Abundance and spatial distribution of neustonic copepodits of Microsetella rosea along the western Magellan coast, southern Chile

• Published in: Latin american journal of aquatic research Vol. 44; no. 3; p. 576
• Main Authors: Canete, Juan I, Gallardo, Carlos S, Olave, Carlos, Romero, Maria S, Figueroa, Tania, Haro, Daniela
• Format: Journal Article
• Language: Spanish
• Published: Pontificia Universidad Catolica de Valparaiso, Escuela de Ciencias del Mar 01.07.2016
• Subjects: Chile
• ISSN: 0718-560X; 0718-560X
• DOI: 10.3856/vol44-issue3-fulltext-16

The pelagic harpacticoid copepod Microsetella rosea inhabits the cold waters along the temperate southern coast of Chile, where its population biology and ecological role in the neuston are unknown. During a CIMAR 16 Fiordos cruise realized in the Magellan Region, 26 neustonic samples were collected to analyze the abundance, spatial distribution of copepodits and oceanographic conditions (temperature, salinity, and dissolved oxygen). M. rosea copepodits, the most abundant holoneustonic taxa (30% of total abundance), were present at all sampled stations and were 0.5 times more abundant than calanoids. These copepodits inhabited waters ranging between 6.5-8.5[degrees]C and salinity of 26-33, with maximum abundances (1,000-10,000 ind/5 min horizontal drag) at means of 7.2 [+ or -] 0.6[degrees]C and salinities of 30.7 [+ or -] 0.9. Froward Cape, Almirantazgo Sound, and Inutil Bay stations accounted for 65% of total M. rosea abundance, whereas Beagle Channel stations present the lowest abundances (<4%). The entire sampling area was as an oxygenated estuary (7.4 [+ or -] 0.4 mL [L.sup.-1]). Given the abundance and recurrence of M. rosea in the Magellanic neuston, future research should assess the ecological functions of this species. Finally,M. rosea could also be used as a biotracer for processes of aggregation in other estuarine neustonic communities of southern Chile. Keywords: Microsetella rosea, Copepoda, neuston, subantarctic zooplankton, estuaries, oximax zone, southern Chile. El copepodo harpacticoide pelagico Microstella rosea habita las aguas frias a lo largo de la costa templada del sur de Chile, donde se desconoce su biologia poblacional y rol ecologico en el neuston. Durante el crucero CIMAR 16 Fiordos realizado en la region de Magallanes, se recolectaron 26 muestras neustonicas para analizar la abundancia, distribucion espacial de los copepoditos y condiciones oceanograficas (temperatura, salinidad y oxigeno disuelto). Los copepoditos de M. rosea, el taxa holoneustonico mas abundante (30%), se encontraron en todas las estaciones analizadas y fueron 0,5 veces mas abundantes que los copepodos calanoides. Los copepoditos habitaron aguas de 6.5-8.5[degrees]C, con salinidades de 26-33, con maximos de abundancia (1.00010.000 ind/5 min arrastre horizontal) con promedios de 7,2 [+ or -] 0,6[degrees]C y 30,7 [+ or -] 0,9 de salinidad. En las estaciones localizadas en Cabo Froward, Seno Almirantazgo y Bahia Inutil se colecto el 65% de la abundancia total de copepoditos; mientras que en las estaciones del Canal Beagle se registraron las menores abundancias (<4%). Toda el area de muestreo representa un estuario oxigenado (7,4 [+ or -] 0,4 mL [L.sup.-1]). Dada la abundancia y recurrencia de M. rosea en el neuston magallanico, se deberian efectuar futuras investigaciones para evaluar las funciones ecologicas de este copepodo. Finalmente, M. rosea podria ser utilizado como un biotrazador para procesos de agregacion en otras comunidades estuarinas neustonicas del sur de Chile. Palabras clave: Microsetella rosea, Copepoda, neuston, zooplancton subantarctico, estuarios, zonas Oximax, sur de Chile.