Protozoa Most of the commonly encountered fish parasites are protozoan. With practice, these can be among the easiest to identify, and are usually among the easiest to control. Protozoan is single-celled organisms, many of which are free-living in the aquatic environment. Typically, no intermediate host is required for the parasite to reproduce (direct life cycle). Consequently, they can build up to very high numbers when fish are crowded causing weight loss, debilitation, and mortality. Five...
Fishery development is a process towards achieving the full potential of the sector through growth and improvement. Fishery development is also defined to include the expansion of fishing effort, improvement in post-harvest technology, marketing and transportation of fishery products as well as the provision of infrastructure and other related facilities. In fisheries, development may be defined as a process of change through which sustainable and equitable improvements are made to the qualit...
Colour and Turbidity: Often it is the colour of freshwater or how clear or hazy the water is that is the most obvious visual characteristic. Unfortunately neither colour nor turbidity are strong indicators of the overall chemical composition of water. However both colour and turbidity reduce the amount of light penetrating the water and can have significant impact on algae and macrophytes. Some algae in particular are highly dependent on water with low colour and turbidity. Many rivers draini...
The term “fish” most precisely describes any non-tetrapod craniates (that is an animal with a skull and in most cases a backbone) that have gills throughout life and whose limbs, if any, are in the shape of fins. Unlike groupings such as birds and mammals, fish are not a single clade but a paraphyletic collection of taxa, including hagfishes, lampreys, sharks and rays, ray-finned fishes, coelacanths and lungfishes. A typical fish is ectothermic, has a streamlined body for rapid swimming, ...
Nigeria occupies between 4 0 16’ – 130 52’N and longitude 2 0 49 – 14 0 37’E and a coastline of approximately 850km bordering the Gulf of Guinea in the Atlantic Ocean. Consequently, Nigeria is a maritime state with the establishment of the Exclusive Economic Zone (EEZ) of 200 nautical miles in 1978. The major geomorphologic features of the Nigeria continental shelf include the Avon, Mahin and Calabar Canyons. Other geomorphic features are sand banks in the inner continental shelf es...