GROWTH AND REPRODUCTIVE BIOLOGY OF Amphiprion sebae FROM GULF OF MANNAR, SOUTHEAST COAST OF INDIA
Gulf of Mannar is one the important marine biodiversity hotspot bestowed with 115 beautifully colored marine ornamental fishes. Among them, anemone fishes belonging to the family Pomacentridae find prominent place in the marine ornamental fish trade. This paper helps to understand its growth character, mortality character and reproductive biology of A. sebae. This study was carried out for a period of one year from March 2016 to February 2017 at Ramanathapuram CeSA. The landed length ranged between 4.8 cm and 13.12 cm. They are omnivorous in nature and fecundity is moderate.
Biological studies of many species of the anemone fishes but Amphiprion sebae were available (Jaccquin, 1975; Bertschy, 1979: Britenstein, 1980). Fish specimens were collected from landing center bimonthly as well as from fish trap operated at five different places of Gulf of Mannar viz., Keelakari, Mandapam, Vallinokkam, Chinna Ervadi and Vembar to understand the biological characters of Amphiprion sebae. Food and feeding habits of these species were studied by using the method of the index of preponderance. Fecundity was also determined.
Five species of Amphiprion namely Amphiprion clarkii (Bennett, 1830), A. ocellaris (Cuvier, 1830), A. percula (Lacepède, 1802), A. polymnus (Linnaeus, 1758) and A. sebae (Bleeker, 1853) were landed during the study period. Joshi et al., (2016) recorded six species from this region. Of these, A. sebae is found to be higher and recorded frequency from nearshores upto the depth of 8 mts. They were reported to land throughout the year. Of the five landings centers observed, they were recorded to land at Keelakari, Mandapam, Vallinokkam and Chinna Ervadi.
Nearly 189 sebae clown were collected with the size ranged from 4.8 cm to 13.12 cm and the average size of 7.6 cm. The L∞ was 13.81 cm. Based on phi prime value (ø' = log10(K) + 2·log10(L¥) the growth co-efficient was estimated as 0.64 (Pauly and Munro, 1984). which is moderate. The growth estimate revealed that they reach a size of 4.92 cm during the end of first year and 13.85 at fifth year. Mostly matured animals were collected in pairs. The natural mortality was estimates as 1.65. Their food and feeding nature revealed they are omnivore and feeds mainly on crustaceans (38.2%) followed by molluscs (20%), filamentous algae (18.3%), coral polyp (15.5%) and unknown matter (8%).
Smallest testis bearing male was found to be 4.2cm. The ovary was first recorded at the size of 4.95 cm. Length at first maturity for female was estimated as 5.9 cm (Fig.1). Earlier recorded smaller matured female was 5.5cm (Pushbaraj, et al., 2010). Their fecundity was ranged between 724 to 1515 with the relationship of fecundity= 152.15 X - 201.18. where X= length of fish (cm). The clutch size was found to be higher than the earlier report of Boby Ignatius et al., 2001., and Dhaneesh et al., 2011. Two distinct ova diameter were observed. The smaller sized fishes are mostly found to be male. This species exhibit protandric hermaphrodite (Fricke and Fricke, 1977). where it can change its sex from male to female.
