More research needs to be done on why fish die during the fishing process. Currently, there is a limited amount of information on why fish are dead after they are pulled from the ocean. The research needs to be directed towards the different stages of catching fish to see whether fish are dying from entanglement in the nets, smothering by other fish, being pulled to the surface to quickly, shock, or another unknown cause. By researching this, fishing technology can be improved to reduce the amount of death.
A great deal of research will be necessary in order to better understand the role of climate change to fishery management. First, more research must be done on the response of specific species and fish populations to climate change, since there has been difficulty in discerning the effects of climate change from other factors controlling fish populations (Harley, 2006). This can be done through taking samples of fish, or through fish tagging (see below). Global warming only gained credibility a few decades ago (IPCC, 2001), so there is no research on the long-term effects of climate change.
Second, research must be done in order to improve our understanding of fish population dynamics. This will be necessary in order to effectively change fishery management to respond to changes in climate. Work also must be carried out to improve our capability of prediction the change in global climate and effects on specific regions. As models become more refined, the uncertainty in predictions should decrease. This would improve our ability to make preemptive changes in policy.
Most importantly, there should be constant monitoring and analyzing of data on the oceans in order to spot trends in climate change and their effects. Important data which should be kept track of include water temperature, salinity, pH, O2 concentration, biomass, primary productivity, and current speed and direction. There are technologies in place for monitoring many of these. There has already been work on a device used to measure ocean temperature is called an Autonomous Lagrangian Circulation Explorer "ALACE" float (Gille, 2002). The basic operation of a float is to dive to a preset depth, record information of a set number of days, in the study it was 10 to 25, rise to the surface and communicate the information with a satellite, then repeat the process. Newer floats can also give temperature-depth profiles of the ocean as the ascend/descend. The sensors on the floats were calibrated to thousands of a kelvin, and only degrading by .001 K/year. Also there is no reason to believe that sensors for other quantities, such as salinity, a possible way to measure fish number, could not be added to a diving/surfacing float framework (Gille, 2002). Primary productivity can be measured by spectrometers placed in, such as NASA's Moderate Resolution Imaging Spectroradiometer, "MODIS" (NASA, 2003). There also needs to be a central collection of this data so that the different aspects can be analyzed in tandem. This data should also be open to public access, so that many different research groups all over the world would be able to help analyze it. It would also be beneficial to have a centralized group to delegate tasks to certain institutions, which is why our proposed implementation solution, a treaty, calls for more research (as does the Law of the Sea and the UN Agreement on Fish Stocks).
We have decided that a system based on passive integrated transponders (PITs) will be the best method for tracking fish populations in the near future. The PITs that we intend to use are small, 10mm diameter glass cylinders that are injected into the fish (Roussel et al., 2000). Because PITs are passive, they have a nearly indefinite lifespan. The tags are read by an antenna, which records the unique identifier of each tag. It is suggest that information should be collected on a regional basis, and that our surveys should transcend national boundaries.
Our plan calls for teams of scientists and out of season fishermen to work in tandem to tag fish. First, the fish are caught by one of the two following methods. For initial tagging efforts in an area, we suggest a short, slow trawl using modern, environmentally friendly nets link to net technologies that do not destroy the ocean floor. Trawling in this manner keeps the total number of fish caught low while still collecting samples of most of the fish present. The net is then raised slowly to avoid killing the fish from the swift change in pressure. After being raised from the seafloor, the fish are brought onboard for tagging.
For surveys intended to supplement data for a particular species or group of fish, much more selective and environmentally friendly capture methods, such as hand lines or traps, can be used. Once caught, each fish is brought to the boat deck for tagging.
The tagging process is relatively quick; current machines can automatically inject tags into more than 150 fish per hour (Lucas & Baras, 2000). After tagging, each fish will get weighed and measured for length. The length, weight, and identification number of the fish is combined with GPS data from the ship and then uploaded to a central database. The fish are then returned to the wild.
It is important to note that our application of PITs will be novel. Currently, PITs are used for tracking freshwater fish; the major limitation is the range of the antenna. Current antennas can only read PITs from a distance of about 18 cm. This short range has restricted the application of PITs to environments where fish will be likely to pass within a short range of a possible antenna site, typically a fish ladder or shallow stream (Lucas & Baras, 2000; Roussel et al., 2000).
Naturally, it would be impossible to fill to oceans with antennas with such limited range. To overcome this difficulty, we propose placing the antennas in the processing equipment on fishing vessels. We envision that as the fish are taken out of the sea and moved to storage, they will pass through an antenna device that will record the identification number of the fish and the location of the boat. When the fish arrives at the processing facility, either onboard a factory trawler or on land, its identification is checked again, and automated weighing and measuring machines will add length and weight data to the previously uploaded catch record of the fish.
Our plan will vastly increase the amount of data available to both fishermen and scientists. Because our plan does not require any additional effort on the part of the fishermen once the antennas and software are installed on the boat, the program will be able to run without impeding fishermen at work. Current tagging projects require manual removal of tags and fishermen must send the tags back to a central agency. So our plan can replace this cumbersome process.
Because our plan primarily uses trawls to collect specimens, it is able to benefit from the full spectrum of organisms that trawls attract. The survey can be fine tuned, however, if more specificity is warranted.
The biggest benefit of our plan, however, is the increase in available data. The purpose of conducting such expensive and extensive research is to develop a significant increase in the knowledge about fish, their migratory patterns, and their growth. Because each re-catch results in a new data point with a specific weight, length, location, and time, there will be a large amount of data about to where and how fast fish are migrating, as well as their rate of growth. This type of information will be particularly useful when scientists are trying to determine the best locations for Marine Protected Areas (MPAs) link to MPA selection. With this information, scientists can work to protect areas where growth is most optimal.
As with every other survey method, our proposal does have some drawbacks. The primary concern is the price of PITs; they cost nearly $4 per PIT (Lucas & Baras, 2000). Our plan hinges on tagging numerous fish, which could quickly drive up costs with expensive tags. Additionally, the cost to upgrade existing equipment to handle the new antennas and weighing and measuring machines will be considerable. Finally, there will be costs associated with running the research vessels that tag the fish. Together, these costs combine to create an expensive program.
There is, however, light at the end of the tunnel. We expect the price of PITs to drop drastically as demand due to tagging projects increases. With additional demand will come more competition, and more competition will lower tag prices. Operational costs will not have to include the money used to purchase and install the antennas, scales, and measuring devices; these are onetime fees.
We recognize that even with substantial reduction in PIT prices there will be many nations that are unable to implement PIT tagging on a large scale. Our alternative plan outlines the minimum surveys that we feel are necessary to maintain a proper level of information about the health of fisheries.
The alternative plan consists of a combination of trawl surveys and SONAR readings. While we have acknowledged that neither technique is perfect, we feel that they are capable of providing essential data about the health of fisheries. In areas that do not have accurate estimates of the species present, a survey trawl should be conducted first. This trawl will serve to provide basic information on the composition of the fishery and rough estimates of total biomass. Once the survey trawl is complete and there is accurate data about fish types, SONAR scans will be taken regularly to monitor the biomass of the area. With several advances to SONAR on the horizon, this portion of the survey should only get more accurate with time (Brehmer et al., 2006; Gerlotto, Soria, & Freon, 1999). In the event that SONAR scans or catch data indicate a major disruption in the stock, another survey trawl should be conducted to ensure that stock composition data remains up to date.
While this combination of SONAR and trawls will not yield nearly the amount of data provided by PIT tagging, it will allow stock managers to understand the basic composition of their stock and have estimates of the biomass of the stock. The international treaty in charge of implementing this solution will direct funding toward nations that cannot afford high quality tracking methods so that they may improve their tracking technologies.
Scientist currently use trawls, SONAR, and tags to track fish. We propose that new tagging surveys be implemented to provide information on migration, stock growth, and fish characteristics, such as length and weight. When a region cannot afford tagging surveys, we propose an alternative plan that will provide the essential data about stocks to their managers.