Small fish, huge stakes within the Gulf of Maine

It’s summertime on Stellwagen Financial institution, 50 miles north of Chatham, Massachusetts, within the Atlantic Ocean’s Gulf of Maine. Because the solar rises on this late June day, the financial institution hosts seabirds, a lot of them Nice Shearwaters, and humpback, finback, and minke whales. For all these species, the season is determined by a feast of tiny fish known as sand lance, plentiful within the area at the moment of yr.

Shearwaters wheel above the 50-foot analysis vessel Auk. Alongside, humpback fins and tails break the ocean’s floor. Aboard ship, researchers have a front-row seat to a simultaneous aerial and underwater ballet. Whereas they marvel on the present, additionally they work to maintain tabs on all of the gamers — from large whales to small fish — to trace the well being of their ecosystem at a time of unprecedented ocean warming.

Nice Shearwaters spend most of their lives at sea, crusing over white-capped waves on lengthy, stiff wings or feeding in teams on small fish, typically with different seabirds and whales similar to humpbacks.

“Shearwaters are named for his or her gliding flight, which scales these slim-winged seabirds simply above the wave tops,” writes Nathalie Ward in Stellwagen Financial institution: A Information to the Whales, Sea Birds, and Marine Lifetime of the Stellwagen Financial institution Nationwide Marine Sanctuary. “Tipping back and forth to trim sail, the birds effortlessly journey updrafts between the waves, often skimming low into the wave’s trough, solely to reappear past the following crest.”

As shearwaters coast from swell to swell, a humpback calf twirls up and out of the ocean, pirouettes in a full breach, and sprays glowing water droplets in all compass instructions earlier than slipping beneath the waves.

In 1992, Stellwagen Financial institution grew to become New England’s first, and thus far solely, nationwide marine sanctuary, a wild ocean place not removed from the city world of Boston. It was traditionally vital as a fishing floor. Right this moment, it’s an oasis for marine life from the microscopic to the behemoth.

A decade later, in 2002, Stellwagen was designated an Vital Hen Space (IBA). The IBA program, administered in Massachusetts by Mass Audubon, is a part of BirdLife Worldwide’s work to preserve chook habitat. An IBA gives important habitat to breeding, wintering, and/or migrating birds and helps high-priority species, main concentrations of birds, and distinctive chook habitat or has excessive analysis or instructional worth. Stellwagen Financial institution meets all these standards, says marine biologist David Wiley, analysis coordinator for Stellwagen Financial institution Nationwide Marine Sanctuary.

The Nice Shearwater is likely one of the few chook species that breeds within the Southern Hemisphere and migrates north to its nonbreeding vary within the Northern Hemisphere. From November till April, the seabird is discovered alongside the Patagonian shelf off Argentina and in massive nesting colonies on a number of rocky islands within the South Atlantic, together with Tristan da Cunha. Then, in Could, the shearwaters head north up the coasts of South American and North America. From June by way of November, they are often discovered across the Caribbean and alongside the jap coasts of the U.S., Canada, and Greenland earlier than crossing the ocean and flying south alongside the western coasts of Europe and Africa towards their breeding islands.

The shearwaters use Stellwagen and the Gulf of Maine as feeding grounds principally from July by way of November, though the primary birds arrive in June, and a few linger into December. The species is also reported in low numbers from January by way of April alongside the coasts of Alabama, Florida, the Carolinas, Virginia, and the Bahamas, suggesting that at the least some people don’t fly all the way in which to the South Atlantic every year.

Greater than 40 species of seabird summer time on Stellwagen Financial institution; along with Nice Shearwaters, the financial institution attracts Sooty and Manx Shearwaters, and Wilson’s and Leach’s Storm-Petrels.

“Seabirds are glorious indicators of the well being of the marine ecosystem,” says Wiley. “They permit us to trace modifications within the surroundings over time, from their summer time feeding vary on Stellwagen to their migratory routes to their breeding ranges.”

Humpback whales additionally migrate throughout lengthy distances, as much as 10,000 miles every year. The whales feed in summer time in northern waters similar to Stellwagen, then migrate to tropical or subtropical waters to breed and provides start in winter, once they reside on fats reserves.

 

Catching seabirds

What’s sustaining the financial institution’s summer time guests — avian and cetacean? To seek out out, scientists are monitoring each shearwaters and whales. The reply, it seems, lies in numerous small, silvery sand lance.

Since 2013, Stellwagen scientists and their colleagues have positioned tags on Nice Shearwaters. To catch their quarries, the researchers enlist crew members aboard the Auk, which serves because the mothership of two smaller watercraft, the rigid-hulled inflatable boats (RHIBs) Balena and Luna.

The biologists use Luna to motor to the place shearwaters are foraging (Balena is for whale analysis). Then they entice the birds in shut with minimize fish and squid. As soon as a shearwater comes close to the boat, it’s caught with a long-handled web and in the end fitted with a solar- or battery-powered satellite tv for pc (platform terminal transmitter, or PTT) tag and launched. The birds are usually tagged throughout analysis cruises in June, July, and/or September.

Why examine Nice Shearwaters as a substitute of one other of the numerous seabird species that frequent Stellwagen in summer time? As Wiley, Kevin Powers, a biologist on the marine sanctuary, and colleagues wrote in 2017 within the journal Marine Ecology Progress Sequence: “Within the western North Atlantic, Nice Shearwaters are among the many most plentiful seabirds throughout summer time months, but little is understood about their motion ecology and habitat necessities on this ecosystem.”

Knowledge from PTT tags enable the researchers to watch the shearwaters’ actions. The scientists can evaluate the birds’ flight paths to water temperatures, chlorophyll concentrations, ocean fronts, and different components which may have an effect on the birds’ prey. Whereas the analyses primarily give attention to understanding the shearwaters’ meals supply, the tags have additionally allowed the biologists to trace the birds on their southbound migration.

In celebration of Black Birders Week 2021, for instance, that yr’s class of tagged Nice Shearwaters included a chook named Shuri after a personality within the Black Panther movies. DNA from blood sampled when the chook was tagged confirmed that she was a feminine.

From the day she was tagged, July 14, 2021, by way of January 1, 2022, when her tag failed, Shuri traveled 26,465 miles from Massachusetts coastal waters to the south-central South Atlantic. She was the gap chief within the 2021 shearwater class.

Tagging whales

Shearwaters are however one a part of the Stellwagen Financial institution image. Then there are the whales.

If putting a monitoring tag on a shearwater is not any simple feat, doing the identical on a humpback whale is orders of magnitude more difficult. On a vibrant morning after summer time solstice, the Balena ferries biologists to the middle of a whale pod. There, in an try to repair a tag on a humpback, the researchers hope to nostril as much as a whale whose flank, the place the tag will likely be positioned, is uncovered.

The scientists are utilizing a suction-cup tag known as CATS, for Personalized Animal Monitoring Options. CATS tags carry two video cameras, together with accelerometers, gyroscopes, and sensors to watch temperature, gentle, and different variables. The devices observe the mechanics of whale feeding, in addition to “see” different humpbacks in the identical space because the tagged whale.

Wiley takes the helm of the Balena; the Luna is the chase boat that follows alongside, able to see the place a whale goes instantly after it’s tagged. Instantly, a humpback surfaces close to Balena’s starboard facet. The crew is all-systems go. Wiley guides the boat alongside the whale, whereas staff member Mike Thompson, a researcher at Stellwagen, extends a 40-foot-long pole towards the whale. A CATS tag is mounted on its finish. With luck, Thompson will gently place the tag on the humpback. “Tag on!” he yells because the whale disappears beneath the waves.

“Take a look at this place,” says Wiley as he half-turns from the wheel of the Balena to view a pod of humpbacks with shearwaters hovering overhead. “Seabirds and whales, simply in every single place.”

‘All of it is determined by sand lance’

Stellwagen Financial institution, with its sandy backside and comparatively shallow waters, is prime habitat for the sand lance that maintain the birds and whales. The financial institution’s sand lance, which journey in large faculties reaching the tens of hundreds, supply seabirds and whales high-calorie meals.

At night time, sand lance tunnel into sandy sediments or kind faculties near the seafloor. In the course of the day, the fish typically swim in dense mats alongside the seabed. The place sand lance are discovered within the Gulf of Maine, so, too, are shearwaters and humpbacks. “Shearwaters and different seabirds, whales, just about something searching for a meal right here is feeding on these fish,” says Wiley. “On Stellwagen Financial institution, all of it is determined by sand lance.”

Nice Shearwaters and humpback whales head towards areas the place sand lance are plentiful, in keeping with information Wiley and others revealed in October 2020 within the journal Conservation Science and Observe. “The sturdy co-occurrence between these predators and their sand lance prey means that it’s vital to establish the areas the place sand lance reside,” says Wiley. “Discovering extra details about sand lance habitats could point out different areas the place shearwaters and whales combination.”

Greater than 70 species depend on the tiny fish, reviews Michelle Staudinger of the Northeast Local weather Adaptation Science Heart on the College of Massachusetts Amherst. She and colleagues, together with Wiley, revealed a report in 2020 within the journal Fish and Fisheries that additional paperwork the dependence of myriad species — from Nice Shearwaters to Roseate Terns to Atlantic Puffins, humpback whales to bluefin tuna to Atlantic cod — on sand lance.

To see the place the fish are hiding out, Wiley and crew use a seabed remark system often called the SEABOSS, or SEABed Commentary and Sampling System. This boxy eye-in-the-sea permits the researchers to gather sediment samples and procure movies of sand lance seafloor hangouts, in keeping with Thompson. Sand lance surveys are carried out at 44 stations on or close to Stellwagen Financial institution at numerous instances of the yr, together with a few month earlier than the analysis cruise every June.

Waters warming

If tendencies proceed, shearwaters and humpbacks could quickly want fish finders. Fish communities on Stellwagen Financial institution have modified dramatically, in keeping with marine scientists Peter Auster of the Mystic Aquarium and Christian Conroy of the College of New Haven. A 2019 report they co-authored on Stellwagen Financial institution fish particulars species shifts that started within the early Nineteen Eighties.

These years ushered in a two-decade interval of steadily rising sea-surface temperatures. Waters throughout the northeastern United States continental shelf warmed at a fee thrice the worldwide common. In response, many species within the Gulf of Maine moved to larger, cooler depths. For some species, nevertheless, similar to sand lance, deeper realms could not supply the best habitat. Sand lance depend on sand or tremendous gravel, sediment that makes up a lot of the backside in Stellwagen Financial institution’s shallows however isn’t as widespread in its depths.

“The comparatively minimal variety of sand lance collected in trawl surveys carried out since 2010 could mirror, partly, the outcomes of this squeeze between warming waters and most popular habitat,” state Auster and Conroy.

Certainly, sand lance appear to alter location every year, taking the seabirds and whales with them.

Though the June analysis cruise was scheduled to depart from Provincetown, the sand lance — and seabirds and whales — took up residence off a distinct Cape Cod port, Chatham. To maintain up with the shifting scene, the scientists moved the Auk from its berth in Provincetown to a dock in Chatham. “We could also be all about birds and whales,” says Wiley, “however they’re all about sand lance. So, we take a look at the place sand lance are concentrated.”

Feeding frenzy

To catch sand lance on Stellwagen, humpback whales interact in bubble-netting, a way of feeding on small fish. A number of whales sound, or dive, then exhale collectively underwater. When their bubbles attain the floor, they kind a big ring with seafoam within the heart. The bubble ring turns into a web, trapping numerous sand lance. Seconds later, one whale — then a number of — floor within the ring’s heart, large baleen-lined mouths open, straining the water, or dragging, as marine biologists name it, for sand lance.

Humpbacks launch the bubbles whereas swimming in upward spirals, typically throughout a conduct known as double loops. “Double loops” begin with an ascending spiral to corral fish, then the smack of a fluke on the ocean floor and a second lunge to seize the corralled prey. The whales work in groups of two to 10 or extra, rising on the ocean floor in a boiling cauldron of open mouths and flipping fish.

Ready simply above are Nice Shearwaters and different seabirds, which take the freedom of strolling on the whales as they floor, the higher to cheekily snatch sand lance proper out of the leviathans’ mouths.

Will the buffet of sand lance be sufficient to maintain the seabirds and whales going till they return the next summer time? On Stellwagen Financial institution, the fates of shearwaters, humpbacks, and numerous different seabirds and cetaceans, are intertwined with that of 1 very small fish.

Stellwagen Financial institution Nationwide Marine Sanctuary eBird record

Seabird populations declined 70 p.c all through the fashionable industrial period

This text seems within the Could/June 2023 difficulty of BirdWatching journal.