engleski

Small-scale fisheries in Croatia

Coastal waters are one of rather important fishing grounds of the eastern Adriatic Sea. The area is the most productive Adriatic zone owing to the vicinity of the land and fresh water inflows. The coastal eastern Adriatic has been heavily exploited because a large number (>50) of fishing gears are used there. Changes in the communities of fish and edible invertebrates are manifested as changes in quantitative and qualitative catch structure. The long-term monitorings of coastal communities could provide information on the trend and intensity of those changes. The beginning of analyses of catch by coastal fishing gear along the eastern Adriatic coast can be traced back to the fifties of this century. Thus, an almost 50 year data series on the quantities and species composition of trammel bottom set catches is available. The state of the coastal communities in 2006 and comparation with this long-term data are reported and discussed here. Those data are results from monitoring project Pag-Konavli (previousely Vir-Konavli). The used tremmel bottom sets are, undoubtfully, very efficient and almost non-selective fishing gear owing to their construction properties and specific way of fish trapping. These were the reasons why they were choosen for this approach of estimation the structural changes in coastal communities. Presented results showed that current state of coastal ichthyocommunities (together with cephalopoda and crustacea catches) in the eastern Adriatic Sea is satisfactory. The CPUE (catch per unit effort) was seasonally in a range from 0.78 to 1.3 kg. The best catces were in Vis area (in quantitative and qualitative sense) due its distance from land, pointing once again that off shore fishing grounds are more abundant and diverse than coastal zone. However, it should be emphasized that even those islands areas, which are far off the mainland and under smaller fishing effort, showed decrease in total CPUE and biodiversity. But, mean values of basic biometric characteristics of dominant species are not satisfactory. Moreover, mean values of total length of Scorpaena scrofa and Diplodus vulgaris are very low showing a great intensity of fishing in costal area. Qualitatively, catches are very uniformely distributed. On each area, only 4-5 species were dominant, although even 82 fish species were caught. Dominant fish species for whole areas are S. porcus, D. annularis, M. surmuletus, P. erythrinus, S. scrofa and S. tinca. Dominant crustacean was Squilla mantis while S. officinalis was dominant cephalopoda. However, catches are biologicaly diverse. Looking in long-term data sets, the values of CPUE are significantly greater than those in 80ties. But, it has to be mentioned that populations of commercially interesting fish (S. scrofa) and big Decapoda species (P. elephas, H. gammarus) are still not recovered (rare catches of individuals with high biometric characteristics). Particularly, (i) decline in total CPUE by different areas (ii) increase in the CPUE of some familly, as Scorpaenidae, and decline of some, as for example Labridae or Serranidae, and (iii) changes in the length frequency distribution of dominant species in the catches are visible. The reasons of recent positive changes are better implementation of legal measures concerning the exploitation and protection of marine biological resources, but evidently, intensive fishing activities, which affect coastal communities and effect interspecific and intraspecific relations in Croatian coastal area is still present. Different species vulnerability to fishing activity is also a cause of those changes. But, most of authors believed that the main reasons for observed state is intensive fisheries. Growing marine pollution additionally affects this area, particularly in the vicinity of large urban and industrial centers, as it was case for sampling stations of this investigation. Moreover, the climate changes in hydrographic nature have influenced changes in the quantitative and qualitative composition of the fish fauna in these regions by more intensive influx of eastern Mediterranean water in Adriatic Sea.

small-scale fisheries; status; trend; Croatia

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