African Journal of Fisheries Science

African Journal of Fisheries Science ISSN 2375-0715 Vol. 13 (2), pp. 001-010, February, 2025. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Investigating Soybean Meal as a Protein Source for Argyrosomus regius (Asso, 1801) in the Sciaenidae Family

Jorge Velazco-Vargas, Silvia Martínez-Llorens, Miguel Jover Cerda and Ana Tomás-Vidal

Research Group in Aquatic Resources, Institute of Animal Science and Technology,
Polytechnic University of Valencia, Valencia, Spain.

Accepted 12 December, 2024

Abstract

The meagre (Argyrosomus regius) is a carnivorous fish which requires diets with higher protein content, causing an increment in diets cost. A way to diminish this cost is to use vegetable meals like soybean meal (SB). So the aim of this trial was to determine the optimum inclusion level of defatted soybean meal in experimental diets for this species. 800 fishes (165 g) were distributed in 8 tanks, two replicates per treatment. Four isoproteic (50% CP) and isolipidic (17% Cl) diets were formulated with four levels of soybean meal inclusion, 0, 15, 30 and 45%. The trial lasted 107 days. Meagre fed diets 15 and 30% obtained the highest final weight. There were no significant differences among treatments in the feed conversion rate (FCR) and the protein efficiency (PER). According to the quadratic regression, the optimum SB inclusion to maximize thermal growth coefficient (TGC) was 26.4% and for FCR was 27.6%. No significant differences were observed in energy, protein and amino acid retention among diets. The inclusion of SB in meagre diets can generate a decrease in the use of fish meal and in turn reduce the cost of producing meagre Mediterranean aquaculture industry.

Key words: Argyrosomus regius, fish meal replacement, defatted soybean meal, economic analysis.

African Journal of Fisheries Science ISSN 2375-0715 Vol. 13 (1), pp. 001-007, January, 2025. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Review

Exploring the Production and Marketing Frameworks for Tilapia Farming in China

Matlala Moloko P.^1,2, Kpundeh Mathew D.^1,2 and Yuan Yongming^1,2*

¹Wuxi Fishery College, Nanjing Agricultural University, Wuxi, 214081 China. ²key Laboratory of Freshwater Fisheries and Germplasm Resources Utilization, Ministry of Agriculture, Freshwater Fisheries Resource Center of Chinese Academy of Fishery Sciences, Wuxi 214081, Jiangsu China.

Accepted 21 December, 2024

Abstract

Tilapia has become one of the major species of aquatic products in close link with both domestic and international markets. Nowadays, the demand for fish and fisheries product has being exacerbated by the continued increase in human population the world over. This was due to the fact that global captured fishery was declining following the increased human exploitation for the commercially important fishes. Aquaculture or fish farming has become one of the solutions to maintaining the continuous supply of fish to commercial markets. China was by far the largest producer and exporter of tilapia products irrespective of some constraints such as soaring production costs, price and weather fluctuations. In the country, tilapia production was mostly carried out in the southern and southeastern coastal areas where subtropical conditions favored the growth and reproduction of the species. This paper reports on production and marketing systems of tilapia in China. Tilapia products produced in China had to pass through different channels before reaching their final consumers. Major international markets for tilapia products produced in China included among others, the United State, European Union and Russia. This work will guide potential investors and competitors for tilapia market in China and the world at large.

Key words: Tilapia production, marketing system/channels, export, China.
 

African Journal of Fisheries Science ISSN 2375-0715 Vol. 13 (1), pp. 001-007, January, 2025. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

The Role of Eudrilus eugeniae Earthworms in Feeding Heteroclarias Fingerlings

C. O. Monebi* and A. A. A. Ugwumba

Hydrobiology and Fisheries Research Unit, Department of Zoology, University of Ibadan, Ibadan, Oyo State, Nigeria.

Accepted 14 December, 2024

Abstrat

The earthworm, Eudrilus eugeniae was cultured for 12 weeks and its meal utilized as a replacement for fish meal in the diet of fingerlings of the mud catfish hybrid (♂Heterobranchus longifilis X ♀Clarias gariepinus) called Heteroclarias. Two hundred and seventy adult E. eugeniae were cultured in three substrates: Soil, cellulose, or a mixture of cellulose and soil. The worms were harvested at the end of the culture period, processed by oven-drying and grounded into powdery form as earthworm meal. Cellulose substrate was the best for E. eugeniae culture with the highest weight gain and relative growth rate. The earthworm meal produced was used to replace commercial fish meal in five compounded diets at levels of 0 (control), 25, 50, 75 or 100%. The diets were fed to Heteroclarias fingerlings to evaluate the effect of earthworm meal in comparison with fish meal on the growth and nutrient utilization of the fingerlings. The feeding experiment was carried out in 40 L plastic tanks using 5 tanks per treatment and 15 fingerlings per tank, and the fingerlings were fed 5% of their body weight on a daily basis for 10 weeks. Highest mean weight gain was in fish fed 75% earthworm meal, while relative and specific growth rates were highest in fish fed 25% earthworm meal and lowest in fish fed the control diet. Food conversion ratio was lowest in fish fed 50% earthworm meal and highest in fish fed 100% earthworm meal. These results indicate that replacement of fish meal with earthworm meal at 50 to 75% inclusion level is suitable for optimal growth performance and nutrient utilization in Heteroclarias fingerlings.

Key words: Eudrilus eugeniae, culture substrates, Heteroclarias, growth rate.

African Journal of Fisheries Science ISSN 2375-0715 Vol. 12 (7), pp. 001-010, July, 2024. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Occurrence and Dimension Characteristics of Mnemiopsis leidyi (Ctenophora) in the Southwest Caspian Sea

Siamak Bagheri^1,2*, Mashhor Mansor², Azemat Ghandi¹ and Esmaeil Yosefzad¹

¹Inland Waters Aquaculture Institute, Iranian Fisheries Research Organization, 66 Anzali, Iran.
²School of Biological Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia.

Accepted 28 January, 2024

Abstract

Temporal and vertical distributions of Mnemiopsis leidyi were studied along three transects namely Lisar, Anzali and Sephidrood in the southwestern Caspian Sea during 2001 to 2010. The maximum lengths of the ctenophore were 60 to 70 mm, and bulk of individuals (90.6%) were <5 mm in length. The means of abundance and biomass during the whole period were 3032 ind/m2 and 293.54 g/m2, respectively. The highest average abundance value (1017 ind/m2) was measured in summer 2006 and the lowest abundance value (54 ind/m2) was in spring 2010. The average biomass of M. leidyi ranged between 1175.40 and 0.85 g/m2 in summer 2005 and winter 2008, respectively. The highest annual of abundance and biomass were obtained in 2005 and 2006. The dominant of M. leidyi bulk occurred above 20 m depth, whilst the ctenophore population sharply decreased below 20 m. The seasonal pattern of M. leidyi is related to water temperature, as evidenced from the positive correlation between the water temperature and M. leidyi population.

Key words: Mnemiopsis leidyi, abundance, biomass, size, Caspian Sea.
 

African Journal of Fisheries Science ISSN 2375-0715 Vol. 12 (7), pp. 001-007, July, 2024. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Exploring the Dynamics of Gillnet Fishing in the Lower Nun River: A Study of Selectivity, Seasonal, Tidal, and Photoperiod Effects

Martin E. Allison¹* and Daniel Okadi²

¹Department of Fisheries and Livestock Production, Niger Delta University, Wilberforce Island P. M. B. 017 Yenagoa,
Bayelsa State, Nigeria.
²Department of Fisheries and Aquatic Environment, Rivers State University of Science and Technology, Port Harcourt,
Rivers State, Nigeria.

Accepted 21 December, 2023

Abstract

The fish species of the lower Nun River was sampled to determine gillnet selectivity and the effect of season, tide and photoperiod variation on the catch. A total of 11,156 specimens were caught belonging to 14 families consisting of 25 species. Gillnet selectivity was observed with a declining trend from the largest mesh size net of 15 mm (58%) in number and 59% by weight, 12 mm (33%) in number and 33% by weight with the least catch of about 9% by number and 8% by weight from the smallest (8 mm) net. In terms of seasonal variation, the rainy season catches were significantly higher (P< 0.05) than the dry season with relative abundance of 67 and 32% respectively. Tidal variation in the catches showed that catches were higher during the low tidal period (61%) than the high tide (39%). Significant photoperiod differences (P < 0.05) were observed with higher catches by day (58%) than by night.

Key words: Gillnet selectivity, seasonal, tidal, photoperiod, variation, Nun River.

African Journal of Fisheries Science ISSN 2375-0715 Vol. 12 (6), pp. 001-005, June, 2024. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Helminth Parasite Diversity in Two Clarias Species from the Ogun River and Asejire Dam, Southwestern Nigeria

Salawu M. T.¹, Morenikeji O. A.²*, Sowunmi A. A.² and Odaibo A. B.²

¹Department of Biological Sciences, Osun State University, Osun State, Nigeria.
²Department of Zoology, University of Ibadan, Oyo State, Nigeria.

Accepted 10 March, 2024

Abstract

A total of 250 randomly selected fish specimens consisting of 72 Clarias gariepinus and 51 Clarias pachynema from Ogun River around the cattle market, Isheri, Ogun State. 73 C. pachynema and 54 C. gariepinus from Asejire Dam (which has not been reported to be polluted) in south-west Nigeria were sampled for helminth infection between September 2008 and February 2009. All helminthic infections observed and recorded were restricted to the stomach, intestine and gill chamber. The helminths recovered included three cestodes, Wenyonia sp., Polyonchobothrium sp. and Pleurocercoid larva, a nematode, Procamallanus sp. and one digenean, Clinostomum sp. Prevalence and mean intensity of parasitic infection were higher in specimens from the Ogun River than those from the Asejire Dam. Overall, parasite prevalence of 75 and 45.1% were recorded for C. gariepinus and C. pachynema from the Ogun River, respectively, while 25.9 and 31.5% were recorded for C. gariepinus and C. pachynema, respectively, for the Asejire Dam. Male C. gariepinus from the Ogun River had the highest infection rate (76.5%), while those from Asejire Dam had the lowest (21.43%). No significant difference in the prevalence of parasitic infection in relation to the host sizes (P > 0.05) was recorded; however, largest size fishes had no parasitic infection. Clinostomum sp. was found only in C. gariepinus and C. pachynema from Ogun River.

Key words: Sharptooth catfish, Clarias pachynema, helminth parasites, south-west Nigeria.