With an ever-growing industrial and global economy, there is a lot more traffic through the ocean’s waters. With so many disturbances, many aquatic animals and ecosystems are being negatively effected, namely the whale population. Whales are the largest mammals that occupy the ocean. Extending to sometimes upwards of 75 feet, they are more likely to come into contact with the many intrusions that humans impose on the ocean. According to a recently published article in the Conservation Biology journal, six out of eight studied whale species along the east coast of the United States are endangered under current United States and Canada legislation.
Between 1970 and 2009 there were 1762 whale deaths, which included 8 different species. Scientists determined the cause of death for 43% of the mortalities. Of the 43%, 67% of deaths were caused by human interaction. Entanglements in fishing gear and vessel strikes were the two main reasons for the deaths of these whales. Despite the legislation that has been passed in order to prevent these types of human-related deaths, whales are still dying. This study assesses the mitigation instilled by these laws.
Scientists used a mathematical model, PBR (Potential Biological Removal), to assess the sustainability of the level of human-caused deaths. With these statistics, they were able to see which species was the most affected by the mortalities, and in result, need more care.
From the mortality records, scientists classified the deaths into categories of age, sex, date, location, length and presumed cause of death. To classify the deaths of the whales, necropsy tests were performed on deceased whales. If evidence was found of a human related death, this was classified as a “serious injury”. The other two categories were “nonhuman related” and “unknown”.
A limitation that presented itself throughout the project was the uncertainty of data coverage for all of the whale mortalities. The article mentions that despite many efforts to spot and document carcasses, a considerable amount of deaths are not seen. Also, the fact that many vessels did not follow the laws passed by Canada and the US did not facilitate the decrease in whale mortality from human related causes.
From the results, 66.9% of known deaths were due to entanglement of fishing gear. There were not many blatant trends for age, sex or specie. However, there was a spatial trend in the whale mortalities in the mid-Atlantic coast. The Canadian and US laws did not produce the amount of change hoped for. For the future, this study suggests that conservation efforts should base conservation efforts more on region. That is, if a certain region on the east coast experiences more deaths, no matter which specie(s), salvation efforts need to act there first, instead of assessing overall numbers within species. Also, since only 20% of vessels at sea complied with the conservation legislation, these laws should be more strictly enforced. Scientists concluded that in order to accurately gauge risk management and conservation efforts, knowing the cause of death is crucial.
This study is important to conduct on a regular basis, in order to ensure that the ship industry is complying with legislation and regulation, but also to keep track of the endangered whales. Assessors of this study can also use this evaluation as an opportunity to make recommendations and delve into the core problems that need to be dealt with. Since whales are aquatic animals, they are not seen often and therefore thought about less frequently. If this study continues to be conducted on a regular basis, the government and private organizations will be able to be well informed, and can better compute their conservation efforts.
Van Der Hoop, J. M., Moore, M. J., Barco, S. G., Cole, T. V.N., Daoust, P.-Y., Henry, A. G., McAlpine, D. F., Mcllelan, W. A., Wimmer, T. and Solow, A. R. (2012), Assessment of Management to Mitigate Anthropogenic Effects on Large Whales. Conservation Biology. doi: 10.1111/j.1523-1739.2012.01934.x