Isla San Marcos and Whale Watching, Gulf of California

The sun had barely cleared the horizon when our Expedition Leader sighted a very large blue whale. It seemed to be on a course to Isla San Marcos and we weren’t able to spot it again. But we did see a couple more blows of an unidentifiable whale in the distance.

Isla San Marcos was our next stop. This is the only island in the Gulf of California that has a settlement of about 700 permanent residents. Most of it is girdled by rugged cliffs with sand or gravel beaches. The southwest portion is covered with huge deposits of fossiliferous marine sediments and gypsum that dates from the lower Pliocene.

A short distance from our landing on the beach, we discovered the active nest of a pair of ospreys with a juvenile. One of the adults aggressively cleared the air space above the nest, keeping away the common raven. The rugged shore beyond the beach looked particularly inviting with lots of crevices and pockets, perfect for our kayakers to explore. It also looked like an ideal spot to snorkel and soon we were happily splashing through the surprisingly warm and clear water. Large pinnacles of rock rose up to the surface surrounded by clouds of sergeant majors and scissortail damselfish. Bicolor parrotfish played chase with each other and a solitary Panamic green moray decided to take a bold swim out in the open. This fish is primarily nocturnal and hides in the crevices during the day becoming an active predator at night.

By noon, we were joined by a member of Greg Marshall’s team, the inventor of “Critter-cam.” “Critter-cam” is a device that can be attached to the bodies of marine mammals without harming them or changing their natural behavior. Besides recording images, it also provides other important data such as water depth and temperature. It is a great tool that can allow us a more personal look into the every day lives of marine mammals such as the sperm whale. Greg Marshall, along with the National Geographic Society, will be sharing their findings with us for the next seven weeks. After an enlightening presentation by Mark Thorpe and a look at the “Critter-cam,” we were ready to find a sperm whale!

As we cruised along slowly towards Isla Tortuga, we were entertained by the aerial displays of the wing flapping Mobula rays. A small group of bottlenose dolphins joined our ship, but soon lost interest only to be replaced by very curious short-finned pilot whales. This species is pan tropical preferring warmer waters unlike their relatives, the long-finned pilot whales. One sure way to tell the two apart, as told to us by one of our naturalists, if you are wearing shorts when you spot these whales, it is the short-finned whale that you see. Even after slowing down and stopping the movement of our ship, a group of about fifteen individuals lingered as if to get an eyeful.

After saying goodbye to our whales, it was time to continue with our journey through the Gulf of California.