Fishery management plans and the development of artisanal fisheries in Nigeria: a review

Management of natural resources all over the world is of paramount importance to their sustainability in developing countries like Nigeria, there is less emphasis on proper management especially of fishery and other aquatic resources due to lack of sensitization and enlightenment of the rural dwellers who are closer to such natural resources. The main thrust of this review is to examine the management plans for Nigerian freshwater bodies (rivers and lakes) and the impact of such plans on the artisanal fisheries development in Nigeria. From the on-shelf information gathered there is scarcity of information on the management of Nigerian freshwater body's information available indicates that there is the traditional fisheries management and the government legal approach in form of fisheries Laws and Regulations. However, these management techniques are poorly carried out since there is a poor follow-up. Appreciable impact of fisheries management introduced on Kanji Lake by the Nigerian-German Kanji Lake Fisheries Promotion Project (NGKLFPP) between 1993 and 2001 proves worthwhile as this introduced some management measures such as implementation of fisheries Laws and Regulations, the ban of obnoxious fishing methods, introduction of fishing license, constitution of a management unit and appointment of liaison fishermen. Within the operative years of the project a lot of success was achieved and it is recommended that the approach in Kainji should be replicated in other freshwater bodies in Nigeria to alleviate poverty in the rural poor fishing communities

Strategic partnership of stakeholders: a veritable tool for sustainable fishery resources in Nigeria

Fishery resources are very important resource from the aquatic environment to the Nigerian economy. Stakeholders involvement in its management is highly important therefore, this paper proposes two frameworks against which sustainable fishery should be based, vis-a-vis stakeholders participation. The paper showed that decision-making involving stakeholders would enhance the goals of sustainable fishery development and create unity of purpose among various stakeholders

Fishery resource surveys: beyond length-weight relationship models

Fisheries resource surveys are regular management tools for rational exploitation of commercial fisheries. In a growing number of cases, the use of these resource surveys has been largely restricted to assessment of the relative well being of fish stocks and the potential yields of such fisheries. This paper seeks to demonstrate that the data from such surveys can also be easily used to evaluate species diversity of such fisheries, both in terms of species richness and equitability of distribution. Using published data on two freshwater and two marine fisheries as case studies, Shannon-Wiener Diversity Function and Simpson's Index were computed for each of these fisheries. These biodiversity indices gave a deeper insight into the environmental status of each of these fisheries, beyond what the length-weight relationship models can reveal. Generally, while the marine fisheries showed more species richness, the freshwater fisheries apparently had more stable and equilibrated fish communities

Rents drain in fishery: the case of Lake Victoria Nile Perch fishery

Many fisheries are potentially very valuable. According to a recent report by the World Bank and the FAO (2008), global fisheries rents could be as high as US$ 40-60 billion annually on a sustainable basis. However, according to the report, due to the “common property problem”, most fisheries of the world are severely overexploited and generate no economic rents. The Lake Victoria Nile perch fishery could be among the most valuable fisheries in the world. Unfortunately, also this fishery has fallen prey to the common property problem with excessive fishing effort, dwindling stocks and declining profitability. As a result, there is a large and growing rents loss in this fishery (compared to the optimal) reducing economic welfare and economic growth opportunities in the countries sharing this fishery. As in other fisheries, the biological and economic recovery of this fishery can only come though improved fisheries management

Survey of the shrimp stocks of the Sierra Leone inshore shelf : a summary report outlining objectives, observations and recommendations on the status of the Sierra Leone shrimp fishery

This report gives the species and catch-rates per hour of some commercial shrimp species caught in the course of a short survey of inshore shelf fishing grounds. Species seen in significant quantities were: Parapenneopsis atlantica, Parapenaeus longirostris, Penaeus kerathurus and Penaeus duorarum notialis

A rapid and simple method for the determination of Formaldehyde in Fishery Products

The content of free formaldehyde (FA) in minced fish muscle was measured by the following procedure: A mixture of minced fish muscle and water was deproteinized by means of the Carrez reagent. The FA content of the filtrate was determined reflectometrically using the Reflectoquant test strips and the RQflex. The results agreed well with the colorimetrically (Nash test) measured FA content. Der Gehalt an freiem Formaldehyd (FA)in Fischerzeugnissen wurde mit folgender Methode bestimmt: Zerkleinertes Fischfleisch wurde mit Wasser homogenisiert und mit Carrez-Reagenz enteiweißt. Der Formaldehydgehalt des Filtrates wurde reflektometrisch unter Verwendung von Reflectoquant-Teststätbchen und des RQflex ermittelt. Die Ergebnisse stimmten gut mit kolorimetrisch (Nash Test) gemessenen FA-Gehalten überein.

The story of a small trout fishery

This article relates the experience of creating and developing a fishery in southern England. The fishery was made from a small stream which dries up from time to time, and marks the boundary between a Sussex farm and a large coniferous forest. The preparation of the site and creation of the impoundment are described, and early experiences outlined. The fishery was expanded in later years, as a result of its popularity, and records of its use by anglers are illustrated. The performance of the fishery is measured in terms of "good fish" (more than 675 g) taken, and their number has increased from 81 in 1984 to 226 in 1991. The aquatic plants, invertebrates, and birds of the fishery are discussed, as are the natural predators of the fish.

A decade of studies at Loch Fleet, Galloway (Scotland): A catchment liming project and restoration of a brown trout fishery

Loch Fleet is a small upland lake in the hills of Galloway in southwest Scotland. In the 1970s the waters of the loch became more acidic and a brown trout fishery failed. This account summarises an experimental project, the "Loch Fleet Project" initiated in 1984, designed to reverse acidification of the loch by liming parts of the catchment. Liming about 40% of the catchment in 1986 and 1987 raised the pH and calcium levels, and reduced toxic aluminium concentrations. The improved conditions had been maintained up to 1994, but water in the loch, and its principal inflow stream, is now falling close to the desired threshold of quality. After liming, restocking with local strains of trout in 1987 was successful, and a self-recruiting population became established within 2 years. Recruitment is highly variable, however, and was attributed to severe spring conditions and the limited spawning capacity of the nursery stream, rather than to water quality.

The blackback flounder and its fishery in New England and New York

A decline in the abundance of blackback flounders, together with the withdrawal of vessels from this fishery, has resulted in a lowered catch in recent years compared to the peak period 1928 through 1931. Data obtained from U. S. Fish and Wildlife Service Hatchery catch records and from fishermen's log book records show a drop in abundance of 63 per cent from the early 1930's to the present in the Boothbay Harbor region and of 31 to 40 per cent in the area south of Cape Cod. Information on the early life history and distribution of young blackback flounders and the size and age composition and distribution of fish subject to the commercial and sport fisheries indicates that the young are the product of local spawning and that the sport and commercial fisheries draw on a resident stock of primarily adult fish.

The relationship between boat size and fish catches in the gillnet fishery of Lake Victoria, Uganda

The number and size composition of gillnets, fishing grounds, and the quantity and composition of fish catches were related to the size of fishing boat. The overall number of gillnets per boat increased from 20.9 + or - 2.3 nets in 5-6 m long boats to 88.6 + or - 11.8 nets in 11-12 m long boats. The proportion of large mesh sizes, + or more than 127 mm, also increased from 40% in 5-6 m long boats to 100% in boats longer than 10 m. Fish catches are related to the size of boat and this should be considered when formulating management guidelines of the lake's fishery. Promotion of large fishing boats 8 m or longer and restriction on the number and/or mesh size of gillnets of smaller boats could increase ecological and socio-economic benefits.

The status of the artisanal fishery of Lake Victoria, Kenya, with notes on improvements to the catch data collection system

Catch and effort assessment surveys have been used to assess trends in fish landings in Kenyan waters of Lake Victoria since 1976. Landings reached a maximum of 200000 t annually in 1989-1991 as Nile perch, Lates niloticus (L.), catches increased due to an expansion in stock size and increased fishing effort. CPUE peaked at 180 kg boat day-1 in 1989 and decreased thereafter with increasing effort. By 1998 total Nile perch catches were half those at the beginning of the decade despite increased effort. Catches of Rastrineobola argentea (Pellegrin) have levelled off despite increased effort.

Invertebrate communities in northern Lake Victoria, with reference to their potential for fishery production

The zooplankton and macrobenthic communities of Lake Victoria were sampled by lift net and Ponar grab, respectively. The zooplankton comprised copepods and cladocerans, rotifers and aquatic insect larvae. Most taxa exhibited wide distribution in the lake, with the exception of rotifers which were rare in deep offshore waters. The main components in the macro-benthos were chaoborid and chironomid larvae and molluscs. Caridina nilotica (Roux) and other groups were rare in the samples. Zooplankton density ranged from 100000 or more to 4 million ind. m2 and increased from the shallow inshore to deep offshore waters. Numerical dominance of cyclopoids and nauplius larvae was a common feature at all stations sampled. Most macrobenthic taxa were also widely distributed, although chaoborid and chironomid larvae were rare in the samples. Rastrineobola argentea (Pellegrin) and larval Lates niloticus (L.) ate mainly cyclopoid copepods, while cichlids showed a strong preference for adult insects. High ecological stability of the cyclopoids, and the zooplankton community in general, despite radical ecosystem changes in recent years, coupled with what appears to be high predation pressure, offers good prospects for the pelagic fishery in the lake.

The regulators and the regulated: fisheries management, options and dynamics in Kenya's Lake Victoria fishery

The study divides the history of the fishery into five 'regulatory periods': the pre-colonial fishery (pre-1901), the colonial fishery (1901-1963), the post indipendence fishery (1963-1980), the Nile perch 'boom' years (1980-1989), and finally the fishery in the 1990's. Within each of these periods, the nature of and the relationship between, formal and informal regulations differs and changes with time. In the pre-colonial period, the outcome of formal and informal regulations largely sustained the fishery in a productive and species diverse state. However, at no time since then have formal regulations worked, with the result that the nature of production from the fishery changes over time and is dependent on a number of factors, amongst which the most important are effort level increases, technological introductions, species introductions, changes in regional and national job markets, the change from community-based controls to state-based controls within the fishery, and finally, considerable changes to the fish markets.

On statistical treatment of the results of parallel trails with special reference to fishery research

Parallel trials form a most important part of the technique of scientific experimentation. Such trials may be divided into two; categories. In the first the results are comparable measurements of one kind or another. In the second the data consist of records of the number of times a certain 'event' has occurred in the two sets of trials compared. Only trials of the second category are dealt with here. In this paper all the reliable methods of testing for significance the results of parallel trials of a certain type with special reference to fishery research are described fully. Some sections relate to exact, others to approximate tests. The only advantage in the use of the latter lies in the fact that they are often the more expeditious. Apart from this it is always preferable to use exact methods.

Size composition of the catches of the pink shrimp Penaeus duorarum notialis in the shrimp fishery of Sierra Leone

Measurements were taken of size distribution of P. d. notialis collected off Sierra Leone over a period of six months from October 1977 to March 1978. From the frequency distribution curves it is observed that the curves for male shrimps show only one or two major modes, which show prominence between 12.5 and 14.1 cm of total length. Females mostly exhibited size groups with three or four different length ranges and occasional occurrence of 1 to 5 modes. These size groups were observed to show continuous changes. No one group could be said to be permanent. The point of entry into the fishery of male shrimps was found to be at an average total length of 10.5 cm, while females did so at 11 cm. Sex ratios in the different samples were usually 1:1 but in one case the males were more numerous by 2:1 and in four other samples females were significantly preponderent. These departures from the 1:1 ratio may have been artificially created by sorting of the catches on board the ships.