub Jay
Aphelocoma coerulescens (Fitzpatrick and Woolfenden
1989), as well as for several endan gered species (see
McDonald and Caswell 1993). For long-lived species, such
32
Ta ble 9
Pop u la tion trends in dif fer ent Ca na dian ecozones de rived from the Breeding
Bird Sur vey (Dunn et al. 2000)
1967–1998 1989–1998
Ecozone TrendanbTrendanb
All of Canada 1.7** 289 5.0* 198
Boreal Shield 0.3 109 2.4 70
Atlantic Maritime 3.3 54 10.6 34
Mixedwood Plains 12.6 17 14.7 15
Boreal Plains 4.3 39 8.8** 32
Pacific Maritime 13.4* 16
Montane Cordillera 3.6 41 3.0 30
a% an nual change; ** in di cates sig nif i cant at P < 0.15; * in di cates sig nif i -
cant at P < 0.05.
bn = total number of BBS routes used to calculate trend.
Figure 22
Trends (mean percent change per year over the period 1966–1996) in Common Loon numbers estimated from Breeding
Bird Survey data (Sauer et al. 2000). Data indicate regional pop u la tion increases over most of the loon’s Canadian range.
Green line indicates northern limit of survey.
as the Common Loon, an age-structured model is most
appro pri ate and was used by Evers et al. (2001) to model the
effects of mercury on loon pop u la tions in New England.
Incor po rating the effects of envi ron men tal con tam i nant
exposure (e.g., lead sinker ingestion) into such models is
essen tially no different from examining the effects of any
den sity-independent mortality factor (e.g., effects of hunting
mortality on game bird pop u la tions; Johnson and Williams
1999).
Recent attempts have been made to model the effects
of con tam i nant stressors from the level of the indi vid ual to
the pop u la tion level for a few avian species (Walker et al.
1996). For example, Sibly et al. (2000) examined the effect
of the cyclodiene pesticide, dieldrin, on pop u la tion growth
rates in Eurasian Sparrow hawks Accipiter nisus using life
history data from two areas in Britain and were able to dem -
on strate that acute dieldrin poisoning increased the instan ta -
neous mortality rate by 0.20/year (from 0.48/year — the
“natural” mortality rate — to 0.68/year) causily a pop u la tion
decline of 20%/year (8 = 0.82/year; Scenario 1). In Scenario
2, which combined both lethal and sublethal effects of
dieldrin, a decline of 60%/year was indicated. In the latter
scenario, den sity-dependent effects (pop u la tion growth rate
increased linearly as density decreased) would function to
maintain the pop u la tion at 64% of its previous level. Sibly et
al. (2000) also asked what long-term diel drin-induced reduc -
tions in fecundity or survival could be sustained by an
increas ing pop u la tion and concluded that the pop u la tion
could withstand a halving of fecundity (from 2.07 to 1.04)
and a reduction in adult survival from 0.74 to 0.55.
Clearly, there are too many unknowns, in the case of
loons in Canada, to do the kind of analysis that Sibly et al.
(2000) have done for Eurasian Sparrow hawks in Britain. The
pro por tion of the British sparrowhawk pop u la tion having
highly elevated (>9 µg/g) levels of dieldrin in the liver could
be con fi dently estimated, because birds were being actively
sampled over many years and their dieldrin con cen tra tions
were being measured and recorded. Similar mon i tor ing for
elevated lead exposure in loons has not been under taken so
that the pro por tion of the Canadian loon “pop u la tion” having
elevated lead exposure is unknown. Even if blood lead mon i -
tor ing were being done, the data would not be useful for
deter min ing lead sinker ingestion rates, because lead sinker
poisoning is acutely toxic. Either none of a sample of loons
will have ingested a sinker, and thus all will have uniformly
low blood lead con cen tra tions, or a number of indi vid u als
will have ingested a sinker and rapidly perished, almost
certainly not being included in blood sampling surveys.
There are no confident estimates of the total number of loons
that die annually of lead sinker poisoning or of the rates of
lead sinker ingestion for any loon pop u la tion in Canada.
Evers et al. (2001) modelled the effects of dietary
mercury exposure on loons in New Hampshire using 25
years of pop u la tion data collected on 1276 adult and 955
juvenile loons and found that only 133 lakes out of more
than 700 suitable lakes were occupied by loons in New
Hampshire. One factor limiting pop u la tion expansion may be
mercury exposure. Loons using habitats where they were at
high risk for elevated mercury exposure had 15% fewer
nests, 51% fewer eggs, and 45% fewer young than those
using “low-risk” habitats. Based on three main pop u la tion
parameter estimates (annual adult survival, 95%; annual
juvenile survival, 60%; and average age at first breeding, 7
years), Evers et al. (2001) used Leslie pop u la tion matrices to
model the effects of mercury on New Hampshire loon pop u -
la tions (Fig. 23). They also used elas tic ity analysis to
simulate how pop u la tion growth rate might respond to a pro -
por tional change in a par tic u lar life history trait. This
modelling indicated that once 18% of the loon pop u la tion
was affected by mercury, 53% fewer young would survive,
33
Figure 23
Pop u la tion growth rate (lambda) versus repro duc tive success in Common Loons in New Hampshire (from Evers et al.
2001). TP = ter ri to rial pair
and the overall pop u la tion would decline by 9.5%/year
(Fig. 23). Modelling was performed using RAMAS software
(Akçakaya et al. 1999).
In order to model the response of a local or regional
loon pop u la tion to a specific envi ron men tal stressor, such as
lead sinker poisoning, at least five pop u la tion param e ters,
and the effects of the stressor on each, need to be ascer -
tained: 1) fertility (repro duc tive success), 2) the age-specific
pro por tion of breeders, 3) immi gra tion and emi gra tion
(dispersal) rates, 4) adult/juvenile survival rates, and 5) pop -
u la tion density (Clobert and Lebreton 1991).
Repro duc tive success (the average number of fledged
young per ter ri to rial pair) can be estimated based on several
studies of varying duration in Canada and the United States.
For example, the average number of chicks per ter ri to rial
pair was 0.57 (range 0.20–1.00) in La Mauricie National
Park in Quebec (Kerekes and Masse 2000), 0.54 in the
Hanson Lake area in Sas katch e wan (Yonge 1981), 0.40 in
north-central Alberta (Gingras and Paszkowski 1999), and
0.28 in Kejimkujik National Park in Nova Scotia (Kerekes et
al. 1995). In New Hampshire, an average of 68% of ter ri to -
rial pairs attempt nesting, and there were 0.52 young fledged
per ter ri to rial pair, based on a 22-year stan dard ized,
statewide database (Taylor and Vogel 2000). For northern
Michigan, Wisconsin, and Minnesota sites, repro duc tive
success ranged from 0.51 to 0.79 per ter ri to rial pair (Evers et
al. 2000).
Little infor ma tion exists on the age-specific pro por -
tion of breeding loons, even for inten sively studied sites in
New England; therefore, for modelling purposes, the prob a -
bil ity that an adult that has not bred pre vi ously will breed in
a given year must be estimated (Nur and Sydeman 1999). In
U.S. studies, age at first breeding ranged from 4 to 11 years,
with a mean of 7 (based on 32 marked loons). It is also
important to determine the pro por tion of the potential
breeding pop u la tion that are nonbreeders (Nur and Sydeman
1999). In north west ern Ontario, Croskery (1990) found that
the number of young fledged annually from 254 active ter ri -
to ries ranged from 57 to 67 (22–26%) (1983–1986), with
>80% of suc cess ful repro duc tion coming from only 76 ter ri -
to ries, indi cat ing that a large pro por tion of the breeding pop -
u la tion was typically unsuc cess ful (Croskery 1990).
Similarly, Taylor and Vogel (2000) estimated that unsuc cess -
ful ter ri to rial or nonterritorial adults may comprise up to 46%
of the summer loon pop u la tion.
Dispersal data have been collected for loons in some
U.S. sites. Dispersal distances were 1–11 km for breeding
adults and 13–96 km for juveniles; and returning adults
banded as juveniles estab lished ter ri to ries 1–64 km from
their natal lakes (Evers et al. 2000, 2001). Ter ri to rial fidelity
(another measure of immi gra tion/emi gra tion) averaged >80%
for U.S. (northern Michigan, Wisconsin, Minnesota) loons,
but varied according to whether ter ri to ries were par tial-lake,
multi-lake, or whole lake (72%, 76%, and 84% fidelity,
respec tively). The degree to which loons use different lakes
can affect their prob a bil ity of exposure to con tam i nants,
including lead sinkers, because even adjacent lakes can differ
widely in water chemistry (Piper et al. 1997) and in degree of
human use, including rec re ational angling intensity. Data on
dispersal provide infor ma tion on source–sink effects
(Pulliam 1988) and the relevance of metapopulation
dynamics (Hanski 1994), which is critical for demo graphic
modelling. For example, it is known that emi gra tion of loons
from pop u la tions in British Columbia and Montana helped
natural res to ra tion of a breeding pop u la tion in Idaho (Evers
2000). However, the degree of inter change and mixing that
occurs at different geo graph ical scales is generally not well
known.
Survival (or mortality) rates can be estimated from
recap tures (or resightings) of marked birds and recov er ies of
banded birds and can be analyzed with software such as
SURVIV or MARK (Clobert and Lebreton 1991; White and
Burnham 1999). Based on obser va tions of over 600 banded
loons in the upper Great Lakes region from 1989 to 1998,
Evers et al. (2000) estimated an annual adult mortality rate of
3–4%, which is extremely low compared with those of
almost any other bird species.
Lead sinker ingestion is extremely toxic and virtually
always results in acute mortality in loons. Sublethal effects
have not been reported and are appar ently rare (due to the
lethal nature of most ingestion incidents), but might pre dis -
pose any surviving loons to other mortality events, such as
col li sions with boats or drowning in fishing gear (Miconi et
al. 2000). Because sinker ingestion generally has an acutely
toxic effect, col lect ing data on repro duc tive param e ters, such
as numbers of young fledged per ter ri to rial pair in areas
where loons are exposed to lead, would not be par tic u larly
helpful; rather, it would be necessary to construct a matrix
pop u la tion model that included lead poisoning as a mortality
factor. To accom plish this, accurate estimates of
lead-induced mortality, as well as other causes of mortality,
are necessary. This requires accurate long-term data on adult
survival rates, which can be obtained only through long-term
surveys of banded indi vid u als. Con cur rently, com pre hen sive
records of all lead sinker (and other) mortality events would
need to be kept. If lead poisoning mortality were additive to
the natural mortality rate, then annual survival, S, would be:
S = e–(L+N)
where L is the lead sinker-induced and N the natural
instan ta neous mortality rate. Addi tional terms describ ing
mortality rates from other important anthropogenic sources
(e.g., gunshot wounds, col li sions with boats, oiling, etc.)
would then need to be incor po rated into this equation. With
current data, it is not feasible to accu rately estimate mortality
from lead sinker ingestion, or any other specific cause, in
Common Loons in Canada. To fill this infor ma tion gap,
studies to inten sively monitor mortality/survival rates in
groups of marked birds, coupled with accurate
doc u men ta tion of the relative impor tance of different causes
of death in loons in specific areas iden ti fied for research in
Canada, would be needed. Researchers should focus on
gathering the necessary pop u la tion param e ters under a few
different envi ron men tal con di tions; for example, a healthy
loon pop u la tion in an area with little or no exposure to
anthropogenic stressors (e.g., parts of north west ern Ontario)
might be compared with a pop u la tion using otherwise similar
lakes that are exposed to high rec re ational angling pressure.
Fur ther more, it may not be suf fi cient to determine overall
loon pro duc tiv ity at various study sites, because some adult
loons may con trib ute dis pro por tion ately to annual
pro duc tiv ity (Croskery 1990). These birds may need to be
iden ti fied, because if certain envi ron men tal stressors
selec tively affect these indi vid u als, sub stan tially greater
pop u la tion effects may result than if mainly nonproductive
loons were being impacted. Such infor ma tion is unavail able
34
over most of the Common Loon’s range in Canada.
Esti mating (or modelling) the influence of lead sinker
mortality on loon pop u la tions requires com pre hen sive
demo graphic studies to determine needed pop u la tion
param e ters.
If more intensive loon pop u la tion research were to be
under taken in Canada, it might be prudent to focus on areas
where long-term data on loon pro duc tiv ity and lake water
chemistry and infor ma tion on some envi ron men tal stressors
are already available: Kejimkujik National Park, Nova Scotia
(Kerekes et al. 1995; Burgess et al. 1998a,b); La Mauricie
National Park and Gatineau Park, Quebec (Lane et al. 2000);
Algoma, Sudbury, and Muskoka in Ontario (McNicol et al.
1995a,b); and some areas of Alberta (Gingras and
Paszkowski 1999). Indi vid ual loons have already been
marked in some of these areas (Lane et al. 2000), but
follow-up studies have generally not taken place. Whether
these regions provide an appro pri ate range of rec re ational
angling pressure would need to be evaluated. Areas that
expe ri ence little or no rec re ational angling would be immune
from potential impacts of lead sinker ingestion.
4.5 Matching the spatial dis tri bu tion of loons with
geo graph ical patterns of angling pressure — using
GIS to model regional effects
A com ple men tary approach to modelling pop u la tions
is to use a GIS to overlay life history data of interest (e.g.,
numbers of breeding pairs, repro duc tive success, mortality)
with infor ma tion on known physical and chemical stressors,
such as lake pH; fish mercury con cen tra tions; physical lake
attrib utes, such as surface area, depth, and turbidity; indices
of human activity, such as level of cottage devel op ment,
intensity of rec re ational angling, and level of motorboat and
jet ski use; and pertinent data on weather and fish abundance.
Rela tion ships between these various potential stressors and
loon pop u la tion param e ters could then be deter mined. Then,
by holding other stressors constant in the model, different
scenarios of increased or decreased exposure to a par tic u lar
stressor (e.g., angling pressure) and its effect on repro duc tive
success or pop u la tion growth could be simulated.
An analogous approach has recently been used to
predict improve ments in the suit abil ity of lakes to support
Common Loon and Common Merganser nesting pairs
following recovery of acidified lakes in south east ern Canada
after 2010 sulphate emission control targets are achieved
(Fig. 24; Blancher et al. 1992; McNicol 1999). In principle, a
data layer for lead sinker density could be inte grated into a
similar spatial model. If data are not available for the actual
dis tri bu tion and abundance of lead sinkers in lakes, then a
layer indi cat ing angling intensity could perhaps be used as a
surrogate, assuming a direct rela tion ship between angling
intensity and lead sinker abundance in lakes. To develop the
model, a contour map rep re sent ing possible exposure of
loons to lead via sinkers could be inter po lated and the
resulting values spatially asso ci ated with data on loon pro -
duc tiv ity in locations where such data were available.
Good pre dic tive models require a clear under stand ing
of the rela tion ships between changing stressor intensity and
pop u la tion response. Currently, such a level of under stand ing
does not exist for lead sinker dis tri bu tion or angling pressure
(or for most other potential envi ron men tal stressors) and loon
pop u la tion dynamics. Perhaps, as a first step, a GIS approach
could identify the most “at-risk” areas, where multiple
stressors overlap to create habitats in which loons are most
likely to be adversely affected. For example, geo-referenced
data on rec re ational angling intensity could be overlain with
data on lake acidity, fish mercury con cen tra tions, and other
appro pri ate stressors to which loons are sus cep ti ble, to
identify envi ron ments where loons are most likely to be
exposed to hazardous con di tions. Field research to study
loon pop u la tion dynamics could then be directed to those
locations.
35
Figure 24
Predicted changes in the pro por tion of habitat suitable across eastern Canada for nesting piscivorous birds (Common
Loon plus Common Merganser) between 1982 and 2010, after current sulphate emission control targets are achieved
(McNicol 1999)
4.6 Summary and pri or i ties for future research
Sub stan tially improved estimates of critical model
param e ters are needed before the pop u la tion effects of
lead-induced mortality in Common Loons can be assessed
with any con fi dence. To address this issue, long-term mon i -
tor ing to determine essential demo graphic data from a few
selected study pop u la tions in Canada, rep re sent ing a range of
differing scenarios of exposure to lead sinkers and other
envi ron men tal stressors, would have to be under taken.
Following marked indi vid u als through time is essential to
derive accurate pop u la tion param e ters for different
subpopulations. Once such needed data were forth com ing,
matrix and metapopulation modelling could be carried out
using software such as RAMAS (see Akçakaya et al. 1999).
Alter na tively, accurate loon abundance and pro duc tiv ity
data, once gathered and mapped, could be overlain, in a GIS,
with accurate measures of rec re ational angling intensity, to
determine if negative rela tion ships exist over time between
sinker use and loon abundance or pro duc tiv ity. It is for
wildlife managers to decide whether such expensive
long-term studies are required before reg u la tory or other
controls on the man u fac ture, sale, or use of lead sinkers and
jigs are under taken, con sid er ing that lead sinker poisoning is
a clearly doc u mented, major (and pre vent able) cause of
mortality for breeding loons in south east ern Canada, where
rec re ational angling activity is rel a tively intense (section 3).
Important analyses that are needed in order to con fi -
dently analyze the pop u la tion effects of lead sinker poisoning
in loons includes:
•life history data for loons in Canada, including the most
“at-risk” loon subpopulations, using indi vid u ally marked
birds to derive important pop u la tion param e ters;
•DNA analyses to better define “pop u la tions” and to better
under stand source–sink effects and metapopulation
structure for Common Loons in Canada; and
•inte gra tion of multiple envi ron men tal stressors into a
large-scale spatial analysis using GIS.
36
5. Ini tia tives to reduce the impacts of lead sinkers and
jigs on wildlife and the envi ron ment
5.1 Devel op ment of lead-free fishing sinkers and jigs
Numerous nontoxic alter na tive materials exist for the
man u fac ture of fishing sinkers and jigs, including tin, steel,
bismuth, tungsten, rubber, and clay. Each of these alter na tive
materials differs with respect to the types of uses for which it
is appro pri ate, based on various factors, including mal lea bil -
ity and density. Steel, tin, and bismuth sinkers were among
the first lead-free alter na tive fishing weights available in the
United States and Canada; however, a wider variety of
nontoxic sinkers and jigs is now being produced. Most of the
nontoxic sinker man u fac tur ers are located in the United
States, but there are several companies in Canada that have
indicated that they produce nonlead sinkers and jigs
(Table 10).
Tin, steel, and bismuth sinkers are perhaps the most
common alter na tives to lead; bismuth is also a rel a tively
common alter na tive for jig and spinnerbait pro duc tion. Zinc
and brass sinkers are also available; however, metallic forms
of these materials are known to be toxic to waterfowl and
other birds, although they are less toxic than lead (Grandy et
al. 1968; U.S. EPA 1994; Zdziarski et al. 1994). A limited
selection of alter na tive sinkers and jigs is currently available
through large retail chain stores and tackle and sporting
goods stores in Canada.
Many of the available alter na tive products are
currently more expensive than lead, as a result of higher
costs of the raw materials and more com pli cated man u fac tur -
ing processes. Table 11 sum ma rizes the approx i mate retail
prices of various fishing weights and gives the estimated cost
that Canadian anglers may face when pur chas ing lead-free
products.
5.2 Reg u la tory and awareness ini tia tives in Canada
In 1997, Envi ron ment Canada and Parks Canada, in a
parallel reg u la tory ini tia tive, pro hib ited the pos ses sion of
lead fishing sinkers and lead jigs weighing less than 50 g by
anglers fishing in National Wildlife Areas and National
Parks, under the Canada Wildlife Act and the National Parks
Act, respec tively (Canada Gazette 1997b; Parks Canada
1997). These two reg u la tions are of limited geo graphic scope
(<3% of Canada’s land mass; Fig. 6) and are antic i pated to
affect only about 50 000 out of the estimated 5.5 million rec -
re ational anglers in Canada.
Since 1995, various gov ern men tal and
nongovernmental orga ni za tions have conducted lead sinker
and jig col lec tion and exchange programs, have dis trib uted
lit er a ture on the toxic effects of lead tackle, and have
promoted the voluntary use of alter na tive materials. Envi ron -
ment Canada supported several of the early sinker exchanges
with funding through its Great Lakes 2000 program. The
Ontario Ministry of the Envi ron ment’s Bay of Quinte
Remedial Action Plan’s “Take a little lead out” program was
a pilot project upon which other orga ni za tions have modelled
their own sinker and jig exchanges. Several cottage asso ci a -
tions have declared their lakes to be “lead-free.” In addition,
Parks Canada has conducted edu ca tional campaigns and
estab lished lead tackle col lec tion and exchange sites at many
of their National Parks.
In spring 1999, a Private Members’ Bill (C-403)
request ing Envi ron ment Canada to use the Canadian Envi -
ron men tal Pro tec tion Act to ban the import, man u fac ture,
sale, offer for sale, and use of lead fishing sinkers or jigs
weighing less than 50 g nation wide was tabled for dis cus sion
in the House of Commons (Bonwick 1999), reit er at ing the
rec om men da tion pre vi ously made by the Canadian House of
Commons Standing Committee on Envi ron ment and Sus tain -
able Devel op ment (Caccia 1995). In response to this Bill,
Envi ron ment Canada agreed to develop a national com mu ni -
ca tions strategy and to work with partners to establish a
voluntary coop er a tive lead sinker phaseout program founded
on education and public awareness. As part of this strategy,
Envi ron ment Canada has developed infor ma tion items,
including a pamphlet and a national web site
(http://www.cws-scf.ec.gc.ca/fishing/open_e.html),
providing the public with infor ma tion about the negative
effects of lead sinkers and jigs and about various lead-free
alter na tives.
Little infor ma tion is available on the level of com pli -
ance with the 1997 reg u la tion banning lead sinkers and jigs
in National Parks and National Wildlife Areas. However,
com pli ance within Canada’s National Parks is thought to be
high because of the outreach efforts within the parks and the
require ment to purchase a separate angling permit to fish
within park bound aries. The large number of anglers in
Canada (5.5 million or about 1 in 5 Canadians), coupled with
the rel a tively large pro por tion of the sinker and jig market
arising from the home pro duc tion of lead fishing sinkers and
jigs, provides con sid er able obstacles for user-based pro hi bi -
tions. Results of a mini-survey of principal stake holders
37
38
Ta ble 10
Man u fac turers of nonlead fish ing weights
Com pany Lo ca tion Type of fish ing weight
Canada
D&D Lures Windsor, Ontario Bismuth and tin sinkers and jigs
JackFish Lures Non-Toxic Tackle Co. Edmonton, Alberta Bismuth sinkers, jigs, and spinner baits
Jr’s Environmental Friendly Clay Sinkers Collingwood, Ontario Clay sinkers
Lucky Strike Bait Works Peterborough, Ontario Tin sinkers and bismuth jigs
Sourdough Bay Fishing Supplies Medicine Hat, Alberta Bismuth sinkers and jigs
Tucker Tackle Ailsa Craig, Ontario Bismuth sinkers
United States
Belvoirdale/Dinsmores Wyncote, Pennsylvania Tin sinkers
BIO-CAST Fruita, Colorado Ceramic weights
Bullet Weights Alda, Nebraska Steel and tin sinkers
Du-Co Ceramics Saxonburg, Pennsylvania Ceramic sinkers
Jadico Camdenton, Missouri Bismuth jigs
Loon Outdoors Boise, Idaho Putty sinkers
Luhr-Jensen and Sons Inc. Hood River, Oregon Rubber sinkers
ORVIS Company Roanoke, Virginia Tungsten beads, putty weights
Owner Hooks VonKarman, California Bismuth sinkers and jigs
SafeCasters Pasco, Washington Granite sinkers
Water Gremlin White Bear Lake, Minnesota Tin/plastic composite/steel resin sinkers
Britain
Dinsmores Walsall, U.K. Tin sinkers
Sweden
Eco Weight Stockholm, Sweden Magnetite/concrete sinkers
Ta ble 11
Es ti mated con sumer costs as so ci ated with the use of lead and al ter na tive sinker prod ucts for sport fish ing in Canadaa
Weight type
(size)
Ap prox i mate
av er age price
per lead
weightb ($)
Ap prox i mate
av er age price
per lead-free
weightc ($)
Av er age yearly
ex pen di ture
per an glerd ($) Av er age in crease
per an gler per
year ($)
In crease in
yearly an gling
sup plies bud get
(%)e
lead lead-free
Split shot sinkers
(assortment) 0.03 0.04 (tin) 0.42 0.56 0.14 0.3
(# 5) 0.05 0.17 (tin) 0.70 2.38 1.68 3.6
(# 7) 0.04 0.11 (tin) 0.56 1.54 0.98 2.1
Bell sinkers
(¼ ounce) 0.22 0.39 (bis muth) 3.08 5.46 2.38 5.0
Painted jigs
(¼ ounce) 0.54 0.58 (bis muth) 3.78 4.06 0.28 0.7
(d ounce) 0.47 0.58 (bis muth) 3.29 4.06 0.77 1.8
aWhere di rect com par i sons were pos si ble in large re tail stores.
b Retail price in Canadian dollars.
cIn addition to the retail prices listed above, steel bass casters were available in large retail chain stores and sold for
about $0.18 per sinker. Current retail prices for other alter na tive fishing weights were not available; however,
pro mo tional materials suggest that weights made of clay, steel, and rubber fall within the range of prices listed above
for tin and bismuth.
d Based on an estimated average of 14 sinkers and 7 jigs purchased per angler per year.
e Percent increase in fishing supplies budget of $42.00 per year. The average angler purchases about 14 sinkers per
year, at a total current cost of about $3.25 (Scheuhammer and Norris 1995). Based on retail prices of common types
of weights, the average angler may be expected to spend an addi tional $2.00 per year to use nonlead fishing weights.
regarding awareness of the issue and control options
supported an approach coupling edu ca tional programs with
national reg u la tion (Twiss and Thomas 1998). Limited edu -
ca tional ini tia tives have already been developed and imple -
mented by Envi ron ment Canada, including a Hin ter land
Who’s Who pub li ca tion on lead poisoning (CWS 1996), a
pamphlet for dis tri bu tion at outdoor shows, as well as
support for some of the Province of Ontario’s sinker
exchange programs. However, efforts have been limited, and
the majority of anglers continue to use lead.
5.3 Reg u la tory and awareness ini tia tives in other
countries
In 1987, the United Kingdom banned lead fishing
sinkers weighing less than 28.35 g (1 ounce) because of
wide spread mortality of swans from ingestion of lead sinkers
(Birkhead 1982, 1983; Gov ern ment of the United Kingdom
1986).
The U.S. Fish and Wildlife Service has banned the
use of lead sinkers and jigs weighing less than 28.35 g (1
ounce) in three National Wildlife Refuges — namely, Red
Rock Lakes, Montana; National Elk Refuge, Wyoming; and
Seney, Michigan — under the National Wildlife Refuge
System Admin is tra tion Act and has also moved to create
lead-free areas at 13 addi tional wildlife refuges in nine states
where loons and anglers coexist. In addition, the U.S.
National Parks Service, under the National Park Services
Act, has banned the use of lead sinkers and jigs weighing less
than 28.35 g (1 ounce) in Yel low stone National Park,
Wyoming.
In 1994, the U.S. EPA published, in the Federal
Register, a proposed rule under the Toxic Sub stances Control
Act to prohibit the man u fac ture, pro cess ing, and sale, within
the United States, of sinkers con tain ing lead, zinc, or brass
that are 2.54 cm (1 inch) or less in any dimension (U.S. EPA
1994). The reg u la tion as initially drafted was not enacted,
because many states and angling groups, including the
American Sportfishing Asso ci a tion, argued that there was
insuf fi cient evidence to warrant a national ban on lead
fishing sinkers. The American Sportfishing Asso ci a tion,
among others, rec om mended that regional measures be taken
to address this issue — spe cif i cally, that the U.S. EPA and
U.S. Fish and Wildlife Service evaluate the extent of the
problem nation wide, pro mul gate reg u la tions in areas where
there was evidence of a threat, pursue reg u la tions in National
Parks and National Wildlife Refuges where a problem has
been doc u mented, and initiate edu ca tional programs to
inform people about the dangers asso ci ated with improper
in-home pro duc tion of these products.
During the dis cus sion of the U.S. EPA’s proposal to
ban lead fishing sinkers and jigs, the Envi ron men tal Defense
Fund suggested that there was a potential risk to human
health from the exposure to lead fumes during home man u -
fac tur ing of sinkers and from lead ingestion as a result of
biting split shot sinkers to crimp them onto fishing lines
(U.S. EPA 1994). It was estimated that 875 tonnes of lead
may be used annually in the home pro duc tion of fishing
weights in the United States. In the United States, over
40 cases of lead toxicosis in humans as a result of home pro -
duc tion and use of lead sinkers have occurred in New York,
New Hampshire, North Carolina, and Iowa. In New York
state, seven cases of high lead exposure from sinker
pro duc tion were reported between 1988 and 1993. Blood
lead levels in all seven indi vid u als exceeded 25 µg/dL, with
three indi vid u als having blood lead levels exceeding 60
µg/dL, a level that typically causes notice able symptoms of
lead poisoning in adults (U.S. EPA 1994). Three small
children in New Hampshire were exposed in a home where
lead sinkers were made and had blood lead con cen tra tions
ranging between 27 and 53 µg/dL. Adult family members
producing the lead sinkers and cleaning the work areas also
had elevated blood lead con cen tra tions. Following transfer of
home ownership, the sub se quent family’s three children also
expe ri enced high lead exposure, with blood lead levels
ranging between 29 and 42 µg/dL (U.S. EPA 1994). In North
Carolina, an outdoor cauldron where lead was melted for
sinker pro duc tion resulted in severe con tam i na tion (450 000
µg/g) of soils in the area. U.S. EPA guide lines recommend
that children not be allowed access to areas with soil lead
levels exceeding 2000 µg/g. Soil lead levels in this instance
were more than 200 times the allowable level, and lead levels
in dust on outdoor patio areas around the home where the pot
was situated were roughly 50 times the level allowed
following lead paint abatement. At least 26 children and
adults were exposed to lead at this sinker pro duc tion site
(U.S. EPA 1994). In Iowa, two children were found to have
elevated blood lead levels asso ci ated with biting lead split
shot to attach it to fishing line (New Hampshire Depart ment
of Fish and Game 1998). In the published medical lit er a ture,
one case of lead poisoning from sinker ingestion was
reported in an 8-year-old child from Ohio. The boy had an
elevated blood lead level of 2.6 µmol/L (~54 µg/dL)
following ingestion of 20–25 lead sinkers (Mowad et al.
1998). Following removal of the sinkers and chelation
therapy, blood lead levels returned to normal.
It has been argued that human exposure to lead from
the home pro duc tion of fishing sinkers and jigs is an issue
only if lead is handled or used improp erly; however,
concerns have been raised about the quality of infor ma tion
available with home sinker pro duc tion kits. The Envi ron -
men tal Defense Fund argues that safety infor ma tion provided
with do-it-yourself kits generally warns of the risk of burning
when in contact with hot objects, but only rarely indicates
health risks asso ci ated with lead or the need to take pre ven ta -
tive pre cau tions that in an indus trial setting would be
mandated by law (U.S. EPA 1994). We are unaware of any
Canadian studies of lead exposure in people through the
home pro duc tion of sinkers and jigs; however, Health
Canada has been informed of the cases ref er enced in the
present report.
In the wake of the debate over the U.S. EPA’s
proposal to ban lead fishing sinkers and jigs, and following
the rec om men da tions for regional action, a few north east ern
states developed coop er a tive outreach programs and pursued
reg u la tory measures within their juris dic tions to address the
concerns asso ci ated with lead fishing sinkers and jigs.
The New Hampshire Depart ment of Fish and Game
ratified a state reg u la tion in July 1998 that prohibits the use
of lead sinkers and jigs weighing 28.35 g (1 ounce) or less in
all fresh wa ter lakes and ponds statewide beginning 1 January
2000 (State of New Hampshire 1998). This action was taken
to insure the Common Loon’s continued success in the state.
The New Hampshire Depart ment of Fish and Game, in coop -
er a tion with the U.S. Fish and Wildlife Service and the New
Hampshire Loon Pres er va tion Committee, launched a series
39
of com mu ni ca tion and edu ca tional ini tia tives to urge anglers
to switch to lead-free sinkers and jigs.
Maine will prohibit the sale of lead sinkers and jigs
weighing 14.2 g (½ ounce) or less beginning in the year 2002
(State of Maine 1999) and in the meantime is con duct ing an
edu ca tional campaign to inform anglers of the hazards of
lead sinkers and has insti tuted sinker exchange programs.
Mas sa chu setts has insti tuted state reg u la tions pro hib -
it ing the use of lead fishing gear on the small number of
lakes where loons are known to nest (M. Tisa, Mas sa chu setts
Division of Fisheries and Wildlife, pers. commun.).
In February 1999, a bill (S02592) was intro duced in
the New York leg is la ture to amend the envi ron men tal con -
ser va tion law to prohibit the sale and use of lead sinkers.
This bill was recently passed by the state leg is la ture, and
New York will prohibit the sale of most lead fishing sinkers
by 2004. The measure also seeks to end the hazardous
practice of biting down on lead split shot weights to affix the
sinker on fishing line.
In March 1999, a bill was intro duced in Minnesota to
authorize grants to develop alter na tives to lead fishing
sinkers and lead jigs (Minnesota House of Rep re sen ta tives
1999). The bill was read and forwarded to the Envi ron men tal
and Natural Resources Policy Committee for dis cus sion. A
coop er a tive education campaign group com pris ing wildlife
research ers, rehabilitators, vet er i nar i ans, and man u fac tur ers
and retailers of lead-free tackle has been estab lished (MOEA
1999). A similar coop er a tive education and sinker exchange
program is ongoing in Vermont (M. Pokras, Tufts School of
Vet er i nary Medicine, pers. commun.).
At the federal level, the U.S. Fish and Wildlife
Service is currently con sid er ing a proposed 2-year phase-in
on a ban of lead sinkers and jigs in National Wildlife
Refuges across the country where loons and Trumpeter
Swans breed (L. Morse, U.S. Fish and Wildlife Service, pers.
commun.)
In Sweden, research and awareness programs began
in the early 1990s in coop er a tion with the Swedish Anglers’
Asso ci a tion and the National Chemicals Inspec tor ate to
encourage the use of lead-free fishing weights (OECD 1999).
A study of the dis so lu tion of lead weights lost when fishing
was launched by the National Chemicals Inspec tor ate in
1994, and a policy was estab lished to phase out the use of
lead; however, it is believed that the use of lead sinkers for
angling is probably the same as when the policy for phaseout
was estab lished, as there is a lack of com pet i tive alter na tives
on the market. In 1999, the National Chemicals Inspec tor ate
also launched a campaign aimed at min i miz ing the use of
certain sinkers for salmon fishing during spring and autumn
in fast-flowing water, as this kind of fishing is con sid ered to
result in the highest losses of lead fishing weights. The
National Chemicals Inspec tor ate continues to work with
stake holders to encourage a phaseout of lead fishing weights
in Sweden.
The 1996 OECD Dec la ra tion on Risk Reduction for
Lead (OECD 1996) included a rec om men da tion that member
countries restrict the use of lead shot in wetlands and
promote the use of alter na tives to lead sinkers in shallow
waters.
5.4 Summary
•Numerous viable alter na tive materials exist for use in the
pro duc tion of fishing sinkers and jigs, including tin, steel,
bismuth, tungsten, rubber, ceramic, and clay. Tin, steel,
and bismuth sinkers and bismuth jigs are the most readily
available alter na tives in Canada.
•Many of the alter na tive products on the market are
currently more expensive than lead, due to a higher price
of the raw materials and more difficult man u fac tur ing
processes. Based on available direct retail price
com par i sons of common types of fishing weights, the
average angler is estimated to spend up to an addi tional
$2.00 annually to buy nonlead sinker and jig products.
•Envi ron ment Canada and Parks Canada pro hib ited the
pos ses sion of lead fishing sinkers/jigs weighing less than
50 g by anglers fishing in National Wildlife Areas and
National Parks, under the Canada Wildlife Act and the
National Parks Act, respec tively, in 1997. These two
reg u la tions are of limited geo graphic scope (<3% of
Canada’s land mass) and are antic i pated to affect only
50 000 of the estimated 5.5 million rec re ational anglers in
Canada.
•In 1987, Britain banned the use of lead fishing sinkers
weighing less than 28.35 g.
•The U.S. Fish and Wildlife Service banned the use of lead
sinkers and jigs in three National Wildlife Refuges and in
Yel low stone National Park. The states of New
Hampshire, Maine, and New York have ratified statewide
reg u la tions beginning in 2000, 2002, and 2004,
respec tively.
40
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