Distributional pattern of rays (Pisces, Rajidae) in the Strait of Sicily in relation to fishing pressure

Published source details Garofalo G., Gristina M., Fiorentino F., Cigala Fulgosi F., Norrito G. & Sinacori G. (2003) Distributional pattern of rays (Pisces, Rajidae) in the Strait of Sicily in relation to fishing pressure. Hydrobiologia, 503, 245-250.
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This study is summarised as evidence for the following.

	Action	Category
	Limit the number of fishing days Action Link

Limit the number of fishing days

A before-and-after study in 1985–2002 of an area of seabed in the Strait of Sicily, Mediterranean Sea, off Italy (Garofalo et al. 2003) reported that following a decrease in the overall number of days fished (or fishing effort) by a bottom trawl fleet there was an increase in biomass of thornback ray Raja clavata and brown ray Raja miraletus. Data were not tested statistically. Total ‘days’ fished decreased to 11,000–12,000 hrs/season in 1997–2002, from 16,000–32,000 hrs/season in 1985–1996. Over the same period (1997–2002) average biomass of thornback ray increased (6.0 to 8.0 kg/km²), as did average biomass of brown ray (3.4 to 5.0 kg/km²) following an earlier decline in 1985–1996 (4.0 down to 3.0 kg/km²). In the late 1980s and early 1990s changes to the Mazara del Vallo trawl fleet in the Strait of Sicily (fewer small coastal vessels to more large trawlers designed for offshore fishing) resulted in a large reduction in fishing effort in overexploited areas, as fishing activity moved to other areas. Ray abundance data were collected during scientific trawl surveys conducted in 1985–86, 1990–91, 1994–98 and 2000–02. The vessel used was a commercial charter that deployed an ‘Italian Bottom Trawl’ of 28 mm codend mesh size. Fishing effort data were derived from Harbour Office records and interviews with fishers.

(Summarised by: Natasha Taylor)