Journal Article

Consequences of bias in age estimation on assessment of the northern stock of European hake (<i>Merluccius merluccius</i>) and on management advice

Michel Bertignac and Hélène de Pontual

in ICES Journal of Marine Science

Published on behalf of ICES/CIEM

Volume 64, issue 5, pages 981-988
Published in print July 2007 | ISSN: 1054-3139
Published online April 2007 | e-ISSN: 1095-9289 | DOI: http://dx.doi.org/10.1093/icesjms/fsm039
Consequences of bias in age estimation on assessment of the northern stock of European hake (Merluccius merluccius) and on management advice

More Like This

Show all results sharing these subjects:

  • Environmental Science
  • Marine and Estuarine Biology

GO

Show Summary Details

Preview

Bertignac, M., and de Pontual, H. 2007. Consequences of bias in age estimation on assessment of the northern stock of European hake (Merluccius merluccius) and on management advice. – ICES Journal of Marine Science, 64: 981–988.

The results of a pilot tagging study on hake (Merluccius merluccius), conducted in the northern part of the Bay of Biscay in 2002, indicate that growth rates for this stock may be currently underestimated because of biased estimates of age. The impact that such a bias may have on the stock dynamics and the trends of the key population parameters, recruitment, spawning-stock biomass (SSB), and mortality are investigated. Assuming new growth parameters, a new age–length key is derived and used to produce and catch-at-age data and abundance indices, which are then used to assess the stock. Bias in estimating age affects the absolute levels of fishing mortality and stock biomass estimates, and also impacts the trend in SSB. However, trends in fishing mortality and recruitment are comparable, and the stock status with respect to precautionary reference points is broadly the same. As expected, the simulation also shows that the stock may be more reactive to changes in fishing levels, which affect medium-term forecasts. Long-term sustainable yields may also be impacted.

Keywords: age estimation; European hake; growth; management; simulation; stock assessment; tagging

Journal Article.  4416 words.  Illustrated.

Subjects: Environmental Science ; Marine and Estuarine Biology

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.