Assessing the influence of the North Atlantic Oscillation on a migratory demersal predator in the Alboran Sea

Abstract

This study analysed the regime shift of tope shark and the overlapping taxa Raja spp. in the Alboran Sea. Tope shark and Raja spp. landings are both significantly correlated with the North Atlantic Oscillation (NAO). A significant negative correlation was found between Raja spp. landings and tope shark landings. This finding suggests that climatic oscillations affect regime shifts between these taxa in the Alboran Sea. Studies are scarce on the dependence of deep-sea communities on biological and physical processes occurring in near-shore pelagic environments mediated by large-scale atmospheric phenomena. Similar to previous studies on the Mediterranean Sea, a close association was found between landings of deep-water animals and the NAO. The main conclusion is that the regime shift of tope shark and the overlapping taxa Raja spp. is mediated by a negative NAO and accumulated snow.

Traditional fishery of Dolphinfish (Coryphaena hippurus) in the Gulf of Hammamet, Tunisia: implications for management of the entire Mediterranean fishery

“…The air temperature is also correlated with the abundance of the resource, because of its influence on variations in surface temperature [32] . It also conditions the fishing effort by the number of days available for fishing.…”

“…These fluctuations may be due to both annual spawning failures and /or insufficiency of new recruits to the fishery, but the ultimate explanation must be sought in the underlying environmental factors that control "recruitment windows" [20] . In fact, for most migratory and pelagic species these factors linked to the climatic and oceanographic conditions are influencing abundance, catchability, recruitment [32,39,40] . Therefore, climate change and global warming may have an impact on the distribution and overall trend of the resource abundance in the traditional fisheries.…”

Evaluation of harvest strategies for pelagic sharks taking ecological characteristics into consideration: an example for North Pacific blue shark

“…Their utilization of this productive area could therefore contribute to their high growth rate and the consequent high productivity of the blue shark(Ichii et al 2016). Mortality of sharks caused by fisheries has been recognized as one of the main factors driving the decline in their populations(Báez 2015). It could thus be important for shark conservation policies to understand the relationships between declines in the population and regime shifts(Worm et al 2013).…”