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