The ballan wrasse ( Labrus bergylta) is a species of marine ray-finned fish from the family Labridae, the . It is found in the eastern Atlantic Ocean, where it inhabits rocky areas. Like many wrasse species, it is a protogynous hermaphrodite—all fish start life as females, and some dominant fish later become males. It is used as a food fish in some areas and it is also finding use as a cleaner fish in the aquaculture of Atlantic salmon ( Salmo salar) in northwestern Europe.
Description
The ballan wrasse is a large, heavy bodied wrasse with a relatively deep body and large head. It has a smallish mouth which is surrounded by thick, fleshy, rather wrinkled lips, and the jaws are armed with a single row of robust teeth which are sharp and pointed in young fish but blunter and more worn in older fish. It has a long
dorsal fin which has 18–21 spines in its anterior portion and 9–13 branched rays in the rear part. The
anal fin is markedly shorter and has three spines. It has large scales with 41–47 of them in the
lateral line. The juvenile fish are coloured to match their habitat and vary in from light green to dark green,
with some being described as bright emerald green.
Adult Ballan wrasse are highly variable in colouration, but have two main colour forms, which exist in sympatry with each other. One is plain green or brown, and the other is reddish with white spots. This is not a result of sexual dimorphism, as males and females can both exhibit either colour form. Spotted Ballan wrasse grow larger than plain coloured individuals. The two colour forms are commercialized separately in places such as Galicia, where local fishermen often treat them as separate species.
It can grow to in fish measurement (though most do not exceed standard length), and the greatest recorded weight of this species is . Ballan wrasses are protogynous hermaphrodites.
Ballan wrasse are classic labriform swimmers,
Distribution
Ballan wrasse are native to the northeastern Atlantic Ocean from
Norway to
Morocco, including the islands of
Madeira, the
Azores and the
Canary Islands. There are records from the Mediterranean Sea but these are regarded as questionable
and may be misidentifications of the
brown wrasse (
Labrus merula).
[
]
Habitat and biology
They can be found at depths from amongst rocks, seaweed and reefs. All ballan wrasses are female[ The thick lips and sharp front teeth of the ballan wrasse are an adaptation for extracting shellfish from rocks. These are supplemented by powerful pharyngeal teeth which are placed further back in the throat and which can break up shells to access flesh inside. This species also feeds on and their diet includes hard-shelled crabs and small lobsters. They will swim into shallower water so that they can prey on the shellfish which cling to underwater cliff faces and inshore rocks. They will also inhabit areas with good covering of kelp and other seaweeds.][ The male builds a nest of algae in a crevice in the rocks in which one or more females lay eggs. The male defends the nest until the eggs hatch into pelagic larvae after a week or two.]
Ballan wrasse do not have stomachs.
Human usage
Fishery and sport
This species is popular as a food fish in the Orkney Islands off the north-eastern coast of Scotland, and in Galway, a county in the west of Ireland.[Alan Davidson, North Atlantic Seafood, 1979, ] However, it is not highly regarded as a food fish in much of the UK and Ireland.[David Erwin, Bernard Picton, "Guide to Inshore Marine Life" The Marine Conservation Society 1987 ]
Aquaculture
This fish is one of 5 key species used as cleaner fish to remove sea lice from Norwegian
As with many farmed marine species, commercial larval rearing utilises live prey before transitioning to dry feeds after metamorphosis is complete.
This species can also be found in the aquarium trade.
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