Marine Life Extinction Caused by Over Fishing Our planet consists of 75% life-giving, life-sustaining water. From lakes to oceans, man relies on the waters of this planet to provide nourishment for survival - from drinking water to food to eat. Over the centuries, we have made use of these natural resources, but recently our use has turned to abuse as more and more marine species face extinction due to our over-use of the ocean resources.

Like we are a part of the great food chain in the ecosystem of the planet, various marine animals and species are threatened by extinction and decrease in population due to over-fishing of certain predators and/or members of the food chain that these animals rely on for survival.

Different species of marine life face extinction for various reasons, but the majority are in declined numbers because of over-fishing. Not all animals and fish varieties are in this predicament due to the demand in the fishing industry, but are victims of the fishing industry.

For example, the grey nurse shark, one of the most docile of the shark family faces extinction within 10 years, if not 7 years, due in part to injuries on fishing hooks and death in nets. An estimated 100 million sharks were killed in 2002 (ABC, 2003) and the decline in numbers is also largely due to "an alarming increase in the lucrative fin trade" (ABC, 2003). In Australia, the fishing industry is being urged to have stricter quotas and "close off areas at certain times of the year" (ABC) to give the population a chance to improve.

The restaurant industry may take partial responsibility for certain species to be declining in correlation to over-fishing, but many notable restaurants and chains within the industry have, in recent months, boycotted certain fish (like the Chilean Bass) in lieu of other species that are not threatened by over-fishing.

In the case of the grey nurse shark, traditional Chinese recipes and medicinal remedies are to blame for the cruel fishing habits against sharks. In many cases, sharks are fished for their fins only and left to drown once the fin has been removed. An increase in public awareness, inciting a boycott on shark fin foods could aid the dwindling shark population.

Other issues of over-fishing include the case of 'bycatch' which are the species caught in nets by accident. These marine animals include sea turtles, sharks, and dolphins that are badly injured or end up drowning in the nets. "If fisheries managers consider only the abundance of targeted fishes, he says, they'll "lose the sensitive species in the long run." And that could lead to ecological changes that end up affecting the targeted species" (Harder, 2003).

Whaling is another area of the fishing industry that has had dire consequences on other marine animals that otherwise wouldn't be subjected to primary fishing issues. In the case of Orcas, or Killer Whales, animals like sea otters, sea lions and fur seals have seen a decline in populations largely in part as "these creatures [have] become choice entrees for killer whales after industrial whaling wiped out the great whales that killer whales had been eating" (Ramsayer, 2003).

An analysis of data gathered correlating to seal populations in relation to over-fishing of whales off the Gulf of Alaska shows that from the 1960s to today there has been a steady decline in harbor seals (in the 1960s) then fur seals and stellar seals (in the 1970s) and more recently, sea otters. This data points to the Orca's eating habits and their necessity to find other food resources after the over-fishing of certain cetacean species like the sei, fin and sperm whales (Ramsayer).

Further analysis into the practices of the fishing industry and the course this plays in fish populations show that beyond revealing the numeric of what the seas have lost through over-fishing, "recent studies hint at the enduring economic costs of mismanaging marine resources. Unless governments take immediate, dramatic steps to curtail over-fishing and undo the damage that's been...

Research has shown that fish populations do better in retaining growth in their population when they are not under the conditions of over-fishing and fishing practices within any given region.
This is to say that any fish population subjected to non-industrial fishing practices, are able to sustain their population density to about half its natural size, which is the optimal level for a fish community. At smaller densities, fish population reproduces at a much slower rate, which when faced with industrial-fishing can cause a no-win situation for fish populations. "Archived fishing records indicate that most fish stocks now lie well below the size that would produce maximum sustainable yield" (Harder).

There is a no-win situation for fish populations that are decreasing as fisheries insist on over-fishing these numbers dwindle so low that commercial fishermen turn to other species of fish to exploit. "The discovery of more abundant fish stocks in less exploited waters masked for decades the falling yields of populations and species" (Harder). Eventually, this vicious circle leads to declines in areas of the ecosystem that are directly affected by over-fishing, as in the case of the Orca, and other marine life, such as coral reefs.

One notable case in regards to coral reefs, are the reefs in the Caribbean that have been affected by the rapid decline in Diadema antillarum (sea urchins) who are responsible for keeping coral reefs clean. Their numbers were affected by an unknown germ that plagued reefs in 1983, but "several biologists have speculated that this urchin's dominance reflected an over-fishing not only of other reef grazers -- predominantly parrot fish and surgeon fish -- but also of Diadema's many predators, which included toad fish and queen triggerfish" (Raloff, 2001). Even though this species of sea urchin is showing an increase in numbers, the initial over-population of them were due in part to over-fishing in the area.

This particular case is almost a paradox of sorts because over-fishing allowed for the population to increase, thus aid in keeping the corals clean. Once their numbers had dropped, it would be easy to think that the over-fishing of their predators would allow for a steady incline of their population, still this hasn't happened because populations are widely spread apart, and their natural resource for food has declined due to over-fishing of members of the coral ecosystem.

This particular issue is demonstrative of modern fishing practices. Along with causing the decline in fish populations, modern fishing techniques have also been altering the seas' ecosystems. Skimming large and medium-size fish off the top of oceanic food webs has left a disproportionate fraction of marine biomass at the lower end of the "pyramid of life" (Harder). Beyond skimming, bycatch species are also casualties of modern fishing practices, as we have already discussed.

In order for over-fishing issues to be tackled, it is important that the public are made aware of the long-term affects certain fishing practices have on the ocean environment. Overfishing at sea, development along coasts, and increasing pollution from cities and fields are leading to the decline of ocean wildlife and the collapse of ocean ecosystems (Environment, 2003). Ocean areas and coastal populations of fish and marine life need to be preserved and protected so that other species within the ecosystem are given the chance to regain in numbers, if this doesn't happen, than eventually populations of other marine life will face extinction.

Of the ways to encourage public awareness, the fact that 60% of the world's oceans fall under the category of international waters will aid in the formation of a global public trust that will not only promote awareness of fishing issues, but ensure that no one nation or country's practices can dominate over fishing practices. "A major study in Nature last month reported that…