Scientia Marina, Vol 67, No 3 (2003)

Trends of anchovy (Engraulis encrasilocus, L.) biomass in the northern and central Adriatic Sea


https://doi.org/10.3989/scimar.2003.67n3327

Alberto Santojanni
Istituto di Ricerche sulla Pesca Marittima (ISMAR - CNR), Italy

Enrico Arneri
Istituto di Ricerche sulla Pesca Marittima (ISMAR - CNR), Italy

Catherine Barry
Marine Resources Assessment Group (MRAG), United Kingdom

Andrea Belardinelli
Istituto di Ricerche sulla Pesca Marittima (ISMAR - CNR), Italy

Nando Cingolani
Istituto di Ricerche sulla Pesca Marittima (ISMAR - CNR), Italy

Gianfranco Giannetti
Istituto di Ricerche sulla Pesca Marittima (ISMAR - CNR), Italy

Geoff Kirkwood
Renewable Resources Assessment Group (RRAG), United Kingdom

Abstract


Anchovy (Engraulis encrasicolus, L.) is one of the most important commercial species of the northern and central Adriatic Sea. The mean annual catch of anchovy estimated by IRPEM for these areas, in the time interval 1975-1996, is equal to 25,000 tonnes. Estimates of anchovy stock biomass at sea in the time interval 1975-1996 were obtained using two population dynamics methods based on different data inputs: Virtual Population Analysis (VPA) and the DeLury model with recruitment index. VPA was carried out tuning the estimated fishing mortality rate at age by fitting on corresponding Catch Per Unit of fishing Effort (CPUE). Both VPA and the DeLury model yielded sensible results. The effect on the assessments due to the use of a different birth date and thus of split-year data was investigated. Biomass values as well as patterns over time so estimated were similar on the basis of both assessment methods and calendar year versus split-year data. In particular, the biomass in more recent years (around 100,000 tonnes) was lower than in the second half of the 1970s and first half of the 1980s (over 200,000 tonnes). The minimum value (lower than 50,000 tonnes) was always estimated in 1987, when a strong drop in the catch and crisis of the anchovy fishery took place. Though high values of both fishing effort and fishing mortality/exploitation rate were obtained for some years before 1987, very low levels of recruitment in 1986 and 1987 seem to be mainly responsible for the collapse of the stock.

Keywords


anchovy; Adriatic Sea; Virtual Population Analysis; Laurec-Shepherd tuning; DeLury model with recruitment index

Full Text:


PDF


Copyright (c) 2003 Consejo Superior de Investigaciones Científicas (CSIC)

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.


Contact us scimar@icm.csic.es

Technical support soporte.tecnico.revistas@csic.es