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Overfishing of Southern Bluefin Tuna

University/College: University of Arkansas System
Date: November 14, 2017
Words: 3449
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Overfishing of Southern Bluefin Tuna

Overfeeding of the Southern Bluffing Tuna The Problem Figure 1 : An adult Southern Bluffing Tuna flesh. (Ethnomusicology) Figure 1 : An adult Southern Bluffing Tuna fish. (Tetanus-macaroni) Conservationists are working hard across the world to protect endangered species. One problem that biologists are facing is the declining wild population of the southern Bluffing tuna and the main reason for this problem Is the rapid overfeeding of the fish.

The Bluffing tuna figure 1) Is a fish that Is only found In the southern hemisphere and has become critically endangered in the last 60 years. This Is mainly as a result of the Bluffing tuna being overfilled in the southern hemisphere for commercial usage in the fish market. It has been fish so extensively in recent years that it is now the near the point of extinction. The Bluffing tuna is not fished for the commercial canned tuna market but for the sushi market as it has a different taste to other tuna species.

Japan Is the largest consumer of this species of tuna, consuming more than 80% of the world’s Bluffing tuna catch [1] therefore demand for It there Is very high. The southern Bluffing tuna has only one spawning site, in the ocean off the coast of Indonesia. There are various other types of tuna fish in the oceans, but none of the others are as threatened by overfeeding as the southern Bluffing is.

The constant improvements in fishing technology and equipment has allowed knowledge of the main migration routes of the tuna, and so very effective fishing, and In the last 60 years marine conservationists have seen the population of the southern Bluffing Tuna drop by 92% This significant decline In the worldwide stocks of this tuna has led to the International union for Conservation of Nature (CNN) placing the Bluffing tuna n the critically endangered list and Greenback also added the fish onto their seafood red list [3].

This means that they recognize the fish is being overfilled and the population is in a vulnerable state. Figure 2 : A diagram to show the method of purse seine fishing. Figure 2 : A diagram to show the method of purse seine fishing. One of the mall advantages fishing boats have acquired Is the usage of Purse Seine fishing methods. This Is where a net, that can be up to km long, Is deployed over an area of sea, as seen in figure 2. Once deployed, bait is thrown out to attract fish and other marine life towards the nets.

The nets are then drawn in, and the bottom of the nets tightened so no fish can escape, but because of the size and shape of these nets, they catch everything that was in that area of sea, this means that a tuna fishing boat can be catching sharks, turtles, rays and even dolphins all by accident. All this dead by catch then has to be thrown back to the sea, as the boats are not permitted to catch these animals. If the method works to its full potential then one haul of the net has the potential to catch an entire school of Bluffing tuna, thus destroying the population in that particular area.

Reducing the population of Bluffing tuna directly reduces the biodiversity of the oceans but also reduces the gene pool within the Bluffing species because the individuals with rarer alleles can be removed from the population. These alleles might have been advantageous If the environment and variation within the species, also means that the southern Bluffing tuna is under increased threat from diseases and environmental changes such as global warming. In the natural acceptance of the oceans, other species of marine organisms may also be dependent on the tuna for it to survive, whether its food for them or they gain retention from its presence.

As there is an extensive food chain in the seas, overfeeding tuna is likely to have an impact on other species in the ocean. The main solution : Quotas The main solution that scientists have been trying to implement, is the use of quotas and restrictions on the fishing of Southern Bluffing Tuna(SUB). These simply limit the amount of fish the fisherman can catch and take back to shore, as well as restricting the areas that can be fished. The quotas can either be given to a country or a single fishing boat.

Introducing more quotas, catch limits and regulations on the fishing of he southern Bluffing tuna can help its population to reproduce and recover in numbers. Reduced pressure from fishermen allows more fish to breed and this can help it to increase the gene pool of the species which then brings greater diversity. Figure 4 : showing the allocation of TACT in recent years. Published by the SCABS. Figure 3 : A graph to show the annual fishing catch of the SUB in thousand tones. It peaked in 1961 with a total value of Just over 81,000 tones.

Figure 3 : A graph to show the annual fishing catch of the SUB in thousand tones. It peaked in 1961 with a total value of Just over 81 ,OHO tones. The total allowable catch (TACT) is a figure that is produced every year by the Commission for the Conservation of Southern Bluffing Tuna (SCABS). Scientists, DRP John Anal is the head scientist at SCABS, and biologist meet and calculate a number of what they deem would be a sustainable and safe volume of fish that is allowed to be caught by the global fisheries each year, they do this by looking at the parental stock biomass and ages of fish.

It is the total number of tuna that fishing boats are allowed to catch and take to shore in a year. In figure 3, it s clear when the quotas were introduced in 1984 as the number started decreasing rapidly until in 1990 when they TACT has not changed much at all in 20 years. The maximum TACT increase/decrease per year is 3,000 tones, this means that the number will always stay between what the SCABS think to be a sustainable amount. In 2013 the TACT had increased 500 tones from the previous year to a total of 10,949 thousand tones.

Of this total, Australia has the highest effective catch limit, with their total allowance at 4,698 thousand tones, and Japan in second with around 25% allocated [4] as seen in figure 4. This figure is set to rise in coming years as the wild stock levels of the tuna have raised slightly due to the introduction of quotas and conservation efforts which have relieved the pressure off the population as they are not being so heavily fished anymore. SCABS The SCABS was originally a voluntary organization that included Australia, Japan and New Zealand who started to introduce quotas on their fishing of southern Bluffing tuna in 1985.

The members at the time set up the commission in the first place because they realized that the SUB was in need of conservation and care, so started to introduce catch limits immediately. The organization became formalized in 1994, Thailand Joined in 2008, meaning there were 6 members. And the Philippines, South Africa and the European Community Joined as co-operating Non-Members of the group in 2004 and 2006. [5] All of these countries are now trying to carry on with their commercial fishing but try and make it a sustainable future for the population of SUB.

The commission “Conducts and coordinates a scientific research program aimed at providing information to support the Commission’s management The commission also has multiple regulations that countries have to comply with, the catch documentation scheme’ is a programmer which tracks the trade of the SUB and makes sure all transactions are valid and from genuine sources. All imports and exports also have to come with the catch monitoring form and the right SCABS documents.

The VIM (vessel monitoring system) also has been introduced in the past 5 years; this means that all the ships belonging to the countries involved that fish SUB have to have on-board satellite-linked VIM. This means that ships can be tracked on all of their Journeys to make sure none of them are going in no-fishing areas and are not fishing in the tunas spawning areas near Indonesia and Java, see guru 5, which shows the spawning grounds and the Journey taken by the Juvenile southern Bluffing tuna. Figure 5 : showing the spawning grounds and Journey of young SUB. Figure 5 : showing the spawning grounds and Journey of young SUB. Toolkits are calcium carbonate balance organs found in the inner ear of bony fishes. They are continuously deposited through the lifestyle of a fish, so studies can determine age and growth information of the tuna fish. ” [7]. The SUB only become sexually active at the age of around arrears+, so they have to survive a long time in he ocean before they can reproduce themselves. So when many of the fish that are being caught are under this age, it means that it is stopping the population from growing as none of the new fish are living to be of a reproductive age where they can multiple and thrive without threat.

This is evident in figure 5, where it shows that the young SUB have to cross through some of the fishing hotshots for the Australian tuna farms, which means many of them will get caught on their Journey. “The global stock of southern Bluffing tuna is in a poor state, with the spawning stock biomass currently estimated to be at 3 to 8 per cent of its unfinished levels” [8],This shows Just how big the problem is that the young population are being caught, and so not enough are living to be of reproductive age.

If the same fish are reproducing repeatedly, with few young SUB growing to be of mature age, then it means the gene pool within the SUB species is not increasing. This can result in the diversity between each individual decreasing, as the same alleles and genes will be passing down to each new young giving no variation. The specific spawning grounds are banned from any form of gashing, as well as some surrounding area, however if any Juveniles swim out of the protected areas, then they are free for fishing boats to catch.

I believe this solution is appropriate to use, as quotas, rules and regulations are fairly easy to enforce upon countries and companies, whereas not all countries will agree to setting up tuna farms or banning certain methods of fishing. The reduction in numbers of SUB that is being fished, is essential for stocks to rise and the species diversity and gene pool are working and are affecting the amount that is commercially caught. This is having the sired result of relieving the pressure on the stocks that are left and giving them a change to grow, and the variation of the species to increase.

It is also clear that as the stock levels of SUB have increased, the TACT are planned to also increase slightly from the previous years, showing the scientists at SCABS believe that increasing stock levels will remain sustainable. Although some could argue that this solution only partially treats the problem, as the tuna are still being caught and taken out the ocean, but a total ban on SUB fishing would never be feasible. At this moment in time, autos seem to be the most effective plan used by scientists which are actually in place and working on getting the SUB back to ecologically safe stock levels.

Implications Economic There are various economic problems/implications facing this solution. One is that the government must be supplying the money to fund the quotas and other methods used by the commission, and some may feel that there are other ways to use this money that could be seen as more beneficial to the country. Another issue is that if less tuna is allowed to be caught then companies are going to need less fishermen to attach that tuna, forcing people out of work.

This would obviously result in financial hardship for the individuals so not as much money will be spent back into the economy by that consumer as they will have to be more careful about how they are spending. If the TACT keeps declining in some countries then it could encourage and cause a boost in illegal trade and catching of SUB. Countries like Japan where demand is so high yet TACT is low, there may be a black market set up where people are selling unreported catch to customers, who Just want their supply of SUB and don’t mind where it is sourced from.

However, there could be some economic gains from this solution as the supply of tuna will be limited, but the demand remains high, so the price paid for the catch is likely to go up. In January 2013, one fish sold in Japan for over El million[11] , showing the value of the bluffing tuna, and the continued demand for it particularly for the such’ market. Therefore there could be increased earnings for those that are still involved in the legal fishing of SIFT, and this will obviously have positive effects for that economy.

Social Social issues from this solution are that people could be losing their Jobs, Just from jack of workforce needed. This could cause issues within local fishing communities; if half of the workforce is unemployed then it will lower morale within the community and could force people to move elsewhere causing housing prices to fall. The impact of this on the families will be great to as it will cause them to have a lower standard of living and could cause problems like depression.

Conflict between countries could also be a problem, if one country has a much lower TACT than another, then it is going to be demanding more SUB than it can legally take and therefore could make unrecorded catch. But there is also conflict between the scientists at SCABS and the fishing industry who also are part of the organization, because some of the scientists whereas the fishermen Just want to exploit the stocks and make as much profit as they can so they want to see the quotas raised so they can fish more.

Other problems Another problem with the quotas is that some countries have managed to get around the system by Just not recording catch they have obtained, as it would take them over their TACT. In Japan where the demand is so high for SUB, they have been getting unrecorded catch and selling it on. In 2005 Japan caught 25% over their TACT which was 1500 tones more than their 6065 tone limit. This caused the SCABS to tighten their rules and as a punishment, they cut Japan’s next TACT by 1 500 tones for the next year. 9] So this does also show that SCABS are willing to punish countries if they do not abide to the quotas and regulations. Alternative solutions Tuna farming and the ‘Clean Seas’ project The use of tuna farms and holding pens is a fairly new method used in the SUB trade. It is where tuna are caught in the nets of a purse seine boat and are towed through the seas to off-shore holding pens, see figure 6. The tuna are held captive in huge nets and are fed up until they reach market value.

Although this is not increasing any population, it is having a beneficial impact on the environment as no by-catch is caught thus it is not decreasing the biodiversity of that area of sea. Figure 6 : Showing one of port Lincoln off-shore tuna farms. Figure 6 : Showing one of port Lincoln off-shore tuna farms. Clean Seas are a company in Port Lincoln, Australia where a project is being set up that is trying to help the sustainability of SUB by attempting to breed them in captivity. Scientists are employed by Clean Seas to set p on-shore hatcheries, they replicate the breeding conditions of the SUB in the waters around Java, Indonesia.

They use lighting over the tank to simulate night and day and they use saltwater straight from the ocean that is pumped into the tanks to regulate temperatures and replicate currents. The female tuna are injected by hand with hormones that stimulate the females to lay their eggs, and then the males in the tank fertilize them. They then remove the fertilized eggs to prevent cannibalism once the eggs had hatched. They get millions of fertilized eggs, but only 2% of their eggs ever survive to become Juvenile. 0] Projects like these are currently driven by the commercial trade, aiming to produce sellable fish once the captive bred tuna have grown. But if tuna can become captive bred on a global scale then it would significantly reduce the pressure on the dwindling wild stock levels of SUB, and give a chance for the population and diversity to grow as the tuna would be able to reproduce safely. However, this solution does face a few problems. It is very expensive as the tuna need to be fed other fish regularly to grow, and the stocks of these feeder fish such as mackerel and sardines are also falling.

So Clean Seas is trying to develop a wheat-based pellet food that can be produced commercially and fed to the tuna instead. [10] Another problem is that projects like these are not being done on a global scale, so it is only benefiting the local areas, economically and environmentally. It is not the wild population stocks that are increasing, only the captive population, however if this method was used to release captive bred tuna into the ocean, then this would be directly increasing the wild population. Cuts, is the way forward,” said Christopher Bridges, a leading scientist at clean seas [10].

Ban of purse seine fishing/use of alternative fishing methods http:// www. Environment. Gob. AU/coasts/fisheries/commonwealth/southern-bluffing-tuna/ pubs/sub-attachments-fishery-report. PDF The overfeeding problem faced by the SUB is a result of the methods of fishing used by most of the big fishing companies in and around Australia. The method that does most environmental damage as well as catching large volumes of tuna is the purse seine method. As seen in figure 7, it is becoming an increasing problem as it is now the main method of fishing the SUB.

The use of these nets makes it a lot easier for the ships to catch large volumes of SUB at a mime, but also the size and shape of the nets means that a range of marine organisms are caught rather than Just the desired Bluffing tuna, because the use of this fishing method is not selective towards one species. Also, the habitat where these methods are used, such as coral reefs, can be destroyed by the nets as they are trawled across the sea bed, thus damaging the fragile ecosystems of the marine who live there. Figure 7 : A graph to show the Catches of southern bluffing tuna from 1952 to 2010, by gear type.

Both of these problems lead to the biodiversity and the variation in the surrounding rear decreasing, as various different types of species are taken from the ocean due to the damaging effects of the purse seine fishing. Due to the problems that purse seine fishing creates, a ban on the use of these nets could be trialed to help not Just the southern Bluffing tuna but also the ecosystems and species that live around them as well. An alternative method of fishing that is more sustainable towards the population could also be introduced by organizations like SCABS .

Pole and line fishing is a method used by more developing countries that involves a rod and line, here the fish are Just caught straight out of the ocean, so there is no damage to any of the surrounding habitat or ecosystems and if anything else other than the targeted species was caught then it could be safely returned to the sea in a matter of seconds. Conclusion Looking at the current available solutions, it appears that quotas, rules and regulations are the most effective way to protect SUB in the near future.

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