Alienvs.Predator: interactions between the colossal squid (Mesonychoteuthis hamiltoni) and the Antarctic toothfish (Dissostichus mawsoni)

Abstract

Data collected onboard two South Korean longliners in 2011-2014 targeting Antarctic toothfish provided insights into trophic interactions between two Antarctic top predators: the colossal squid Mesonychoteuthis hamiltoni and the Antarctic toothfish Dissostichus mawsoni. Adults of each species opportunistically prey upon weakened representatives of the other species: squid will feed on longlinecaught toothfish, and toothfish on dying and dead squid. The highest occurrence of squid attacks was recorded in the Davis Sea and Commonwealth Sea, and the lowest in the Ross Sea. Squid depredation rates were around 1% on average, though regionally they might rise to 2-3%, which is of a similar magnitude to rates caused by sperm whales and killer whales in some areas.

Understanding the Interactions Between Cetaceans and Other Megafauna With the Albacore Tuna Fishery: A Case Study From the Cyprus’ Pelagic Longline Fishery

“…The blue shark, the shortfin mako and the bigeye thresher (Alopias superciliosus) are the most commonly bycaught shark species in the Cypriot pelagic longline fishery (Department of Fisheries andMarine Research 2016 -2021). The very limited published information on squid depredation mentioned the depredation by the colossal squid (Mesonychoteuthis hamiltoni) on longlines targeting the Antarctic toothfish in the Southern Ocean (Remeslo et al, 2015) and by the purpleback flying squid (Sthenoteuthis oualaniensis) on gillnets targeting tuna in the Northern Arabian Sea (Moazzam, 2019). However, squid depredation has never been reported before in the Mediterranean fisheries.…”

Towards unlocking the trophic roles of rarely encountered squid: Opportunistic samples of Taningia danae and a Chiroteuthis aff. veranii reveal that the Southern Ocean top predators are nutrient links connecting deep-sea and shelf-slope environments

“…The GAB squids with high d 15 N values were at the second highest trophic level, just below the colossal squid Mesonychoteuthis hamiltoni from the Southern Ocean. Mesonychoteuthis hamiltoni is the heaviest known invertebrate (Rosa et al, 2017) and is thought to consume Antarctic toothfish (Dissostichus mawsoni, Remeslo et al, 2015), which, in turn, are high-trophic-level predators of mid-to largesized cephalopods and fishes (Queiroś et al, 2021). Additionally, the similarities between the GAB squid FAs and FA profiles from other large, actively predatory squid species including giant squid Architeuthis dux, Antarctic flying squid Todarodes filippovae, flying squid Ommastrephes bartramii, whiplash squid Idioteuthis cordiformis, and arrow squid Nototodarus gouldi suggest roles as active pelagic predators.…”

Cephalopod fauna of the Pacific Southern Ocean using Antarctic toothfish (Dissostichus mawsoni) as biological samplers and fisheries bycatch specimens

“…Moroteuthopsis longimana and Psychroteuthis glacialis, and octopuses, e.g. Pareledone turqueti and Stauroteuthis gilchristi (Collins et al, 2007;Fenaughty et al, 2003;Jo et al, 2013;Remeslo et al, 2015;Roberts et al, 2011;Stevens et al, 2014;Yoon et al, 2017). The Antarctic toothfish, like its close relative the Patagonian toothfish Dissostichus eleginoides, can be found down to depths of c. 2,200 m and it is a sedentary species with individuals not moving between areas in a short time period (Hanchet et al, 2008(Hanchet et al, , 2015.…”