Preliminary results from the ECOCADIZ-RECLUTAS 2020-10 Spanish acoustic survey (02 – 21 October 2020)

The present working document summarises a part of the main results obtained during the ECOCADIZ-RECLUTAS 2020-10 Spanish (pelagic ecosystem-) acoustic survey. The survey was conducted by IEO between 02nd and 21st October 2020 in the Portuguese and Spanish shelf waters (20-200 m isobaths) off the Gulf of Cadiz (GoC) onboard the R/V Ramón Margalef. The survey’s main objective is the acoustic assessment of anchovy and sardine juveniles (age 0 fish) in the recruitment areas of the GoC. The 21 foreseen acoustic transects were sampled. A total of 22 valid fishing hauls were carried out for echo-trace ground-truthing purposes. This working document only provides abundance and biomass estimates for anchovy, sardine and chub mackerel, which are presented without age structure. The distribution of all the mid-sized and small pelagic fish species susceptible of being acoustically assessed is also shown from the mapping of their back-scattering energies. GoC anchovy acoustic estimates in autumn 2020, 36 070 t and 3197 million fish, showed a decrease in relation to the historical peak recorded the last year, but they were either close (abundance) or even higher (biomass) than the time-series average. As usual, the bulk of the population, including juveniles, was located in Spanish waters. GoC sardine experienced a huge increase in autumn 2020, rising up to its time-series maximum and yielding 208 400 t and 5451 million fish, with similar regional contributions to the population and with the juveniles being located in the Spanish coastal waters. Chub mackerel estimates were of 22 918 t and 295 million fish, representing a slight decrease compared with the last year, but still above the time-series average