At GWC we fully support the need to separate whales and ships in space. All groups agree that this is the best option for preventing whale deaths when possible. This has been done successfully, such in the case of Panama, where the approach to the Panama canal was altered away from the primary whale habitat.
Another approach to preventing ship strikes has been to slow ships down. While slowing ships down does reduce pollution and noise, this strategy does not do enough to save whales. Large vessels cannot maneuver away from whales nor do the whales get out of the way.
We strongly advocate for the need to separate whales in time — restricting traffic at night in areas where whales are more likely to be feeding or resting near the surface. This new study shows why.
While dive depth varied among animals based on where prey was located, whales spent a high proportion of their time closer to the surface where they would be more vulnerable to ship strikes at night than in the day. This was most pronounced for blue whales where vulnerability was twice as high at night compared to the day.