One solution the paper highlighted involves setting aside more and larger areas of the ocean that are safe from industrial development and fishing. (sciencedaily.com)
The sea ice extent measure is broader, including areas of ocean where ice covers 15 % of the surface area. (earthtimes.org)
Nowadays the cost of covering a broad area of the ocean with multiple receivers to locate marine mammals or underwater vehicles based on the acoustic signals they produce is excessively high. (sciencedaily.com)