Whales of Mártir
Isla San Pedro Mártir, Gulf of California, México

Lonely Isla

Isla San Pedro Mártir (Mártir, for short) is located near the middle of the Gulf of California about 20 nautical miles (~23 land lubber miles or 37 km) south of Isla Tiburon. You're right. The middle of a deep gulf is a strange place to put an island. But there it is.

For the Birds

Like most islands in the gulf, Mártir is not the lush and inviting tropical island of popular cinema. It is a desert island in the true sense of the word. About 2 kilometers long the seemingly barren island is surrounded by steep cliffs and few (safe) anchorages. Cardón cacti (Pachycereus pringlei) ) dominate the floral assemblage. Even over the roar of your motorboat engine you'll notice another sign of life; the cacophony of thousands of birds like the Blue-footed booby (Sula nebouxii) raised in chorus. That's assuming the gnats haven't found you first.

How Did It Get There?

If you're the sort that notices rocks as you cruise around the island in your 25-foot luxury yacht, you'll see that Mártir is formed of tilted layers of volcanic rock. That and a heavy coating of guano. Mártir started out as part of Baja California several million years ago before the gulf split and seafloor spreading opened the abyss. But that's another story.

A Thriving Industry?

In the late 1800s guano was mined here for several years. Exactly how much and for how long is not known because historical records are rather hard to come by. Guano was probably scraped from rocks and piled on rock ledges for transfer to a ship. These ledges are still visible over much of the island. As you might expect, scraping every exposed rock on the island for several years probably had a serious impact on plant and animal life here.

Bring on the Whales

It's hard to spend much time in the gulf without catching a glimpse of a rorqual whale surfacing for air. It's usually very difficult (some might say impossible) to tell, say, a fin whale from a Bryde's because you only get a fleeting glimpse of their back and dorsal fin . A blue whale, on the other hand, is like panning your first gold nugget. When you see it you'll know it.

It's All in the Cards

Underwater contact with rorqual whales is usually a chance meeting. For one thing, whales tend to be pelagic (deep water); not the sort of place humans commonly hang out. When you see a whale surface, how do you know when and where it'll come up again? You don't. So you either spend a lot of time floating around waiting for a whale to happen along or you get lucky and they find you.

Breakfast Time?

One of the chance type of whale encounters occurred one fall morning off the south end of Mártir. We were anchored in a sandy bottom cove in 10 meters of water and a few hundred meters off shore. Surprisingly, a whale surfaced between the boat and the shore. Fifteen minutes later another whale (or maybe the same one) surfaced moving in the same direction.

Waiting Game

A few minutes later found me on SCUBA finning along the sandy bottom where I'd seen the whales pass earlier. Underwater visibility is usually estimated as the distance you can see before an object disappears. Here it was no more that 5-7 meters; the water was clouded with small invertebrates. Schools of grouper casually browsed through the floating meal. Could the mass of invertebrates be what lured the whales into the shallows? All that remained was to wait and see if they were still swimming their earlier path.

Close Encounters

Nothing makes your heart leap more than the first time you turn around to see a Bryde's whale (Balaenoptera edeni) emerging from the blue-green gloom 10 meters away. I caught three more passes on videotape in the next 45 minutes before chilly water and low air prompted my return to the boat. The whales were not feeding on any of the passes observed. I was joined by a curious California sea lion (Zalophus californianus) shortly before the last pass. The sea lion's hasty retreat warned me of the whale's approach. We did not see the activity repeated during the remainder of our visit to the island.

Posted 9/1999