Remoción del dinoflagelado tóxico Alexandrium tamarense (Dinophyta, Gonyaulacales) por Mnemiopsis leidyi (Ctenophora, Lobata) en condiciones experimentales controladas

The objective of the present study is to estimate the removal capability of the ctenophore Mnemiopsis leidyi (Ctenophora, Lobata) on cultures of the toxic dinoflagellate Alexandrium tamarense (Dinophyta, Gonyaulacales). For this purpose, observations on its clearance and survival rates were made in controlled experiments, using different A. tamarense cell concentrations. Mnemiopsis leidyi is able to remove dinoflagellates actively from the water column only at the lowest density tested (150 cells mL-1). Animals exposed to 300 cells mL-1 presented negative clearance and removal rates (survival= 67%). All ctenophores exposed at the highest concentrations of toxic dinoflagellates (600 cells mL-1) died after 4 h. Removal may occur mainly by incorporating and entangling cells in the mucus strands formed by the ctenophore, and in a lesser way by ingestion. Results indicate that higher concentrations of A. tamarense are fatally toxic to M. leidyi and that this ctenophore could control only the initial development of this dinoflagellate bloom.Fil: Bolasina, Sergio Nestor. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Universidade Federal do Rio de Janeiro; BrasilFil: Benavidez, Hugo. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Montoya, Nora Gladys. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Carreto Iraurgui, Jose Ignacio. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Acha, Eduardo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; ArgentinaFil: Mianzan, Hermes Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentin