Macroinvertebrate metrics are helpful tools for the assessment of water quality and overall aquatic ecosystem health. However, their degree of sensitivity and the most reliable metrics for the bioassessment program development are very poorly studied in Togo. This study aimed to test the sensitivity of metrics calculated at the family and genus levels. A total of 21 water quality parameters and macroinvertebrates' data were collected during three periods at 20 sampling sites within the Zio River. The canonical correspondence analysis (CCA), factor analysis (FA), and Spearman's correlation analysis were conducted on water quality parameters and macroinvertebrates' data. The results reveal that macroinvertebrate structure and composition were affected by water quality parameters related to human disturbances. In this study, three groups of macroinvertebrate communities were identified including sensitive taxa such as Ephemeroptera, Plecoptera, Trichoptera, and Odonata (EPTO) taxa; the resistant or resilient taxa such as Oligochaeta, Hirudinea, Diptera, and Pulmonates (OHDP) taxa; and tolerant taxa such as Prosobranchia, Bivalvia, Lepidoptera, Heteroptera, and Coleoptera (PBLHC). All the 13 macroinvertebrate-based metrics were found to be sensitive in the detection of water quality and human disturbance gradients. However, metrics related to EPTO and the tolerance measure [multimetric index of the Zio River basin (MMIZB), Average Score per Taxon (ASPT), and Biological Monitoring Working Party (BMWP)] are the most robust in discrimination of pressure gradients. This study reveals that macroinvertebrates are sensitive and can be used for the bioassessment program development at the order, family, or genera taxonomic level.

Biofloc technology (BFT) systems have been driven towards increased sustainability in the last decade. BFT depends on maintenance of the optimal carbon-to-nitrogen (C/N) ratio through supplementation with organic carbon sources. The types of carbon sources and addition strategies are critical considerations in BFT systems. Thus for the purpose of this review, a thorough search of the literature was conducted to gather relevant information from reliable sources, ranging from reputable journals to books and useful reports in the field of BFT. Keywords used for the literature search include: 'biofloc technology systems', 'carbon sources', 'solid carbon sources', 'effects of carbons sources', 'carbon source addition strategies', 'nutritional quality of bioflocs', 'carbon sources and water quality', 'C/N ratio in BFT', and 'carbon sources and bacterial community'. Among the several peer-reviewed articles, books and technical reports consulted, 147 (dated from 1987 to 2020) were relevant for the preparation of this review. The current review thus examines the subject of supplemental carbon sources in BFT systems and discusses the various effects of their application with respect to the culture organism, microorganisms, water quality and the nutritional quality of flocs. The benefits and challenges associated with the types of carbon sources used in BFTs are also presented. Suggested organic carbon sources and their addition strategies are provided, and further research directions are proposed.

Fish marketing has become an important trade in Ghana due to the increasing appreciation of the

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Length-weight relationship and condition factor have severalapplications on fish biology, physiology, ecology and fisheries assessment. A six-month study was conducted from November 2013 to April 2014 to determine the length-weight relationship and condition factor of four major cichlids namely Oreochromis niloticus (Nile tilapia), Hemichromis fasciatus (Banded jewelfish), Sarotherodon galilaeus (Mango fish) and Tilapiazillii (Red-belly tilapia) to fill a knowledge gap and provide useful information for fisheries management and conservation in the Golinga reservoir using the length-weight based model. Samples were collected twice every month with gillnets from commercial fishermen. The length-weight relationship had a strong positive correlation (r>0.8) for the four species. Oreochromis niloticus exhibited isometric growth (b = 3.07) whilst Hemichromis fasciatus (b = 2.81), Sarotherodon galilaeus (b = 2.91) and Tilapia zillii (b = 2.75) showed negative allometric growth. Mean condition factor (K) values were greater than one (3.66-4.88) for all the species and varied monthly. The study provided new information on lengthweight parameters for the four cichlids.

Journal of Coastal Zone Management AbstractMigration of fishers and fish workers is common in Africa. It affects the ways the people use and manage natural resources. This paper examines and reviews fisheries driven human migrations in the Gulf of Guinea and offer insight into the developmental implications underlying the immigrant and emigrants fishing activities. Fisheries driven human migration has deep historical in the Gulf of Guinea. It probably started in the sub-region before 15 th century. With most fisheries being small-scale, they are exploited under some sort of open access regime, sometimes enforced by modern governments, even though traditionally social mechanisms may have existed to restrict such access. It was realized that migration has both positive and negative effects on communities of destinations as well as migrants' home countries. Migrants contribute to the GDP of their destination countries and also support their families back. There have been conflicts as results of migrants fishing and in some cases resulted in political interferences. Migrants have limited privileges in some destinations. Migrants in some cases have no rights to own a land. Drawing on some of the generalities across the twelve countries that make up the Gulf of Guinea, Ghana, Cote d'Ivoire, and Nigeria are documented and perceived to have had major fisheries-driven human migrations in the sub-region. Traditionally, it is assumed that population is the main driven force behind migration. However, it observed that fisheries-related human migration has other main triggers. Seasonality of fisheries resources due to climate changes and upwelling regimes along the hot spots of Gulf of Guinea coast is possibly the most significant cause of fisherfolks seasonal migration which normally last for a period of 6 months. Socio-economic standings and political stability are major determining factors of long or permanent fisheries-related migration. Long-term migration of fishers spans over years. Fisheries driven migration is male-dominated and it has a clear gender-labour division in the sub-region. The few women who migrate with their husbands are mainly fish processors and fish mongers. The prospects for continued fishers and fish workers migration is high and it anticipated that seasonality of different fisheries regime will dictate the pace tempospatial dynamics of the fisher folks mobility. As there is no clear sign of a halt to fisheries related-human migration in the Gulf of Guinea, the need to raise public awareness and to improve knowledge on the danger of HIV/AIDS on their household and livelihood among fisher folks is also crucial.

Phytoplankton constitutes the primary producers of aquatic ecosystems and represents the food chain base that supports the commercial fisheries of most water bodies. Nowadays, there is lack of information on phytoplankton assemblages of most reservoirs in Africa. To contribute with this knowledge, this study was carried out to determine the density and diversity of seasonal variations of phytoplankton species in the Bui dam area of the Black Volta, during the pre-(2011) and post-impoundment (2012) periods. For this, a three-level stratified random sampling approach was adopted for 22 months. Phytoplankton samples were obtained by towing a 0.5m diameter phytoplankton net (35μm mesh size and 0.25m 2 mouth surface area) from a non-motorized canoe through a distance of about 100m against the current from downstream to upstream of the river. In 2011, 35 species of phytoplankton belonging to four classes, Bacillariophyceae (7.6%), Chlorophyceae (43%), Cyanophyceae (48.6%) and Euglenophyceae (0.8%) were identified. In the 2012 sampling, 18 species belonging to three classes, Bacillariophyceae (2.2%), Chlorophyceae (26.1%) and Cyanophyceae (71.7%) were observed. A total of 17 species of phytoplankton, including Gyrosigma sp., Surirella sp., Carteria sp., Chlosterium sp., Chlorogonium sp., Coelastrum sp., Cosmarium sp., Volvox sp., Chroococcus sp., Coelosphaerium sp., Rivularia sp. and Spirulina sp., were absent during the late post-impoundment period. Mean monthly total phytoplankton abundance decreased from June (7 384 cells/m 3 ) to August (106cells/m 3 ) in 2011. In 2012 however, mean total phytoplankton decreased from February (1 237cells/m 3 ) to August (4cells/m 3 ). The results also showed that variations occurred between seasons among some phytoplankton groups. The dry and pre-wet seasons had significantly (p<0.05) higher mean phytoplankton abundance than the wet season during the 22 months of sampling period. The biotic indices of Shannon-Wiener (H 1 ) were homogenously distributed in the four hydrological seasons of the two years. The phytoplankton groups, Bacillariophyceae, Chlorophyceae, Euglenophyceae and total phytoplankton differed significantly (p<0.05) between the pre-and post-impoundment periods. The total phytoplankton was also significantly (p<0.05) higher in the upstream station than the downstream station indicating the impact of the impoundment on the downstream ecology. Hence, river management strategies should be implemented by hydro-biologist to lessen the impact of the dam on the downstream ecology. Rev. Biol. Trop. 63 (1): 13-22. Epub 2015 March 01.

Professional fishing and fisheries quota systems can affect women and men differently, yet gender analysis of quota systems is rare. In this article, we use a feminist framing and a mixed methods approach to examine the long-term gendered effects of the introduction of the 1990 quota system in Norway. Using statistics from the National Fishery Registry and the Directorate of Fisheries, we found that the number of women and men registered as fishers has declined since 1990 (an overall decline of 59%). Over this period, men have consistently outnumbered women among registered fishers (2.7-3.2% women), among boat owners (2.23% women in 2017) and particularly among owners of larger boats (> 11 m), which can have multiple quotas (0.35% women in 2017). However, changes in the age and geographic location among women fishers reflect changes to fisheries overall, as well as highlighting the gender-blind entry barriers that disproportionately impact women. In addition, contextualising statistical data with participant interviews conducted in North Norway, especially in Finnmark, enables us to examine more closely why the gender gap remains. This mixed method approach also identifies changes women and men working in fisheries have undergone, while also addressing women fishers' political efforts to improve gender equity in Norwegian fisheries. Our study contributes to a more nuanced understanding of Norwegian coastal fishing, and particularly women's small but significant presence.