Seasonal variation in size-dependent survival of juvenile Atlantic salmon (Salmo salar): performance of multistate capture–mark–recapture models

2008 ◽  
Vol 65 (8) ◽  
pp. 1649-1666 ◽  
Author(s):  
Benjamin H. Letcher ◽  
Gregg E. Horton
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Mark Recapture ◽  
Size Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Average Survival ◽  
Average Probability ◽  
Sampling Intervals ◽  
Time Invariant ◽  
Probability Of Capture

We estimated the magnitude and shape of size-dependent survival (SDS) across multiple sampling intervals for two cohorts of stream-dwelling Atlantic salmon ( Salmo salar ) juveniles using multistate capture–mark–recapture (CMR) models. Simulations designed to test the effectiveness of multistate models for detecting SDS in our system indicated that error in SDS estimates was low and that both time-invariant and time-varying SDS could be detected with sample sizes of >250, average survival  of >0.6, and average probability of capture of >0.6, except for cases of very strong SDS. In the field (N ∼750, survival 0.6–0.8 among sampling intervals, probability of capture 0.6–0.8 among sampling occasions), about one-third of the sampling intervals showed evidence of SDS, with poorer survival of larger fish during the age-2+ autumn and quadratic survival (opposite direction between cohorts) during age-1+ spring. The varying magnitude and shape of SDS among sampling intervals suggest a potential mechanism for the maintenance of the very wide observed size distributions. Estimating SDS using multistate CMR models appears complementary to established approaches, can provide estimates with low error, and can be used to detect intermittent SDS.

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 Atlantic salmon (Salmo salar) smolt and early post-smolt migration and survival inferred from multi-year and multi-stock acoustic telemetry studies in the Gulf of St. Lawrence, northwest Atlantic

2018 ◽  
Vol 76 (4) ◽  
pp. 1107-1121 ◽  
Author(s):  
Gérald Chaput ◽  
Jonathan Carr ◽  
Jason Daniels ◽  
Steve Tinker ◽  
Ian Jonsen ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Survival Rates ◽  
Fork Length ◽  
Probability Of Survival ◽  
Size Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Key Points ◽  
Migration Dynamics

Abstract The migration dynamics and inter-annual variation in early at-sea survival of Atlantic salmon (Salmo salar) smolts over 14 years of study are reported for four river populations located in the Gulf of St. Lawrence (Canada). Acoustically tagged smolts were monitored at three points along their migration from freshwater to the Labrador Sea, a migration extending more than 800 km at sea and a period of 2 months. A hierarchical state-space version of the Cormack–Jolly–Seber model was used to estimate apparent survival rates from incomplete acoustic detections at key points. There was a positive size-dependent probability of survival through the freshwater and estuary areas; the odds of survival of a 16 cm smolt were 1.5–1.7 times higher than for a 13.5 cm smolt, length at tagging. Length adjusted (centred to the mean fork length of smolts during the study of 14.6 cm) survivals through the estuary and nearshore waters were estimated to range between 67 and 90% for the two river populations migrating through Chaleur Bay in contrast to lower survival estimates of 28–82% for the two populations from the neighbouring Miramichi Bay. Across the 14 years of study, survival estimates varied without trend for the populations of Chaleur Bay, but declined for the populations migrating through Miramichi Bay. Survival through the Gulf of St. Lawrence was variable but generally high among years and rivers, ranging from 96% day−1 to 99% day−1. Long term, replicated studies at multiple sites using acoustically tagged smolts can provide empirical data to examine hypotheses of the location and timing of factors contributing to smolt and post-smolt mortality of salmon at sea.

scholarly journals Influences of migration phenology on survival are size-dependent in juvenile Atlantic salmon (Salmo salar)

2017 ◽  
Vol 95 (8) ◽  
pp. 581-587 ◽  
Author(s):  
B. Jonsson ◽  
M. Jonsson ◽  
N. Jonsson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Risk Environment ◽  
Migratory Species ◽  
Long Distance ◽  
Size Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Short Period ◽  
Migration Phenology ◽  
Migration Event

Long-distance migratory species can reduce mortality risks by synchronizing the migration event and create confusion by swamping predators with high densities. To reduce confusion, predators are known to primarily select aberrant prey. We hypothesized that at the start of their sea sojourn, particularly small and large Atlantic salmon (Salmo salar L., 1758) would spread the risk by also migrating at other times of the year. Based on data from the Norwegian river Imsa between 1976 and 2015, we found that juveniles, 14–19 cm in total length, started their sea sojourn during a short period between late April and early June. However, more than 20% of fish 13 cm or shorter migrated downstream between October and March, whereas 55% of fish 20 cm or longer migrated downstream between July and September. The regular-sized, spring-migrating juveniles had 2–3 times higher survival at sea than similar-sized conspecifics migrating to sea at other times of the year. The survival at sea for smaller juveniles was not improved by migration in spring relative to winter, and the survival of the largest juveniles was similar in spring and summer. Thus, the migration phenology appears adapted to survival in a high-risk environment by changing the timing according to their sizes.

Viability and Freshwater Performance of Atlantic Salmon (Salmo salar) × Brown Trout (Salmo trutta) Triploid Hybrids

1994 ◽  
Vol 51 (S1) ◽  
pp. 16-24 ◽  
Author(s):  
Peter F. Galbreath ◽  
Gary H. Thorgaard
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Atlantic Salmon Salmo Salar ◽  
Average Survival ◽  
Brown Trout Salmo Trutta ◽  
Made In

Survival to initiation of feeding and early freshwater growth were measured for both diploid (2N) and triploid (3N) Atlantic salmon (Salmo salar) and 2N and 3N hybrids between female Atlantic salmon and male brown trout (Salmo trutta) to evaluate the triploid hybrid's potential for commercial culture. Crosses were made in 1990 and 1991 and triploidy was induced by heat shock. Average survival to initiation of feeding generally did not differ among the 2N Atlantic salmon and hybrids within years, nor between the 3N crosses within years. Average survival to initiation of feeding of the 3N Atlantic salmon and hybrids relative to the corresponding 2N crosses was reduced by 2 and 9%, respectively, in 1990, and by 55 and 62%, respectively, in 1991. Five freshwater growth trials were conducted to compare the different crosses. Results indicated no consistent differences in relative growth rates, although the hybrids demonstrated greater variability in growth at age 0+.

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

Persistence of Orally Administered Salmonella enterica Serovars Agona and Montevideo in Atlantic Salmon (Salmo salar L.)

2005 ◽  
Vol 68 (7) ◽  
pp. 1336-1339 ◽  
Author(s):  
L. L. NESSE ◽  
T. LØVOLD ◽  
B. BERGSJØ ◽  
K. NORDBY ◽  
C. WALLACE ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Salmonella Enterica ◽  
Most Probable Number ◽  
Fish Feed ◽  
Internal Organs ◽  
Probable Number ◽  
Atlantic Salmon Salmo Salar ◽  
Gastric Intubation

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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