Fishing research survey at the Bay of Biscay. (Photo: AZTI)
Juvenile anchovy biomass reaches historic maximum in Bay of Biscay
Friday, December 01, 2017, 00:50 (GMT + 9)
The biomass of juvenile anchovy in the waters of the Bay of Biscay registers a historical maximum, of about 725,000 tonnes, the highest level of the time series that began to be registered in 2003.
This estimate is one of the main findings of Juvena 2017 scientific survey, and was based on the analyzes carried out by AZTI research staff with the data obtained during 32 days, most of it in September, onboard the oceanographic vessels Emma Bardan and Ramon Margalef, belonging to the fleets of the General Secretariat of Fisheries and the IEO, respectively.
The scientists also determined that the average anchovy size is 6.5 centimeters long and that most of the biomass is located outside the continental shelf.
The estimated biomass, which is slightly higher than that of 2014 (724,000 tonnes), predicts a high recruitment for next year and confirms the good state of the resource after its recovery and following the collapse that led to its closure at the beginning of the 21st century.
These data confirm a favourable scenario for anchovy fishing in 2018, so it is expected that the total allowable catch (TACs) will be close to this year's (33,000 tonnes).
Juvena 2017 survey’s goal is to determine the abundance and spatial distribution of juvenile anchovies, study their status and analyze the environmental factors that may affect their survival, all aimed at predicting the amount of biomass that will reach adulthood in the year next. The abundance of juvenile anchovy is used as a recruitment index in the evaluation model of the anchovy management system.
In addition to assessing the abundance of juvenile anchovy, the AZTI survey collects data from the entire marine ecosystem to understand the processes that affect it. In particular, in recent years AZTI researchers have evaluated the spatial distribution of large marine predators in the Bay of Biscay. To this end, they have analyzed the distribution and abundance of birds and marine mammals, collecting information on the species present there, the number and behaviour of the specimens sighted during the trip.
With regards to marine mammals, eight different species have been observed, highlighting the abundance of the common dolphin, followed by the fin whale and the bottlenose dolphin.
In relation to seabirds, their distribution and abundance have been studied, with 33 different species being observed. The presence of the common gannet, followed by the great shearwater, the big skua and the dark shearwater has been highlighted.
Juvena juvenile anchovy survey is complemented by Bioman survey, also carried out by AZTI, which calculates the anchovy breeding biomass in spring in the Bay of Biscay by the method of daily egg production.
The final assessment of the stock status will be carried out by the International Council for the Exploration of the Sea (ICES). AZTI scientists will participate in this forum and their contributions will be taken into account for the final calculation of the anchovy stock and the TAC that the European Union will determine for the 2018 survey.