Biology of young grey mullet, Mugil cephalus L., populatioins in a coastal lagoon in Sri Lanka

Abstract

The biology of young grey mullet, Mugil cephalus L. populations of a coastal lagoon-the Negombo Lagoon on the West Coast of Sri Lanka was studied from October 1976 to March 1978. The relative abundance of fry were found to vary from month to month, with peaks occurring in December-January, May and September-October, coinciding with the end of rainy seasons. It was found that the young fry tended to migrate into the lagoon at a size of about 10-20 mm, most frequently between 15-20 mm in length, by which time they were fully scaled. The young fry after a period of growth in the shallow areas of the lagoon, when they reached a size of 30-35 mm, emigrated into the deeper waters of the lagoon.The rate of growth, as computed from length frequency distribution studies, was found to be around 0,24 mm day+. Results of diurnal surveys showed a movement of the larger size fry into shallower waters during the hours of darkness and this movement appears to be independent of the tidal cycle. It is postulated that the cause of this migration is to escape from predators, chiefly piscine. Investigations of the meristic characters indicated that the young fry which migrated into the lagoon at different times of the year probably originated from a single spawning stock.

Reproductive Biology of Keeled Fish <i>Liza Carinata</i> (Valenciennes, 1836) from Suez Bay, Egypt

“…K value in the present study not closely associated with the gonado -somatic index and this result may suggest that the reproduction does not influence fish condition. The condition factor of fishes has been reported to be influenced by a number of factors such as the onset of maturity, Spawning (De -Silva and Silva, 1979;Al-Daham and Wahab, 1991), sex and maturity (Gowda et al, 1987;Doddamani and Shanbouge, 2001) and Pollution (Bakhoum, 1999;Devi et al, 2008). During the present study also the monthly fluctuations in condition factor seemed to be influenced by gonadal development, availability of food and gastral activity.…”

Can Thin-lipped Mullet Directly Exploit the Primary and Detritic Production of European Macrotidal Salt Marshes?

“…Thus, their biology and ecology have often been studied in numerous environments (Thomson, 1966;Zisman et al, 1975;Collins, 1981;Al-Daham & Wahab, 1991). Although, an abundant literature focuses on various aspects of mullets' feeding habits (Odum, 1968;Albertini-Berhault, 1974;De Silva & Wijeyaratne, 1977;De Silva & Silva, 1979;De Silva, 1980), the available literature concerning feeding ecology of Liza ramada focuses on young stages (Albertini-Berhault, 1973, 1974, 1979Zismann et al, 1975;Ferrari & Chieregato, 1981) or in fish farming systems (Yashouv & Ben-Sachar, 1967;Cardona & Castello, 1994;Cardona, 1996). Only Hickling (1970), Almeida et al (1993), and Shapiro (1998) have studied the feeding habits of juveniles and adults in natural environments.…”

Determination of Morphometric Relationship and Condition Factors of Four Cichlids from Golinga Reservoir in Northern Region of Ghana

“…The condition factor of fishes has been reported to be influenced by a number of factors such as the onset of maturity (Hoda, 1987), spawning (De-Silva and Silva, 1979;Al-Daham and Wahab, 1991), sex and maturity (Gowda et al, 1987;Doddamani and Shanbouge, 2001) and pollution (Bakhoum, 1999;Devi et al, 2008). Condition factor is influenced by both biotic and abiotic environmental conditions and can be used as an index to assess the status of the aquatic ecosystem in which fish live (Anene, 2005).…”