Scientists examine black sea bass ahead of offshore turbine project

Maryland DNR taps David Secor to study fish's movements, response to construction

Professor David Secor and his team catch and tag black sea bass off the coast of Ocean City to study their movements and understand the potential impact of wind turbine construction.

The Ocean City skyline fades in the distance as David Secor and his team of young scientists push farther out into the Atlantic Ocean on the charter boat Fin Chaser.

The sun beats heavily down on the small team, a mix of graduate students and faculty research assistants, as they ready their equipment for their first task.

Work done behind closed doors in laboratories starts here, in the field, or in this case, on the water. Today's goal: catch black sea bass they can track using transmitters.

David Secor and Caroline Wiernicki, faculty research assistant, monitor the status of an acoustic receiver the team just placed in the ocean.

Secor, a fisheries expert and professor with University of Maryland Center for Environmental Science’s Chesapeake Biological Laboratory, is studying the movements of the relatively sedentary fish to understand how they respond to disturbances ahead of the state's plan to build a series of wind turbines off its shore.

The project would help Maryland in meeting its commitment to get 20 percent of the state’s electricity from renewable sources by 2022. Construction, however, may potentially be disruptive for the fish and marine life that visit that 94 square nautical mile stretch (79,706 acres) about 10 to 30 miles off Ocean City.

The turbine project calls for the construction of 77 turbines, collectively generating 368 megawatts, according to the Maryland Public Service Commission.

Secor is preparing to measure how black sea bass will respond to construction of a meteorological tower to be located at the center of the site of proposed offshore turbine project. That singular construction effort will offer clues to how the fish may respond to the much larger turbine project that comes later.

With no construction yet, Secor's first hint of an impact actually came from a tropical storm that hit the region last summer.

“It caused most of the black sea bass to evacuate, it was that big of a disturbance,” Secor said.

His experimental method includes tracking the fish at varying distances from where the meteorological tower is proposed. The control site, where Secor and his team were working most recently, is the farthest he’s been from where pile driving will happen.

“Our prediction is the seabass here aren’t going to be moving around very much as they’re putting in that tower, but the ones closer in will.”

When the scientists go fishing, it’s no ordinary fishing trip.

As long as those fish stay within say a square mile or so, they’ll keep chirping away with their little beacons and we’ll keep hearing them, but if they’re somehow disturbed, we expect them all to evacuate. How long they evacuate will tell us how big that disturbance is.

David Secor
Fisheries scientist, Chesapeake Biological Laboratory

Before any line is cast on this six-hour venture, the crew would throw six 45-pound weights overboard. Two weights each are tied to three total acoustic receivers used to create a triangular boundary.

Mike O'Brien carefully inserts a battery-powered transmitter in a fish his team caught.

The fish they catch will be fitted with a battery-powered transmitter that will act like an EZ Pass to the acoustic receivers. If a fish with a transmitter comes within 600 to 800 meters of a receiver, the receiver will log the time and date when it notices the fish, and also measure noise and temperature. That data will be archived until the receiver is retrieved several months later.

“As long as those fish stay within say a square mile or so, they’ll keep chirping away with their little beacons and we’ll keep hearing them, but if they’re somehow disturbed, we expect them all to evacuate. How long they evacuate will tell us how big that disturbance is,” Secor said.

Once the boundary is set, it’s time to fish. Secor commissioned Capt. Dan Stauffer to get them to just the right spots to catch only black sea bass. Stauffer positions the boat above the bow section of the wrecked African Queen and pulls out four fishing poles—three to pull fish from the water and one to put them back.

A special tool added to a fishing line enables the scientists to return the fish back to the depths after receiving a transmitter.

Secor, his graduate student Ellie Rothermel, and Reed Brodnik, a graduate student under Tom Miller who volunteered to help with this trip, work on the first catches of the day, while Mike O’Brien and Caroline Wiernicki, Secor’s faculty research assistants, prepare for the next step.

As fish are brought on board, O’Brien handles the surgery on the fish and Wiernicki takes notes about each fish’s weight, length, sex, and even the time spent on the vessel.

The operating table on which O’Brien works is a cooler filled with a mix of ocean water and a solution that temporarily anesthetizes the fish. He sets a fish one at a time on a halved PVC pipe lined with foam that balances on Velcro straps wrapped around the cooler. Then he makes an incision to place the small transmitter.

When finished, he sews the fish up and sets it aside to fully recover in another cooler that is also serving as a waiting area when fish are caught quickly.The work is a routine and the team works almost on autopilot. The week before, they had another trip with the same goal. Between the two trips, they caught and released more than 40 fish.

Ellie Rothermel works on her fishing pole with hopes of reeling in another fish.

With every fish comes a piece of a larger story that O’Brien can’t wait to read.

“Getting a chance to come out here and do something to make the patterns of where they are, when they’re there, why they’re there just a little bit clearer to myself or someone else is what excites me a little bit about it,” he said.

Among those along for the ride is Secor’s newest student, who despite having started with the group two months prior had already been part of multiple studies with her new team.

With a lifelong appreciation for the sea and its creatures (her first word was “fish”), Rothermel was thrilled to join the project.

“This is a direct way that I can play a part in helping to preserve an animal I really care about and really cared about for a long time,” she said. “And it’s also fun because I get to handle them, actually fish for them, do the surgery and let them go again and know that I’m making a difference in helping to protect something that is important to me.”

The Maryland Department of Natural Resources hired Secor to study the black bass. It is one of several projects in which UMCES scientists are involved related to the offshore wind power.

Helen Bailey, an associate research professor from Chesapeake Biological Laboratory, is investigating on how turbines could impact marine mammals such as porpoises, whales and dolphins. In a recent study, her group found harbor porpoises visit the area more frequently during January to May than previously thought and forage for food significantly more often in the evenings than morning.

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“It is critical to understand where marine mammals spend their time in areas of planning developments, like offshore wind farms, in order to inform regulators and developers on how to most effectively avoid and minimize negative impacts during the construction phase when loud sounds may be emitted,” Bailey said.

Caroline Wiernicki readies to return a black sea bass to the water.

Noise and vibration from construction, including increased boat activity as well as pile-driving, could be damaging to fish and other marine species, and lead to injuries or encourage temporary or long-term departures of fish from the area. That could hurt fishermen and charter boats like the Fin Chaser, Secor said.

If the completed turbines act as artificial reefs, however, that could provide habitat for barnacles, sponges and other invertebrates that could increase fish abundance. That has been the case for oil rigs left in place after they are retired from service, Secor said.

Scientists have also examined the impact of turbines on birds and bats, which risk death from direct collisions with the rotors and can face disruptions to migration routes. Below the surface, installation of undersea cables that get the energy produced to shore can impact the seabed and sediments, which in turn affects the abundance and diversity of benthic organisms.

Examining the project from multiple angles is the best way to answer some of the questions about impact, and when it calls for a day on the water, it can be the best part of the job for a scientist, but not just for the obvious reason.

“There’s something to be said about getting outside and getting to work hands on with the animal you’re studying. It’s amazing and one of the reasons why I love the job, but also there’s something to be said about just the value, the perspective, and the experience itself,” Wiernicki said.

“Just going out today, you get familiar with the resource, you get familiar with the place, you start to ask questions and think of things in a way you don’t normally get in the lab or strictly on paper," she later added. "I think it’s an incredible experience, and I think it’s a really critical part when you’re looking at things like environmental impact of construction or fisheries management.”

What fish would hear

This is what underwater pile-driving would sound like from 500 meters, or about nine football fields away.


This is what it would sound like from more than 18 miles away (35 km) away.