Feeding of Atlantic salmon (Salmo salar L.) postsmolts in a fjord in central Norway

1994 ◽  
Vol 72 (5) ◽  
pp. 834-839 ◽  
Author(s):  
C. D. Levings ◽  
N. A. Hvidsten ◽  
B. Ø. Johnsen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Larval Fish ◽  
Feeding Habits ◽  
Stomach Contents ◽  
Calanoid Copepods ◽  
Atlantic Salmon Salmo Salar

The feeding habits of postsmolt Atlantic salmon (Salmo salar) caught by two-boat trawling were studied in Trondheimsfjord in central Norway. Fish caught in the inner fjord near the estuaries of the Orkla and Gaula rivers had recently fed on food produced in freshwater and estuarine habitats, namely stonefly and mayfly nymphs and gammarid amphipods. Stomach contents of postsmolts caught farther seaward were dominated by adult insects, with smaller proportions of the food volume originating from marine pelagic (larval fish, hyperiid amphipods, calanoid copepods) and nearshore (gammarid amphipods) habitats.

Feeding by Hatchery-Reared and Wild Atlantic Salmon (Salmo salar) Parr in Streams

1979 ◽  
Vol 36 (11) ◽  
pp. 1408-1412 ◽  
Author(s):  
A. J. Sosiak ◽  
R. G. Randall ◽  
J. A. McKenzie
Keyword(s):  
Atlantic Salmon ◽  
Key Words ◽  
Salmo Salar ◽  
Food Selection ◽  
Stomach Contents ◽  
Stomach Fullness ◽  
Size Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Feeding Experience ◽  
Salmon Parr

Hatchery-reared Atlantic salmon (Salmo salar) parr were captured 1–3 mo after release in streams, along with wild parr from the same streams. Identification of their stomach contents showed total number of organisms and number of taxa per stomach were greater and there was a higher index of stomach fullness in wild than in hatchery parr resident ≤ 2 mo in a stream. Wild parr consumed more Brachycentridae, Hydroptilidae, Diptera, and Plecoptera than did hatchery parr, but sometimes less Odontoceridae and Heptageniidae. These differences may have arisen from size-dependent food selection, the effects of feeding experience, or possible microhabitat differences between wild and hatchery parr. Key words: salmon parr, hatchery-reared, wild, feeding

scholarly journals Allometry of diet selectivity in juvenile Atlantic salmon (Salmo salar)

1997 ◽  
Vol 54 (8) ◽  
pp. 1894-1902 ◽  
Author(s):  
E R Keeley ◽  
JWA Grant
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Fork Length ◽  
Stomach Contents ◽  
Optimal Size ◽  
Atlantic Salmon Salmo Salar ◽  
Paired Samples ◽  
Selective Foraging ◽  
Juvenile Atlantic Salmon ◽  
Prey Length

Juvenile salmonids in streams typically feed on larger invertebrates than the average size available in the drift. Our objective was to describe the allometry of this size-selective foraging in juvenile Atlantic salmon, Salmo salar of Catamaran Brook, New Brunswick. We compared paired samples of the stomach contents of 46 salmon (age 0 + to 2 + ; fork length 2.9-14.5 cm) with drift samples collected from their feeding territories. Juvenile salmon fed opportunistically on all major types of invertebrates in the drift, except for water mites (Hydracarina). However, newly emerged salmon fed on smaller prey than the average available in the drift, primarily chironomid larvae, whereas salmon larger than 4.6 cm fed on larger prey than average, primarily dipteran adults and pupae. Larger salmon ate larger prey. Minimum prey length in stomachs was well predicted by gill raker spacing, but mean prey width was only one third of the optimal size and maximum prey width was much less than mouth width. The allometry of prey size appeared to be related primarily to an increase in size-selective foraging with increasing body size, rather than to morphological constraints. Juvenile Atlantic salmon in our study ate smaller prey than similar-sized salmonids in other studies.

The feeding behaviour of cultured and wild Atlantic salmon, Salmo salar L., in the Louvenga River, Kola Peninsula, Russia

2006 ◽  
Vol 63 (7) ◽  
pp. 1297-1303 ◽  
Author(s):  
Alexander V. Orlov ◽  
Yuri V. Gerasimov ◽  
Oleg M. Lapshin
Keyword(s):  
Atlantic Salmon ◽  
Water Column ◽  
Salmo Salar ◽  
Feeding Habits ◽  
Poor Quality ◽  
Wild Fish ◽  
Food Items ◽  
Atlantic Salmon Salmo Salar ◽  
Cultured Fish ◽  
Terrestrial Insects

Abstract An underwater survey was conducted in the Louvenga River to investigate the behaviour and distribution of juvenile Atlantic salmon, Salmo salar L., and the adaptation of cultured fish to the natural environment. The food and feeding habits of 34 wild and 44 cultured parr released from the Kandalaksha hatchery were also studied. The cultured salmon fed mostly in the bottom 15 cm of the water column in current velocities of 0.2–0.35 m s−1. In contrast to wild fish, when cultured fish moved away from these areas and into areas with higher current velocities (average speeds of 0.52 m s−1) and lower drift density (2.66 particles m−3), they did not show a tendency to return to slower moving water. The diet of cultured parr was made up of benthic invertebrates (20%), terrestrial insects (32%), and drift items (33%), but these proportions were different in the diet of wild parr (2%, 24%, and 67%, respectively), with drift items predominating. The mean quantity of food per stomach indicated that the wild parr were feeding more actively than cultured parr. Invertebrates made up 3% of items in the drift, with the remaining 97% being exuvia of aquatic and terrestrial insects, algae, and various plant remains. Poor quality food items were found in 13% and 25% of the stomachs of wild and cultured parr, respectively, demonstrating that the cultured parr were less able to differentiate food items in the water column and made 20–30% more false feeding attempts than wild fish. The cultured parr were also more aggressive in terms of the frequency of aggressive interactions and reacted to each other at greater distances than wild fish. Thus, wild parr were able to optimize their feeding conditions by choosing habitats with preferred sizes of food items, higher densities of drift items, and current velocities that allowed them to maintain station and to feed more effectively. Conversely, cultured parr usually occupied suboptimal areas.

Predation on stocked Atlantic salmon (Salmo salar) fry

2003 ◽  
Vol 60 (1) ◽  
pp. 32-42 ◽  
Author(s):  
J Nathan Henderson ◽  
Benjamin H Letcher
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Salmo Trutta ◽  
Stomach Contents ◽  
Predation Rate ◽  
Predator Species ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Fry ◽  
Consumption Rates ◽  
Abiotic And Biotic Factors

We studied predator–prey interactions between juvenile Atlantic salmon (Salmo salar) and trout in three Massachusetts, U.S.A., streams and in artificial streams. We sampled stomach contents of age-1+ and older salmon and trout (Salvelinus fontinalis, Salmo trutta) following salmon fry stocking in the spring of 1997 and 1998. Between 4.3 and 48.6% of the stocked fry were consumed within the first 2 days after stocking, and total fry mortality from predation varied from 4.3 to 60.7%. No significant differences were found between stomach weights of predators ( without fry weight) that consumed fry and those that did not. Artificial stream experiments testing effects of habitat complexity and predator species on predator consumption rates revealed that consumption rates were not different between brook (S. fontinalis) and brown (S. trutta) trout (p = 0.59). Predation rate tended to decrease as the percentage of riffle habitat increased but the decrease was not significant (p = 0.22). Our results indicate that predation on stocked Atlantic salmon fry can be substantial (up to 60%), appears to be short lived (2 days), and is not related in a simple way to abiotic and biotic factors.

Winter growth and survival of juvenile Atlantic salmon (Salmo salar) in experimental raceways

2004 ◽  
Vol 61 (12) ◽  
pp. 2350-2357 ◽  
Author(s):  
Donna L Parrish ◽  
Ethan J Hawes ◽  
Kevin G Whalen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Stomach Contents ◽  
Distinct Advantage ◽  
Caloric Content ◽  
Lower Velocity ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Mature Parr ◽  
In The Wild

We used experimental raceways to determine overwinter mortality of wild-reared immature and mature post-young-of-the-year Atlantic salmon (Salmo salar). Secondarily, we investigated the effects of differing treatments (velocity and shelter) on winter growth and survival. Overall survival from November to April was 94%, and survival of immature (98%) and mature (90%) parr, although statistically different, was very similar. Immature parr grew more in length than mature parr, and both immature and mature parr in higher velocity (12 cm·s–1) raceways grew more than those in lower velocity (0.6 cm·s–1) raceways. Stomach contents were twofold greater in parr occupying higher velocity raceways than those in lower velocity raceways. Caloric content of immature and mature parr did not differ in any of five monthly samples. Lowest caloric content occurred in early February and increased between February and March when water temperatures were well below those considered optimal for growth. Although ice cover was present, isolating parr from conditions that occur in natural settings may have helped parr achieve nearly 2.5 times greater survival than parr in the wild. Further, whereas previous studies showed parr select habitats to minimize energetic loss, our results show a distinct advantage for parr to expend energy to feed during winter.

Microstructure and texture of fresh and smoked Atlantic salmon, Salmo salar L., fillets from fish reared and slaughtered under different conditions

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