Monterey Bay Aquarium Research Institute
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Krill swarm

A pod of dolphins, a school of fish, a smack of jellies... Many marine organisms form aggregations. Some swarms contain thousands or even millions or animals. Euphuasiids (krill), like those in the picture above, can create swarms so dense that they turn the surface of the ocean pinkish-red. They are key players in California's coastal ecosystem, providing food for everything from small seabirds to blue whales. This particular swarm contains a mix of Euphausia pacifica and Thysanoessa spinifera, the two most common species of krill found around Monterey Bay. They were attracted to the lights on MBARI's remotely operated vehicle (ROV) Ventana while the ROV was working on research instruments in Monterey Canyon. Some parts of this swarm were so dense that the animals could no longer swim. They simply tumbled through the water, so that the swarm billowed and then collapsed like a cloud of smoke.

Note: This image may not be copied, reprinted, or used without explicit permission from MBARI.

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