Journal of Biology, Agriculture and Healthcare www.iiste.org ISSN 2224-3208 (Paper) ISSN 2225-093X (Online) Vol 2, No.3, 2012 14 Reproductive biology of estuarine catfish, Arius argyropleuron (Siluriformes: Ariidae) in the northern part of Peninsular Malaysia Mansor Mat Isa 1,2* Nurul Shafikah Mohd Noor 1 Khairun Yahya 1,2 , Siti Azizah Md Nor 1,2 1. School of biological Sciences, Universiti Sains Malaysia, Minden, 11800, Penang, MALAYSIA. 2. Centre for Marine and Coastal Studies, USM, Muka Head, 11060, Teluk Bahang, Penang, MALAYSIA. * E-mail of the corresponding author: drmansor@usm.my Abstract A preliminary study on reproductive biology of estuarine catfish, Arius argyropleuron was conducted using samples collected from Merbok estuary which is located in the northern part of peninsular Malaysia. The fish samples were collected in March-December 2009 using a barrier nets deployed on mudflat opposite vegetation of mangroves. Testes and ovaries were classified base on volume relative to abdominal cavity, gonad forms, size of gonad, colors and oocytes diameter. The gonado-somatic indices showed that the fish matured throughout the year with major spawning peak for females occurred in April and minor peak in July, whereas males recorded a higher peak in November. Absolute fecundity of mature ovary was ranged from 19 to 87 eggs and was linearly related to fish length and power function to fish body weight. Three groups of eggs for the ovary in stage II and two groups in stage III were recorded. The length at first maturity for both males and females was approximately 22.5 cm in fork length. Keywords: Arius argyropleuron, Merbok estuary, peninsular Malaysia, reproductive biology 1. Introduction Genera of Ariidea are widely distributed in temperate and tropical areas, both in coastal and estuaries (Marceniuk & Menezes 2007). Arius argyropleuron is one of the species widely found in Indo-West Pacific; East coast and eastern coastal India, Thailand, Indonesia, Malaysia, the Philippines, southern coast of New Guinea and the north coast of Australia (Kailola 1999, 2000). In Malaysia this species is commonly abundant in shallow, muddy coastal and estuary areas (Gambang & Khiok 2005, Mohsin & Ambak 1996, Ambak et al. 2010). They contribute to the socio-economics of the artisanal fisheries and are normally caught by gill nets, trammel nets and barrier nets; this fish is being marketed directly when caught, dried and salted (Mansor et al. 1998). The fish eggs are quite large and can be sold for RM15-RM20 per kilogram (approximately USD4.60-6.30).