Whale strikes by boats undercounted, study says
Actual numbers could be 15% higher
A new study suggests that nearly 15% of the protected humpback whales that come to feed every spring in the southern Gulf of Maine have been struck by boats and other vessels — putting both boaters and the sea mammals at risk.
Researchers believe their findings, which appear in the most recent issue of Marine Mammal Science, are likely underestimated because the study does not account for whales that actually are killed in ship strikes.
The analysis is based on injuries to 624 individual whales photographed between 2004 and 2013 in a body of water just off the coasts of Massachusetts, New Hampshire and Maine.
Multiple reviewers evaluated 210,733 photos for five categories of injuries consistent with a vessel strike.
Of the 624 individual whales reviewed, 92, or 14.7%, had injuries attributed to at least one vessel strike. A total of 149 injuries were documented, according to the study.
Most of the whales had four or fewer vessel strike injuries. Seven whales had at least three vesselstrike injuries, and two whales had at least four injuries.
Researchers for the Gulf of Maine study point out that, while humpback whales are listed as endangered under the U.S. Endangered Species Act, there currently are no regulations or guidelines in place to reduce the likelihood of collisions with vessels in their vicinity — except those actively engaged in whale watching.
They hope that their research, and other long-term studies, can help regulators develop new guidelines on boat traffic, and better assess the health of the humpback whale population.