On Climate, Cod, Copepods, and Conjunctions

Scientists found a decline in zooplankton like these Centropages copepods in areas with warming waters.

The warming of New England’s waters due to climate change is affecting the availability of food for larval cod, according to a study by scientists at NOAA’s Northeast Fisheries Science Center.

The scientists looked for overlap among areas affected by three recent phenomena: record high sea surface temperatures, low abundance of zooplankton, and depleted cod populations. They found that some zooplankton that Atlantic cod larvae depend on for food have declined in abundance in response to warming and in the same areas where cod are not doing well.

As NOAA’s press release puts it, this means that changing water temperatures “have profoundly affected” key zooplankton species and “may be influencing the recovery of Atlantic cod and other fish stocks in the region.”

The decline in zooplankton is bad news for larval cod that feed on the tiny creatures. (Both images via NOAA.)

This important study, published in the journal Progress in Oceanography, gives troubling indications that climate change is already disrupting fundamental components of the marine food web off our coast.

This deserves broader attention and should spark further investigation of the effects of global warming on our ocean resources. Climate change is likely exacerbating the already bad situation caused by decades of chronic overfishing of cod and other important groundfish (or bottom dwelling) species and damage to their seafloor habitat. Fisheries managers can’t control the climate, but they should be using the tools they have to give fish a fighting chance to adapt to warming waters.


Fortunately, two upcoming events promise to expand the conversation about climate change and fishing.

On July 23 NOAA holds a one-day workshop “Understanding Climate Impacts on Fish Stocks of the Northeast Shelf Large Marine Ecosystem” at the Omni Hotel in Providence, RI. This event will encourage researchers in oceanography and fisheries sciences to identify needs and priorities for their work.

A week after that the Island Institute is hosting a two-day event (July 31-Aug. 1) called “A Climate of Change: Climate Change and New England Fisheries” in Portland, ME. This event will bring together scientists, fishermen, fisheries managers and NGO members to share observations and ideas about how to manage resources in the face of a changing environment.


Unfortunately, some media coverage of this important science does a great disservice by misrepresenting the results. Apparently, some in the fishing industry want climate change to take the blame for all the damage overfishing has inflicted. Consider these misleading headlines in the Providence Business News and Boston Business Journal:

Scientists: Global warming, not fishing, is killing off the cod

Climate change, not overfishing, affect fish stocks

And the online aggregator Seafood News went with this headline:

Scientists say global warming – specifically change in plankton – doomed New England cod

Sigh. As much as some might want global warming to become the fall guy for fishing, the NOAA science study does not conclude that climate change alone has depleted fish populations, nor does it absolve overfishing of blame. NOAA’s press release accompanying the study clearly states that the effects of warming they’ve identified occur “in the same areas where Atlantic cod stocks have struggled to rebuild after an extended period of overfishing.”

The problem with those business journal headlines above really comes down to just one word: “Not.” A more accurate headline would replace “Not” with “And.” Our fish are challenged by both a future of warmer waters and a legacy of unwise management. (Conjunctions matter, people!)

So for those who want to learn more about climate change and our oceans, check out those exciting events later this month.

As for the editors of the Boston and Providence business journals, check out Schoolhouse Rock, circa 1973, for the episode “Conjunction Junction.” After all, what’s your function?

“Conjunction junction watch that function!”



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