Ecology, Environment and Conservation Paper

ABUNDANCE AND COMPOSITION OF POTENTIAL FOOD ITEMS OF WHALE SHARK (RHINCODON TYPUS SMITH, 1828) IN PROBOLINGGO WATERS, EAST JAVA PROVINCE

Mohammad Mukhlis Kamal, Diena Ardania and M Tri Hartanto

Abstract

Whale sharks (Rhincodon typus) appears seasonally in Probolinggo waters from January to May, where its main aggregation situated in Bentar Beach, Madura Strait. The question needs to be resolved is which factors affecting whale shark’s arrival. Therefore, the research was aimed to compare the potential food items by comparing the conditions with and without whale shark represented by March and August 2017. Planktons were collected by bongo-net with 60 cm mouth opening and 350 μm mesh-size, tied to 30 m nylon rope and pulled by the boat at 2-3 knot speed for 10 min for each. Sample was preserved with 4% formaldehyde, and in laboratory, 1 mL sample was placed into Sedgwick-Rafter Counting Chamber and identified by light microscope. Abundance is calculated by taking into account the volume of filtered water, volume of screened water, and individual number of each taxon. Correlation between food items and whale shark appearance was tested by Spearman rank correlation. The results confirm that copepoda, crustacea, and fish larvae were the principal diets for whale shark. A direct effect of chlorophyll a on zooplankton hence whale shark arrival was unconfirmed.