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Reducing sea turtle bycatch in trawl nets: A history of NMFS turtle excluder device (TED) research


Abstract and Figures

Thirty-six years ago, NOAA’s National Marine Fisheries Service began research on how to reduce mortality of sea turtles, Chelonioidea, in shrimp trawls. As a result of efforts of NMFS and many stakeholders, including domestic and foreign fishermen, environmentalists, Sea Grant agents, and government agencies, many trawl fisheries around the world use a version of the turtle excluder device (TED). This article chronicles the contributions of NMFS to this effort, much of which occurred at the NMFS Mississippi Laboratories in Pascagoula. Specifically, it summarizes the impetus for and results of major developments and little known events in the TED research and discusses how these influenced the course of subsequent research.
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26 Marine Fisheries Review
Sea turtle, Chelonioidea, bycatch
became a Federal management issue for
the U.S. southeast shrimp trawl shery
in the 1970’s after the listing of all seven
sea turtle species under the Endangered
Species Act (ESA). Although ve spe-
cies of sea turtle may encounter shrimp
trawls in U.S. waters, those of most con-
cern are the loggerhead, Caretta caretta,
and Kemp’s ridley, Lepidochelys kempii.
The loggerhead is the sea turtle most
often captured by U.S. shrimp trawls.
At the beginning of the National Marine
Fisheries Service (NMFS), NOAA,
research program, the Kemp’s ridley
was considered the most endangered
sea turtle, because it nests on only
one beach, Rancho Nuevo, Mexico,
Reducing Sea Turtle Bycatch in Trawl Nets:
A History of NMFS Turtle Excluder Device (TED) Research
Lekelia D. Jenkins is with the School of Marine
and Environmental Affairs, University of Wash-
ington, 3707 Brooklyn Ave. N.E., Seattle, WA
98105 ( Mention of trade names
or commercial rms does not imply endorse-
ment by the National Marine Fisheries Service,
ABSTRACT—Thirty-six years ago, NOAA’s
National Marine Fisheries Service began
research on how to reduce mortality of sea
turtles, Chelonioidea, in shrimp trawls. As
a result of efforts of NMFS and many stake-
holders, including domestic and foreign sh-
ermen, environmentalists, Sea Grant agents,
and government agencies, many trawl sh-
eries around the world use a version of the
turtle excluder device (TED). This article
chronicles the contributions of NMFS to this
effort, much of which occurred at the NMFS
Mississippi Laboratories in Pascagoula.
Specically, it summarizes the impetus for
and results of major developments and little
known events in the TED research and dis-
cusses how these inuenced the course of
subsequent research.
and at one time had a nesting female
population of only 300 individuals
(National Research Council, 1990; Lutz
and Musick, 1997; Lutz et al., 2003).
NMFS and the U.S Fish and Wildlife
Service (FWS) share responsibility for
protecting sea turtles, with NMFS being
responsible for protection at sea and the
FWS being responsible for protection on
land, such as protecting nesting females,
eggs, and hatchlings.
To conserve sea turtles, people have
taken measures to protect them, par-
ticularly as hatchlings and adults. Beach
monitors relocate and place protective
barriers around nests. Municipalities
have encouraged or mandated that resi-
dents regulate light use and beach trafc.
With limited success, some conservation
and management groups have attempted
captive breeding, articial imprinting of
hatchlings on new nesting beaches, and
headstarting (the captive rearing and
release of turtles once they are beyond
the size of most natural predation) (Na-
tional Research Council, 1990; Lutz and
Musick, 1997; Lutz et al., 2003).
However, studies on the reproductive
value of different life stages of log-
gerhead sea turtles reveal that recovery
of these populations cannot occur with
protection of eggs and hatchlings alone.
The most reproductively valuable life-
stages are subadults and adults, which
are the lifestages most impacted as
bycatch (Crouse et al., 1987). Thus is it
critical to reduce sea turtle mortality in
shrimp trawls.
Shrimp and sea turtles often share
the same aquatic habitat—including
coastal waters along the southeastern
United States—so shrimpers have likely
encountered sea turtles since the begin-
ning of the U.S. shrimp trawl shery
in 1913. This shery involves pulling
a net behind a boat. With advances in
shing technology, such as more power-
ful engines and winches to haul the net,
shrimpers began using larger nets and
pulling them for longer periods of time.
Presently, shrimpers typically tow their
nets underwater for 2–3 h at a time. Sea
turtles encountering a net might attempt
to swim away from it and are often en-
trained. If unable to surface to breathe,
turtles can drown during the long tow
time (National Research Council, 1990).
To address the problem of sea turtle
bycatch in trawls, it is essential to
understand the shing process and the
shing gear used. During the shrimp
shing process the outriggers, which
are stored upright, are lowered over the
water (Fig. 1). Attached to each outrig-
ger are one or two nets typically 30–50
ft in headrope length (Fig. 2). Each net
is equipped with a pair of large rect-
angular wooden doors that are 3–10 ft
long. When lowered into the water, they
slide on their edge along the seabed. The
doors are rigged with chains to pull at
an angle so that the force of the water
pushes them apart and spreads the net
open between them.
For each door, attached between the
door and ahead of the net is a tickler
chain. This looped length of chain drags
along the seabed, startling shrimp off the
bottom so that they can be captured by
the net. A leadline, also known as a foo t -
rope, is the weighted line that extends
between the doors along the bottom of
the net and helps to keep the net close
to the seabed. The corkline, oatline,
or headrope is attached to the top of the
net and is xed with varying numbers of
oats. The oats and weights help deter-
mine the shape of the net in the water.
74(2) 27
Figure 1.—Shrimp trawl boat (Source: Maril, 1983).
The shape of the net is also affected
by how it is sewn together, and about six
different types of net designs are used in
the U.S. shrimp trawl shery. The seams
of the net, where the top net is sewn to
the bottom net, are called the wings. The
entrance of the net is called the mouth.
The net tapers back from the mouth to
form a funnel, and the narrow part of the
funnel is referred to as the throat. At the
back of the net is the net bag or codend,
where the captured shrimp are collected.
Attached to the codend is the lazy line
that allows the back of the net to be
swung onboard for emptying (Maril,
1983; 1995; Maiolo, 2004).
This paper chronicles the research
that the NMFS began 36 years ago on re-
ducing mortality of sea turtles in shrimp
trawls. As a result of the combined
efforts of NMFS and many stakehold-
ers—including domestic and foreign
fishermen, environmentalists, Sea
Grant agents, and government agen-
cies—this extended community invent-
ed and continues to improve the turtle
excluder device (TED). The notable
contributions of members of this com-
munity, including shrimpers and Sea
Grant agents, far exceeds the capacity
of one paper, so this article focuses on
the contributions of NMFS to this effort,
much of which occurred at the NMFS
Mississippi Laboratories in Pascagoula
(Fig. 3). Specically, it summarizes the
impetus for and results of major NMFS
developments and little known events
in the TED research and discusses how
these inuenced the course of subse-
quent NMFS research.
Barrier Devices
The effort to invent a device to reduce
sea turtle bycatch in trawls began in
1976, but it was linked to events that
took place in 1973 and 1974. During
those years, while observing the op-
eration of various experimental trawl
nets, NMFS serendipitously recorded
three sea turtles encountering the trawl
net. One of these trawls was a separa-
tor trawl, a type of net that has a large
mesh panel that directed large objects
out of a hole in the net while allowing
small objects like shrimp to proceed into
the net bag (Fig. 4). The turtle became
entangled by its scutes and ippers and
became trapped in the exclusion chute
(Ogren et al., 1977). The video of these
encounters laid the foundation for the
initial course of research NMFS pursued
in 1976, when NMFS began researching
gear modications that would reduce
sea turtle mortality in shrimp trawls. At
the beginning of its research program,
NMFS consulted with sea turtle special-
ists Archie Carr and Larry Ogren. Based
28 Marine Fisheries Review
Figure 2. —Shrimp trawl net (Source: Maiolo, 2004).
on the video, the turtle specialists were
concerned that if a sea turtle entered
the trawl net, its marginal scutes might
become entangled in the mesh. For this
reason, NMFS initially pursued a barrier
panel to prevent the capture of sea turtles
by barring their entrance to the net.
Fieldwork on the gear began in
1978, with limited collaboration with
the Southeastern Fisheries Association
and the Texas Shrimp Association to
facilitate the use of commercial shing
vessels to conduct sea turtle population
studies and to test gear. NMFS devel-
oped two panel designs. One design was
called the “forward barrier,” which con-
sisted of a panel of webbing attached to
and sloping forward from the headrope
down to a bottom-line that ran between
the trawl doors. This design can be lik-
ened in appearance and function to the
cowcatchers placed on locomotives. Un-
fortunately, turtles were able to go under
the bottom-line and into the trawl. Also,
some shing conditions altered the trawl
congurations, causing the bottom-line
of the barrier to touch the seaoor, stim-
ulating shrimp ahead of the trawl and
allowing their escape. In 1978, NMFS
abandoned the forward barrier, because
it only reduced turtle capture by 30%
and had a large (38–53%) shrimp loss.
In 1979, gear specialists modied the
forward barrier design, resulting in the
“reverse barrier” (Fig. 5). In this design,
the webbing panel attached to the head-
rope and sloped backwards from it to
the footrope. The best reverse barrier
design reduced turtle capture by 79%
and shrimp capture by 15–30%. Unfor-
tunately, the reverse barrier increased
the drag on the trawl, causing it to lift
up like the wing of a plane and resulted
in the loss of shrimp. NMFS attempted
to correct this problem by adding weight
to the footrope, but the shrimpers on
the cooperative vessels testing the gear
objected to this as it made the trawl more
difficult to use. NMFS tried various
other rigging techniques to correct the
problems with the reverse barrier with
limited success.
In 1981, NMFS abandoned the
reverse barrier device because of its
high rate of shrimp loss and complex
design. The device also became easily
clogged with debris that caused the
trawl to become deformed, resulting
in the capture of turtles and the loss of
shrimp. In addition, the device required
custom tting to the net, thus greatly
restricting subsequent alterations to the
trawl dimensions. For example, in order
to sh effectively for different species
of shrimp, shrimpers commonly alter the
height of the trawl mouth with oats, but
the custom tted reverse barrier would
inhibit such alterations.
In 1980, the University of Geor-
gia, Marine Extension Service (UGA
MAREX) sent NMFS photos of a
“jellyball shooter” and suggested a
similar approach could work for ex-
74(2) 29
Figure 4.—Separator trawl with entrained sea turtle (Source: Ogren et al., 1977).
Figure 3.—Timeline of major events in NMFS sea turtle bycatch reduction research.
30 Marine Fisheries Review
Figure 5.—Reverse barrier (Source: J. Watson. 1980. Milestone report: sea turtle excluder trawl project. NMFS, SEFC, Pascagoula
Laboratory, Miss. [Available from Jenkins.]).
cluding turtles. The jellyball shooter
had been used for decades, especially
by shrimpers in South Carolina and
Georgia, when cannonball jellyfish,
Stomolophus meleagris, are so dense
that shrimping could not otherwise
occur. The jellyball shooter consists
of a grid that is placed in the neck of
the trawl to block large objects from
entering the net bag and directs them
out of a hole cut in the net.
Based on these photographs, John
Watson, then head of the NMFS Sea
Turtle Excluder Trawl Project, and
Eddie Toomer, a contract vessel captain
from Winter Haven, Fla., independently
and simultaneously conceived of plac-
ing the grid within a frame. Watson
constructed his version from fragile
PVC and Toomer constructed his from
heavy steel. Though Toomer’s original
model was too heavy and Watson’s too
fragile to be practical, NMFS drew
ideas from both to apply to a new
design. NMFS called the resulting
prototype the turtle excluder device
(TED) (Fig. 6).
The original prototype resulting from
these conceptual models was designed
to exclude large loggerhead turtles. The
frame was slightly more than 1 cu yd and
weighed about 97 lb. A grid was slanted
45° between a front and back oval hoop.
The grid bars were spaced six inches
apart and the device had a 3-ft square
door on the bottom. The NMFS TED
excluded 89% of the turtles that entered
the net and had no statistically signi-
cant loss of shrimp. NMFS developed a
top-opening TED as a result of divers’
observations that turtles had difculty
escaping out of the bottom-opening door
and attempted to escape upwards. This
top-opening TED increased the turtle
exclusion rate to 97%.
To reduce shrimp loss, NMFS de-
veloped a device called an accelerator
funnel. This tube of webbing functioned
by accelerating the water through the
TED, thus carrying more shrimp into the
codend. The result was a 7% increase in
shrimp catch in comparison to a trawl
without a TED.
One of the research objectives for
1981 was to determine if there was a
difference in shrimp catch with TED’s
on major shrimping grounds. After test-
ing the NMFS TED against a standard
trawl net in South Carolina, Georgia,
Florida, Mississippi, Alabama, Loui-
siana, and Texas, NMFS determined
there was either no statistical difference
or an increase in shrimp retention when
using TED’s.
In 1982, hoping to increase TED
adoption, NMFS reduced the size of the
NMFS TED to exactly 1 cu yd. Observer
data on size of the most commonly
caught turtle species suggested that the
TED could be smaller with no reduc-
tion in turtle release efciency. NMFS
reduced the size of the TED, so it would
t the smaller twin trawls common in the
Gulf of Mexico shery. Also, the size
reduction allowed for easier handling
and storage. During testing, this TED
had a statistically insignicant increase
in shrimp catch.
In 1983, to make the TED even
more appealing to shrimpers, NMFS
Figure 6.—The NMFS TED (Source:
NMFS, SEFC, Pascagoula Labora-
tory, Miss. [Available from Jenkins.]).
74(2) 31
modied not only the device but also
its name. NMFS ofcially renamed the
“turtle excluder device” the “trawling
efficiency device” in an attempt to
market its ability to exclude trash that
could damage the net and to reduce
nsh bycatch with a hummer wire
that vibrated, encouraging sh to exit
the net.
NMFS also explored the use of
alternative lighter materials for TED
construction. With the help of the Naval
Surface Weapons Center’s Plastics
Laboratory, NMFS created two new
prototypes: a plastic NMFS TED and
a berglass NMFS TED. The plastic
NMFS TED was too exible and could
not withstand minimum loads. The
berglass NMFS TED was stable but
not durable, so NMFS modied it to
increase durability. NMFS also created
a collapsible berglass TED. Testing
showed that these prototypes were not
strong enough for commercial use.
NMFS also explored the use of alu-
minum TED’s but determined that they
would be more costly than those made
from galvanized steel. The aluminum
TED was also too light and was unstable
when towed on the surface, causing the
TED to roll, twisting the codend. In
1983, NMFS also began work on the
collapsible NMFS TED. Both ends of
the deector bars had hinges that al-
lowed this TED to fold for easy space-
saving storage. During shing, the water
tension forced the TED into an open
In 1984, NMFS further modied the
NMFS TED to improve the its handling.
NMFS decided to make the TED even
smaller by reducing the door width from
36 to 30 inches and the frame width from
52 to 42 inches. This reduction would
still allow 95% of turtles to escape. The
remaining 5% represented mostly large
adult loggerheads.
In 1985, NMFS developed a smaller
TED for use in inshore waters. A pro-
totype half-scale TED became easily
fouled and was not large enough to
reduce bycatch. A two-thirds scale TED,
however, reduced bycatch by 50% with-
out any statistically signicant shrimp
loss. This TED became known as the
During the next 2 yr, NMFS con-
ducted eld tests of the NMFS TED
on board cooperative vessels in every
southeast U.S. state with a commercial
eet. These states were North Carolina,
South Carolina, Georgia, Florida, Loui-
siana, Alabama, and Texas. Mississippi
had been the site of previous eld tests,
as it is the home of NMFS laboratory
that developed the NMFS TED. As a
result of the eld tests, NMFS further
modied the NMFS TED, most notably
by removing a shock cord that was used
to hold the accelerator funnel in place.
The shock cord could become lodged
between the front carapace and neck of
sea turtles as they passed through the ac-
celerator funnel, inhibiting their ability
to exit through the TED.
The late 1980’s marked the end of in-
depth research to modify and improve
the NMFS TED. Around 1990 NMFS
focused anew on TED invention, and
these efforts produced the Taylor Soft
TED and the Super Shooter TED, which
will be discussed later. What immedi-
ately followed the NMFS TED era was
a period of increased NMFS cooperation
with the shing industry to test and im-
prove shrimper-invented TED’s. During
this time the protocols for testing TED’s
also evolved.
TED Testing Protocols
Part of the foundation of the effort
to invent a device to reduce sea turtle
bycatch was the development of a pro-
cess by which to test these devices. The
process by which TED’s were evalu-
ated changed signicantly over the rst
15 years of research. Initially, NMFS
evaluated TED’s using a comparative
trawl test design in which one net had
a TED and the other net on the same
vessel did not. NMFS consistently used
this test design through 1985. While this
allowed NMFS to evaluate the shrimp
retention of TED’s under various shing
conditions in numerous states, it was
not well suited to evaluate sea turtle
exclusion. Because researchers did not
know the density of sea turtles in an
area, they could not determine whether a
TED had effectively excluded sea turtles
or whether the trawl did not encounter
any turtles.
In 1986 the UGA MAREX conduct-
ed a demonstration test at Cape Canav-
eral, Fla., that led to the development
of a testing protocol that compared the
number of wild turtles caught in a net
that had a TED with the number of wild
turtles caught in a control net that did
not have a TED. The Cape Canaveral
ship channel was known to have a very
high density of sea turtles, so testing in
this area almost insured that both the
control net and the net with the TED
would encounter sea turtles.
From 1986 to 1989, NMFS used tests
in the Cape Canaveral ship channel to
evaluate industry-developed TED’s
and certify them for commercial use.
For a TED to become certified for
commercial use it must exclude at least
97% of the turtles that enter the trawl
(NOAA, 1990a). This gure is based
on the exclusion rate obtainable with
the NMFS TED. There were several
problems with this protocol including
the unexplained death of a couple of
turtles, the inability to document the
number of turtles entering each net,
and the vague denition of a “captured
turtle.” With the latter problem, it was
often difcult to determine if a turtle
discovered in the net at the end of a test
had entered the net just before the test
ended and would have exited through
the TED if given more time or if that
turtle was truly ensnared in the net.
NMFS abandoned this testing pro-
tocol in 1989, because there was no
longer a high concentration of turtles
in the Cape Canaveral channel. UGA
MAREX continued to survey the turtle
populations in this and other potential
testing sites with dense turtle popula-
tions. By the time the Cape Canav-
eral turtle populations had recovered,
however, NMFS was committed to a
different testing protocol, so testing in
Cape Canaveral has only occurred a
few times since then. In 1988, NMFS
used a new testing protocol to evalu-
ate several TED’s, and this alternative
protocol evolved into the small-turtle
TED testing protocol.
NMFS developed a small-turtle TED
testing protocol for conducting tests
using small sea turtles in the clear waters
off Panama City, Fla., that it has used
32 Marine Fisheries Review
1Mitchell, J. F. 1988. Project report: TED evalu-
ation and video documentation. NMFS, SEFC,
Pascagoula Laboratory, Miss. Available from
consistently since 1990. The protocol
consisted of seven components1:
1) Each day, the researchers random-
ly selected two TED’s and tested
each 10 times. This was repeated
on a second day, so that they tested
each TED a total of 20 times.
2) Turtles were kept in holding pens
until transferred to the test vessel,
where they were held in a ber-
glass tank of seawater.
3) Each turtle was delivered to divers
by placing it in a Herculite bag and
clipping it to a steel messenger
wire that was attached to the trawl.
4) Three divers monitored the test.
Diver number one received the
turtle and released it under and
behind the trawl headrope.
5) Diver number two recorded a)
the time elapsed from the turtle’s
release into the trawl to the turtle’s
encounter with the TED, b) time
elapsed from the turtle’s encounter
with the TED to the turtle’s escape
or removal from the TED, c) turtle
activity code, and d) water clarity
6) Diver number three recorded each
test using an underwater video
7) Once the turtle encountered the
TED, the divers initiated a 2-min
time limit. If after this time the
turtle had not escaped, a diver
removed it. This limit allowed
sufcient time to evaluate TED
performance, limited diver time,
and insured minimal stress to the
Based on an idea originally proposed
by UGA MAREX, the protocol involved
the release of captive-reared juvenile
green turtles into the net and the lming
of their progress through the net. The
turtles had to escape within a certain
time or it was considered captured.
After the rst year of testing, NMFS
increased the testing time limit from 2
to 5 min. If the turtle remained in the
net after the time limit, NMFS declared
it a capture. An even longer time limit
was proposed but blood chemistry tests
revealed that this would increase the
turtle’s stress level.
Over the years, NMFS has improved
the small-turtle testing protocol. To eval-
uate the small-turtle TED testing proto-
col, in 1989 NMFS convened a review
panel that determined the protocol was
limited in that: 1) captive turtles behaved
differently than wild caught turtles, 2)
captive turtles were not as physically t
as wild turtles, and 3) test turtles could
not be introduced to the net in the same
way a wild turtle would be. In response,
NMFS conditioned the turtles in ponds
to make them more physically t.
During the first few years of the
small-turtle testing, many of the turtles
were positively buoyant. NMFS ad-
dressed the buoyancy problem by
improving the turtle’s conditioning,
minimizing their stress, and noting for
consideration during analysis when
turtles displayed buoyancy problems
during the test. Eventually, NMFS
partially addressed the effect of release
position on the test by randomizing the
release location of the turtle into the net.
Although this testing protocol remains
controversial, NMFS believes that the
test is precautionary, because a TED
should exclude a sea turtle no matter
its condition, making any behavioral
abnormalities, such as lack of an escape
response, inconsequential.
After the rst use of the small-turtle
testing protocol, in 1988, NMFS began
to use Kemp’s ridley sea turtles, Lepido-
chelys kempii, because they were easier
to acquire from captive-rearing facilities
and were the species of greatest concern.
When environmental groups protested
the use of highly endangered Kemp’s
ridley sea turtles, in 1994 NMFS began
to use the threatened loggerhead sea
turtle, Caretta caretta.
Even though the small-turtle TED
testing protocol has improved, the
option remained available to certify a
TED using the Cape Canaveral protocol
and was used occasionally for a number
of years. In 1990, NMFS developed the
Modied Cape Canaveral Testing Proto-
col (NOAA, 1990b). Instead of a paired
trawl test design in which one trawl had
an experimental TED and the other did
not have a TED, under the modied
protocol both nets had an experimen-
tal TED. Each of the trawls were also
mounted with an underwater camera that
allowed NMFS technicians to monitor
the wild turtles that entered the net.
With the modied protocol, the turtle is
given 10 minutes to escape. If the turtle
does not escape within 10 minutes, the
turtle is considered captured, the trawl
is retrieved, and the turtle is released. It
is important to note that only one type
of test protocol could be given to a TED,
so failure of either test meant failure of
the TED. No further testing was allowed
unless the TED was modied.
To pass the certication test with any
of the protocols, the candidate TED had
to exclude 97% of turtles with a 90%
condence interval, according to the
standard set by the control TED during
that round of testing. Initially, NMFS
used the NMFS TED as a control,
because it was the most extensively
tested TED and was 97% effective in
excluding turtles. Using the NMFS
TED as a control addressed the varia-
tions between the Cape Canaveral and
small-turtle testing protocols, because
the NMFS TED had a known exclusion
rate. Any variation in this rate could be
viewed as an artifact of the small-turtle
testing protocol and was adjusted for in
the statistical analysis.
In 1996, NMFS began using the Super
Shooter TED as the control TED. NMFS
calculated the probability of Type I and
Type II errors in order to insure that
the sample size of the test was large
enough that a statistical analysis would
be powerful enough to correctly reject or
accept a TED. Based on this calculation,
NMFS eventually increased the number
of turtles released into the candidate
TED from 20 to 25.
NMFS invited TED inventors and
manufacturers to participate in the
testing. NMFS allowed the inventor to
install the TED, view preliminary video
of the TED’s underwater performance,
and make adjustments if necessary. If the
TED was failing or had failed the test,
NMFS or the inventors could modify
74(2) 33
the TED and retest during the same test
session if time allowed.
NMFS gave copies of the testing
videos to the TED inventors and manu-
facturers and invited them to attend
the TED Testing Review Committee
meeting. This committee was comprised
of Sea Grant agents, shrimp fishing
industry representatives, shing gear
specialists, and sea turtle experts. The
committee reviewed the video of each
test and could score the test as a capture
or escape or they could choose to dis-
card the test. In 1995, however, NMFS
abandoned use of the review panel and
the process of scoring the tests, because
the criteria for making classications
were too vague.
Testing of Industry-developed
While NMFS was developing the
NMFS TED, members of the shrimp
shing industry had begun to develop
different types of TED’s, and several
of these inventors worked closely with
Sea Grant to evaluate the devices. Fol-
lowing the successful demonstration in
Cape Canaveral in 1986, in 1987 NMFS
joined this effort and began eld tests
of some of these devices. That year
marked a turning point in the NMFS
TED program, as most of the effort in
the following years focused on evaluat-
ing, testing, and modifying TED’s that
members of the shrimp shing industry
designed. Three designs in particular
made substantial early advances in TED
design. These were the Georgia Jumper,
invented by Sinkey Boone of Darien,
Ga.; the Morrison Soft TED, invented
by Sonny Morrison of McClellanville,
S.C.; and the Anthony Weedless TED,
invented by Ernest Anthony of La-
combe, La.
The Georgia Jumper was the first
frameless TED; the oval shaped metal
frame was sewn directly into the net at
a 45° angle (Fig. 7). Beginning in 1987,
NMFS frequently evaluated modica-
tions of the Georgia Jumper. Much of
this work focused on how the device
was congured in the net; the grid itself
has remained largely unchanged. NMFS
certied the Georgia Jumper for com-
mercial use in 1987.
Figure 7.—Georgia Jumper TED (Source: S. Boone. Patent application. [Available
from Jenkins.]).
The Morrison Soft TED was the rst
TED to use exible mesh webbing (as
opposed to a rigid grid) as the separa-
tor panel in the TED (Fig. 8). Unlike a
grid that is placed in the throat of the
trawl net, the soft TED panel begins in
the mouth of the trawl and tapers back,
forming a mesh ramp to the escape open-
ing. NMFS evaluations and modica-
tions of this TED centered on rening
it so that it would perform consistently
across styles of nets and shing environ-
ments. NMFS certied it for commercial
use in 1987. The Parker Soft TED,
which is a variation of the Morrison Soft
TED, is currently the only soft TED that
remains certied (Fig. 9).
The Anthony Weedless TED was the
rst TED design to solve the problem
of TED’s becoming clogged with veg-
etation and similar debris (Fig. 10). It
consisted of a frameless grid, the bars of
which did not attach to the bottom of the
grid, allowing debris to enter the codend
rather than clog the TED. In comparison
to other TED’s, NMFS certied this
TED by proxy to its similarity to the
Georgia Jumper with limited evalu-
ations, focusing on shrimp retention.
Subsequent to its certication, NMFS
analyzed the impact of an improperly
installed Anthony Weedless TED on sea
turtle escapement.
In addition to the innovative Georgia
Jumper, Morrison Soft, and Anthony
Weedless TED’s, NMFS evaluated,
tested, or modied over 30 different
shing industry-invented TED designs.
This number does not include the many
modications and version of each design
nor the over 15 designs that were pro-
posed but never tested.
The shing industry and other stake-
holders attacked the sea turtle bycatch
problem from all angles. Most of the
ideas were variations on barrier devices,
hard TED’s, and soft TED’s. Others
were more novel, such as the Sonic Ex-
cluder. This device, invented by Daniel
Leveque of Lake Charles, La., Michael
Tritico of Longville, La., and Martin
Lenhardt of the Virginia Institute of
Marine Science, used sound waves to
ward turtles away from an approaching
trawl. Another novel device, the Turtle
Detection Device, invented by Ricky
Bourg of Dulac, La., consisted of a
mechanical trigger located at the codend
attachment point that released a tethered
oat from the trawl when a sea turtle or
large object was encountered (Fig. 11).
The shrimp fishing industry also
proposed a number of TED accesso-
ries. One such device was the Pierce
Shrimp Broom invented by Webster
Pierce and Mitch Serigne of Louisiana
(Fig. 12). This broom of plastic bers
was attached to a TED frame so as to
prevent shrimp from exiting through the
escape opening. During testing in 1995,
34 Marine Fisheries Review
Figure 8.—Morrison Soft TED (Source: J. F. Mitchell. 1989. Project report: soft TED
evaluations, video documentation and small turtle tests. NMFS, SEFC, Pascagoula
Laboratory, Miss. [Available from Jenkins.]).
this device excluded all turtles. Other
notable accessories were the Darien
Roller and Georgetown Roller (Fig.
13). These similar devices consisted of
a PVC pipe attached to the bottom of
the TED frame. NMFS certied these
devices for use to prevent chafng and
tearing of the net.
The years of cooperation between
NMFS and the shing industry resulted
in TED’s that were increasingly efcient
in releasing turtles and more effective in
retaining shrimp. The designs reected
the collective scientic, engineering,
and shing knowledge of NMFS per-
sonnel, Sea grant agents, and industry
collaborators. However, there are two
major points of difference between
NMFS and industry in the approach
to TED design: whether turtles were
released more effectively from top or
bottom-opening TED’s and whether soft
Figure 9.—Parker Soft TED (Source:
Mitchell, J. F. and W. Taylor. 1997.
Report on small turtle TED test:
phase 2 soft TED testing. NMFS,
SEFC, Pascagoula Laboratory, Miss.
[Available from Jenkins.]).
Figure 10.—Anthony Weedless TED
(Source: NMFS, SEFC, Pascagoula
Laboratory, Miss. [Available from
TED’s could effectively and consistently
exclude turtles.
Bottom-opening vs.
Top-opening TED’s
To determine if TED’s performed
better as top opening or bottom opening,
NMFS evaluated four different TED
designs (the NMFS TED, the Georgia
Jumper, the Anthony Weedless TED,
and the Super Shooter TED) in 1995
and 1996 in a total of 14 different shing
congurations using captive-reared sea
turtles. All the top-opening TED designs
had equal or better turtle exclusion rates
than their bottom opening counterpart.
With the exception of one conguration
of bottom-opening Super Shooter TED,
all the top-opening TED’s had shorter
escape times than their bottom opening
counterparts. In fact, the escape times
of top-opening TED’s (55–85 sec) were
74(2) 35
Figure 11.—Turtle Detection Device (Source: NMFS, SEFC, Pascagoula Laboratory, Miss. [Available from Jenkins.]).
often about half that of bottom-opening
TED’s (64–177 sec).2
Soft TED Testing
In response to growing concerns that
soft TED’s were catching high numbers
of sea turtles, NMFS evaluated soft
TED’s almost exclusively from 1996
through 1998. In 1996, NMFS obtained
ve Andrews Soft TED’s from three
different net shops to evaluate the con-
sistency of installation and turtle exclu-
sion. Of the ve TED’s, four apparently
had installation problems that resulted
in areas of slack webbing in the TED
(Fig. 14). Small turtles released near
the wings of the TED had signicantly
higher relative capture rates (70%) than
those released in the center position
NMFS then convened a soft TED
advisory panel in March 1997 to develop
4Mitchell, J. F., and W. Taylor. 1997. Report of
small turtle TED test: phase 1 soft TED testing.
NMFS, SEFC, Pascagoula Laboratory, Miss.
Available from Jenkins.
2Mitchell, J. F., D. Foster, and J. Watson. 1996.
1996 TED testing: summary of evaluations and
results. NMFS, SEFC, Pascagoula Laboratory,
Miss. Available from the author of this paper.
NMFS. 1995. 1995 TED certication test.
NMFS, SEFC, Pascagoula Laboratory, Miss.
Available from Jenkins.
3Mitchell, J. F., D. Foster, and J. Watson. 1996.
1996 TED testing: summary of evaluations and
results. NMFS, SEFC, Pascagoula Laboratory,
Miss. Available from Jenkins.
technical solutions to the operational
problems with soft TED’s. Panel mem-
bers included soft TED designers and
shrimp industry representatives. The
industry panel developed ideas for soft
TED modications and submitted them
to NMFS for testing and diver evaluation.
Of 18 soft TED designs evaluated during
the project, seven were variations of the
Andrews Soft TED and eleven were
variations of the Morrison Soft TED.
NMFS identified design problems
that prevented the escape of juvenile
turtles in 15 of the 18 soft TED’s. Of
the 18 designs, one successfully passed
the test protocol by excluding 22 of 25
turtles. The successful design was the
Morrison 4 × 8 inch Soft TED (later
known as the Parker Soft TED), con-
structed with 8 inch webbing in the main
panel and 4 inch webbing in the wings
and at the exit hole apex. In addition, the
researchers developed and conducted
preliminary tests of an Andrews Soft
TED with a combination of 6, 3 and 5
inch webbing panel.4
Later that year, NMFS continued
its evaluation of soft TED’s, focusing
on further evaluations of the Morrison
4×8 inch Soft TED installation in vari-
ous trawl types and sizes and continued
testing of Andrews TED designs. The
Morrison 4×8 inch Soft TED was in-
stalled in the following trawl types: 1)
2-seam balloon with and without a bib
(i.e., a section of webbing extending
forward from the net’s top panel and
connecting to a third central bridle); 2)
4-seam balloon with and without a bib;
3) mongoose; and 4) straight wing at.
On the trawl designs with bibs (which
helps to maintain optimal spread of the
mouth of the trawl), NMFS evaluated
TED panel conguration at different
center wire adjustments. The Andrews
Soft TED evaluation and testing resulted
in the development of three designs
which successfully passed the test pro-
tocol. These designs were the Andrews
4 × 8 inch Soft TED , Andrews 6 × 3 × 5
inch Soft TED, and Andrews 5 inch
Soft TED.5
Following the 1997 tests, members of
the Soft TED Advisory Panel evaluated
shrimp retention of the Andrews 4×8
inch Soft TED aboard a commercial
5Mitchell, J. F., and W. Taylor. 1997. Report on
small turtle TED test: phase 2 soft TED testing.
NMFS, SEFC, Pascagoula Laboratory, Miss.
Available from Jenkins.
36 Marine Fisheries Review
shrimp trawler and estimated a 20%
loss of shrimp in comparison to a hard
TED. Based on these ndings, a subse-
quent meeting of the Soft TED Advisory
Panel recommended that NMFS take no
further action to certify any of the An-
drews Soft TED designs which passed
the eld tests in 1997. The panel did,
however, recommend that NMFS focus
the 1998 TED testing on modications
to improve the shrimp retention of the
Andrews Soft TED. In 1998, NMFS
certied the Parker Soft TED; this was
the only certication awarded of all the
soft TED designs explored during these
3 yr of intensive research.6
Taylor Soft TED
In addition to the NMFS TED,
NMFS scientists and gear specialists
developed other distinct TED designs.
One of these was the Taylor Soft TED.
Charles “Wendy” Taylor, an NMFS
gear specialist and former commercial
6Mitchell, J. F., and W. Taylor. 1998. Report on
small turtle TED test: modied Andrews TED
testing. NMFS, SEFC, Pascagoula Laboratory,
Miss. Available from Jenkins.
Figure 12.—Pierce Shrimp Broom (Source: NMFS. 1995.
1995 TED certication test. NMFS, SEFC, Pascagoula Lab-
oratory, Miss. [Available from Jenkins.]).
Figure 13.—Darien Roller (Source: J. F. Mitchell. 1994.
1994 TED certication test. NMFS, SEFC, Pascagoula Lab-
oratory, Miss. [Available from Jenkins.]).
Figure 14.—Andrews Soft TED indicating observed areas of slack webbing and
pocketing. (Source: Mitchell, J. F., D. Foster, and J. Watson. 1996. 1996 TED test-
ing: summary of evaluations and results. NMFS, SEFC, Pascagoula Laboratory,
Miss. [Available from Jenkins.]).
net builder invented the Taylor Soft
TED (Fig. 15). The need for this device
evolved from industry’s desire for a
smaller mesh size soft TED with a ap
and the need for a soft TED suitable for
small trawls. The TED was a modica-
tion of the Morrison Soft TED. It was a
top-opening TED made from a triangu-
lar piece of 6 inch mesh polyethylene
webbing that formed a shortened panel
and had a ap weighted with a chain
over the exit hole. There were two
designs of the Taylor Soft TED: in one
design the panel ends in a single mesh
74(2) 37
(an apex) and in the other design the
panel is squared-off.
During testing in 1991, diver ob-
servation revealed that the panel of
the Taylor Soft TED was too far aft,
preventing lateral expansion so the
meshes were partially closed. This
resulted in the blockage of the codend
entrance and the misdirection of water
ow. Taylor corrected the problem by
moving the TED forward 5 ft and in-
creasing the hanging ratio of the mesh.
Following this adjustment, the TED
successfully excluded 100% of turtles
placed in the net with no statistically
signicant loss of shrimp.
Super Shooter TED
Another TED that NMFS had a sig-
nicant role in inventing was the Super
Shooter TED. Noah Saunders of TED,
Inc., in Biloxi, Miss., began developing
the Super Shooter TED around 1989
in cooperation with NMFS personnel,
particularly Dale Stevens and John
Watson. A modication of the Georgia
Jumper, the aluminum rod bars of this
TED were bent at a 45º angle just above
the bottom of the frame to prevent clog-
ging by debris. This design differs from
the Georgia Jumper in that it does not
have a crossbrace because its greater
width and larger diameter material adds
This TED was manufactured in three
sizes. The large size Super Shooter TED
consists of a 42×51 inch frame spaced
4 inch apart. The Mini Super Shooter
(also known as the small size or mid
size Super Shooter TED) (Fig. 16) had
a 33×41 inch frame with bars spaced 3.5
inch apart. The Inshore Super Shooter
TED had a 32×35 inch frame with bars
spaced 3.75 inch apart. During eld
tests the Super Shooter TED had no
statistically signicant loss of shrimp
and excluded 100% of turtles placed
in the net.
Cooperative Work with Mexico
In addition to inventing the NMFS
TED and working with industry to
test and modify shrimper-invented
TED’s, NMFS also cooperated with
the governments of several foreign
nations in developing new TED
designs. One of the first such rela-
tionships was with Mexico. In 1992,
NMFS and the Instituto Nacional de
La Pesca (INP), the primary agency
for scientific and technological
advice on fisheries development and
assessment in Mexico, conducted
comparative trawl tests of the Super
Shooter and Anthony Weedless TED’s
in Mexico’s Gulf waters.
In 1994, NMFS observed and sug-
gested modifications to two TED’s
designed by the INP. The most unique
of the two designs was the INP 3-bag
TED (Fig. 17), which had an oval grid
and three codends. Two bafes, one in
each wing, led to two outer codends.
Behind the bafes was the TED leading
to the center codend. The Mexican gear
specialists explained that shrimp travel
along the trawl wings and so will enter
the bafes before reaching the TED,
thus reducing loss of shrimp.
Based on initial observations, the
bafes were modied by lacing nylon
line along the perimeter to keep them
open. During subsequent tests, the TED
caught 3 of 5 turtles; the captured year-
ling turtles became entangled in one of
the bafes. NMFS suggested the TED
be modied by placing a barrier over
the bafes and adding side hoops to
the TED frame to assure that the outer
codends remain open.
The second design, the FEDINP
TED was more traditional in appear-
ance. This was a top-opening TED
with a 31.5 × 50.5 inch rectangular grid
made of 1.5 inch aluminum tubing.
The exit hole had nylon rope laced to
the perimeter and was covered by a 1
inch stretched mesh ap that extended
23.5 inch beyond the frame. During
testing, this TED successfully excluded
all turtles.
Leatherback TED’s
The early 2000’s brought sweeping
changes to TED regulations; this result-
ed in a new focus for the TED research
program. The regulatory changes were
prompted in part by a study published
Figure 15.—Taylor Soft TED (Source: NMFS, SEFC, Pascagoula Laboratory, Miss.
[Available from Jenkins.]).
38 Marine Fisheries Review
in 2002 that showed that as many as
47% of stranded (i.e., recovered car-
casses) loggerhead turtles and 7% of
stranded green turtles had body depths
that exceeded the minimum legal TED
opening height (Epperly and Teas,
2002). The study indicated that these
large sea turtles might be drowning in
trawl nets.
On 21 Feb. 2003, in response to
the mounting scientic evidence that
sea turtle conservation measures were
inadequate for protecting large turtles,
NMFS enacted several changes to the
TED regulations (NOAA, 2003). Nota-
bly, these new regulations required all
offshore single-grid hard TED’s to have
a grid with a minimum measurement of
32 × 32 inch. They also required that all
offshore TED’s be equipped with either
a 6 inch overhang double-cover ap
(Fig. 18), which has an escape open-
ing of at least 56 × 20 inch, or the 71
inch standard leatherback modication
(Fig. 19), which has an escape opening
with a minimum of 71 inch straight-
line stretched mesh. These regulatory
changes effectively decertied many
of the previously certied TED’s. This
caused NMFS’ TED research to shift
focus into modication of previously
certied TED’s, such as the Georgia
Jumper, whose opening required modi-
cation to meet the larger escape opening
Flat Bar TED
To handle the rigors of deepwater
shing, offshore shrimpers began using
larger TED’s made of sturdy aluminum
or steel pipe to prevent bending of the
frame. But some shrimpers noted that
there was an increased loss of shrimp
in these TED’s in comparison to TED’s
made from thinner materials. In 2005,
using a ume tank facility, NMFS gear
specialists determined that the minimal
grid surface area of a TED made from
aluminum flat bar led to almost no
water ow diversion when compared
to an aluminum pipe TED. Less water
ow diversion leads to more shrimp
remaining in the net rather than owing
out the TED escape opening.
The Flat Bar TED (Fig. 20) was also
equal to a pipe TED in frame strength.
The Gulf and South Atlantic Fisheries
Foundation, Inc., completed a study in
2007 and found that the aluminum Flat
Bar TED had statistically signicant
increases in shrimp catch rates when
compared to an aluminum pipe TED.7
In 2006, a Flat Bar TED with deec-
tor bars constructed from aluminum
at bar stock, 1/4 inch in thickness
and 1 1/2 inch in depth, successfully
passed the small turtle test protocol
by excluding 24 of 25 turtles (NOAA,
Figure 16.—Mid-size Super Shooter TED (Source: NMFS.
1995. 1995 TED certication test. NMFS, SEFC, Pasca-
goula Laboratory, Miss. [Available from Jenkins.]).
Figure 17.—INP 3-bag TED (Source: J. F. Mitchell. 1994.
1994 TED certication test. NMFS, SEFC, Pascagoula Labo-
ratory, Miss. [Available from Jenkins.]).
7Gulf and South Atlantic Fisheries Foundation,
Incorporated. 2008. An assessment of turtle ex-
cluder devices within the Southeastern shrimp
sheries of the United States. NOAA/NMFS
Cooperative Agreement No. NA04NMF4540112;
74(2) 39
Double Shoot TED
Debris clogging TED’s is a chief
concern for shrimpers, especially after
hurricanes. NMFS gear specialists
tackled this concern by creating the
Double Shoot TED (Fig. 21). This
TED has two openings. One opening
on the bottom discharges heavy debris
and another opening on the top allows
escape of turtles. The TED also has a
xed shing angle of the TED deector
bars through a dual-angle design that
resembles a less than symbol (<). In
2010, this Double Shoot TED passed
the small-turtle TED testing protocol
by excluding all 25 turtles. A paired-
trawl test with a standard top-opening
grid TED showed that the Double Shoot
TED reduced nsh bycatch by 11.6%
with a 5.5% reduction in shrimp catch
(USDOC, 2011).
TED’s in Other Trawl Fisheries
In 2007 NMFS published an Ad-
vance Notice of Proposed Rulemak-
ing to require TED’s in other sheries
(NOAA, 2007). Then, in 2009, NMFS
published a notice of intent to prepare
an environmental impact statement
in preparation for possible regulatory
changes that would require the use of
TED’s in trawl sheries with docu-
mented sea turtle interaction, such as
those for knobbed whelk, Busycon
carica, and Atlantic sea scallops,
Placopecten magellanicus (NOAA,
2009). In anticipation of this potential
regulatory change, NMFS began test-
ing TED’s for these sheries. Much of
the initial work was based on a device
Figure 18.—Double Cover Flap (Source: NOAA, 2001a).
40 Marine Fisheries Review
Figure 19.—Leatherback Modication (Source: NOAA, 2001b).
Figure 20.—Flat Bar TED lean-
ing against a mooring. (Source: J.
Watson. 2005. Sea Turtle Bycatch
Reduction Research in the U.S. 1st
Annual Meeting of the Bycatch
Reduction Consortium, 1–2 June
2005, Boston, Ma. http://www.neaq.
Figure 21.—The Double Shot
TED frame prior to installation in
webbing extension tube (Source:
USDOC, 2011).
Figure 22.—Flounder TED (Source:
Belcher, C., R. Vendetti, G. Gaddis,
and L. Parker. 2001. Results of gear
testing to reduce turtle capture in
the whelk trawl shery. Georgia Sea
Grant College Program. [Available
from Jenkins, and online at georgia-
called the ounder TED (Fig. 22). This
TED features large holes at the bottom
of the TED that will allow the passage
of ounder into the codend but will still
block the passage of sea turtles. Since
1992, all boats using bottom trawls to
catch summer ounder, Paralichthys
dentatus, at certain times and areas
off Virginia and North Carolina have
been required to use TED’s in their nets
(NOAA, 1992). In 2010, NMFS ap-
proved the use of a Modied Flounder
TED (Fig. 23), which consisted of two
grid frames that allowed the TED to be
rolled onto a net reel. The Northeast
Fisheries Science Center and indus-
try developed this TED to improve
catch retention by reducing clogging
(NOAA, 2010).
Because whelk and flounder are
both larger bottom dwelling organisms,
modifying the flounder TED was a
74(2) 41
starting point for developing a TED ap-
propriate for whelk. The whelk shery
occurs primarily in Georgia and South
Carolina and arose as an alternative
shery during times when the shrimp
shery was closed. The whelk TED
was developed in cooperation with
the Georgia Department of Natural
Resources (GADNR) and the UGA
NMFS evaluated these potential
TED designs in 2000–01. During the
2000 TED testing, the whelk TED
excluded all 25 turtles placed in the
TED, but shermen thought that the
frame was too large for their trawls. In
2001, NMFS tested the Whelk TED II
(Fig. 24). The height of this TED had
been reduced from 52 to 36 inch and
the outer frame was constructed from 2
inch at bar. The at bar allowed whelk
to roll through the bottom openings of
the TED more efciently than a pipe
The at bar, however, caused small
turtles to be trapped on the lip of
the bar, over which they could not
maneuver. NMFS gear specialists rec-
ommended that the top section of the
outer frame near the escape opening
should be replaced with pipe rather
than at bar. Following this modi-
cation, the whelk TED II passed the
NMFS small-turtle testing protocol,
capturing only 1 of 24 turtles. Cur-
rently, GADNR requires the use of
Figure 23.—Modied Flounder TED (Source: NOAA, 2010).
42 Marine Fisheries Review
this TED in the whelk trawl shery in
Georgia waters.
Sea turtle bycatch has also been
documented in the Atlantic sea scallop
trawl sheries. In 2005 and 2006, NMFS
tested the feasibility of using a whelk
TED modified with chaffing gear in
the sea scallop trawl shery. This TED
design passed the NMFS testing criteria,
and NMFS is now considering requiring
the use of TED’s in the Mid-Atlantic sea
scallop trawl shery. Also, the Atlantic
sea scallop dredge shery has worked
with NMFS to develop a turtle exclud-
ing dredge.
The ynet shery is another trawl
fishery with documented sea turtle
bycatch. Flynets are high-prole trawls
of 80–120 ft width and are shed just
above the seaoor. The ynet shery
is a multispecies shery that operates
along the east coast from New York to
North Carolina. Depending on shing
location and depth, target species in-
clude Atlantic croaker, Micropogonias
undulatus; weaksh, Cynoscion regalis;
Figure 24.—Whelk TED II (Source: NMFS. 2001. Report on FY 2001 Small Turtle
TED Test. NMFS, SEFC, Pascagoula Laboratory, Miss. [Available from Jenkins.]).
Atlantic mackerel, Scomber scombrus;
bluesh, Pomatomus saltatrix; squid,
Teuthida; black sea bass, Centropristis
striata; scup, Stenotomus chrysops; and
other nshes.
NMFS began developing a TED for
this shery in 1999. Initially, two of
these TED’s passed the NMFS small-
turtle TED testing protocol. Both TED’s
had folding, hinged frames to facilitate
winding around the vessel net reel, but
the industry was concerned that this
design could cause excessive loss of
In response to this concern, NMFS
developed a bifolding TED called the
Staggered Bar Flynet TED (Fig. 25).
The staggered bar conguration was
designed to let more sh into the net
bag by reducing the number of sh that
are deected through the exit hole of the
TED. After correcting the installation
position of the TED so that the offset
bars faced into the water ow, this TED
excluded all 25 turtles that were placed
in the net.
Since about 2009, NMFS returned
to exploring a flexible grid design
for the ynet shery. They have had
considerable success with a TED
constructed of aluminum at bar with
a center section made of stainless
steel cable, which allows it to ex
for storage around the net reel. Ver-
sions of this device have successfully
passed the turtle test protocol and
have reduced bycatch of spiny dog-
sh, Squalus acanthias, by 40% and
clearnose skates, Raja eglanteria, by
63% without signicant loss of target
catch (USDOC, 2010, 2011). If NMFS
decides to require the use of a TED in
the ynet shery, it might initially only
require TED’s for vessels targeting
weaksh and croaker.
In this article I have chronicled the
contributions of NMFS to the inven-
tion and development of TED’s. I
summarized the impetus for and results
of major events, including the initial
74(2) 43
Figure 25.—Staggered Bar Flynet TED (Source: NMFS. 2000. Report on FY 2000 Small Turtle TED Test.
NMFS, SEFC, Pascagoula Laboratory, Miss. [Available from Jenkins.]).
44 Marine Fisheries Review
attempts to develop a barrier device;
development of the NMFS invented
and the NMFS modied TED’s, such
as the NMFS TED, Taylor Soft TED,
and Super Shooter TED; and testing
and development of industry-invented
TED’s, such as the Georgia Jumper,
Morrison Soft TED, and Anthony
Weedless TED. I have also recorded
details of little known events in the
TED research, such as the testing of
novel TED designs invented by gear
specialists from the Mexican govern-
ment and alerting devices, such as
the Sonic TED and Turtle Detection
This summary of 36 years of his-
tory, shows how the NMFS program to
reduce mortality of sea turtles in trawls
has grown. The program has progressed
from reactive research in response to
the regulatory change of the listing
of sea turtles under the Endangered
Species Act to anticipatory research in
preparation for potential TED require-
ments in additional trawl sheries. As
a result of efforts of NMFS and numer-
ous stakeholders, many trawl sheries
around the world now use a version
of the turtle excluder device (TED). I
hope that this record of TED research
will further aid the development of
TED’s for appropriate trawl sheries
I would like to acknowledge my
Ph.D. advisors Larry Crowder and
Michael Orbach for their advice and
support over the course of my disserta-
tion research at Duke University. I ap-
preciate the assistance of Lee Benaka,
John Mitchell, and the many key
informants who provided information
for this research. I am grateful to the
two anonymous reviewers for their
editorial suggestions and to TWIG for
their encouragement. I would also like
to thank the National Science Founda-
tion and the Oak Foundation for funding
this research.
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... There have been some remarkable successes in the use of bycatch reduction technologies. For instance, the introduction of turtle excluder devices (TEDs) in shrimp trawls in the Gulf of Mexico has dramatically reduced the bycatch mortality of endangered sea turtles (reviewed by Jenkins, 2012). The declines of finfish bycatches in many shrimp trawl fisheries have largely been the result of the sorting grids and selection panels introduced in these fisheries (Isaksen et al., 1992;Broadhurst, 2000). ...
... My work has focused on the reduction of bycatch mortality in trawl fisheries (e.g. Suuronen and Millar, 1992;Suuronen, 1995;2005), but I have worked also with gillnet, long-line, and trap-net fisheries (Tschernij et al., 1993;Suuronen et al., 2006;2012;Gilman et al., 2016). In 2009-2017, when I worked at the Fisheries and Aquaculture Department of the Food and Agriculture Organization of the United Nations (FAO), my first task was to draft the International Guidelines on Bycatch Management and Reduction of Discards (FAO, 2011). ...
Full-text available
Reducing the capture of non-target species and juvenile fishes through a variety of gear modifications and bycatch reduction devices are presumed to provide long-term biological and socioeconomic benefits and improve the reputation of fisheries. The adoption of these technologies by fisheries, however, has been low compared to research and development efforts. Research has focused on technical design and catch rate responses to these technological interventions with a limited focus on assessing fishers’ attitudes towards these technologies. This essay gives a personal reflection, based on an extensive collaboration with fishers, of the perspectives and barriers that may affect their responses. I also provide suggestions on how to genuinely engage fishers in the process that could lead to agreeable solutions. Above all, change should be approached from the perspective of those whose behavior one is seeking to influence, acknowledging the heterogeneity among fisheries and fishers. The essential element for the success is fishers’ motivation and readiness to the change. Fishers need a clear vision of what the changes mean for their livelihood and evidence that the technology to minimize bycatch performs sufficiently well in various conditions.
... Turtle bycatch has been a Federal regulation issue since the 1970s, when the species was first regulated under the Endangered Species Act (ESA) of 1973 (Jenkins, 2012). The ESA forbids the "taking" (or killing) of any species that is "listed" as an endangered species and requires regulation to minimize the taking of endangered species (EPA, 2022). ...
... Each outrigger drags one or two nets equipped with two wooden doors, ∼3-10 feet long (Figure 1). These doors slide on their edges along the seabed, where water pressure and a connecting chain keep them apart with the net between (Jenkins, 2012). After dragging for a period of time (2-3 h), the nets are winched onboard, and emptied on the deck. ...
The “Georgia Jumper” turtle excluder device (TED) is a rare example of a well-accepted conservation tool required by regulation. Mediated by the UGA Marine Extension and Georgia Sea Grant, Georgia's shrimping industry was integral to the design, revision, and implementation of excluder devices, since the earliest “jellyball shooter” proposed to NMFS in 1980. This paper highlights fisher involvement in the creation of the popular “Georgia Jumper” TED. Both the Diffusion of Innovation and the Traditional Ecological Knowledge literatures stress the importance of meaningful engagement of user communities in the development of new management approaches, and make specific recommendations for improving uptake of new methods. Consistent with literature expectations, fisher and industry participation in the development, testing, and implementation of TEDs has been key to the general acceptance of TEDs in Georgia. This paper illustrates the importance of fisher participation in conservation efforts such as these.
... Tropical shrimp trawls in the Gulf of Mexico faced bycatch of sea turtles and juveniles of important commercial fish species such as Red Snapper (Lutjanus campechamus). While sea turtle bycatch was significantly reduced through the testing and introduction of various turtle excluder devices (TEDs, also called trawl efficiency devices) in the 1980s and 90s (Jenkins, 2012;Watson et al., 1999), fish bycatch persisted. Researchers in the Gulf of Mexico have conducted a series of studies on topics ranging from behavior of relevant species to gear designs to reduce fish bycatch in shrimp trawls in the last 30 years. ...
... However, the same measures may be easier to promote and be accepted if limited in space (high bycatch areas), time (certain months), or both. TEDs were originally designed for shrimp fisheries with a rigid grid (Jenkins, 2012) that was ineffective in the Adriatic (Sala, Lucchetti & Affronte, 2011). In general, ...
Full-text available
Studying the impact of bycatch on marine megafauna, including sea turtles, is challenging for a variety of technical and biological reasons. The Mediterranean Sea has among the highest levels of turtle bycatch globally, notably of the loggerhead sea turtle (Caretta caretta), and bottom trawling represents a particularly relevant threat. Bottom trawlers from a recently discovered neritic foraging area, the Gulf of Manfredonia, reported 1,152 loggerhead turtles incidentally caught in the period 2015–2020. Capture locations were available for 497 turtles. These data were complemented by the distribution of fishing effort obtained by the vessel monitoring system. High bycatch rates were observed, leading to more than an estimated 5,600 annual captures and to the death of a minimum of 560 large individuals with high reproductive value. These findings are extremely concerning for the affected population and require immediate action. A strong seasonality of turtle bycatch was observed, with most captures occurring in November–March when fishing effort occurs in shallow waters where turtles concentrate all year round. Therefore, a seasonal approach (e.g. adopting measures only in the high‐turtle bycatch season) can be pursued as long as the spatial distribution of fishing effort varies among seasons. However, such a spatio‐temporal pattern should be monitored; then, in the case of change, although more difficult to implement, an area‐based conservation approach should be pursued. Several recommendations are provided, including the urgent implementation of turtle excluder devices, at least on a seasonal basis. This case shows that identifying the best conservation approaches requires information on the actual spatio‐temporal pattern of turtle occurrence and bycatch. Such information can only be derived from spatial distribution of bycatch and fishing effort obtained through a voluntary collaboration of fishers.
... In Mediterranean gillnet fisheries, marine megafauna bycatch interactions have resulted in considerable costs and downtime to fishers who need to repair nets. 51 Adoption potential, study limitations, and future directions Although most BRTs have historically been developed for specific bycatch taxa, 24,25,52,53 solutions that reduce total bycatch discards could mitigate implementation costs and ease broader adoption in fisheries that interact with multiple bycatch species. 32,34 The significant reduction in total bycatch is important when considering the likelihood of fisher adoption, as bycatch events of protected species tend to be rare, which can make the impetus for uptake of new technologies or compliance with regulations more abstract to fishers. ...
Small-scale fisheries are vital for food security, nutrition, and livelihoods in coastal areas throughout the world’s oceans.1, 2, 3, 4, 5, 6, 7, 8, 9 As intricately linked social-ecological systems, small-scale fisheries require management approaches that help ensure both ecological and socioeconomic sustainability.⁷,10, 11, 12, 13, 14 Given their ease of use and lucrative nature, coastal gillnet fisheries are globally ubiquitous.¹⁰,¹⁵ However, these fisheries often result in high discarded capture of non-target organisms (bycatch) that can lead to significant cascading effects throughout trophic chains16, 17, 18 and costly fisheries restrictions that result in important revenue losses in coastal communities with scarce economic alternatives.¹⁹,²⁰ Despite these challenges, few solutions have been developed and broadly adopted to decrease bycatch in coastal gillnet fisheries, particularly in developing nations.⁵,²¹ Here we used controlled experiments along Mexico’s Baja California peninsula to show that illuminating gillnets with green LED lights—an emerging technology originally developed to mitigate sea turtle bycatch—significantly reduced mean rates of total discarded bycatch biomass by 63%, which included significant decreases in elasmobranch (95%), Humboldt squid (81%), and unwanted finfish (48%). Moreover, illuminated nets significantly reduced the mean time required to retrieve and disentangle nets by 57%. In contrast, there were no significant differences in target fish catch or value. These findings advance our understanding of how artificial illumination affects operational efficiency and changes in catch rates in coastal gillnet fisheries, while illustrating the value of assessing broad-scale ecological and socioeconomic effects of species-specific conservation strategies.
... This concern was a value (i.e., part of culture) and specific to only a portion of the shrimp fishery. To address this value, federal government scientists and Sea Grant extension agents created TEDs that also reduced finfish bycatch (Jenkins, 2012). However, in some shrimp fisheries, especially in developing countries, the crew is paid in part or in whole with the bycatch of finfish, so a TED that also excludes finfish would not be embraced in these locations. ...
Full-text available
The term conservation technology is applied widely and loosely to any technology connected to conservation. This overly broad understanding can lead to confusion around the actual mechanisms of conservation within a technological system, which can result in neglect and underdevelopment of the human dimensions of conservation technology, impacting its effectiveness. This paper offers precise definitions of marine conservation technology and a technological marine conservation system. It summarizes some of the concerns about the use of marine conservation technologies. It discusses in depth how technology and technological systems can have power, politics, and culture. It proposes the social‐ecological‐technological systems framework to incorporate this broader understanding, so that the values and concerns of people, groups, and society are more effectively addressed in the creation and implementation of marine conservation technologies and technological marine conservation systems. This article is protected by copyright. All rights reserved
... For example, 'excluders' built into fishing nets have been shown to reduce bycatch markedly (e.g. sea turtles [27]), with potential to reduce unwanted capture of large ray species [28]. The SWG recommended research into such technical innovations which may reduce skate bycatch [14] including the removal of "tickler" chains on bottom trawlers. ...
The flapper skate, Dipturus intermedius (Parnell, 1837), is the largest of all European skate and rays (Superorder: Batoidea). It is found in coastal waters of the European continental shelf and slopes in the North-East (NE) Atlantic. With the 2006 IUCN Red List of Threatened Species classification of ‘common skate’ as Critically Endangered, and the recognition in 2010 that this name masked two species (flapper skate and blue skate D. batis (Linnaeus, 1758)), and to better support conservation on this regional scale, the Flapper Skate Working Group (SWG) was formed. The SWG is a consortium of government, NGOs, sport-fishing associates and academics, including participants from the UK, Ireland and the Netherlands. The purpose of the SWG is to consolidate relevant research, advocacy and policy expertize for the purpose of flapper skate conservation. The first SWG workshop took place in Belfast, November 2019, with discussions focussed on conservation in the NE Atlantic. Following two days of talks, workshops and discussions, we present the SWG’s key recommendations for future collaborative conservation.
... Developing effective bycatch mitigation strategies requires actions that maintain target catch and reduce nontarget captures. Recent bycatch mitigation strategies include spatial and temporal fishing restrictions (Lewison et al. 2004;Senko et al. 2014) and modified fishing gear (Werner et al. 2006), such as turtle-excluder devices for shrimp trawls (Crowder et al. 1995;Jenkins 2011) and circle hooks for longline fisheries (Watson et al. 2005;Serafy et al. 2012). ...
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The growing demand for fish around the world is an immediate threat to marine megafauna that are unintentionally captured in commercial and artisanal fishery operations. Bycatch mitigation strategies, such as turtle excluder devices, circle hooks, and net illumination, have successfully reduced this risk in some fisheries. We explored the effectiveness of gillnet illumination to reduce sea turtle captures in 2 artisanal fisheries (Mankoadze and Winneba, Ghana) under normal fishing conditions. We first quantified sea turtle bycatch in Ghana's artisanal gillnet fishery from 15 boats for 12 months. We then quantified catch of targeted species and sea turtle bycatch from 20 boats for 15 months (7427 net sets). For 10 of these boats, we placed a Centro Economy green light (1 LED) at each 10-m interval on the net. We also quantified target catch and sea turtle bycatch from 30 boats for 8 months (2250 net sets). In 15 of these boats, a Centro Deluxe green light (3 LEDs) was installed at 15-m intervals. Boats with economy lights and those with deluxe lights both exhibited an 81% decrease in sea turtle captures (W = 1, p < 0.001, n = 20; W = 215, p < 0.001, n = 30, respectively) compared with control boats without lights. Illuminated nets resulted in fewer turtle catches for leatherback (Dermochelys coriacea), olive ridley (Lepidochelys olivacea), and green sea turtles (Chelonia mydas) (p < 0.05 for all species). Target catch (mass) (W = 53, p = 0.853 n = 20; W = 76, p = 0.449, n = 23) and value (W = 50, p = 1, n = 20; W = 69, p = 0.728, = 23) were not different across treatments. Our study affirms net illumination can reduce capture rates of 3 species of sea turtles, including the imperiled leatherback. Gear modification methods can successfully reduce bycatch if they are affordable and have broad applications for multiple species in different fisheries.
... Much effort has focused on the use of circle hooks in longline fisheries (Gilman et al., 2006;Serafy et al., 2012) and the use of Turtle Excluder Devices (TEDs) in shrimp trawl fisheries (Crowder et al., 1994(Crowder et al., , 1995Watson et al., 2005;Lewison and Crowder, 2006;Read, 2007;Jenkins, 2011). However, the development of bycatch mitigation measures for gillnets, one of the most ubiquitous gear types, has been comparatively slow (Melvin et al., 1999;Gilman et al., 2006). ...
Full-text available
Artisanal gillnet fisheries exist throughout the world’s oceans and have been responsible for high bycatch rates of sea turtles. Three sites on the north coast of Kenya, i.e. Watamu, Ngomeni, and Bwana Said, were studied with the overall objective of assessing the effectiveness of LED lights in the reduction of sea turtle bycatch in the bottom-set gillnet fishery. A total of 10 boats with pairs of control and illuminated nets were deployed during the study, with 56 turtles caught in control nets, while 30 were caught in illuminated nets. The mean catch per unit effort (CPUE) of target species was similar for both control and illuminated nets. In contrast, the mean CPUE of sea turtles was reduced by 64.3% in illuminated nets. This statistically significant decrease (p < 0.04) in sea turtle catch rate suggests that net illumination could be an effective conservation tool. Some useful data on fish catch rates with and without LED lights were also obtained, and interviews with fishermen suggested that they believe that the lights are effective at reducing marine turtle bycatch in their gill nets when set at night. The issues associated with implementing the use of LED lights included increased net handling times, equipment costs, and limited awareness among fishermen regarding the effectiveness of this technology. These challenges need the support of other stakeholders, especially national government, so as to implement this strategy of reducing turtle bycatch more widely. Keywords: mortality; sea turtles; bycatch; small-scale fisheries; gillnet; LED lights
Sea turtles that have entered the submerged bag net of setnets repeatedly push their heads up against the ceiling netting (referred to here as push-ups) to ascend to breathe. Consecutive push-ups are essential to the success of escaping in a turtle releasing system developed to reduce the incidental death in setnets. Existence of differences in behavioral characteristics were suggested among turtle species, but no detailed evaluation has been performed. The objectives of this study were to establish extraction methods of the consecutive push-ups with a tri-axial acceleration logger, and to clarify the differences in the behavioral characteristics between green Chleonia mydas and loggerhead Caretta caretta turtles under the simulated condition of bycatch in setnets for appropriate adaptation and modification of this system. The behavior of each turtle mounted with an acceleration logger in an experimental bag net was recorded using a video camera. The consecutive push-ups were extracted by filtering the time-series body angle converted from the static surge acceleration and the overall dynamic body acceleration (ODBA) from the triaxial dynamic acceleration. A threshold of 20° in body angle and 1.0 m/s² in ODBA was detected among 89 % of all consecutive push-ups in green turtles. On the other hand, the ODBA was not adopted as the extract condition in loggerhead turtles, although a threshold of 20° in the body angle detected 93 % correctly. Mode of ODBA (1.0–1.5 m/s²) in the green turtles was larger than that in the loggerhead turtles (0.5–1.0 m/s²) during consecutive push-ups. In contrast, the number and duration of the consecutive push-ups in the green turtles were less than those of loggerhead turtles. Consequently, modifying the gear with a larger inclination angle of the ceiling netting should be considered for the setnets where the bycatch of green turtles dominates.
Full-text available
Management of many species is currently based on an inadequate under- standing of their population dynamics. Lack of age-specific demographic information, particularly for long-lived iteroparous species, has impeded development of useful models. We use a Lefkovitch stage class matrix model, based on a preliminary life table developed by Frazer (1983a), to point to interim management measures and to identify those data most critical to refining our knowledge about the population dynamics of threatened log- gerhead sea turtles (Caretta caretta). Population projections are used to examine the sen- sitivity of Frazer's life table to variations in parameter estimates as well as the likely response of the population to various management alternatives. Current management practices appear to be focused on the least responsive life stage, eggs on nesting-beaches. Alternative protection efforts for juvenile loggerheads, such as using turtle excluder devices (TEDs), may be far more effective.
All five species of sea turtles in continental U.S. waters are protected under the Endangered Species Act of 1973 and the population sizes of all species remain well below historic levels. Shrimp trawling was determined to be the largest source of anthropogenic mortality of many of the species. As a mechanism to reduce the incidental catch of turtles in trawl nets, turtle excluder devices have been required intermittently in the shrimp fishery since 1987, and at all times since 1994. The expanded turtle excluder device (TED) regulations, implemented in 1994, were expected to reduce shrimp trawl capture of sea turtles by 97%. Recent evidence has indicated that the sizes of turtles stranding were not representative of the animals subjected to being captured by the shrimp trawlers. The purpose of our study was to compare the sizes of stranded sea turtles with the size of the TED openings. We compared the sizes of stranded loggerhead (Caretta caretta), green (Chelonia mydas), and Kemp's ridley (Lepidochelys kempii) sea turtles, the three species most commonly found stranded, to the minimum widths and heights of TED openings. We found that annually a large proportion of stranded loggerhead turtles (33-47%) and a small proportion of stranded green turtles (1-7%) are too large to fit through the required minimum-size TED openings. The continued high mortality of sea turtles caused by bottom trawling is reason for concern, especially for the northern subpopulation of loggerhead turtles, which currently is not projected to achieve the federal recovery goal of reaching and maintaining prelisting levels of nesting.
Hard times and a nickel a bucket: struggle and survival in North Carolina's shrimp industry
  • J R Maiolo
Maiolo, J. R. 2004. Hard times and a nickel a bucket: struggle and survival in North Carolina's shrimp industry. Chapel Hill Press, Inc., N.C., p. 191.
Loggerhead sea turtles, Caretta caretta, encountering shrimp trawls
  • L H Ogren
  • J Watson
  • D A Wickham
Ogren, L. H., J. Watson, and D. A. Wickham. 1977. Loggerhead sea turtles, Caretta caretta, encountering shrimp trawls. Mar. Fish. Rev. 39(11):15-17.
Turtle excluder devices; adoption of alternative scientific testing protocol for evaluation. Notice of adoption
  • Noaa
NOAA. 1990a. Sea turtle conservation; shrimp trawling requirements. Final rule, tech. amendment, 55 FR 195 (9 Oct. 1990), p. 41,088-41,091. ________. 1990b. Turtle excluder devices; adoption of alternative scientific testing protocol for evaluation. Notice of adoption, 55 FR 195 (9 Oct. 1990), p. 41,092-41,093. ________. 1992. Summer flounder fishery. Final rule, 57 FR 234 (4 Dec. 1992), p. 57,358-57,377. ________. 2001a. Sea turtle conservation; shrimp trawling requirements. Interim final rule, 66 FR 93 (14 May 2001), p. 24,290. Available online at https://federalregister. gov/a/01-12081.
notice of proprosed rulemaking
  • Adv
Adv. notice of proprosed rulemaking, 72 FR 31 (15 Feb. 2007), p. 7382-7383. Available online at E7-2719.
Online at by_catch/docs/brep_report_2010.pdf
  • Usdoc
USDOC. 2010. Annual Report to Congress on the Bycatch Reduction Engineering Program U.S. Dep. Commer., NOAA, Natl. Mar. Fish. Serv., 100 p. Online at by_catch/docs/brep_report_2010.pdf ________. 2011. Annual Report to Congress on the Bycatch Reduction Engineering Program. U.S. Dep. Commer., NOAA, Natl. Mar. Fish. Serv., 94 p. Online at www.nmfs. pdf