AZTI-Tecnalia and Spanish Oceanographic Institute launch trawl survey to identify population of young anchovy in the Bay of Biscay

AZTI-Tecnalia, the technological centre specialising in marine and food research, jointly with the Spanish Oceanographic Institute (IEO) have launched the JUVENA 2013 scientific trawl survey the fundamental aim of which is to identify the population and the spatial distribution of young anchovies in the Bay of Biscay, as well as the oceanographic processes involved in the repopulation of the stock of this fish species therein. In order to carry out the study, a group of experts from AZTI-Tecnalia and the IEO embarked from the Port of Gijón (Asturias) last Friday on board the oceanographic research vessel, Ramón Margalef, part of the IEO fleet. Subsequently, on Sunday 1 September, another team of researchers took to the sea from the same port on the Emma Bardán oceanographic research vessel, this belonging to the General Secretariat for the Sea.

The Basque technological centre has been undertaking this scientific trawl survey since 2003 and, since 2012, they have carried it out in conjunction with the Spanish Oceanographic Institute (IEO). The research will determine the abundance of the young anchovy population; i.e. of those eggs which were laid in spring and which will become fertile adults at one year of age in the spring of next year. The researchers will study, moreover, the state of their biological condition and analyse the environmental factors that affect their survival and the repopulation of the fishing grounds. The estimate of the young biomass will help to forecast the quantity of anchovies that will reach adult age over the next year. The results of the JUVENA survey are used to make recommendations to fisheries authorities about permitted anchovy catches.

The research – financed by the Department for Economic Development and Competitiveness of the Basque Government, the Spanish General Secretariat for the Sea and IEO – is to last for 35 days, over which period the two vessels will sail almost the whole of the Bay of Biscay. AZTI-Tecnalia will be responsible for the evaluation of the young anchovies while the IEO will deal with the ecological aspects related to the dynamics of stock repopulation. The scientists will calculate the population of the young anchovies through acoustic methods, using ultrasounds beamed into the water and then analysing their echoes in order to estimate the biomass in the zone under study. The scientists also have two other, additional, objectives: how to study the state of the biological condition and the behaviour of the young anchovies; as well as how to analyse the oceanographic conditions and the components of the pelagic ecosystem – that found in the uppermost layers of the sea -, from plankton to the upper layer communities of pelagic fish and the predators which feed off the anchovies (birds and marine mammals). Knowledge of this ecosystem is of great importance for understanding the process of development of the anchovy, from its larval stage to that of one year.

La JUVENA scientific trawl survey employs two vessels of small or medium size, as their lesser draught enable them to prospect in the most optimum conditions for studying the population of the young anchovies, and which usually occupy the first few metres from the water surface. Another reason for using two vessels is to cover a greater potential area in a short time, as the young anchovies, in this period, can inhabit either ocean waters out at sea or coastal waters.