Effects of Lunar Phases and Other Variables on CPUE of European Pilchard, Sardina pilchardus, Caught by Purse Seine in the Eastern Mediterranean

Abstract

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.

The influences of temporal-spatial parameters on CPUE of the Atlantic bluefin tuna purse seine fishery in eastern Mediterranean

“…The objective of the present study is to assess the impact of spatial, temporal variables and vessel length on the CPUE of ABFT in the purse seine fishery. While previous studies have utilized GAM to standardize CPUE and examine variable influences (Damalas and Megalofonou, 2012; Zhou et al ., 2019; Tosunoglu et al ., 2021), this study represents the first application of GAM to the CPUE indices of purse seine fleets targeting ABFT in the eastern Mediterranean. By incorporating spatial variables into the GAM model, we aimed to gain valuable insights into the spatial dynamics of ABFT, enhance predictive accuracy and facilitate informed decision-making for the management and conservation of this species.…”