Venus clam | Cephalopods | Shrimps |
Small pelagic fish | European hake | Large pelagic fish |
Key species of the Cadiz region |
Venus clam
In the Huelvas sector, the molluscan fishery is a critical resource in local economies. The key species is the striped venus clam (Chamalea gallina), well adapted to mud-sandy sediments from 0 - 20 m. The venus clam has been intensively exploited in the last decade and it is currently under a specific conservation and management program.
Cephalopods
Cuttlefish and octopus are key species in the region. Octopus is a largely fluctuating species without a clear explanation about those fluctuations. Cuttlefish shows more stable populations, living in sandy habitats of the continental shelf, with local feeding migrations and a reproductive migration to shallow waters especially during spring and summer. Captured by bottown-trawl and gillnet fleets, the cuttlefishis considered an intensively exploited species.
Shrimps
The key species among the crustaceans are deep-water rose shrimp (Parapenaeus longirotris) and triple-grooved shrimp (Melicertus kerathurus). Both species are necto-benthic, however, while the deep-water rose shrimp lives in habitats at 90-250 m water depth, the triple-grooved shrimp lives in autumn and winter between 40-100 m waterdepth, but move into shallow waters (< 10 m) and river mouths for reproduction during spring and summer. Their habitat preferences are sandy or sandy-mud bottoms. The larval and postlarval stages of the triple-gooved shrimp prefer low-salinity environments (river mouths) before migrating to deeper shelf waters in late autumn. Both species can be considered as intensively exploited species.
Small pelagic fish
The key fish in Huelvas fisheries are small pelagic species - sardine (pilchard Sardina pilchardus, round sardinella Sardinella aurita) and anchovy (Engraulis encrasicolus). The two sardine species are seasonal spawners; the pilchard reproduces in winter, while the round sardinella spawns in warm shelf waters during summer. Anchovy spawns late spring-summer but in rivers mouths, mainly in the mouth of the Guadalquivir River in the warm waters created within the cyclonic cell described in the overview of the ecosystems - sections environment and ecology. In recent years, the pilchard population is showing large fluctuations closely related to weakening of the Portuguese upwelling. Sardine and anchovy can be considered intensively exploited species, but they are also key species for the trophodynamic functioning of the marine ecosystems in the Huelva region.
European hake
The top predator fish in the Huelva fishery region is the European hake (Merluccius merluccius) which supports a highly valuable fishery, but which can be considered a highly/extremely exploited species.
Large pelagic fish
The Huelva littoral ecosystems are in the northward migration pathways of juvenile bluefin tuna (Thunnus thynnus) spawned in the Mediterranean Sea. Other ecologically relevant species migrating off the Huelva coast during late spring and summer are the skipjack tuna (Katsuwonus pelamis) and the frigate mackerel (Auxis rochei).
Key species of the Cadiz region
The Cadiz region is characterised by different key species to the Huelva region. There is not a commercial shellfish activity in the Cadiz region, except in the west, where a small fleet fishes on the Huelva shelf. Similarly, shrimp are found close to the mouth of the Guadalquivir River in the limit between Huelva and Cadiz.
The most important and frequently exploited species on the Cadiz coast are species associated with rocky substrata (due to geomorphological features and the proximity of the region to the Gibraltar Strait), and large and small pelagic fish species. Key species of mollusc include octopus and cuttlefish associated with rocky bottom substrates which they use for shelter.
The key fish species in Cádizs fisheries are, as in the Huelva region, a wide spread of pelagic species including anchovy, atlantic mackerel, sardine, and bluefin tuna. Other predator fish species in the area include shade-fish (Argyrosomus regius), which appears in summer along the extent of the Gulf of Cádiz. The bluefin tuna undertakes important migrations to and from the warm waters of the Mediterranean used for spawning, through the Strait of Gibraltar, and has been caught by ancestral artisanal methods (end trap-netting) in spring and autunm.
