Untitled - CNR

Fishery and Sea ResourcesFigure 6: Haemolytic activity in Dicentrarchus labrax cultured in submerged (sub) andsurface (surf) cages. Reported are the result of the Student t-test: ∗ = p < 0.05,∗∗ = p < 0.01, no indications is reported when difference is not significant.on some components of innate immunesystem of cultured fish.Moreover results of immunological parametersare in agreement with those haematologicaland biochemical and seem to furtherconfirm the hypotesis that submergencepromotes sea bass welfare.4 Conclusions and futureperspectivesThe research provides for the first time dataon stress assessment in submerged cages, aparticular rearing condition. In off-shorecages, where handling or other stressorscurrently acting in intensive practices donot affect the quality of the final products,the main negative factor that may influencethe specimens reared is mainly referableto chronic stress condition with a continuousdisturbance due to the growth itself andconsequent increase of the specimen size.Submergence seems to be a favourablecondition for sea bass culturing, as evidencedby growth, haematological, biochemicaland immunological parameters.One reason for this could be linked tostress response from predation. In fact, dueto predation activity (i.e. birds attacks),surface-based fish farming can become anenvironment favouring high mortalities, injuryand stress; in a research on dynamicsof predation, Dieperink [36] refers that aflock of cormorants are able to empty thepound net in about 30 minutes and consume110 fish weighing a total of approximately50 kg.This hypothesis is, also, supported bystudies on neuroendocrine perception ofstress in fish where is demonstrated thatprey/predator encounter is a stressful situationand induce a stress response with energycost for escape [37].2156