Zoological Studies

Vol. 50 No. 6, 2011

Feeding Ecology of Acetes intermedius Omori 1975 (Crustacea, Decapoda, Sergestidae) in Iligan Bay, the Philippines

Ephrime B. Metillo

Department of Biological Sciences, Mindanao State Univ.-Iligan Institute of Technology, Andres Bonifacio Ave., Iligan City 9200, the Philippines

Ephrime B. Metillo (2011) A multivariate analysis of stomach contents was used to investigate the trophic ecology of nighttime-collected Acetes intermedius in 2 adjacent near-shore estuaries in Iligan Bay, northern Mindanao, the Philippines from Feb. 1999 to Jan. 2000. Thirteen diet categories were observed indicating that A. intermedius is an omnivorous zooplanktivore with copepods, ostracods, decapod crustacean larvae, gastropod and bivalve veligers, and amorphous materials as dominant food items. Juveniles, however, showed a predominance of amorphous and fine materials. A linear ordination redundancy analysis showed that peak abundances of different dietary items coincided with monthly rainfall and sea surface temperature. The most common prey item of copepod fragments dominated in Mar. to June, months with high rainfall and warmer seas. Other common prey items, ostracods, bivalve and gastropod veligers, decapod crustacean fragments, chaetognaths, and tintinnids were correlated with cooler months from July to Nov. Peaks of most common ingested prey items were associated with dominance of equivalent zooplankton categories. The present study demonstrates that this species occupies an environmentally cued omnivorous feeding niche between lower-trophic-level plankton, particularly mesozooplankton, and higher predators in the pelagic zone of Iligan Bay.

Key words: Acetes intermedius, Trophic ecology, Multivariate analysis.

*Correspondence: Tel: 63-221-4068. E-mail:ephrime.metillo@g.msuiit.edu.ph