Growth, Mortality and Recruitment Pattern of Longsnouted Catfish, Arius argyropleuron (Valenciennes, 1840) in Kuala Muda and Merbok, Kedah

A study was conducted to investigate the growth parameters, mortality and recruitment pattern of longsnouted catfish, Arius argyropleuron collected at Kuala Muda and Merbok estuary fish landing site, northern part of Peninsular Malaysia. A. argyropleuron were collected from March 2009 to December 2009. The length-frequency data was analyzed using FAO-ICLARM Stock Assessment Tools (FiSAT) software. Bhattacharya’s plot produced  two groups of A. argyropleuron at modal length 11.13 ± 1.28 cm and 25.10 ± 2.32 cm. Population parameters were estimated by using various models including Powell-Wetherall plot, ELEFAN I , growth performance index, mortality estimation and recruitment pattern. Overall, growth parameters; asymptotic length (L?) = 34.26 cm and growth coefficient (K) = 0.7 year-1. Growth performance index (Ø’) = 2.915, total mortality (Z) = 2.56 year-1, natural mortality (M) = 1.39 year-1, fishing mortality (F) = 1.17 year-1 and exploitation rate (E) = 0.46 year-1. The length at first capture at 50%, (Lc) was 24.56 cm. The observation of the annual recruitment of A. argyropleuron was found to occur in two pulses in January and August. Keywords: Arius argyropleuron, growth, mortality, recruitment patter

Physical mechanism on the ASEAN Sea-Turtle Researcher Network

The paper refers that the signing of the Memorandum of Understanding (MoU) on ASEAN Sea Turtle Conservation and Protection by the ASEAN Ministers on Agriculture and Forestry in September 1997 indirectly provided the platform for the formation of a regional sea turtle researcher network. It was proposed that this network be named 'SEAFDEC-ASEAN Marine Turtle Conservation Network (SAMTCN)', and that the network should comprise turtle experts and non-experts alike. SAMTCN is expected to have a large group of followers

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

Assessment of Suitability of Kerian River Tributaries Using Length-weight Relationship and Relative Condition Factor of Six Freshwater Fish Species

The length-weight relationship and condition factor of six freshwater fish species were conducted monthly at selected rivers of Kerian River Basin from May 2008 to May 2009. The fish species studied were Devario regina, Labiobarbus sp., Puntius binotatus, Rasbora sumatrana, Acantopsis choironrhycos and Cyclocheilichthys apogon.  The value of fish growth (b) shows that D. regina (b = 3.256), P. binotatus (b = 3.911), R. sumatrana (b = 3.642) and C. apogon (b = 3.623) had positive allometric growth, while Labiobarbus sp. (b = 2.898) and A. choironrhycos (b = 2.427) had negative allometric growth. The mean Kn varied from 1.003 ± 0.109 (A. choirorhynchos) to 1.873 ± 0.203 (R. sumatrana). Of all the fish species, only mean Kn of R. sumatrana showed significant difference among the sampling sites, at P < 0.05, suggesting the fish growth in the Kerian River basin was in a good condition. Keywords: Length-weight relationship, condition factor, freshwater, Kerian River Basin, Malaysi

Distribution, abundance and biological studies of economically important fishes in the South China Sea, Area I: East coast of Peninsular Malaysia

This paper presents species distributions, composition and biological parameters of major fish species caught from the east coast of Peninsular Malaysia during the one week surveys made in pre- and post-Northeast monsoon seasons. The fish species rankings changed over time and at different depth strata. The catch rates were decreased toward deeper water. An appearance of smaller fish group was greater during the post-Northeast than pre-Northeast monsoon season. Fish populations occurred at both seasons were represented from different spawning group. Their growths were isometric form in weight

Length-weight Relationships of Some Important Estuarine Fish Species from Merbok Estuary, Kedah

Merbok estuary, located in the northern part of Peninsular Malaysia, was inhibited by 81 species that are representatives of 45 genera and 36 families of fish. The length-weight relationship of 23 fish species belonging to 18 families was presented. The b values varied between 2.7928 for Butis gymnopomus and 3.6001 for Sillago sihama. Nine species exhibited positive allometric growth, 10 species were negative allometric growth, 3 species had isometric growth and 1 species was Gompertz form of growth. The length-weight relationships for some species from the Merbok estuary are hereby publish for the first time, and most of the fish specimens were juveniles. Keywords: Estuarine fishes, length, weight, fisheries management, Merbok estuar

Population Dynamics of Tinfoil Barb, Barbonymus schwanenfeldii (Bleeker, 1853) in Pedu Reservoir, Kedah

The physico-chemical and biological parameters, species composition and population dynamic of dominant fish species were conducted in Pedu Reservoir in Kedah. The reservoir is considered safe from human activities, although the level of ammonia concentration (3.84 ± 2.65 mg/L) was exceeded the class recommended in Malaysia. 82.94% of fish families were contributed by Cyprinidae, 11.04% of Notopteridae, 3.01% of Bagridae and 2.51% for others. Twenty-four fish species were recorded in the reservoir and were dominated by Barbonymus schwanenfeldii (38.9%), followed by Oxygaster anomalura (12.4%) and Notopterus notopterus (11.0%). The length-weight relationships of B. schwanenfeldii was an isometric (b = 2.992) form with Kn ranging between 0.75 and 1.01. This fish could attain L? = 30.95 cm at growth rate of K = 0.66 yr-1, given the growth performance index (Ø’) of 2.801 that was represented from two cohorts occurred in August and February, respectively. The cohorts were strongly correlated to rainfall distribution in the area. The total mortality coefficient (Z) was 2.01 and natural mortality coefficient (M) was 1.37 yr-1 given the fishing mortality coefficient (F) and exploitation rate (E) was at 0.64 and 0.32 yr-1, respectively. The exploitation rate of 0.32 yr-1 was lower than the 75% of B’/R (E 0.1 = 0.41)  or optimum Y’/R (Emax = 0.53) indicating the yield per recruit of B. schwanenfeldii could be increased slightly by increasing the E. Keywords:  Barbonymus schwanenfeldii, length frequency, population parameters, management, Pedu Reservoir; Keda

Terrestrial insects as the main food for freshwater fish in Sungai Kerian tributaries: an implication on habitat conservation

The importance of terrestrial insects as food items for freshwater fish was studied by examining stomach contents of Devario regina (Fowler 1934) and its population parameters at canopied areas of selected tributaries of Sungai Kerian, in the northern state of Peninsular Malaysia. Ninety six percent (121 out of 126) of the fish stomachs examined contained food materials in the stomachs and the values of percentage of occurrence (%F), percentage numerical (%N) and percentage points (%P) indicated that collected fish ate similar food items in all rivers. Among the food categories, scavenging terrestrial ants (Formicidae) were the most dominant food item, hence the main diet for this species. The Index of Relative Importance (IRI) scores of food items indicated that ants were higher than other food items. This surface water feeder experienced a positive allometric growth (W = aLb) with a b (rate of growth) value of 3.256. Its asymptotic length, growth constant and growth performance index represented this species with a short life-span (L∞ = 10.90 cm, K = 1.20 year-1, φ’ = 2.15, tmax = 3 year, respectively) and had higher natural mortality (M = 2.40 year-1) than fishing mortality (F = 0.35 year-1) while the fish stock was underexploited (E = 0.13). The finding of this study indicated the importance of terrestrial ants as a food source that support excellent growth of D. regina and the need to conserve riparian trees along river banks to provide allocthonous materials and habitats for the ants