Monday, August 13, 2012

Other sightings

We don't always just see dolphins and whales.  Today was a good day for sighting some other ecologically key species. We spotted an oceanic white tip shark and a deep water squid. The squid was dead and partially consumed, floating on the water's surface. It was likely brought up from the depths by a deep diving cetacean such as a pilot whale or beaked whale. Sometimes we find these squid by sighing birds sitting on the water, feeding on the squid. But this one was simply floating at the surface and we happened to drive by it in our boat. We pick up the squid with our sample net, place it in a labeled ziploc bag and it will be shipped to Seattle for genetic identification. Notice all the little fish that make floating items like this their home.

A lost squid meal floating at the water's surface with small fishes using it as a temporary home.
Several hours later we spotted the ocean white tip. It also had a large school of fish associated with it (not visible in the picture). In this case, there were larger fish that were below the shark, perhaps feeding small leftovers from the sharks meals.  Both the squid and shark are key links in the ecology of the system here in Hawaii and elsewhere. Squid are a vital link between top predators such as sharks, cetaceans, birds and game fish, and the squids smaller and more abundant pelagic and mesopelagic prey. Sharks are the top of the food chain and sentinel predator species that are often over fished.

Oceanic white tip reef shark.

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