Toxoplasma gondii infection in stranded St. Lawrence Estuary beluga Delphinapterus leucas in Quebec, Canada

2018 ◽  
Vol 130 (3) ◽  
pp. 165-175 ◽  
Author(s):  
A Iqbal ◽  
L Measures ◽  
S Lair ◽  
B Dixon
Keyword(s):  
Toxoplasma Gondii ◽  
Delphinapterus Leucas ◽  
Lawrence Estuary ◽  
Toxoplasma Gondii Infection ◽  
St Lawrence Estuary

scholarly journals Diet of St. Lawrence Estuary Beluga (Delphinapterus leucas) in a changing ecosystem

2020 ◽  
Vol 134 (1) ◽  
pp. 21-35
Author(s):  
Véronique Lesage ◽  
Stéphane Lair ◽  
Samuel Turgeon ◽  
Pierre Béland
Keyword(s):  
Prey Availability ◽  
Population Decline ◽  
Delphinapterus Leucas ◽  
Anthropogenic Factors ◽  
Adult Males ◽  
Current Time ◽  
Lawrence Estuary ◽  
The Past ◽  
Important Prey ◽  
St Lawrence Estuary

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.

Immune Functions in the Fisher Rat Fed Beluga Whale (Delphinapterus leucas) Blubber from the Contaminated St. Lawrence Estuary

1999 ◽  
Vol 80 (2) ◽  
pp. S104-S112 ◽  
Author(s):  
Patrice Lapierre ◽  
Sylvain De Guise ◽  
Derek C.G. Muir ◽  
Ross Norstrom ◽  
Pierre Béland ◽  
...  
Keyword(s):  
Beluga Whale ◽  
Delphinapterus Leucas ◽  
Immune Functions ◽  
Lawrence Estuary ◽  
Beluga Whale Delphinapterus Leucas ◽  
St Lawrence Estuary

scholarly journals Tumors in St. Lawrence Beluga Whales (Delphinapterus leucas)

1994 ◽  
Vol 31 (4) ◽  
pp. 444-449 ◽  
Author(s):  
S. De Guise ◽  
A. Lagacé ◽  
P. Béland
Keyword(s):  
Small Population ◽  
Delphinapterus Leucas ◽  
Carcinogenic Effect ◽  
Lawrence Estuary ◽  
Beluga Whales ◽  
High Prevalence ◽  
Endangered Population ◽  
High Concentrations ◽  
St Lawrence Estuary ◽  
St Lawrence River

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.

Pathology of stranded beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, Québec, Canada

1988 ◽  
Vol 98 (3) ◽  
pp. 287-310 ◽  
Author(s):  
D. Martineau ◽  
A. Lagacé ◽  
P. Béland ◽  
R. Higgins ◽  
D. Armstrong ◽  
...  
Keyword(s):  
Delphinapterus Leucas ◽  
Lawrence Estuary ◽  
Beluga Whales ◽  
St Lawrence Estuary

scholarly journals Visibility of St Lawrence belugas to aerial photography, estimated by direct observation

2002 ◽  
Vol 4 ◽  
pp. 259 ◽  
Author(s):  
Michael CS Kingsley ◽  
Isabelle Gauthier
Keyword(s):  
Water Clarity ◽  
Population Based ◽  
Aerial Survey ◽  
Aerial Photographs ◽  
Delphinapterus Leucas ◽  
Secchi Disk ◽  
Lawrence Estuary ◽  
Summer Range ◽  
Different Depths ◽  
St Lawrence Estuary

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).

Hepatic butyltin concentrations in beluga whales?(Delphinapterus leucas) from the St Lawrence Estuary and northern Quebec, Canada

2000 ◽  
Vol 14 (4) ◽  
pp. 218-226 ◽  
Author(s):  
Richard St-Louis ◽  
Stephen de Mora ◽  
�milien Pelletier ◽  
Bill Doidge ◽  
Daniel Leclair ◽  
...  
Keyword(s):  
Delphinapterus Leucas ◽  
Lawrence Estuary ◽  
Beluga Whales ◽  
St Lawrence Estuary
Sign in / Sign up

Export Citation Format

Share Document