Asian Journal of Fisheries and Aquatic Research

Gillnet is a wall of netting that hangs in the water column, typically made of monofilament or multifilament nylon, had the same size and usually used by fisherman in Pangandaran. This research aims to see the capture process of white pomfret (Pampus argenteus) on gillnet in Pangandaran Regency. This research was conducted in August 2018 and January 2019 in Pangandaran. The data used in this research are primary data consisting of the proportion of catches and capture process, whereas secondary data obtained from Dinas Perikanan Pangandaran. The results of this research show that the quantity and weight proportion of main catch > bycatch and captured process of white pomfret dominated by wedged by 94% and the lowest is gilled by 6%.

White pomfret (Pampus argenteus) is one of the economically important fish and includes the leading commodity in Pangandaran Waters. Information on fishing biology of those species were still limited. The purpose of this study is to determine stock estimates including length-weight relationship, age group, growth, mortality and exploitation rate of white pomfret. Monthly length-frequency data have been collected from November 2018 to August 2019 at Cikidang fish auction. Fish length-frequency distribution was separated into a normal distribution using the Bhattacharya method with software of FiSAT (FAO-ICLARM Stock Assessment Tools). Estimation of population parameters used analytical model application with ELEFAN-1 (Electronic Length Frequency Analysis) program. The results showed that lengths distribution of white pomfret ranged between 19.3 cm - 36.8 cmTL. Length-weight relations was negatively allometric (W = 0,1184L^2,3719). Growth equation of white pomfret is Lt = 53.04 (1-e^-0.26(t)). Natural mortality (M) was 0.60/year, fishing mortality (F) was 3.04/year and total mortality (Z) was 3.64/ year. The exploitation rate (E) was 0.84. It is mean that higher than optimal exploitation so that the white pomfret fish population in a state of overfished. It is necessary to better policy in the management of white pomfret through precaution approach and describing of biological and fishing aspect in Pangandaran Waters.

The microbial communities of culture water and catfish C. gariepinus from three replicates of earthen, concrete and tarpaulin ponds in Nigeria were analyzed. Waters was collected from 25 cm below pond water surface per culture system. Three catfish per replicate system were also collected and analyzed in the lab. Catfish gut, skin and gills were analyzed. Earthen ponds had significantly more diverse microbial community and coliform forming units (CFU/ml) 2.43 x10^-4 CFU/ml than the rest systems. Earthen ponds had consortium of Klebsiella pneumonia, S. aureus and Salmonella enteritidis and E. coli, which was more diverse than all other aquaculture systems.  Microbiota of tarpaulin ponds was 2.10x10^-4 /ml CFU and this was significantly (P<0.05) higher than concrete ponds (1.50x10^-4 CFU/ml). Tarpaulin ponds had K. pneumoniae and E. coli, while concrete pond had S. aureus and S. enteritidis. Biofilm formation could have lead to colonization of the fish body part. The skin and gills had similar microbiota as the culture water compared to the gut. The gut microbial communities were not synonymous with the culture water.

The dietary effect Tiger nut (Cyperus esculentus) seed powder was examined on the egg and milt quality of African catfish broodstock.45 Female catfish broodstock of average body weight, 475 ± 25.00g and male catfish broodstock of average body weight, 487.09±13.57 g. Five diets with crude protein of 40% were formulated with different inclusion levels of Cyperus esculentus seed powder; 0, 0.5, 1.0, 1.5, 2.0 g per 100 g of experimental diet (D₁, D₂ ,D₃, D₄ and D₅). The experiment was carried out for 70 days and fish fed twice daily at 3% body weight. Fish fed experimental diets showed significantly improved growth performance and reproductive indices over the control treatment. Fish fed D₃ had the highest weight gain (173.6±10.98) in female catfish while D₅ had highest weight gain (215.17±11.62) in male catfish. Fish fed with D₄ had the highest percentage fertilization (93.00±3.05) and percentage hatchability (85.00±2.64) in female catfish while in male catfish the highest percentage fertilization (94.00±1.29) and hatchability (79.17±10.09) was from D₅. Percentage survival and gonadosomatic index was higher in fish fed D₅ in both female and male catfish. Histology of fish fed with Cyperus esculentus diets revealed oocytes formation within the ovaries. Ovary of fish fed D1 showed primary oocytes, with primary yolk accumulation in the ovary of fish fed D₂ and there were improvement in the oocytes. Fish fed D₃, D₄ and D₅ showed more matured oocytes and ripe yolk of late maturing stage. There was reduced seminiferous tubular lumen and scanty spermatozoa in D₁ and D₂ and there was high spermatozoa density in the seminiferous lumen seen in the testicular histology of fish fed diets D₃, D₄ and D₅. This result revealed that dietary inclusion of Cyperus esculentus seed powder enhance growth and improves fertility in Clarias gariepinus which will improve the quantitiy of its seed production.

Heavy metals are elements that contaminate seafood and make them harmful to human health when present in quantities that are higher than the permissible limit. This study was conducted to determine some heavy metals such as lead and mercury contained in dried crayfish gotten from three different locations (Oron, Ataba and Nembe town in Akwa Ibom, Rivers and Bayelsa State respectively) and sold in the Creek Road Market, Borokiri, Port Harcourt, Rivers State. The dried crayfish samples were purchased randomly from marketers in the market. 5g of the dried crayfish samples with its different organs (Gills, muscle tissues) were ground into powdered form and digested with HNO₃  using standard procedures   and analysed for lead and mercury using the micro plasma atomic emission spectrophotometric analyser. The results showed that Lead content in the dried crayfish from Oron, Ataba and Nembe were 0.140 ± 0.014 mg/kg, 0.040 ± 0.014 mg/kg and 0.016 ± 0.002 mg/kg respectively while for Mercury content, Oron crayfish contained 5.136 ± 0.017 mg/kg, Ataba 3.744 ± 0.017 mg/kg and Nembe 3.948 ± 0.023mg/kg. The mean values in the three different crayfish samples were significantly different (p<0.05). This result shows that the lead content present in the dried crayfish are within the permissible limit of 1 mg/kg as indicated by FAO hence safe for consumption purposes with no expected form of toxicity and health implication to consumers whereas for mercury content, the level was found to be above the permissible limit.