Predicting habitat use by the Argentine hake Merluccius hubbsi in a warmer world: inferences from the Middle Holocene

GREEN ELEANOR JOAN; ÁLVAREZ, MYRIAN; SALEMME MÓNICA; SPELLER CAMILLA; CARDONA LUIS; BAS LÓPEZ MARÍA; SANTIAGO FERNANDO; BRIZ I GODINO IVAN

Barcelona

Simposio; VII International Symposium on Marine Sciences; 2020

Universitat de Barcelona

Fish skeletal remains recovered from two archaeological sites dated in theMiddle Holocene of Tierra del Fuego (Argentina) were analysed to describe habitat usepatterns by hake in the past and predict changes in a warmer world. Mitochondrial DNAwas successfully extracted and amplified from 42 out of 45 first vertebra from ancienthake and phylogenetic analysis assigned all haplotypes to Argentine hake (Merlucciushubbsi). According to osteometry, the Argentine hake recovered from the archaeologicalsite were likely adults ranging 37.2 to 58.1 cm in standard length. C and N stable isotopeanalysis showed that currently Argentine hake use foraging grounds deeper than those ofPatagonian blenny and pink cusk-eel. Argentine hake, however, had a much broaderisotopic niche during the Middle Holocene, when a large part of the population foragedmuch shallower than contemporary pink cusk-eel. The overall evidence suggests thepresence of large numbers of Argentine hake onshore Tierra del Fuego during the MiddleHolocene, which allowed exploitation by hunter-gatherer-fisher groups devoid of fishingtechnology. Interestingly, average SST off Tierra del Fuego during the Middle Holocenewas higher than currently (11ºC vs 7ºC) and matched SST in the current southernmostonshore spawning aggregations, at latitude 47ºS. This indicates that increasing SSTresulting from global warming will likely result into an increased abundance of adultArgentine hake onshore Tierra del Fuego, as during the Middle Holocene. Furthermore,stable isotope ratios from mollusc shells confirmed a much higher marine primaryproductivity during the Middle Holocene off Tierra del Fuego.