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Increasing biological knowledge for a better management of the Eastern Baltic Sea cod

Mion, Monica (2018). Increasing biological knowledge for a better management of the Eastern Baltic Sea cod. Lysekil: (NL, NJ) > Department of Aquatic Resources, Sveriges lantbruksuniversitet. Aqua introductory research essay ; 2018:3

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Stock assessment is the synthesis of information on life history, fishery monitoring, and resource surveys. It is a critical management tool for monitoring the abundance of commercial fish populations, as well as for predicting the consequences of policy decisions. However, without the key biological reference parameters, e.g., growth rate and age, the estimation of spawning stock biomass and fishing mortality rate is unpredictable. During the past two decades, a number of changes in biology and ecological conditions has affected the Eastern Baltic cod stock, raising concerns among fisheries scientists and managers. Deteriorated quality of key biological parameters for stock assessment, such as true age, growth rates, and reproductive traits, in combination with changes in environmental and ecological conditions, has led the failure of the analytical stock assessment in 2014, leaving the present stock status unclear. Currently, it is unknown whether the drop in mean size and the disappearance of large individuals is due to a decrease in growth rates or by increased natural mortality. Therefore, whether the stock has suffered a decrease in productivity or an increase in mortality (fishing pressure or other natural causes) is an open dilemma, with large implication for fisheries management.  During my PhD, I will make use of results from historical tagging experiments, as well as new international tagging program to provide the necessary information on growth and mortality of Eastern Baltic cod to aid solving the issues with stock assessment. In addition, I will investigate the effects of the changes in growth and condition on cod reproductive potential. Finally, I will try to integrate all the gained biological knowledge (growth, mortality and reproductive potential) in new assessment models for a better management of the Baltic Sea cod.

Authors/Creators:Mion, Monica
Title:Increasing biological knowledge for a better management of the Eastern Baltic Sea cod
Series Name/Journal:Aqua introductory research essay
Year of publishing :2018
Number of Pages:35
Place of Publication:Lysekil
Publisher:Department of Aquatic Resources, Swedish University of Agricultural Sciences
ISBN for electronic version:978-91-576-9591-8
Publication Type:Report
Article category:Other scientific
Full Text Status:Public
Agris subject categories.:M Aquatic sciences and fisheries > M01 Fisheries and aquaculture - General aspects
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Fish and Aquacultural Science
Keywords:Eastern Baltic cod (Gadus morhua), tagging, life history, growth, fishing mortality, natural mortality, potential fecundity, stock assessment
Permanent URL:
Alternative URL:https://www.slu.se/globalassets/ew/org/inst/aqua/externwebb/sidan-publikationer/aqua-introductory-research-essay/aire_2018_3.pdf
ID Code:15905
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Department of Aquatic Resources
Deposited By: SLUpub Connector
Deposited On:11 Feb 2019 11:20
Metadata Last Modified:20 Aug 2020 00:11

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