Biophysical Factors Controlling the Distribution of Veined Squid Loligo forbesii at Its Northern Extent

Climate change impacts the distribution and abundance of marine animals. Change in these parameters can alter ecosystem dynamics and trophic interactions among species. Successful conservation and management rely on our ability to explain and predict distribution changes. This study provided the first description of the temporal and spatial distribution of Loligo forbesii at its northernmost edge and assessed biophysical parameters that influence its presence. The study used data from bottom trawl surveys sampled in the waters surrounding the Faroe Islands from 1994 to 2023. We first investigated the spatial and temporal variation of observed presence among different stages (paralarval, juvenile, and adult) (Model 1). We then explored the environmental parameters (bottom depth, day of year [DoY], temperature, and salinity) that explain these spatiotemporal patterns in presence (Model 2). Model 1 identified that 31% of the variability in squid presence across stages could be explained by year, location, and the interaction between the two. The highest probability of presence was at the Faroe Bank followed by the Faroe Plateau. Probability of presence peaked in 2013 in all areas. Model 2 identified how the presence of squid increased with temperature, decreased with bottom depth, and fluctuated with DoY consistent with L. forbesii's spawning period. Together, these predictors explained 17.5% of the variation in probability of presence. There was some evidence that salinity also affected the probability of presence. These results are discussed with respect to underlying mechanisms and the possible future presence of L. forbesii in the area.