Saturday, November 9, 2024
Fishery

Basic and Practical Objectives of Fish Management and Conservation

Regarding the basic and practical objectives of fish management and conservation, several authors and groups have defined the term conservation in different ways. Three of such definitions are given in this article.

Definitions of Conservation

There are many definitions of conservation given over the years by individuals or groups (Olver, etal.1995). A few of them are given here:

“The use of the natural resources for the greatest good of the greatest number of people for the longest time” (Pincot, 1947).

“Management of human use of the biosphere so that it may yield sustainable benefit to present generations while maintaining its potential to meet the needs and aspirations of the future generations” (International Union for the Conservation of Nature and Natural Resources, 1980).

“Management of human use of organisms or ecosystems to ensure such use is sustainable. Besides sustainable use, conservation includes protection, maintenance, rehabilitation, restoration and enhancement of populations and ecosystems” (World Conservation Union, United Nations Environmental programme and Worldwide Fund for Nature, 1991).

Principles of Conservation

The primary goal of fisheries management is to ensure the perpetuation of self-sustaining stocks of indigenous aquatic species and where possible to allow their sustainable use.

Aquatic ecosystems should be managed to ensure long term sustainability of native fish stocks. The key to conservation is sustainability of naturally producing wild stocks of native fish.

Stocks are the repository of genetic diversity within each species and are the building blocks of on which fisheries management is based. The sustainability of fish stocks requires maintenance of its supporting native community.

The sustainability of a fish stock requires the protection of the specific physical and chemical habitats utilized by the individual members of the stock population (Olver, 1995).

Objectives of Conservation

Several reasons have been given for the conservation of wild species of plants and animals. Conservation is important for economic, medical, scientific, ecological, aesthetic and recreational values of species.

Economic and medical importance of wild species – food crops and animals are sourced from the wild. Existing wild stocks are needed for producing improved strains.

Medicines from plant and animal sources, e.g. plant extracts derived for drugs e.g. antibiotics from microorganisms such as penicillin and tetracycline.

Wild species provide ecological services and are key factors in sustaining the earth’s biodiversity and ecological integrity.

They supply food, recycle nutrients, generate and maintain soils, produce oxygen and other gases, absorb pollutants, moderate the earth’s climate, regulate local climates and water supplies, reduce erosion and flooding, store solar energy, detoxify poisonous substances, breakdown organic wastes, control potential pests and disease carriers, make up the gene pool for future generations.

Aesthetic and recreational importance – They serve as sources of beauty and recreation.

Ethical importance – Species have rights to exist and each species has its intrinsic value unrelated to its usefulness to man.

Causes of Declining Fish Stocks

Basic and Practical Objectives of Fish Management and Conservation

Overfishing/overharvesting – The rate of fishing is greater than the ability of the stock to replenish or replace itself.

Habitat loss/destruction e.g. deforestation, sand filling of wetlands – swamps, mangrove forests for construction purposes and destruction of coral reefs by dynamite fishing.

Habitat fragmentation is a form of habitat destruction involving the removal or modification of the original habitat leaving only patches. It causes degeneration of biodiversity, disruption of life cycles, and isolation of some animals in islands of habitats.

Introduction of species create major problems such as predation; uncontrolled breeding because of lack of natural checks and balances, disruption of food chains, competition for space, nutrition, mineral resources and changes in ecosystems.

Read Also Fisheries Enhancement: Forms, Constraints and Reasons

Pollution (oil, industrial, etc.) of coastal areas and wetlands lowers habitat quality. Excessive release of chemicals over extended periods will poison habitats and spread out into food chains; cause loss of the aesthetic values of beaches due to unsightly oil slicks; damage to marine life, ecosystem changes due to species mortality and changes in food chains; decrease in fishery resources.

Trawling for fish disturbs the benthos.

Human population pressure.

Poor agricultural practices, e.g. destruction of watersheds, clearing of river banks and other critical areas cause silting of river beds and loss of water courses; excessive use of agro- chemicals cause problems of chemical persistence in the soil.

Biodiversity most Affected by Human Impacts

Human impacts on the environment such as habitat loss and pollution do not threaten all groups of biodiversity equally.

The most affected groups are the species with small population sizes, species with slow rates of population growth. Groups most susceptible to extinctions include:

Species at higher trophic levels such as large, rare animals with slow rates of population growth. They are very susceptible to over exploitation and habitat loss.

Local endemics which are species with restricted ranges and often threatened by habitat loss. Water development, pollution or habitat alteration can easily drive these species to extinction.

Species with small populations, e.g. many species at higher trophic levels have low populations. Habitat restrictions or fragmentation may reduce their populations to very low levels. Populations of species at very low trophic levels may also be very low in a habitat or region.

Large species have high metabolic demands, require large habitats and occur in low densities. The largest species within a group or of species sharing similar food sources (a guild) tend to be at high risk of extinction.

Species with poor dispersal and colonization abilities: Groups with narrow habitat requirements and species that cannot disperse easily to new habitats are at high risk of extinction.

Species with colonial nesting habitats are very susceptible to over exploitation or loss of breeding habitat.

Migratory species depend on suitable habitat along the migratory routes and in different seasons. Adverse habitat effects on migrant populations are very high and species with specialized feeding habits will fluctuate greatly.

Species with little evolutionary experience of human disturbance are more affected by human-induced perturbations

Conservation Methods for Fisheries

Cultural practices: These include societal beliefs, norms, values, and ethics. These provide checks and balances, e.g. attachment of some water bodies and their aquatic resources to certain deities and other superstitious beliefs, taboos and fines to offenders both in cash and kind

Legislation: Some legislation, e.g. Sea Fisheries Decrees (1971, 1972, 1992), Inland Fisheries Act (Decree 108, 1992) ban the use of poisons, pesticides, explosives, some types of nets and fishing gear such as fish fences.

Conservation and consumer education using face-to-face interactions, radio/television messages and advertisements. These create awareness on the needs to conserve fisheries. Consumers should be educated to reject the consumption of fry, fingerling and juveniles

Monitoring,control and surveillance: It is difficult to enforce laws, inland waters are not as well policed as coastal areas.

Stock assessment: For proper conservation measures to be carried out there is a need for stock assessment to know the available fish stocks.

Aquaculture could be encouraged to reduce the pressure on wild stock or capture fisheries.

Restocking operations (and other enhancement methods) can be explored to revive overfished stocks. Provision of correct fishing inputs to discourage the use of faulty fishing gear (Adeleye, 1993).

Major Issues in Conservation of Fisheries

According to Shepherd (1993), there are several key issues in the conservation of fisheries such as:

Management and conservation of fish stocks are necessary because economic forces do not usually lead to satisfactorily stable stocks.

Fishing increases death rate of fish, reduces the size of stock and lowers the catch per unit effort and the profitability.

An unregulated fishery will give poor profitability and stocks fall below the maximum sustainable yield. There is also the risk of poor recruitment due to the small number of spawning stock.

Conservation measures are needed permanently not only while the stocks are in poor shape. Conservation measures are designed to reduce the death of fish due to fishing. If discontinued when the fishery recovers, fishing would increase again depressing the population again.

Technical conservation measures, e.g. mesh size regulation are not usually enough but should be used with direct conservation measures e.g. limits on catches and or fishing effort.

Closure of fisheries during spawning is not very effective as a conservation measure. To be effective, it is necessary to ensure that catches in the rest of the year in the other areas do not increase to make up for the loss of catches in the closed areas.

The total allowable catches and national quotas should be reduced. Harvesting juvenile fish is more damaging than spawning fish as more fish would be required to make up for the weight of catch.

Properly calculated total allowable catches (TACs) and quotas do not necessarily allow the fishing all year, restrictions on the fishery do not mean that the scientific assessment must be wrong.

TACs and quotas are an indirect method for controlling fishing effort: direct limitation is another way of achieving the same objective.

In summary, conservation entails the wise use of resources to make them available not only for now but also for future generations. Several measures, national and international regulations are available which may enable the effective work of conservation.

Read Also : How To Generate Money From Industrial Waste

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Benadine Nonye is an agricultural consultant and a writer with several years of professional experience in the agriculture industry. - National Diploma in Agricultural Technology - Bachelor's Degree in Agricultural Science - Master's Degree in Science Education - PhD Student in Agricultural Economics and Environmental Policy... Visit My Websites On: 1. Agric4Profits.com - Your Comprehensive Practical Agricultural Knowledge and Farmer’s Guide Website! 2. WealthinWastes.com - For Effective Environmental Management through Proper Waste Management and Recycling Practices! Join Me On: Twitter: @benadinenonye - Instagram: benadinenonye - LinkedIn: benadinenonye - YouTube: Agric4Profits TV - Pinterest: BenadineNonye4u - Facebook: BenadineNonye

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