European pilchard Sardina pilchardus (Walbaum, 1792) is one of the most dominant small pelagic landed by purse seine in Turkey as well as Mediterranean. In this study, we aimed to identify relationships between the seasonally adjusted CPUE and changes of the sea surface temperature (SST), fishing area, moon phase, and light used in the purse seine fishery to understand the impact of changes on the CPUE of pelagic fishes, especially S. pilchardus, by a total of 214 operations in Izmir Bay, Aegean Sea. The effect of the parameters on the Sardine CPUE, expressed in terms of kg (haul day)–1, was examined by means of the Generalized Additive Modelling (GAMs) techniques. The CPUE values for S. pilchardus were between 0 – 16 800 kg (haul day)–1 and the mean CPUE was 1 844.3±176.6 kg (haul day)–1 . The smallest median was 441 kg (haul day)–1 for full moon and the differences between the CPUE values of lunar phases were statistically significant (p<0.05). Furthermore, there is a linear relationship between CPUE and SST. In conclusion, the CPUE varied under hydrographic variables mostly SST for sardine purse seine fishery in the Aegean Sea.
Discard mortality of European anchovy (Engraulis encrasicolus) and European pilchard (Sardina pilchardus) was investigated during commercial purse seine fishing operations off İzmir Bay, Turkey. In total, 6703 anchovy and 2545 sardine individuals were observed for seven days in five survival experiments carried out from March to October 2019. Only in March, fish cages were used and observed by divers. In the other trials, fish were observed in holding tanks; dead fish were collected and any surviving fish were fed. In the study, we compared the mortality of sorted and unsorted fish. The GLM model for European anchovy demonstrated a highly significant category effect (p<0.0001) and a highly significant interaction between length-related mortality and season (CL: season; p<0.0001). There were also significant differences in length-related mortality ratio according to the different categories in both seasons (p<0.0001). However, there was a highly significant interaction between mortality ratio, length, uncrowded category, and spring (p<0.005) for European pilchard. The observations showed that high mortalities occurred in the sorted fish categories of both pelagic species during the experiments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.