A first attempt of acoustically assessing the shallow waters (<20 m depth) off the Gulf of Cadiz (ICES Subdivision IXa South): the ECOCÁDIZ-COSTA 0709 Spanish Survey (July 2009).

The present working document summarises the main results from one IEO’s coastal (50 – 7 m depth) survey (ECOCÁDIZ-COSTA 0709) complementary and almost synchronous (2nd-9thJuly 2009, R/VFrancisco de Paula Navarro) to the Spanish “standard” acoustic (pelagic ecosystem-) survey (ECOCÁDIZ 0609; 27thJune-6th July 2009; Portuguese and Spanish shelf waters off the Gulf of Cadiz: 20-200 m isobaths; R/V Cornide de Saavedra). Unfortunately, the impossibility of fishing in waters deeper than 25 m depth with an appropiate gear resulted in a relatively high percentage (51.5%) of Not Identified NASCs in relation to the total sampled back-scattering energy attributed to fish, although these energies were mainly concentrated in the deepest ESDUs previously sampled and assessed by the conventional survey. Acoustic energies in the coastal survey were not very high in the shallower waters, which is reflected in the contribution to the total energy by the most coastal species.