Journal of FisheriesSciences.com
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Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.3.165
Ghana’s fisheries sector comprises 485 fish species. The fish industry contributes to the nation’s economy annually representing 4.5 % of the Gross Domestic Product (GDP) and twelve (12) % contributions to agriculture. There are several fish processing methods in Ghana such as smoking, salting, frying, sun-drying, freezing, and fermentation. Smoking is one of the common ways of preserving fish in large quantities. Wet hot smoking and dry hot smoking are the two forms of fish smoking which consist of three stages of smoking fish namely; cooking stage, drying stage and smoking stage. Predominately, the fish smoking industry is mainly dominated by women and young girls. Fish processing activities are done around and along the coastal waters and river banks. The technologies used in fish smoking in Ghana are improved types of conventional fish smoking ovens, chorkor smokers, oil drums and acceptance of upgraded smoking techniques. Usually, the fish species smoked are catfish, herring, mackerel, anchovy, and tuna. The smoked fish are stored in empty baskets line with brown papers and as well covered with brown papers. Women involved engaged in fish smoking face some challenges such as lack of formal education, unavailability of credits, low capital and prone to respiratory diseases. Also, the smoked fish are prone to microbial hazards and insect pest infestation. Moisture, food nutrient, pH and temperature affect growth in microorganisms in food (smoked fish). Fish smoking plays a vital role in poverty alleviation as women, and young girls depend on fisheries directly and indirectly for their livelihoods. Significantly, fish smoking reduce post-harvest losses. Also, few interventions have shown that fish smoking in Ghana has potential in improving the fisheries sector although there is limited summarized information regarding fish smoking in Ghana. The purpose of this review is to compile relevant information about the nature of fish smoking industry in Ghana.
Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.2.163
In order to reduce the surging acceleration of ocean fishing boats and improve the comfort of crews, based on the theory of regular wave and irregular wave potential flow, the six- Degree-of-Freedom (6DOF) motion performance, wave excitation forces and seasickness incidence of crew before and after modification of an ocean fishing boats were predicted and analyzed by panel method. The forecasting results show that the motion range of the modified fishing boats is obviously reduced and the seasickness incidence has been significantly improved.
Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.3.164
The present study reports the bioaccumulation of cadmium (Cd), zinc (Zn), lead (Pb) and mercury (Hg) in the gills, muscles and intestine of Tilapia zillii, Malapterurus electricus and Clarias gariepinus sampled from fishermen at Niger River, Onitsha shelf. Heavy metals in gills, muscles and intestine of fishes was investigated using Varian AA240 Atomic Absorption Spectrophotometer. Mean cadmium concentration in the fish organs was highest (0.068 ± 0.02 mg/kg) in the gills and lowest (0.040 ± 0.01 mg/kg) in the muscles. The descending order of mean cadmium concentration in the organs is gills > intestine > muscles. T. zillii and C. gariepinus had the maximum and minimum mean cadmium concentration of 0.087 ± 0.04 mg/kg and 0.043 ± 0.01 mg/kg, respectively. Cadmium concentration in the fish organs were lower than the FAO/WHO standard for seafood, thus the fishes with this levels of heavy metals are safe for human consumption. The mean concentration of zinc in the organs of the studied fish species was highest (8.180 ± 3.508 mg/kg) in intestine and lowest (4.176 ± 1.091 mg/ kg) in the muscles. The descending order was intestine > gills > muscles. Mean zinc concentration was maximum (8.848 ± 3.39 mg/kg) in T. zillii and minimum (5.084 ± 1.17 mg/kg) in M. electricus. These values were below the FAO/WHO recommended standard limit of zinc (10–20 mg/kg) in fish samples. Lead and mercury were not detected in any of the fish. The result obtained in this study, revealed that Niger River is contaminated to varying levels by zinc and cadmium. Control measures recommended include public enlightenment on the need to desist from anthropogenic activities that could lead to water pollution.
Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.1.157
Blue crabs (Callinectes spp.) are widely distributed around coastal regions being usually exploited by artisanal fishing through specific fishing gears, like as crab traps. Notably, two crab traps types are adopted in Brazil: (I) rectangular crab traps and (II) circular crab traps. Empirically, fishermen suggest that the geometry of these fishing gears amongst the wind regimes in shallow waters are directly related to the catch success, that is, the blue crabs capture into the crab traps. However, these empirical observations have not been proven by academy. Thus, the present study analysed the performance of circular and rectangular traps during twenty campaigns in a coastal lagoon located in Laguna, Santa Catarina–Brazil. The results showed that circular crab traps obtained the highest catches of Callinectes spp. than rectangular crab traps. We observed that wind direction can influence the catch performance in both fishing gears and the best catch performance in our study region were during NE and SO wind quadrants.
Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.1.158
Ethiopia has a rich diversity of ichthyofauna in its lakes, rivers and reservoirs. This study was conducted to identify fish species composition, estimate relative abundance, and assess length–weight relationship and condition factor for the dominant fish species in Gilo River and its nearby wetlands in Akobo district, Gambella Region, Ethiopia. Baro River in Gambella region is documented as the most diverse in fish species. Besides this, its nearby wetlands, tributaries and lakes which are expected to have rich fish species are least explored for their fish diversity. Samples were collected from selected sites using gill nets of various mesh sizes and hooks and lines. Fish sampling was done twice in dry season (December, 2016 and March, 2017) and twice in wet season (May and June, 2017). A total of 911 specimens were collected. These were identified into 27 species, 21 genera, 17 families and five orders. The Shannon diversity index (2.28) of fish species was higher in river than in wetlands (1.85); the same is true for the index of evenness for river (0.69) was also higher than the wetlands (0.67). The length-weight relationship of most of the species evaluated demonstrated positive allometric growth. Seasonal variations in the mean FCF of the most dominant species were statistically insignificant (p>0.05) except for Clarias gariepinus and Citharinus citharus. All the species identified in this study are new report to Gilo River and its nearby wetlands representing a baseline data for the study area. Anthropogenic activities i.e. fishing, farming, construction and other domestic activities were observed in the study sites. Plausible management options have to be encouraged to ensure sustainable utilization of the fisheries resources of the study area.
Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.2.159
The aim of this work is to propose an alternative management and control strategy of crayfishing Procambarus clarkii in the Doñana area. A simulation model was developed (Stella 8.0) to evaluate the effects of different fishing effort on crayfish populations during certain times of the year. Then different management options were simulated: Strategy 0: No fishing activity, Strategy 1: Obtaining the maximum yield of crayfish following the current fishing effort regulations, and Strategy 2: Obtaining the maximum yield of crayfish by restricting the fishing effort to the period of the greatest production. The model explained 73.68% of the variance in population biomass. A review and resetting of the crayfishing regulations in this area according to the periods proposed in Strategy 2, was recommended. This management proposal in the developed model was the one that ensures sustainable yields at the same time that preserves biodiversity by restricting the harvesting of crayfish to rice fields and channels from April to September.
Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.2.161
This work investigated survival and growth performance of male and female Potamon ebonyicum, at different Stocking Densities (SD) with 38% crude protein fish feed, in intensive culture system for six weeks. Experimental treatments were three in number viz., TI, TII and TIII. The TI contained only female, TII contained equal number of male and female, and TIII contained more females than male. The SD ranged from 1 crabT-1 to 3 CrabsT-1. All the male and female crabs survived first half (3 weeks) of the experimental period. Survival period of more than four weeks was recorded in the treatments with more than one female. Growth rates were insignificant and unevenly distributed. Yield was higher in the treatment with equal number of male and female than in the other ones. There was insignificant change in the growth rates as compared to records of previous investigations with the crab species. The narrow gap in the size of small ones, weight differential and their growth rates might assist aqua culturists to adapt SD and forecast yield in the freshwater crab. It could be suggested however that increment in the number of females during high density culture might enhance yield.
Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.2.160
Diatoms are unicellular aquatic microorganisms that belong to a major group of algae called the goldenbrown algae. Diatoms get energy from sunlight and grow use organic matter as food (Carbon source) grown in aquaculture pond. They are the major oxygen producers in the world generates 20% oxygen on the planet earth. Different species of diatoms are cultured/grown in marine water and freshwater which helps for the juveniles as their primary food for shrimp and fish fry. In the larval stages of fish fry/shrimp larvae diatoms are the first food of choice. A unique product Diatomix which enhances the growth of diatoms in the pond by its micro mineral nutrient composition helps full fill the nutritional needs of aquatic species.
Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.1.156
Sand smelt fish (Atherina hepsetus) one of the low economic fish and unacceptable from consumers in Qarun lake, Egypt. Sand smelt fish burger and finger made from sand smelt fish with soybean flour (SF) and minced boiled potatoes (MBP) to improve the economic value for fish. Changes in proximate composition of sand smelt fish products during frozen storage were determined. Chemical analysis indicated that moisture, protein and fat contents of burger and fingers samples gradually decreased during frozen storage period while ash and carbohydrate contents increased during frozen storage. No considerable changes in cooking loss could be observed in the early stages of frozen storage. Meanwhile, as the storage period prolonged, cooking loss values increased. The filling materials SF and MBP used in the production of fish products showed an observed effect in maintaining the chemical composition of the products for 90 days of frozen storage. It can be concluded that sand smelt fish products opening an opportunity for this good nutritious protein source to be used as a daily food.
Journal of FisheriesSciences.com, Volume 13; doi:10.36648/1307-234x.13.3.166
Haematological indices are essential diagnostic tools used to evaluate the health status of fish. Many publications have been stated by different works that qualitative and quantitative variations in haematological parameters; for instance White Blood Cells (WBCs), Red Blood Cells (RBCs), Haematocrit (Hct), Haemoglobin (Hb) content, Mean Corpuscular Haemoglobin Concentration (MCHC), Mean Corpuscular Haemoglobin (MCH) and Mean Corpuscular Volume (MCV) in fish, offer an indication of the health status of the fish. The uses of probiotics as biological control agents in aquaculture have replaced the usage of chemotherapeutics, is an approach in the build-up in aquaculture environments. In the cultured fish, the use of probiotics in monospecies or multispecies forms has been reported to stimulate specific and non-specific immune parameters including lysozyme activities and phagocytic, expression of various cytokines as well as improvement of blood profiles of many fish increasing resistance diseases and to other environmental perturbations such as physiological stressors. Interestingly, many researchers have shown that haematological indices in fish continue to offer a valuable diagnostic tool; and progress is made in establishing a reasonable range of values for blood parameters of different fish species. Also, many interventions have shown that probiotics used in aquaculture have potential in improving blood profiles of fish; although there are not many summarised information regarding the effects of probiotics on haematological parameters in fish. The purpose of this review is to synthesise the influences of probiotics on haematological parameters in fisha.