Sperm whales and nudibranchs! From the gigantic and, it must be admitted, rather plain, to the small and splendid (especially for a slug!), we had a marvelous day of Mediterranean marine life as we cruised from Iberia toward the Balearic Islands.
Our morning at sea was relaxing and restful, featuring a presentation by Karen on the geologic history of the Mediterranean Sea, an excellent introduction to the natural history of this unique body of water. Some of us may have been thinking about a nap after lunch, but any such plans were shattered by a sighting of sperm whales! Following a quick consultation on the bridge, the ship made an about face and cruised slowly back through the area where the whales were first seen with all eyes carefully scanning the horizon. Patience paid off when Shaun spotted the unusual angled blows again and we slowly approached a group of three animals resting and breathing at the surface. Drawing closer, we could clearly see their characteristic blunt heads and off-center blowholes. As mentioned above, sperm whales are not the loveliest of marine mammals, with wrinkled gray skin and a somewhat ungainly shape, but they are certainly fascinating creatures. The largest of the toothed whales, they are also the deepest diving of all mammals, making hour-long plunges to depths as great as 10,000 feet! The water beneath us this afternoon was nearly a mile deep and as the great whales lifted their flukes to begin a dive we wondered about the strange, dark world they were entering.
Later, at recap, I presented an underwater video that I had shot at Calahonda on Spain’s Costa del Sol the previous day. This dive was on a rock reef inhabited by bright schools of wrasse, sunset-orange sea stars and gorgeously colored nudibranchs. These, surely the most lovely of slugs, have many amazing adaptations to life on the reef, including the ability to consume toxic sponges and make use of the poison in their own defense. Their brilliant colors and psychedelic patterns probably serve to warn predators of their adopted toxicity.
The Mediterranean, surrounded by developed and developing nations, has had some hard times and experienced fairly serious pollution, but in recent decades conservation policies and clean-up efforts are beginning to turn the tide, returning these beautiful blue waters to a healthy condition. Today we had a wonderful experience of how rich the biology of this historic sea can be.
