"We depend on the oceans---for food, jobs, recreation and solace. Ocean currents circulate the energy and water that regulate the earth's climate and weather and thus affect many aspects of the human experience, whether we live on the nation's coasts or its heartland" (Pew).
Climate Change
Over the past century or so, the earth has seen a significant rise in average global temperatures. Studies show that average surface temperatures have been rising at a rate of approximately 0.1°C/decade, which is significant when compared to estimates of historical values (IPCC, 2001). Whether this is primarily a result of anthropogenic influences such as emission of greenhouse gases, or of natural repeating fluctuations in climate, global warming will have a profound effect upon the oceans and should therefore be of great concern to anyone in charge of global fisheries. It is also very likely that global warming will accelerate in the near future due to positive feedback mechanisms (IPCC, 2001). Climate change is somewhat difficult to monitor, and even more so to predict accurately. Despite this, research on current systems as well as research into past global warming events provides us with an idea of what might be expected in future years. By knowing the general trends of climate change, an understanding effect on fisheries can be extrapolated.
Annual anomalies of global average land-surface air temperature
The melting of glacial ice and the thermal expansion of ocean water will cause sea levels to rise in future years. While this is unlikely to have a great effect on most ocean life, there are some cases where the change might be too fast for certain ecosystems to adapt. This could be a particular problem with coral reefs, which might not be able to grow fast enough to counteract the rise in sea level (Harley, 2006).
The change in temperature will cause changes in water chemistry, which in turn may have drastic effects on certain species, especially those with low tolerances. Many life processes in animals and plants are dependent on temperature, and could be significantly altered by a rise of even a few degrees in temperature (Harley, 2006). Higher temperature waters, such as those in the tropics have less primary production in the form of phytoplankton, which almost all fish derive their energy from. Addition of fresh water from melting ice caps decreases the salinity of ocean regions, which can be detrimental to species with low tolerances to changes in salinity (Harley, 2006).
As seawater warms, it also loses its ability to dissolve certain gases. One of these is O2, which is essential to all animals for respiration (Harley, 2006). Geological records of past global warming events show evidence of severe periods of anoxia on large to global scales (Bralower, 2002). A significant drop in the levels of O2 would result in result in a decrease of metabolism of animal life. CO2, however, is not near its saturation levels in the ocean. As CO2 levels rise, it will be taken in by the ocean where it reacts to form Carbonic acid, thus lowering the pH of the water (Harley, 2006). Acidic conditions could have detrimental effects on sea life, especially those that depend on significant amount of CaC03, such as shellfish.
The introduction of fresh water from melting ice caps can also affect deep-water thermo-haline currents. Because it lowers the density of water in polar region, it can prevent the sinking of water here, thus weakening or stopping the overturn of the ocean. A current location where some models predict such an event occurring is in the north Atlantic with the shutdown of the Ocean conveyor (Gagosian, 2007). Historically this has resulted in severe cases that cause a build up of toxins in the ocean, which is linked to mass-extinction events (Bralower, 2002). It is also possible that a similar event could prevent the transport of water from the tropics to the poles, causing a period of rapid climate change.
The warming of the atmosphere is expected to result in intensified atmospheric pressure gradients. There is already some evidence that this has resulted in increasing storm frequency and intensity in recent years. Atmospheric conditions are largely responsible for surface currents, which transport water in the surface layers of the ocean where most of the biomass resides (Harley, 2006). Modeling predicts that advection and upwelling will increase as a result of global warming, especially in the eastern boundary currents. Increased advection is generally linked to decreased biomass. Upwelling can often increase the biomass as it provides a source of cold, nutrient-rich water to the surface, but a strong upwelling current can also be disruptive. It is also suggested that global warming could increase thermal stratification, which would decrease upwelling (Harley, 2006).
Changes in conditions of water due to climate change will likely change the distribution of many species. For instance as temperature rises, many species will begin shift towards higher latitudes in order to remain under similar environmental conditions (Harley, 2006). This shifting of species allows for the introduction of alien species to ecosystems where they were not previously present, thus having the potential to greatly change the ecosystem. For instance, huge swarms of mauve stingers (Pelagia nocticula), which can devastate populations of fish, are becoming common in the waters off of Britain, a location where they were rarely spotted decades ago (CNN, 2007).
Another adverse effect from global warming is coral bleaching. The impact of coral bleaching is most obvious in fish, which feed specifically on corals, as do most butterfly fishes. The fish were gradually starving to death and the decline in numbers indicated they had also failed to breed in the months and years following the destruction of their reef. Coral bleaching is caused by high water temperatures that cause the corals to shed their symbiotic bacteria and die. More than 30% of coral reefs throughout the world are already severely degraded and corals on 60% may be lost by 2030 due significantly to bleaching as the climate warms (ARC, 2007).
It is also likely that climate change will have effects on the human aspects of many fisheries. Sea level rise may threaten many coastal areas. Thermal expansion of seawater is expected to cause a rise of 0.09 to 0.37 m over the next century (IPCC, 2001). This may threaten coastal cities, and infrastructure of the fishing industry in some areas. It is also predicted that storms such as monsoons and hurricane my increase in number and intensity as a result of global warming (IPCC, 2001). Flooding and storm surges could also result in damages to fishing infrastructure in locations prone to these disasters. Terrestrial effects of global warming could effect agriculture in certain areas by the changes in timing and intensity of droughts and flooding, as well as the effect of increased CO2 on the growth of crops and weeds. There are also likely to be effects on agriculture by sustained changes in temperature and precipitation, such as the desertification of the southwestern United States (IPCC, 2001). This could lead to a change in the demand for fish by some regions.
There is a large amount of uncertainty in the future of climate change. Although predictions can be made about what will happen, no one is sure exactly how global warming will effect the oceans and fish populations. However, the climate is an important factor in the formulation of a plan for fishery management. The climate will not change uniformly over the entire globe. For instance, climate the effects of global warming are likely to be more pronounced in the polar latitudes. Thus our predictions must be formulated specifically for different regions. Due to the importance of climate change to fisheries, we propose that we should set up a system for analyzing data as global warming progresses. Information such as temperature, salinity, pH, gas solubility, biomass, species population, and current strength and direction in order to look for trends that would allow us to better predict the future climate of various regions. Also, more work has to be done, determining quantitatively how fish populations react to climate change. As these quantities are monitored, we should begin to see trends in the progression of climate change.
Once trends have been determined the plan for fishery conservation would then be modified in order to counteract whatever effects were being caused by the climate change. For instance, with many of the predicted changes, the ecosystem could be able to support a smaller population of fish than it does currently. As soon as this realization comes about, restrictions must be changed to fit the reality of the situation. These changes could be made to a number of different restrictions such as technological restrictions, taxes, or closed areas, but we propose it would be most beneficial to have as direct an effect as possible on the fish populations. For this reason we propose using quotas as our main form of restriction. This would allow for the most accurate control over the number of fish we are taking out of the environment, and allow the restrictions to be changed more easily when a new trend in climate change is found. The most important aspect of the plan with respect to climate change is that it has to modifiable, so that we can be constantly improving our approach as we improve our understanding of climate changes effects. If we are to this approach is most likely valid for other aspects of this problem as well. This approach, however, would require a great improvement in our understanding of fish population dynamics. Therefore, it would be prudent to apply other restrictions until this point is reaches.
One possible method of reacting to a specific negative effect of climate change - decreasing natural phytoplankton levels and debasing the ocean food chain - is "ocean fertilization" with Iron. This allows high levels of phytoplankton growth in areas deficient in this nutrient (Jones & Young, 1997). Due to the unknown negative effects of this technique in large amounts (Chisholm, Falkowsi, & Cullen, 2002), we do not advise this method only in very specific, controlled cases to determine its benefits and effects.
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We acknowledge that addressing the issue of global climate change is outside the scope of Mission 2011's proposed solutions. However, this is a matter of such global importance and potential impact that to not discuss the issue at all, even briefly, would have been negligent. Furthermore, we emphasize that slowing or stopping the progress of anthropogenic global warming is necessary. There are many other groups currently working on this issue. For more information on this topic we suggest visiting the website of the Intergovernmental Panel on Climate Change at <http://www.ipcc.ch>. However, we have proposed some ways in which solutions should be modified in order to address the effects of climate change.
The Effects of Global Warming
Figure 1. Projected surface temperature changes by 2099. ("Climate Change 2001: The Scientific Basis," 2001)
Over the past century or so, the earth has seen a significant rise in average global temperatures (see Figure 2). Studies show that average surface temperatures have risen at the rate of approximately 0.1°C/decade, which is significant when compared to estimates of historical values (IPCC, 2001). Regardless of whether this temperature increase is primarily a result anthropogenic causes, such as as emission of greenhouse gases, or natural fluctuations, global warming will have a profound effect upon the oceans and should therefore be of great concern to anyone in charge of managing global fisheries. It is also very likely that global warming will accelerate in the near future due to positive feedback mechanisms, including the lowering of the Earth's albedo due to melting of polar caps (IPCC, 2001). Climate change is quite difficult to monitor, and even more difficult to predict accurately Despite this, research on current systems, as well as research into past global warming events provides a general idea of what can be expected in future years. Knowledge of these general trends will allow us to better understand the effects and, consequently, better manage fisheries.
Figure 2. Annual anomalies of global average land-surface air temperature (Jones et al., 2001).
The melting of glacial ice and the thermal expansion of ocean water will cause sea levels to rise in future years. While this is unlikely to have a great effect on most ocean life, there are some cases where the change might be too fast for certain ecosystems to adapt. This could be a particular problem with coral reefs, which might not be able to grow fast enough to counteract the rise in sea level (Harley, 2006). The loss of these ice sheets is also expected to contribute to global warming, as it would lower the albedo of the earth, causing less solar radiation to be reflected back out into space (IPCC, 2001).
In the next century, models predict average water temperatures will increase by 1 to 7 degrees Celsius (IPCC, 2001). Many life processes of marine animals and plants are dependent on water temperature, and could be significantly altered by a rise of even a few degrees in temperature (Harley, 2006). Higher temperature waters, such as those in the tropics, have less primary production in the form of phytoplankton. This is mainly due to the fact that a greater temperature gradient causes more intense stratification of the water, thus weakening the upwelling of cool, nutrient-rich water to the surface. A decrease in primary production causes a decrease in the numbers of individuals at higher trophic levels, including fish that depend on phytoplankton for food (Harley, 2006). Therefore, in many cases, it is reasonable to believe that warming of seawater will cause fish stocks to decrease (Harley, 2006).
Changes in the temperature of ocean water have the potential to cause significant changes in water chemistry. Addition of fresh water from melting ice caps decreases the salinity of ocean regions, which can be detrimental to species with low tolerances to changes in salinity (Harley, 2006). Also, as seawater warms, its ability to dissolve gases decreases dramatically. One of these gases is oxygen, which is essential to all animals for respiration (Harley, 2006). Geological records from past global warming events has shown evidence of severe, large-scale hypoxic episodes, sometimes reaching global scales (Bralower, 2002). A significant drop in dissolved oxygen levels would have a detrimental effect on many species. Another critical area of seawater chemistry that will likely be affected by global warming is the carbonate buffering system. The ocean have an enormous capacity to take up carbon dioxide. However, as atmospheric carbon dioxide levels rise, the equilibrium of the carbonate-bicarbonate-carbonic acid cycle will shift towards greater amounts of carbonic acid, lowering the pH of the water (Harley, 2006). Like temperature, there are many species who are sensitive to even small changes in pH. Ocean acidification would have detrimental effects on sea life, especially important calcareous primary producers, such as coccolithophores, and animals that posses carbonate shells. There is also geological data which indicates build up of toxins in the ocean during intense global warming events (Bralower, 2002).
The introduction of fresh water into the oceans from melting ice caps can also affect thermohaline circulation. Since fresh water is less dense than salt water, it floats on the surface in high latitude regions. This cap prevents the sinking of water in regions of downwelling, thus weakening or stopping the overturn of the ocean. Current models predict that a shutdown of downwelling in the North Atlantic could occur soon and lead to a shutdown of global ocean circulation (Gagosian 2007). A shutdown of global thermohaline circulation is likely to cause rapid and severe changes in climate, with similar changes in temperature to what has been recorded over the past century occurring on the scale of decades (Gagosian 2007).
Warming of the atmosphere is expected to result in intensified atmospheric pressure gradients. There is already evidence that this effect has increased the frequency and intensity of storms over recent years. Atmospheric conditions are largely responsible for surface currents, which transport water in the surface layers of the ocean where most of the biomass resides (Harley 2006). Modeling predicts that advection, the lateral movement of water, will increase as a result of global warming, especially in the oceans' eastern boundary currents. Increased advection is generally linked to decreased biomass (Harley 2006). In some cases global warming has been linked to increases in the intensity of upwelling, as it has along the coast of California (Harley, 2006). Upwelling can often increase the biomass as it provides a source of cold, nutrient-rich water to the surface, but a strong upwelling current can also be disruptive. It is also suggested that global warming could increase thermal stratification, which would decrease upwelling (Harley, 2006).
Climate change will likely change the geographical distribution of many species. For instance as temperature rises, many species will have to shift to higher latitudes in order to remain under similar environmental conditions (Harley, 2006). These species shifts can introduce alien species to ecosystems where they had not been previously present, which can fundamentally alter these ecosystems. For instance, huge swarms of mauve stingers (Pelagia nocticula), which can devastate populations of fish, are becoming common in the waters off of Britain, where they had not been known until recent years (CNN, 2007). There are, of course, other variables that determine species distribution, and thus the shifts will not be this simple. For some species, such as the Antarctic Icefish, there may be no higher latitudes to which they can move. For these species, climate change may well lead to extinction (Pauly 2007).
Another of the more visible effects of climate change is coral bleaching. When hermatypic corals are stressed by high water temperatures or other stimuli, they expel their symbiotic zooxanthellae from their tissues. This process deprives corals of the color, as well as of their primary source of nutrition. If corals are without their symbionts for too long they can perish from starvation. The impact of coral death then spreads through the reef ecosystem. Secondary effects are most obvious in fish, especially among those that feed specifically on corals, such as butterfly fish. Studies have indicated that such fish were gradually starving to death and that their decline in numbers resulted from a failure to breed in the months and years following the destruction of their reef. As it stands today, more than 30% of coral reefs throughout the world are already severely degraded and up to 60% of corals may be lost by 2030 due to temperature induced bleaching (ARC, 2007).
It is also likely that climate change will have effects on the human aspects of many fisheries. Sea level rise may threaten many coastal areas. Thermal expansion of seawater is expected to cause a rise of 0.09 to 0.37 m over the next century (IPCC, 2001). This may threaten coastal cities, and infrastructure of the fishing industry in some areas. It is also predicted that storms such as monsoons and hurricanes may increase in number and intensity as a result of global warming (IPCC, 2001). Flooding and storm surges could also result in damages to fishing infrastructure in locations prone to these disasters. Terrestrial effects of global warming could effect agriculture in certain areas by the changes in timing and intensity of droughts and flooding, as well as the effect of increased carbon dioxide on the growth rates of crops and weeds. There are also likely to be effects on agriculture by sustained changes in temperature and precipitation, such as the desertification of the southwestern United States (IPCC, 2001). A decrease in agricultural yield could increase the demand for fish.
Recommendations:
One possible method of reacting to a specific negative effect of climate change - decreasing natural phytoplankton levels and debasing the ocean food chain - is "ocean fertilization" with finely powdered iron. This allows high levels of phytoplankton growth in areas deficient in this nutrient (Jones & Young, 1997). There are significant technical problems related to this approach. Also, the large-scale effectiveness of iron fertilization is extremely speculative (Chisholm, Falkowsi, & Cullen, 2002). Hence, we do not advise this method until significantly more research has been conducted.
Figure 3. Range of future temperature predictions made by different models (IPCC, 2001)
There is a large amount of uncertainty in the future of climate change. Figure 3 shows the variation between the predictions of the average global temperature by different models. Although predictions can be made about what will happen, there is no way to know for certain how global warming will effect the oceans and fish populations. However, the climate is an important factor in the formulation of a plan for fishery management. It is important to be aware that climate will not change uniformly over the entire globe. For instance, the effects of global warming are likely to be more pronounced in the high latitude regions. Thus, any recommendations must be made specific to region of the ocean. Due to the importance of climate change to fisheries, we propose that we should set up a system for better collecting and analyzing data as global warming progresses. Many types of biological, physical, and geological data are needed to better predict the future climate of various regions. In particular, we advocate the monitoring of temperature, salinity, pH, gas solubility, biomass, species population, and current strength and direction in order to look for trends that would allow us to better predict the future climate of various regions. Also, in particular, more work has to be done to quantitatively determine how fish populations react to climate change. As these data are monitored and studied over longer time periods, more concrete trends should be discovered.
Once trends have been determined, the plan for fishery conservation would then be modified in order to counteract whatever effects were being caused by the climate change. For instance, assuming our best predictions to be true, ecosystems would likely be able to support a smaller population of fish than they do currently. As soon as this realization comes about, restrictions must be changed to fit the reality of the situation. These changes could be made to a number of different restrictions such as technological restrictions, taxes, or closed areas. These changes should reflect the fact that the level at which fish can be harvested sustainably is lowered. The most important aspect of the plan with respect to climate change is that it has to modifiable, so that we can be constantly improving our approach as we improve our understanding of climate changes effects. This approach, however, requires a great improvement in our understanding of fish population dynamics in order to be effective.
Examples
Here are some predictions for possible future effects of climate change on certain areas:
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A specific study of Orange Roughy, a highly fished species in deep waters in and around Eastern Australia and Western New Zealand (see maps below) is a salient study to illustrate the effects of climate on specific fisheries. Orange roughy typically live in geographic features in the ocean, such as seamounts and canyons, as shown by these two illustrations. They consume other fish, squids and crustaceans (Biology of Orange Roughy, 2002), which in turn consume Planktonplankton. The ocean climate around this area of the ocean is dominated by the East Australian Current (Cai et al., 2005). This current is expected to increase with projected climate change; on first glance, this appears beneficial for plankton, and by extension, Orange Roughy via intermediate trophic levels. However, this portion of the ocean is also expected to increase by roughly 2 degrees C (Haysa, Richardsonb, & Robinson, 2005). As a result, plankton may be displaced from their correct temperature, and since they can't migrate to other areas, they may be depleted. Monitoring needs to be implemented to discover how plankton levels are being affected. Also, the increased circulation should increase flow of nutrients to the deep ocean in Orange Roughy's habitat. Therefore, much monitoring needs to be implemented to discover how these factors will interact to affect Roughy population.
Western North American Coastal Zone
From 2003-2005, along the Northern California Current, on the West Coast of North America, went through a warming period similar to those related to ENSO, El Nino - Southern Oscillation events, however, southern waters were in an ENSO neutral state, accompanied by delayed upwelling and a lower plankton biomass (Peterson, 2006). Paleoclimatic data suggest that upwelling in the California current system is positively correlated with temperature over millennial timescales. Furthermore, upwelling along the California coast has increased over the past 30 years, and these increases are expected to continueyears, and these increases are expected to continue. There is also the possibility, however, of the waters becoming increasingly stratified, which would likely result in a decrease in upwelling. It is also fairly certain that advection should increase in the California current (Harley, 2006). The upwelling could have a beneficial effect on the ecosystem if it is not too strong, but advection would likely have an adverse effect. One study links some of these changes to a decrease in the population growth rates of the northern California Chinook Salmon. The Salmon salmon numbers were negatively effected by increases in sea surface temperature, curl, scalar-wind and pseudo-wind stress, while positively effected by increased seasonal upwelling (Wells, 2007).
Based on this data, we predict that it is likely that the populations of fish in this region will be negatively affected by climate change. This would have to be taken into account and stricter enforcements would be needed to produce the same results that would be expected without climate change (Harley, 2006). This would most likely be done through changing the quotas placed on important species in by changing the number of fish that are allowed to be removed from the region. Technological restrictions and marine protected areas could also play a role. However, if the benefits of the upwelling are seen to be outweighing the harm done, these restrictions could probably be relaxed. Changing restrictions in this area should be relatively easy as there are already species-specific laws enforced in these waters by the Pacific Fishery Management Council (PFMC URL).
Western South America Coastal Zone
Coastal Fishery fisheries off of South America resides at reside in an upwelling zone. This upwelling goes through cycles during ENSO cycles. Mortality rates were highest during EN El-Nino events (Hernandez-Miranda, 2006). There is a chance that there could be a long toward shift in the climate towards the ENEl-Nino, which would most likely have a negative effect on fish populations (Collins, 2005). Another evaluation predicts global warming will ultimately lead to longer and weaker ENSO cycles. This occurs via complex interactions between currents and atmospheric circulation. If the first case occurs and the system shifts in the El Nino spectrum, then the fish populations in this region stand to be much lower than would be expected otherwise (Zhang, 2005). In the 1990's this region underwent several mild to moderate EN El-Nino events, without intervening LN events (IPCC, 2001), perhaps indicative of the first case.La-Nina events (IPCC, 2001), perhaps indicative of the first case (shift toward El-Nino).
Temperature anomolies during an El-Nino event (Image courtesy of CPC ENSO Main Page)
If this trend is the case then it would have to be taken into account and stricter enforcements would be needed to produce the same results that would be expected without climate change. The fisheries in these regions might also take additional hits during elEl-nino Nino years, so additional protection might be required for these years. If the second case happens (longer and weaker ENSO cycles), then climate change will most likely play a much smaller role in the management of this fishery, and plans can be carried out without too much modification for climate change. There is an ongoing debate in Peru regarding the creation of a Marine Protected Area (Working Paper, 2004), which could possibly be used to safeguard fish populations to a greater extent than they would in other regions. ENSO is also linked to changes in weather, which have effects on the terrestrial environment of Western South America. Floods and landslides in Peru during El-Nino years cause an increased mortality rate by 40% (IPCC, 2001).
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These ecosystems also contribute to the livelihoods of coastal communities in Kenya, Mozambique, Tanzania, Madagascar, Mauritius, and Seychelles. The sustainable management of these sectors is crucial to the development of most nations, however, the complexities of marine systems and their associated scientific, economic, social, legal, and institutional issues make it difficult to implement effective management. Despite this, management systems that incorporate stakeholders in planning and implementation of marine protected areas (MPAs) and integrated coastal area management (ICAM) have been established in many WIO Western Indian Ocean countries (Wildlife Conservation Society).
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A proper enforcement of the protection of reserves would achieve conservation of both representativeness (middle) and high diversity areas (edge). If necessary, there should be a collection of reserves that have the specific purpose of improving local yields of exploited species. The sizes of biodiversity reserves should be determined by local habitat heterogeneity and should be designed to maximize their benefit to adjacent areas while minimizing their size.
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Climate change could cause an increase in severe weather, which could lead to an increased amount of precipitation. Costal Coastal fisheries could be effected affected by the increased amount of fresh water coming from the rivers. The "flushing rates" (where the fresh water and saltwater mix) could be effectedaffected. The estuaries are important nursing areas for fish and shellfish. Sea level change could have an effect on coastal erosion, resulting in the loss of costal coastal marsh habitats. Climate change may not have that great of an effect on offshore fish, such as tuna and mackerel, or bottom-oriented fish, such as snappers because they of their mobility. With the increase in temperature of the Gulf of Mexico there is a possibility to shift the "zone of inhabitance" of tropical species northward, which might cause a loss in resources for lower latitude fishing nations. (NOAA fisheries service, n.d) Some examples of fish that are being fished in the Gulf of Mexico are red snapper, mackerel, swordfish, grouper and tilefish. (Fisheries and aquaculture, n.d.) A specific country, Cuba, fishes high-valued finfish and shellfish. (Adams, n.d.)
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The Southern Ocean (Antarctic Ocean) is important to managing climate change with respect to the worldwide ocean because the Antarctic Circumpolar Current (ACC) allows for mixing between the three great oceans. The ACC also serves to buffer Antarctica from the variable climate of higher latitudes (Gille 2002). Furthermore, Antarctic fish have a low tolerance for increases in temperature. This intolerance is due to the fact that in low temperature water, oxygen is more soluble in colder water than in warmer water, so Antarctica fish have a lower capacity for transporting oxygen in their blood, such as via mechanisms including their having fewer red blood cells. that The number of red blood cells possessed by these fish would not be sufficient at higher temperatures (Mark 2002). Since From the 1950's though the 1990's the water in the Southern Ocean has increased 0.17ºC±.06ºC. This , a greater change than the overall ocean (Gille 2002).
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There is evidence of lower salinity in the North Atlantic coming from melting of polar ice caps and diluting the ocean with more fresh water. An increased amount of fresh water could come from glaciers or sea ice melting, an increased amount of precipitation, or from rivers. The freshening increase of freshwater in the oceans could have a damaging effect on the Ocean Conveyordamaging effect on the Ocean Conveyor (currents which transport warm water from the tropics to Northern latitudes on the surface; the water cools as it travels north, and then sinks and travels south again). There are different scenarios for the slowing down of the ocean conveyor Ocean Conveyor between the next two decade or in a hundred years (Gagosian, 2007). There is paleoclimatic evidence for rapid climatic changes as a result of the shut down of the ocean conveyorOcean Conveyor. If this were to happen, the Gulf Stream could possibly be deflected downwards, which would prevent the transfer of warm water from the tropics to the high Northern latitudes. In this scenario the high latitude would go through a very rapid cooling periods that could have devastating effects on the ecosystem (Gagosian, 2007). For this reason we assert that this region should be carefully monitored in order to recognize this trend early. There should also be a significant effort put into maintaining the robustness of the ecosystem in this area. To do this, restrictions placed on the fishery in this region should be higher than they would otherwise be set. If research proves this scenario is not the caseas severe as predicted, or that it change will happen on longer time scales, such restrictions would be able to be scaled back. could be scaled back.
Changes in Salinity in the North Atlantic (B. Dickson, et. al., in Nature, April 2002)
Current Currents in the Northern Latitudes (Illustration by Jack Cook, Woods Hole Oceanographic Institution)
Australia
Studies have shown that coastal waters will warm by up to two degrees by 2030, encouraging fish to move south, threatening marine turtles, and potentially pushing box jellyfish down the east coast. Of all coasts of Australia, eastern-central and southeast domains were the most vulnerable to the impact of climate change. The movement of box jellyfish is particularly alarming because some species of these jellyfish are potentially fatal to humans. Most fishermen are only licensed to catch prawns and shrimp, as amateur fishing bans are already in place (Hannon, 2007).
Scientists are using tropical foreign fish to gauge how fish around Australia and Tasmania will react to higher see sea temperatures. Also, they are trying to learn what smaller fish to feed the native fish in order to produce maximum size and yield. Researches have found that barramundi grow more quickly when fed lupins rather than smaller fish like anchovies. (Barra, 2007).
Another team of scientists studied how the depth of water and climate change related to fish populations. The science team examined 555 specimens ranging in age from two to 128 years, with birth years from 1861 to 1993. Growth rates of a coastal species, juvenile morwong, in the 1990s were 28.5 per cent faster than at the beginning of the period under assessment in the mid-1950s. By comparison, juvenile oreos, a species found at depths of around 1,000 meters, were growing 27.9 per cent slower than in the 1860s. There was no or little change in the growth rates of species found between 500 and 1,000 meters. correlations Correlations for long-lived shallow and deep-water species suggest that water temperatures have been a primary factor in determining juvenile growth rates in the species examined - Banded morwong, redfish, Jackass Morwong, Spiky, black, smooth and Warty Oreo and Orange roughy. In the southwest Pacific east of Tasmania sea surface temperatures have risen nearly two degrees, based on the results of a monitoring program at Maria Island. Coinciding with this has been a southward shift in South Pacific zonal winds, which has strengthened the warm, pole ward-flowing East Australian Current. (CSIRO, 2007).
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Rising temperature of climate change is already noticeable in the deep layers of the Japan Sea and the shrinking ice of the Sea of Okhotsk, while rising sea levels have been occurring along Sanriku coasts and the Pacific Ocean side for the past 100 years. Southern plankton which have never been seen as north northerly as Japan now threatens oysters, shellfish, and sardinesardines, all of which are important to Japan's fishing industry. (Ichikawa, 104-105) The great change afflicted by even a few degrees rise in temperature is evident in the case of bluefin tuna. Able to spawn up to six degrees below its optimal temperature of 26 degrees Celsius, bluefin tuna, however, cannot spawn three degrees above that number. Based on the study and projection of Shingo Kimura, professor of marine environmental science at the University of Tokyo, tuna population, already hurt by overfishing, will be so exacerbated that populations will shrink to 37% its current levels by 2099. As Japan is the biggest supplies of bluefin tuna and given the internationality of the fishing industry, a decline in numbers hurt will also hurt China, South Korean, China, and the US. (Bluefin, 1) In a culture that is based on fishing, Japan faces not just the threat of environmental change but also of cultural change.change but also of cultural change.
Over the past two centuries, the pH of the ocean's surface has decreased by .1, drastically altering the chemistry of the ocean; this trend is predicted to continue with a decline of .3-.5 by 2100 if carbon dioxide emissions continue at 1,000 parts per million (Samuel Bowring (personal communication, November 24, 2007)). The result of increased acidity is more pronounced in the Pacific because of its cold water, which can dissolve more carbon dioxide. Coral reefs are more likely desintegrate at these levels of The increased carbon dioxide from combustion has in turn increased acidity of the ocean by 30%, drastically altering the chemistry of the ocean. In the North Pacific waters, which is the most in general more acidic than other waters because it is colder, older, and absorbs more carbon, coral reef are being tested at saturation points, when growth cannot overcome disintegration due to acidity. (Brenton, 1) In the Indo-Pacific waters, which hold 75% the world's coral reefs, researchers of at the University of North Carolina at Chapel Hill found in surveys found study decline, threatening a decline of coral reefs which threatens tourism, that coastal regions that once found safety behind the buffering reefs, and fisheries. (University of North Carolina at Chapel Hill, 1)
As Royce Pollard of Vancouver, Washington said, "The fish gave us our first indication." (Joling, 1) The effect of climate change on fisheries in many cases is a warning sign of more adverse effects to follow. In the case of Alaska salmon run failures of 1997-1998, Chinook salmon catch were only 43,500, half than that of the catch the year before. Though for For the next year, the Alaska Department of Fish and Game forecasted a catch of 24.8 million, and only 12.1 million were caught. Also in 1997-1998, Alaska experienced a 2.0 degrees Celsius increase in surface temperature and a 1.5-2.0 degrees Celsius increase in deep ocean temperature. (Kruse , 61) Pacific white-dolphins, albacore, walleye Pollock, all southern species, were sighted in northern Gulf of Alaska. A sub-polar phytoplankton known as Coccolithophore blooms appeared suddenly, indicating high light intensity and low nutrients in the water. All these changes, which were already predicted in 1995 by ocean scientists who studied global warming on the Bering Sea, confirmed the need to understand more climate change in Alaska. (Kruse, 60) As a result, the North Pacific Fishery Management Council and the Marine Conservation Alliance have closed US waters in the Arctic Ocean to fishing until enough research is present to understand climate change and until a management regime is put in place for climate change. (Marine Conservation Alliance, 1)
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