Capelin (Mallotus villosus) and herring (Clupea harengus) as paratenic hosts of Anisakis simplex, a parasite of beluga (Delphinapterus leucas) in the St. Lawrence estuary

Capelin (Mallotus villosus) (N = 760) and herring (Clupea harengus) (N = 165) were collected in the St. Lawrence estuary during the summer of 1994 and 1995 to examine the importance of pelagic fish in transmission of Anisakis simplex to cetaceans. Larval A. simplex were removed from fish by means of a pepsin-digest solution or by dissection. Prevalence of A. simplex in dissected capelin was 5%, with a mean intensity of 1.2. Prevalences of A. simplex in herring were 95 and 99%, with mean intensities of 6.2 and 6.8 for pepsin digestion and dissection, respectively. Third-stage larval A. simplex found in capelin and herring were compared with third-stage larvae found in euphausiids and belugas (Delphinapterus leucas) from the St. Lawrence estuary and no differences in size or morphology of larvae from these four hosts were observed. Euphausiids, which harboured moulting second-stage and third-stage larvae, are intermediate hosts of A. simplex. As there was no apparent development of larvae in herring or capelin, these fish are considered to be paratenic hosts of A. simplex in the St. Lawrence estuary.

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Helminths of an endangered population of belugas, Delphinapterus leucas, in the St. Lawrence estuary, Canada

Canadian Journal of Zoology ◽

10.1139/z95-165 ◽

1995 ◽

Vol 73 (8) ◽

pp. 1402-1409 ◽

Cited By ~ 15

Author(s):

L. N. Measures ◽

P. Béland ◽

D. Martineau ◽

S. De Guise

Keyword(s):

Host Record ◽

Anisakis Simplex ◽

Morbidity And Mortality ◽

The Arctic ◽

Delphinapterus Leucas ◽

New Host ◽

Lawrence Estuary ◽

New Host Record ◽

Endangered Population ◽

St Lawrence Estuary

Helminths were identified in 38 belugas, Delphinapterus leucas, stranded in the St. Lawrence estuary and Gulf of St. Lawrence during 1984–1993. These helminth species were Anisakis simplex, Contracaecinea sp., Pseudoterranova sp., Stenurus arctomarinus, Pharurus pallasii, Halocercus taurica (new host record), Halocercus monoceris (new host record), Hadwenius seymouri, Diphyllobothrium sp., and Bolbosoma sp. (new host record). Of 21 helminths previously reported from populations of belugas worldwide, 7 were found in the St. Lawrence population. Lungworms, such as Halocercus monoceris, may prove useful in identification of beluga populations in the Arctic and may also be an important cause of morbidity and mortality of calves.

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Polychlorinated biphenyls and organochlorine compounds in brain, liver and muscle of beluga whales (Delphinapterus leucas) from the Arctic and St. Lawrence estuary

Marine Environmental Research ◽

10.1016/s0141-1136(98)00107-x ◽

1999 ◽

Vol 47 (1) ◽

pp. 1-15 ◽

Cited By ~ 29

Author(s):

C Metcalfe ◽

T Metcalfe ◽

S Ray ◽

G Paterson ◽

B Koenig

Keyword(s):

Polychlorinated Biphenyls ◽

Organochlorine Compounds ◽

The Arctic ◽

Delphinapterus Leucas ◽

Lawrence Estuary ◽

Beluga Whales ◽

St Lawrence Estuary

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

The Canadian Field-Naturalist ◽

10.22621/cfn.v134i1.2421 ◽

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.

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Régime alimentaire et principaux facteurs influençant l'alimentation des larves de capelan (Mallotus villosus), d'éperlan (Osmerus mordax) et de hareng (Clupea harengus harengus) dans un estuaire partiellement mélangé

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f86-119 ◽

1986 ◽

Vol 43 (5) ◽

pp. 968-979 ◽

Cited By ~ 13

Author(s):

R. Courtois ◽

J. J. Dodson

Keyword(s):

Feeding Rate ◽

Water Masses ◽

Clupea Harengus ◽

Gut Contents ◽

Osmerus Mordax ◽

Lawrence Estuary ◽

Daily Cycles ◽

Food And Feeding ◽

Clupea Harengus Harengus ◽

St Lawrence Estuary

The food and feeding rate periodicity of larvae of capelin (Mallotus villiosus), smelt (Osmerus mordax), and herring (Clupea harengus harengus) were studied to determine the existence of potential interactions between the larvae of these three species. Analyses of the gut contents showed that larvae of capelin started to feed before yolk sac absorption but that the feeding rate was low (<20%) in the lower St. Lawrence estuary; the small size of capelin larvae restricted their feeding to tintinnids. Larvae of the two other species feed at a greater rate than capelin larvae and their food is more diverse. The temporal sequence of feeding incidences showed daily cycles for the three species and semidiurnal cycles for larvae of capelin and herring. The importance of light for feeding of larvae was confirmed by the daily cycles and by the greater abundance of larvae with gut contents in surface waters (0–20 m). From the absence of a relation between biotic factors (density of larvae) and the temporal evolution of feeding incidences, we suggest that semidiurnal cycles are mainly related to temperature changes associated with advection of water masses at the sampling stations. Even though similar reactions to certain environmental variables were observed, we concluded that interspecific competition is minimal between larvae of the three species. Although present at the same stations, larvae of different species mainly occurred in distinct water masses; they are also mainly of different size. Those characteristics force them to exploit organisms of different size and mainly of different species.

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Euphausiids as intermediate hosts of Anisakis simplex in the St. Lawrence estuary

Canadian Journal of Zoology ◽

10.1139/z98-052 ◽

1998 ◽

Vol 76 (7) ◽

pp. 1226-1235 ◽

Cited By ~ 19

Author(s):

Réjean Hays ◽

Lena N Measures ◽

Jean Huot

Keyword(s):

Anisakis Simplex ◽

Intermediate Hosts ◽

Lawrence Estuary ◽

Second Stage ◽

The Third ◽

Third Stage ◽

Important Intermediate ◽

Meganyctiphanes Norvegica ◽

Saguenay River ◽

St Lawrence Estuary

To determine abundance of larval Anisakis simplex in euphausiids of the St. Lawrence estuary, Meganyctiphanes norvegica and Thysanoessa raschii were collected at seven sites from the mouth of the Saguenay River to Baie des Outardes. Larvae were removed from euphausiids by means of a modified Baermann apparatus filled with a pepsin-HCl digest solution. Abundances of larvae in euphausiids ranged from 0 to 58.2 × 10-5. Larvae (N = 100) were in the third stage (bearing one cuticle) or moulting from the second stage to the third stage (bearing two cuticles). Euphausiids, particularly T. raschii, which represented 98% of the total euphausiids sampled, are important intermediate hosts of A. simplex in the St. Lawrence estuary. These data indicate the importance of the St. Lawrence estuary as an enzootic zone for A. simplex and thus a valuable area to study the biology and the transmission of this parasite.

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

Environmental Research ◽

10.1006/enrs.1998.3942 ◽

1999 ◽

Vol 80 (2) ◽

pp. S104-S112 ◽

Cited By ~ 11

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

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Tumors in St. Lawrence Beluga Whales (Delphinapterus leucas)

Veterinary Pathology ◽

10.1177/030098589403100406 ◽

1994 ◽

Vol 31 (4) ◽

pp. 444-449 ◽

Cited By ~ 75

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.

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