Distribution and abundance of Oncaea media and O. venusta (Crustacea: Copepoda) in the colombian Pacific ocean during two periods in 2001

Abstract

Zooplankton of the Colombian Pacific Ocean was investigated during June-July (2001a) and August-September (2001b). Since Oncaea venusta and O. media predominated in the copepod community, their distribution and abundance were evaluated. Organisms were extracted from surface mesozooplankton samples taken with a conic net (50cm opening, 363µm mesh). Both species were widely distributed with highest abundances mainly in neritic waters (3°-5°N). Factor analysis revealed negative and positive correlations among abundances and abiotic variables depending on each period. Cluster analysis showed three groups in 2001a and five ones in 2001b, essentially consistent with night and day abundances, and thermocline depth and width suggesting the influence of these factors on O. venusta and O. media. In future analysis it may be necessary to consider the different forms of O. media and O. venusta to establish the importance of phytoplankton and other organisms in their diet. Higher night or day abundances allude to the possible diel vertical migration of these microcrustaceans to the surface. The decrease in the general abundance of O. venusta from 2001a to 2001b (66.4% to 47.5%) contrasted with the increase of O. media (33.6% to 52.5%). These changes could be explained by the different biological response of both species to short-term variability in oceanographic conditions and the occurrence of a weak La Niña event.

Composición y abundancia taxonómica del zooplancton desde el Pacífico Sur hasta la Península Antártica 2016-2017

“…This validates that this group is characterized by inhabiting the pelagic zone of all aquatic ecosystems in the world, where they can predominate in number and biomass, constituting between 60 and 80% of zooplankton (Campos and Suárez-Mórales, 1994;Boltovskoy, 1999). Therefore, their role in trophic plots and in the vertical flow of carbon is increasingly recognized (López and Mojica, 2015). Likewise, they are reported in studies carried out in the South Pole where the frequency of appearance of copepods in zooplanktonic samples is 100% (Bonicelli et al, 2008).…”

“…Las muestras fueron llevadas al laboratorio de la Universidad de Bogotá Jorge Tadeo Lozano, sede Santa Marta, donde se adelantó la limpieza de la totalidad de cada muestra. La separación, conteo e identificación de los Pacific (Monsalve, 1976;López, 2012;Pascal, 2012;Jaimes and López, 2013;López and Mojica, 2015;Medellín-Mora, 2016;Dorado-Roncancio, 2018). However, there are many factors that can directly or indirectly affect the density of these groups, either by physicochemical and/ or environmental factors or by interspecific competition within zooplankton with gelatinous organisms (salps) and/ or euphausiids that usually feed on copepods.…”

“…Los copépodos son probablemente los organismos más numerosos y diversos en los ambientes acuáticos, aportan la mayor biomasa entre el 40 y 98% de la densidad total del mesozooplancton en el Océano Pacífico suelen ser dominantes (Pakhomov et al, 2000;Bernard and Froneman, 2002;Cabal et al, 2002;López, 2012;Jaimes and López, 2013;López and Mojica, 2015;Dorado-Roncancio, 2018). The main families in Antarctica are represented by Oithonidae, Oncaeidae, Pseudocalanidae, Calanidae and Metridae (Cabal et al, 2002).…”

Revision and update of the checklist of copepods (Crustacea: Hexanauplia) of the Colombian Caribbean

“…A study on copepod feeding focussing on alimentarios de los copépopos, orientando su investigación hacia la especie Eucalanus subtenuis. De forma reciente, se han editado publicaciones sobre la distribución de los copépodos epipelágicos del Pacífico colombiano (López Mojica, 2015;Jerez-Guerrero et al, 2017).…”

“…the species Eucalanus subtenuis in the Colombian Caribbean was contributed by Franco-Herrera (2006). Recently, articles on distribution of epipelagic copepods from the Colombian Pacific were published (López and Mojica, 2015;Jérez-Guerrero et al, 2017).…”