Management Strategies and Uses in Fisheries Management

June 24, 2023 Agric4Profits

Fisheries management is the rational exploitation of fisheries resources in a way that economic benefits accrue to man and resources are protected and conserved. Fisheries management involves a lot of systematic procedure in ensuring the continuous availability of the fish resources. Fish production is however, mainly from three sub-sectors; namely,

(a) Industrial/commercial fisheries

(b) Artisanal fisheries and

1. Industrial Fisheries

This involves the use of highly mechanised techniques and fishing gears refer to as fishing trawlers or fishing vessels, most of which are imported. The skill and techniques involved in this fishery is quite high and more advanced than the artisanal fisheries. The catch per unit effort and the profit margin derived from fishing is high.

2. Artisanal/small Scale Fisheries

These are fishing operations practiced by small scale fishermen in the rural communities along the coast line and the boundary of inland water bodies e.g. dams, lakes, rivers etc.

They make use of small-medium sized canoe usually between 3-10 metres. The small scale fishermen in
Nigeria make use of simple, outdated or crude fishing gears such as fishing nets, traps of various sizes and shapes, beach seinenet, purse seine net, damming of the water etc.

The labour involved in fishing is far beyond the financial return. The catch per unit effort is significantly low and the fisher folks face many social problems. Despite the social problem of small scale fisheries in Nigeria, it accounts for over 80% of the domestic fish production.

3. Aquaculture

Aquaculture has been defined in a number of ways. It has been called “the art of cultivating the natural produce of water”, the raising or fattening of fish in enclosed ponds. It is the rearing of aquatic organisms under controlled or semi controlled conditions.

Both fresh and marine water fishes are reared in well designed and managed ponds (enclosures). Aquaculture practices are yet to find its full feet. It has only been contributing about 5% of domestic fish production in Nigeria.

Strategies Used in the Management of Fisheries

Successful management of an aquatic ecosystem requires fundamental information about the state, properties and dynamic interactions among the various components of the system. In Nigeria, the immediate need for food production in the form of fish flesh is paramount, especially in the face of burgeoning populations.

This implies that procedures and plans must be provided to ensure continuous availability of fish resources. Management procedures often employed in commercial fisheries and small scale fishermen are similar because they involve the utilisation of the open natural waters.

Management of the resources of capture fisheries is very cumbersome because man does not have direct control over the activities and yield of the resources. However, certain resources such as fish yield assessment, fish stock assessment, determination of maximum sustainable yield (MSY), age determination, and population dynamic studies are important for management purposes.

Management measures that are usually taken to increase fish production in open water bodies include;

(i) Quota system

(ii) Regulations of the fishing gears

(iii) Limitations on catch by individual fishermen

(iv) Limitations of time of fishing.

(v) Limitations on size of fish caught

(vi) Limitations on area being fished

(vii) Limitations on species caught

(viii) Open and closed seasons

1. Culture Fisheries

Unlike capture fisheries, culture fisheries enjoy some/high level of control over the culture medium depending on the enclosure being used. The overall objective of any management measures is to increase fish production.

Some of the measures that must be taken in aquaculture include the following;

(i) Proper site selection (Good soil, topography and water)

(ii) Well designed and constructed ponds

(iii) Selection of fish species

(iv) Choice of culture system (polyculture or monoculture)

(v) Provision of good feeds

(vi) Water quality management

(vii) Proper management of health and diseases

(viii) Harvesting the fish

2. Culture System

Culture system refers to the medium in which the fish will be raised. Culture systems can be categorised into three major system groups: open, semiclosed and closed. Each has its special characteristics, advantages and disadvantages.

The choice of the system is largely a function of the organisms to be grown and the resources and ideas of the fish farmer.

3. Open Systems

These are the oldest of the aquaculture system. Open system farming is the use of the natural environment as the fish farm. An open system does not require water to be pumped out of a sea or a lake, rather, the fish to be cultured are kept in the sea or lake. Examples of open system include dam beds, rafts and fish cages.

Open systems are often leased from government agencies. Capital expenses are generally low and there is less management than in the other systems. However, predation and poaching could be a problem. The farmer also has less control over the environmental conditions, so the rate of growth and uniformity of the fish varies if compared to other systems.

4. Semi-closed Systems

Semi-closed system is the most popular method of culture for many types of organisms. Water is taken from a lake, bay, well or other natural source and is directed into a specially designed facility.

Semiclosed system includes ponds, raceways, tanks etc. It offers an advantage over open systems in that they allow greater control over the growing conditions.

A greater production per unit area is possible in addition to the crop being more uniform. This is because temperature, water volume and amount spent can be regulated. Prepared feeds can also be used with such less waste and aeration can be increased simply.

This system is more expensive to develop and operate than open systems and it requires a more complex management scheme.

5. Closed System

Closed system is that culture system in which little or no water is exchanged and the water is subject to extensive treatment. These have made little impact on the commercial aquaculture industry, although some laboratory reports are very promising. Extremely high densities of fish can be raised under these conditions, if they are managed properly – the farmer has complete control over growing conditions.

Weather conditions are never a problem and harvesting is simple. Food and drugs can be added efficiently into the system. All these allow the fish to grow quickly and uniformly. A problem associated with close system is the re-used water and the great density of the culture fish.

Hence, the filtration/treatment system must be very good and the water must be pumped through these systems at a fairly high speed. Diseases outbreak could be a problem in a closed system. Examples of closed system include Water Recirculatory System (WRS) and flow through systems.

Read Also: Post-Harvest Handling of Fish and Marketing