Gelatinous zooplankton (ctenophores, salps and medusae): an important food resource of fishes in temperate SW Atlantic Ocean.

DIAZ BRIZ L.; SANCHEZ; MARI N.; MIANZAN H.; GENZANO G. N.

MARINE BIOLOGY RESEARCH

TAYLOR & FRANCIS AS

Lugar: Londres; Año: 2017

1745-1000

This study quantifies the occurrence of gelatinous zooplankton in the stomach contents offishes from the southwest Atlantic Ocean (33°?55°S). More than 69,000 fish stomachsbelonging to 107 species were examined. A total of 39 fishes were documented asconsumers of gelatinous zooplankton, 23 of which were newly discovered. Three gelatinousorganism consumption categories are recognized: (1) very frequent consumers (10 species,six of which were exclusive); frequent consumers (five species); and occasional consumers(26 species). Three types of gelatinous prey (ctenophores, salps and medusae) were found inthe stomach contents of fishes. Ctenophores were consumed at high levels across almost theentire continental shelves of Argentina and Uruguay. Salps were frequent prey on the slopeand southern shelf. In contrast, medusae were consumed in coastal areas, slopes and thesouthern shelf. Classification methods (group average sorting of the Bray?Curtis similaritymeasures based on log (X + 1)-transformed percentage data) determined six areas wherefishes predated on gelatinous organisms. SIMPER (similarity percentages) analysis determinedwhich fishes contributed more to the consumption of gelatinous organisms. Results revealedthat two fish species (Stromateus brasiliensis and Squalus acanthias) had high gelatinouszooplankton predation rates throughout the entire study area, while another six species(Patagonotothen ramsayi, Helicolenus dactylopterus lahillei, Macrourus holotrachys, Merlucciushubbsi, Schroederichthys bivius, and Macruronus magellanicus), while widely distributed,seemed to have specific areas where consumption occurred. This study not only providesnew knowledge about the importance of gelatinous zooplankton in the diet of numerousfishes, but might also be valuable for planning and managing local fisheries.