ON THE BIOLOGY AND BASIC CHARACTERISTICS OF THE POPULATION DYNAMIC OF THE DOG CONCH, STROMBUS CANARIUM LINNAEUS, 1758 (STROMBIDAE) - Zaidi Che Cob; Aziz Arshad; Japar Sidik Bujang; Mazlan Abd. Ghaffar (Tropical Life Sciences Research, 2008)
Strombus canarium Linnaeus, 1758 is among the important gastropod fishery within the western Johor Straits, Malaysia. In this study, systematic random samplings using belt transect were conducted from January to December 2005. Shell-length data were grouped into different sexes and length-classes of 2 mm intervals. Overall ratio of males to females was 1:1.73, which was not significantly deviated from the expected 1:1 (P > 0.05). The population structure was analyzed using the Length-based Fish Stock Assessment (LFSA) protocol in FiSAT (FAO-ICLARM Stock Assessment Tools) software package. Both males and females were highly polymodal in monthly length-frequency distributions. Sexual dimorphism was evident within the population. Specific cohort growth parameters found higher asymptotic length (L?) and growth constant (K) in females compared to the males. The mean L? was 62.90 ± 3.68 mm in males and 69.73 ± 0.80 mm in females, while the mean K was 1.10 ± 0.15 yr–1 in males and 1.40 ± 0.10 yr–1 in females. The higher growth rates and faster growth to marketable size, combined with all year round recruitment indicated great potential for introduction into aquaculture. However, further studies are greatly needed in assessing actual growth and other parameters of this important gastropod species. Strombus canarium Linnaeus, 1758 merupakan antara sumber perikanan gastropoda paling utama di perairan Selat Johor, Malaysia. Dalam kajian ini, persampelan dilakukan secara rawak menggunakan kaedah jalur transek, bermula dari Januari hingga Disember 2005. Data panjang cangkerang dibahagikan mengikut jantina dan panjang, dengan sela-kelas 2 mm. Secara keseluruhannya, nisbah jantan kepada betina adalah pada kadar 1:1.73, yang tidak berbeza secara signifikan berbanding nisbah yang dijangka iaitu 1:1 (P > 0.05). Struktur populasi dianalisis menggunakan kaedah 'Length-based Fish Stock Assessment' (LFSA) yang terdapat dalam perisian FiSAT (FAO-ICLARM Stock Assessment Tools). Taburan panjang-berat bulanan kedua-dua subpopulasi siput jantan dan betina bersifat polimodal. Populasi juga didapati menunjukkan ciri-ciri dwimorfisma jantina. Parameter tumbesaran spesifik bagi setiap kohot menunjukkan nilai panjang 'asimptotik' (L?) dan pemalar tumbesaran (K) yang lebih tinggi bagi siput betina berbanding siput jantan. Nilai min L? adalah 62.90 ± 3.68 mm bagi jantan dan 69.73 ± 0.80 mm bagi betina, sementara nilai min K adalah 1.10 ± 0.15/thn bagi jantan dan 1.40 ± 0.10/thn bagi betina. Kadar tumbesaran yang tinggi dan masa bagi mencapai saiz pasaran yang cepat, ditambah dengan keupayaan untuk membiak sepanjang tahun menjadikan siput ini berpotensi besar bagi aktiviti akuakultur. Walau bagaimanapun, kajian lanjut diperlukan dalam menilai kadar tumbesaran sebenar, serta beberapa parameter lain yang penting bagi sesuatu spesies sebelum sebarang tindakan pengkomersialan dapat dilakukan.