You might think it would be easy to tell apart the largest animals on Earth. But recently, as we watched several great whales feeding on spawning sardines off the southern Pacific coast, between CorcovadoNational Park and Caño Island Biological Reserve, we debated for hours about what species we were looking at.
The whales, including a very small young one, had no interest in us, only in slicing through sardines, gulping down a thick soup of sea life. I was guiding a blue-water pelagic ecosystem diving trip, but we stayed on the boat to watch the fast-moving whales surrounded by marine birds of more than a dozen species, thousands of yellowfin tuna and several hundred pantropical spotted dolphins, all enjoying the feast.
When the whales and dolphins moved off, we slipped into the transparent blue water next to the boat to see if any other interesting beasts were lurking down there enjoying the banquet.
We were not disappointed. A baby whale shark, only five meters long, swam around us slurping sardine spawn with reckless abandon.
A giant manta about as big as a car swam by, mouth flaps open for feasting. She had two giant remora suckerfish hanging on for a free ride. We saw hundreds of these giants throughout the day, many of them flying meters out of the water and landing with a sound like the crack of thunder. But there was still more to be seen.
While we were resting in the boat, a tiger shark about four meters long circled close enough to touch. Nobody got in the water.
Later, we did get in with a two-meter dusky shark and some olive ridley turtles.
Then the whales came back, and we marveled at their size and wondered again what species they were. Sei, fin and Bryde’s whales are hard to tell apart when all you see is their backs. Noticing that their blowholes and dorsal fins were not visible at the same time during surfacing, we reckoned we were watching fin whales, the second largest animals on the planet after the blue whale – and they looked it.
A few days before and a few kilometers away, Cristian “Shaggy” Solano, captaining a trip for Aguila de Osa Lodge in Drake Bay, reported seeing a group of thousands of spinner dolphins with whales and the same outrageous congregation of other marine life. Sadly, he also watched a giant tuna fishing boat plow through the partying dolphins and corral them with a helicopter, explosives and speedboats.
The commercial fishers did this because vast schools of giant tuna usually stay underneath smart hunting dolphins. By corraling the dolphins at the surface, the fishers corraled the tuna underneath.
Then they dropped a net bigger than a city block into the waters teeming with life.
After seeing a few dolphins killed by the operation, Shaggy’s clients wanted to leave the horrifying spectacle of greed and myopia – all within sight of famed CorcovadoNational Park and Caño Island Biological Reserve waters. Sadly, this is a common occurrence here in the richest waters of the “rich coast.”
Diving conditions in the Osa’s blue-water ecosystem continue to be outstanding. With the rains seemingly ending early, dive conditions should be improving to very good at the rest of Costa Rica’s Pacific dive sites, where recent reports are of slightly murky water with visibility at about 12 meters. The Caribbean’s rains have rendered visibility to less than five meters.