RETNO HARTATI*, MUHAMMAD ZAINURI, AMBARIYANTO AMBARIYANTO, WIDIANINGSIH WIDIANINGSIH, EDY SUPRIYO AND AGOES SOEGIANTO,**
Department of Marine Science, Faculty of Fisheries and Marine Science, Universitas Diponegoro, Jl. Prof. Dr. Soedharto, SH. Kampus Tembalang, Semarang 50275, Indonesia
*(e-mail : retnohartati.undip@yahoo.com, Mobile: +628112912299; **agoes_soegianto@unair.ac.id; Mobile:
+6281335733862)
ABSTRACT
The organic matter, chlorophyll and grain size features of the sediment in sea pens Holothuria atra cultivated in Jepara Waters, Indonesia were characterized. The study was undertaken in three 25 m2 sea pens where the sea cucumbers were stocked at 3 indiduals/m2 and reared for five months. The 3 cm upper layer of the surface sediment where H. atra feeded inside sea pens was sampled and measured for organic matter and analyzed for chlorophyll-a, -b and -c. Sediment samples of 100 g from sea pens were also taken, sieved and weighed to determine their grain size composition. The results showed that the organic matter, chlorophyll as well as the concentration of sands, fine sands and silts in the sediments fluctuated along the H. atra cultured period. As deposit feeding, H. atra digested and utilized the organic component removed from the sediment. Chlorophyll-a, -b and -c value as representative of
microphytobenthos in the sediment which were also source of nutrient needed for H. atra growth and survival were decreased in the end of experiments. Among the grain properties, the silt contents tended
to increase and showed the utilization of sediment by H. atra.
Key words : Grain size, habitat, Jepara Indonesia, microphytobenthic, sea cucumber