ROBIN W. BAIRD* and SASCHA K. HOOKER 1
Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1
Considerable quantities of plastic debris are found throughout the worldÕs oceans (e.g., Dufault and
Whitehead, 1994), and may impact a diversity of species, including marine turtles, birds and mammals (Laist, 1997). Since many species of whales and dolphins live in waters far from shore, and may sink upon death, opportunities to record instances of ingestion of marine debris by cetaceans are infrequent. Despite this, there are several cases where ingestion of plastic or other
marine debris has been documented for cetaceans, with published reports existing for 21 species of odontocetes (Laist, 1997). We know of an additional ®ve species of
odontocetes for which marine debris ingestion has been documented: the killer whale (Orcinus orca; K. Evans, pers. comm.), northern bottlenose whale (Hyperoodon ampullatus; R. Michaud, pers. comm.), ®nless porpoise (Neophocoena phocoenoides; C. Parsons, pers. comm.),
white-beaked dolphin (Lagenorhynchus albirostris; R. Kastelein, pers. comm.), and pantropical spotted dolphin (Stenella attenuata; K. Robertson, pers. comm.). For most species of odontocetes, only one or a few records have been reported. Here we document the
third reported case of plastic ingestion by a harbour porpoise (Phocoena phocoena), and discuss factors that might have contributed to its ingestion.
On 11 September 1997, a harbour porpoise was found dead on a beach near Pictou, Nova Scotia, Canada (45° 410N, 62° 420W), bordering Northumberland Strait in the Gulf of Saint Lawrence. The animal was buried on the beach where it was found, and then uncovered on 14 September and transported to Halifax, Nova Scotia, where it was frozen intact for later post-mortem. While
the animal had been dead for at least four days prior to freezing, because it had been buried, relatively little external damage from gulls or other scavengers was apparent. Upon external examination, it was noted that the porpoise, a 95.2 cm long male, was visibly emaciated, with a distinct concavity of the dorsal surface on both sides of the body, indicating atrophy of the epaxial muscles. The leading edge of the ¯ippers, ¯ukes, and dorsal ®n, as well as the area around the snout, were all examined for net marking, but showed no signs of incidental entanglement in ®shing gear. All thoracic and abdominal organ systems were examined, and no obvious gross pathology was noted. The stomach and intestines were empty, other than small amounts of bile stained liquid throughout the intestine. Upon examination of the esophagus, a balled up piece of black plastic (measuring when stretched out about 5 by 7 cm, weighing 0.36 g) was found adjacent to the junction with the stomach. Immediately cranial to this plastic was a
mass of ®sh bones, partially digested ®sh, and three intact ®sh (a total of 2.7 g), all occluding the esophagus.
The lining of esophagus immediately adjacent to the mass of ®sh peeled o€ easily, while the lining further cranial, as well as the stomach lining, remained ®rmly attached. However, histological examination of the esophageal lining showed no obvious necrosis (P.-Y. Daoust, pers. comm.). The ®sh remains recovered were identi®ed as three-spined stickleback, Gasterosteus
aculeatus (W.A. Walker, pers. comm.). A total of 18 individuals were represented, ranging in size from 22 to 28 mm standard length, and all had been recently ingested.
This appears to be the ®rst record of three-spined stickleback recovered from a harbour porpoise (see for example Fontaine et al., 1994; Gannon et al., 1998; Rae, 1965, 1973; Recchia and Read, 1989; Smith and Gaskin, 1974; Smith and Read, 1992), and possibly the ®rst re-
cord of predation on this ®sh by any species of cetacean, though they are regularly consumed by otters, Lutra lutra (Breathnach and Fairley, 1993). As noted, there are two previous records of plastic ingestion for this species (Kastelein and Lavaleije, 1992; Walker and Coe, 1990),
and several additional unpublished records of plastic ingestion exist from The Netherlands (R. Kastelein, pers. comm.). In our case, the ingested plastic probably blocked the esophagus, although for how long is not Marine Pollution Bulletin Vol. 40, No. 8, pp. 719±720, 2000
Ó 2000 Elsevier Science Ltd. All rights reserved Printed in Great Britain PII: S0025-326X(00)00051-5 0025-326X/00 $ - see front matter *Corresponding author.
E-mail address: rwbaird@is.dal.ca (R.W. Baird). 1 Present address: British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 DET ,UK. 719 clear, though it is unlikely to have been for very long, given there was no necrosis associated with the blockage.
We do not know whether this plastic caused the death of the individual, but its emaciated state and the presence of a previously undocumented prey species suggests that the individual may have been investigating inappropriate prey items. Based on its size and timing of the stranding,
it is likely that this individual was only a few months of age, and likely had not yet been weaned (J. Barnett, pers. comm.), thus pre-weaning separation from its mother
may have led to the ingestion of inappropriate items. We would like to thank Melanie Lowe, who found and reported the porpoise, and Maureen OÕHalloran and Jeannie Staples, who trans-
ported it to Halifax. The necropsy was assisted in by Jenny Christal, Shannon Gowans, Luke Rendell, Peter Simard, and histological examination of tissues was undertaken by Pierre-Yves Daoust, Atlantic Veterinary College, PEI. Others provided references or unpublished data on plastic ingestion, including Karen Evans, Ron Kastelein, David Laist, Mardik Leopold, Robert Michaud, Chris Parsons, and Kelly Robertson. Constructive comments on the manuscript were
made by Pierre-Yves Daoust, Ron Kastelein, Bill Walker and an anonymous reviewer.
Breathnach, S. and Fairley, J. S. (1993) The diet of otters Lutra lutra (L.) in the Clare River system. Proceedings of the Royal Irish Academy 93B, 151±158. Dufault, S. and Whitehead, H. (1994) Floating marine pollution in Ôthe GullyÕ on the continental slope, Nova Scotia, Canada. Marine Pollution Bulletin 28, 489±493.
Fontaine, P. M., Hammill, M. O., Barrette, C. and Kingsley, M. C. (1994) Summer diet of the harbor porpoise (Phocoena phocoena) in the estuary and northern Gulf of St. Lawrence. Canadian Journal of Fisheries and Aquatic Sciences 51, 172±178. Gannon, D. P., Craddock, J. E. and Read, A. J. (1998) Autumn food habits of harbor porpoises, Phocoena phocoena, in the Gulf of Maine. Fishery Bulletin of the United States 96, 428±437. Kastelein, R. A. and Lavaleije, M. S. S. (1992) Foreign bodies in the stomach of a female harbour porpoise (Phocoena phocoena) from
the North Sea. Aquatic Mammals 18, 40±46. Laist, D. W. (1997) Impacts of marine debris: entanglement of marine life in marine debris including a comprehensive list of species with
entanglement and ingestion records. In Marine Debris: Sources, Impacts, and Solutions, eds. J. M. Coe and D. B. Rogers, pp. 99± 139. Springer, New York. Rae, B. B. (1965) The food of the common porpoise (Phocaena phocaena). Journal of Zoology London 146, 114±122. Rae, B. B. (1973) Additional notes on the food of the common porpoise (Phocoena phocoena). Journal of Zoology London 169, 127± 131. Recchia, C. A. and Read, A. J. (1989) Stomach contents of harbour porpoises, Phocoena phocoena (L.), from the Bay of Fundy. Canadian Journal of Zoology 67, 2140±2146. Smith, G. J. D. and Gaskin, D. E. (1974). The diet of harbor porpoises
(Phocoena phocoena (L.)) in coastal waters of eastern Canada, with special reference to the Bay of Fundy. Canadian Journal of Zoology 52, 777±782. Smith, R. J. and Read, A. J. (1992). Consumption of euphausiids by harbour porpoise (Phocoena phocoena) calves in the Bay of Fundy. Canadian Journal of Zoology 70, 1629±1632. Walker, W. A. and Coe, J. M. (1990). Survey of marine debris ingestion by odontocete cetaceans. NOAA Technical Memorandum NMFS-SWFSC 154, 747±774. 720 Marine Pollution Bulletin
Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1
Considerable quantities of plastic debris are found throughout the worldÕs oceans (e.g., Dufault and
Whitehead, 1994), and may impact a diversity of species, including marine turtles, birds and mammals (Laist, 1997). Since many species of whales and dolphins live in waters far from shore, and may sink upon death, opportunities to record instances of ingestion of marine debris by cetaceans are infrequent. Despite this, there are several cases where ingestion of plastic or other
marine debris has been documented for cetaceans, with published reports existing for 21 species of odontocetes (Laist, 1997). We know of an additional ®ve species of
odontocetes for which marine debris ingestion has been documented: the killer whale (Orcinus orca; K. Evans, pers. comm.), northern bottlenose whale (Hyperoodon ampullatus; R. Michaud, pers. comm.), ®nless porpoise (Neophocoena phocoenoides; C. Parsons, pers. comm.),
white-beaked dolphin (Lagenorhynchus albirostris; R. Kastelein, pers. comm.), and pantropical spotted dolphin (Stenella attenuata; K. Robertson, pers. comm.). For most species of odontocetes, only one or a few records have been reported. Here we document the
third reported case of plastic ingestion by a harbour porpoise (Phocoena phocoena), and discuss factors that might have contributed to its ingestion.
On 11 September 1997, a harbour porpoise was found dead on a beach near Pictou, Nova Scotia, Canada (45° 410N, 62° 420W), bordering Northumberland Strait in the Gulf of Saint Lawrence. The animal was buried on the beach where it was found, and then uncovered on 14 September and transported to Halifax, Nova Scotia, where it was frozen intact for later post-mortem. While
the animal had been dead for at least four days prior to freezing, because it had been buried, relatively little external damage from gulls or other scavengers was apparent. Upon external examination, it was noted that the porpoise, a 95.2 cm long male, was visibly emaciated, with a distinct concavity of the dorsal surface on both sides of the body, indicating atrophy of the epaxial muscles. The leading edge of the ¯ippers, ¯ukes, and dorsal ®n, as well as the area around the snout, were all examined for net marking, but showed no signs of incidental entanglement in ®shing gear. All thoracic and abdominal organ systems were examined, and no obvious gross pathology was noted. The stomach and intestines were empty, other than small amounts of bile stained liquid throughout the intestine. Upon examination of the esophagus, a balled up piece of black plastic (measuring when stretched out about 5 by 7 cm, weighing 0.36 g) was found adjacent to the junction with the stomach. Immediately cranial to this plastic was a
mass of ®sh bones, partially digested ®sh, and three intact ®sh (a total of 2.7 g), all occluding the esophagus.
The lining of esophagus immediately adjacent to the mass of ®sh peeled o€ easily, while the lining further cranial, as well as the stomach lining, remained ®rmly attached. However, histological examination of the esophageal lining showed no obvious necrosis (P.-Y. Daoust, pers. comm.). The ®sh remains recovered were identi®ed as three-spined stickleback, Gasterosteus
aculeatus (W.A. Walker, pers. comm.). A total of 18 individuals were represented, ranging in size from 22 to 28 mm standard length, and all had been recently ingested.
This appears to be the ®rst record of three-spined stickleback recovered from a harbour porpoise (see for example Fontaine et al., 1994; Gannon et al., 1998; Rae, 1965, 1973; Recchia and Read, 1989; Smith and Gaskin, 1974; Smith and Read, 1992), and possibly the ®rst re-
cord of predation on this ®sh by any species of cetacean, though they are regularly consumed by otters, Lutra lutra (Breathnach and Fairley, 1993). As noted, there are two previous records of plastic ingestion for this species (Kastelein and Lavaleije, 1992; Walker and Coe, 1990),
and several additional unpublished records of plastic ingestion exist from The Netherlands (R. Kastelein, pers. comm.). In our case, the ingested plastic probably blocked the esophagus, although for how long is not Marine Pollution Bulletin Vol. 40, No. 8, pp. 719±720, 2000
Ó 2000 Elsevier Science Ltd. All rights reserved Printed in Great Britain PII: S0025-326X(00)00051-5 0025-326X/00 $ - see front matter *Corresponding author.
E-mail address: rwbaird@is.dal.ca (R.W. Baird). 1 Present address: British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 DET ,UK. 719 clear, though it is unlikely to have been for very long, given there was no necrosis associated with the blockage.
We do not know whether this plastic caused the death of the individual, but its emaciated state and the presence of a previously undocumented prey species suggests that the individual may have been investigating inappropriate prey items. Based on its size and timing of the stranding,
it is likely that this individual was only a few months of age, and likely had not yet been weaned (J. Barnett, pers. comm.), thus pre-weaning separation from its mother
may have led to the ingestion of inappropriate items. We would like to thank Melanie Lowe, who found and reported the porpoise, and Maureen OÕHalloran and Jeannie Staples, who trans-
ported it to Halifax. The necropsy was assisted in by Jenny Christal, Shannon Gowans, Luke Rendell, Peter Simard, and histological examination of tissues was undertaken by Pierre-Yves Daoust, Atlantic Veterinary College, PEI. Others provided references or unpublished data on plastic ingestion, including Karen Evans, Ron Kastelein, David Laist, Mardik Leopold, Robert Michaud, Chris Parsons, and Kelly Robertson. Constructive comments on the manuscript were
made by Pierre-Yves Daoust, Ron Kastelein, Bill Walker and an anonymous reviewer.
Breathnach, S. and Fairley, J. S. (1993) The diet of otters Lutra lutra (L.) in the Clare River system. Proceedings of the Royal Irish Academy 93B, 151±158. Dufault, S. and Whitehead, H. (1994) Floating marine pollution in Ôthe GullyÕ on the continental slope, Nova Scotia, Canada. Marine Pollution Bulletin 28, 489±493.
Fontaine, P. M., Hammill, M. O., Barrette, C. and Kingsley, M. C. (1994) Summer diet of the harbor porpoise (Phocoena phocoena) in the estuary and northern Gulf of St. Lawrence. Canadian Journal of Fisheries and Aquatic Sciences 51, 172±178. Gannon, D. P., Craddock, J. E. and Read, A. J. (1998) Autumn food habits of harbor porpoises, Phocoena phocoena, in the Gulf of Maine. Fishery Bulletin of the United States 96, 428±437. Kastelein, R. A. and Lavaleije, M. S. S. (1992) Foreign bodies in the stomach of a female harbour porpoise (Phocoena phocoena) from
the North Sea. Aquatic Mammals 18, 40±46. Laist, D. W. (1997) Impacts of marine debris: entanglement of marine life in marine debris including a comprehensive list of species with
entanglement and ingestion records. In Marine Debris: Sources, Impacts, and Solutions, eds. J. M. Coe and D. B. Rogers, pp. 99± 139. Springer, New York. Rae, B. B. (1965) The food of the common porpoise (Phocaena phocaena). Journal of Zoology London 146, 114±122. Rae, B. B. (1973) Additional notes on the food of the common porpoise (Phocoena phocoena). Journal of Zoology London 169, 127± 131. Recchia, C. A. and Read, A. J. (1989) Stomach contents of harbour porpoises, Phocoena phocoena (L.), from the Bay of Fundy. Canadian Journal of Zoology 67, 2140±2146. Smith, G. J. D. and Gaskin, D. E. (1974). The diet of harbor porpoises
(Phocoena phocoena (L.)) in coastal waters of eastern Canada, with special reference to the Bay of Fundy. Canadian Journal of Zoology 52, 777±782. Smith, R. J. and Read, A. J. (1992). Consumption of euphausiids by harbour porpoise (Phocoena phocoena) calves in the Bay of Fundy. Canadian Journal of Zoology 70, 1629±1632. Walker, W. A. and Coe, J. M. (1990). Survey of marine debris ingestion by odontocete cetaceans. NOAA Technical Memorandum NMFS-SWFSC 154, 747±774. 720 Marine Pollution Bulletin
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