Organochlorine residues in harp seals, Phoca groenlandica, from the Gulf of St. Lawrence and Hudson Strait: an evaluation of contaminant concentrations and burdens

1994 ◽  
Vol 72 (1) ◽  
pp. 174-182 ◽  
Author(s):  
Gregor Gilpin Beck ◽  
Thomas G. Smith ◽  
Richard F. Addison

We evaluated organochlorine contaminant concentrations and burdens in blubber samples from 50 harp seals (Phoca groenlandica) obtained from the estuary and northern Gulf of St. Lawrence and Hudson Strait, Canada, between December 1988 and December 1989. The concentration and burden of PCBs increased significantly during the winter months for males occupying the St. Lawrence estuary. The potential for rapid accumulation of contaminants in the estuary was also observed among females: nine postpartum females (1 month after weaning) had higher organochlorine levels than prepartum females from the same location. The lowest observed contaminant concentrations and burdens were in seals from Hudson Strait in autumn. In winter specimens, males had DDT and PCB concentrations about 4 and 2 times as great, respectively, as females of similar age distribution and collection date. Congeners with IUPAC Nos. 138 and 153 accounted for more than 50% of total identifiable PCBs, which is consistent with their prevalence in other marine biota. The concentration of PCBs has declined and the percent p,p′-DDE of total DDT has increased between 1982 and the present study. Unlike the beluga whale (Delphinapterus leucas), harp seals occupy the more polluted waters of the estuary only seasonally, and this may account for their lower residue concentrations.

1999 ◽  
Vol 80 (2) ◽  
pp. S104-S112 ◽  
Author(s):  
Patrice Lapierre ◽  
Sylvain De Guise ◽  
Derek C.G. Muir ◽  
Ross Norstrom ◽  
Pierre Béland ◽  
...  

1990 ◽  
Vol 68 (6) ◽  
pp. 1327-1329 ◽  
Author(s):  
Pierre Béland ◽  
Annick Faucher ◽  
Patrice Corbeil

Several white adult beluga whales (Delphinapterus leucas) were observed to act together with a mother and calf. Underwater sound recordings, group behaviour, and calf appearance and behaviour strongly suggest that the birth had occurred during the observation period. Grey juveniles associated with the group remained at a distance during the whole event. The birth occurred in July during the presumed peak calving season, in a main channel of the St. Lawrence Estuary, home to an endangered population of belugas.


2020 ◽  
Vol 134 (1) ◽  
pp. 21-35
Author(s):  
Véronique Lesage ◽  
Stéphane Lair ◽  
Samuel Turgeon ◽  
Pierre Béland

Ecosystems and community structure fluctuate over time as a result of natural and anthropogenic factors that may affect prey availability and population dynamics. Most of what we know about St. Lawrence Estuary (SLE) Beluga (Delphinapterus leucas) diet comes from stomach contents collected 80 years ago mainly from a hunting site that Beluga no longer use. How reflective these data are of Beluga diet at other sites and at the current time is unknown. In the context of the recent population decline, general information of prey species alone may help identify useful conservation actions for potentially important prey or habitats. Here, we examined the diet of SLE Beluga using digestive tracts collected from carcasses recovered over the past 30 years, in the context of historical diet data and recent changes in the St. Lawrence ecosystem. We showed they have a varied diet composed of fish and invertebrates generally <30 cm in length, and that adult males and females differ in their summer diet in a way that is consistent with the sex segregation observed in this population. Our results also indicate that polychaete worms, squid, and cod are still among the most prevalent prey, and that species such as redfish (Sebastes spp.) might be important prey items. This study shows that Beluga diet has changed since the 1930s, and that prey from digestive tracts identified to species are valuable for making comparisons to the past, and for improving applications of molecular analyses, such as stable isotopes and fatty acids.


1994 ◽  
Vol 31 (4) ◽  
pp. 444-449 ◽  
Author(s):  
S. De Guise ◽  
A. Lagacé ◽  
P. Béland

A population of 450–500 belugas ( Delphinapterus leucas) resides in the polluted estuary of the St. Lawrence River. Stranded carcasses of this endangered population were recovered and necropsied. High concentrations of organochlorines, heavy metals, and benzo-a-pyrene exposure were demonstrated in tissues of these whales. Between 1988 and 1990, 21 tumors were found in 12 out of 24 carcasses. Among these tumors, six were malignant and 15 were benign. The animals were between 1.5 and >29 years of age, and the ages of animals with and without tumors did not differ when two juvenile animals (1.5 and 3.5 years of age) were excluded. Seven other neoplasms had been reported previously in six out of 21 well-preserved carcasses examined in the same laboratory between 1982 and 1987. Overall, 28 of the 75 confirmed tumors reported so far in cetaceans (37%) were from this small population of beluga whales in the St. Lawrence Estuary. Such a high prevalence of tumors would suggest an influence of contaminants through a direct carcinogenic effect and/or a decreased resistance to the development of tumors in this population.


1988 ◽  
Vol 98 (3) ◽  
pp. 287-310 ◽  
Author(s):  
D. Martineau ◽  
A. Lagacé ◽  
P. Béland ◽  
R. Higgins ◽  
D. Armstrong ◽  
...  

2002 ◽  
Vol 4 ◽  
pp. 259 ◽  
Author(s):  
Michael CS Kingsley ◽  
Isabelle Gauthier

The depleted population of belugas (Delphinapterus leucas) inhabiting the St Lawrence estuary, Canada, was monitored by periodic photographic aerial surveys. In order to correct counts made on aerial survey film and to obtain an estimate of the true size of the population, the diving behaviour and the visibility from the air of these animals was studied. A Secchi-disk turbidity survey in the belugas’ summer range showed that water clarity varied between 1.5 m and 11.6 m. By studying aerial photographs of sheet-plastic models of belugas that had been sunk to different depths below the surface, we found that models of white adults could be seen down to about the same depth as a Secchi disk, but no deeper. Smaller models of dark-grey juveniles could only be seen down to about 50% of Secchi-disk depth. By observing groups of belugas from a hovering helicopter and recording their disappearances and re-appearances, it was found that they were visible for 44.3% of the time, and that an appropriate correction for single photographs would be to multiply the photographic count by about 222% (SE 20%). For surveys in which there was overlap between adjacent frames, the estimated correction would be 209% (SE 16%). This correction factor was slightly conservative and gave an estimate of the true size of the population, based on a single survey, of 1,202 belugas (SE 189) in 1997. An estimate for 1997 based on smoothing 5 surveys 1988–1997 was 1,238 (SE 119).


Author(s):  
Richard St-Louis ◽  
Stephen de Mora ◽  
�milien Pelletier ◽  
Bill Doidge ◽  
Daniel Leclair ◽  
...  

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