| Abstract |
The abundance, distribution and species composition of cyclopoids were studied in the largest sardine fishing ground in the Philippines during a coastal upwelling event in March 2014. Zooplankton samples were collected in six stations along a transect extending from the coast to about 50 km offshore in Dipolog Bay, Northern Zamboanga Peninsula, Mindanao. A 100 脦录m NORPAC net was hauled vertically to sample successive depth strata (0芒聙聯65 m, 65芒聙聯135 m, 135芒聙聯200 m). Out of 28 zooplankton groups, cyclopoids made up 12.2 % of mean total zooplankton density. Forty-two cyclopoid species (overall mean density: 503.6 ind.m-3) were identified, with Oncaea clevei Fr脙录chtl, 1923 (25.4 %) as the most abundant, followed by Oncaea scottodicarloi Heron and Bradford-Grieve, 1995 (13.6 %), Triconia conifera (Giesbrecht, 1891) (9.2 %), Oncaea media Giesbrecht, 1891 (7.2 %) and Corycaeus dahli Tanaka, 1957 (7.0 %). The higher abundance (732.9 ind.m-3) of cyclopoids at 0芒聙聯65 m than at 135芒聙聯200 m (220.2 ind.m-3) was attributed to the high abundance of phytoplankton in the upper euphotic zone. Cyclopoid density was highest in station 4 (938.3 ind.m-3) at the margin of the upwelling zone. This is attributed to the time lag between phytoplankton and zooplankton build-up and the dispersive effects of wind-driven drift. |
Mindanao State
University - Iligan Institute of Technology