Killer Nets

Fishing is a way of life for millions of people around the world. It can be a personal means of nourishment or a source of income in which to support one’s family. It is one of the oldest occupations and as history has progressed the technology of fishing has developed immensely. Harvest is now much more efficient with larger yields and minimum workforce. This can be seen as positive, because as the population of our earth increases so does the demand for food. With this technology, however; come questions that we must ask ourselves: has this technology become more detrimental then beneficial? Have we gone too far? How much is too much to be taking from the earth’s resources and at what cost to the aquatic populations?

Fishing nets and equipment of large operations have resulted in mass amounts of bycatch, especially with sea mammals. A recent report was published by Kyung-Jun Song, Zang Geun Kim, Chang Ik Zhang and Yeong Hoon Kim about the entanglement of Minke Whales. What they did was track and investigate the number of Minke Whale deaths due to fishing gear entanglement between 2004 and 2007 in the East Sea of Korea. 214 Minke Whales were studied, all of which had drowned due to their entanglement (Song et al. 2010).

Witnesses would report the entanglements to the marine police agents. The agents would then record the date and location of the entanglement and they would also determine the cause of death. If it was determined not to be a natural cause and was an entanglement then the Cetacean Research Institute (CRI) of the National Fisheries Research and Development Institute of the Korean Government would do a more detailed report (Song et al. 2010). Their report would include the species, length, sex and the type of fishing gear involved in entanglements. Finally all the information was analyzed to confirm whether the data that had been collected was true. They did this by comparing the witness statements, photographs, and by looking at the whale carcasses (Song et al. 2010).

This study was not just to determine the number of Minke Whales that were dying, but also to determine what types of fishing gear was causing the most deaths, how the whales died and how far from shore the whales became entangled. What they discovered was that for the most part the entanglements were caused by either set nets (35.0%), pots (31.3%), or gill nets (30.4%). the rest of the entanglements were caused by bottom trawls, purse seines, and trawls (3.3%) (Song et al. 2010). The mouths of the whales was where the majority became entangled. The tail was also a body part that became entangled and in some cases the whales drowned in the fish net chambers. The majority of the mike whale entanglements happened 10 nautical miles from the shore (86.5%), and the depth of water where the entanglements happened was between 10 and 220 m (Song et al. 2010). The average size of the whales that were caught in each type of fishing net was also reported. All this information was recorded and analyzed in hopes that it will someday help minimize the loss of whales.

The authors of this journal claim that more research should be done on the Minke Whale deaths. Research should be done to explain how these entanglements effect the population of the Minke Whales and their migration. They hope that their report can be used as a base for the further conservation of Minke Whales in the East Sea of Korea. It could and should also be useful in the process of modifying fishing gear to limit the number of whales that are dying. This report was in a very small area on only one species of whale and if the number of deaths that are happening due to our technology are as large for other species as they are for the mike whale then we have a serious problem and it is only going to get worse. The question we must ask ourselves is have we gone too far? If so, will we use the information that scientists and other dedicated people have collected to change our ways before we drive more species to extinction?

By Tara Wilson

References:

Song, Kyung-Jun, Zang Geun Kim, Chang Ik Zhang, and Yeong Hoon Kim. "Fishing Gears Involved in Entanglements of Minke Whales () in the East Sea of Korea." Marine Mammal Science 26.2 (2010): 282-95. Wiley Online Library. 7 Sept. 2009. Web. 12 Oct. 2010. http://onlinelibrary.wiley.com/doi/10.1111/j.1748- 7692.2009.00340.x/full.