Portuguese EEZ - Key Species
Sardine (Sardina pilchardus)
Sardine distribution in the North-East Atlantic covers a wide area, ranging from southern Mauritania to the northern part of the North Sea. Targetted by the purse seine fishery, sardine is the most abundant small pelagic species in Portuguese waters and also the most important species in terms of numbers caught. Sardine recruitment success has been linked to environmental conditions, thus sardine captures fluctuate interannually. For example landings in the northern Portuguese waters sharply decrease in 1998-2000, but have increased slowly but continuously since, while landings in the central waters have remained relatively stable, with some fluctuations and landings in the Algarve having decreased to a level equivalent to a third of the values in the middle 90s (ICES 2006).
Anchovy (Engraulis encrasicolus)
Anchovy is another small pelagic species, whose recruitment success is strongly driven by the environment. The fishery depends largely on the incoming year class and there are large inter-annual fluctuations in the spawning stock. Thus, the state of the anchovy stock can change quickly and management has to be carried out accordingly. Although some anchovy is landed in Portugal, most is landed in Spain, in the Gulf of Cadiz (more than 80% of total landings in ICES division IXa). Anchovies are caught by the purse seine fleets and the artisanal fleets.
Horse mackerel (Trachurus trachurus)
Horse mackerel are caught by both the trawl and purse seine fisheries, although the purse seine fishery has the highest catches (95%). Previously most of the catch was used for meal and oil while most is for human consumption. Most horse mackerel is caught in the second half of the year. Horse mackerel have a very long spawning season, extending from September to June. The full length range of the species is of commercial interest in Iberia, so discards are likely to be few. Spawner stock biomass (SSB) has declined over recent years. This decline is confounded by the fact that new trawls have been developed, especially designed for horse mackerel, which has led to an increase in catches in sub-area IXa North.
Blue whiting (Micromesistius poutassou)
Blue whiting is a pelagic gadoid widely distributed in the eastern part of the North Atlantic. It occurs in large schools at depths ranging between 300 and 600 m, between the Barents Sea and the Strait of Gibraltar. Peak spawning takes place in February and March, along the shelf edge and banks west of the British Isles. Juveniles are abundant in many areas, with the main nursery area believed to be the Norwegian Sea. Blue whiting is an important forage species in Portuguese waters. Blue whiting is not a target species in the Portuguese fishery, but some is caught by the trawl fishery.
Hake (Merluccius merluccius)
European hake is found from Norway (61ºN) to the coast of Mauritania (21ºN). It became an important fishing resource mainly after the decline of the cod fishery in the 1950s and the 1960s (Alheit and Pritcher, 1995). Hake is caught by the Portuguese fleet in the trawl and artisanal mixed fisheries with other fish species and crustaceans.
Southern hake spawns mainly from December to June, with a peak between February and March, and the adults predominantly concentrate in canyons and on the rocky bottoms of the shelf break area (Alcázar et al., 1983; Pérez and Pereiro, 1985; Piñeiro and Sainza, 2003). Hake recruitment may lead to well-defined patches of juveniles, found in localized areas over the continental shelf (Sánchez and Gil, 1999). These concentrations vary in density according to the strength of the year-class, although they remain generally stable in size and spatial location. Hake recruitment is influenced by the environment, and is less successful in years in which environmental conditions are extreme (Sanchez et al., 2003). In Portuguese continental waters, the abundance of small individuals is higher between autumn and early spring. In the southwestern area, fish are mainly concentrated at 200-300 m depths, while in the south they are mainly distributed in coastal waters. In the north of Portugal, recruits are more abundant between 100 and 200 m water depths (Cardador, 1995). These different depth-area associations may be related to the feeding habits of the recruits, since the zooplankton biomass is relatively higher in those areas in which the smaller fish are found (Cunha, 1993).
Hake is an important predator in this ecosystem. Small hake (> 20 cm) consume decapod prawns and larger hake (< 30 cm) prey on fish including blue whiting, sardine and snipefish. Cannibalism is relatively rare, probably due to the spatial distribution of the different size groups.
Megrims (Lepidorhombus boscii and L. whiffiagonis)
There are two species of megrims in Portuguese waters, megrim (L. whiffiagonis) and four-spot megrim (L. boscii). Both species are found in shallow waters along the coast but disappear at the mouths of the major rivers, probably due to continental run-off which modifies the sediment composition of the grounds where megrim feed, and creates grounds more appropriate for other flatfish that are adapted to estuarine conditions (Sánchez et al., 2001). Megrim's dependence on sediment is probably related both to the distribution of suitable prey and to the fact that flatfish bury into the sediments. There is a certain bathymetric segregation between the two species. L. boscii has a preferential depth range of 100 to 450 m and L. whiffiagonis of 50 to 300 m (Sanchez et al., 1998). Both species show a gradual expansion in their bathymetric distribution throughout their lifetimes, with larger individuals tending to occupy shallower waters than juveniles.
Juvenile megrim feed mostly on detritivorous crustaceans found on the deep-lying muddy bottoms. Adult L. boscii feed mainly on crustaceans inhabiting muddy surfaces (Rodriguez-Marín and Olaso, 1993; Rodriguez-Marín, 2002) while L. whiffiagonis are more ichthyophagous (Rodriguez-Marín, 2002). The spawning period of these species is short. Mature males can be found from November to March and mature females from December to March, but spawning peaks in March. In southern areas, megrim spawn from January to April.
Both species are taken as by-catch in the mixed bottom trawl fisheries, and also caught in small quantities by the artisanal fleet. Management of megrim is both by TAC and technical measures.
Anglerfish (Lophius spp.)
Two species of anglerfish, Lophius piscatorius and L. budegassa, are found in Portuguese waters. Both species are caught in mixed bottom trawl fisheries and in artisanal fisheries using mainly fixed nets. The two species are usually landed together and are recorded together in the port statistics. The two species are managed under a common TAC. There is no minimal landing size for anglerfish but an EU Council Regulation (2406/96) laying down common marketing standards for certain fishery products fixes a minimum weight of 500 g for anglerfish.
L. piscatorius is a North Eastern Atlantic species, with a distribution area from Norway (Barents Sea) to the Straits of Gibraltar (including the Mediterranean and the Black Sea). It is a slow growing species, which matures late. Age of first maturity has been estimated as about 7 years for males and higher for females (Duarte et al., 2001). Due to their reproductive strategy (extruded strings of eggs leading to spatially restricted juveniles); their slow growth and late maturation, the population dynamics of this species may be highly sensitive to external biological/ecosystem factors.
Rays (Raja brachyura, Raja clavata, R. montagui, and R. miraletus)
Skates and rays are landed by several Portuguese fleets, but mainly as by-catch of the artisanal segment of the commercial fishing fleet, and total annual landings are around 1500 tons. Landed specimens are not differentiated to species level, however, during a pilot study into the species composition of landings, a total of eight species were identified. Raja brachyura and Raja clavata were found to be the most common.
Blackmouth catshark and small spotted dogfish (Scyliorhinus canicula)
These species are found in the eastern North Atlantic from Norway to Senegal. They are very common in Portuguese waters, especially in the southwest. Dogfish are generally found at depths from 200-400 m, while catsharks are abundant between 600-800 m .
Both these species are captured by a number of gears including longlines, trawls and trammel nets, in particular as bycatch of either the black-scabbard fishery or the mixed fish trawl fishery . Elasmobranch landings have decreased in Portugal in recent years. In a recent study in the semi-pelagic longline fishery, seven elasmobranch species were caught, representing 33.4% of the total fish catch. Of these, Galeus melastomus represented 63.3% of all elasmobrnachs and Scyliorhinus canicula, 14.2%. Most elasmobranchs were discarded (68.3% in total), while in the trammel net fishery, sixteen elasmobranch species represented only 4.3% of the total fish catch, the most important species being Raja undulata (43.6%) and S. canicula (10.2%). The majority of elasmobranchs caught in trammel nets were of commercial value, and only 5.4% were discarded (Coelho et al. 2005).