Predation on marine-phase Atlantic salmon (Salmo salar) by gannets (Morus bassanus) in the Northwest Atlantic

2002 ◽  
Vol 59 (4) ◽  
pp. 602-612 ◽  
Author(s):  
W A Montevecchi ◽  
D K Cairns ◽  
R A Myers

Predation on Atlantic salmon (Salmo salar) has been recorded in rivers and estuaries, but there is little documentation of predation at sea. Prey landed by gannets (Morus bassanus) over 24 years in a large colony off northeast Newfoundland included small proportions of post-smolt Atlantic salmon. Before 1990, when shifts in oceanographic conditions and pelagic food webs occurred in the Labrador Sea, post-smolts, on average, made up 0.29% of estimated intake by gannets during August 1977–1989. In contrast, during the 1990s, this estimate increased to 2.53%, peaking at 6.37% in 1993. Model estimates with wide error margins projected that gannets consumed a mean of 1.6 t and 19.2 t of post-smolts during August 1977–1989 and 1990–2000, respectively, making up 0.22% and 2.70% of estimated North American post-smolt biomass during these periods. The migratory routes of post-smolt Atlantic salmon pass through the foraging ranges of gannet colonies, but limited sampling at colonies other than Funk has not revealed salmon in gannet diets. Sampling seabird diets is an economic, biological means of investigating the ecology and natural mortality of Atlantic salmon. Spatial and temporal expansion of this sampling would enhance its oceanographic context and reduce uncertainty associated with estimates of predation by seabirds.

1991 ◽  
Vol 48 (1) ◽  
pp. 2-6 ◽  
Author(s):  
D. G. Reddin ◽  
P. B. Short

In order to learn more about the existence, abundance, and distribution of postsmolt Atlantic salmon (Salmo salar) in the Labrador Sea, exploratory fishing was done with surface-set gill nets in early autumn of 1987 and 1988. In total, there were 468 salmon of various sea ages captured, of which 207 were postsmolts. The high catch rates compared with catch rates from Greenland suggest that the population of postsmolts in the Labrador Sea may be large. Postsmolts from rivers in Maine to Labrador were caught in the Labrador Sea, as indicated by Carlin tags and river age distribution from scale reading. The highest catch rates of postsmolts occurred in the Labrador Sea between 56° and 58°N latitude.


2013 ◽  
Vol 70 (7) ◽  
pp. 1011-1030 ◽  
Author(s):  
Gilles L. Lacroix

Pop-up satellite archival tags identified differences in oceanic migration of Atlantic salmon (Salmo salar) kelts from three distinct Canadian populations. Kelts from two endangered populations were restricted to coastal areas near home rivers, whereas kelts from a persisting nearby population migrated to the Labrador Sea and towards the Flemish Cap. Kelts spent most time near the surface (0–5 m), but coastal migrants undertook repeated daytime dives (10–40 m), associated with feeding, upon marine entry and progress was slow (8–23 km·day−1). Distant migrants moved rapidly along the continental shelf (10–50 km·day−1) against prevailing ocean currents, remaining near the surface, except for deep dives (100–1000 m) when crossing ocean channels and at the shelf edge. Home range water temperatures (0–15 °C) indicated that kelts avoided warmer adjacent areas in summer. Kelts did not avoid cold coastal habitat (0–5 °C) in winter, but avoided the surface layers. Kelt migration mimicked that of postsmolts of similar origins, with water temperature acting as a directive or controlling factor. Containment of kelts from endangered populations in coastal habitat was probably responsible for the disappearance of repeat spawners.


2018 ◽  
Vol 10 (12) ◽  
pp. 4814
Author(s):  
Bong-Tae Kim

The purpose of this study is to examine how the competitive advantage on international markets based on sustainable production is reflected in the pricing behavior of farmed fish, using Norwegian Atlantic salmon (Salmo salar) as an example. The salmon is widely consumed and highly traded due to the rapid development of aquaculture. Norway, which has been successful in regulating and innovating for sustainable aquaculture, accounts for more than half of world production. A model dealing with pass-through of exchange rates and tariff rates based on the exporter’s profit maximization was applied to 28 major countries importing from Norway, using yearly panel data for 2000–2016. Significant evidence of price discrimination was observed in Asian countries where Norway has a high market share, such as China, South Korea, Thailand, and Vietnam. This implies that the market structure of imperfect competition played a major role, suggesting the need to diversify imports to transform the market structure in favor of consumers in Asian countries. Research on the pricing behavior of fisheries products, including cultured fish, is limited in international trade. This paper addresses the gap by applying the pass-through model with changes in tariff rate as well as exchange rate.


1971 ◽  
Vol 28 (8) ◽  
pp. 1199-1203
Author(s):  
W. H. Lear ◽  
A. W. May

Twenty Paralepis specimens were taken from the stomachs of 10 Atlantic salmon (Salmo salar L.) caught by drift net at seven fishing stations in the Davis Strait and Labrador Sea. Eleven of the 20 specimens were identified as Paralepis coregonoides borealis Reinhardt on the basis of vertebral counts, and the remainder are tentatively assigned to this species. These are the first records of adult specimens from the Davis Strait, though a few have been recorded from the west coast of Greenland.


2001 ◽  
Vol 32 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Sjofn Sigurgisladottir ◽  
Margret S. Sigurdardottir ◽  
Helga Ingvarsdottir ◽  
Ole J. Torrissen ◽  
Hannes Hafsteinsson

2005 ◽  
Vol 68 (7) ◽  
pp. 1336-1339 ◽  
Author(s):  
L. L. NESSE ◽  
T. LØVOLD ◽  
B. BERGSJØ ◽  
K. NORDBY ◽  
C. WALLACE ◽  
...  

The objective of our experiments was to study the persistence and dissemination of orally administered Salmonella in smoltified Atlantic salmon. In experiment 1, salmon kept at 15°C were fed for 1 week with feed contaminated with 96 most-probable-number units of Salmonella Agona per 100 g of feed and then starved for 2 weeks. Samples were taken from the gastrointestinal tract and examined for Salmonella 1, 2, 8, 9, 15, and 16 days after the feeding ended. In experiment 2, Salmonella Agona and Montevideo were separately mixed with feed and administered by gastric intubation. Each fish received 1.0 × 108, 1.0 × 106, or 1.0 × 104 CFU. The different groups were kept in parallel at 5 and 15°C and observed for 4 weeks. Every week, three fish in each group were sacrificed, and samples were taken from the skin, the pooled internal organs, the muscle, and the gastrointestinal tract and examined for the presence of Salmonella. The results from the two experiments showed that the persistence of Salmonella in the fish was highly dependent on the dose administered. Salmonella was not recovered from any of the fish that were fed for 1 week with the lowest concentration of Salmonella. In the fish given the highest dose of Salmonella, bacteria persisted for at least 4 weeks in the gastrointestinal tract as well as, to some extent, the internal organs. The present study shows that under practical conditions in Norway, the risk of Salmonella in fish feed being passed on to the consumer of the fish is negligible.


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