Unintentional entrapments of non-target species such as whales were usually associated to improper fishing management. But now, a study has noted the potentials of eye problems causing whales to get tangled on fishing nets. It seems that they cannot clearly see what's right next to them.
The case of entanglements of baleen whales on fishing gears was the focus of a research conducted by Florida Institute of Technology. Based on the results of the research, they have found whales have difficulty seeing especially in bright lights, making them vulnerable to entanglements to fishing gears, which are known as one of the major causes of their death.
Mutation of the cells was traced as the culprit behind the case of the baleen whale. According to Florida Institute of Technology professor Michael Grace, doctoral student Lorian Schweikert, and University of Tampa assistant professor Jeffry Fasick, the results imply that the mutation may further cause harm to the whale through entanglements.
To further understand the mutation that happened, Grace's team tried to clone and sequence the corresponding gene responsible for the cone opsin protein which helps in the provision of a good color vision. Compared with humans who have different color vision genes, whales are known to have only one.
After the analysis, the results were compared. It was noted that the bowhead whales do not actually possess color vision genes, but rather rod cells which are the light detectors that operate in dark conditions.
"Cone cells are normally required for vision in bright light. With only rods, right whales may have a very poor vision when they surface to breathe. This may make it difficult for them to avoid entanglement in fishing gear -- one of the leading causes of death of these critically endangered animals," Scweikert explained in an article.
But though this is the first documented actual complete loss of a mammal's cone-based light detection, the groups emphasized that their study also suggested that mutation of the cone opsin may eventually improve the whale's vision in dim light. "Understanding sensory systems in critically endangered species opens a window that may help us better understand how to protect them. It's a fantastic bonus that analyzing whale vision eyes may help us better understand how our own eyes operate," Grace said.
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