Fisheries are harvested based on their value. They can be wild or farmed, freshwater or saltwater. For example the tuna fishery of the Eastern Pacific. Capture fisheries can be categorized as small-scale, industrial scale and recreational. There are certain species fisheries all over the world for echinoderms, mollusks and more.
The science of harvesting or producing fish and other aquatic resources for the purpose of providing human and for purpose of obtaining fish products namely oil, recreational sports, obtaining ornamental fish and more. Typically a unit is defined by some authority to be a fishery. Basically, fishery defined based on the type of fish, a number of people involved, class of boats, method of fishing, seabed and the purpose of activities.
A fishery may involve the process of raising fish through fish farming or capturing of wild fish. More than five hundred million depends upon fishery directly or indirectly for livelihood. Overfishing as becoming one of the reasons for a decline in fish stocks and employment in several developing countries. In simple overfishing can be defined as an overexploitation where fish stocks are basically reduced below the acceptable level.
Overfishing can occur in various water bodies of different sizes such as river, ponds, lakes and even oceans and it may end up with resource depletion, low biomass level and reduction in biological growth rates. Sustained overfishing may sometimes lead to critical depletion. For instances, overfishing of sharks had resulted in damaging entire marine systems.
Critical depletion occurs when a level of depletion is very high enough that the population will be no longer able to sustain itself. It mainly occurs when there is a decline in population size. This may ultimately result in fishery collapse or even local extinction.
Resource depletion refers to consumption of resources rather faster than it can be expected. We all know natural resources are divided into renewable and non-renewable resources. Suppose if the usage of resources beyond that of replacement is termed as resource depletion. It is a common term that is used regarding farming, mining, consumption of fossil fuels and usage of water.
There are several reasons for resource depletion and some include deforestation. Soil erosion, mining of minerals and fossil fuels, overpopulation, slash and burn agriculture practices, aquifer depletion, contamination of resources and much more.
Types of Fisheries
Fisheries are done either for subsistence or commercial. Most of the world’s fisheries account from oceans or seas nearly ninety percent. the marine catches have relatively stayed constant. Most of the marine fisheries are carried out at the coast. The main reason for this is it is relatively easier in shallow waters than in open sea.