Latitudinalandbathymetricpatternsinthedistributionandabundance of mesopelagicfishintheScotiaSea

Martin A. Collins (1, 2) , Gabriele Stowasser (1) , Sophie Fielding (1) , Rachel Shreeve (1) , José C. Xavier (3) , Hugh J. Venables (1) , Peter Enderlein (1) , Yves Cherel (4) , Anton van de Putte (5)

1 BAS - British Antarctic Survey
2 Oceanlab
3 Institut Marine Research
4 CEBC - Centre d'Études Biologiques de Chizé
5 Laboratory of Animal Diversity and Systematics

Mesopelagicfishareakeycomponentofthepelagicecosystemthroughouttheworld'soceans.Opening and closingnetswereusedtoinvestigatepatternsinthedistributionandabundanceofmesopelagic fish fromthesurfaceto1000monaseriesoftransectsacrosstheScotiaSeafromtheice-edgetothe AntarcticPolarFront.Atotalof141non-targetnethaulswereundertakenduringthreecruises(Nov 2006, Jan2008andMar2009),with7852teleostfishcaptured,representing43speciesin17families.A further 1517fishwerecaughtintargetednethauls.ThedominantfamiliesweretheMyctophidae (6961 specimens;21species)andBathylagidae(1467specimens;4species).Fewfishwerecaughtin the upper400mduringdaylight,whichwasattributedtoacombinationofnetavoidanceanddiurnal verticalmigration.Speciescompositionwaslinkedtodepthandlocationandwascloselyassociated with oceanographicfeatures.Diversitywaslowestincoldwateratthemostsoutherlystations,which were dominatedby Electronaantarctica, Gymnoscopelusbraueri and Bathylagusantarcticus. Further north,diversityincreasedwiththeadditionofspeciessuchas Krefftichthysanderssoni, Protomyctophum bolini and Electronacarlsbergi. Thedepthintegratedbiomassofmyctophidswassimilaracrossthe latitudinaltransectandproducedanestimateof4.5milliontonnesintheScotiaSea.Bathylagidswere patchily distributed,butwereabundantinthelowermesopelagiczone(4400 m)andarepotentially significantzooplanktonconsumers.Giventhebiomassofthemyctophidsandbathylagidscoupledwith the verticalmigrationsofmanyspecies,thesefisharelikelytoplayasignificantroleincarbonexport from thesurfacewaterstothedeepocean.

Mots clés: Myctophid; Myctophidae; Bathylagidae; Biomass; Southern Ocean

Domaines: Sciences de l'environnement

Martin A. Collins, Gabriele Stowasser, Sophie Fielding, Rachel Shreeve, José C. Xavier, et al.. Latitudinalandbathymetricpatternsinthedistributionandabundance of mesopelagicfishintheScotiaSea. Deep Sea Research, 2012, 59-60, pp.189-198. ⟨10.1016/j.dsr2.2011.07.003⟩. ⟨hal-00662416⟩