ArticlePDF Available

The frequency of ingested plastic debris and its effects on body condition of Short-tailed Shearwater (Puffinus tenuirostris) pre-fledging chicks in Tasmania, Australia

Authors:

Abstract and Figures

In recent years, there have been increasing reports of ingestion of marine plastic debris in seabirds. Our aim was to assess the frequency and effects of ingested plastic debris in pre-fledging Short-tailed Shearwaters (Puffinus tenuirostris) in Tasmania. We conducted necropsies of 171 Shearwater chicks, confiscated after illegal poaching, to determine the presence of plastic debris in the proventriculus and ventriculus. We also examined whether there was a correlation between body condition (based on body mass and fat-scores) and quantity of plastic ingested (by count and weight). We recorded 1032 ingested plastic particles, consisting of industrial plastic (31%) and user plastic (69%). Most of the Shearwater chicks (96%) contained plastic debris with a mean of 148.1 mg per bird (s.e. 8.1). Most plastic was found in the ventriculus. Light-coloured plastic dominated (63.8%), with the rest medium (22.1%) and dark (14.1%) plastics. We found that total mass of ingested plastic was not significantly related to body condition, or fat-scores or mass individually. Our study highlights the prevalence of plastic pollution in apparently healthy Shearwater chicks and underscores concern regarding the effects of increasing marine pollution on a global scale.
Content may be subject to copyright.
The frequency of ingested plastic debris and its effects
on body condition of Short-tailed Shearwater (Pufnus
tenuirostris) pre-edging chicks in Tasmania, Australia
Hannah R. Cousin
A,C
, Heidi J. Auman
A
, Rachael Alderman
B
and Patti Virtue
A
A
Institute for Marine and Antarctic Studies, University of Tasmania, Private Bag 129, Hobart, Tas. 7001, Australia.
B
Department of Primary Industries, Parks, Water and Environment, GPO Box 44, Hobart, Tas. 7001, Australia.
C
Corresponding author. Email: hrcousin@utas.edu.au, hancuz@bigpond.com
Abstract. In recent years, there have been increasing reports of ingestion of marine plastic debris in seabirds. Our aim was
to assess the frequency and effects of ingested plastic debris in pre-edging Short-tailed Shearwaters (Pufnus tenuirostris)
in Tasmania. We conducted necropsies of 171 Shearwater chicks, conscated after illegal poaching, to determine the
presence of plastic debris in the proventriculus and ventriculus. We also examined whether there was a correlation between
body condition (based on body mass and fat-scores) and quantity of plastic ingested (by count and weight). We recorded 1032
ingested plastic particles, consisting of industrial plastic (31%) and user plastic (69%). Most of the Shearwater chicks (96%)
contained plastic debris with a mean of 148.1 mg per bird (s.e. 8.1). Most plastic was found in the ventriculus. Light-coloured
plastic dominated (63.8%), with the rest medium (22.1%) and dark (14.1%) plastics. We found that total mass of ingested
plastic was not signicantly related to body condition, or fat-scores or mass individually. Our study highlights the prevalence
of plastic pollution in apparently healthy Shearwater chicks and underscores concern regarding the effects of increasing
marine pollution on a global scale.
Additional keywords: industrial plastic, marine debris, nurdles, plastic colour, plastic pollution, user plastic.
Received 9 September 2013, accepted 9 August 2014, published online 2 February 2015
Introduction
Scientists have documented the effects of plastic pollution on
wildlife since the 1920s (Gudger 1922), with many reports of
effects on marine mammals, seabirds and marine reptiles (Carr
1987; Fowler 1987; Bjorndal et al.1994; Henderson 2001; Cadée
2002; Auman et al.2003; Page et al.2004; Gilman et al.2010;
Carey 2011a). An increasing number of polypropylene- and
polyethylene-based plastic particles, in the form of pre-produc-
tion pellets, known as industrial plastic or nurdles, and fragments
of manufactured plastics, known as user plastic, have been
detected in the marine environment (Rios et al.2007). Because
their size and colour may appear similar to prey species, marine
wildlife may misidentify both nurdles and user-plastic debris as
prey and ingest them accidentally. As the demand for plastic
products increases, particularly for disposable and single-use
items, more debris is likely to inltrate rivers and oceans (Rios
et al.2007; Barnes et al.2009).
Plastic particles are not only being ingested directly by surface
feeding but also via secondary predation in the food web. Studies
also suggest that ingestion of plastic is more of an inter-gener-
ational event than a singular occurrence, with plastic debris being
transferred to the next generation through parental feeding
(Auman et al.1997; Barbieri 2009; Boerger et al.2010; Carey
2011a).
Procellariformes are likely to ingest plastic owing to their
foraging strategies. Many larger species feed by surface-seizing
(Ryan and Jackson 1987; Auman et al. 1997,2003; Ryan 2008;
Barbieri 2009; Avery-Gomm et al.2012) whereas smaller species
are pursuit feeders (Prince et al.1994; Hedd et al.1997; Huin and
Prince 1997). Several species of shearwater have been recorded
with plastic in their digestive systems, including Wedge-tailed
(Ardenna pacica), Sooty (Pufnus griseus), Manx (P. pufnus),
Great (P. gravis) and Short-tailed (P. tenuirostris) Shearwaters
(Furness 1983,1985; Vlietstra and Parga 2002; Pierce et al.2004;
Barbieri 2009; Carey 2011a; Tanaka et al.2013; Verlis et al.
2013). The incidence of plastic ingestion in Short-tailed Shear-
waters is one of the highest reported in seabirds (Vlietstra and
Parga 2002).
The Short-tailed Shearwater is an abundant burrow-nesting
species that breeds solely within Australia, mainly on small
islands of Tasmania, and which undertakes a circum-Pacic
migration (Skira 1986; Wooller et al.1990; Bradley et al.
1991). The species is reasonably well studied, with some colonies
studied since 1947 (Bradley et al.1991). Short-tailed Shearwaters
typically breed annually. They begin breeding from 58 years of
age and may live for 30 years or more (Wooller et al.1990).
A single egg is laid in November, chicks hatch in January and
have a rearing period of ~2.5 months before edging in early April
CSIRO PUBLISHING
Emu,2015, 115,611
http://dx.doi.org/10.1071/MU13086
Journal compilation BirdLife Australia 2015 www.publish.csiro.au/journals/emu
(Serventy and Curry 1984; Wooller et al.1990; Yamashita et al.
2011). During the breeding period (NovemberApril), the for-
aging range of adult Shearwaters extends from coastal Tasmania
to Antarctic waters (Weimerskirch and Cherel 1998; Carey
2011b; Einoder et al. 2011). During the austral summer, prey
includes both Australian and Antarctic euphausiids as well as sh,
squid and other crustacean species (Hamer et al.1997; Weimers-
kirch and Cherel 1998; Vlietstra and Parga 2002). During the non-
breeding period (MaySeptember), they travel to the North
Pacic Ocean, venturing into the subarctic Bering Sea (Vlietstra
and Parga 2002). Because of their abundance, extensive distri-
bution and frequency of recorded plastic ingestion, Short-tailed
Shearwaters are an ideal indicator species for plastic accumula-
tion in the oceans (Vlietstra and Parga 2002; Avery-Gomm et al.
2012).
Previous studies of ingestion of plastic debris in Procellar-
iiformes have used beachcast birds, for which the cause of death
could not be established and carcasses could not therefore be
considered a healthy subset of the population (Pierce et al.2004;
Barbieri 2009; Carey 2011a). These studies could not, therefore,
determine links between plastic ingestion and health. In our study,
we aimed to determine the amount and frequency of plastic
debris in a large, random sample of healthy pre-edging Short-
tailed Shearwaters and then investigated whether this affected
their body condition.
Methods
Location
We obtained a sample of 171 Short-tailed Shearwater chicks from
the Clifton Beach colony (425902200S, 1473101800 E), a coastal
reserve 25 km south-east of Hobart, Tasmania, Australia. Fresh
carcasses taken in opportunistic illegal harvesting were seized by
the Tasmanian Department of Primary Industries, Parks, Water
and Environment in April 2012. Considering the body-weights
(146698 g) and extent of downy plumage moult (095%), we
estimated that the chicks were 37 weeks before edging at the
time of collection (Oka 1989), and therefore deemed them as a
random and healthy sample from the breeding colony.
Dissection
Birds were stored in a freezer at 20C before dissection in
March 2013. Necropsies followed methods outlined in Auman
et al. (1997). We measured wing-chord, percentage of downy
plumage and total body-weight to examine any differences in
morphometric traits that might correlate with the presence and
mass of plastic in birds. Weight was measured on a Masscal scale
(model 323, accuracy 1 g). In cases where carcasses were
beheaded (n= 53), we weighed individual heads of the remaining
chicks and added the average mass to the decapitated specimens.
Wing-chord was measured with a ruler from metacarpal joint to
the end of the tenth primary. We made a visual estimate of the
percentage of downy plumage on the dorsal (including head and
neck) and ventral (including chin and throat), with each side 50%
of the total coverage of downy plumage.
Using surgical scissors, a small horizontal incision was made
just above the cloaca on the ventral side of the body. A cut was
then made up the chest cavity, from posterior to anterior, to access
the digestive tract.
We estimated a pectoral muscle-score of 03 (0, no muscle; 1,
low levels of muscle; 2, moderate levels of muscle; 3, well
muscled) and a fat-score of 03 (as muscle-score, with 0 = no
fat to 3 = high fat) of both subcutaneousand visceral fat, following
methods of van Franeker (2004). The digestive system was
removed for easier analysis with one cut made just above the
cloaca and a second just under the caudal tip of the heart muscle,
cutting ventrally through the oesophagus. Upon extraction of the
digestive tract, observations were made on the condition of the
liver, heart and lungs; any sign of discolouration or haemorrha-
ging was noted.
Protocol for plastic sampling
Previous studies on seabirds have sampled only the proventric-
ulus and ventriculus; to obtain comparable results, we followed
this protocol, which aligned with the methods of Auman et al.
(1997). These two sections of the stomach were assessed
separately; contents of each were washed with fresh water and
air-dried in a Petri dish. Following Auman et al. (1997), the
proventricular lining was examined for any perforations or
lacerations that may have been caused by the ingested plastic
fragments.
The contents of the proventriculus and ventriculus were
weighed with a Mettler Toledo balance (accuracy 0.0001 g).
Samples were categorised as organic matter, plastics and prey
items. Plastics were then categorised as industrial plastic, user
plastic or other, following Ogi (1990), Vlietstra and Parga (2002)
and Carey (2011a) to allow comparison between this and previ-
ous studies. To determine the prevalence of various colours of
plastics, we initially followed the classications of colour of
Vlietstra and Parga (2002) and Carey (2011a). However, because
many pieces of plastic did not match these colour categories, we
added 11 colours to the classication: clear, white-yellow, peach,
light green, light blue and pink were added to the light colour
category; orange, olive-green and turquoise were added to the
medium category; and dark grey and dark red-brown were added
to the dark category.
Statistical analyses
Statistical analyses were conducted in R version 2.14.2 (R
Development Core Team 2011) and signicance level for all
tests was set at a<0.05. Both non-parametric and parametric tests
were used to assess statistical signicance between morphometric
measurements and plastic loads. Pearsons Chi-square test with
Yates continuity correction and log-likelihood ratios (non-
parametric) were used as a precursor to any signicance (Vlietstra
and Parga 2002; Yamashita et al.2011), which was later tested
and veried with an analysis of variance (ANOVA) (parametric).
Results
Of the 171 birds, 96% had ingested plastic debris, with a mean
plastic mass of 148.1 mg per bird (s.e. 8.1 mg) or 155.4mg per
bird containing plastic (s.e. 8.0). Seven birds had no plastic within
either the proventriculus or ventriculus. A total of 1032 pieces of
plastic was collected, weighing 25.32 g. On average, each bird
contained 6.03 0.3 (s.e.) pieces of plastic, with a range of 130
plastic pieces per bird. Mean body-mass was 503.2 g 6.94 g s.e.
(range 146698 g), mean wing-chord 26.7 cm 0.09 cm s.e.
Effects of plastic ingestion on body condition Emu 7
(range 21.529.0 cm) and mean percentage of downy plumage
was 31% 2.0% s.e. (range 095%).
The most abundant type of plastic, by number of fragments,
was user plastic (68.9%) followed by industrial plastic nurdles
(31.0%),with little other plastic (one rubber O-ring) (0.09%)
(Table 1). The majority of plastic debris was found in the
ventriculus (89%, or 924 pieces) (Table 1). The largest number
of plastic fragments found within one bird was 30 pieces, all in
the ventriculus (11 industrial and 19 user). The retrieved plastic
included rounded and worn, irregular and sharp-edged fragments
ranging in length from 1 to 20 mm.
In terms of light, medium and dark colours, light-coloured
plastic (63.76%) was most prevalent, followed by medium col-
ours (22.09%) and dark colours (14.15%) (Table 2). Of the
individual colours identied, yellow-brown (23.06%), white-
yellow (16.47%) and brown (13.18%) were the most commonly
ingested (Table 2).
There was no correlation between total mass of plastic
ingested and any of the morphometric traits measured: body
mass (P= 0.642), wing-chord (P= 0.599) or percentage of downy
plumage (P= 0.469). On average, the edglings had high scores
(3) for both subcutaneous and visceral fat and also for pectoral
muscle. There was also no correlation between total mass of
plastic and either pectoral muscle-score (P= 0.756) or subcuta-
neous fat-score (P= 0.342). Although not statistically signicant,
a weak correlation between ingested plastic load and visceral fat-
score (P= 0.0967) is suggestive of a link between the amount of
plastic ingested and visceral fat around the intestine (Fig. 1).
Body-mass was positively correlated with pectoral muscle-
score, and subcutaneous and visceral fat-scores (all P<0.001).
Table 1. Number and proportion of each type of plastic in the proventriculus and ventriculus of edgling Short-tailed Shearwaters (total = 1032 pieces)
Industrial plastic User plastic Other plastic
Proventriculus Ventriculus Proventriculus Ventriculus Proventriculus Ventriculus
Number of pieces 18 302 89 622 1 0
Proportion of total (%) 1.7% 29.2% 8.6% 60.2% 0.09% 0%
Overall proportion of each type of plastic 31.0% 68.9% 0.09%
Table 2. Number and proportion of plastic particles of different colour
in the proventriculus and ventriculus of Short-tailed Shearwater chicks
Colour Number of pieces %
Light
Clear 9 0.87
White 101 9.79
White-yellow 170 16.47
Yellow 78 7.56
Yellow-brown 238 23.06
Peach 4 0.39
Light green 44 4.26
Light blue 3 0.29
Grey 10 0.97
Pink 1 0.09
Sub-total 658 63.76
Medium
Brown 136 13.18
Blue 4 0.39
Orange 16 1.55
Green 12 1.16
Olive-green 15 1.45
Red 19 1.84
Turquoise 26 2.52
Sub-total 228 22.09
Dark
Dark grey 5 0.48
Dark blue 1 0.09
Dark green 17 1.65
Dark red 10 0.97
Dark red-brown 61 5.91
Black 52 5.04
Sub-total 146 14.15
Total 1032 100
0.6 (a)
(b)
(c)
0.4
0.2
0
012
Pectoral muscle-score
Subcutaneous fat-score
Visceral fat-score
3
0123
0123
0.6
0.4
Ingested plastic load (g)
0.2
0
0.6
0.4
0.2
0
Fig. 1. Relationship between plastic load (weight of plastic (g)) and:
(a) pectoral muscle-score; (b) subcutaneous fat-score; and (c) visceral fat-
score. Muscle and fat were scored from 0 to 3: 0, no muscle or fat; 1, low levels
of muscle or fat; 2, moderate levels of muscle or fat; 3, high levels of muscle or
fat. Box-plots show the range of plastic loads, and black dots the median
weight of plastic weight in each fat score.
8Emu H. R. Cousin et al.
Wing-chord and percentage of downy plumage were strongly
positively correlated with body-mass (P<0.001).
In addition to plastic, other gut contents in the proventriculus
and ventriculus included wood, stones, squid beaks and a rarely
found isopod, Anuropus sp. (family Anaropidae; G. Poore and
N. Bruce, pers. comm., 2013).
Discussion
Observations of wildlife casualties from entanglement in and
ingestion of plastic debris are increasing around the world. Sea-
birds in particular are facing greater exposure to this threat as
levels of marine plastic pollution increase (Barnes et al.2009).
Short-tailed Shearwaters are one species of seabird that could be
exposed to this increasing threat, owing to their foraging range
spanning the northern and southern hemispheres and several
oceans. The results of our study, reporting a 96% incidence of
plastic-debris ingestion in Short-tailed Shearwater chicks from a
reasonably remote area and before they edge, are a signicant
concern, particularly in the context of global marine pollution.
The results of our study are comparable to those of Carey
(2011a) on Phillip Island, Victoria. Those beachcast Short-tailed
Shearwater edglings had ingested an average 113 mg of plastic
per bird compared with our Tasmanian pre-edging chicks with
148 mg per bird. We also found, as did Carey (2011a), that user
plastic was the most commonly ingested plastic, with the
majority of the plastic particles located in the ventriculus and a
high proportion of light-coloured plastic debris ingested. Adult
Short-tailed Shearwaters in the Bering Sea (Vlietstra and Parga
2002) had similar plastic loads, of 6.9 pieces per bird compared
with the 6.0 pieces per bird of our study.
Given the extensive foraging range of this species and the fact
that the retention time of plastics in seabirds is poorly understood,
but may be 6 months or more (Day et al.1985; Ryan 1989), it is
not possible to say whether the plastic debris in this study was
ingested in local Tasmanian or more distant waters. Previous
studies have shown that adults do forage around southern Aus-
tralia and into Antarctic waters during the breeding season, with
foraging trips averaging 12 days (Weimerskirch and Cherel
1998; Carey 2011b; Einoder et al. 2011). It is therefore likely that
the Clifton Beach chicks are receiving plastics from the southern
hemisphere (Raymond et al.2010).
Short-tailed Shearwaters are considered an ideal indicator
species of plastic accumulation in the oceans (Vlietstra and Parga
2002; Avery-Gomm et al.2012). Although 96% of the chicks in
this study contained plastic debris, we found no evidence that
plastic ingestion was effecting the physical health of Shearwater
chicks from this Tasmanian population. The natural diet of these
birds includes squid beaks and sh bones so their digestive system
is likely to be robust enough to cope with sharp objects. Given
the exibility of the proventriculus and ventriculus, we would not
expect to nd obvious perforations resulting from small pieces of
plastic. No statistically signicant correlations between plastic
load and body condition were observed, nor were there any
reductions in body fat or mass of these birds that could be
contributed to ingested plastic. Additionally, the proventricular
linings of the 171 fresh carcasses showed no punctures, lacera-
tions or ulcerations potentially owing to ingested plastic debris.
Given the rather small amounts of plastic in each bird and their
normal diet including squid this is not surprising. No deaths have
been directly attributed to proventricular damage in several
hundred freshly dead Laysan Albatross necropsied between
1993 and 2000, and this species is reported to have the heaviest
plastic loads of all seabirds (Auman et al. 1997; H. J. Auman, pers.
obs.).
Analyses of plastic items ingested by seabirds often show a
non-random selection, presumably because they match the col-
ours of their prey (Ryan 1987; Cooper et al.2004). The prevalence
of light colours, particularly white, white-yellow, yellow-brown
and brown found in Short-tailed Shearwaters resembles prey
species found in the North Pacic Ocean, in particular the
euphausiids (Vlietstra and Parga 2002). Although the numbers
of white plastic pieces reported here are lower than those found
in birds from the Bering Sea (Vlietstra and Parga 2002), there
appears to be a greater proportion of yellow-brown plastics in
birds in waters around Tasmania. This shift in colour predomi-
nance could be a result of a change in prey species closer to
breeding grounds. However, some staining of plastic fragments
within the digestive system of the birds is also possible.
Owing to the various chemicals added to plastics during their
production, there is some risk of toxicological effects from
ingesting plastics, because it has been suggested that chemicals
derived from plastics may leach from ingested plastic into seabird
tissues. Polybrominated diphenyl ethers (PBDE) congeners,
originating in ame retardants, have been found in Short-tailed
Shearwater adipose tissue yet not found in their prey items
(Tanaka et al.2013). Polychlorinated biphenyls (PCB) have been
positively correlated with ingested plastics in at least eight species
of Procellariiformes (Ryan et al.1988; Colabuono et al.2010).
Potential toxicological effects as a result of ingested plastics are
still being elucidated and the effects of many contaminants,
including heavy metals, on seabirds are currently not known
(Yamashita et al.2011). We recommend future research on the
toxicological effects of plastics to discern the long-term effects of
ingested plastic debris on seabird populations.
Acknowledgements
This research project was conducted under the Tasmanian Department of
Primary Industries, Parks, Water and Environment (DPIPWE) permit number
TFA13039. Gratitude goes to laboratory assistants Skye-Louise Lawler,
Tamara Bartholomew, Natalie Bool, Marion Foucher and Nicole Hellessey.
Thanks also to Kris Carlyon for facilitating the collection of the Shearwaters
from the DPIPWE, Simon Witherspoon and Mark Hindell for their statistical
advice, Kerry Swadling, and Gary Poore and Niel Bruce (Museum Victoria,
Melbourne) for identication of the unknown isopod. We also thank two
reviewers who improved this manuscript.
References
Auman, H. J., Ludwig, J. P., Giesy, J. P., and Colborn, T. (1997). Plastic
ingestion by Laysan Albatross chicks on Sand Island, Midway Atoll,
in 1994 and 1995. In Albatross Biology and Conservation. (Eds
G. Robinson and R. Gales.) pp. 239244. (Surrey Beatty and Sons:
Sydney.)
Auman, H. J., Woehler, E. J., Riddle, M. J., and Burton, H. (2003). First
evidence of plastic debris ingestion in Heard Island seabirds. Marine
Ornithology 32, 105106.
Avery-Gomm, S., OHara, P. D., Kleine, L., Bowes, V., Wilson, L. K., and
Barry, K. L. (2012). Northern Fulmars as biological monitors of trends of
Effects of plastic ingestion on body condition Emu 9
plastic pollution in the eastern North Pacic. Marine Pollution Bulletin 64,
17761781. doi:10.1016/j.marpolbul.2012.04.017
Barbieri, E. (2009). Occurrence of plastic particles in procellariiforms, south
of Sao Paulo State (Brazil). Brazilian Archives of Biology and Technology
52, 341348. doi:10.1590/S1516-89132009000200011
Barnes, D. K. A., Galgani, F., Thompson, R. C., and Barlaz, M. (2009).
Accumulation and fragmentation of plastic debris in global environments.
Philosophical Transactions of the Royal Society B. Biological Sciences
364, 19851998. doi:10.1098/rstb.2008.0205
Bjorndal, K. A., Bolten, A. B., and Lagueux, C. J. (1994). Ingestion of marine
debris by juvenile sea turtles in coastal Florida habitats. Marine Pollution
Bulletin 28, 154158. doi:10.1016/0025-326X(94)90391-3
Boerger, C. M., Lattin, G. L., Moore, S. L., and Moore, C. J. (2010). Plastic
ingestion by planktivorous shes in the North Pacic Central Gyre.
Marine Pollution Bulletin 60, 22752278. doi:10.1016/j.marpolbul.
2010.08.007
Bradley, J. S., Skira, I. J., and Wooller, R. D. (1991). A long-term study of
Short-tailed Shearwaters Pufnus tenuirostris on Fisher Island, Australia.
Ibis 133,5561. doi:10.1111/j.1474-919X.1991.tb07669.x
Cadée, G. C. (2002). Seabirds and oating plastic debris. Marine Pollution
Bulletin 44, 12941295. doi:10.1016/S0025-326X(02)00264-3
Carey, M. J. (2011a). Intergenerational transfer of plastic debris by Short-
tailed Shearwaters (Ardenna tenuirostris). Emu 111, 229234.
doi:10.1071/MU10085
Carey, M. J. (2011b). Incubation routine, duration of foraging trips and
regulation of body mass in Short-tailed Shearwaters (Ardenna tenuiros-
tris). Emu 111, 166171. doi:10.1071/MU10043
Carr, A. (1987). Impact of nondegradable marine debris on the ecology and
survival outlook of sea turtles. Marine Pollution Bulletin 18, 352356.
doi:10.1016/S0025-326X(87)80025-5
Colabuono, F. I., Taniguchi, S., and Montone, R. C. (2010). Polychlorinated
biphenyls and organochlorine pesticides in plastics ingested by seabirds.
Marine Pollution Bulletin 60, 630634. doi:10.1016/j.marpolbul.2010.
01.018
Cooper, J., Auman, H. J., and Klavitter, J. (2004). Do the albatrosses of
Midway Atoll select cigarette lighters by color? Pacic Seabirds 31,24.
Day, R. H., Wehle, D. H. S., and Coleman, F. C. (1985). Ingestion of plastic
pollutants by marine birds. In Proceedings of the Workshop on the Fate
and Impact of Marine Debris,2729 November 1984, Honolulu, Hawaii.
(Eds R. S. Shomura and H. O. Yoshida) NOAA Technical Memorandum
NOAA-TM-NMFS-SWFC-54, pp. 344386. (National Oceanic and
Atmospheric Administration, US Department of Commerce) Available
at http://www.st.nmfs.noaa.gov/tm/swfc/swfc054.pdf [Veried 11
November 2014]
Einoder, L. D., Page, B., Goldsworthy, S. D., De Little, S. C., and Bradshaw,
C. J. A. (2011). Exploitation of distant Antarctic waters and close neritic
waters by Short-tailed Shearwaters breeding in South Australia. Austral
Ecology 36, 461475. doi:10.1111/j.1442-9993.2010.02176.x
Fowler, C. W. (1987). Marine debris and Northern Fur Seals: a case study.
Marine Pollution Bulletin 18, 326335. doi:10.1016/S0025-326X(87)
80020-6
Furness, B. L. (1983). Plastic particles in three procellariiform seabirds from
the Benguela Current, South Africa. Marine Pollution Bulletin 14,
307308. doi:10.1016/0025-326X(83)90541-6
Furness, R. W. (1985). Plastic particles pollution: accumulation by procellarii-
form seabirds at Scottish colonies. Marine Pollution Bulletin 16, 103106.
doi:10.1016/0025-326X(85)90531-4
Gilman, E., Gearhart, J., Price, B., Eckert, S., Milliken, H., Wang, J.,
Swimmer, Y., Shiode, D., Abe, O., Peckham, S. H., Chaloupka, M., Hall,
M., Mangel, J., Alfaro-Shigueto, J., Dalzell, P., and Ishizaki, A. (2010).
Mitigating sea turtle by-catch in coastal passive net sheries. Fish and
Fisheries 11,5788. doi:10.1111/j.1467-2979.2009.00342.x
Gudger, E. W. (1922). Foreign bodies found embedded in the tissues of shes.
Natural History 22, 452457.
Hamer, K. C., Nicholson, L. W., Hill, J. K., Wooller, R. D., and Bradley, J. S.
(1997). Nestling obesity in procellariiform seabirds: temporal and
stochastic variation in provisioning and growth of Short-tailed Shear-
waters Pufnus tenuirostris. Oecologia 112,411. doi:10.1007/
s004420050276
Hedd, A., Gales, R., Brothers, N., and Robertson, G. (1997). Divingbehaviour
of the Shy Albatross Diomedea cauta in Tasmania: initial ndings and
dive recorder assessment. Ibis 139, 452460. doi:10.1111/j.1474-919X.
1997.tb04658.x
Henderson, J. R. (2001). A pre and post-MARPOL Annex V summary of
Hawaiian Monk Seal entanglements and marine debris accumulation in
the north-western Hawaiian Islands, 19821998. Marine Pollution Bul-
letin 42, 584589. doi:10.1016/S0025-326X(00)00204-6
Huin, N., and Prince, P. A. (1997). Diving behaviour of the Grey-headed
Albatross. Antarctic Science 9, 243249. doi:10.1017/S0954102097
000321
Ogi, H. (1990). Ingestion of plastic particles by Sooty and Short-tailed
Shearwaters in the North Pacic. In Proceedings of the Second Interna-
tional Conference on Marine Debris,27 April 1989, Honolulu, HI.
(Eds R. S. Shomura, M. L. Godfrey) NOAA Technical Memorandum,
pp. 635652. (National Oceanic and Atmospheric Administration, US
Department of Commerce: Honolulu, HI.)
Oka, N. (1989). Chick growth and development of the Short-tailed Shearwater
Pufnus tenuirostris in Tasmania. Journal of the Yamashina Institute for
Ornithology 21, 193207. doi:10.3312/jyio1952.21.193
Page, B., McKenzie, J., McIntosh, R., Baylis, A., Morrissey, A., Calvert, N.,
Haase, T., Berris, M., Dowie, D., Shaughnessy, P. D., and Goldsworthy,
S. D. (2004). Entanglement of Australia Sea Lions and New Zealand Fur
Seals in lost shing gear and other marine debris before and after
government and industry attempts to reduce the problem. Marine Pollu-
tion Bulletin 49,3342. doi:10.1016/j.marpolbul.2004.01.006
Pierce, K. E., Harris, R. J., Larned, L. S., and Pokras, M. A. (2004).
Obstruction and starvation associated with plastic ingestion in a Northern
Gannet Morus bassanus and a Greater Shearwater Pufnus gravis. Marine
Ornithology 32, 187189.
Prince, P. A., Huin, N., and Weimerskirch, H. (1994). Diving depths of
albatrosses. Antarctic Science 6, 353354. doi:10.1017/S0954102094
000532
R Development Core Team (2011). R: A Language and Environment for
Statistical Computing.(R Foundation for Statistical Computing: Vienna,
Austria.) Available at http://www.R-project.orgs [Veried 28 May 2013].
Raymond, B., Shaffer, S. A., Sokolov, S., Woehler, E. J., Costa, D. P.,
Einoder, L., Hindell, M., Hosie, G., Pinkerton, M., Sagar, P. M., Scott, D.,
Smith, D., Thompson, D. R., Vertigan, C., and Weimerskirch, H. (2010).
Shearwater foraging in the Southern Ocean: the roles of prey availability
and winds. PLoS ONE 5(6), e10960. doi:10.1371/journal.pone.0010960
Rios, L. M., Moore, C., and Jones, P. R. (2007). Persistent organic pollutants
carried by synthetic polymers in the ocean environment. Marine Pollution
Bulletin 54, 12301237. doi:10.1016/j.marpolbul.2007.03.022
Ryan, P. G. (1987). The incidence and characteristics of plastic particles
ingested by seabirds. Marine Environmental Research 23, 175206.
doi:10.1016/0141-1136(87)90028-6
Ryan, P. G. (1989). The effects of ingested plastic and other marine debris
on seabirds. In Proceedings of the Second International Conference on
Marine Debris,27 April 1989, Honolulu, HI. (Eds R. S. Shomura,
M. L. Godfrey) NOAA Technical Memorandum, pp. 623634. (National
Oceanic and Atmospheric Administration, US Department of Commerce:
Honolulu, HI.)
Ryan, P. G. (2008). Seabirds indicate changes in the composition of plastic
litter in the Atlantic and south-western Indian Oceans. Marine Pollution
Bulletin 56, 14061409. doi:10.1016/j.marpolbul.2008.05.004
10 Emu H. R. Cousin et al.
Ryan, P. G., and Jackson, S. (1987). The lifespan of ingested plastic particlesin
seabirds and their effect on digestive efciency. Marine Pollution Bulletin
18, 217219. doi:10.1016/0025-326X(87)90461-9
Ryan, P. G., Connell, A. D., and Gardner, B. D. (1988). Plastic ingestion and
PCBS in seabirds: is there a relationship? Marine Pollution Bulletin 19,
174176. doi:10.1016/0025-326X(88)90674-1
Serventy, D. L., and Curry, P. J. (1984). Observations on colony size, breeding
success, recruitment and inter-colony dispersal in a Tasmanian colony of
Short-tailed Shearwaters Pufnus tenuirostris over a 30 year period. Emu
84(2), 7179. doi:10.1071/MU9840071
Skira, I. J. (1986). Food of the Short-tailed Shearwater, Pufnus tenuirostris,
in Tasmania. Australian Wildlife Research 13, 481488. doi:10.1071/
WR9860481
Tanaka, K., Takada, H., Yamashita, R., Mizukawa, K., Fukuwaka, M., and
Watanuki, Y. (2013). Accumulation of plastic-derived chemicals in
tissues of seabirds ingesting marine plastics. Marine Pollution Bulletin
69, 219222. doi:10.1016/j.marpolbul.2012.12.010
van Franeker, J.A. (2004). Save the North Sea Fulmar-Litter-EcoQO Manual.
Part 1: Collection and dissection procedures. Alterra Report 672. Alterra,
Wageningen, The Netherlands. Available at http://edepot.wur.nl/40451
[Veried 15 March 2013].
Verlis, K. M., Campbell, M. L., and Wilson, S. P. (2013). Ingestion of marine
debris plastic by the Wedge-tailed Shearwater (Ardenna pacica) in the
Great Barrier Reef, Australia. Marine Pollution Bulletin 72, 244249.
doi:10.1016/j.marpolbul.2013.03.017
Vlietstra, L. S., and Parga, J. A. (2002). Long-term changes in the type, but not
amount, of ingested plastic particles in Short-tailed Shearwaters in the
south-eastern Bering Sea. Marine Pollution Bulletin 44, 945955.
doi:10.1016/S0025-326X(02)00130-3
Weimerskirch, H., and Cherel, Y. (1998). Feeding ecology of Short-tailed
Shearwaters: breeding in Tasmania and foraging in the Antarctic. Marine
Ecology Progress Series 167, 261274. doi:10.3354/meps167261
Wooller, R. D., Bradley, J. S., Skira, I. J., and Serventy, D. L. (1990).
Reproductive success of Short-tailed Shearwaters Pufnus tenuirostris
in relation to their age and breeding experience. Journal of Animal Ecology
59, 161170. doi:10.2307/5165
Yamashita, R., Takada, H., Fukuwaka, M., and Watanuki, Y. (2011). Physical
and chemical effects of ingested plastic debris on Short-tailed Shear-
waters, Pufnus tenuirostris, in the North Pacic Ocean. Marine Pollution
Bulletin 62, 28452849. doi:10.1016/j.marpolbul.2011.10.008
Effects of plastic ingestion on body condition Emu 11
www.publish.csiro.au/journals/emu
... Neben direkten Auswirkungen wie z. B. das Verfangen von Meeressäugern, Schildkröten und Seevögeln in Plastiknetzen oder -schlingen (Croxall et al., 1990;Arnould & Croxall, 1995;Gregory, 2009;Phillips et al., 2010;Votier et al., 2011;Duncan et al., 2017;Franco-Trecu et al., 2017) sowie das Verschlucken von Plastikpartikeln (Moser & Lee, 1992;Pierce et al., 2004;Gregory, 2009;Brandão et al., 2011;Kühn & van Franeker, 2012;Schuyler et al., 2012;Codina-García et al., 2013;Cole et al., 2013;de Stephanis et al., 2013;Bond et al., 2014;Cousin et al., 2015;Lusher et al., 2015;Gilbert et al., 2016;Denuncio et al., 2017;van Franeker et al., 2018) sind auch indirekte negative Auswirkungen durch enthaltende bzw. anhaftende Schadstoffe zu erwarten (z. ...
... Daten A. Nordt, ergänzt) Quelle: eigene Darstellung, Institut für Ökologie und Evolution, Friedrich-Schiller-Universität Jena Intergenerationeller Transfer von Mikroplastik wurde bereits für mehrere Vertreter der Ordnung der Procellariiformes der Südhemisphäre nachgewiesen, so z. B. für Buntfußsturmschwalbe, Südlicher Riesensturmvogel, Sepiasturmtaucher (Calonectris diomedea) oder Kurzschwanzsturmtaucher (Ardenna tenuirostris) (van Franeker & BellCopello & Quintana, 2003;Carey, 2011;Rodríguez et al., 2012;Cousin et al., 2015). ...
Technical Report
Full-text available
Antarctica and the surrounding Southern Ocean are under increasing pressure from cumulative impacts of climate change, pollution, fisheries, tourism and a variety of other human activities. These changes pose a high risk both to local polar ecosystems and to the regulation of the global climate, as well as through global sea-level rise. Thus, long-term monitoring programmes serve to assess the state of ecosystems as well as to make projections for future developments. The Fildes Region in the southwest King George Islands (South Shetland Islands, Maritime Antarctica), consisting of the Fildes Peninsula, Ardley Island and several offshore islands, is one of the largest ice-free areas in the Maritime Antarctic. As a continuation of a long-term monitoring programme started in the 1980s, local breeding bird and seal populations were recorded during the summer months (December, January, February) of the 2018/19 and 2019/20 seasons and supplemented by individual count data for the 2020/21 season. This study presents the results obtained, including the population development of the local breeding birds. Here, some species showed stable populations in a long-term comparison (brown skuas, southern polar skuas) or a significant increase (gentoo penguin, southern giant petrel). Other species, however, recorded significant declines in breeding pair numbers (Adélie penguin, chinstrap cenguin, Antarctic tern, kelp gull) up to an almost complete disappearance from the breeding area (cape petrel). In addition, the number of seals at their haul-out sites was recorded and the distribution of all seal reproduction sites in the Fildes Region was presented. Furthermore, data on the breeding bird population in selected areas of Maxwell Bay were added. Additionally, the rapid expansion of the Antarctic hairgrass was documented with the help of a completed repeat mapping. The documentation of glacier retreat areas of selected areas of Maxwell Bay was updated using satellite imagery and considered in relation to regional climatic development. Furthermore, the distribution and amount of marine debris washed up in the Fildes Region and the impact of anthropogenic material on seabirds will are addressed. In addition, the current knowledge of all introduced non-native species in the study area and the need for further research are presented.
... an increase in the body mass of birds, which could lead to an increase in the duration of feeding activities (Adams et al. 2009;Heggøy et al. 2015). In addition, the colour of plastic plays an essential role in plastic ingestion by marine organisms, such as fish (Egbeocha et al. 2018), sea turtles (Eastman et al. 2020), and seabirds (Cousin et al. 2015;Provencher et al. 2019). Studies have reported that plastics with light colours are ingested by seabirds more than those with dark colours (Verlis et al. 2013;Santos et al. 2016). ...
Chapter
Microplastics (MPs), which are tiny plastic materials with size below 5 mm, are ubiquitous in both terrestrial and aquatic environments. They are an emerging pollutant posing potential threats to the biosphere. Once they get into the environment, microplastic wastes are difficult to eliminate and hence are continually accumulating in the environment resulting in pollution. Eventually, they end up in the food web, and due to their tiny size, they can easily enter bodies of the biosphere. They also can act as conduits for the proliferation of microbes and fungi. Undoubtedly, the MPs waste needs to be handled safely. Understanding the MPs cycle from the point of generation to disposal can help in the safe use of MPs and handling of MPs waste. This chapter, therefore, discusses the MPs cycle by focusing on the generation of MPs, characterisation of MPs and review of the current challenges associated with MPs waste. The current research trends in the area of MPs pollution will be reviewed together with recommendations on future mitigation measures.
... an increase in the body mass of birds, which could lead to an increase in the duration of feeding activities (Adams et al. 2009;Heggøy et al. 2015). In addition, the colour of plastic plays an essential role in plastic ingestion by marine organisms, such as fish (Egbeocha et al. 2018), sea turtles (Eastman et al. 2020), and seabirds (Cousin et al. 2015;Provencher et al. 2019). Studies have reported that plastics with light colours are ingested by seabirds more than those with dark colours (Verlis et al. 2013;Santos et al. 2016). ...
Chapter
The quantity of plastic debris entering the ocean per annum is growing at an alarming rate . Synthetic plastic waste, both macro and microplastics enter the marine environment from fishing, coastal tourism, sea-food and other marine industries, and other plastic products. Plastic pollution has a drastic effect on all aquatic life. The conventional plastics which turn up in seas and oceans are recalcitrant to biodegradation and end up being around for decades and centuries. Marine biota is attracted to plastic due to its colour, odour and through the algae that develop films on floating plastics which is a significant source of food for marine animals. The most obvious and disturbing impact of pollution of the marine ecosystem with macro - plastics is the ingestion, suffocation and subsequent death of hundreds of marine species. Bioremediation is a useful strategy for the control of plastic pollution in water bodies. The microbes which live in the vicinity of plastic waste adapts and grows on the surface of plastic as biofilms. They produce catalytic enzymes which can degrade the plastic. However, the extent of biodegradation of the plastic will depend upon its structure and chemical properties. This chapter deals with the biodegradation of macro-plastic waste utilizing various microbes, and the challenges associated with the approach.
... an increase in the body mass of birds, which could lead to an increase in the duration of feeding activities (Adams et al. 2009;Heggøy et al. 2015). In addition, the colour of plastic plays an essential role in plastic ingestion by marine organisms, such as fish (Egbeocha et al. 2018), sea turtles (Eastman et al. 2020), and seabirds (Cousin et al. 2015;Provencher et al. 2019). Studies have reported that plastics with light colours are ingested by seabirds more than those with dark colours (Verlis et al. 2013;Santos et al. 2016). ...
Chapter
Asia is the largest global plastic consumer, with about 35% of the world’s plastic consumption. Considering that Malaysia is a part of Asia, it is evident that plastic use is extensive. Unfortunately, discarding plastic causes several environmental hazards and affects human wellbeing. The environmental authorities and the government have been organising campaigns that focus on propagating the reduce, recycling, and reuse concept among the Malaysian public. Nevertheless, after considering the extensive presence of microorganisms in the environment and their affinity towards degrading plastic, the use of such microorganisms and enzymes appears an efficacious approach. Environmental degradation of plastic typically happens through five processes: photodegradation, thermo-oxidative breakdown, hydrolytic degradation, mechanical degradation, and microbial degradation. Microbial degradation comprises plastic breakdown by microorganisms, which produce enzymes that can split long-chain polymers. Microbial enzymes are interesting since they are cost-effective and require minimal maintenance; at the same time, they are easy to manipulate. Rhizopus delemar, R. arrhizus, Pseudomonas sp., Penicillium funiculosum, and Aspergillus flavus are the five microbes that have been cited extensively regarding their ability to break down specific plastics. Moreover, fungal, bacterial, cyanobacteria, and actinomycetes capabilities for plastic degradation are among the environmentally friendly techniques that can help the environment. This chapter discussed how cyanobacteria could be used to break down plastics. The projected research outcome is the identification of potent microbial agents that can rapidly degrade plastics with minimal environmental impact. Keywords Biodegradation mechanism Cyanobacteria Plastics Phycoremediation
... The previous research results revealed that microplastic has been causing severe global environmental problems to date (Conchubhair et al., 2019;Wilcox et al., 2015). Plastic has a unique characteristic that is difficult to degrade with harmful content of microplastics, threatening the marine biotic systems (Gall & Thompson, 2015;Seltenrich, 2016) and birds (Cousin et al., 2015;Gilbert et al., 2016). Microplastics enter the food chain starting from zooplankton (Collignon et al., 2012) to organisms at higher trophies such as mussels (Van Cauwenberghe & Janssen, 2014). ...
Article
Full-text available
Plastic debris sized from 0.33 to 5 mm or so-called microplastic is an abundant environmental pollutant found worldwide in various ecosystems. The contamination has been threatening animals such as fish, wild birds, domesticated poultry, and waterfowls. This preliminary research aimed to reveal the evidence of microplastic contamination in domesticated duck to prove that plastic contamination has spread massively and depicts how far the local duck ingests microplastic. Total 25 duck samples were collected from local duck intensive husbandry in five cities, i.e., Semarang and Pati (coastal area), Salatiga (lowland area), and Temanggung and Magelang (highland area). Duck intestinal tract samples were collected and were further digested using 10 N KOH at 60–80 °C for 24 h. The mixture was then collected into vial tubes and was centrifuged to get the pellet. The microplastic identification was conducted using a stereo microscope based on its size and shape. Based on the observation result, microplastic debris in the form of the filament was 49, 39, and 27 per individual in the duck sample from Salatiga, Semarang, and Magelang, respectively. The ingestion of plastic may come from duck feed, such as rough fish (mainly were obtained from the Java Sea) and water. This finding is essential to disseminate since microplastic contamination can be transferred from animals to humans and threaten health. Also, this result can contribute to policymakers deciding on plastic reduction.
... With population estimates between 13.1-16.5 million breeding pairs (Norman et al., 1996), they are the most abundant Procellariformes breeding in Australia (Skira et al., 1986). However, there is little information on POPs levels in this species, with previous contamination studies having focussed on plastic ingestion (Cousin et al., 2015;Tanaka et al., 2013) and metals (Ishii et al., 2017;Lavers and Bond, 2013;Puskic et al., 2020). ...
Article
While globally distributed throughout the world's ecosystems, there is little baseline information on persistent organic pollutants (POPs) in marine environments in Australia and, more broadly, the Southern Hemisphere. To fill this knowledge gap, we collected baseline information on POPs in migratory short-tailed shearwaters (Ardenna tenuirostris) from Fisher Island, Tasmania, and resident little penguins (Eudyptula minor) from Phillip Island, Victoria. Levels of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and brominated flame retardants (BFRs) were determined from blood samples, with total contamination ranging 7.6-47.7 ng/g ww for short-tailed shearwaters and 0.12-46.9 ng/g ww for little penguins. In both species contamination followed the same pattern where PCBs>OCPs>BFRs. BFR levels included the presence of the novel flame retardant hexabromobenzene (HBB). These novel results of POPs in seabirds in southeast Australia provide important information on the local (penguins) and global (shearwaters) distribution of POPs in the marine environment.
Chapter
As top predators, seabirds are highly sensitive to widespread plastic and metal pollution. These bioindicators interact with plastics and metals in many different ways which can lead to several deleterious effects, measurable through different techniques, and ultimately to death. Still, seabirds’ vulnerability to contamination depends on various characteristics such as foraging behaviour and habitat use. Seabirds can also constitute a significant biovector of plastic and metal contamination from marine environments to terrestrial landscapes. This chapter reviews the existing scientific knowledge regarding negative impacts of plastics and metals in marine ecosystems, particularly in seabirds, the way both are interconnected, and the reasons why seabirds are considered suitable biomonitoring tools of plastic and metal pollution patterns. Factors influencing both plastic and metal interactions with seabirds, as well as the currently known appropriate monitoring tools to quantify these interactions are also described. A review of studies addressing seabirds as vectors of plastic and metal pollution is also presented and a broad overview of these aspects is debated through a case study on how plastic exposure affects seabirds.
Article
Full-text available
Plastic pollution is a global environmental and human health issue, with plastics now ubiquitous in the environment and biota. Despite extensive international research, key knowledge gaps ("known unknowns") remain around ecosystem-scale and human health impacts of plastics in the environment, particularly in limnetic, coastal and marine systems. Here we review aquatic plastics research in three contrasting geographic and cultural settings, selected to present a gradient of heavily urbanised (and high population density) to less urbanised (and low population density) areas: China, the United Kingdom (UK), and Australia. Research from each country has varying environmental focus (for example, biota-focussed studies in Australia target various bird, fish, turtle and seal species, while UK and China-based studies focus on commercially important organisms such as bivalves, fish and decapods), and uses varying methods and reporting units (e.g. mean, median or range). This has resulted in aquatic plastics datasets that are hard to compare directly, supporting the need to converge on standardised sampling methods, and bioindicator species. While all the study nations show plastics contamination, often at high levels, datasets are variable and do not clearly demonstrate pollution gradients.
Article
Full-text available
Studies documenting plastic ingestion in animals have increased in recent years. Many do not describe the less conspicuous, sub-lethal impacts of plastic ingestion, such as reduced body condition or physiological changes. This means the severity of this global problem may have been underestimated. We conducted a critical review on the sub-lethal impacts of plastic ingestion on marine vertebrates (excluding fish). We found 34 papers which tried to measure plastics' impact using a variety of tools, and less than half of these detected any impact. The most common tools used were visual observations and body condition indices. Tools that explore animal physiology, such as histopathology, are a promising future approach to uncover the sub-lethal impacts of plastic ingestion in vertebrates. We encourage exploring impacts on species beyond the marine environment, using multiple tools or approaches, and continued research to discern the hidden impacts of plastic on global wildlife.
Article
Full-text available
This manual describes standard procedures for the collection and dissection of beachwashed Fulmars used in the Save the North Sea (SNS)'-Fulmar study. Save the North Sea is an international project which aims to reduce marine litter through increased awareness. Fulmars ingest marine litter and accumulate rubbish such as plastics in the stomachs. Therefore, Fulmars are used as the symbol of the SNS campaign. At the same time, litter in stomach contents of Fulmars is being developed as an international monitoring tool to measure changes in levels of litter. It is one of the Ecological Quality Objectives for the North Sea (EcoQOs') which OSPAR has to implement at the request of the Ministers of North Sea countries (NSC Bergen Declaration, March 2002). This report describes standard methods for handling bird corpses in the intended Fulmar-Litter-EcoQO.
Article
Chick growth of the short-tailed shearwater Puffinus tenuirostris, in a colony in Southern Tasmania was studied from mid January until the end of April 1988. Hatching took place between 10 and 25 January, with the peak occuring on 18 and 19 January. Fledging success was 35%. Mortality was concentrated in the middle of the nestling period and its main cause was predation by poachers and feral cats. Emergence from burrows began, on average, on the 88.7th night (±2.8SD) after hatching, which corresponded to 13.9 April (±2.5SD). After consecutive emergence for 8.8 days (±3.5SD), they fledged on the 97.1th day (±3.3SD) after hatching, with the peak occurring between April 23 and 29. Hatched chicks, on average, had: 10% the body weight, 40% the tarsus length and 50% the bill (exposed culmen) length of adults and attained adult sizes during the middle of the nestling period. Chicks attained the body weight of about 15% heavier than the average adult, however, they lost 25% of the peak body weight over the last three weeks and fledged at the mean body weight 13% lighter than the average adult. As compared with the early growth of their bony organs and body weight, their feather development was delayed. Tails began to sprout at 45.5 days (±2.6SD) after hatching and outer primaries sprouted at 34.2 days (±2.5SD) after hatching. These parts quickly developed in the second half of the nestling period. However, in 1988 the wings and tails of the chicks did not attain adult size and continued developing at the time of fledging. The long nestling period (97 days on average) and the rotation of growth and development of bony and feather parts might be effective for ensuring survival during the nestling period, by reducing the maximum energy demand for growth.
Article
The proportion of eggs that produced free-flying young increased with increasing breeding experience from an initial 0.4-0.45 to a maximum of 0.75-0.8, before falling to 0.55-0.65 in the most experienced birds. Overall, 10-11% of breeding shearwaters were absent, and 15-18% were present but not recorded with an egg, in any year. Both absentee and non-laying rates declined with increasing age. Older 1st-breeding birds had a higher initial reproductive success than those starting younger. Thereafter, there were no consistent differences in reproductive rates related to age of 1st breeding. Individuals that lived for longer had a higher reproductive success, on average, than shorter-lived birds, especially early in their reproductive careers. -from Authors
Article
Differences in rates of ingestion and types of plastic particles ingested by 218 sooty shearwaters, Puffinus griseus, and 324 short-tailed shearwaters, P. tenuirostris, obtained between 1970 and 1987 were examined. Of these seabirds, 193 sooty shearwaters (88.5%) and 265 short-tailed shearwaters (81.8%) were found to have ingested plastic particles. Significant differences in ingestion rates by year and area of collection were observed for short-tailed shearwaters. However, only one case of significant difference was observed for sooty shearwaters in the northern North Pacific. After analyzing plastic particles ingested by these two species of seabirds on the basis of shape and color, plastic molding materials ingested by short-tailed shearwaters were found to account for 67.2% of all particles. On the other hand, sooty shearwaters mainly ingested particles of plastic products, with plastic molding materials accounting for only 38.4%. These differences were believed to reflect the differences in food habits of the two species.