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The essay critically gives insight on the impact of human activities on world wide fisheries. This is done by closely examining the positive as well as the negative influences man has had on fisheries. In addition, possible measures executed to curb the negative influences are brought forth. The research question guiding the paper is has man made an impact on worldwide fisheries. It is undisputable that mankind have been dependent on the ecosystems and have derived a myriad of benefits from such interaction ranging from ecological, social, environmental, economical among others (Coleman et al. 2004).
However, while deriving such benefits man in the last fifty years despite the fact that they coexisted with the various ecosystem have had tremendous impact on their surrounding. Fisheries which is defined as the type of industry or sector that focuses on catching, processing and selling of fish, as well as other aquatic organisms is one such benefit man has derived from marine ecosystem because of its industrial and commercial significance (Schultz, 1999).
According to Sinclair & Valdimarsson, 2003 human activities which refer to things, actions and deed done by the human race or cause certain things to happen ranging from agriculture, mining, constructions, industrial activities, ranching, and deforestation, among others have led to positive and negative changes in the environment that impact on world's flora and fauna, fisheries not being an exception. It is worth noting that activities that impact on water quality are of great impact to fisheries together with other human activities such as the type of equipment used to fish. Globally, approximately 37.0% of human population live within a range of 100km from coastlines, with the continuous increase in their numbers, marine ecosystems and fisheries as an industry is at great danger. Three main reasons have been attributed to human impacts on the environment these are; improved technology, skyrocketing population and changing habits of consumption.
Man through technological innovation has created artificial fields where fish can be reared. With such capabilities, the whole industry of fisheries which has been growing tremendously and in need of raw materials has had some from such field. This has created employment throughout the world.
On the same note, agriculture (farming) which contributes to a greater percent of GDP of most countries in the world has had some positive implications to fisheries. It is worth noting that through farming, fertilizers are used, during run-off, such nutrient find their way into marine ecosystems. The resultant is nourishment of sea food available to aquatic animals which later translates to more numbers that satisfy the industry. Additionally, discharge of sewage can also contribute to eutrophication.
It is worth noting that while trying to better life man came to intrducing exotic species to marine ecosystems to replenish and diversify marine lives. Such introduction saw to it that there were a variety of marine live that could support fisheries.
Man in his quest to better his life has left the marine ecosystem which is the harbor of fisheries in dismay. Various species have gone extinct; tremendously reduce in number, generally human activities have had more negative impact to fisheries as compared to advantages (Coleman et al. 2004). Although eutrophication has been thought to be a positive impact, it is also a blessing in disguise as it create dead zone. When nutrients from the main land as results of agriculture get their way into water bodies, it leads to over growth of algae which in turn feeds on nutrients and takes more oxygen in the water. Oxygen deficiency brought about by this phenomenon has lead to death of several marine lives. Additionally, runoff take sediments plus other substances such as pesticides used in farming.
Pesticides particularly have been known to either cause death to marine life or lead to biological magnification.
Human developed ship to be used in seas and ocean for transport purposes. With the knowledge that this was designed to handle very heavy cargoes, there are instances where ships have destroyed such habitats as coral reefs. Additionally, waste products and garbage are usually thrown in the water bodies (Schultz, 1999). Plastic bags for instance choke and kill marine animals. On the same note there are cases where the consignment mostly made of petroleum, bauxite, manganese and other metals are in transit and find their way to the marine ecosystem. Such chemicals do negatively impact on marine life and eventually to the whole industry of fisheries.
For instance, oil spillage under shipment might increase the rate of mortality; contaminate fish as well as other foods, negatively impacting on reproduction systems, thermal regulation, destruction of marine organic substrate and oxygen deficiency.
Through science, it was thought fit to introduce exotic species of marine life to control other over populated species. Although it was a nice initiative, the long term effect of such innovation has proved to be detrimental to the industry. Exotic in most cases nourished well, bred quickly and colonized the habitat at the disadvantage of the indigenous species. This later led to extinction of the indigenous species making introduction of exotic species a self defeating initiative.
As suggested by Sinclair & Valdimarsson, 2003 more importantly, due to increase human population which has led to an increase in demand of marine products for food among others have translated to utilization of advance fishing methods. These methods include trawling, driftnets, long lines, purse seining, seine netting among others are well known to catch and kill untargeted species of marine life. Consequently, trawling in particular is deemedd to destroy benthos while dynamite destroys coral reefs. These coupled with overfishing has led to acute reduction of species numbers and in extreme end extinction translating to people losing jobs among other economic implications.
Urbanization has seen to it that the rate of pollution has increased, for instance the volume of sewage especially untreated one that find their way to marine ecosystem have led to death of fish and other species (Schultz, 1999). Industries have the potential of releasing heavy metals such as lead, mercury among others which leads to biological magnification as a result of accumulation of such metal in organisms up the trophic level. Additionally, anthropogenic activities such as deforestation, use of fossil fuel has seen to it that the amount of carbon-dioxide released to the environment has tremendously increased leading to marine acidification.
Recreation activities especially hunting of whales as well as seals in the 19th century was an activity that thrived drawing a number of people. The result was a sharp decline in wildlife population of these animals. Shockingly, in 1830, seal were at the verge of going extinct leaving the industry on its knees.
Recent measures to curb human impacts to worldwide fisheries
It is worth noting that after realization of the negative impacts of human activities on fisheries a number of steps have been taken in various levels from regional, national and international. Among the major steps include, delineating marine ecosystems and protecting them, education and public awareness, introduction and promotion of selective methods of fishing aimed at reducing by-catch of untargeted species, developing and promoting methods that have less physical impact on the ecosystems, (Schultz, 1999) partially closing an habitat till wild population are replenished, advocating the use of biodegradable materials, efforts have also been made to reverse a number of negative human implication through environmental clean up and rehabilitation. However, it is important to remember that strong political will, public awareness, effective management, the willingness of states as well as those who make decisions are of paramount importance in the quest of protecting fisheries globally (Sinclair & Valdimarsson, 2003).
From the review of human impacts on fisheries, it is evident that there are both positive and negative implications brought forth. However, the negative impact out-way the positive ones hence calling for measures to be taken in trying to curb the menace. Among the recent steps taken to counter the negative impacts include advocating the use of biodegradable materials, delineating marine ecosystem and protecting it, creating public awareness through education to mention but a few. Nonetheless, political will, effective management and corporation among the relevant stakeholder are key in successfully addressing the problem.