Search

The Spanish acoustic-trawl times PELACUS 0315 was carried out on board R/V Miguel Oliver from 14th March to 14th April, covering the north Spanish waters (Atlantic and Bay of Biscay) from the coast to the 1000 m isobath on a systematic grid with tracks 8 nmi apart and equally spaced. Acoustic , fishing stations, fish egg counting, microplastic, and apical predators observations were done during daytime whilst the oceanographic characterisation was done during night time. A total of 3979 nautical miles were steamed, 1190 corresponding to the survey track. Besides, 66 fishing stations were performed. PELACUS 0315 was characterised by a relative high strength of NE winds which led to change the survey sampling schedule. The area is typically covered continuously from the Spanish/Portuguese border to the French/Spanish one, but due to the wind the NW corner was steamed from the north-eastern part to the south-western one and also in the Cantabrian Sea, the inner part (i.e. Euskadi) was covered westward. Besides, this weather condition, together with the change in the strategy, would have been affected the mackerel fish distribution and abundance estimates: this was the first time in the time series that adult mackerel occurred in high quantities in IXaN while VIIIc-West was almost empty. Nevertheless, as compared with the biomass assessed in 2014 when the weather conditions were better and the therefore the stability would have increased the mackerel availability either for a change in the behaviour (i.e. spatial pattern distribution) or for an increase in the food availability, the estimated biomass in 2015 was lower. On the other hand, the increase in horse mackerel observed in 2014 was corroborated this year. In the case of anchovy, although during 2014 an important amount of new juveniles (young of the year) were detected during the JUVENA survey undertook in September in the Cantabrian waters, the anchovy distribution found at PELACUS was scarce in this area. During PELACUS 0315 blue whiting has been observed performing nictimeral migration towards the surface. This is the first time this movement has been recorded and described.