Global seafood demand has continued to rise amidst challenges to traditional aquaculture operations.Current shrimp aquaculture practice requires high water exchange and discharges toxic effluent to the environment.Bio...Global seafood demand has continued to rise amidst challenges to traditional aquaculture operations.Current shrimp aquaculture practice requires high water exchange and discharges toxic effluent to the environment.Biofloc technology(BFT)is self-sustaining and emphasizes nutrient cycling through microbial activity to maintain water quality.The effect of BFT on water quality and profitability of shrimp(Litopenaeus vannamei)culture was determined over a 70-day period.Ponds P1,P2,and P3 were treated with BFT and compared to a control group(P4)without BFT.Bacillus infantis cultured inoculum initiated biofloc development while molasses-maintained C:N ratio of 15:1.One-way ANOVA determined the mean differences in Temperature,pH,dissolved oxygen(DO),total dissolved solid,alkalinity,salinity,ammonia(NH_(3)),nitrates,nitrites(NO_(2)^(-)),calcium,magnesium,as well as shrimp body weight(BW)and total length(TL)across treatments.Profitability was determined by comparing the cost of production with sales and plotting it on a bar chart.BFT shrimp exhibited significantly higher BW(13.6 g)compared to 8.1 g in the control,and maintained a higher survival rate(80–90%)by day 70.Water quality was better managed in BFT,with NH_(3) consistently kept below 0.5mg/L;transient peaks of NO_(2)^(-),more stable pH(averaging at 7.5),and better DO management,maintained above 5 mg/L.BFT provided higher profitability of Ringgit Malaysia(RM)11,019.67(P1)and RM 8651.83(P2)compared to financiallosses in the non-biofloc system.Although operational challenges were reported,BFT showed superior resilience,suggesting that proper technical training and farm management are crucial for its optimization.展开更多
This work’s goal was to compile a list of fishing-related violations in order to suggest ways to enhance the surveillance system.In order to accomplish this goal,the following approach was used:Executive consultation...This work’s goal was to compile a list of fishing-related violations in order to suggest ways to enhance the surveillance system.In order to accomplish this goal,the following approach was used:Executive consultation and archive exploitation;surveillance agent survey;surveillance system identification and description;identification of offenses and fleet involved in the Guinean exclusive and economic area in recent years;identification and categorization of offense causes;surveillance system evaluation;and suggestion for enhanced surveillance system measures.Monitoring of this strategy showed that:fishing operating zones,administrative paperwork,and fishing gear are all linked to the infractions committed in the Guinean exclusive and economic zone.Records show that there were 308 boardings between 2006 and 2021.IP(Intellectual Property)infringement rates are 59%,Motorized Artisanal Fishing is 25%,and Semi-industrial fishing is 16%.In Motorized Artisanal Fishing,the Guineans have committed 33,the Senegalese have committed 23,and the Leonese have committed 18.In Semi-industrial fishing,the Chinese have committed 17 and the Senegalese have committed 16.According to the stakeholder survey,Vessal Monitoring System monitored 79 vessels in industrial fishing and 49 in Semi-industrial fishing in 2021.Registration certificates,personnel,rescue gear,gross tonnage,coastal state fishing authority,and maritime radio license are typically the primary documents examined at sea.From 2006 to 2022,a total of 135 fleets-80 demersal trawlers,7 cephalopod boats,21 shrimp boats,22 pelagic trawlers,and 5 cargo ships-were implicated in violations in the Guinean exclusive and economic area.By integrating the automatic identification system and Vessal Monitoring systems for fisheries surveillance,establishing a marking system for fishing gear,investing in highly effective launches,and protecting the privacy of patrol activities,Guinea’s surveillance system might be improved more effectively.展开更多
Humans have always engaged with their surroundings and the ecology in which they live.However,during the industrial age,this contact has been more intense and has had a substantial impact on environment and ecosystems...Humans have always engaged with their surroundings and the ecology in which they live.However,during the industrial age,this contact has been more intense and has had a substantial impact on environment and ecosystems.For example,overexploitation of natural resources,mining,pollution,and deforestation are all elements that negatively affect biodiversity and natural resources.Few studies have been conducted to evaluate the damage caused,despite the significant uncontrolled pressure from human activity.However,maintaining its environment is essential to the survival of coastal fishing.Goal:This study’s goal was to evaluate how human activity affected Tabounsou’s coastal ecology in order to suggest remedial actions for sustainable management.The following was the methodological approach used:executive consultation and archival analysis;stakeholder survey(locals,farmers,salt producers,fishers,and loggers);inventory of species;anthropogenic activity inventory;evaluation of how human activity affects aquatic life in the research region;suggestion and action for sustainable management;Outcome:Executive consultation indicated that the main issues are:construction projects that reduce the estuary’s surface area;agricultural practices such as woodcutting and salt farming;the rise in resource exploitation;noncompliance with fisheries laws;and the catching of young fish.Eighty-three percent of fisherman ditch their nets on the coast after using them,but only seventeen percent burn them.With a 75%frequency rate,the same survey indicates that most fisherman fish around the coast.In the Tabounsou area,according to loggers’survey,68%of the wood cut is Rhizophora,24%is Avicennia,and 8%is Laguncularia.Three fish stocks,representing nine families and nine species,were identified by the species inventory.At 18%and 15%,respectively,the actors most frequently capture the species Pseudotolithus elongatus and Arius parkii.According to a poll of 30 farmers,90%of them apply fertilizer to their soil,while only 10%do not.During the dry season,salt is grown.According to two actors,Bougna Toro Toro produces 100 kg of salt per day,followed by Khoumawadé,which produces 80 kg,and Toumbibougni,which produces 70 kg.展开更多
Chitin was first discovered by its name from the Greek word“chiton”,which means“mail coat”.It is indeed a polysaccharide made up of naturally occurring acetyl-D-glucosamine monomers.Hatchett was the first research...Chitin was first discovered by its name from the Greek word“chiton”,which means“mail coat”.It is indeed a polysaccharide made up of naturally occurring acetyl-D-glucosamine monomers.Hatchett was the first researcher who extracted chitin from the shells of mollusks(crabs and lobsters),prawns,and crayfish in 1799.Later in 1811,Henri Braconnot discovered chitin in the cell walls of mushrooms and called it“fungine”.Chitin and chitosan are abundant in the biosphere as essential components of many organisms’exoskeletons and as by-products of the global seafood industry.The biopolymer must be deacetylated before chitosan can be produced.It can also be extracted using microbes in a biological extraction procedure.The development of products that take advantage of the bioactivities of the existing primary commercial source of chitin(crustacean)has lagged expectations.Also,the disadvantages of the present commercial source such as seasonality and competition for other uses among others has been one of the driving forces towards seeking alternative sources of chitin and chitosan in nature.This review highlights some of the efforts made by environmental scholars to locate possible commercial sources of chitin and chitosan in nature over time.展开更多
We studied the depth distribution of periphyton,growing on inundated dead trees in Kenyir Lake,Malaysia in June 1995.The algal floral composition and structure manifested changes down the depth gradient in terms of sp...We studied the depth distribution of periphyton,growing on inundated dead trees in Kenyir Lake,Malaysia in June 1995.The algal floral composition and structure manifested changes down the depth gradient in terms of species richness,abundance,diversity and cell density.In regression analysis,all these algal attributes were negatively correlated with the depth gradients at P<0.05.In terms of species richness,the bacillariophytes showed dominance over the cyanophytes and chlorophytes;whereas with respect to standing crop,the cyanophytes showed dominance over the bacillariophytes and chlorophytes.The chlorophyll a was higher at the mid and bottom-depths than the surface-depth in both the downstream and upstream sites,which showed that vertical productivity or biomass accumulation was greater in low light irradiance.The product-moment correlation analysis showed that conductivity,turbidity,dissolved oxygen,reactive phosphate and ammonium-nitrogen were highly correlated with the algal assemblage data.However,photosynthetic active radiation(PAR) showed poor correlation with the community data.These observations have cast some light on the autoecological characteristics,habitat preferences and environmental responses of tropical periphytic communities.展开更多
Zonal distribution and population biology of llyoplaxfrater were studied in a mangrove mudflat area of Pakistan. The crabs were collected from Korangi creek through transect and quadrat method from low tide level to h...Zonal distribution and population biology of llyoplaxfrater were studied in a mangrove mudflat area of Pakistan. The crabs were collected from Korangi creek through transect and quadrat method from low tide level to high tide level. Two transects were delimited in a mangrove area of Korangi creek （24°79′N/67°20′E）. On each transect, three 0.25 m quadrats were sampled at three tidal levels on a monthly basis during low tide periods from March 2001 to February 2002. A total of 1124 crabs were obtained, of which 482 were males and 642 were females. Density of crabs varied between 0 and 90/m^2. The density and size distribution varied and showed significant differences from low to high tide level, and were positively correlated with the percent moisture, percent organic matter and sediment grain size. The carapace width （CW） ranged from 2.5 to 11.5 mm for male and 2.5 to 11.0 mm for female and was not significantly different. The overall sex ratio did not differ significantly from the expected 1：1 throughout the year in small crabs but was significantly different in adult crabs （Z2 = 49.73） with more male crabs, Size frequency distribution showed recruitment of juvenile crabs （〈 4 mm） nearly throughout the year except during June and July. Presence of ovigerous females in all months with seasonal peaks in September, October, December and May indicates seasonal continuous breeding. Weight of egg mass increases with weight of ovigerous females and show positive linear relationship. The estimated mean diameter of egg was 2.83±0.25μm, and the average number of eggs was 3065±902.展开更多
A fossil-bearing locality near Padhri village,Dhok Pathan,55 km away from the tehsil Dina,Jhelum District,in the Potwar Plateau,Middle Siwaliks,Punjab,northern Pakistan,is significantly rich in mammalian fossils.This ...A fossil-bearing locality near Padhri village,Dhok Pathan,55 km away from the tehsil Dina,Jhelum District,in the Potwar Plateau,Middle Siwaliks,Punjab,northern Pakistan,is significantly rich in mammalian fossils.This site has provided an abundant mammalian fossil fauna of Late Miocene age from the Dhok Pathan Formation(Fm.).The recovered material belongs to four families:Equidae(horses),Rhinocerotidae(rhinos),Bovidae(cows),and Suidae(pigs).We discovered a new skull of hipparionine Hipparion theobaldi from this locality along with 22 specimens from the associated assemblage of fossil mammals.The recovered material includes seven other species:the aceratheriine Chilotherium intermedium,boselaphines Tragoportax punjabicus,Selenoportax vexillarius,Pachyportax latidens,the antelope Gazella lydekkeri and suinine Propotamochoerus hysudricus.The specimens are isolated teeth,fragments of maxilla,mandibles and horn cores.The Dhok Pathan Fm.is generally composed of claystone,siltstone and sandstone beds and,based on the mammalian fauna,the Padhri fossil locality is dated as Late Miocene.Thi99 s formation was deposited in a subtropical paleoenvironment and the predominance of fossil bovids indicates extremely moist conditions with small but frequent standing water bodies.展开更多
In the present work, we compared indices of metabolism and feed conversion efficiency of a semi benthic and two pelagic mari-cultured fish species in the Mediterranean Sea. The metabolism of fish species varies accord...In the present work, we compared indices of metabolism and feed conversion efficiency of a semi benthic and two pelagic mari-cultured fish species in the Mediterranean Sea. The metabolism of fish species varies according to habitat and ecophysiological adaptations. For example, with increasing depth, some species may exhibit adaptations to lower temperature and hypoxic conditions with a reduction in mass specific metabolic rate. Meagre （Argyrosomus regius） is a semi-benthic fish found at depths between 30 m and 300 m. Sea bass （Dicentrarhus labrax） and gilthead sea bream （Sparus auratus） are semi-pelagic fish species widely cultivated in the Mediteranean Sea. The aerobic metabolic potential and feed conversion efficiency of meagre were very different from the sea bass and gilthead sea bream. Compared to these two semic-pelagic fish species, meagre exhibited less efficient feed conversion rate, fillet yield. The results provide an estimate of the quantity of fish required to produce 1 kg of fillet weight, an estimation which is required for the operational management of fish processing companies and for estimating the wastes of fish processing factories during filleting.展开更多
Out of the 48 fishes examined, 40 (83.3%) were infected by 759 parasites, which comprise of trematodes, monogeneans, crustaceans and acanthocephalans. Acanthocephalans and strigeid trematodes were the majority, 23 (47...Out of the 48 fishes examined, 40 (83.3%) were infected by 759 parasites, which comprise of trematodes, monogeneans, crustaceans and acanthocephalans. Acanthocephalans and strigeid trematodes were the majority, 23 (47.9%) of all the parasites, while crustaceans, Ergasilus was the minority (20.8%). Fish with length size greater than 160 mm were infected (prevalence 100%). Strigeids showed the highest prevalence (83.3%) and mean intensity (24.7) in fish of total length 160 - 189 mm while those greater than 219 mm had the least prevalence (20%) and mean intensity (2). Acanthocephalan showed the highest prevalence (87.5%) and mean intensity (15.7) in fish of total length 190 - 219 mm and least prevalence (30.4%) and mean intensity (5.6) in those with 130 - 159 mm in total length. Generally male fish had higher prevalence (88.5%) and mean intensity (21.6) than female fish. However, statistically these were not significant (P > 0.05). A total of 9 parasite taxa were recovered;5 from Oreochromis urolepis, 4 from Citharinus congicus, 2 from Clarias gariepinus and Synodontis maculipinna. Three groups of parasites were common in Oreochromis urolepis, these include Dactylogyrus, Acanthocephala, and strigid. Ergersilus lamelifer was common in Citharinus congicus and Clarias gariepinus. Nematodes, Procamalanus laevionchus and Oxyuridae were common in Synodontis maculipinna and Citharinus congicus respectively.展开更多
Fumonisin B<sub>1</sub> (FB<sub>1</sub>) is produced by fungus of the genus Fusarium (Fusarium verticiloides and F. proliferatum), and occurs predominantly in maize. The consumption of feed con...Fumonisin B<sub>1</sub> (FB<sub>1</sub>) is produced by fungus of the genus Fusarium (Fusarium verticiloides and F. proliferatum), and occurs predominantly in maize. The consumption of feed contaminated with FB<sub>1</sub> has been reported to cause deleterious effects in some fish species. This study was designed to determine the effects of dietary FB<sub>1</sub> on growth and lipids profile of Clarias gariepinus. 450 juvenile catfish were stocked into 5 groups of tanks consisting of 3 tanks per group and fed one of five diets amended with FB<sub>1</sub> (0.0 mg;10.0 mg;20.0 mg;40.0 mg and 80.0 mg FB<sub>1</sub>/kg) for 56 days. At time point’s day 7, 14, 28 and 56, five fish were sampled from each tank weighted, length measured and bled for of lipids profile determinations. Results show that there was a significant reduction (P < 0.05), in the mean body length of the fish fed diets amended with various amounts of FB<sub>1</sub> compared with those fed control diet;also, there was a significant reduction (P < 0.05) in the weight gain of fishes fed diets amended with FB<sub>1</sub> compared with the control. The specific growth rate and the feed conversion ratio at 56 days shows fish fed 0.0 mg FB<sub>1</sub>/kg had the highest specific growth rate (0.39 ± 0.14%/day) and the lowest feed conversion ratio (0.59 ± 0.01) whereas, fish fed 80.0 mg FB<sub>1</sub>/kg had the least specific growth rate (0.07% ± 0.01%/day) and the highest feed conversion ratio (1.95 ± 0.11). Dietary FB<sub>1</sub> caused significant increases (P < 0.05) in serum cholesterol, HDL-C;LDL-C;triglycerides and the sphinganine-sphingosine ratio. Dietary FB<sub>1</sub> at an inclusion rate ≥ 20 mg FB<sub>1</sub>/kg of diet produced significant reduction in weight gain and hyperlipidemia marked by hypercholesterolemia, increased blood high-density lipid cholesterol, increased blood low-density lipid cholesterol, elevated blood triglycerides and elevated sphinganine-sphingosine ratio.展开更多
Nigeria waters are rich with a variety of fish species but only very few are cultured and available for consumption.This study was conducted to know the fillet quality,gut content and condition of Parachanna obscura a...Nigeria waters are rich with a variety of fish species but only very few are cultured and available for consumption.This study was conducted to know the fillet quality,gut content and condition of Parachanna obscura and Clarias agboyiensis in Nigeria using Igbokoda river as a reference because it is a the major fishing site in the nation.Studies were conducted on the viscera somatic index based on the organ weight and the body weight of the fish and the food item consumed by Parachanna obscura and Clarias agboyiensis between May to October,2019 to infer on the fillet quality and gut content of P.obscura and C.agboyiensis in the water body respectively.A summary of food items that constituted the diet of Clarias agboyiensis are Baccillariophyta,fish,fat droplets,dinoflagellate,insect and Chlorophyta which constituted the most important food items both occurring in all stomachs containing food.The fishes has more muscle than the viscera organs which indicate that the weight of the fish before dressing out is higher than the weight of the fish after dressing out.This is suggestive of a good quality of food fish.There was a significant correlation between body weight and total length of specimens found in this study.Increases in total length resulted in corresponding increases in body weight.The result for the condition factor showed was below the expected or standard value(K=1)which shows this species was not in favorable environmental condition.It is therefore necessary to allow phytoplanktons grow well in water body to increase availability of food items to Parachanna obscura and Clarias agboyiensis.P.obscura and C.agboyiensis are also good food fishes of a high fillet quality.They are omnivorous feeders therefore having potentials for aquaculture.展开更多
A total of 140 bacterial isolates have been successfully isolated from various organs of diseased American bullfrog （Rana catesbeiana） cultured in Malaysia. The most frequently isolated bacteria was Edwardsiella sp...A total of 140 bacterial isolates have been successfully isolated from various organs of diseased American bullfrog （Rana catesbeiana） cultured in Malaysia. The most frequently isolated bacteria was Edwardsiella spp. （46 isolates） followed by Aeromonas spp. （33 isolates）, Flavobacterium spp. （31 isolates）, and Vibrio spp. （30 isolates）. Majority of the bacterial isolates were found sensitive to furazolidone （85.0%）, chloramphenicol （85.0%）, oxolinic acid （90.0%）, florfenicol （95.0%）, and flumequine （97.5%）. On the other hand, most of the bacterial isolates were resistant to oleandomycin （77.5%） and lincomycin （87.5%）. Nitrofurantoin and flumequine can be inhibited the growth of all of Vibrio spp. whereas all isolates of Edwardsiella spp. were found sensitive to florfenicol and flumequine. Multiple antibiotic resistance （MAR） index were in range of 0.30-0.40, indicating that bacterial isolates from cultured bullfrogs may have received high risk exposure to the tested antibiotics. In addition, 90-100% of the isolates were resistant to copper, cadmium, and chromium. These results provided insight information on tolerance level of bacterial isolates from cultured bullfrogs to 21 antibiotics as well as heavy metals.展开更多
The response of catfish fed differently timed wet-heat-treated sesame seedmeal was evaluated in the diet of Clarias gariepinus using growth performance, nutrient utilisation and apparent digesti-bility coefficient as ...The response of catfish fed differently timed wet-heat-treated sesame seedmeal was evaluated in the diet of Clarias gariepinus using growth performance, nutrient utilisation and apparent digesti-bility coefficient as indices. Three batches of sesame seed, which were cooked for 10, 20 and 30 minutes, dried, milled, and mechanically defatted using locally made screw press. Each of these differently processed seedmeals was included in the diet of African catfish at varying replacement levels, 15, 30 and 45% with soybean meal. There was good growth performance and nutrient uti-lization by Clarias gariepinus fed with differently timed wet-heat-treated sesame seed that was not significantly different (p > 0.05) from fish fed control diet. More so, the apparent digestibility coef-ficient for organic matter, protein, energy, lipid, fibre, carbohydrate in Clarias gariepinus fed with differently timed wet-heat-treated sesame seedmeal based diets in this study were comparable with the results obtained for fish fed control diets.展开更多
Aspects of the trophic attributes of the mudskipper, Periophthalmus barbarus occurring in the mangrove swamps of Imo River Estuary, Nigeria, were investigated during a 12 month period (April, 1992\_March, 1993). ...Aspects of the trophic attributes of the mudskipper, Periophthalmus barbarus occurring in the mangrove swamps of Imo River Estuary, Nigeria, were investigated during a 12 month period (April, 1992\_March, 1993). Feeding intensity increased with size, it was higher in the dry season(November\_April) than in the wet season(May\_October), monthly changes in the indices of feeding intensity were significantly correlated. Major food objects comprised detritus and benthic algae; crustaceans, insects, macrophyte matter and sand grains were minor food objects while fish, molluscs, Chilopoda, nematodes and fungi were unconsciously devoured objects. Diet varied seasonally; algae and sesarmid crabs were generally more in the dry season than during the rains whereas FPOM and fish increased in the wet over dry season. The mudskipper display a high degree of euryphagy and can be considered as a generalist and an omnivore. The lower trophic status of P. barbarus qualifies it as a good aquaculture candidate. Food richness was higher in big sized class(BSC) than small sized class(SSC). Size based and seasonal variations were not apparent in food richness. Diet breadth was higher in the BSC than the SSC, there was dry season increase in diet breadth.展开更多
A study on the food and feeding habit of Chrysichthys nigrodigitatus （Lacepede） was conducted in River Niger within the region of Oshimili local government area of Delta State Nigeria. A total of 90 specimens were c...A study on the food and feeding habit of Chrysichthys nigrodigitatus （Lacepede） was conducted in River Niger within the region of Oshimili local government area of Delta State Nigeria. A total of 90 specimens were collected with the help of fishermen using gill net, cast net and traps. The fish samples were immediately taken to the laboratory for analysis. Morphometric characteristics such as weight, length, condition factor, egg weight, Gonado Somatic Index （GSI） and sex ratio were determined. The stomach content was analyzed using numerical method to determine the food content. The total length of the fish sampled ranged from 14.40-44.60 cm, while the standard length varied from 11.00 cm to 47.00 cm and the fish body weight ranged between 19.00 g to 503.20 g. Sex ratio 1 female to 1 male was observed. The mean condition factor for both male and female obtained was 1.67. Of all the 90 fishes sampled, none had empty gut representing 100%. The major food items were phytoplankton, plant part and Detritus. Out of 41 females sampled, only 17 had eggs and the eggs were matured at stage IV.展开更多
Culture trial of 7,488 juveniles of the giant freshwater prawn, Macrobrachium vollenhovenii (Herklots, 1857) was carried out for 180 d in concrete tanks to determine their adaptability, survival, feed utilization and ...Culture trial of 7,488 juveniles of the giant freshwater prawn, Macrobrachium vollenhovenii (Herklots, 1857) was carried out for 180 d in concrete tanks to determine their adaptability, survival, feed utilization and growth performance under culture condition. Twelve experimental concrete tanks each measuring 10 m × 5 m × 1.0 m were used for the experiment from March to August 2016. The prawns were stocked two weeks after treatment of tanks with agricultural lime at the rate of 2,279 kg/ha and poultry manure at the rate of 114 kg/ha. Four experimental diets tested were designated as T1: powdered broiler starter, T2: commercial brine shrimp, T3: combination of broiler starter and brine shrimp and T4: Mississippi Agricultural and Forestry Experimental Station (MAFES) diet formula. Diets were randomly assigned to the four treatment tanks and replicated three times in a 4 × 3 = 12 experimental units as a completely randomized design experiment (CRD). Each tank was stocked with 624 juvenile prawns with mean total length of 1.5 cm and body weight of 10.0 g. Prawns were fed at 5% body weight and twice at 0600 h and 1800 h. Sampling for growth was carried out bi-weekly while water quality was tested weekly. Results were statistically evaluated with one way analysis of variance (ANOVA). Water quality of the four tanks was not significantly different (p > 0.05) from one another throughout the culture period and conformed to recommended tolerable limits in prawn culture ponds. Growth performance was best in diet T4 (the MAFES formula), with a survival rate of 75%, mean weight gain (MWG) of 65 g, relative growth rate (RGR) of 650%, specific growth rate (SGR) of 1.12%, average daily growth (ADG) of 0.3 g/day and food conversion ratio (FCR) of 1.44. The above values differed quite significantly (p < 0.05) from growth responses of other diets. The computed gross ratio (GR) of 0.62 suggests that prawn culture is a highly lucrative business.展开更多
A total of 190 bacterial isolates have been successfully isolated from 50 diseased African Catfish （C/arias gariepinus） namely; 70 isolates of Flavobacterium sp., 50 isolates of Aeromonas hydrophila, 30 isolates of ...A total of 190 bacterial isolates have been successfully isolated from 50 diseased African Catfish （C/arias gariepinus） namely; 70 isolates of Flavobacterium sp., 50 isolates of Aeromonas hydrophila, 30 isolates of Edwardsiella tarda and 20 isolate of each Hafnia alvei and Pseudomonas aeruginosa. This study was conducted to investigate bacteria that infected the broodstocks of African catfish cultured at Manir River, Terengganu as well as their antibiogram and Multiple Antibiotic Resistance （MAR） index. In the present study, antibiotic sensitivity and intermediary case were reported as 52.7% and 7.8%, respectively. Meanwhile, antibiotic case was recorded as 34.5%. The MAR index values obtained by each bacterial species was ranging from 0.24 to 0.52 whereas the average MAR index value was 0.39 which indicated that the cultured fish has been highly exposed to tested antibiotics.展开更多
This study was conducted to screen the commercial herbicides for algae control in the aquarium. Three herbicides of ametryn, atrazine and metribuzine were tested at concentrations ranging from 0.625 to 10.00 ppm. It i...This study was conducted to screen the commercial herbicides for algae control in the aquarium. Three herbicides of ametryn, atrazine and metribuzine were tested at concentrations ranging from 0.625 to 10.00 ppm. It is found that ametryn was the most effective herbicide that inhibited algal growth. Ametryn concentration that caused 50% inhibition on algae growth after exposure for 21 days was 0.335 ppm. Survival rate of oruamental fish, Harlequin rasbora （Trigonostigma heteromorpha） and growth rate of aquatic plant （Elodea canadensis） exposed to 10 ppm ametryn were compared with those exposed to algaecide. The result showed that there was no significant difference in survival rate of Harlequin rasbora when exposed to ametryn, algaecide and dechlorinized tap water （control）. However, growth rate of E. canadensis was lower after exposure of ametryn compared to those exposed to algaecide and tap water. These results suggest that ametryn has potential to be used as an algal inhibitor in aquarium.展开更多
The experiment compared the physical characteristics of aqua feed with crude or gelatinized tapioca starch as sources of energy.The bulk density(BD),water absorption index(WAI),water solubility index(WSI),pellet durab...The experiment compared the physical characteristics of aqua feed with crude or gelatinized tapioca starch as sources of energy.The bulk density(BD),water absorption index(WAI),water solubility index(WSI),pellet durability index(PDI)and water stability(WS)were measured in both experimental diets.The results showed significant variations(p<0.05)in BD and WAI in diet with crude tapioca starch while non-significant variations(p>0.05)were recorded for WSI and WS in both diets.The higher BD of a diet,the better its ability in resisting external forces that can cause disintegration.A high BD also reduces ability to the feed material shrinking,thereby preventing loss to feed dust and fines.The results of WSI,WS and PDI of diets denotes that both pellets were water stable and could spend about same time in water but diet with gelatinized starch had a better water absorption index and pellet durability index.Furthermore,proximate composition of diets showed that diets with gelatinized starch had low moisture(9.04%),low fibre(5.24%),and higher ash(13.61%)and lipid(9.64%)contents.It can be concluded from this experiment that diets with gelatinized starch stands the chance of being a better functional feed for small-scale fish farmers in Sub-Saharan Africa.展开更多
This study was carried out to evaluate the effects of dietary replacement of maize with sweet potato peel in the diet of Clarias gariepinus juveniles.The levels of the SPP inclusion in the experimental diets were 0%,2...This study was carried out to evaluate the effects of dietary replacement of maize with sweet potato peel in the diet of Clarias gariepinus juveniles.The levels of the SPP inclusion in the experimental diets were 0%,25%,50%,75%and 100%.All the diets were iso-nitrogenous.One hundred and fifty(150)C.gariepinus juveniles(33 g~35 g)were randomly distributed to five treatments with three replicates each and 5%of their body weight for 12 weeks.Fish carcass proximate compositions analyzed before and after feeding with the experimental diets shows that CP and EE differed significantly(p<0.05)among the experimental fish and the control,except the percentage CP of the fish fed SPP0%and SPP50%in which there was no significant difference(p>0.05).Highest MWG of 207.70±25.95 g was obtained in the fish fed SPP100%followed by 191.30±16.15 g obtained in the fish fed SPP75%.The least MWG of 149.83±16.01 g was recorded in fish fed SPP25%.The highest FCR of 3.61±0.45 g was recorded in the fish fed SPP100%.A steady decrease in FCR was observed with decreasing inclusion levels of SPP meal.However,higher FW,FL,SGR and PER were observed in the experimental fish as from 50%inclusion levels of the SPP.The cost of feed per kg was reduced and the NP and WG increased with increasing levels of SPP and the profitability was enhanced at 100%SPP inclusion level.The results revealed that C.gariepinus juvenile could tolerate up to 50%,75%and 100%inclusion levels of SPP.The best growth performance was recorded in the fish fed SPP100%,therefore,sweet potato peel can replace maize in the diet of C.gariepinus without any inauspicious effect on the growth performance and nutrient utilization.展开更多
基金supported by Ministry of Higher Education,Malaysia through the Translational Research Program entitled Program Traslasional Sektor Makanan Laut Malaysia untuk Kelestarian Pengeluaran Udang Marin dan Penjanaan Pendapatan-Tinggi:Aplikasi Teknologi“Rapid Biofloc”(UMT/PPIJIM/2-2/68/Trans-KPT)grant number[Vot.No:58932].
文摘Global seafood demand has continued to rise amidst challenges to traditional aquaculture operations.Current shrimp aquaculture practice requires high water exchange and discharges toxic effluent to the environment.Biofloc technology(BFT)is self-sustaining and emphasizes nutrient cycling through microbial activity to maintain water quality.The effect of BFT on water quality and profitability of shrimp(Litopenaeus vannamei)culture was determined over a 70-day period.Ponds P1,P2,and P3 were treated with BFT and compared to a control group(P4)without BFT.Bacillus infantis cultured inoculum initiated biofloc development while molasses-maintained C:N ratio of 15:1.One-way ANOVA determined the mean differences in Temperature,pH,dissolved oxygen(DO),total dissolved solid,alkalinity,salinity,ammonia(NH_(3)),nitrates,nitrites(NO_(2)^(-)),calcium,magnesium,as well as shrimp body weight(BW)and total length(TL)across treatments.Profitability was determined by comparing the cost of production with sales and plotting it on a bar chart.BFT shrimp exhibited significantly higher BW(13.6 g)compared to 8.1 g in the control,and maintained a higher survival rate(80–90%)by day 70.Water quality was better managed in BFT,with NH_(3) consistently kept below 0.5mg/L;transient peaks of NO_(2)^(-),more stable pH(averaging at 7.5),and better DO management,maintained above 5 mg/L.BFT provided higher profitability of Ringgit Malaysia(RM)11,019.67(P1)and RM 8651.83(P2)compared to financiallosses in the non-biofloc system.Although operational challenges were reported,BFT showed superior resilience,suggesting that proper technical training and farm management are crucial for its optimization.
文摘This work’s goal was to compile a list of fishing-related violations in order to suggest ways to enhance the surveillance system.In order to accomplish this goal,the following approach was used:Executive consultation and archive exploitation;surveillance agent survey;surveillance system identification and description;identification of offenses and fleet involved in the Guinean exclusive and economic area in recent years;identification and categorization of offense causes;surveillance system evaluation;and suggestion for enhanced surveillance system measures.Monitoring of this strategy showed that:fishing operating zones,administrative paperwork,and fishing gear are all linked to the infractions committed in the Guinean exclusive and economic zone.Records show that there were 308 boardings between 2006 and 2021.IP(Intellectual Property)infringement rates are 59%,Motorized Artisanal Fishing is 25%,and Semi-industrial fishing is 16%.In Motorized Artisanal Fishing,the Guineans have committed 33,the Senegalese have committed 23,and the Leonese have committed 18.In Semi-industrial fishing,the Chinese have committed 17 and the Senegalese have committed 16.According to the stakeholder survey,Vessal Monitoring System monitored 79 vessels in industrial fishing and 49 in Semi-industrial fishing in 2021.Registration certificates,personnel,rescue gear,gross tonnage,coastal state fishing authority,and maritime radio license are typically the primary documents examined at sea.From 2006 to 2022,a total of 135 fleets-80 demersal trawlers,7 cephalopod boats,21 shrimp boats,22 pelagic trawlers,and 5 cargo ships-were implicated in violations in the Guinean exclusive and economic area.By integrating the automatic identification system and Vessal Monitoring systems for fisheries surveillance,establishing a marking system for fishing gear,investing in highly effective launches,and protecting the privacy of patrol activities,Guinea’s surveillance system might be improved more effectively.
文摘Humans have always engaged with their surroundings and the ecology in which they live.However,during the industrial age,this contact has been more intense and has had a substantial impact on environment and ecosystems.For example,overexploitation of natural resources,mining,pollution,and deforestation are all elements that negatively affect biodiversity and natural resources.Few studies have been conducted to evaluate the damage caused,despite the significant uncontrolled pressure from human activity.However,maintaining its environment is essential to the survival of coastal fishing.Goal:This study’s goal was to evaluate how human activity affected Tabounsou’s coastal ecology in order to suggest remedial actions for sustainable management.The following was the methodological approach used:executive consultation and archival analysis;stakeholder survey(locals,farmers,salt producers,fishers,and loggers);inventory of species;anthropogenic activity inventory;evaluation of how human activity affects aquatic life in the research region;suggestion and action for sustainable management;Outcome:Executive consultation indicated that the main issues are:construction projects that reduce the estuary’s surface area;agricultural practices such as woodcutting and salt farming;the rise in resource exploitation;noncompliance with fisheries laws;and the catching of young fish.Eighty-three percent of fisherman ditch their nets on the coast after using them,but only seventeen percent burn them.With a 75%frequency rate,the same survey indicates that most fisherman fish around the coast.In the Tabounsou area,according to loggers’survey,68%of the wood cut is Rhizophora,24%is Avicennia,and 8%is Laguncularia.Three fish stocks,representing nine families and nine species,were identified by the species inventory.At 18%and 15%,respectively,the actors most frequently capture the species Pseudotolithus elongatus and Arius parkii.According to a poll of 30 farmers,90%of them apply fertilizer to their soil,while only 10%do not.During the dry season,salt is grown.According to two actors,Bougna Toro Toro produces 100 kg of salt per day,followed by Khoumawadé,which produces 80 kg,and Toumbibougni,which produces 70 kg.
基金This study is funded by the Long Term Research Grant Scheme(LRGS/1/2018/USM/01/1/1)(LRGS/2018/USM-UKM/EWS/01)granted by Ministry of Higher Education Malaysia for funding this research project.
文摘Chitin was first discovered by its name from the Greek word“chiton”,which means“mail coat”.It is indeed a polysaccharide made up of naturally occurring acetyl-D-glucosamine monomers.Hatchett was the first researcher who extracted chitin from the shells of mollusks(crabs and lobsters),prawns,and crayfish in 1799.Later in 1811,Henri Braconnot discovered chitin in the cell walls of mushrooms and called it“fungine”.Chitin and chitosan are abundant in the biosphere as essential components of many organisms’exoskeletons and as by-products of the global seafood industry.The biopolymer must be deacetylated before chitosan can be produced.It can also be extracted using microbes in a biological extraction procedure.The development of products that take advantage of the bioactivities of the existing primary commercial source of chitin(crustacean)has lagged expectations.Also,the disadvantages of the present commercial source such as seasonality and competition for other uses among others has been one of the driving forces towards seeking alternative sources of chitin and chitosan in nature.This review highlights some of the efforts made by environmental scholars to locate possible commercial sources of chitin and chitosan in nature over time.
基金Supported by the Goverment of Malaysia,Intensified Research in Priority Areas(IRPA Project)(No.50258-J3)
文摘We studied the depth distribution of periphyton,growing on inundated dead trees in Kenyir Lake,Malaysia in June 1995.The algal floral composition and structure manifested changes down the depth gradient in terms of species richness,abundance,diversity and cell density.In regression analysis,all these algal attributes were negatively correlated with the depth gradients at P<0.05.In terms of species richness,the bacillariophytes showed dominance over the cyanophytes and chlorophytes;whereas with respect to standing crop,the cyanophytes showed dominance over the bacillariophytes and chlorophytes.The chlorophyll a was higher at the mid and bottom-depths than the surface-depth in both the downstream and upstream sites,which showed that vertical productivity or biomass accumulation was greater in low light irradiance.The product-moment correlation analysis showed that conductivity,turbidity,dissolved oxygen,reactive phosphate and ammonium-nitrogen were highly correlated with the algal assemblage data.However,photosynthetic active radiation(PAR) showed poor correlation with the community data.These observations have cast some light on the autoecological characteristics,habitat preferences and environmental responses of tropical periphytic communities.
基金funded by the Pakistan Science Foundation project PSF/Res/S-KU/Envr(51) grant to NAQ
文摘Zonal distribution and population biology of llyoplaxfrater were studied in a mangrove mudflat area of Pakistan. The crabs were collected from Korangi creek through transect and quadrat method from low tide level to high tide level. Two transects were delimited in a mangrove area of Korangi creek （24°79′N/67°20′E）. On each transect, three 0.25 m quadrats were sampled at three tidal levels on a monthly basis during low tide periods from March 2001 to February 2002. A total of 1124 crabs were obtained, of which 482 were males and 642 were females. Density of crabs varied between 0 and 90/m^2. The density and size distribution varied and showed significant differences from low to high tide level, and were positively correlated with the percent moisture, percent organic matter and sediment grain size. The carapace width （CW） ranged from 2.5 to 11.5 mm for male and 2.5 to 11.0 mm for female and was not significantly different. The overall sex ratio did not differ significantly from the expected 1：1 throughout the year in small crabs but was significantly different in adult crabs （Z2 = 49.73） with more male crabs, Size frequency distribution showed recruitment of juvenile crabs （〈 4 mm） nearly throughout the year except during June and July. Presence of ovigerous females in all months with seasonal peaks in September, October, December and May indicates seasonal continuous breeding. Weight of egg mass increases with weight of ovigerous females and show positive linear relationship. The estimated mean diameter of egg was 2.83±0.25μm, and the average number of eggs was 3065±902.
文摘A fossil-bearing locality near Padhri village,Dhok Pathan,55 km away from the tehsil Dina,Jhelum District,in the Potwar Plateau,Middle Siwaliks,Punjab,northern Pakistan,is significantly rich in mammalian fossils.This site has provided an abundant mammalian fossil fauna of Late Miocene age from the Dhok Pathan Formation(Fm.).The recovered material belongs to four families:Equidae(horses),Rhinocerotidae(rhinos),Bovidae(cows),and Suidae(pigs).We discovered a new skull of hipparionine Hipparion theobaldi from this locality along with 22 specimens from the associated assemblage of fossil mammals.The recovered material includes seven other species:the aceratheriine Chilotherium intermedium,boselaphines Tragoportax punjabicus,Selenoportax vexillarius,Pachyportax latidens,the antelope Gazella lydekkeri and suinine Propotamochoerus hysudricus.The specimens are isolated teeth,fragments of maxilla,mandibles and horn cores.The Dhok Pathan Fm.is generally composed of claystone,siltstone and sandstone beds and,based on the mammalian fauna,the Padhri fossil locality is dated as Late Miocene.Thi99 s formation was deposited in a subtropical paleoenvironment and the predominance of fossil bovids indicates extremely moist conditions with small but frequent standing water bodies.
文摘In the present work, we compared indices of metabolism and feed conversion efficiency of a semi benthic and two pelagic mari-cultured fish species in the Mediterranean Sea. The metabolism of fish species varies according to habitat and ecophysiological adaptations. For example, with increasing depth, some species may exhibit adaptations to lower temperature and hypoxic conditions with a reduction in mass specific metabolic rate. Meagre （Argyrosomus regius） is a semi-benthic fish found at depths between 30 m and 300 m. Sea bass （Dicentrarhus labrax） and gilthead sea bream （Sparus auratus） are semi-pelagic fish species widely cultivated in the Mediteranean Sea. The aerobic metabolic potential and feed conversion efficiency of meagre were very different from the sea bass and gilthead sea bream. Compared to these two semic-pelagic fish species, meagre exhibited less efficient feed conversion rate, fillet yield. The results provide an estimate of the quantity of fish required to produce 1 kg of fillet weight, an estimation which is required for the operational management of fish processing companies and for estimating the wastes of fish processing factories during filleting.
文摘Out of the 48 fishes examined, 40 (83.3%) were infected by 759 parasites, which comprise of trematodes, monogeneans, crustaceans and acanthocephalans. Acanthocephalans and strigeid trematodes were the majority, 23 (47.9%) of all the parasites, while crustaceans, Ergasilus was the minority (20.8%). Fish with length size greater than 160 mm were infected (prevalence 100%). Strigeids showed the highest prevalence (83.3%) and mean intensity (24.7) in fish of total length 160 - 189 mm while those greater than 219 mm had the least prevalence (20%) and mean intensity (2). Acanthocephalan showed the highest prevalence (87.5%) and mean intensity (15.7) in fish of total length 190 - 219 mm and least prevalence (30.4%) and mean intensity (5.6) in those with 130 - 159 mm in total length. Generally male fish had higher prevalence (88.5%) and mean intensity (21.6) than female fish. However, statistically these were not significant (P > 0.05). A total of 9 parasite taxa were recovered;5 from Oreochromis urolepis, 4 from Citharinus congicus, 2 from Clarias gariepinus and Synodontis maculipinna. Three groups of parasites were common in Oreochromis urolepis, these include Dactylogyrus, Acanthocephala, and strigid. Ergersilus lamelifer was common in Citharinus congicus and Clarias gariepinus. Nematodes, Procamalanus laevionchus and Oxyuridae were common in Synodontis maculipinna and Citharinus congicus respectively.
文摘Fumonisin B<sub>1</sub> (FB<sub>1</sub>) is produced by fungus of the genus Fusarium (Fusarium verticiloides and F. proliferatum), and occurs predominantly in maize. The consumption of feed contaminated with FB<sub>1</sub> has been reported to cause deleterious effects in some fish species. This study was designed to determine the effects of dietary FB<sub>1</sub> on growth and lipids profile of Clarias gariepinus. 450 juvenile catfish were stocked into 5 groups of tanks consisting of 3 tanks per group and fed one of five diets amended with FB<sub>1</sub> (0.0 mg;10.0 mg;20.0 mg;40.0 mg and 80.0 mg FB<sub>1</sub>/kg) for 56 days. At time point’s day 7, 14, 28 and 56, five fish were sampled from each tank weighted, length measured and bled for of lipids profile determinations. Results show that there was a significant reduction (P < 0.05), in the mean body length of the fish fed diets amended with various amounts of FB<sub>1</sub> compared with those fed control diet;also, there was a significant reduction (P < 0.05) in the weight gain of fishes fed diets amended with FB<sub>1</sub> compared with the control. The specific growth rate and the feed conversion ratio at 56 days shows fish fed 0.0 mg FB<sub>1</sub>/kg had the highest specific growth rate (0.39 ± 0.14%/day) and the lowest feed conversion ratio (0.59 ± 0.01) whereas, fish fed 80.0 mg FB<sub>1</sub>/kg had the least specific growth rate (0.07% ± 0.01%/day) and the highest feed conversion ratio (1.95 ± 0.11). Dietary FB<sub>1</sub> caused significant increases (P < 0.05) in serum cholesterol, HDL-C;LDL-C;triglycerides and the sphinganine-sphingosine ratio. Dietary FB<sub>1</sub> at an inclusion rate ≥ 20 mg FB<sub>1</sub>/kg of diet produced significant reduction in weight gain and hyperlipidemia marked by hypercholesterolemia, increased blood high-density lipid cholesterol, increased blood low-density lipid cholesterol, elevated blood triglycerides and elevated sphinganine-sphingosine ratio.
文摘Nigeria waters are rich with a variety of fish species but only very few are cultured and available for consumption.This study was conducted to know the fillet quality,gut content and condition of Parachanna obscura and Clarias agboyiensis in Nigeria using Igbokoda river as a reference because it is a the major fishing site in the nation.Studies were conducted on the viscera somatic index based on the organ weight and the body weight of the fish and the food item consumed by Parachanna obscura and Clarias agboyiensis between May to October,2019 to infer on the fillet quality and gut content of P.obscura and C.agboyiensis in the water body respectively.A summary of food items that constituted the diet of Clarias agboyiensis are Baccillariophyta,fish,fat droplets,dinoflagellate,insect and Chlorophyta which constituted the most important food items both occurring in all stomachs containing food.The fishes has more muscle than the viscera organs which indicate that the weight of the fish before dressing out is higher than the weight of the fish after dressing out.This is suggestive of a good quality of food fish.There was a significant correlation between body weight and total length of specimens found in this study.Increases in total length resulted in corresponding increases in body weight.The result for the condition factor showed was below the expected or standard value(K=1)which shows this species was not in favorable environmental condition.It is therefore necessary to allow phytoplanktons grow well in water body to increase availability of food items to Parachanna obscura and Clarias agboyiensis.P.obscura and C.agboyiensis are also good food fishes of a high fillet quality.They are omnivorous feeders therefore having potentials for aquaculture.
基金funded by Universiti Malaysia Terengganu, Malaysia
文摘A total of 140 bacterial isolates have been successfully isolated from various organs of diseased American bullfrog （Rana catesbeiana） cultured in Malaysia. The most frequently isolated bacteria was Edwardsiella spp. （46 isolates） followed by Aeromonas spp. （33 isolates）, Flavobacterium spp. （31 isolates）, and Vibrio spp. （30 isolates）. Majority of the bacterial isolates were found sensitive to furazolidone （85.0%）, chloramphenicol （85.0%）, oxolinic acid （90.0%）, florfenicol （95.0%）, and flumequine （97.5%）. On the other hand, most of the bacterial isolates were resistant to oleandomycin （77.5%） and lincomycin （87.5%）. Nitrofurantoin and flumequine can be inhibited the growth of all of Vibrio spp. whereas all isolates of Edwardsiella spp. were found sensitive to florfenicol and flumequine. Multiple antibiotic resistance （MAR） index were in range of 0.30-0.40, indicating that bacterial isolates from cultured bullfrogs may have received high risk exposure to the tested antibiotics. In addition, 90-100% of the isolates were resistant to copper, cadmium, and chromium. These results provided insight information on tolerance level of bacterial isolates from cultured bullfrogs to 21 antibiotics as well as heavy metals.
文摘The response of catfish fed differently timed wet-heat-treated sesame seedmeal was evaluated in the diet of Clarias gariepinus using growth performance, nutrient utilisation and apparent digesti-bility coefficient as indices. Three batches of sesame seed, which were cooked for 10, 20 and 30 minutes, dried, milled, and mechanically defatted using locally made screw press. Each of these differently processed seedmeals was included in the diet of African catfish at varying replacement levels, 15, 30 and 45% with soybean meal. There was good growth performance and nutrient uti-lization by Clarias gariepinus fed with differently timed wet-heat-treated sesame seed that was not significantly different (p > 0.05) from fish fed control diet. More so, the apparent digestibility coef-ficient for organic matter, protein, energy, lipid, fibre, carbohydrate in Clarias gariepinus fed with differently timed wet-heat-treated sesame seedmeal based diets in this study were comparable with the results obtained for fish fed control diets.
文摘Aspects of the trophic attributes of the mudskipper, Periophthalmus barbarus occurring in the mangrove swamps of Imo River Estuary, Nigeria, were investigated during a 12 month period (April, 1992\_March, 1993). Feeding intensity increased with size, it was higher in the dry season(November\_April) than in the wet season(May\_October), monthly changes in the indices of feeding intensity were significantly correlated. Major food objects comprised detritus and benthic algae; crustaceans, insects, macrophyte matter and sand grains were minor food objects while fish, molluscs, Chilopoda, nematodes and fungi were unconsciously devoured objects. Diet varied seasonally; algae and sesarmid crabs were generally more in the dry season than during the rains whereas FPOM and fish increased in the wet over dry season. The mudskipper display a high degree of euryphagy and can be considered as a generalist and an omnivore. The lower trophic status of P. barbarus qualifies it as a good aquaculture candidate. Food richness was higher in big sized class(BSC) than small sized class(SSC). Size based and seasonal variations were not apparent in food richness. Diet breadth was higher in the BSC than the SSC, there was dry season increase in diet breadth.
文摘A study on the food and feeding habit of Chrysichthys nigrodigitatus （Lacepede） was conducted in River Niger within the region of Oshimili local government area of Delta State Nigeria. A total of 90 specimens were collected with the help of fishermen using gill net, cast net and traps. The fish samples were immediately taken to the laboratory for analysis. Morphometric characteristics such as weight, length, condition factor, egg weight, Gonado Somatic Index （GSI） and sex ratio were determined. The stomach content was analyzed using numerical method to determine the food content. The total length of the fish sampled ranged from 14.40-44.60 cm, while the standard length varied from 11.00 cm to 47.00 cm and the fish body weight ranged between 19.00 g to 503.20 g. Sex ratio 1 female to 1 male was observed. The mean condition factor for both male and female obtained was 1.67. Of all the 90 fishes sampled, none had empty gut representing 100%. The major food items were phytoplankton, plant part and Detritus. Out of 41 females sampled, only 17 had eggs and the eggs were matured at stage IV.
文摘Culture trial of 7,488 juveniles of the giant freshwater prawn, Macrobrachium vollenhovenii (Herklots, 1857) was carried out for 180 d in concrete tanks to determine their adaptability, survival, feed utilization and growth performance under culture condition. Twelve experimental concrete tanks each measuring 10 m × 5 m × 1.0 m were used for the experiment from March to August 2016. The prawns were stocked two weeks after treatment of tanks with agricultural lime at the rate of 2,279 kg/ha and poultry manure at the rate of 114 kg/ha. Four experimental diets tested were designated as T1: powdered broiler starter, T2: commercial brine shrimp, T3: combination of broiler starter and brine shrimp and T4: Mississippi Agricultural and Forestry Experimental Station (MAFES) diet formula. Diets were randomly assigned to the four treatment tanks and replicated three times in a 4 × 3 = 12 experimental units as a completely randomized design experiment (CRD). Each tank was stocked with 624 juvenile prawns with mean total length of 1.5 cm and body weight of 10.0 g. Prawns were fed at 5% body weight and twice at 0600 h and 1800 h. Sampling for growth was carried out bi-weekly while water quality was tested weekly. Results were statistically evaluated with one way analysis of variance (ANOVA). Water quality of the four tanks was not significantly different (p > 0.05) from one another throughout the culture period and conformed to recommended tolerable limits in prawn culture ponds. Growth performance was best in diet T4 (the MAFES formula), with a survival rate of 75%, mean weight gain (MWG) of 65 g, relative growth rate (RGR) of 650%, specific growth rate (SGR) of 1.12%, average daily growth (ADG) of 0.3 g/day and food conversion ratio (FCR) of 1.44. The above values differed quite significantly (p < 0.05) from growth responses of other diets. The computed gross ratio (GR) of 0.62 suggests that prawn culture is a highly lucrative business.
文摘A total of 190 bacterial isolates have been successfully isolated from 50 diseased African Catfish （C/arias gariepinus） namely; 70 isolates of Flavobacterium sp., 50 isolates of Aeromonas hydrophila, 30 isolates of Edwardsiella tarda and 20 isolate of each Hafnia alvei and Pseudomonas aeruginosa. This study was conducted to investigate bacteria that infected the broodstocks of African catfish cultured at Manir River, Terengganu as well as their antibiogram and Multiple Antibiotic Resistance （MAR） index. In the present study, antibiotic sensitivity and intermediary case were reported as 52.7% and 7.8%, respectively. Meanwhile, antibiotic case was recorded as 34.5%. The MAR index values obtained by each bacterial species was ranging from 0.24 to 0.52 whereas the average MAR index value was 0.39 which indicated that the cultured fish has been highly exposed to tested antibiotics.
文摘This study was conducted to screen the commercial herbicides for algae control in the aquarium. Three herbicides of ametryn, atrazine and metribuzine were tested at concentrations ranging from 0.625 to 10.00 ppm. It is found that ametryn was the most effective herbicide that inhibited algal growth. Ametryn concentration that caused 50% inhibition on algae growth after exposure for 21 days was 0.335 ppm. Survival rate of oruamental fish, Harlequin rasbora （Trigonostigma heteromorpha） and growth rate of aquatic plant （Elodea canadensis） exposed to 10 ppm ametryn were compared with those exposed to algaecide. The result showed that there was no significant difference in survival rate of Harlequin rasbora when exposed to ametryn, algaecide and dechlorinized tap water （control）. However, growth rate of E. canadensis was lower after exposure of ametryn compared to those exposed to algaecide and tap water. These results suggest that ametryn has potential to be used as an algal inhibitor in aquarium.
文摘The experiment compared the physical characteristics of aqua feed with crude or gelatinized tapioca starch as sources of energy.The bulk density(BD),water absorption index(WAI),water solubility index(WSI),pellet durability index(PDI)and water stability(WS)were measured in both experimental diets.The results showed significant variations(p<0.05)in BD and WAI in diet with crude tapioca starch while non-significant variations(p>0.05)were recorded for WSI and WS in both diets.The higher BD of a diet,the better its ability in resisting external forces that can cause disintegration.A high BD also reduces ability to the feed material shrinking,thereby preventing loss to feed dust and fines.The results of WSI,WS and PDI of diets denotes that both pellets were water stable and could spend about same time in water but diet with gelatinized starch had a better water absorption index and pellet durability index.Furthermore,proximate composition of diets showed that diets with gelatinized starch had low moisture(9.04%),low fibre(5.24%),and higher ash(13.61%)and lipid(9.64%)contents.It can be concluded from this experiment that diets with gelatinized starch stands the chance of being a better functional feed for small-scale fish farmers in Sub-Saharan Africa.
文摘This study was carried out to evaluate the effects of dietary replacement of maize with sweet potato peel in the diet of Clarias gariepinus juveniles.The levels of the SPP inclusion in the experimental diets were 0%,25%,50%,75%and 100%.All the diets were iso-nitrogenous.One hundred and fifty(150)C.gariepinus juveniles(33 g~35 g)were randomly distributed to five treatments with three replicates each and 5%of their body weight for 12 weeks.Fish carcass proximate compositions analyzed before and after feeding with the experimental diets shows that CP and EE differed significantly(p<0.05)among the experimental fish and the control,except the percentage CP of the fish fed SPP0%and SPP50%in which there was no significant difference(p>0.05).Highest MWG of 207.70±25.95 g was obtained in the fish fed SPP100%followed by 191.30±16.15 g obtained in the fish fed SPP75%.The least MWG of 149.83±16.01 g was recorded in fish fed SPP25%.The highest FCR of 3.61±0.45 g was recorded in the fish fed SPP100%.A steady decrease in FCR was observed with decreasing inclusion levels of SPP meal.However,higher FW,FL,SGR and PER were observed in the experimental fish as from 50%inclusion levels of the SPP.The cost of feed per kg was reduced and the NP and WG increased with increasing levels of SPP and the profitability was enhanced at 100%SPP inclusion level.The results revealed that C.gariepinus juvenile could tolerate up to 50%,75%and 100%inclusion levels of SPP.The best growth performance was recorded in the fish fed SPP100%,therefore,sweet potato peel can replace maize in the diet of C.gariepinus without any inauspicious effect on the growth performance and nutrient utilization.
