Rajidae

Explicatory Title:

Species composition of Family Rajidae in the Spanish landings from the Northwestern Iberian waters (ICES Divisions VIIIc y IXa)
Pepe Cebrian y SAP
Abstract:
Skates are aby-catch for the diferent fleets operating in the Northwestern Iberian waters (ICES Divisions VIIIc and IXa). In the landings of bottom otter trawlers skates mainly occur between 5 and 10% of the totalcatch.
Unfortunately, skates are usually recorded under general taxonomic groups in the Spanish fishery statistics, being identified only to family (Rajidae) or genus (Raja spp.).
Thismis-identification has been influenced in some extent related to the European management System, where a common TAC system for skates is applied. Nevertheless,TAC regulation(Council Regulation (EC) No43/2009), catches of certain skates species must be reported separately by Member State.
Since 2009, due to the implementation of the concurrent sampling methodology, as is required in the DataCollection Framework (DCF) regarding the Common Fisheries Policy (Dec. 2008/949/EC) ,the Spanish skates landings have been sampled by the Instituto Español de Oceanografia(IEO), in order to obtain monthlylength compositionsby species.
Up to ten species of Family Rajidae have been recorded in Northwestern Iberian Spanish landings: Blue skate (Dipturus batis), Longnosed skate (D. oxyrinchus), Sandy ray(Leucoraja circularis), Cuckoo ray (L. naevus), Blonde ray (Raja brachyura), Thornback ray (R. clavata), Smalleyed ray (R. microocellata), Brown ray (R. miraletus), Spotted ray (R. montagui), andUndulate ray (R. undulata)..

In this paper, results from sampling programme taken from September 2009 to September 2011 are used to estimate the skates’ species composition in the Spanish landingsfrom Northwestern Iberian waters. Furthermore, their respective length frequency distributions, as well as other parameters will be described.

Keyword:
Rajidae, Sampling, Landings, Northwestern...