A study was conducted to investigate genetic diversity and population structure among populations of Nile tilapia Oreochromis niloticus (Cichlidae) in the Volta Lake of Ghana using microsatellite markers. Four hundred (400) fish specimens were obtained from nine naturally occurring subpopulations and one selectively bred strain, 'Akosombo strain'. These were characterized using 15 microsatellite loci. Twelve of the loci were multi-allelic, producing 2 to 11 alleles per locus while the effective number of expected alleles (Ne) ranged from 2.030 to 2.855. The observed heterozygosity (Ho) and expected heterozygosity (

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This study described some aspects of the reproductive biology of Blackchin tilapia (Sarotherodon melanotheron, Cichlidae) from Brimsu reservoir. A total of 457 specimens were sampled using a monofilament gill net of mesh size 25 mm from September, 2009 to September, 2010. Standard length for the species ranged between 7.5 and 17.6 cm, with both males and females having a unimodal modal length of 10.0 to 10.9 cm. The length at sexual maturity (L 50) was 11.26 and 11.34 cm for males and females, respectively. The pattern of fluctuation in gonadosomatic index indicates that the species had an extended spawning season starting from February to August.

This study is the first to provide information on the parasite fauna of Sardinella maderensis along the coasts of Benin and Ghana, and the first to investigate the potential use of parasites as biological tags in fish population studies in the area. It may thus serve as a starting point for upcoming studies. From February to June 2021, a total of 200 S. maderensis were sampled from the fishing port of Cotonou (Benin) and the Elmina landing site (Ghana). The prevalence and abundance of each parasite were recorded. The following are the outcomes of this study: Parasite species, such as Parahemiurus merus, Mazocraeoides sp. and Hysterothylacium fortalezae, were recorded along the coasts of Benin and Ghana, while Anisakis sp(p). and Tentacularia coryphaenae were only recorded along the coast of Benin. Parahemiurus merus was the most prevalent and abundant among all the parasites recorded. Anisakis sp(p). and T. coryphaenae were selected as having potential in the stock identification of S. maderensis. Both parasites were only recorded along the coast of Benin at a low prevalence. As a result, examinations of more S. maderensis from each location for these parasites may justify their use in stock identification studies.

Aquaculture development has been identified as a key process to meeting the demand for cheap and readily available source of protein. The resultant has been the springing up of cages along the Volta Lake with most farmers producing Nile tilapia. However, the sector faces an array of challenges which needs urgent attention. A study was undertaken to ascertain the production systems and dissemination channel of Nile tilapia among farmers along selected coastal regions in Ghana. A survey of 190 farmers representing the fish farming community in the area was used -these comprised 187 males and 3 females. Pond culture and cage culture were the most common holding facilities used constituting 58.8% and 28.9% respectively. The production of all-male tilapia was popular among farmers and constituted 66.8% of production, while the production of mixed sex tilapia formed 25.8 %. The study revealed that the high prices of fish feed and lack of access to finance were the top ranking financial challenge facing fish farmers in the area corresponding to 73.2% and 51.1% of the response respectively. Other factors such as distance to hatchery and price of fingerling was a significant factor affecting the choice of source of fingerling for stocking (P<0.05) for farmers who used dugout ponds. There was no clearly laid down protocol for dissemination the tilapia. Farmers (16%) who undertook dissemination directly supplied fingerlings and broodstock to other farmers. Investment of capital into tilapia production can improve productivity and profitability.