Everybody’s Fish: Striped Bass on the Move

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Schooling striped bass, also known as rockfish.

iStock/stammphoto

Their impressive annual migrations from estuarine nurseries to summer ocean feeding grounds make striped bass a cultural icon along the Atlantic Coast. But with populations struggling, the fish need many helping hands along the way.   

After spawning in the warming spring waters of the Chesapeake Bay’s tidal rivers, migrating adult striped bass begin a sprint. Most head downstream to the Bay’s mouth, though some sneak through the narrow Chesapeake and Delaware Canal that slices through the top of the Eastern Shore. All have the same basic destination: get to the coast, and from there, head north to New England, a distance roughly 500 nautical miles from the mouth of the Bay.

It is these impressive migrations, undertaken mostly by large striped bass, that have captured imaginations and attention along the Atlantic Coast for generations. They are a big reason people from Maryland to New Jersey to Massachusetts think of stripers as “our fish.” But in fact, striped bass are everybody’s fish. And that’s part of the challenge.

Why Is There Concern About Striped Bass Now?

Since 2019, there has been growing concern that striped bass’s remarkable comeback from the population’s near-decimation in the 1980s could be at risk. Warning signs are flashing. Last year marked five consecutive years of poor striped bass reproduction in the Chesapeake Bay, which produces roughly 70 percent of the coastal population. The number of large female striped bass has also remained persistently lower than management targets, imperiling the species’ long-term prospects.

“All of this comes down to what a large and complex fishery this is,” says Allison Colden, CBF’s Maryland Executive Director and a fisheries expert. “You’re trying to manage tens of millions of people. Across fifteen states.”

On top of that, striped bass are consistently among the largest recreational fisheries in the country. In 2022, recreational anglers on the East Coast harvested 3.4 million striped bass, and caught and released an estimated 29.6 million, according to the Atlantic States Marine Fisheries Commission (ASMFC). The 2022 recreational harvest was 88 percent above levels in 2021, prompting emergency management actions last year to limit the size and number of fish caught. The restrictions were officially adopted into the coastal management plan for striped bass this year.

Historically, the annual move to the ocean had significant benefits for striped bass, including a reprieve from historical intense fishing in the Bay, says Dave Secor, an expert on fish migration and Professor of Fisheries Science at the University of Maryland Center for Environmental Science’s Chesapeake Biological Laboratory.

“They could escape the recreational and commercial fisheries of the 1970s and early 80s by migrating,” he says. “They were caught on the coast, but the fishing pressure was less because it was a much bigger area. That’s no longer the case.”

Together with all of the other likely stressors—including shifting conditions due to climate change, pollution, invasive predators, and disease—the perennial popularity of striped bass as a sportfish is an immense challenge as managers try to rebuild the population by 2029 and ensure its longevity.

“All of this comes down to what a large and complex fishery this is,” says Allison Colden, CBF’s Maryland Executive Director and a fisheries expert. “You’re trying to manage tens of millions of people. Across fifteen states.”

Understanding how, when, and where the fish migrate is an important piece of the management puzzle—leading to insights that could help preserve not only today’s fish, but also the diversity of behaviors that are crucial to the population’s long-term survival in a changing world.

The ‘Moveable Feast’

But why do striped bass migrate in the first place, and why the hurry to reach New England?

In short, they are following the food, says Ben Gahagan, Recreational Fisheries Program Leader at the Massachusetts Division of Marine Fisheries. As waters warm around Cape Cod and in the Gulf of Maine, large blooms of phytoplankton and zooplankton draw masses of schooling forage fish like herring and menhaden, he explains. Striped bass, a top predator, follow and hunt the dense schools, as well as a plethora of other species they can get their mouths around—young rays, lobsters, sand eels, even baby ducks.

Gahagan says an academic advisor of his described the seasonal phenomenon as “a moveable feast,” borrowing the term from the memoir of Ernest Hemingway.  

However, while striped bass are drawn by their prey, they are also following well-worn behavioral paths with an almost uncanny loyalty. Using acoustic telemetry to track tagged fish using arrays of receivers along the coast, researchers including Secor and Gahagan have found that groups of striped bass share the same migration behaviors year after year.

“These fish pick up these migratory routes, and it’s not just, ‘I’m going to come to Massachusetts for the summer.’ It’s, ‘I know this rock pile off Salem. I love this rock pile. I will be here in the second week of July until the first week of August, because I know this is a pretty good place where I won’t get eaten and I’ll have lots of food to eat,” Gahagan says. “The same fish will come back to the same spot within five days every year.”

On the heels of the fish comes another predator, too: humans. A lot of them. Each year, Massachusetts is one of the most popular places for striped bass fishing, its recreational fishery often among the top states on the Atlantic Coast and responsible for around $600 million in economic activity, Gahagan says, based on back-of-the-envelope estimates.

“They’ve always been a cultural touchstone for anglers,” he says. “So what happens to striped bass in Massachusetts during the summer has large implications for the whole stock.”

But it goes both ways. Gahagan’s research looking at the genetics of fish along the Massachusetts coast has confirmed a direct link to populations in the Chesapeake Bay and Delaware River, with anywhere between 60 to 80 percent originating in those areas.  

“As the Chesapeake Bay goes, so goes this coastal fishing,” he says.

The Impact of Different Migration Behaviors on Survival

Not all striped bass migrate. Some, primarily smaller and younger fish, stay in estuaries like the Chesapeake Bay year-round.  

Differences in migration behaviors aren’t just interesting; they have a significant effect on a fish’s survival—and therefore the overall population structure.

“The traditional idea is that as fish become bigger, they become more migratory,” says Secor. “They are capable of feeding on larger prey because they are swimming faster, and they have greater transit distances and periods they can swim.

However, while this general trend still holds true, telemetry and genetics studies are revealing that the striped bass migration behaviors are invariably more complex. For example, new genetic data that Gahagan collected indicate that some smaller fish may be leaving the Bay and making their way to Massachusetts much earlier than would be expected from their size.

Among the fish who do migrate, there is also an astounding diversity in migration behaviors. Secor and his colleagues have studied the behavior of these different ‘contingents’ of fish in both the Chesapeake Bay and the Hudson River.

While there are still a lot of unknowns, the studies found a consistent, and potentially game-changing, theme. Differences in migration behaviors aren’t just interesting; they have a significant effect on a fish’s survival—and therefore the overall population structure.

For example, in a 2020 study of striped bass from the Potomac River, they found that fish that migrated to the ocean had a mortality rate of 36.9 percent per year, while the fish that stayed in the Bay suffered nearly two times that rate—70.3 percent.

In another study published in 2020 about the timing of different spawning runs in the Hudson River, they found that fish in 2017 that spawned in the lower reaches of the river and left earlier had a 57 percent survival rate. Fish that spawned in the upper reaches of the river and left roughly 9 days later, in comparison, had an 82 percent survival rate. They concluded that the early exit likely made the first contingent more vulnerable to heavy coastal fishing pressure, resulting in the higher mortality.

The variation in behaviors is beneficial to the population overall, Secor says.

“Just like in a stock portfolio, you’re balancing risk, because there are outcomes that you can’t predict,” Secor says. “You spread that risk by having different migration behaviors.”

Managing Striped Bass for the Future

All of this has important implications for striped bass management and ensuring the population’s long-term wellbeing in a rapidly changing ocean. What the research points to is that it’s not only important to protect enough striped bass to keep numbers up overall, it is also important to preserve the diversity of behaviors exhibited by different groups of fish.

“They make populations more resilient from what we would expect,” Secor says. “If they were all doing the same things, they would all be caught. Because they do different things, they don’t. And in terms of things like climate change, some minority behaviors may be adaptive in the future as the situation changes.”

Both Secor and Gahagan say there is another possible layer, too. Scientists don’t yet know how striped bass adopt their migration behaviors, but it is likely that they may be learning from other fish. If that is true, then preserving enough fish with knowledge of a specific migration pattern becomes even more important.  

The Impacts of Fishing Harvest

But the popularity and intensity of today’s fisheries can make that challenging.

In 2020, ASMFC found that an update to recreational data collection resulted in an increase in recreational fishing mortality estimates and shifted models of the population’s numbers down to concerning levels, says CBF’s Colden. Subsequent management actions seemed to have things back on track.

 “Everything was looking good, we were on a rebuilding plan, and the numbers from 2021 looked ok,” Colden says. “We actually reduced fishing mortality more than was necessary, and we had a 97 percent chance of rebuilding the population by 2029.”

Then 2022 hit, with numbers showing an 88 percent spike in recreational harvest. ASMFC concluded it was likely due to the arrival of large striped bass that were spawned in 2015. This was one of the last good years for striped bass reproduction, and by 2022 the fish spawned that year were finally big enough for anglers to legally keep.  

“Our probability of rebuilding [the population] by 2029 went from 97 percent to less than 15 percent,” says Colden.

One of the biggest concerns is reducing the number of striped bass that die after being caught and released. Even though it is unintentional, an estimated 9 percent of all fish released alive die from stress or injury. In 2022, ASMFC estimates nearly 2.7 million striped bass met their end this way, accounting for 39 percent of the striped bass that died coastwide from commercial and recreational harvest.

What Anglers Can Do to Help Striped Bass

Anglers, whether fishing in the ocean or in the Bay, can help reduce this number by practicing safe fish handling. That includes things like keeping the fish in the water as much as possible, limiting handling time, handling fish with wetted hands, and using gear that reduces the chance of injury—such as circle hooks and lures with as few hooks as possible. It’s also important to avoid fishing for striped bass in hot weather, which adds to their stress, and anglers should consider targeting other species, says Colden.

To better understand the most important factors for reducing catch-and-release mortality, Gahagan and his colleagues are also conducting a citizen science project asking anglers to submit data about their fishing trips, which is updated weekly on a public website. They are looking for more participants from the Mid-Atlantic region.

The ASMFC also kicked off a special workgroup this summer to examine recreational release mortality in more detail and explore additional options to reduce it. For example, there may be ways to limit or close certain seasons for striped bass to control fishing effort, like extending Maryland’s summer closure to cover the hottest months in July and August, Colden says.

“Once somebody is out there, they’re limited to one fish per person per day, but right now we’re not controlling how many people are out there,” she says. “And that’s because it’s the one thing that is most controversial—it’s people’s access to the resource.”

At the end of the day, striped bass truly are everyone’s fish. And it will take everyone working together to save them.

“This is a fish that joins all of us,” Gahagan says. “And we need to act collectively, or it’s going to be really difficult to have a positive outcome.”

Codi Yeager-90x110

Codi Yeager

Senior Writer, CBF

[email protected]

Issues in this Post

Fisheries   Chesapeake Wildlife   Striped Bass (Rockfish)  




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