Macrozoobenthos in the intertidal zone of the Ly Son island

The surveys of macrozoobenthos fauna of Ly Son tidal area were carried out at 8 stations in September 2016. The 4 replicate samples were collected in high, middle and low tidal zones at each station. The results record 92 taxa of mollusc (accounting for 35% of total number of taxa), 76 taxa of crustacean (29%), 71 taxa of polychaete (27%) and 22 taxa of echinoderm (9%). Among them, there are 7 species of valuable resources that were exploited for food such as sea cucumber (Holothuria (Semperothuria) cinerascens), collector urchin (Tripneustes gratilla), diadema urchin (Echinothrix diadema), Diadema savignyi (belonging to Echinoderma), strawberry conch (Strombus luhuanus), goldmouth turban (Turbo chrysostomus) and bearded horse mussel (Modiolus barbatus). Some species with beautiful shapes and colors are used for handycraft such as black-lip pearl oyster (Pinctada margaritifera), small giant clam (Tridacna maxima), Chinese cowrie (Cypraea chinensis)... The densities of mactozoobenthos vary from 38 to 1,632 individuals/m2 between stations and tend to increase from high to low tide zones; from sandy bottom and shore rock to dead coral habitats covered by seaweed and seagrass bed.

ASOSIASI DAN RELUNG MIKROHABITAT GASTROPODA PADA EKOSISTEM MANGROVE DI PULAU SIBU KECAMATAN OBA UTARA KOTA TIDORE KEPULAUAN PROVINSI MALUKU UTARA

Tujuan penelitian adalah untuk menganalisis asosiasi dan relung mikrohabitat gastropoda pada ekosistem hutan mangrove di Pulau Sibu Kecamatan Oba Utara Kota Tidore Kepulauan Provinsi Maluku Utara. Pengambilan sampel dilakukan pada saat air surut dengan menggunakan metode line transect. Hasil penelitian diperoleh komposisi jenis-jenis gastropoda di Pulau Donrotu sebanyak 12 jenis yaitu Littrorina scabra, Littorina undulata, Turbo agryrostoma, Turbo chrysostoma, Turbo breneus, Nerita costata, Nerita planospira, Strombus luhuanus,, Cerithiidea cingulata, Telescopium telescopium, Telebralia sulcata dan Terebralia palustris. Pasangan jenis gastropoda yang diperoleh memiliki tipe asosiasi positif sebanyak 14 pasangan, asosiasi negatif sebanyak 11 pasangan dan tidak ada asosiasi sebanyak 42 pasangan. Jenis gastropoda yang mempunyai relung habitat terlebar adalah Terebralia sulcata dan tersempit adalah Turbo chrysostomus.