Fish diversity is high in this ecoregion, reflecting its wide latitudinal dimension. The pelagic habitat is mainly dominated by sardine, anchovy, mackerel, horse mackerel, and blue whiting (Micromesistius poutassou). Some migratory species also appear in specific periods, such as tuna species (albacore [Thunnus alalunga] and bluefin [Thunnus thynnus], which feed upon smaller pelagic fish. Hake is the most abundant predator species in the demersal community. Anglerfish (Lophius budegassa, Lophius piscatorius), megrim (Lepidorhombus boscii, Lepidorhombus whiffiagonis), and sole (Solea solea) are more abundant in the northern part of the ecoregion. The limit of distribution for some cold-water species such as whiting (Merlangius merlangus) and pollack (Pollachius pollachius) is in the north of Portugal. Skates, sharks, and deep-sea fish occur over the continental slope and in the deeper parts of this ecoregion. Recruitment to the European eel (Anguilla anguilla) population has declined sharply in recent decades. For evaluated stocks, the spawning-stock biomass (SSB) is above reference points (Btrigger). Figure 9 displays the historical evolution of SSB relative to reference points by fish guild in the Bay of Biscay and the Iberian Coast ecoregion, and shows an increase in the SSB that has been observed since 2002.
Within this ecoregion the topographic diversity and the wide range of substrates result in many different habitats for cephalopods. The most abundant and commercially exploited species are long-finned squid (Loliginidae) and cuttlefish (Sepiidae). The abundance of short-finned squid (Ommastrephidae) increases westwards towards Galicia and decreases to the south of the Iberian coast. Short-finned squid are abundant and heavily exploited along the Iberian coast by a large artisanal fleet, with concomitant social relevance. There are indications of a decline in octopus biomass index in Galicia and an increase off western Portugal. Stocks of both long-finned squid and short-finned squid have declined in the southern Bay of Biscay.
Cuttlefish landings and population indices from the English Channel and Bay of Biscay have shown decreasing trends in recent years. Low biomass indices for Loligo forbesii were observed in the Bay of Biscay during 2016–2018 compared to 2013–2015. Other loliginids (L. vulgaris and Alloteuthis sp.) display an increasing trend in survey abundance, although landings are decreasing. The survey abundance for Illex coindetii has shown an increasing trend since 2015 in the Bay of Biscay but not in the Iberian Coast. The other ommastrephid species (Todarodes sagittatus and Todaropsis eblanae) have shown a decreasing trend both in surveys and landings. Survey abundance indices for octopus show wide annual fluctuations without a clear trend.
OSPAR-listed threatened and declining species in
the Bay of Biscay and the Iberian Coast ecoregion:
Threatened and declining habitats in the Bay of Biscay and the Iberian Coast ecoregion according to OSPAR:
Figure 9: Time-series of annual relative spawning‑stock biomass (SSB to MSY Btrigger ratio) by fisheries guild for benthic, demersal, crustaceans, and pelagic stocks. Table A1 in the Annex details which species belong to each fish category.