A comparative assessment of the Black Sea anchovy stock using holistic production and analytical age structure models


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Akkuş G., Gücü A. C.

Acta Biologica Turcica, no.35(3), pp.1-12, 2022 (Peer-Reviewed Journal)

  • Publication Type: Article / Article
  • Publication Date: 2022
  • Journal Name: Acta Biologica Turcica
  • Page Numbers: pp.1-12
  • Middle East Technical University Affiliated: Yes

Abstract

The Black Sea anchovy (Engraulis encrasicolus) is economically and ecologically the most important

commercial fish species in the Black Sea. Therefore, a management plan targeting the maximum sustainable

yield has gained importance in recent years. The present study aims to provide a comprehensive assessment by

using only Turkish data to evaluate the status of the Black Sea anchovy stock and compare the different

approaches outcomes. For this, ASPIC (1968-2014) as a holistic production model and XSA (2005-2014) as

an age-structured model are used. ASPIC estimates that the Black Sea's carrying capacity (K) is 1.2 million

tons of anchovy, and to achieve the MSY of 244kton fish, 610kton (BMSY) fish must be present in the sea. It

is estimated B2015 is 399ktons; this shows, now, there are 35% fewer fish present in the sea. Hence, the Black

Sea anchovy is exposed to low overfishing. In XSA, the stock-recruitment relationship could not be established.

Therefore, the current status of anchovy stock is estimated by Patterson’s (1992) precautionary exploitation

rate of Etarget=0.4 as a reference point. Accordingly, the current exploitation rate is calculated as Ecurrent=0.5,

which is 25% higher than the Etarget. Hence, XSA results also suggest that the Black Sea anchovy is exposed

to low overfishing. This result and the comparable parameter of F of the two models show the concordance

and comparability of holistic (ASPIC) and analytic (XSA) models.