fishing effort and catch composition on the boundaries of

Biol. Mar. Mediterr. (2010), 17 (1): 340-341
A. Indennidate, R. Carlucci, P. Maiorano, L. Sion, G. D’Onghia
Department of Animal and Environmental Biology, University of Bari,
Via E. Orabona, 4 - 70125 Bari, Italia.
[email protected]
FISHING EFFORT AND CATCH COMPOSITION
ON THE BOUNDARIES OF SANTA MARIA DI LEUCA
DEEP-WATER CORAL BANK
SFORZO DI PESCA E COMPOSIZIONE DELLE CATTURE AI MARGINI
DEL BANCO A CORALLI PROFONDI DI SANTA MARIA DI LEUCA
Abstract - As part of EU-FP7 CoralFISH project, the “Observers’ Program” activity has been
carried out to investigate on the fishing effort and catch composition from longline and bottom trawl
fishing carried out near the Santa Maria di Leuca (SML) coral bank (North Western Ionian Sea).
Key-words: fishing effort, catch composition, deep-water coral reefs, Mediterranean.
Introduction - The Santa Maria di Leuca (SML) coral bank is characterized by
living Lophelia-Madrepora-bearing coral mounds, widespread in an area of about
900 km2, between 350 and 1100 m depth, in the northern Ionian Sea (southern Italy)
(Taviani et al., 2005, D’Onghia et al., 2010). The bank represents a Mediterranean
deep-water biodiversity “hotspot” (Mastrototaro et al., 2010) which could also play
an important role as nursery and spawning area for demersal species (D’Onghia et
al., 2010). In this work, information on fishing effort and catch composition observed
on the boundaries of this deep-water coral bank is provided.
Materials and methods - Data were collected from June to October 2009 within
the Observer Program, carried out in the framework of the EU-FP7 CoralFISH
project. Fishing effort and catch composition data were collected from longline
and bottom trawl. In particular, the following data were recorded: date and hour
of fishing, set time and number of hooks (if longliner), haul time (if trawler), seaweather conditions; fishing zone with indication of depth, latitude and longitude;
catch composition (both commercial and discard species) with number and weight;
by-catch of corals and sponges (and other invertebrates).
Results - Seven trawlers and one longliner usually fished on the boundaries of
SML deep-water coral bank. Both the number of fishing days per month (Tab. 1)
and geographic distribution of fishing hauls (Fig. 1) varied largely throughout the
investigated period according to the sea-weather conditions. Sometime trawlers
fished inside the northward limit of the coral area. Catches from trawling mostly
consisted in Merluccius merluccius, Illex coindetii, Aristaeomorpha foliacea and
Aristeus antennatus while those from longline were mainly made of Chelidonichthys
lucerna, M. merluccius and Conger conger (Fig. 2).
Tab. 1 - Fishing days per month and gear recorded in SML fishery during the “Observer Program”.
Giornate di pesca per mese e attrezzo registrate nella marineria di SML durante l’Observer Program.
June 2009
July 2009
August 2009
September 2009
October 2009
trawl net
32 (4)
46 (7)
29 (6)
closed season
18 (3)
longline
16 (1)
12 (1)
8 (1)
15 (1)
5 (1)
(*) in brackets the number of recorded vessels.
Fishing effort and catch composition on the boundaries of Santa Maria di Leuca deep-water coral bank
341
Fig. 1 - Distribution of the fishing
hauls recorded in SML fishery
during the “Observer Program”.
Fig. 2 - Catch composition from longline and trawl net
recorded in SML fishery during the “Observers’
Program”.
Distribuzione delle cale di pesca
registrate nella marineria di SML
durante l’Observer Program.
Composizione delle catture ottenute con palangaro e
strascico nella marineria di SML durante l’Observer
Program.
Conclusions - Fishing operations of both longliner and trawlers occurred close or
even inside the northward limit of the coral area, indicating the occurrence of the
“fishing the line” phenomenon (Roberts and Hawkins, 2000). This occurs with the
aim of obtaining greater catches and larger specimens. Catch composition showed
that, apart from M. merluccius and P. blennoides, the two types of gears select
different resources. C. lucerna, fished with the greatest abundance by longline, was
never collected inside the coral area being distributed in shallower waters. Some other
species, such as M. merluccius, P. blennoides and H. dactylopterus, were collected
with greater abundance inside the coral bank than outside (D’Onghia et al., 2010).
For some of them a spill-over effect, providing benefit to SML fishery, might occur.
Although the present results did not show any particular fishing pressure on this
Mediterranean coral habitat, a fishermen self-regulation appears to be fundamental
even considering the new legal category of “Deep-sea fisheries restricted area”
created by the GFCM for the SML deep-water coral bank.
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