Preprint volume - SIBM

Pre-print Volume –Oral presentations
Topic 4: THE ELASMOBRANCHS
Tab. 1 – GSA 9, fishermen interviews. Percentage contribution of elasmobranchs to the total catch
over time.
GSA 9, interviste ai pescatori. Variazione nel tempo del contributo percentuale degli
elasmobranchi alle catture totali.
Mean % Elasmobranch
contribution to the total catch
From 1940’s
to 1960’s
From 1960’s
to 1980’s
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
212
From 1980’s to
present
14.2 (±13.4) 10.3 (±11.4) 5.3 (± 4.8)
The decrease reported by fishermen was observed especially for some species, like
Mustelus spp., Squalus spp. and Squatina spp. In particular, it was noticed that in the
fishing grounds of GSA9 the abundance of species like Squatina spp. was already
reduced in the earlier period (1940-1960). The last catches of Squatina spp. were dated
to the end of 1970’s, while many fishermen reported that Mustelus spp. have been
caught abundantly until the middle of 80’s.
A total of 15 interviews were performed in Civitanova Marche, central Adriatic Sea
(GSA 17). The main species caught over time by the interviewed fishermen were the
same of those reported by the fishermen contacted in GSA 9.
Also in Civitanova Marche an evident decrease of catches of elasmobranchs over time
was reported. About 95% of interviewed noticed that the catches of sharks and rays
observed until the 1980’s were more abundant than those at present (Fig. 2). On the
other hand, it emerged that the catches of the more recent period did not show evident
differences with those of the present. A similar pattern results from the temporal
evolution of the percentage contribution of elasmobranchs to the total catch (Tab. 2).
100%
75%
50%
25%
0%
1940-1959 vs
present
1960-1979 vs
present
1980-2008 vs
present
Less abundant
The same
More abundant (two times)
M uch more abundant (more than three times)
Not able to evaluate
Fig. 2 – GSA 17, Fishermen interviews. Comparisons of the elasmobranch catches of different time
periods with those of the present.
GSA 17, interviste ai pescatori. Comparazione delle catture di elasmobranchi di diversi
periodi con quelle attuali.