| Summary: | Collisions with ships are one of the leading causes of death for whales and are increasing. It is imperative to eliminate or greatly reduce whale mortality caused by ship strikes because even a few deaths may have a significant impact on severely endangered species, such as the North Atlanticright whale (Eubalaena glacialis). There are numerous proposed causes and solutions, but none that will completely eliminate the problem. New avenues must be explored. Causes include cetacean biology, as well as anthropogenic. Biology related factors that may affect collisions include species, gender, physical condition, age, activity, time of day, season, changes in food location and availability. Suggested anthropogenic causes include increases in ship traffic, ship size and speed, hull configuration, and propellers. Ocean noise is considered a multi faceted factor. Sound is the primary form of sensory perception for most cetaceans. The naturally noisy ocean is increased by anthropogenic sources of noise which have increased over the years. Of greatest concern is active sonar used by a variety of users, but of most impact are the navies around the world. The U.S. Navy has been involved in ongoing disagreements regarding their use and the detrimental effect of sonar on cetaceans. Sonar is believed to disrupt their normal behavior and hearing, making them more vulnerable to ship strikes. From the plethora of data, a “typical” whale strike can be constructed. The profile shows the following characteristics: a young fin whale (Balaenoptera physalus) injured by blunt trauma likely carried into port on the bow of the ship in theMediterranean Sea. Proposed solutions include an audible whale deterrent, changes in vessel design to reduce noise, and reduction in noise producing activities. It is believed that if whales can be located, they may be avoided. Thus, solutions for locating whales include tracking whales by tagging, electronic monitoring, passive acoustic detection, active sonar, radar, and infrared detection. Changes in ...
|
|---|