Spatial and Temporal Variations in Chemical Contamination of American Eels, Anguilla rostrata, Captured in the Estuary of the St, Lawrence River

1994 ◽  
Vol 51 (2) ◽  
pp. 464-478 ◽  
Author(s):  
P. V. Hodson ◽  
M. Castonguay ◽  
C. M. Couillard ◽  
C. Desjardins ◽  
E. Pelletier ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Delphinapterus Leucas ◽  
Anguilla Rostrata ◽  
Chemical Contamination ◽  
Reference Sites ◽  
Beluga Whales ◽  
Pcb Congeners ◽  
American Eels ◽  
St Lawrence River

Levels of polychlorinated biphenyls (PCBs), mirex, and pesticides were 10–100 times higher in migratory adult American eels, Anguilla rostrata, sampled at Kamouraska, Quebec, in 1990 than in eels from an uncontaminated reference tributary; concentrations in eels within the estuary varied little among sites. In contrast, mercury levels were the same at estuarine and reference sites, suggesting natural sources or atmospheric deposition of mercury. Dioxins, furans, and polynuclear aromatic hydrocarbons were virtually absent at all sites. During the 7 wk of migration, levels of PCBs, mirex, and pesticides in eels increased, while mercury did not. Since 1982, levels of PCBs and mirex have declined by 68 and 56%, respectively, and the percentage of eels exceeding human health guidelines for PCBs and mirex was about twofold lower in 1990 than in 1982. Levels of other pesticides have also declined, except that dieldrin is unchanged since 1982. While chemical concentrations are declining, levels of specific, highly toxic PCB congeners are sufficiently high that eel consumption by beluga whales (Delphinapterus leucas) is still likely to be hazardous. The hazard to the eels themselves is unknown due to a scarcity of toxicity data, but the highest concentrations of chemicals were observed in gonads.

Why Is Recruitment of the American Eel, Anguilla rostrata, Declining in the St. Lawrence River and Gulf?

1994 ◽  
Vol 51 (2) ◽  
pp. 479-488 ◽  
Author(s):  
M. Castonguay ◽  
P. V. Hodson ◽  
C. M. Couillard ◽  
M. J. Eckersley ◽  
J.-D. Dutil ◽  
...  
Keyword(s):  
Anguilla Rostrata ◽  
Commercial Fishing ◽  
Hydroelectric Dams ◽  
Chemical Contamination ◽  
The Past ◽  
Silver Eels ◽  
High Prevalence ◽  
American Eels ◽  
Reference Stock ◽  
St Lawrence River

We critically review four potential causes of a drastic decline in juvenile American eels, Anguilla rostrata, recruiting to Lake Ontario (81-fold decline from 1985 to 1992) and in juvenile eel densities in tributaries to the Gulf of St. Lawrence. Silver eels from the St. Lawrence River were much more contaminated and had a high prevalence of deformities and lesions than a reference stock although they were on average less contaminated in 1990 than in 1982 (1.12 versus 4.54 μgg−1 for PCB; 0.025 versus 0.07 μg∙g−1 for mirex). Lethal toxicity from chemical contamination has been known to occur in St. Lawrence River eels for the past 25–30 yr. Major habitat modifications in the St. Lawrence took place in the 1950's (St. Lawrence Seaway and hydroelectric dams), about 30 yr before recruitment started declining; this long delay argues against these perturbations being primary causes of the decline. There is little evidence that commercial fishing and oceanographic changes caused the decline. Overall, we conclude that we do not know what caused the pronounced recruitment decline. We propose research avenues and hypotheses that may advance understanding and emphasize that because of panmixia, the recruitment decline could be species wide.

Correlations between pathological changes and chemical contamination in American eels, Anguilla rostrata, from the St. Lawrence River

1997 ◽  
Vol 54 (8) ◽  
pp. 1916-1927 ◽  
Author(s):  
C M Couillard ◽  
P V Hodson ◽  
M Castonguay
Keyword(s):  
Anguilla Rostrata ◽  
Chemical Contamination ◽  
Pathological Changes ◽  
Preneoplastic Lesions ◽  
Biomarkers Of Exposure ◽  
Reproductive Impairment ◽  
Migratory Season ◽  
American Eels ◽  
The Relationship ◽  
St Lawrence River

American eel (Anguilla rostrata) from the St. Lawrence River are heavily contaminated with chemicals that may be associated with increased incidence of diseases and reproductive impairment. The relationship between tissue mirex concentration and body mass was used to separate eels into two groups: the proportion of eels migrating from contaminated areas (Lake Ontario and upper St. Lawrence River) increased as the migration season progressed. Vertebral malformations and basophilic foci in the liver (preneoplastic lesions) were more frequent at the end of the migratory season, when the eels were more heavily contaminated with organochlorine compounds. In contrast, mesenteric nematodes were more common in the first week of the season, when eels were less contaminated. Diameters and percentages of different stages of oocytes, and density and surface area of pigmented macrophage aggregates in the spleen, did not vary among weeks. While basophilic foci are specific biomarkers of exposure to environmental contaminants, vertebral malformations may be caused by a variety of other anthropogenic or natural factors.\b Further studies are needed to confirm the observed associations between chemical contamination and pathological changes.

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.

The migration of stocked, trapped and transported, and wild female American silver eels through the Gulf of St. Lawrence

2018 ◽  
Vol 75 (11) ◽  
pp. 2024-2037 ◽  
Author(s):  
Mélanie Béguer-Pon ◽  
Guy Verreault ◽  
David Stanley ◽  
Martin Castonguay ◽  
Julian J. Dodson
Keyword(s):  
Detection Efficiency ◽  
Anguilla Rostrata ◽  
Migration Speed ◽  
Hydroelectric Dams ◽  
Wild Female ◽  
Swimming Depth ◽  
Silver Eels ◽  
Diel Vertical Migrations ◽  
American Eels ◽  
St Lawrence River

The stocking of juvenile eels and trap and transport programs of large yellow (American) eels (Anguilla rostrata) were initiated in Ontario to mitigate mortalities observed at hydroelectric dams and to increase escapement from the upper St. Lawrence River and Lake Ontario (Canada). A total of 380 migrating female silver eels (stocked, trapped and transported, and wild) were tagged with acoustic transmitters between 2011 and 2014. Their migration and escapement at the exit of the Gulf of St. Lawrence, the Cabot Strait, were recorded using acoustic receivers. Escapement rates varied between 8.9% and 20.0% annually (mean = 11.4%). A high proportion of stocked eels were detected (N = 27 of 43 detected at Cabot Strait), demonstrating their ability to escape the Gulf. No differences in migration speed or crossing locations at Cabot Strait were found among the three categories. Eels crossing Cabot Strait did not display diel and tidal patterns, but their estimated swimming depth indicated diel vertical migrations. The low escapement rates observed may be related to predation events and (or) the low and variable detection efficiency of the acoustic receivers’ line.

PCBs and organochlorine pesticides in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), 1994–1998

2003 ◽  
Vol 122 (2) ◽  
pp. 291-302 ◽  
Author(s):  
Karen E Hobbs ◽  
Derek C.G Muir ◽  
Robert Michaud ◽  
Pierre Béland ◽  
Robert J Letcher ◽  
...  
Keyword(s):  
Organochlorine Pesticides ◽  
River Estuary ◽  
Delphinapterus Leucas ◽  
Beluga Whales ◽  
Free Ranging ◽  
St Lawrence River

Occurrence of Chlorinated Paraffins in Beluga Whales (Delphinapterus leucas) from the St. Lawrence River and Rainbow Trout (Oncorhynchus mykiss) and Carp (Cyprinus carpio) from Lake Ontario

2000 ◽  
Vol 35 (2) ◽  
pp. 263-282 ◽  
Author(s):  
D.T. Bennie ◽  
C.A. Sullivan ◽  
R.J. Maguire
Keyword(s):  
Rainbow Trout ◽  
Lake Ontario ◽  
Delphinapterus Leucas ◽  
Freshwater Species ◽  
Beluga Whales ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Chlorinated Paraffins ◽  
Carp Cyprinus Carpio ◽  
Wet Weight ◽  
St Lawrence River

Abstract Samples of 25 dead beluga whales (Delphinapterus leucas) from the St. Lawrence River estuary, as well as samples of 10 rainbow trout (Oncorhynchus mykiss) and 3 carp (Cyprinus carpio) caught in western Lake Ontario were analyzed for total short- (C10-C13) and medium-(C14-C17) chain chlorinated paraffins (SMCCPs) using gas chromatography-low resolution negative chemical ioniza-tion mass spectrometry (GC-NCI-MS) in the selected ion monitoring mode (SIM). Short- and medium-chain chlorinated paraffins were quantitatively identified using two commercial preparations. SMCCPs were detected in all samples. Results ranged from 1.1 to 59 µg/g wet weight in beluga liver tissue, from 6.4 to 166 µg/g wet weight in beluga blubber, and from 0.41 to 9.7 µg/g wet weight in the two freshwater species. The beluga results are higher than those reported for marine mammals in Europe. Total short- and medium-chain chlorinated paraffin levels in the beluga blubber are comparable to previous ∑PCB and ∑DDT results for the same population of beluga whales. The mean ∑SMC-CP concentration in the carp was 0.90 µg/g wet weight and 2.7 µg/g wet weight in the rainbow trout. Results from the freshwater species are comparable to those reported for fish sampled from other industrially impacted waterways in North America but are elevated relative to marine species from European studies. Comparison of the SIM GC-NCI-MS data with results of gas chromatogra-phy-high resolution negative ion mass spectrometry (GC-HR-NIMS) analysis from another study showed that the two analytical techniques are not congruent. The differences may be due to the effects of coeluting interfering organochlorine substances.

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