Preprint volume - SIBM

Pre-print Volume –Oral presentations
Topic 4: THE ELASMOBRANCHS
P. SARTOR, I. ROSSETTI * , G. BALDUCCI * , M. LARICCIA * , M. SBRANA, S. DE RANIERI
C.I.B.M. – Consorzio per il Centro Interuniversitario di Biologia Marina ed Ecologia Applicata “G. Bacci”,
V.le N. Sauro, 4 – 57128 Livorno, Italy.
psartor@cibm.it
* Consorzio Unimar S.c.r.l., Roma, Italy.
FISHERMEN PERCEPTIONS ON THE ELASMOBRANCH ABUNDANCE
EVOLUTION OVER TIME IN THE ITALIAN TRAWL FISHERIES
EVOLUZIONE TEMPORALE DELL’ABBONDANZA
DEGLI ELASMOBRANCHI NELLA PESCA A STRASCICO ITALIANA
SECONDO LE PERCEZIONI DEI PESCATORI
Abstract - This paper examines the long-term evolution in elasmobranch catches by Italian trawl fishery
from 1940 to the present. Historical data on catches and species composition were collected by fishermen
interviews. The results, validated by the available scientific literature, show an evident temporal decline for
many species and, in some cases, the complete disappearance from the catches.
Key-words: trawling, elasmobranchs, depletion, temporal variation.
Introduction - Recent studies show that the population abundance of sensitive marine
species, such as elasmobranchs, decreased during the XX century in the Mediterranean
Sea (Ferretti et al., 2008). Demersal sharks like Squatina spp. and Mustelus spp. were
relatively abundant until the 1950s and locally were the target of small-scale fisheries;
these species have at present practically disappeared from the commercial catches and
are only occasionally caught through experimental surveys (Aldebert, 1997).
The present study is targeted to provide a picture on the temporal evolution of
elasmobranchs abundance in different Italian trawl fisheries starting from the 1940’s,
according to information collected by interviews to old or retired fishermen.
Fishermen perception can be a source of information complementary to scientific data.
According to Freire and Garcia Allut (1999), traditional ecological knowledge of
fishermen (TEK), could add new data in marine ecology and fisheries biology. If
interviews to fishermen are performed through a standardised approach with well
structured questionnaires, not only qualitative, but also quantitative or semiquantitative
data could be gathered (Bergmann et al., 2004). At present, this approach
has been applied only in small Mediterranean areas (Sardà and Maynou, 1998).
Materials and methods - In the framework of the UE project “EVOMED (“The 20 th
Century evolution of Mediterranean exploited demersal resources under increasing
fishing disturbance and environmental change” (Sartor, 2010), 50 interviews to old or
retired fishermen were realised in different Italian Mediterranean areas: Ligurian Sea,
northern and central Tyrrhenian Seas (GFCM-FAO GSA 9) and northern Adriatic
(GFCM-FAO GSA 17).
In the selection of the fishermen to interview, preference was given to vessel Captains.
Information has been collected according to a standardised questionnaire and interview
protocol. The main contents of the questionnaire concerned information on vessels
characteristics, fishing gears and fishing grounds, as well as on catches (main target
species, discards, etc). The questionnaire was designed to gather information for three
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
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