Concentration of capelin (Mallotus villosus) in tidal upwelling fronts at the head of the Laurentian Channel in the St. Lawrence estuary

1999 ◽  
Vol 56 (10) ◽  
pp. 1832-1848 ◽  
Author(s):  
Caroline Marchand ◽  
Yvan Simard ◽  
Yves Gratton
Keyword(s):  
Tidal Cycle ◽  
High Tide ◽  
Stomach Contents ◽  
Mallotus Villosus ◽  
Lawrence Estuary ◽  
Threshold Response ◽  
Capelin Mallotus Villosus ◽  
Gut Fullness ◽  
St Lawrence Estuary ◽  
Upwelling Area

In 1994 and 1995, continuous monitoring of physical characteristics and echo integration were used to detect aggregations of capelin (Mallotus villosus) in the upper water column in relation to thermal fronts and to examine the tidal dynamics in an intense upwelling area at the head of the Laurentian Channel. During the four cruises, fish aggregations were recorded for 72% of the fronts (n = 61) resulting from the periodic upwelling of cold waters. Over the tidal cycle, only a low fish biomass was detected when the cold intermediate waters (<2°C) upwelled during high tide; 90% of the 2-year-old capelin biomass was detected in water temperatures >2°C. Capelin zooplankton prey were concentrated primarily over the deep Laurentian Channel, with very small numbers being found in the shallower areas nearby, where the fronts occurred. The prey concentrations did not increase at the fronts at any phase of the tidal cycle. The few zooplankton patches detected by the optical plankton counter did not correspond to either physical structures or fish concentrations. The gut fullness index and the stomach contents of the capelin caught in fronts did not differ from those of capelin caught elsewhere. These frontal aggregations of capelin seem therefore to be driven more by a threshold response to low temperatures than by trophic interactions based on a higher prey density.

Utility of Meristic and Morphometric Characters for Identification of Capelin (Mallotus villosus) Stocks in Canadian Atlantic Waters

1978 ◽  
Vol 35 (1) ◽  
pp. 124-130 ◽  
Author(s):  
Joan C. Sharp ◽  
Kenneth W. Able ◽  
William C. Leggett ◽  
James E. Carscadden
Keyword(s):  
Mallotus Villosus ◽  
Meristic Characters ◽  
Body Depth ◽  
Morphometric Characters ◽  
Lawrence Estuary ◽  
Grand Banks ◽  
Capelin Mallotus Villosus ◽  
Statistical Separation ◽  
And Migration ◽  
St Lawrence Estuary

Multivariate discriminant function analyses were performed on 9 morphometric and 11 meristic characters of capelin (Mallotus villosus) samples at Île aux Coudres in the St. Lawrence estuary; Sept Îles, Natashquan, and Grande Rivière in the Gulf of St. Lawrence; Southeast Shoal on the Grand Banks; and Herring Neck, Notre Dame Bay, Newfoundland. Analyses of meristic characters provided no evidence of discrete stocks. Analyses of morphometric characters provided strong statistical separation between areas. A posteriori classification of groups yielded 93.1% correct classification for males and 73.3% for females. Only snout length, eye diameter, head length, and body depth contributed significantly to the separation obtained. These findings suggest that meristic characters offer little potential for stock identification in Canadian Atlantic waters. Morphometric characters may prove useful, but further study, corroborated with life history and migration data, is required to confirm this. Key words: capelin, Mallotus villosus, meristics, morphometrics, stock separation, Gulf of St. Lawrence, Newfoundland, Canadian Atlantic, multivariate analysis

Seasonal Distribution, Abundance, and Growth of Larval Capelin (Mallotus villosus) in the St. Lawrence Estuary and Northwestern Gulf of St. Lawrence

1977 ◽  
Vol 34 (11) ◽  
pp. 2008-2014 ◽  
Author(s):  
Bernadette Jacquaz ◽  
Kenneth W. Able ◽  
William C. Leggett
Keyword(s):  
Primary Production ◽  
Larval Transport ◽  
Larval Abundance ◽  
Mallotus Villosus ◽  
Daily Growth ◽  
Lawrence Estuary ◽  
Capelin Mallotus Villosus ◽  
Feeding Area ◽  
Anticosti Island ◽  
St Lawrence Estuary

Capelin (Mallotus villosus) larvae in the St. Lawrence estuary and northwestern Gulf of St. Lawrence were most abundant in 1974 and 1975 in the upper estuary in early June; this coincided with the spring peak in primary production. A spectacular decline (>99%) in larval abundance between June and September resulted principally from their downstream transport by currents. In October and November larval capelin were concentrated in a large counterclockwise gyre located in the northwestern Gulf between Anticosti Island and Pointe des Monts. This region is within the area of maximum primary production in the estuary and Gulf and may serve as an important feeding area for larval capelin. Length of capelin larvae at the end of the first growing season in the estuary and northwestern Gulf was greater than that of capelin from Newfoundland, Labrador, and Greenland. However, this difference may have resulted from sampling biases. Daily growth rates of capelin larvae from these areas were similar. Key words: capelin, Mallotus villosus, St. Lawrence, seasonal distributions, larval transport, growth, vertical distribution

Patterns of Larval Emergence and Their Potential Impact on Stock Differentiation in Beach Spawning Capelin (Mallotus villosus)

1987 ◽  
Vol 44 (7) ◽  
pp. 1326-1336 ◽  
Author(s):  
Louis Fortier ◽  
William C. Leggett ◽  
Serge Gosselin
Keyword(s):  
Dark Phase ◽  
Mallotus Villosus ◽  
Lawrence Estuary ◽  
Larval Stages ◽  
Abrupt Changes ◽  
Capelin Mallotus Villosus ◽  
Larval Emergence ◽  
Laboratory Emergence ◽  
St Lawrence Estuary ◽  
Stock Differentiation

The environmental cues triggering larval capelin (Mallotus villosus) emergence in the St. Lawrence estuary and in coastal Newfoundland are different. In the estuary, emergence from the intertidal and subtidal spawning grounds starts with dusk and ends with dawn, indicating an active response to low light intensity. In the laboratory, emergence from undisturbed sediments collected in the field is perfectly synchronized with the dark phase of the illumination cycle. Nocturnal emergence would represent an adaptation reducing vulnerability to visual predators. Previous work has shown that in Newfoundland, capelin emergence from intertidal beaches is triggered by abrupt changes in water temperature following the sporadic advection to the coast of surface water masses characterized by low predator and high prey abundances. We argue that regional differences in the emergence pattern of the species represent different strategies to avoid predation at the onset of the planktonic drift when the vulnerable yolk sac larvae are densely aggregated. Selection acting on the behaviour of the early larval stages could contribute to stock differentiation in capelin.

Seasonal distribution, abundance, and growth of larval capelin (Mallotus villosus) and the role of the Lower Estuary (Gulf of St. Lawrence, Canada) as a nursery area

2013 ◽  
Vol 70 (10) ◽  
pp. 1508-1530 ◽  
Author(s):  
Patrick Ouellet ◽  
Alice Olga Victoria Bui ◽  
Diane Lavoie ◽  
Joël Chassé ◽  
Nicolas Lambert ◽  
...  
Keyword(s):  
Size Structure ◽  
Larval Growth ◽  
Lower Estuary ◽  
Mallotus Villosus ◽  
Lawrence Estuary ◽  
Particle Tracking Model ◽  
Capelin Mallotus Villosus ◽  
Tracking Model ◽  
St Lawrence Estuary

Capelin (Mallotus villosus) spawning in the St. Lawrence Estuary is concentrated in the Upper Estuary (UE). The northwest Gulf of St. Lawrence (NW GSL) was presented as the principal nursery for capelin originating from the estuary. In 2009 and 2010, we investigated the abundance, distribution, and size structure of capelin larvae in this system, and a particle tracking model was used to simulate larval dispersion. There was evidence of retention and larval growth in the Lower Estuary (LE), and older larvae were found in the LE by the end of summer. In October 2009, it was possible to link the cohorts of large larvae to emergence events in the UE in spring. Capelin larvae were more abundant or bigger (mean length) in the LE relative to the NW GSL in fall 2006, 2008, and 2009. We conclude that the LE is the habitat of a unit of the GSL capelin population composed of individuals that are retained in this region following hatching in the UE and that there is limited mixing with larvae originating in the NW GSL.

Parasites of capelin (Mallotus villosus) in the St. Lawrence estuary and gulf

1995 ◽  
Vol 52 (S1) ◽  
pp. 246-253 ◽  
Author(s):  
J.R. Arthur ◽  
E. Albert ◽  
F. Boily
Keyword(s):  
Parasite Fauna ◽  
Mallotus Villosus ◽  
New Host ◽  
Lawrence Estuary ◽  
Pseudoterranova Decipiens ◽  
Capelin Mallotus Villosus ◽  
High Level ◽  
St Lawrence Estuary ◽  
Hysterothylacium Aduncum ◽  
New Host Records

A survey of the parasites of capelin (Mallotus villosus) caught on the spawning grounds at five localities in the estuary of the St. Lawrence River and the Gulf of St. Lawrence, Canada, was conducted in 1994. From examination of 125 fish, a total of 21 parasite taxa was identified (2 Protista, 3 Monogenea, 4 Digenea, 4 Cestoda, 7 Nematoda, and 1 Acanthocephala). Seven new host records are reported for this fish (Trichodina sp., Brachyphallus crenatus, Bothrimonus sturionis, Ascarophis sp., Pseudoterranova decipiens larva, Spirurida gen.sp. larva, and Echinorhynchus laurentianus). The parasite fauna of capelin is comparatively depauperate. It is characterized by the relative abundance of a few species showing a high level of host specificity (Microsporidium sp., Trichodina sp., Gyrodactyloides andriaschewi, G. petruschewskii, Laminiscus gussevi, and Eubothrium parvum) that mature on or in capelin, several ubiquitous adult digeneans (e.g., B. crenatus, Derogenes various, Hemiurus levinseni, and Lecithaster gibbosus), and a number of species that use capelin as intermediate or transport hosts (e.g., Scolex pleuronectis plerocercoid, Anisakis simplex larva, Contracaecinea gen.sp. larva, and Hysterothylacium aduncum larva).

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

1998 ◽  
Vol 76 (8) ◽  
pp. 1411-1417 ◽  
Author(s):  
Réjean Hays ◽  
Lena N Measures ◽  
Jean Huot
Keyword(s):  
Anisakis Simplex ◽  
Clupea Harengus ◽  
Delphinapterus Leucas ◽  
Intermediate Hosts ◽  
Mallotus Villosus ◽  
Lawrence Estuary ◽  
Third Stage ◽  
Capelin Mallotus Villosus ◽  
Paratenic Hosts ◽  
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.

Seasonal Variation in the Diet of Harp Seals (Phoca groenlandica) from the Gulf of St. Lawrence and Western Hudson Strait

1993 ◽  
Vol 50 (7) ◽  
pp. 1363-1371 ◽  
Author(s):  
Gregor Gilpin Beck ◽  
Michael O. Hammill ◽  
Thomas G. Smith
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Stomach Contents ◽  
Fish Prey ◽  
Lawrence Estuary ◽  
Phoca Groenlandica ◽  
Capelin Mallotus Villosus ◽  
Gross Energy ◽  
St Lawrence Estuary ◽  
Magdalen Islands

Of 247 harp seal (Phoca groenlandica) stomachs collected between December 1988 and October 1990 from western Hudson Strait (autumn), the northern Gulf of St. Lawrence (December), the St. Lawrence estuary (winter and April), and the Magdalen Islands (March), 140 (57%) contained food. The Magdalen Islands sample contained significantly more empty stomachs (62%, n = 164) than those from all other locations. Both the unreconstructed mass of stomach contents and the proportion of fish and invertebrate prey within individual stomachs varied significantly with location and season. Harp seals obtained from the northern Gulf of St. Lawrence during their southward migration fed less intensively, and on a wider variety of both invertebrate and fish prey, notably Parathemisto libellula, Pandalus sp., sand lance (Ammodytes sp.), and Atlantic cod (Gadus morhua). Feeding was more intensive and specialized in Hudson Strait and the St. Lawrence estuary where capelin (Mallotus villosus) dominated in the diet. Capelin contributed 89 and 98% of gross energy in samples from Hudson Strait (1990) and the estuary (April). The number of capelin per stomach consumed by seals from the St. Lawrence estuary in April was high (169.4 ± 58.9, mean ± SD, n = 9). The mean estimated lengths of capelin and cod consumed were 132 and 140 mm.

Channel head dynamics: capelin (Mallotus villosus) aggregation in the tidally driven upwelling system of the Saguenay - St. Lawrence Marine Park's whale feeding ground

2002 ◽  
Vol 59 (2) ◽  
pp. 197-210 ◽  
Author(s):  
Yvan Simard ◽  
Diane Lavoie ◽  
François J Saucier
Keyword(s):  
Circulation Model ◽  
Feeding Strategies ◽  
Total Biomass ◽  
Balaenoptera Acutorostrata ◽  
Mallotus Villosus ◽  
Tidal Dynamics ◽  
Lawrence Estuary ◽  
Fin Whale ◽  
Capelin Mallotus Villosus ◽  
Tidally Driven

Capelin (Mallotus villosus) tridimensional distribution at the head of the Laurentian Channel in the St. Lawrence estuary was investigated using 38- and 120-kHz acoustic surveys in the summers of 1994, 1995, 1997, and 1998. The results are interpreted with the help of a high-resolution tridimensional tidal circulation model. Total biomasses were small (93–4583 t) and showed rapid fluctuations, whereas mesoscale distribution was more constant. Capelin tended to occupy the very end of the channel head, especially the slopes and shallows surrounding the basins. This pattern did not coincide with the krill distribution, but the two total biomass series were significantly correlated. Capelin tidal dynamics is characterized by herding of capelin against the channel head slopes by the starting flooding currents, followed by an upwelling over the sills and shallows during maximum flood currents, and a return to the channel by the surface outflow during ebb. Each side of the channel head has a distinct capelin retention tidal cycle involving passive advection, swimming, and the two-layer estuarine circulation. This capelin distribution and tidal dynamics closely match the local fin whale (Balaenoptera physalus) and minke whale (Balaenoptera acutorostrata) distributions observed from the whale-watching fleet and typical tidal feeding strategies at the channel head.

Le Panache du Saguenay

1983 ◽  
Vol 40 (1) ◽  
pp. 52-60 ◽  
Author(s):  
J. Lebel ◽  
E. Pelletier ◽  
M. Bergeron ◽  
N. Belzile ◽  
G. Marquis
Keyword(s):  
Surface Layer ◽  
Deep Water ◽  
High Tide ◽  
Lawrence Estuary ◽  
Fresh Waters ◽  
Saguenay Fjord ◽  
Region Data ◽  
Saguenay River ◽  
St Lawrence Estuary ◽  
St Lawrence River

The large difference between the alkalinity of the fresh waters of the St. Lawrence River (1.475 mmol∙kg−1) and the Saguenay River (0.134 mmol∙kg−1) was used to locate the region on the St. Lawrence estuary which is under the influence of the Saguenay River. This method has the advantage over classical measurements such as salinity and temperature that it is independent of the upwelling of deep water in this region. Data was obtained in the St. Lawrence estuary near the mouth of the Saguenay fjord using a network of 33 stations at slack low tide and 23 stations at slack high tide. The results show that, at low tide, Saguenay water forms a plume which extends more than 10 km from the mouth of the fjord into the estuary. At high tide the plume is restricted to the surface layer as the Saguenay waters are pushed back into the fjord.

Le contrôle de la variabilité à court terme du phytoplancton estuarien: stabilité verticale et profondeur critique

1979 ◽  
Vol 36 (11) ◽  
pp. 1325-1335 ◽  
Author(s):  
L. Fortier ◽  
L. Legendre
Keyword(s):  
Water Column ◽  
Tidal Cycle ◽  
Richardson Number ◽  
Low Frequency ◽  
The Other ◽  
Critical Depth ◽  
Lawrence Estuary ◽  
Vertical Stability ◽  
St Lawrence Estuary ◽  
C Assimilation

Hourly series of summer phytoplankton biomass (ATP and chlorophyll a) and photosynthetic capacity (14C assimilation and ATP increase in saturating light) were sampled in the lower St. Lawrence Estuary during the summer of 1977. Vertical stability of the water column was estimated by the Richardson number. From the results it is concluded that the mean level of biomass is an inverse function of critical depth, likely linked to the neap-spring tidal cycle (Mf). On the other hand, the fine fluctuations of biomass and photosynthetic activity were related to vertical stability, which varies according to the semi-diurnal tidal cycle (M2). A simple model was developed on the basis of Sverdrup's critical depth, combining the M2 fluctuations in stability (degree of vertical mixing) to Mf variations in critical depth. Net biomass increases, observed in a nonturbid stabilized water column, cannot be explained by the growth rates computed from 14C assimilation, but they are consistent with the measured rates of ATP production. Spectral analyses of time series of temperature and Richardson number suggest that low frequency water column stability variations amplify the spatial heterogeneity of a reacting parameter such as phytoplankton. On the other hand, a passive scalar such as temperature does not respond to these low frequency variations of stability. It follows that the study of stability spectra may give some insight into the low frequency control of phytoplankton dynamics. Key words: phytoplankton, St. Lawrence Estuary, variability, vertical stability, critical depth, Richardson number, Kendall's cross correlation, spectral analysis

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