Saving Seafood

Copepods: Cows of the Sea

October 6, 2017 — If you look very closely at a glassful of water from a bay or the ocean, you would probably be surprised by the life inside. You might see miniature crustaceans the size of the period at the end of this sentence or baby crabs and fish that spend only a short span of their lives this small. These creatures are zooplankton, aquatic animals that drift with the currents.

It’s the Little Things 

These tiny animals form the basis of the food web of estuaries, coastal waters, and oceans. Zooplankton feed on microscopic plant-like organisms called phytoplankton, which get their energy from the sun. Tiny crustacean zooplankton called “copepods” are like cows of the sea, eating the phytoplankton and converting the sun’s energy into food for higher trophic levels in the food web. Copepods are some of the most abundant animals on the planet.

Fish such as anchovies cruise through the water with their mouths wide open, filtering copepods and other zooplankton from the water. Anchovies and other planktivores (plankton-eaters) are prey for bigger animals, like tuna, sharks, marine mammals, and seabirds.

Read the full story at NOAA Fisheries GARFO

CLARKE: In hot water

May 19, 2017 — As the president claims that climate change is a “Chinese hoax” and members of Congress deny that it even exists, those of us who live by the sea can testify firsthand to its impacts. They include bigger storms, accelerated sea-level rise and warmer waters. In America’s first seaport, those are game changers to our way of life. They affect our community’s character, soul and livelihood, especially in the commercial fishery.

The biggest long-term threat to fishing in the northwest Atlantic is not excessive regulations, national marine monuments, or overfishing — it’s hot water. Cold water species like cod, and even lobsters and northern shrimp, have to put up with living conditions so uncomfortable that they may be leaving home and heading north.

A recent issue of the journal “Science” shows that over the last 10 years, temperatures in our front yard, the Gulf of Maine, have increased three times faster than almost all of the earth’s oceans. Gulf surface temperatures increased four degrees between 2005 and 2013 and scientists tell us they could go even higher. That spells disaster for the Gulf’s ecosystem.

The world’s oceans absorb most of the heat humans produce, but when we deposit too much heat into the atmosphere and adjacent waters below, sea life pays the price. With nature out of balance, fisheries shift, oceans acidify, and life-sustaining oxygen levels decrease.

Especially alarming is what we are seeing at the lower levels of the food chain. As water temperatures spike, copepods are disappearing. These tiny plankton-like crustaceans anchor the Gulf’s food chain and when they leave, the chain starts to unravel from the bottom up and fish productivity suffers.

Read the full story at The Gloucester Times