Search results for "Trawling"
showing 5 items of 15 documents
Trawl mesh selectivity and body engagement pattern in the red shrimpAristaeomorpha foliacea(Risso, 1827) (Crustacea: Decapoda)
1998
The paper presents selectivity data and utilizes an elliptic surface index (maximum height and width of the folded body), in order to explain the selectivity differences between sexes and to investigate the body engagement pattern of the red shrimp Aristaeomorpha foliacea. The results show that males are retained more, with significant differences, and demonstrates a previously unknown morphological difference between sexes (folded males are significantly higher than females of the same carapace length, while the latter are larger, but not significantly, than males of similar size). Nevertheless, in practice the overall escapement rate should not change dramatically with sex, since the resu…
Physiological stress indicators in the plasma of Scyliorhinus canicula captured by botto trawling at two depths.
2022
The quantification of capture-related physiological stress is an important factor when assessing the potential for post-release survival in sharks that are incidentally captured. In the absence of these biological data and when the post-release fate is unknown, effective management plans cannot be formulated and may lead to highly susceptible shark populations being overfished. Here, we measured the levels of lactate, glucose, alanine amino transferase (ALT), aspartate amino transferase (AST), Ca2+, Na+ K+,Cl - Mg 2+ and Pi in the plasma of mature and immature lesser spotted dogfish (Scyliorhinus canicula, herein dogfish) which were incidentally captured at two depths (shallow: 50-200 m, an…
Sizing up the role of predators on Mullus barbatus populations in Mediterranean trawl and no-trawl areas
2019
Abstract Fishing leads to drastic changes in ecosystems with a net loss of predatory biomass. This issue has been evidenced from historical ecological studies and from the evaluation of the effects of effective and large marine protected areas. In two fishery reserves off the northern Sicily coast the red mullet Mullus barbatus underwent an impressive biomass increment and a few piscivores fish species recovered after a trawl ban. The red mullet, more than 20% of all demersal fish in the untrawled areas, represented a huge food resource to its potential predators. By contrasting two trawled and two untrawled gulfs we figured out predator - prey relationships through the use of a combined ap…
Spatio-temporal composition of discard associated with the deep water rose shrimp fisheries (Parapenaeus longirostris, Lucas 1846) in the south-centr…
2017
Discarding in fisheries is the fraction of the total catch brought on board and returned to the sea dead or alive for legal or economic reasons. The reduction of discard is one of the main objectives of the European Common Fishery Policy. This study aimed to improve the current knowledge of the discard associated with the deep-water rose shrimp (DPS) fisheries in the south-central Mediterranean Sea. We analyzed data collected from January 2009 to December 2013. Multivariate data analysis and generalized additive models (GAMs) were used to assess the spatio-temporal composition of the discard (which represented 36% of the total catch) and factors influencing its distribution. Multiple analys…
Density and biomass of smelt (Osmerus eperlanus) in five Finnish lakes
2005
Abstract Hydro-acoustic stock assessment and exploratory sampling with small mesh-sized trawls and seines have sometimes suggested that the importance of smelt (Osmerus eperlanus) in pelagic fish communities might be greater than sampling from commercial fishery and gillnetting indicate. We studied the proportion of smelt in the total fish density (fish ha−1) and biomass (kg ha−1) of pelagic fish with echo sounding and trawling in five southern boreal lakes. Fish density varied between 460 and 2000 fish ha−1 in the study lakes. Smelt and vendace (Coregonus albula) accounted for more than 95% of the exploratory trawl-catches. The total fish biomass in the study areas varied between 3 and 13 …