engleski

Discarding practices in the commercial trawl fisheries in the eastern Adriatic Sea

Discards of unwanted or undersized fish and other non-target species represent a significant proportion of global marine catches that enhance the negative impact of fishery, especially when using fishing tools with low selectivity as bottom trawl nets. In order to estimate both retained and discarded catch composition of the commercial trawl fisheries in the eastern Adriatic, we used scientific observer records during 2010 and 2011. A total of 49 fish species, 12 cephalopods and 7 crustaceans were recorded in the catches, of which 29 species were always discarded and 39 species were only partially retained (discarding practice was generally market-driven). During the investigation period, it was estimated that 76.5% of the total catch by number and 39.6% by weight were discarded. When focused only on the sampled fish species, 18 were always discarded with Seranus hepatus, Boops boops, Gadiculus argenteus, Lepidopus caudatus, Lesueurigobius friesii and Callionymus sp. being the most numerous among them. On the other hand, the most abundant commercial fish species that were only partially discarded were Merluccius merluccius, Trachurus sp., Lophius budegassa, Mullus barbatus, Lepidorhombus sp. and Micromesistius poutassou. Estimated percentages of discard for these species were as follows: for M. merluccius 49.2% by number and 12.4% by weight, for Trachurus sp. 41.2% by number and 12.6% by weight, for L. budegassa 56.5% by number and 5.9% by weight, for M. barbatus 5.7% by number and 2.8% by weight, for Lepidorhombus sp. 84.4% by number and 48.4% by weight, for M. poutassou 79.7% by number and 73.3% by weight. Catches of M. barbatus were almost always retained and small amounts of discard mainly referred to the individuals of TL bellow 11 cm (MLS for this species) and therefore of no commercial interest for the fishermen. On the contrary, M. poutassou was usually discarded and was retained only when the overall catch was low. For the remaining four species, although discard percentages by weight may be considered as low, it should be noted that discard percentages by number are quite high and are further emphasizing the significant impact of discards on the state of fish populations.

trawl fishery; discard; Adriatic

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