RIM18(5): Spawning Stock Biomass estimates of the Bay of Biscay anchovy (Engraulis encrasicolus, L.) in 2010 applying the Daily Egg Production Method

rim18_5Author / Editor: María Santos, Andrés Uriarte, Leire Ibaibarriaga (AZTI-Tecnalia)

Year: 2011

Content:  The research survey BIOMAN2010 for the application of the Daily Egg Production Method (DEPM) for the Bay of Biscay anchovy was conducted in May 2010, from the 5th to the 20th, covering the whole spawning area of the population. Total egg production was calculated as the product of the spawning area and the daily egg production rate, which was obtained from the exponential decay mortality model fitted as a Generalised Linear Model (GLM) to the egg daily cohorts. The adult parameters: sex ratio, batch fecundity and weight of mature females, were estimated from the adult samples obtained during the survey and the spawning frequency was calculated as the mean from the historical series. The spawning biomass estimate resulted in 42,979 t with a coefficient of variation of 15%, which supposes an increase of about 73% over the SSB estimate of 2009 produced in a similar way by the DEPM.

Contact: biblioteca@azti.es

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