Sperm whales are masters of this discipline as they may dive to depths of 2000 meters, holding their breath for an extraordinary, 1.5 hours. We have been surveying a relatively unknown area in terms of whale and dolphin species, and have been thrilled to encounter several groups of sperm whales. Some have been in tight clusters of eight to ten animals, others spread out in small groups of three and four, as well as several individuals in loose associations. It has been particularly interesting to collect acoustic recordings, or vocalizations from these diverse groups, differing in compositions of abundance, sex and age. As a result, populations of many wild fish and shellfish are rapidly declining, while production of aquaculture is increasing.
Aquaculture is the farming of marine and freshwater species in captivity.
Alone, this acoustic array gives us very good stereo sound from the sea surrounding the boat. For hundreds of millions of years, sharks have survived virtually unchanged and unscathed, ruling supreme in the world's oceans. Unfortunately the party's now over for these predators. Late maturation and low reproduction rates makes them highly vulnerable to over-exploitation. Sometimes, hermit crabs may pull one another from desirable shells.