Research cruise reveals increase in sardine juvenile biomass
PORTUGAL
Thursday, December 12, 2019, 02:40 (GMT + 9)
The Portuguese Institute of Sea and Atmosphere (IPMA) has announced the results of the oceanographic survey that it developed in September, together with the Spanish Institute of Oceanography (IEO), to estimate the biomass of sardine juveniles and anchovy with acoustic methods, and to perform an environmental characterization of the pelagic ecosystem on the western coast of the Iberian Peninsula.
Final estimates point to an increase in sardine juvenile abundance, from the 534 million fish estimated in 2018 to 5,452 million in 2019, more than the estimated 4,821 million used to assess the status of the stock in 2019.
In the IBERAS 2019 research cruise it was observed that the highest concentration of juveniles is on the northwest coast of Portugal, between Aveiro and Figueira da Foz, considered the main recruitment area for the southern sardine stock.
The estimated recruitment in the northwest coast by IBERAS is higher than the recruitments found in the research surveys carried out during the last decade, and slightly above the historical average recruitment observed in the northwest coast of the series of three autumn cruises.
The IBERAS research cruise seeks to determine a recruitment index that will be included in the southern sardine stock assessment model to assess the recruitment force corresponding to the year in which the stock status is estimated.
Currently, in the absence of a recruitment indicator, a geometric average of the last five years is assumed for the interim period and next year in the short-term forecasts. In the assessment of the status of the 2019 stock, a level of 4,821 million individuals was assumed, which is lower than what is now determined by acoustic means.
A preliminary analysis presented to the International Council for the Exploration of the Sea (ICES) in November 2019 indicates that autumn research cruises appear to be a good indicator of the strength of recruitment. Its inclusion in the current stock asessment model will be reviewed by ICES.
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In the IBERAS 2019 research cruise it was observed that the highest concentration of juveniles is on the northwest coast of Portugal, between Aveiro and Figueira da Foz, considered the main recruitment area for the southern sardine stock.
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