An Ocean Warming: Atlantic Cod and Northern Shrimp Search for Colder Water

Perhaps no other New England species has felt the effects of the Gulf of Maine’s rapid warming like the fabled Gulf of Maine cod. An iconic species since its discovery centuries ago off of New England’s coast, cod profoundly impacted the way our region developed, and has shaped our coastal economies.

Today, however, the state of the species looks much different, with cod stocks in the Gulf of Maine hovering around three percent of what scientists say are sustainable levels. In an attempt to quell the overfishing of cod, restrictions on fishing quotas have been enacted. However, instead of seeing the cod stocks rebound, the numbers have continued to plummet.

There are two reasons for this: First, continued fishing pressure hasn’t allowed for enough of an opportunity for cod populations to recover. The other reason? You guessed it: drastic warming due to climate change.

Cod’s home is no longer the comfort zone

Climate change has led to warming ecosystems all over the world, but the Gulf of Maine is experiencing this warming trend faster than most. Cod, like every species, has a range of temperatures at which they can live comfortably, which in turn makes a range of geographical areas suitable for them. Historically, the Gulf of Maine has been at the southern boundary of their range. But, with Gulf temperatures rising due to climate change, cod are now starting to move north in search of cooler temperatures.

Because of this shift, restrictions on fishing quotas, even if effective on their own, have failed – as they didn’t account for what would happen due to warming waters.

As scientists and fishery managers have begun digesting this information and its implications, they are increasingly calling for something called “ecosystem-based management,” a management principle that considers the environmental factors in play in a given ecosystem. With widespread use, this broader understanding of what’s happening, and why, could provide a brighter outlook for the future of Gulf of Maine cod.

Northern shrimp headed further north

Another Gulf of Maine species, northern shrimp (pandalus borealis), face a similar situation. This small crustacean is an integral part of the Gulf of Maine food web. It’s unique because it is hermaphroditic, meaning the shrimp first mature as males at around two and a half years of age, and then about a year later develop into females. Northern shrimp feed on plankton and benthic invertebrates, and are then prey for several important species of fish, including cod, redfish, and hake.

For decades, the northern shrimp fishery thrived, until a few years ago, when stocks showed massive declines and low levels of shrimp reaching the age when they’re large enough to be fished. Particularly warm water temperatures during what is known as the “ocean heat wave” of 2012 caused stocks in the Gulf of Maine to drop even more dramatically. Although heavy fishing pressure is partly to blame for the driving the stocks down, scientists also point to the shockingly low levels of fishable shrimp. As the northern shrimp’s lifecycle is highly dependent on temperature fluctuations – with colder temperatures producing higher levels of fishable shrimp – the decline can be linked to warmer waters.

Northern shrimp, like cod, have a narrow range of temperatures in which they can thrive and, similarly, the Gulf of Maine is at the southern end of their range.

Long-term fishery closure a warning sign

Since 2013, the northern shrimp fishing seasons have been closed entirely. With ocean temperatures predicted to continue their warming trend and the species’ already vulnerable status, it looks increasingly bleak for the fishery.

Little by little, we are losing cod and shrimp to colder waters, and others soon may follow. It’s clear the Gulf of Maine and its composition is changing. That’s why plans to mitigate climate change must pay close attention to oceans and the warning signs they’re giving. And in the meantime, fishery managers must do everything within their power to ensure that management strategies incorporate the best climate science possible.

 

 

The Climate Change Connection: The Warming Gulf of Maine Needs Protected Areas

“Do what you can, with what you have, where you are.” –President Theodore Roosevelt 

Considering how quickly our planet is warming, and what little is being done to combat it by our national government, this quote has never been more relevant or applicable.

Photo courtesy Brett Seymour/CLF
Photo courtesy Brett Seymour/CLF

Here in New England, our ocean is especially vulnerable to the impacts of climate change – with one study showing that the Gulf of Maine is warming 99% faster than ocean waters elsewhere on the planet. If that’s not alarming enough, we’re also seeing whole populations of species (such as lobster) moving toward colder waters – which could spell disaster for New England’s economy. And, we are just beginning to understand the effects of ocean acidification on our shellfish populations, with much more to learn before we’ll know how to adapt.

But, what gives us hope amidst this dire news is that we New Englanders, whose lives – and livelihoods – are intertwined with a healthy ocean, have long been champions and leaders for its protection.

Conservation Law Foundation has advocated for ocean conservation in New England for decades, from our fight to stop oil and gas drilling on Georges Bank in the 70s, to our work to protect our iconic cod fishery from extinction, to our commitment to the state and regional ocean planning processes. Today, we’re rallying the public to support the protection of two of the Atlantic’s most fragile and vulnerable areas – the Cashes Ledge Area and the New England Coral Canyons and Seamounts. We’re imploring President Obama to create a Marine National Monument, which can give these special places the highest possible level of protection.

You may be thinking – what does any of this have to do with climate change? The answer is this: Conservation and climate change are inherently connected. President Roosevelt, who uttered the words above, understood the importance of conserving such vital places – he knew that some places were just too beautiful, unique, and fragile to be disturbed or exploited, even if resources such as gold, oil, or gas were to be found there. What he couldn’t have known then is something we do know now: Creating fully protected marine areas is a critical step in our defense against climate change.

Studies of protected areas show that the robust ecosystems they contain are better able to withstand the stress of warming temperatures. The complete and relatively pristine habitats at Cashes Ledge and the Coral Canyons and Seamounts should be kept intact ­– so they can continue to be used as an underwater laboratory for marine scientists as we work urgently to identify how climate change is impacting our oceans and how we can best respond.

If and when the day comes that we are able to stop or even reverse global warming, we need to have done the legwork now to prepare. Will species damaged from warmer temperatures recover and thrive again? Will ocean plant life maintain the ability to provide us with the oxygen we need? Will our children ever get to gaze in wonder at a North Atlantic right whale breaching the ocean’s surface?

We can’t solve climate change in a day. We know it will take a comprehensive, long-term effort. But we should do what can be done today – right now, with what we have, in New England to protect our most significant places for our children and grandchildren. We believe a Marine National Monument designation is the first, best course of action for New England’s ocean right now.

 

Baked Cod: The Path Forward in an Era of Climate Change

In recent weeks, we learned more sobering news for New England’s cod population. A paper published in Science detailed how rapidly increasing ocean temperatures are reducing cod’s productivity and impacting – negatively – the long-term rebuilding potential of New England’s iconic groundfish. The paper confirmed both the theoretical predictions associated with climate change and the recent scientific federal, state, and Canadian trawl surveys that reported a record-low number of cod caught in recent months.

To be clear, the Science authors do not conclude that ocean temperature changes associated with climate change have caused the collapse of cod. We have management-approved overfishing of cod to thank for that.

What rising ocean temperatures do seem to be doing, according to the Science paper, is dramatically changing the productivity of the remaining cod stocks. This makes it more difficult for cod to recover from overfishing today than at any other time in history, and perhaps reduces the ultimate recovery potential even if all fishing were halted. Stock assessments conducted without taking these productivity reductions into full account will dramatically overestimate cod populations and, in turn, fishing quotas.

The Science paper is potentially very important, with major implications for fishing limits on cod for decades to come, But stock assessment scientists have warned for years that their recent models were likely overestimating the amount of cod actually in the water – and the corresponding fishing pressure the stock could withstand. Unfortunately, those warnings have fallen on deaf ears at the New England Fishery Management Council.

In fact, the managers at the Council, dominated by fishermen and state fisheries directors with short-term economic agendas, could hardly have done more than they already have to jeopardize Atlantic cod’s future—climate change or not.

Overfishing, a Weakened Gene Pool, and the Loss of Productive Female Fish

As a result of chronic overfishing, New England’s cod population is likely facing what geneticists call a “population bottleneck,” meaning that the diversity of the remaining cod gene pool is now so greatly reduced that the fish that are left are less resilient to environmental stresses like increasing sea temperatures.

Overfishing has also caused the collapse of the age structure of the cod populations by removing almost all of the larger, more reproductive females (also known as the Big, Old, Fat, Fecund Females, or BOFFFS). Scientists have previously warned that losing these old spawners is a problem for cod productivity, but this new research suggests that the potential damage from their elimination may be significantly greater than imagined as a result of poor, climate change–related ecological conditions.

The Science paper hypothesizes that an underlying factor in the productivity decline of cod this past decade was the correlation between extremely warm spikes in ocean temperatures and the drop in zooplankton species that are critical to the survival of larval cod. With fewer zooplankton, fewer cod larvae make it to their first birthday.

The impacts of this zooplankton decline on cod productivity, however, could be exacerbated by the loss of the BOFFFs. Here’s why:

Cod start to spawn at three to four years old, but young females produce significantly fewer and weaker eggs and cod larvae than their older counterparts. Those elder female fish, on the other hand, produce larger, more viable eggs – sometimes exponentially more healthy eggs – over longer periods of time. If the older female cod population had still been plentiful, they might have produced larvae more capable of surviving variations in zooplankton abundance.

Perhaps the continued presence of larger, older, spawning females to the south of New England (where there is no commercial cod fishery) is one of the reasons that the cod fishery in the nearby warm waters off New Jersey is healthier now than it has been in recent history.

The Cod Aren’t Completely Cooked Yet: Four Potential Solutions

Cod have been in trouble since the 1990s, and now climate change is magnifying these troubles. This new reality, however, is not cause for us to throw in the towel. There are actions that our fishery managers can take now that will make a difference.

First, large cod habitat areas have to be closed to fishingpermanently. This is the only way to protect the large females and increase their number. Designating cod refuges such as the Cashes Ledge Closed Area as a marine national monument will remove the temptation for fishery councils – always under pressure to provide access to fish – to reopen them in the future.

Such monuments would also sustain a critical marine laboratory where more of these complex interactions between cod and our changing ocean environment can be studied and understood.

Second, managers need to gain a better understanding of the cod populations south of Cape Cod. While it is well and good to land “monster” female cod on recreational boat trips, those fish may be the key to re-populating Georges Bank. Caution, rather than a free-for-all, is the best course of action until the patterns of movement of those cod populations, as related to ocean temperature increases, are better understood.

Third, as observed in the Science paper, stock assessment models as well as guidance from the Council’s Science and Statistical Committee must start incorporating more ecosystem variables and reflecting a more appropriate level of scientific precaution in the face of the reality of climate change shifts. Enough talk about scientific uncertainty and ecosystem-based fisheries management; action is needed, and science should have the lead in guiding that action.

Finally, the importance of funding data collection and fishery science is evident from this important Science paper, which was supported by private, philanthropic dollars. NOAA should be undertaking this sort of work – but it is not in a position to even provide adequate and timely stock assessments, because limited funding forces the agency to use the existing outdated models.

NOAA’s funding limitations are constraining both collection of the essential field data needed to understand our changing world as well as the analysis of that data into meaningful and appropriate management advice. If Congress can find $33 million to give fishermen for the most recent “groundfish disaster,” it ought to be able to find money to prevent such avoidable disasters in the future.

Ultimately, the Science paper shines some much needed light on our climate change–related fishery issues in New England, but we can’t let it overshadow decades of mismanagement or justify a fatalistic attitude toward cod rebuilding. Steps can and must be taken, and fishery managers are still on the hook for the success or failure of our current and future cod stocks.

Zooplankton: A tiny creature with a big role in the cod crisis

One of the North Atlantic’s smallest ocean critters is making big waves in New England.

Centropages. Photo courtesy NOAA
Centropages. Photo courtesy NOAA

Over the last decade, we’ve seen the collapse of our iconic Atlantic cod fishery due to extreme overfishing. Now, a new study is showing a potentially disastrous link between the effects of climate change and the ailing species’ chance of recovery.

Warming waters are bound to be bad news for a cold water fish, but the problem goes much deeper than that, affecting the entire life cycle of the species. Some of this is due to tiny, microscopic creatures called zooplankton. So what are these little guys, and why are they so important?

Zooplankton is a categorization of a type of ocean organism that includes various species, including Pseudocalanus spp, and Centropages typicus. These two species happen to be the major food source of larval cod in the Gulf of Maine.

Zooplankton, which are usually smaller than 1/10 of an inch, play a major role in the Atlantic’s food web. When there are lots of them, things are pretty good. Young fish prey on them and grow to be healthy, adult fish.

But when there aren’t enough plankton to go around, species like Atlantic cod can suffer. When cod larvae aren’t easily able to find the food they need to grow, fewer of them make it to their first birthday.

And without lots of cod that survive to be at least 4 years old (the age at which females begin spawning), the recovery of the entire stock can stall. The stock needs larger, older, more productive females to thrive in order to have any hope for recovery.

Warming and shifting

But why would the plankton be in such short supply? This is where climate change comes in. According to NOAA, temperature changes can cause the redistribution of plankton communities. In the Gulf of Maine, scientists have found fewer plankton in the same areas where cod populations have been found to be struggling. The shifts in temperature lead to the displacement of a critical food source, making it difficult for young cod to survive.

Larval cod. Photo courtesy NOAA
Larval cod. Photo courtesy NOAA

With the Gulf of Maine is warming faster than 99% of ocean areas, this is an enormously alarming problem. More temperature changes and the shifting of plankton populations could make it even harder for New England cod populations to return to healthy, sustainable levels.

While the cod crisis is the result of many factors – but the loss of tiny zooplankton is a big problem. When considering how to best help cod stocks recover, fishery managers must take into account the effects of climate change, or else risk the total collapse of the species.

Celebrating New England Lobsters on National Lobster Day

Cashes Ledge Lobster
A lobster at Cashes Ledge. Photo courtesy Brett Seymour/CLF

If there’s one thing we can be sure of, it’s that New Englanders love lobster. It’s weaved into our culture and history, and it’s unimaginable to think of New England without this famed summer seafood.

Few know that lobsters were once so plentiful in New England that Native Americans used them as fertilizer for their fields, and as bait for fishing. And before trapping was common, “catching” a lobster meant picking one up along the shoreline!

During World War II, lobster was viewed as a delicacy, so it wasn’t rationed like other food sources. Lobster meat filled a demand for protein-rich sources, and continued to increase in popularity in post-war years, which encouraged more people to join the industry.

Popular ever since, now when most people are asked what comes to mind when they think of New England, seafood – especially lobster – is typically at the top of the list.

An industry under threat

We love our New England lobster, but there’s evidence suggesting they’re in danger of moving away from their longtime home. That’s because lobster is under threat from climate change, the effects of which can already be seen on this particular species.

The Gulf of Maine is warming faster than 99% of ocean areas. Until last winter’s uncharacteristically cold temperatures, the prior few years saw an increase in catchable lobster – as the warmer temperatures cause them to molt early, and they move toward inshore waters after molting. However, continued warming will ultimately encourage the lobsters to move north to find colder waters, where they spend the majority of their time.

This is already happening in southern New England, where the industry is already suffering, seeing lobsters migrating northward.

And we’re still learning about the potential for damage caused by ocean acidification, as well as how lobsters may be affected by an increase in colder than usual New England winters.

As we celebrate one of New England’s iconic species on National Lobster Day, let’s remember that slowing down climate change is an important priority for ensuring that future generations can enjoy not Canadian or Icelandic lobster, but New England lobster. Click here to support Conservation Law Foundation’s efforts on fighting climate change.