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Fishery Bulletin 103(4) 



Shortfin mako {Isurus oxyrinchus), common thresher 

 shark (Alopias vulpinus), and tope shark (Galeorhinus 

 galeus) were the next most abundant shark species and 

 were found in more than half of the areas sampled. 

 The rest of the shark species identified were the por- 

 beagle (Lamna nasus), bigeyed thresher shark {Alopias 

 superciliosus), smooth hammerhead iSphyrna zygaena), 

 bluntnose sixgill shark (Hexanchus griseus), sandbar 

 shark (Carcharinus plumbeus), longnose spurdog tSqua- 

 lus blainvillei), smoothhound (Mustelus mustelus), and 

 basking shark (Cetorhinus maximus). 



The proportions of shark catches were significant- 

 ly different among fishing gears (x 2 = 15970.7, df=36, 

 P=0.000<0.001). Total shark catches in biomass rep- 

 resented 17.7% on swordfish longline gear, 11.3% on 

 driftnet gear, and only 0.3% on albacore longline gear 

 (Table 3). Comparisons of catch composition among the 

 fishing gears in the same area showed similar results. 

 In the Ionian Sea, shark percentage was higher in the 

 swordfish longline catch than in the driftnet and alba- 

 core longline catch (Table 4). Catch composition also 

 differed significantly by area (% 2 = 494558.4, df=112, 

 P=0.000<0.001). The higher percentage of sharks, 

 34.3%, was found in the Alboran Sea and the lower 



percentages, in the Straits of Sicily and the Catalonian 

 Sea (Table 5). Statistically highly significant differ- 

 ences were detected in catch composition among types 

 of sampling ( X 2 =29760.41, df=17, P=0.000<0.001). In 

 all fishing gears and areas examined throughout the 

 Mediterranean Sea, sharks represented 15.3% of the 

 total catch in biomass at landings and only 5.3% on- 

 board vessels. Among areas sampled, three areas (the 

 Alboran Sea, Catalonin Sea, and Balearic Island area) 

 revealed higher shark percentages at landing sites than 

 onboard vessels (Table 5). 



Relative shark abundance varied between fisheries. 

 Higher shark catch rates were observed in swordfish 

 fisheries both onboard vessels and at landing sites 

 (Table 6 and 7). Overall CPUE reached 1.30 and 0.56 

 fish/1000 hooks in SWO-LL and SWO-LL A , respectively 

 (Table 8). Shark catch rates were higher in the Alboran 

 Sea and the Adriatic Sea, where the average CPUEs 

 were 3.80 fish/1000 hooks and 1 fish/1000 hooks, re- 

 spectively in SWO-LL (Table 8). The driftnet fishery 

 had a catch rate of only 0.04 fish/1000 m of nets. The 

 comparison of catch rates (number of shark per set) 

 among the different gear types in the same area (the Io- 

 nian Sea) revealed that the highest CPUE values were 



