Growth, mortality, recruitment and relative yield per recruit of Sarotherodon galilaeus galilaeus from Lakes Doukon and Togbadji were studied. Data on total length, total weight and sex were recorded on a monthly basis between January and December 2013 for S. g. galilaeus captured by local fishers. The estimated asymptotic lengths L" were 26.2 and 23.6 cm for Lakes Doukon and Togbadji, respectively, while the growth rate K was 0.73 in Lake Doukon and 0.87 in Lake Togbadji. Estimates of fishing mortality, 0.27 and 0.47 y -1 for Doukon and Togbadji, respectively, were low relative to natural mortality, 1.51 and 1.74 y -1 , respectively. Sizes at first sexual maturity were 12.8 and 13.2 cm for females and males, respectively, in Lake Doukon, and 11.5 and 12.4 cm for females and males, respectively, in Lake Togbadji. The size at first capture was estimated at 13.3 and 12.7 cm for Lakes Doukon and Togbadji, respectively, which, in the light of the size at maturity estimates, indicates that fish spawn at least once before capture. The current exploitation rates of 0.15 for Lake Doukon and 0.21 for Lake Togbadji suggest that their stocks of S. g. galilaeus are not overexploited in either lake.

Sand is a useful resource for the development of any society. As such, the issues related to its extraction are everywhere present in Benin, especially in the southern part of the country. For the purposes of eventually characterizing those issues, the present study is undertaken with a focus on inventorying estuarine and lagoonal ecosystems which are subjected to sand mining in southern Benin. The study area covers both the Eastern Complex and the Western Complex. The Eastern Complex includes the Porto-Novo Lagoon and the Ouémé River delta; while the Western Complex includes the Coastal Lagoon, the Aheme Lake along with its channels, and the Mono Basin. The method used in this study is a systematic inventorying of all known and documented sites as kept on record with relevant state offices in charge of the management of those resources. Then, the data were completed by combing the whole area for direct census observations and field interviews with stakeholders. All inventoried sites have been geo-referenced using a GARMIN GPS and their surface areas have been established. To date, 43 sand-mining sites have been identified, of which 29 are located in the Oueme Delta and in the Porto-Novo Lagoon, 8 are in the Coastal Lagoon, and 6 are in the Aheme Lake and its channels as well as in the Mono River basin. The areas are small in the Oueme Delta, where extraction is mostly manual, but get to be more than 89-ha wide in other places such as the Coastal Lagoon where the process is rather mechanized.

Crabs are an important biological component of the West African lagoon fauna and are exploited by fishing communities. This paper presents a synthesis of the current understanding pertaining to the diversity, biology and exploitation of these crabs in order to identify promising research paths for this zoological group. A literature review was done. Thirty-two species belonging to thirteen families and twenty-three genera have been indexed by previous investigators and we plan on making use of this information in defining future research direction. The biology of crabs has been the subject of much research focused on Callinectes amnicola (Rochebrune, 1883) species. C. amnicola is an omnivorous species whose males are known to mature between 63 and 105 mm shell width, while females mature between 83.5 and 116.2 mm shell width. Fertility varies from 0.47 to 4.8 million eggs per female. However, exploitation parameters for this species in various lagoons are not available. A research direction geared towards establishing a new and thorough inventory along with currently nonexistent but relevant exploitation parameters will go a long way in defining sustainable management measures for these crab species.

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