Featured Creature

Krill are shrimp-like arthropods that make up a large portion of the zooplankton in many regions of the ocean. Krill are near the base of the oceanic food web feeding on phytoplankton. In turn, enormous swarms of krill feed the largest creatures in the ocean: blue and other baleen whales, sea birds, squid, and fish.

Blue whales, the largest animals that ever lived, eat up to four tons of krill a day to fuel their huge bodies. In fact, krill – about two inches long –make up the majority of their diet. Blue and humpback, and other baleen whales, are filter feeders. They take in huge gulps of seawater dense with krill straining out the water though their baleen and then swallowing their catch.

Imagine a creature with such a radically different body plan that we, bilateral humans, can’t really fathom how they have been so successful. Sea stars, and other echinoderms, move and feed like no other animals. They are animals that followed a different evolutionary path after evolving from the same bilateral ancestors as us.

Many still call sea stars “starfish”, but they certainly aren’t fish. No head, no tail, all arms –sea stars are just that: stars. Based on five-part radial symmetry (though some sea stars have many more arms), key functions are coordinated in the center of their bodies, then passed down the arms. The sea star has no brain, but a nerve ring in its center, like a relay station that coordinates the movement of its arms. This nervous system relays impulses from light, touch and chemical sensors around its body.

Where we at Shape of Life live, we know when anchovies are in the neighborhood because when we go down to the ocean, we’ll see hundreds of diving sea birds, jumping sea lions, and if we’re lucky, humpback whales. They’re all here to feed on massive schools of anchovies close to shore. As they swim through the water with their mouths open, anchovies strain out plant and animal plankton. They then are food to all of the animals we see plus so many more, including larger fish and people. In fact, these small schooling fish (@nine inches long) support a large part of the oceanic food web. Some scientists say anchovies are the most important prey—also called forage fish—in the U.S. Pacific Ocean. 

Cephalopods (octopus, cuttlefish and squid) seem to be flourishing in our changing oceans. Their numbers are increasing worldwide according to a 2016 study. Is the increase in cephalopods a good or bad thing?

We know the oceans are warming. We have evidence that that’s a bad thing. What is of additional concern is the effect of warming temperatures on natural ocean food webs. More cephalopods means more voracious predators eating more prey. All this ‘more’ may be a serious problem.