Hotelling's T2 to Identify the Origin of Atlantic Salmon (Salmo salar) in a Mixed-Stock Fishery

1985 ◽  
Vol 42 (2) ◽  
pp. 250-255 ◽  
Author(s):  
D. G. Reddin ◽  
R. K. Misra
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Misclassification Rate ◽  
Commercial Fishery ◽  
Commercial Sample ◽  
New Approach ◽  
Atlantic Salmon Salmo Salar ◽  
Leave One Out ◽  
Mixed Stock ◽  
River Size

We used a new approach based on measurements of four scale characters, for identifying Atlantic salmon (Salmo salar) caught in the commercial fishery at St. Ann's Harbour, Nova Scotia, and that were returning to North River. Utilizing Hotelling's T2, we compared the vector of observations of each member of the commercial sample (size = 29) with the vector of means of the sample from the angling fishery on North River (size = 48). Misclassification rate was estimated by the "leave-one-out" technique. The variables chosen for analysis were the measurements of the longest oral radii between each of the first three river and first sea annuli. The analysis indicated that 79–88% of the individuals in the commercial sample could have been migrating to North River. This technique is proposed for cases in which the requirement to have samples from all contributing stocks for discriminant analysis is not possible.

Atlantic Salmon (Salmo salar) Stocks and Management Implications in the Canadian Atlantic Provinces and New England, USA

1981 ◽  
Vol 38 (12) ◽  
pp. 1612-1625 ◽  
Author(s):  
Richard L. Saunders
Keyword(s):  
Atlantic Salmon ◽  
New England ◽  
Salmo Salar ◽  
Environmental Influence ◽  
Function Analysis ◽  
Significant Degree ◽  
Growth Patterns ◽  
Point Of View ◽  
Atlantic Salmon Salmo Salar ◽  
Mixed Stock

This paper discusses the diversity of Atlantic salmon (Salmo salar) expressed as anatomical, physiological, and behavioral differences among stocks in the Atlantic Provinces of Canada and New England, USA. Evidence is reviewed for environmental and genetic influence on a number of stock-specific traits. Unique qualities of particular stocks are described. The loss of salmon from much of its former range is documented and discussed in relation to stock characteristics important in rehabilitation efforts. The mixed stock fisheries in Greenland and Newfoundland are considered from the point of view of interception. It is concluded that identification and management of specific stocks in the Greenland fishery are impracticable at present but that identification of North American components, using discriminant function analysis of scale growth patterns and smolt tagging, should be continued. In Newfoundland knowledge gained from tagging studies allows a significant degree of management of stocks from mainland Canada together with those from Newfoundland and Labrador. Since it is impracticable now to manage the fisheries off Greenland and Newfoundland and off the major Canadian Maritimes salmon-producing rivers—the Miramichi, Restigouche, and Saint John—in strict recognition of stocks, it is suggested that it may be possible to characterize an assemblage of like stocks from given areas and to identify and manage for these in large mixed-stock fisheries. Possible impacts of hatchery plantings are discussed in relation to prospects of success and effects on native stocks. It is concluded that we have the biological basis for evaluating likelihood of success and degree of danger to native stocks from extensive plantings of hatchery-reared juvenile salmon and that such evaluation should be conducted when embarking on projects involving use of hatchery-reared fish as part of a major salmon enhancement program in Atlantic Canada.Key words: genetics, environmental influence, rehabilitation, enhancement, interception, hatcheries, aquaculture

scholarly journals Provision of catch advice taking account of non-stationarity in productivity of Atlantic salmon (Salmo salar L.) in the Northwest Atlantic

2005 ◽  
Vol 62 (1) ◽  
pp. 131-143 ◽  
Author(s):  
G. Chaput ◽  
C.M. Legault ◽  
D.G. Reddin ◽  
F. Caron ◽  
P.G. Amiro
Keyword(s):  
Population Dynamics ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Model Prediction ◽  
Northwest Atlantic ◽  
Atlantic Salmon Salmo Salar ◽  
Parsimonious Models ◽  
Rate Of Decline ◽  
Management Advice ◽  
Mixed Stock

Abstract The paper presents the data, the models, and the approach for the provision of management advice for a high seas mixed stock fishery on Atlantic salmon (Salmo salar L.). The approach incorporates observation errors, model uncertainty, and considers a possible shift in the productivity of Atlantic salmon. The risk analysis framework further incorporates uncertainty in the fishery harvest characteristics and presents the catch advice as probabilities of meeting or exceeding the conservation objectives relative to catch options. There is very strong evidence from the analyses that there has been a phase shift in productivity of Atlantic salmon of North American origin in the Northwest Atlantic. The change in productivity likely resulted from a change in marine survival which occurred in the early 1990s and has persisted to date. When the uncertainties in the input data are considered, the most parsimonious models suggest that there has been a shift in absolute abundance independent of variations in the spawner index contributing to the recruitment. There continues to be a large amount of uncertainty in the measures of abundance and population dynamics of Atlantic salmon. Uncertainty in the understanding of population dynamics does not necessarily equate to uncertainty in management advice. If model results suggest that spawning objectives are unattainable even when harvest rates are zero, then any harvest level will either accelerate the rate of decline if the model prediction is correct or diminish the probability of recovery if the model prediction is wrong.

Spatiotemporal dynamics of the Atlantic salmon (Salmo salar) Greenland fishery inferred from mixed-stock analysis

2009 ◽  
Vol 66 (12) ◽  
pp. 2040-2051 ◽  
Author(s):  
Marika Gauthier-Ouellet ◽  
Mélanie Dionne ◽  
François Caron ◽  
Tim L. King ◽  
Louis Bernatchez
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Time Course ◽  
Fish Stocks ◽  
Atlantic Salmon Salmo Salar ◽  
The North ◽  
Different Origins ◽  
Mixed Stock ◽  
Mortality Estimates

Mixed-stock fisheries refer to the exploitation of admixed fish stocks coming from different origins. We identified the North American origin of 2835 Atlantic salmon ( Salmo salar ) in the Greenland mixed-stock fishery during 11 years (1995–2006) at three localities using 13 microsatellites. The study included 52 baseline populations representing nine genetically distinct regional groups. The contribution of each group ranged from <1% (Maine) to 40% (Southern Québec). Decreasing temporal contributions were observed for Southern Québec (–22.0%) and New Brunswick (–17.4%), whereas an increasing contribution for Labrador (+14.9%) was observed during the time course of the study. The estimated regional contribution to the Greenland fishery was significantly correlated to the number of multi-sea-winter salmon regionally produced in 2002 (r = 0.79) and 2004 (r = 0.92). No difference in contribution was found between the three Greenland sampling localities. Ungava and Southern Québec regions showed the highest mortality estimates caused by the fishery, ranging from 12.10% to 18.08%, for both years tested. No regional group was overrepresented in landings compared with their respective productivity. Yet, management precautions should still be taken as the fishery strongly selects large females, which could have evolutionary impacts on populations over the long term.

Distinguishing between resident and migrating Atlantic salmon (Salmo salar) stocks by genetic stock composition analysis

1995 ◽  
Vol 52 (4) ◽  
pp. 665-674 ◽  
Author(s):  
Marja-Liisa Koljonen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Composition Analysis ◽  
The Baltic Sea ◽  
Genetic Stock ◽  
Atlantic Salmon Salmo Salar ◽  
Genetic Stock Identification ◽  
The Baltic ◽  
Catch Composition ◽  
Mixed Stock

The possibility of using the genetic stock identification (GSI) method to distinguish between individual Atlantic salmon (Salmo salar) stocks and stock groups in Finnish catches was studied. In the Baltic Sea, the Atlantic salmon is a target of a mixed-stock fishery, and information about stock composition would be valuable for the management of the species. The salmon catches on the Finnish west coast consist of two seasonally variable components: a group of northern stocks migrating through the area to the Baltic main basin and the resident Neva salmon. The migratory component includes two endangered wild stocks (Tornionjoki and Simojoki). The allele frequency differences at four polymorphic loci among the stocks allowed reliable catch composition estimates to be made of the migratory and resident components; one stock (Oulujoki) from the northern group could also be identified with reasonable accuracy. Northern migrating stocks accounted for over half the catches at the time of this study. The estimate of natural (nonhatchery) stocks was very low (3% in total).

scholarly journals Managing Atlantic salmon (Salmo salar L.) in the mixed stock environment: challenges and considerations

2004 ◽  
Vol 61 (8) ◽  
pp. 1344-1358 ◽  
Author(s):  
W.W. Crozier ◽  
P-J. Schön ◽  
G. Chaput ◽  
E.C.E. Potter ◽  
N.Ó Maoiléidigh ◽  
...  
Keyword(s):  
Population Structure ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Atlantic Salmon Salmo Salar ◽  
Mixed Stock ◽  
Made In

Abstract Atlantic salmon, as a result of their population structure and behaviour, are potentially subject to a complex array of fisheries, ranging from those within rivers harvesting single stocks, to distant-water mixed stock fisheries that harvest fish from different countries, stock complexes, and continents. In addition, estuarine and in-river fisheries may catch fish from more than one stock or stock component, where these are present. One of the main challenges in managing salmon across this range of fisheries is to account for the differing status of stocks with respect to safe biological limits, noting that stocks of differing productivity may require different harvest strategies. Also, the existence of sequential harvest in different fisheries provides unique challenges, because decisions in an individual fishery cannot be made in isolation of the impacts of other fisheries on those stocks. We illustrate the uncertainties and complexities involved in managing mixed stocks of salmon, whether in home-waters or in distant-water fisheries, and examples are given to illustrate how science and management are, or should be, developing to face these challenges.

Analysis of Growth of Atlantic Salmon (Salmo salar) in a Small Newfoundland River

1978 ◽  
Vol 35 (1) ◽  
pp. 60-68 ◽  
Author(s):  
E. M. P. Chadwick ◽  
T. R. Porter ◽  
P. Downton
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Survival Rates ◽  
River System ◽  
First Year ◽  
Commercial Fishery ◽  
Atlantic Salmon Salmo Salar ◽  
Dependent Relationship ◽  
Survival Density ◽  
Sea Survival

Growth and sea survival rates decreased with increasing smolt age, with survival being 12, 6, and 3% for 3+, 4+, and 5+ smolt, respectively. All spawning fish were grilse, which suggests that older smolt became large salmon and were thus more vulnerable to the commercial fishery. A density-dependent relationship was observed for 3+ smolt in their 1st yr of growth, but not for older smolt; younger smolt probably spend their juvenile life in a more productive but space-limiting part of the river. Variation between river-system environments may be responsible for the opposing results of studies on Atlantic salmon (Salmo salar) life history. Key words: Salmo salar, growth, sea survival, density dependence, first-year growth, age at smoltification

No indications of Atlantic salmon (Salmo salar) shoaling with kin in the Baltic Sea

2008 ◽  
Vol 65 (8) ◽  
pp. 1738-1748 ◽  
Author(s):  
Stefan Palm ◽  
Johan Dannewitz ◽  
Torbjörn Järvi ◽  
Marja-Liisa Koljonen ◽  
Tore Prestegaard ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Baltic Sea ◽  
Salmo Salar ◽  
Genetic Relatedness ◽  
The Baltic Sea ◽  
Atlantic Salmon Salmo Salar ◽  
Related Individuals ◽  
The Baltic ◽  
Mixed Stock ◽  
Mixed Stock Analyses

Several studies have shown that fish shoals may consist of closely related individuals. It has been found, for example, that released out-migrating salmon smolts tend to aggregate with kin, including when sibling groups have been reared separately. We used genetic microsatellite markers to test whether “shoals” of adult Atlantic salmon ( Salmo salar ) during the marine phase (i.e., aggregations of fish caught in drift nets at offshore feeding areas in the Baltic Sea) consisted of closely related individuals (full-siblings, half-siblings). We found no evidence of kin cohesiveness related to shoals, however. Despite a weak overall tendency for individuals assigned to the same population (river or stock) to occur together, estimates of genetic relatedness in combination with consistent heterozygote deficiencies, and results from mixed-stock analyses and assignment tests collectively indicated that shoals consisted of unrelated fish from multiple populations.

scholarly journals Estimating and forecasting pre-fishery abundance of Atlantic salmon (Salmo salar L.) in the Northeast Atlantic for the management of mixed-stock fisheries

2004 ◽  
Vol 61 (8) ◽  
pp. 1359-1369 ◽  
Author(s):  
E.C.E. Potter ◽  
W.W. Crozier ◽  
P-J. Schön ◽  
M.D. Nicholson ◽  
D.L. Maxwell ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Statistical Significance ◽  
Geographical Area ◽  
Environmental Data ◽  
Environmental Indices ◽  
Northeast Atlantic ◽  
Atlantic Salmon Salmo Salar ◽  
Mixed Stock ◽  
Reconstruction Model

Abstract Most exploitation of Atlantic salmon (Salmo salar) is restricted to “homewater fisheries”, which operate close to or within the rivers of origin of the stocks, but two “distant-water fisheries” are permitted to operate off the west coast of Greenland and in the Norwegian Sea, and take salmon from a large number of rivers over a wide geographical area. Providing robust quantitative catch advice for these mixed-stock fisheries depends upon the ability to forecast stock abundance for about 2000 salmon river-stocks around the North Atlantic, more than 1500 of which are in Europe. A “run-reconstruction” model is presented for estimating the historic pre-fishery abundance (PFA) of salmon for countries or regions around the Northeast Atlantic, based upon catch data and estimates of non-reporting rates and exploitation rates. These estimates are then used to develop predictive models of PFA on the basis of estimates of the egg deposition, derived from the run-reconstruction model and various environmental data. Although the selected environmental indices correlated with the PFA of both southern and northern European stock complexes, the main statistical significance in the forecast models was provided by temporal trends in the PFA. Clearly, such a model is only tenable in the short term, and will be poor at predicting a major change in stock status. Alternative approaches, based upon juvenile production indices and including Bayesian techniques, are therefore being considered.

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