Aim: Lanternfish (Myctophidae) are one of the most abundant and ecologically important families of pelagic teleosts, yet how these species will respond to climate change is unclear, especially within polar regions. The aim of this study is to predict the impact of climate change on the distribution of Southern Ocean lanternfish, and to relate these predicted responses to species traits. Location: Circumpolar, 35-75° S. Methods: We used MaxEnt ecological niche models to estimate the present and predict the future distributions of ten biomass-dominant lanternfish species throughout the region. Future conditions were simulated using eight climate models, in both stabilising (RCP 4.5) and rising (RCP 8.5) emission scenarios, for the time periods 2006-2055 and 2050-2099. Species responses were then related to their realised thermal niche (i.e. thermal tolerance range), latitudinal preference, and body size. Results: Despite large variation between climate model simulations, all but one species are consistently predicted to undergo a poleward distribution shift. Species show contrasting projections relating to a gain or loss of suitable habitat which was best explained by their thermal niche. Overall, high latitude Antarctic species were found to have narrower thermal niches and a higher likelihood of losing habitat than sub-Antarctic species. Main Conclusions: The direction of a species response was dependent on the interplay between physiology (realised thermal niche) and biogeography (latitudinal preference). Antarctic species with restricted thermal niches and limited available habitat in which to disperse will be the most vulnerable group of Southern Ocean lanternfish in the face of climate change. Predicted range shifts may alter the size structure of the myctophid community as smaller, sub-Antarctic species reach further south. This could have implications for trophic interactions and thus the wider Southern Ocean ecosystem as a whole.

occurrencedataThis file contains the cleaned and processed occurrence records of the ten myctophid species modelled in the study and present day environmental conditions associated to each presence locality. Please refer to the README file for further details.backgrounddataThis file contains the backgound data points used by the MaxEnt modelling algorithm and the present day environmental conditions associated to each background location. 10,000 background data points were selected randomly within 2 decimal degrees of mesopelagic fish records across the study region to control for spatial sampling bias. Please refer to the README file for further details.