ABSTRACT:A baseline study of the intertidal and subtidal zones of the Andoni flats was conducted to determine the basic physical and chemical characteristics of the sediment. Sediment characteristics revealed sandy to loamy (muddy) sand soils with pH of 4.09 to 5.04. Values of organic carbon varied from 0.17% in the sandy soil to 3.01% in the muddy sand soil. Other parameters determined include organic matter which varied between 0.29% and 5.22%, conductivity with values varying from 1120µScm -1 to 1800µScm -1 and water absorbency with values ranging from 21.74% to 43.73%. Particle density, bulk density and porosity of the sediment were also determined for the flats. @JASEMThe physical and chemical characteristics of any water body are of ecological significance especially in estuarine ecosystems that are prone to daily tidal physicochemical fluctuations.Studies on basic physicochemical characteristics carried out in various rivers, lagoons and estuaries in Nigeria have focused on the water quality parameters of the rivers' water columns (Akpan and

Physicochemical characteristics of the interstitial fluid of the sediment of the intertidal and subtidal zones of the Andoni flats were studied. The results for the interstitial fluid showed low dissolved oxygen levels (0.1 -1.3mg/l), high temperature values (26.2 -32.4°C), wide salinity range (8 -21ppt) and near neutral pH (6.26 -7.76) across stations. Sampling duration was from January 1999 to December 2000 covering both wet season (AprilOctober) and dry season (November -March). The implications of the effects of fluctuating environmental variables on in-fauna inhabiting sediment are discussed. @JASEMIn recent times studies on the water quality of estuaries and coastal systems in Nigeria have received some level of increasing attention (Akpan and

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The investigation of recruitment pattern and catch per unit effort of the black tiger shrimp (Penaeus monodon) was conducted from March 2012 to February 2013 in Andoni River System, Niger Delta region of Nigeria. Total weight and length of sampled P. monodon, number of fishers, fishing duration and temperature were sampled monthly. Total weight of P. monodon landed, number of fishers and fishing duration was used to determine catch per unit effort in kg/man/h. The recruitment pattern was analyzed using the length frequency data of the stock. The result shows that recruitment pattern was continuous and higher during the rainy season, that is from May to October. Catch per unit effort was lowest (46.09Kg/man/h) in January and highest (78.11 kg/man/h) in September. Mean temperature ranged from 27±0.32°C to 31±0.89°C which was suitable for the stock. A positive moderate correlation existed between recruitment and catch per unit effort (r = 0.50056) while a positive weak correlation occurred between recruitment and temperature (r = 0.21102). It is concluded from the study that a rise in the recruitment of P.monodon translated into a rise in catch per unit effort and that temperature was not the only factor necessary for recruitment.

Length and weight measurements of a population of 513 specimens of trap-caught Chrysichthys nigrodigitatus harvested between January and July (excluding May), 2010 were analyzed using the following softwares; FiSAT (Fish Stock Assessment Tool) and Popdyn JFB.xls. Results of the sampled population gave a total length range of 18 to 95 cm, L max (113.8 cm), L∞ (116.8 cm), L m (60 cm), L opt (75.9 cm), and weight; 100 to 12,000 g indicating the promising nature of this trap fishery to make significant contribution to food security and socio-economic development if effective management of the fishery can be developed and enforced. The high percentage of occurrence (76%) of length at first maturity Lm is suggestive of the need for more confirmatory research that can lead to the enactment of a limited access fishery law in the form of closed season and closed area along this river system. The negligible occurrence of small sized individuals from catches indicated the appropriateness of this cylindrical metal trap as gear for the sustainable exploitation of C. nigrodigitatus fishery.