Fisheries

Fisheries are involved in raising or harvesting fish. Fisheries can be farmed or wild, saltwater or freshwater. They are categorized as small-scale, recreational, and industrial-scale. There are certain species fisheries all over the world for molluscs, echinoderms, and more.

Almost 80 percent of the world’s fishery catches are attained from seas and oceans, as opposed to inland waters. These marine catches have continued to stay relatively constant since the mid-nineties. Most marine fisheries are based near the shore. This is because harvesting fish is much more abundant near the coastal shelf, due to the excess of nutrients available from coastal land runoff and upwelling.

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Overfishing 

Overfishing is the removal of too many fishes at once, due to which the breeding population becomes too little to recover. Overfishing often goes hand in hand with extreme kinds of commercial fishing that draws in vast quantities of unwanted fishes or other animals, which are later discarded.

Overfishing is one of the reasons for the decline of fishes and unemployment in several different countries. In simple terms, overfishing can be defined as overexploitation where fish stocks are basically reduced below the acceptable level. Poor fishing management is the chief cause of overfishing. Critical reduction transpires when the level of exhaustion is so high, that the fish population will be no longer able to defend itself. It mainly happens when there is a drop in fish population size and may eventually result in fishery breakdown or even local extinction.

There are three types of biological overfishing: ecosystem overfishing, growth overfishing, and recruit overfishing. 

1. Ecosystem Overfishing: Ecosystem overfishing transpires when the stability of the ecosystem is changed by overfishing. With dissolutions in the profusion of large predatory species, the excess of small forage types grows, creating a change in the balance of the ecosystem towards smaller fish species. 

2. Growth overfishing: Fish harvested at an average size which is smaller than the maximum yield per recruit can produce, is known as Growth overfishing. 

3. Recruit overfishing: Recruit overfishing happens when the spawning biomass (mature adult population) is exhausted to a level where the reproductive capacity replenishes itself. Expanding the spawning stock to an end level is the strategy taken by supervisors to rebuild an overfished population to a sustainable level.

Types of Fisheries 

Fisheries are done for both commercial or subsistence. In India, there are mainly four types of Fisheries. 

• Inland or freshwater Fisheries

• Marine Fisheries 

• Pearl Fisheries

• Estuarine Fisheries

Inland Fisheries: The fishery aspects of waters are dealt with in Inland fishery. India is one of the wealthiest inland fishery resources in the world. The inland fisheries consist of two types of water, namely, the brackish and the fresh. The lagoons and mangrove swamps constitute the saline water. In pisciculture, which usually is concerned with the small water bodies, the eggs of the fish has to be seeded, nursed, tended, raised, and eventually harvested when grown to the table size.

Marine Fisheries: Marine fishery deals with the fishery aspects of the seawater or ocean. Marine fisheries of the nation have recorded a constant increase in the post-independence period, and today it offers about 46% of the total haul of the country. 

Pearl Fisheries: Pearl Fisheries are usually on the ridges or rocks or dead coral areas forming large pearl banks at a depth of 18-22m. Pearls of the high-value site are obtained from pearl-oysters. The Gulf of Mannar, Gulf of Kachchh and Palk Bay, and Andaman and the Nicobar Islands are the Principal centers. 

Estuarine Fisheries:  Estuarine fisheries are restricted to the estuaries, lagoons, backwaters, tidal estuaries, the saline water lakes of Pulicat, and Chilka, and the backwaters of Kerala. Prawn is a substantial variety.

Resource Depletion 

Resource depletion is the loss of resources at a faster rate than it can be replaced. The utility of a resource is a direct result of its availability in the value of obtaining the resources and its nature. The more a resource is exhausted, the value of the resources increases. There are various kinds of resource depletion such as mining for minerals and fossil fuels, deforestation, aquifer depletion, contamination of sources, slash-and-burn agricultural practices, Soil erosion, and overconsumption, excessive or unnecessary use of resources.