Biology, spatial distribution and population dynamics of Lepidotrigla cavillone (Pisces: Triglidae) in the Central Tyrrhenian Sea

Specimens of Lepidotrigla cavillone (the large-scaled gurnard) were collected in the Central Tyrrhenian Sea during trawl surveys carried out in April-May and September 1985, 1986, 1987, 1994, and in October 1995. The species was fished between 30 and 200 m depth. A significant size-depth relationship (p < 0.001), was observed for juveniles (S.L. < 7 cm) and adults: the former migrated deeper from the coastal nursery, at the end of the first year of life; the latter moved shallower toward the spawning grounds at 60-100 m depth. Principal Component Analysis, indicated gonadal development as the main factor affecting L. cavillone depth-size relationships. Mature females were observed with significantly higher abundance (p < 0.001) at depth of 80-100 m. Large-scaled gurnards accomplished more than half of their growth during the first two years. Reduction of growth coincided with attainment of sexual maturity. An increase of the mesh size towards the legal size may bring the age at first capture from 1.5 years up to the age of first maturity (second year) improving current Y/R.