h2. Introduction to the Current Problem Facing Fisheries
h3. Bycatch
Fishing vessels throw back into the ocean a large percentage of their haul because they are not big enough or are not in demand. Federal regulations mandate that bycatch be returned to the ocean as "unharmed as possible" which are suppose to keep fish from being overexploited but bycatch restrictions often not implemented or enforced. When they are, most fish thrown back eventually die (Turning A Blind Eye ¶ 1-3).
Though federal law requires it, fisheries managers sometimes do not monitor bycatch levels. "In order to manage our fisheries effectively, fisheries managers must account for the additional fish and other ocean wildlife killed as bycatch, so that healthy fish populations are not overfished, sensitive or depressed populations are not driven to levels below which they cannot recover, and marine ecosystems are not degraded" (Turning A Blind Eye ¶ 4).
High mortality rates for non target fish species can change the ecology of an area such as changing the food web relationships, altering predator-prey relationships, and destroying the environment. In the long term, bycatch can lead to overfishing, decreased productivity, and reduction in the amount of catch (Turning A Blind Eye ¶ 5)
Almost 1,000 marine mammals, many species of which are critically endangered, die every day due to being tangled in fishing equipment, mainly nets. It is estimated that there are 308,000 accidental marine mammal deaths anually in fisherman's catch (Verrengia ¶ 1). The study "suggests that accidental captures known as "bycatch" in the fishing industry, may be the biggest immediate threat to these animals' survival - even more than ship collisions and pollution" (Verrengia ¶ 4). The researchers do however caution that their methods were not very precise as mortality statistics in some regions were unavailable so they arrived at their numbers by multiplying numbers from the United States numbers (Verrengia ¶ 17).
"The IWC banned most whaling in the 1980s. Norway ignores the ban, while Japan takes nearly 700 whales a year under a controversial IWC research exemption. Some native cultures are allowed to conduct strictly limited hunts" (Verrengia ¶ 10). "Commercial fishing advocates point out that cetacean deaths decreased 40 percent in the United States in the last decade as new federal laws were enacted and equipment improved" (Verrengia ¶ 13). Some improvements such as underwater alarms were implemented with the aid of fishermen during the 1990s (Verrengia ¶ 14). Scientists say that nets wrapped around the bodies of these mammals are often quickly cut away by fishermen so that they will not be traced by their equipment (Verrengia ¶ 15).
h2. Introduction to Different Fishing Gear and Their Impacts
h4. Precatching Technology
h3. Mobile Gear
h4. Midwater Trawling
h4. Bottom Trawling
Trawling involves one or two fishing vessels towing a large net usually for two or three hours at three or four knots and is used to catch a range of species including orange roughy, hoki, ling, hake, and squid. Recreational fishers are not permitted to use trawl nets. (Starfish)
Dredging consists of fishing vessel towing a rigid steel-framed dredge along sea floor to gather scallops and oysters. (Starfish) Dredging is used for harvesting bivalve mollusks such as oysters, clams, scallops from the seabed using a metal framed basket with a bottom of connected iron rings or wire netting called the chain belly. The lower edge of the frame has a raking bar, with or without teeth, depending on targeted species. Catch is lifted out of the sea by the raking (or teeth) and passes back into the basket or bag. Dredges are generally attached to a towing bar operated from each side of a ship simultaneously. (Fishonline)
Beam Trawls are made more effective by attaching tickler chains (for sand or mud) or heavy chain matting (for rough, rocky ground) that drag along the sea floor in front of nets to disturb fish in the path of the trawl, causing them to rise from the seabed into the incoming net. The trawls range in size from 4 to 12 m (weighing 7.5 tons in air) beam length, depending on the size and power of the ship. (Fishonline)
Demersal Otter Trawls are large, usually cone shaped net which are towed across the seabed. Fish are herded between the boards into the mouth of the trawl where they swim until exhausted. They then drift back through the funnel into the cod-end where they are retained. (Fishonline)
\\
The use of new fish-trawling gear is doing incalculable damage to the seabed, destroying essential habitats for marine life. Every kind of seabed - silt, sand, clay, gravel, cobble, boulder, rock reef, work reef, mussel bed, seagrass flat, sponge bottom, or coral reef can be trawled. For fishing rough terrain or areas with coral heads, trawlers since the 1980s have used "rockhopper" nets with heavy wheels that roll over obstructions. This fishing gear displaces commercial hook and line and trap fishers who fished without degrading the habitat. (Safina)
Bottom trawls churn the upper few inches of the seabed, gouge the bottom, and dislodge rocks, shells, and other structures and the creatures that live there. Much of the world's seabed is encrusted with and honeycombed with structures built by living things. Trawls crush, kill, expose to enemies, and remove these sources of nourishment and hiding places. This makes life dangerous for young fish and lowers the quality of the habitat and its ability to produce abundant fish populations. (Safina)
Trawling commonly affects the top two inches if sediment which is the habitat of most of the animals that provide food and shelter for the fish, shrimp, and other animals that humans eat. In a Gulf of Maine site surveyed before and after rockhopper gear was used many changes were noted including that much of the mud surface was eliminated, extensive colonies of sponges and other surface growing organisms were removed, and rocks and boulders had been moved and overturned. (Safina)
The simplification of the habitat caused by trawling makes the young fish of commercially important species more vulnerable to natural predation. In lab studies of the effects of bottom type on fish predation, the presence of cobbles as opposed to open sand or gravel-pebble bottoms, extended the time it took for a predatory fish to capture a young cod and allowed more juvenile cod to escape predation. A single pass of a trawl kills 5 to 20 percent of the seafloor animals. Georges Bank is swept 3 to 4 times a year, parts of the North Sea are swept 7 times a year, and along Australia's Queenland coast, shrimp trawlers plow the bottom up to 8 times a year. (Safina)
Studies suggest that large increases in bottom fishing from the 1960s to early 1990s likely have reduced the productivity of seafloor habitats, exacerbating depletion from overfishing. At 3 New England sites, studies within and adjacent to areas closed to bottom trawls before and after initial impact found that trawls significantly reduce cover for juvenile fish and the bottom community. In NW Australia, the proportion of high value snappers, emperors, and grouper species that congregate around sponge and soft coral communities dropped from about 60% of the catch to 15%. Less valuable fish associated with sandy bottoms became more abundant thereafter. Studies off Nova Scotia indicate that the survival of juvenile cod is higher in more complex habitats which offer more protection from predators. In another study, the density of small shrimp was 13 per square meter outside trawl drag paths and 0 in scallop dredge's path. (Safina)
Trawling is not uniformly bad for all species or all bottom habitats. A few species do better in clear-cuts, some species do better in trawled than in undisturbed habitats. A flatfish called dab benefits from trawling because its predators and competitors are eliminated and trawl wakes provide them with food. However, most species are not helped by trawling. (Safina)
Communities that live in shallow sandy habitats subject to storms or natural traumas such as ice scouring tend to be resilient and resist physical disturbances. Deeper communities that do not often experience natural disturbances are more vulnerable and less equipped to recover quickly from trawling. Watling and Norse's global review of studies covering various habitats and depths found that many of these were done in relatively shallow waters which are generally more resilient than deeper areas. 0 showed general increases in species after bottom trawling, 1 showed that some species increased while others decreased, 4 indicated little significant change, 18 showed serious negative effects. Watling has said that is trawling stopped today, some areas would recover substantially within months but certain bottom communities would need as much as a century. (Safina)
The Grand Banks study showed trawls making furrows but also smoothing out the sandy bottom, lowering abundance of sea urchins, snow crabs, soft corals, and other epibenthic creatures. The effects were less than expected and overshadowed by natural variability. Recovery took less than a year and no long terms effects were observed. The 1997-1999 Western Bank of Nova Scotia study of gravelly seabed typical of trawling areas made some food organisms such as horse mussels and worms more available as prey items. Physical disruptions were less than on sandy bottom, but lasted longer because gravel bottom is less disturbed by storms. On all banks, trawls did less damage than expected. Harm increased with the size of the bottom organisms and sponges and corals were particularly vulnerable. (Does fish-trawling harm the seabed?)
\\
Research shows that the degree of damage depends on the nature of the seabed and its organisms, fishing effort, and other factors. Sandy bottoms are most resilient; hard bottoms with corals, sponges were least resilient. Detailed sea bed maps are essential to manage human activities in a scientifically sound manner and minimize environmental impacts so Don Gordon says. (Does fish-trawling harm the seabed?)
\\
*Sediment clouds*
Sediment clouds are generated by turbulence from trawl doors contribute to fish capture. The clouds also add to the total suspended load which can decrease light levels on the substrate and smother benthos once sediment settles. Glatsoff (1964) showed that as little as 1mm of silt settling could prevent spat settlement in _Ostrea virginica._ Stevens (1987) claimed that high turbidity levels inhibited settlement of _Pecten novaezelandiae_ veliger larvae, depresses growth rates of adults and caused inefficient metabolism of glycogen stores through enforced anaerobic respiration. (J. B. Jones)
Trawl gear can also bring about vertical redistribution of sediment layers. Mayer et al. (1991) showed that heavy chain dredges could mix organic material on the surface with layers below the surface. The organic material removed from the surface metazoan-microbial aerobic chain transfers to an anaerobic system. Churning up the soft bottom (if anoxic) can create anaerobic turbid conditions that are capable of killing scallop larvae. Sediment resuspended from clam dredges in a Maine estuary did not improve the food value of the suspended materials available to filter feeders and actually decreased the food value since filter feeders had to filter more material to obtain nutrients. (J. B. Jones)
*Destruction of Non-target Benthos*
_Cyprina islandica_ (a large, heavy-shelled bivalve) only formed a large part of the cod and flatfish diet in Kiel Bay after trawling began in the area. Arntz and Weber (1970) concluded that the fish fed on bivalves crushed by the otter boards Medcof & Caddy (1971) and Caddy (1973) confirmed that feeding occurred on exposed and damaged benthic animals in trawl tracks. Stevens (1990) found that trawling caused no observable injuries to crabs. Butcher et al. (1981) found that that scallop dredging in Jervis Bay (Australia) caused little or no damage to the environment. Creutzberg et al. (1987) found that an experimental beam trawl had no effect on the catches of epibenthic animals on a mud substrate but on sandy locations, the number of chains did correlate to the catch. Bull (1986) found that in Golden Bay (New Zealand), after 9 months, the survival of _Pecten novaezelandiae_ spat was better than 20% in an area closed to trawling whereas in an adjacent area open to trawling, the percentage was only 0.8%. (J. B. Jones)
*Indirect Effects*
McLoughlin et al. (1991) found that natural mortality and indirect fishing mortality rates on scallop beds was much higher on fished scallop beds than natural mortality on unfished beds. 4 to 5 times as many scallops were crushed or damaged as were caught or landed by the scallop gear. McLoughlin et al. saw that within 9 months of starting up a fishery in Bass Strait Australia, that the stock of scallops was almost entirely lost. They attributed it to a suspected bacterial infection resulting from decomposing scallops on the seabed. Saxton (1980) saw a decrease of juvenile fish when the bryozoan beds were removed in Tasman Bay, New Zealand. Sainsbury (1988) found a significant decrease in sponge frequency on the Australian north-west shelf between 1967-73 and 1979. The loss of sponges and alcyonians and gorgonians led to a change in the composition of the catch between those years. The fishes _Lethrinus_ and _Lutjanus_ which were associated with habitats containing large epibenthos and were much decreased. The fishes _Nemipterus_ and _Saurida_ which lived in open sand had greatly increased. A general decrease in diversity can be predicted as long0lived and slow-growing species are removed or killed by human activities. (J. B. Jones)
*Conclusion*
The removal of macrobenthos has variable effects. In shallow waters where damage is intermittent, recolonisation occurs quickly. Where macrobenthos is substantially removed and recovery is not permitted, the change is permanent (Ex - _Sabellaria_ beds of Wadden Sea and the bryozoan beds of Tasman Bay) (J. B. Jones)
h2. Nonmobile Gear
h3. Purse Seining
The purse seine is a vertically hanging net with floats on its surface line and lead weights on its bottom edge. Attached to the weighted line are rings strung together by a drawstring wire. Ships encircle entire schools with the outstretched purse seine, then they pull the drawstring wire tight to trap the fish inside (AFMA). The Marine Conservation Society summarizes purse seining as, "one of the most aggressive methods of fishing and aims to capture large, dense shoals of mobile fish . . ." (MCI). This method is extremely effective for catching both surface dwelling and mid-water fish, especially tuna, sardines, mackerel, jack mackerel, and herring (Kuznetsov). The Alaska Department of Fish and Game reports that, in the commercial fisheries of Southeast Alaska, purse seines are responsible for 70-90% of the tuna catch. This yield consists of mainly pink salmon, but it also includes sockeye, coho, chum, and chinook salmon. This Current regulations in Alaska allow purse seining only in specific districts (ADFG).
*New Technologies*
While fishing companies have practiced purse seining essentially unchanged for the past 100 years, slight innovations in technology have recently made the net even more efficient and, therefore, lucrative. One such example is the "autonomous distance-controlled hydroacoustic system" which, once attached to strategic points along the net and submersed, emanates a low-frequency pulse which frightens fish into the net. This invention consists of a management block onboard the ship as well as the underwater blocks, attached to the net, which emanate the frequencies (Kuznetsov).
One invention analogous to the hydroacoustic system, but used for trawling, is the "towed remote controlled pneumoacoustic system." This machine, which is dragged between ship and trawl, creates a strategically located acoustic field, imitating the acoustics generated by predatory whales. Seeking to avoid the predator, fish congregate in the trawl's catching zone. This method greatly increases the catch without the necessity of altering boats or nets (Kuznetsov).
*Pros*
From the fisherman's point of view, the most obvious advantage of purse seining is its capability to harvest massive quantities of a species at once. With respect to the geographical environment (i.e. ocean floor, plant life), the purse seine is nearly harmless because, when properly handled, it never touches the sea floor. It doesn't sit in one place for a length of time longer than the boat can set it out and pull it in, thereby hardly altering the long term habitat with its temporary presence. Yet another defense for purse seining is its longevity. Purse seining has been practiced to the same end, and with virtually the same means, for the past one hundred years. Its practice preserves a culture more than one hundred years old of seine net fishing, especially prominent in California and the Northeastern coast of the United States (Skogsberg).
\\
*Cons*
Two general problems with purse seining are caused by its large-scale capabilities. The first is simply ecosystem disruption. The instantaneous removal of entire schools of a certain species of fish from an area leaves a vacant hole in the food web. This leads, initially, to predator death by starvation and prey overpopulation because their numbers are suddenly unchecked by a predator. In the long run, if the affected species survive, they may adapt their eating/breeding habits to flourish in a new and altered ecosystem.
The second flaw of purse seining is the large quantities of bycatch routinely caught and killed along with market fish. Marine mammals are commonly trapped within the encircling net, and they perish without means to escape. Before regulations forbade it, seining for yellowfin tuna often consisted of setting nets around dolphins (predators of tuna) on purpose to catch the most fish. Congress's Marine Mammals Protection Act of 1972, however, almost entirely eliminated the practice by 1997 (MCI). Additional regulations were set up by the Earth Island Institute and the HJ Heinz corporation in their 1990 "Dolphin Safe" standards (IMMP). Since their introduction in 1990, these guidelines have been accepted by 90% of world canned tuna companies and have reduced dolphin mortality (as bycatch) by 98% (now about 2-3,00 dolphin deaths per year) (MCI).
*Reducing Bycatch: The Dolphin Safe Standard*
* * The Earth Island Institute writes:
"In order for tuna to be considered "Dolphin Safe", it must meet the following standards:
# No intentional chasing, netting or encirclement of dolphins during an entire tuna fishing trip;
# No use of drift gill nets to catch tuna;
# No accidental killing or serious injury to any dolphins during net sets;
# No mixing of dolphin-safe and dolphin-deadly tuna in individual boat wells (for accidental kill of dolphins), or in processing or storage facilities; and
# Each trip in the Eastern Tropical Pacific Ocean (ETP) by vessels 400 gross tons and above must have an independent observer on board attesting to the compliance with points (1) through (4) above." (IMMP)
\\
*Sources*
Alaska Department of Fish and Game: Division of Commercial Fisheries. "Commercial Purse Seine Fishery." 26 July 2005. 17 Oct. 2007 <[http://www.cf.adfg.state.ak.us/region1/finfish/salmon/netfisheries/ps_info.php]>.
Australian Fisheries Management Authority, Australian Government. "Seine." Canberra, Australia. 29 June 2005 <[http://www.afma.gov.au/information/students/methods/]>.
International Marine Mammal Project, Earth Island Institute. "International Dolphin Safe Monitoring Program." San Francisco, CA. <[http://www.earthisland.org/dolphinSafeTuna/]>.
Kuznetsov, Dr. J.A. "Innovational Projects." Intensification of Multispecies Fishery. Vladivostok, Russia. <imf.fish-net.ru/inpr.htm>.
Marine Conservation Society. "Fish Online: Fishing Methods." England, Wales, and Scotland, UK. <[http://www.fishonline.org/caught_at_sea/methods/]>.
Skogsberg, Tage. "Preliminary Investigation of the Purse Seine Industry of Southern California." Fish Bulletin No. 9. State of California Fish and Game Commission, State Fisheries Laboratory. California State Printing, 1925. University of California, 2007 <[http://content.cdlib.org/dynaxml/servlet/dynaXML?docId=kt15800140]>.
h3. Traps
Traps are one of the most environmentally friendly fishing methods. They are highly selective, since fishermen can release unwanted fish alive when the traps are hauled up. They also do little to no harm to the ocean floor or other oceanic surroundings, as they are nonmobile. However, there is a huge problem associated with traps - ghost fishing.
In 1995, the FAO deemed ghost fishing to be one of the most seriously negative impacts in the present capture fishery industry (Matsuoka). When traps are lost, from storms or human negligence or otherwise, the vast majority will continue to catch and trap fish or other ocean life for months, or even years. Ghost fishing in some commercial stocks is estimated to be equal to 5-30% of the annual catch levels (Laist). There are already some measures being taken to prevent ghost fishing: the FAO code of conduct states that States should try to minimize catch by lost or abandoned gear, and many countries including Sweden, Poland, New Zealand, and the United States all have gear retrieval programs (Brown).
Gear retrieval programs, however, are not the best way to prevent ghost fishing. A study by Brown and Macfayden indicates that while these programs save fishermen about $32,000 per fleet per year, the time and money spent in retrieving the gear exceeds $65,000. But if these programs are used along with measures that prevent gear loss in the first place, the cost will decrease significantly. Another possibility is to develop new technology that allows for easier and cheaper retrieval of lost nets and traps.
Another measure being taken is the requirement of escape mechanisms. <<INFO>>. If these requirements are made more strict and widespread, then ghost fishing should decrease dramatically.
Unfortunately, there is little data about the effectiveness of escape mechanisms, or even truly accurate data regarding the impacts of ghost fishing on fish populations; most of the numbers discussed above are mere approximations. This is another area in which we can improve
h3. Hook and Line
h2. Alternative Fishing Technologies
Future improvements on beam trawls include electrified ticklers, which are less damaging to the seabed which have been developed but used only experimentally. Square Mesh Panels fitted in the 'belly' or lower panel of the net can reduce the impact of beam trawling. (Fishonline)
\\
Future improvements on demersal otter trawls include increasing the selectivity of trawl fisheries by seperated trawls which exploit the behavioral differences between fish species. For example, cod and plaice segregated into lower compartment of net while haddock are taken in upper part. The mesh size of the two compartments can be altered according to the size of the adult fish being targeted. Selectivity can also be increased by insertion of square mesh panels because unlike traditional diamond shape meshes, they do not close when the net is towed. Discard of immature fish also reduced by increasing the basic mesh size when fishing. Sorting grids are compulsorily fitted in nets in some prawn and shrimp fisheries to reduce bycatch of unwanted or non-targeted species including small prawn and shrimp. (Fishonline)
Most fishing methods target fish for human consumption. Fisheries targeting species for reduction purposes (manufacture of fish oil, meal, etc.) are referred to as industrial fisheries. Fish meal and oil produced almost exclusively from small, pelagic species for which there is little or no demand for direct human consumption. Methods of capture are purse-seining and trawling with small mesh nets (16-32 mm). Industrial species in North Sea and North-East Atlantic include: sandeel, sprat, capelin, blue whiting, Norway pout, and horse mackerel. Fish oil used in products ranging from margarine to biscuits. Fish meal is used in manufacture of pelleted foodstuff for intensively farmed poultry, pigs, and not least, agriculture. The main Impacts of industrial fishing is the removal of large quantities of species from the base of the food chain. (Fishonline)
h2. Policy and Regulation Relating to Fishing Technology
Recommended actions that would simultaneously safeguard the fishing industry as well as the seabed would include no-take replenishment zones where fishing is prohibited which would create healthy habitats supplying adjacent areas with catchable fish where the benefits can be seen within a few years. In New England, fish populations are still low but are increasing in areas where the regional fishery management and National Marine Fisheries Service have temporarily closed to fishing. Fixed-gear-only zones where trawls and other mobile gear are banned in favor of stationary fishing gear such as traps or hooks and lines that don't destroy habitat. What gear is permitted should depend on the bottom composition. Mobile gear allowed on shallow sandy bottom relatively resistant to disturbance but be barred from harder, higher-relief, and deeper bottoms where trawler damage in much more serious. Incentives for development of fish gear should be put in place that do not degrade the habitat on which it is dependent. Fish and fisheries are hurt by perverse subsidies that encourage overfishing, overcapacity of fishing boats, and degradation of habitat and marine ecosystems. Intelligently designed financial incentives are needed to encourage new and more benign technology. (Safina)
h2. Citations
Verrengia, Joseph. "Nearly 1,000 whales drowning daily in fishing nets: study ." +European Cetacean Bycatch Campaign+. 15 June 2003. 13 Sep. 2007 <[http://www.eurocbc.org/bycatch_death_toll_may_exceed_1000_cetaceans_daily_15june2003page1156.html]>.
"Fishing Methods." +STARFISH Student and teacher Resource Science Fact Sheets+. New Zealand Ministry of Fisheries. 13 Sep. 2007 <[http://www.starfish.govt.nz/science/facts/fact-methods.htm]>.
"Fishing Methods." +FISHONLINE+. Marine Conservation Society. 13 Sep. 2007 <[http://www.fishonline.org/site/www/caught_at_sea/methods/]>.
Jones, J. B. . "Environmental impact of trawling on the seabed: a review." New Zealand +Journal of Marine and Freshwater Research+ 26 (1992): 59-67. 13 Sep. 2007 <[http://www.rsnz.org/publish/nzjmfr/1992/4.php]>.
Safina, Carl. "Scorched-Earth Fishing." +Issues Online in Science and Technology+ (1998): 22 pars. 27 Sep. 2007 <[http://issues.org/14.3/safina.htm]>.
"Turning A Blind Eye: A Marine Fish Conservation Network Report." 1 June 2006. U.S. Public Interest Research Groups . 27 Sep. 2007 <[http://www.uspirg.org/home/reports/report-archives/ocean-conservation/ocean-conservation/turning-a-blind-eye-a-marine-fish-conservation-network-report]>.
"Does fish-trawling harm the seabed? - finding out the facts." +Fisheries and Oceans+ Canada Science. Department of Fisheries and Oceans Canada. 27 Sep. 2007 <[http://www.dfo-mpo.gc.ca/science/Story/maritimes/trawling_e.htm]>.
\\
\\
h2. World Fish Production
{center:class=myclass}
| !http://www.earth-policy.org/Indicators/Fish/FishTotal.gif! | !http://www.earth-policy.org/Indicators/Fish/FishSplit.gif! |
| Figure-1 | Figure-2 |
\\ !http://www.earth-policy.org/Indicators/Fish/Fish_China_Anchov.gif!
Figure-3
\\
|| Year || Fish Caught (million tons) || Aquaculture (million tons) || Total (million tons) || Fishing to Aquaculture Ratio ||
| 1950 | 18.7 | .6 | 19.3 | 31.17 |
| 1960 | 33.8 | 1.7 | 35.5 | 19.88 |
| 1970 | 62.7 | 2.6 | 65.2 | 24.12 |
| 1980 | 67.2 | 4.7 | 71.9 | 14.3 |
| 1990 | 84.8 | 13.1 | 97.9 | 6.47 |
| 2000 | 95.5 | 35.5 | 131.0 | 2.69 |
| 2001 | 92.8 | 37.8 | 130.6 | 2.46 |
| 2002 | 93.0 | 40.0 | 133.0 | 2.33 |
| 2003 | 90.2 | 42.3 | 132.5 | 2.13 |
Table-1
\\
h3. Current
As you can see from figures 1 and 2, the overall amount of fish being put out to market all over the world is increasing every year. The amount of fish pulled from our oceans is beginning to level off while the amount of fish provided by aquaculture is increasing. The problem is that our oceans can't currently support the amount of fish that we are pulling from it. This means that the amount of fish being pulled from the ocean currently (wild catch) must decrease for the ecosystem to stabilize.
Currently, there is about 132.5 millions tons of fish being produced worldwide. Of that, 90.2 million tons are fish that are pulled from the oceans and 42.3 million tons of fish are the result of aquaculture. It is at a point now where almost one-third of the world's fish production is provided by aquaculture.
| !http://www.earth-policy.org/Indicators/Fish/FishPerCap.gif! | !http://www.earth-policy.org/Indicators/Fish/FishPerCapSplit.gif! |
| Figure-4 | Figure-5 |
Figure-4 shows that rate at which the demand for fish has been met has slowed over the last 30 years due to the increase in the worlds population. The amount of fish per person has gone up, but the amount of that provide for by wild catch has remained constant over the years. The amount of fish per person has been allowed to increase due to the increased supply of fish provided by aquaculture. Because the population is still increasing, the world's demand for fish is increasing. If the amount of fish pulled from the ocean remains constant, as it has over the last 20 or so years, the amount of fish per person will begin to drop if which will cause people to starve, economies to collapse, and our fish stocks to be depleted.
\\
| !http://cache.eb.com/eb/image?id=73561&rendTypeId=4! | !http://cache.eb.com/eb/image?id=77058&rendTypeId=4! |
| Figure-6 | Figure-7 |
China is a major fish producer but is also a major consumer. Over the last few years, China has been putting more stock into aquaculture which has caused the amount of fish they produce to increase overall and the amount of wild catch to level off. {center}
h1. Sources (in progress)
General Knowledge / Article Search Engine
* Wikipedia - [http://en.wikipedia.org/wiki/Fishing#Fishing_techniques]
* Encyclopedia Britannica - [http://search.eb.com/]
* Web of Knowledge - [http://portal.isiknowledge.com/portal.cgi/wos?Init=Yes&SID=2AN2mMFka9JegBPfAKb]
Articles
* World Fish Production - [http://www.earth-policy.org/Indicators/Fish/Fish_data.htm#fig1]
* Marine Fishery Production - [http://search.eb.com/eb/article-230490]
// |