English Channel (Eastern) - Key Species
King scallop (Pecten maximus)
The king scallop is a suspension feeder living preferentially on gravely, muddy-sandy and shelly bottoms. This hermaphrodite animal spawns several times per year. The larvae, pelagic for 30 days before attachment to the substrate, ensure some mixing between the different stocks. A very valuable species, the king scallop is caught with dredges and represent the commercially most valuable species for several French ports. The landings are seasonal due to the fishing restrictions.
Common sole (Solea solea)
Adult sole live on fine sand and muddy substrates and feed on annelid worms, small molluscs and crustaceans. Sole are active, especially at night, and bury themselves more or less completely during the day. After 5 to 11 days, pelagic eggs hatch into pelagic larvae that will metamorphose into benthic fry after one to two weeks. Juveniles spend the first two or three years in coastal nurseries, before later moving to deeper waters. Economically important, the Eastern Channel stock of sole is considered to be separated from the North Sea stock. In the English Channel, stock health indicators, including spawning biomass, remain within safe biological limits.
Squid (Loligo vulgaris and Loligo forbesi)
Found in waters of about 50 m in depth in the English Channel, squid can hunt prey through the water column. They feed mainly on small fish, crustaceans, polychaetes, shrimps and cephalopods, and cannibalism is common in these species. Females lay a few dozen to a hundred eggs in a gelatinous envelopes, which are fixed to hard substrates. On hatching, young squid are relatively large (7-8 mm) and subsequent growth is rapid. Because of its short lifespan (two years), exploitation levels of this species are highly dependent on recruitment, which in turn is highly dependent on environmental conditions.
Lesser spotted dogfish (Scyliorhinus canicula)
This bentho-demersal species is found on gravely and sandy substrates of the continental shelf. Adult lesser-spotted dogfish feed on gastropod molluscs, bivalves, cephalopods, crustaceans, polychaete worms and small fish. The species is oviparous with internal fertilisation. Eggs are more or less rectangular capsules about 6 cm long and 2.5 cm wide with horns at the corners. The horns are prolonged by filaments that enable the female to attach eggs to the bottom (rocks, algae, etc). Eggs hatch after three to eight/nine months incubation depending on water temperature, and at birth, juveniles are 10cm long. This species is of low commercial interest and hence is rarely targeted (bycatch species of French vessels).
Atlantic herring (Clupea harengus)
This is a pelagic fish forming schools, feeding on zooplankton (copepods, amphipods and mysids) following a diel vertical migration: between deeper waters by day and the sea surface at night. After fertilisation, eggs descend to the bottom where they stick to the gravely substrate until hatching, which occurs after two to three weeks. Fry are then transported to the surface where they drift with the currents until they are able to swim actively at 12 mm in length. Herring in English Channel belongs to the North Sea stock, constituted of three main populations which spawn in different seasons and areas. One of these, Downs herring, spawning in the English Channel from November to January, is considered a fragile population but one of which is essential for the stability of the North Sea stock as a whole. It was the first to show signs of decline during the mid-1960s. This component of the stock is less fecund than the others and has been over-exploited.
Atlantic horse mackerel (Trachurus trachurus)
A pelagic and gregarious fish, the horse mackerel lives in midwater or on sandy substrates. Adults form large schools in coastal waters having a sandy substrate, and they often shoal with juvenile herring. Horse mackerel is a migratory fish. Horse mackerel larvae, depending on their size, mainly feed on copepods (larvae and adults). Juveniles also ingest mainly copepods, as well as ostracods, mysids, fish (goby, sandeels, etc). Adults feed on fish (anchovy, sprat, sardine, herring, etc), cephalopods and crustaceans. Horse mackerel is a relatively low-value commercial species and in the past, most of the catches were considered as by-catch (and used for fish meal). Nowadays, landings come mainly from large pelagic trawlers targeting mackerel or herring.
Poor cod (Trisopterus minutus)
This is a demersal and gregarious fish. It is mainly found in offshore waters at depths between 30 and 300 m, and muddy or sandy substrates. Only young individuals are found in shallow waters, often seen in and around wrecks, or in cracks or crevices of rocky substrates. Adults mainly feed on decapods (shrimps and crabs) plus small fish and polychaetes. Breeding occurs from February to May, with a peak in March-April.
Atlantic cod (Gadus morhua)
Cod is a bentho-demersal species, which can also be found in the water column, and a boreal species ranging from marine to brackish waters characterised by temperatures between 0 and 20°C. Adult cod are active predators feeding especially at dawn and dusk on invertebrates (crustaceans, decapods, cephalopods and worms) and small fish, and living during the day in schools that break up at night. Pelagic eggs hatch after twelve days, and the larvae will stay in the water column for two to five months before migrating to the bottom. The stock considered here, from the North Sea and eastern English Channel, experienced their highest exploitation levels in the 1970s-1980s. Since then, stocks of cod have continually declined and they are now well below the biologically safe limits. Traditional measures of stock regulation such as the quotas have been insufficient to ensure a balance between the resource and its exploitation rate, and therefore a cod recovery plan was established in 2003. The plan aims at reducing fishing pressure by those cod fisheries that have the strongest impact on the species. Because the spawning biomass is in a critical condition, exploitation of cod depends mainly on the catch of juveniles and the strength of recruitment.
Dragonets (Callionymidae)
This is a benthic species living on sandy and muddy substrates, sometimes under stones. Dragonets are territorial, males aggressively defending their territories. Breeding occurs between February and August, with a complex courtship behaviour consisting of four phases - courtship, pairing, ascension to the surface, and release of pelagic eggs and milt. The larvae are also pelagic. Dragonets feed on small bottom invertebrates, mainly annelid worms, snails and crustaceans. They constitute an abundant prey for many demersal species.
Red mullet (Mullus surmuletus)
Red mullet is a benthic fish that lives on pebbly, gravelly and sandy substrates. Adult red mullet feed on small crustaceans, annelid worms and molluscs, using their chin barbels to detect prey and search the mud. In the English Channel, spawning occurs from May to July. After hatching, the pelagic larvae absorb their vitellus in 4 days, and they migrate to the coast in the autumn. Juveniles of length greater than 5 cm return to sandy and shelly substrates deeper than 10 m. Growth during the first year of life is particularly fast. This fish is important to the artisanal fishery because of its high commercial value. Regarded as a noble species by the fishers, the red mullet is mainly exploited by France. As there is no size limit for this species, landings span the whole size spectrum including juveniles. Landings started to increase after 1990. Although relatively stable until 1994, they increased rapidly in the following decade. Since 2004 the abundance of red mullet has shown a downward trend.
Whiting (Merlangius merlangus)
This is a bentho-demersal species that lives on gravely or muddy substrates. The diet of adult whiting includes shrimps, crabs, molluscs, small fish, polychaetes and cephalopods. In the eastern English Channel, spawning takes place from January to June. Eggs are pelagic, and larvae and juveniles are often associated with jellyfish, and do not become demersal until they reach 5 to 10 cm in length. Juveniles are essentially found in coastal waters (5 to 30 m in depth). Data on juvenile and adult distributions suggest movements between the North Sea and the eastern English Channel: it is likely that spawning adults come to the eastern English Channel to spawn during the first quarter, which corresponds to the fishing season in this area, and then migrate northward as waters progressively warm. From 1989 to 2001, whiting landings have been relatively stable, with a maximum of 8,500 tonnes in 2001. Since then, landings have decreased quickly down to approximately 3,400 tonnes in 2006.
The whiting stock is managed at EU level, using TAC and minimum landing size. The fishing mortality may have increased in recent years, and spawning stock biomass may have reached an historical minimum in 2008. Recruitment levels have been low since 2001.
European plaice (Pleuronectes platessa)
This bentho-demersal species prefers to live on sand but also on gravely or muddy substrates. Adult plaice essentially feed on polychaetes, bivalves, coelenterates, crustaceans, echinoderms and small fish. In the English Channel, spawning occurs from December to March at depths ranging from 20 to 40 m. Initially, pelagic eggs generally float at the surface. They then progressively sink into deeper waters during their development. Larvae spend about 40 days in the plankton before metamorphosing (when 10-17 mm in length). They then move to the bottom and migrate towards coastal waters. The fry undergo relatively fast growth during the first year. At the international level, plaice is one of the most landed flat fish, with nearly 11,000 tonnes being landed in 2000 from the eastern English Channel and southern North Sea, where it represents an important economic part of the artisanal fishery. The ICES working group considers that European plaice in the north-east Atlantic to be divided into two stocks: VIId (Channel) and IV (mer du Nord), but discussions are still undergoing as there is connectivity between these stocks. International catches have shown a steady decrease since 2001.