Thursday, 8 October 2015

Over-fishing

  • What is Over-fishing?
Over-fishing can be defined as the practice of excessive fishing to a point in which the fish stock is exhausted. This is usually when the amount of fish being caught cannot be replenished by natural reproduction.

  • How does Over-fishing occur?
                         >Global demand
                          >Intensity of fishing activities:
                  -overcapacity
                  -unsustainable fishing

The increasing human population is a major factor which leads to over-fishing as food supply and the size of the population go hand in hand. As the population size grows, the demand for food will also increase. According to the Worldometer website, (“World Population,” accessed October 8, 2015, http://www.worldometers.info/world-population/) the world population is growing at a rate of 1.13% and the average population change is approximately 80 million per year. With these drastic changes in growth, focus will be placed on the most cost effective and reliable food supplies. Although fishing can support major sectors of the world’s economy, the improper practices used can result in only short term benefits. Many fishing companies own large vessels which stay out at sea for days to fish. In aggregate, these vessels will catch tons of fish before returning to port. This is known as overcapacity. They use unsustainable methods such as trawling (dragging a huge net through the water) which destroys marine life living in the seabed and also catches other sea animals.


  • What are the effects of Over-fishing?
               > Decrease in biodiversity
                              >Ecosystem instability
                              >Economic loss
                                         >Food security problems

The most significant effect of over fishing that should be considered is the impact that it has on the biodiversity of the aquatic environment. Biodiversity can be defined as the variety of organisms in an ecosystem and it can be categorized into genetic diversity, species diversity and ecosystem diversity. As the fish stock dwindles, both species and genetic diversity decreases. Biodiversity is very important as each species has its own role to play in an ecosystem. For example, sharks are the apex predators of an ecosystem. They help keep the ecosystem in balance by feeding on the most available fish species.  If the shark population decreased drastically, the population of other fish species would rise to a point where there will be problems for food and space. This single change in the shark population can cause a chain reaction in the ecosystem. Biodiversity is also linked to ecosystem stability which is the ability of an ecosystem to recover quickly after any sudden changes or disturbances. Therefore if many species of fish are continuously being depleted, it will be more difficult for other aquatic organisms to adapt to these changes. Fishing is also a major source of revenue for many countries throughout the world. With reducing fish stock, there will be major economic loss which can affect other sectors of the country. As for the social effect of over-fishing, these include a decline in food security as well as the increased unemployment of fishermen. This will therefore make it more difficult to sustain a livelihood for many people.








No comments:

Post a Comment