Sunday, May 29, 2011

Circle of Life

Yesterday morning, in White Bay, Peter Island, BVI, Aidan enthusiastically woke me up around 6:15am to show me all the action and new creatures he's been watching off our bow. He told me about a fish he saw, with eyes "this big!" indicating a circle with his hand, about 5cm in diameter. Once I dragged myself out of my berth to join him, I was amused at his ongoing monologue about what he was witnessing. "Oh, oh, here comes some action!" he would call out as he pointed to some approaching ripples in the water. He'd follow them from stern to bow, "It's like there's a life circle around our boat! Maybe we still have some tiny shrimp on our hull, tiny fish are eating those shrimp, small fish are eating the tiny fish, medium fish are eating the small fish, and that big fish is eating them all."

And we were treated to another display of a local ecosystem in the Caneel Bay anchorage last night. Austin had stepped out to the swim platform to rinse out the pasta pot, then rushed below to invite everyone to come out to see the large tarpon at the stern. Skye got a flashlight and shone it at the fish ... many fish (we counted about 9 of them) ... and boy, were they big! Each one was about 1-1.5m long, their scales shone silver in the night, their mouths turned up in the distinctive way tarpons' mouths do, and their eyes looked like yellow glowing golfballs floating in the black water. We could see little splashes all around the boat, caused by smaller and smaller fish which the tarpon appeared to be eating.

Then we were surprised to see a new participant in the feeding frenzy -- a night creature in flight. Could it be ... a bat? A fruit bat*, as Austin surmised. Its wingspan was about 50cm, and its body seemed bigger than my fist. Eventually, there were about 7 bats feeding on insects at the water's surface. We wondered if some of the smaller fish may have been catching the same insects as the bats, or were the bats eating small fish? The bats' wings would occasionally splash in the water, and Austin saw long claws on their feet, so we were curious to know what they would be eating. But they were probably responsible for keeping the mosquito population down on the boat last night, so "Thank you, bats!"

This spectacle reminded me of a summer evening at Diefenbaker Lake when I was a teenager, visiting with family at their summer cottage. About 10 of us were sitting on lawn chairs on the porch. Mosquitoes started to pester us a bit, then a swarm of dragonflies came to eat the mosquitoes. One dragonfly lit on the shoulder of my cousin, Brent, who responded with a wide-open-mouthed call of surprise. All of us burst into fits of laughter, and within minutes, several birds swooped around the porch to pick off the dragonflies.

*I found this information on the fauna of the Virgin Islands:

Bats are said to be the only animal that is native to the Virgin Islands. Bats can be found in caves in less populated areas of the islands and are sometimes spotted flying at night. It is not uncommon for several dozen bats to roost together in a cave. They are primarily insect eaters and nectar drinkers however there is a fisherman!

The fisherman bat is a threatened species in the Virgin Islands. The bat roosts in caves near the sea, woodlands and in roofs of old houses. Through the use of echolocation or sonar, the bat detects ripples caused by fish swimming close to the water’s surface and uses it’s long, curved claws to catch them, thus the name fisherman bat. They are good swimmers and they use their wings as oars. The species' numbers have greatly declined because of coastal development.

According to another web source, fruit bats only eat fruit - not insects. However, as one often experiences on the world wide web, there are conflicting reports. This article on the bats of the Virgin Islands states that fruit bats control the insect population on fruit farms. The article also describes the "fisherman" bat as the gender-neutral name, "fish-eating" bat. It's cool to think we could have been so close to an endangered species, that seems to be thriving in this environment.

See this National Geographic video on the fishing bat.

I'm eager to go to the National Park Service headquarters today, to see about the interpretive centres and hikes offered here. Other cruisers have told us about this, and knowing they are part of the Unites States Park Service, we expect loads of interesting information, equalling what we are accustomed to in our great Canadian National Parks.

1 comment:

  1. The 'circle of life' ---- a wonderful decription of what goes on around us all the time but most of the time we just don't notice. Aidan, you're really in tune with nature!!
    Tarpons --WOW! I just checked some images of these monster fish -- tail walking! What a sight. I see that anglers like to catch them but I wonder if they're any good to eat? Have you been fishing much, Austin?
    Looking forward to hearing about your experiences in the Nat Park... It looks extensive.

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