Some Biological Aspects Of Gerres Filamentosus (Cuvier, 1829) In Merbok Estuary, Kedah, Peninsular Malaysia

Some biological aspects of Gerres filamentosus in Merbok estuary were studied from January to December 2011 using samples from monthly catches. Each sample consists of 50-100 fishes which varied from the smallest (10.1 cm) to the largest (18.3 cm) sizes. The length-weight relationship was analyzed for G. filamentosus by substituting the fish length and weight values into W=aLb. The calculated lengthweight relationships of W=0.011L3.154 and W=0.013L3.103 , obtained from female and male respectively. The exponent value, b = 3.154 for female and b = 3.103 for male showed that both male and female of G. filamentosus had positive allometric growth. Besides, the relative condition factor (Kn) obtained was 0.999±0.074SD and 1.002±0.080SD for female and male, had revealed that male had a better condition than female, at the same time proved that Merbok estuary was in good ambience for survival and favorable for this species. Moreover, the sex ratio was found to be 1:1.45 (male:female). The reproductive cycle of this species was analyzed using the gonadosomatic index, through macroscopic observation and histological method. The maturity stages of male and female G.filamentosus were classified into four stages of testes and five stages of ovary. Herein, G. filamentosus spawn throughout the year with two spawning peaks, one in October 2011 and the second one in February 2011, which coincided with the primary maximum (September to November) and primary minimum (January to February) of rainfall

Population Parameters, Feeding And Reproductive Biology Of Rasbora Spp. From The Streams Of Muda Reservoir, Kedah, Malaysia

A study on the biological aspects of the Rasbora spp. was carried out in five chosen streams of Muda Reservoir for duration of 12 months from November 2014 until October 2015. This study includes the determination of water quality parameters and fish composition, length-weight relationship, relative condition factor, population parameters and feeding biology of R. dusonensis and R. vulgaris, and reproductive biology of R. dusonensis

Reproductive biology of estuarine catfish, Arius argyropleuron (Siluriformes: Ariidae) in the northern part of Peninsular Malaysia

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 biolog