Biogeography of Cephalopods in the Southern Ocean Using Habitat Suitability Prediction Models

Abstract

20Our understanding of how environmental change in the Southern Ocean will affect marine 21 diversity, habitats, and distribution remain limited. The habitats and distributions of Southern 22Ocean cephalopods are generally poorly understood, and yet such knowledge is necessary for 23 research and conservation management purposes, as well as for assessing the potential 24 impacts of environmental change. We used net-catch data to develop habitat suitability 25 models for 15 of the most common cephalopods in the Southern Ocean. Using modelled 26 habitat suitability, we assessed favourable areas for each species and examined the 27 relationships between species distribution and environmental parameters. The results 28 compared favourably with the known ecology of these species and with spatial patterns from 29 diet studies of squid predators. The individual habitat suitability models were overlaid to 30 generate a "hotspot" index of species richness, which showed higher numbers of squid 31 species associated with various fronts of the Antarctic circumpolar current. Finally, we 32 reviewed the overall distribution of these species and their importance in the diet of Southern 33Ocean predators. There is a need for further studies to explore the potential impacts of future 34 climate change on Southern Ocean squid.

Global Patterns of Species Richness in Coastal Cephalopods

“…Although cephalopod diversity and distribution have been studied extensively in the past, most such research and knowledge has been compiled as species accounts (see examples in Roper, 2005, 2010;Jereb et al, 2014). Large-scale biogeographic studies on cephalopod diversity are scarce and mostly concentrated in the Atlantic Ocean (Rosa et al, 2008a,b;Judkins et al, 2010), polar zones (e.g., Xavier et al, 1999;Allcock et al, 2011;Golikov et al, 2013;Xavier et al, 2016bXavier et al, , 2018 and the Pacific Ocean (Ibáñez et al, 2009(Ibáñez et al, , 2019 or specific taxonomic groups (e.g., Ibáñez et al, 2016;Ulloa et al, 2017). Moreover, some of those studies were designed to investigate broad-scale latitudinal gradients (e.g., richness and body-size data across latitudinal bins) and describe the respective environmental determinants (e.g., Rosa et al, 2008aRosa et al, , 2012Ibáñez et al, 2019).…”

Can we generate robust species distribution models at the scale of the Southern Ocean?

“…SDM are often applied to conservation issues and in Marine Protected Area designation processes (Franklin, ; Guisan et al., ; Rodríguez, Brotons, Bustamante, & Seoane, ). A growing number of large‐scale SDM‐based studies have recently been published for the SO (plankton, top predators, fish, and cephalopods) (Duhamel et al., ; Loots, Koubbi, & Duhamel, ; Nachtsheim, Jerosch, Hagen, Plötz, & Bornemann, ; Pinkerton et al., ; Thiers, Delord, Bost, Guinet, & Weimerskirch, ; Xavier, Raymond, Jones, & Griffiths, ). SDM developed for Antarctic benthic organisms are restricted to few case studies including deep‐sea shrimps (Basher & Costello, ), cirripeds (Gallego, Dennis, Basher, Lavery, & Sewell, ) and echinoids (Pierrat et al., ).…”

Using seabirds to map the distribution of elusive pelagic cephalopod species

“…A total of 11 squid species (n=22 individuals) were found in the diet of wandering albatrosses (Table I), complementing much of the known distribution of squid in the region. For instance, our study showed that Galiteuthis glacialis (n=8) can also be distributed in warmer and oceanic sub-Antarctic waters of the Argentine abyssal plain, as well as in Antarctic waters, bounded North by the Sub-Antarctic Front (SAF) (Xavier et al 2016). These results indicate a wider distribution range of G. glacialis towards northern latitudes, once oceanic fronts doesn't seem to limit their occurence, according to the existing distribution knowledge (Rodhouse et al 1987, Xavier et al 1999.…”

“…Many marine predators as fish (Patagonian toothfish Dissostichus eleginoides) or seabirds (albatrosses) were commonly used for study cephalopods occurence/distribution in Southern Ocean once they are eaten by higher predators, providing unique information about their ecology (Cherel & Weimerskirch 1995, Pilling 2001, Xavier et al 2002. Previous study has used wandering albatrosses Diomedea exulans as biological samplers to provide information about biogeography of oceanic prey, through probabilistic models based on satellite tracking and activity loggers data (Xavier et al 2006) and habitat suitability modelling (Xavier et al 2016).…”