Managed Metapopulations: Do Salmon Hatchery ‘Sources’ Lead to In-River ‘Sinks’ in Conservation?

Several population parameters (length and dynamics of spawning run, size-sex composition, variability of morphological and physiological characteristics) are determined and indices of survival are calculated for the pink salmon hatchery stocks from the Aniva Bay of the 2008-2011 generations on the base of the cultured pink salmon differentiation by thermal marks on otoliths. The hatchery pink salmon begin their migration to the bay rivers in late July, together with the wild fish. Size-weight parameters of the fish and their variability are similar for the hatchery and wild stocks in this period, obviously because of low impact of hatcheries on natural reproduction and high portion of wild fish among the spawners used in the hatcheries (> 50 %). Mean portion of the hatchery-reared pink salmon on spawning grounds of the main rivers was 17.9 % in the 2010-2013, the coefficients of their return varied from 1.0 % to 6.4 % that was lower than for the wild fish.

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Density-Dependence at Sea for Coho Salmon (Oncorhynchus kisutch)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f90-200 ◽

1990 ◽

Vol 47 (9) ◽

pp. 1765-1772 ◽

Cited By ~ 24

Author(s):

J. M. Emlen ◽

R. R. Reisenbichler ◽

A. M. McGie ◽

T. E. Nickelson

Keyword(s):

Density Dependence ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Density Dependent ◽

Density Dependent Mortality ◽

Hatchery Fish ◽

Statistical Assumptions ◽

Diminishing Returns ◽

Salmon Hatchery ◽

Dependent Mortality

The success of expanded salmon hatchery programs will depend strongly on the degree of density-induced diminishing returns per smolt released. Several authors have addressed the question of density-dependent mortality at sea in coho salmon (Oncorhynchus kisutch), but have come to conflicting conclusions. We believe there are compelling reasons to reinvestigate the data, and have done so for public hatchery fish, using a variety of approaches. The results provide evidence that survival of these public hatchery fish is negatively affected, directly by the number of public hatchery smolts and indirectly by the number of private hatchery smolts. These results are weak, statistically, and should be considered primarily as a caution to those who, on the basis of other published work, believe that density-dependence does not exist. The results reported here also re-emphasize the often overlooked point that inferences drawn from data are strongly biased by investigators' views of how the systems of interest work and by the statistical assumptions they make preparatory to the analysis of those data.

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Advances in Fish Tagging and Marking Technology

Advances in Fish Tagging and Marking Technology ◽

10.47886/9781934874271.ch19 ◽

2012 ◽

Keyword(s):

Sockeye Salmon ◽

Release Site ◽

Migratory Fish ◽

The Poor ◽

The Pacific ◽

Significant Difference ◽

Haplotype Frequencies ◽

Acoustic Tags ◽

The Pacific Ocean ◽

Salmon Hatchery

<i>Abstract</i>.—We investigated the marine migratory behavior and survival of Sakinaw Lake sockeye salmon <i>Oncorhynchus nerka </i>during their outbound migration as juveniles and return migration as adults two or more years later by tracking individuals that had been implanted with Vemco acoustic tags programmed to have two periods of active transmission. We tracked both hatchery-reared anadromous sockeye salmon (‘hatchery sockeye’) and wild nonanadromous ‘kokanee,’ two genetically-distinct, sympatric ecotypes inhabiting Sakinaw Lake, British Columbia. Tagged kokanee were distinguished from wild sockeye by haplotype frequencies at two mitochondrial DNA genes. Migrations were inferred from detections by the Pacific Ocean Shelf Tracking (POST) receivers, and supplemental tracking near the release site and in Sakinaw Lake. We found no significant differences between the ecotypes in the proportion of ‘migratory’ fish (those detected migrating seaward by POST telemetry in the year of release, 42% of all 254 fish released) or in the proportion of ocean-going fish (those detected at receivers near the open ocean, 20% of all fish released). Seaward migration in both ecotypes was primarily northward through Johnstone Strait in 2 of the 3 years studied (92% of migratory fish in 2004 and 84% in 2006). A significantly higher proportion of fish moved southward in 2005 (45% of migratory fish) than in 2004 or 2006, but this difference could not be attributed to ecotype, body size, or release date. One significant difference observed between the ecotypes was that 6 kokanee but no sockeye migrated back into Sakinaw Lake within 2 weeks of release in 2006. The number of tagged fish detected as returning adults with operational tags was low (3 sockeye at the release site and 2 kokanee at Sakinaw Creek), but none of these fish had been detected crossing seaward POST lines as juveniles and thus appeared to be nonmigratory. The adult return rate of these nonmigratory tagged fish (3.4% in sockeye, 4.3% in kokanee) was higher than for migratory tagged fish (0% for both ecotypes). This discrepancy suggests that factors outside the Strait of Georgia have caused the poor marine survival that is preventing recovery of the endangered Sakinaw sockeye population (mean <0.2% since 2003).

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A review of Pacific salmon hatchery programmes on Hokkaido Island, Japan

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2006.03.024 ◽

2006 ◽

Vol 63 (7) ◽

pp. 1353-1363 ◽

Cited By ~ 47

Author(s):

Kentaro Morita ◽

Toshihiko Saito ◽

Yasuyuki Miyakoshi ◽

Masa-aki Fukuwaka ◽

Toru Nagasawa ◽

...

Keyword(s):

Adaptive Learning ◽

Pacific Salmon ◽

Pink Salmon ◽

Active Regions ◽

Masu Salmon ◽

Learning Approaches ◽

Management Tools ◽

Salmon Hatchery ◽

Species Specific ◽

Hokkaido Island

Abstract Hatchery programmes involving the mass release of cultured fish have been implemented worldwide to supplement wild populations and to increase harvests. Hokkaido Island is one of the most active regions for Pacific salmon hatchery programmes, with ca. 1.2 billion (109) juveniles released annually along a coastline of ca. 3000 km. During the last quarter of the 20th century, coastal catches of chum and pink salmon increased dramatically, whereas those of masu salmon did not. In addition to the development of hatchery technologies, several possible hypotheses may explain these catch trends, including climate change, closing of high-seas fisheries, rehabilitation of water quality, habitat loss caused by damming and channelling, and increased pressure from recreational fisheries. Even when these other factors have been accounted for, it is difficult to evaluate whether all hatchery programmes have actually increased net populations. To use these programmes more effectively, it is necessary to evaluate both their river- and species-specific benefits and compare hatchery programmes with other management tools, such as fishery controls and habitat rehabilitation. Future hatchery programmes should incorporate active, adaptive learning approaches to minimize the risks associated with artificial propagation and to promote sustainable salmon stocks.

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Population Viability Improves Following Termination of Coho Salmon Hatchery Releases

North American Journal of Fisheries Management ◽

10.1002/nafm.10029 ◽

2018 ◽

Vol 38 (1) ◽

pp. 39-55 ◽

Cited By ~ 3

Author(s):

Kim K. Jones ◽

Trevan J. Cornwell ◽

Daniel L. Bottom ◽

Staci Stein ◽

Kara J. Anlauf-Dunn

Keyword(s):

Coho Salmon ◽

Population Viability ◽

Salmon Hatchery

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An Errors-In-Variables Bias Model with an Application to Salmon Hatchery Data

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f90-164 ◽

1990 ◽

Vol 47 (7) ◽

pp. 1453-1467 ◽

Cited By ~ 10

Author(s):

J. T. Schnute ◽

T. J. Mulligan ◽

B. R. Kuhn

Keyword(s):

Oncorhynchus Tshawytscha ◽

Oncorhynchus Kisutch ◽

The Other ◽

Errors In Variables ◽

Bias Model ◽

Analytical Formulas ◽

Direct Counting ◽

Salmon Hatchery ◽

Ev Model ◽

Coded Wire Tags

This paper presents an errors-in-variables (EV) model for assessing differences between two measurements of the same phenomenon, where each measurement is subject to error. The model, equivalent to a classical EV model, specifically includes parameters associated with the relative bias between the two measurements. We derive a complete statistical theory for this errors-in-variables bias (EVB) model, including analytical formulas for confidence intervals that are exact when the error lies in one variable alone and approximate otherwise. The model is used to compare two methods of estimating the number of salmon that return to their hatchery of origin. One method involves direct counting, while the other is based on fish marked with coded wire tags (CWTs). We conclude that, for coho (Oncorhynchus kisutch) and chinook (Oncorhynchus tshawytscha) hatcheries in British Columbia, Canada, estimates from CWTs are, on average, 22% lower than comparable counting estimates.

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