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  • 1
    Publication Date: 2021-05-19
    Description: In this paper, the authors explore functional relationships between environmental fluctuations and some key parameters used in stock assessment such as recruitment and catchability. Yellowfin tuna (Thunnus albacares) is taken as an example but the concepts developed in this study could be widened to other tropical tunas. The French purse seine data-set is used to estimate a recruitment index from adjusted CPUE of age 0 fishes, and the effect of the environment on catchability is assessed using CPUE of age 3 fishes which provide the bulk of adult catches. The ACE algorithm is used to describe a non-linear relationship between the recruitment and the turbulence (wind speed cubed). There is a detrimental effect of an increasing turbulence on recruitment. The optimal transformation of this simple regression explains more than 25 % of the variance of recruitment. The analogy, with the fundamental triad and the optimal environmental window that explain the variability of small pelagic fish populations, is discussed. Regarding catchability, there is clearly a non-linear relationship between the CPUE age 3 and the depth of the isotherm 20°C (denoting the core of the thermocline), with a negative effect of deeper thermocline. These results are used to assess the potential effects of the El Niño-Southern Oscillation (ENSO) events on tuna stocks and their exploitation. The dynamics of ENSO in the Indian Ocean are described, and it appears that the latest event (1997-98) will remain classified in this ocean as extremely intense. The fishing pattern of purse seiners changed drastically: an abnormal easterly wind stress along the equator induced a reversal of the slope of the ocean (and consequently that of the thermocline. Rising of thermocline in the eastern basin generated increased catchability for purse seine gears. It is also suggested that ENSO would promote success of recruitment for tropical tunas. However, the consequence for the stock is not straightforward, as the response might be related to its level of exploitation.
    Description: Published
    Keywords: Recruitment ; Catchability ; El Nino phenomena ; Tuna fisheries ; Southern Oscillation ; Catch/effort ; Thunnus albacares ; ISW, Indian Ocean
    Repository Name: AquaDocs
    Type: Proceedings Paper
    Format: 1210815 bytes
    Format: application/pdf
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  • 2
    Publication Date: 2021-05-19
    Description: This paper aims to guide fisheries biologists in the use of current knowledge of the El Niño-Southern Oscillation (ENSO) phenomenon in order to address its impact on fisheries in the Indian Ocean. It is widely accepted that both the Indian and the Pacific Oceans are closely linked through the Indonesian Throughflow and the strong convective activity that occurs there. In order to tackle the ENSO phenomenon, it is therefore crucial to adopt a coupled Indian-Pacific Ocean approach. ENSO mechanisms in the Pacific are well known, but the role of the Indian Ocean in these mechanisms is not as clear. Due to the fact that air-sea interactions in the Indian Ocean are a new area of research, our knowledge is still not sufficient to have an overall view of the Indian-Pacific/ocean-atmosphere system. Nevertheless, climate monitoring is increasing in the Indian Ocean in order to enable its study. Hence parameters useful for taking the Indian-Pacific coupling into account are identified in this paper and their real-time monitoring, available on the internet or through National Meteorological Centres, is proposed for the purpose of fisheries biology studies. To make full use of the available data and to facilitate the interpretation of observations, the unique features of the Indian Ocean's climatology and oceanography and the monsoon system are first described in relation to the ENSO phenomenon. 'Research Group' , avenue du Jura 01210 Ferney-Voltaire France, Southampton Oceanographic Centre, Department of Oceanography.
    Description: Published
    Keywords: El Nino phenomena ; Tuna fisheries ; Fisheries biologists ; ISW, Indian Ocean
    Repository Name: AquaDocs
    Type: Proceedings Paper
    Format: 1529623 bytes
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 64 (1992), S. 442-467 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 66 (1994), S. 462-499 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Analytical chemistry 66 (1994), S. 3289-3296 
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 26 (1961), S. 4731-4733 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 34 (2003), S. 0 
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Effects of family differences on survival, length, weight, growth, and pyloric caeca number for juvenile rainbow trout Oncorhynchus mykiss were analyzed in binary associations of families (sib-groups), using a genetic variant with “golden” phenotype as a marker. In such an association, the performance of a family i mixed with family j depends on its own ability (P1), on the influence of the associated family (AJ), and on possible effects specific to the ij association. Experimental results showed that specific effects were negligible, and that the AJ influence was significant on body length and weight (after 3 mo of age), and opposite to the PJ value of the same family. Growth showed the same feature, but short of significance. The genetic marker caused some detrimental pleiotropic effects on length, weight, and growth, and some limited interactions with the familial factors studied. Results suggest that, when practicing selection, aquaculturists should prevent early size differences from becoming enhanced by competition, and should consider periodic size grading and multi-step selection. Results also suggest that family interactions should be accounted for when analyzing mixed-family genetic evaluation data.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 33 (2002), S. 0 
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Effects of egg size on weight and growth of juvenile rainbow trout Oncorhynchus mykiss were investigated within and between lots, using a genetic variant with “golden” phenotype as a marker. Analysis of between-lots variation corroborated earlier findings that egg weight influence on the juvenile body weight disappears after a few months of life. In contrast, within-lot effects of egg size were greater and persisted over a longer time. Egg size did not affect subsequent survival or specific growth of the juvenile trout. The genetic marker caused some detrimental pleiotropic effects on eyed egg yield and juvenile body weight, but not on juvenile survival or specific growth.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the World Aquaculture Society 36 (2005), S. 0 
    ISSN: 1749-7345
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Genetic and environmental components of variance of body length in juvenile brown trout Sabno trutta were estimated from the results of three experiments. The additive genetic variance increased in the first months posthatch, but was gradually overwhelmed by environmental and residual variances, so that heritability, after going through a maximum (about 0.45) at 3 mo, decreased later on. However, constancy of genetic factors was indicated by high genetic correlations (0.8-1.0) observed between successive measurements. Maternal effects were visible, but not statistically significant. There was no evidence of non-additive genetic variation. These results suggest that selection for precocious growth among separate families should be performed at the time when heritability is about maximum. Accounting for the importance of the within-lot variation (80-90% of the total variation), individual selection should be considered, as compared to more expensive methods.
    Type of Medium: Electronic Resource
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