Examples of seabirds. (a–c) Cormorants diving, swimming to the surface, and presumably foraging in the vicinity of the AMP. (d-f) Pigeon guillemots swimming, picking at the rotor, and interacting with the AMP. Credit: Cotter et al., 2026, PLOS One, CC-BY 4.0 (creativecommons.org/licenses/by/4.0/)

Tidal turbines harbor the potential to provide a natural, inexhaustible source of power, but have faced some regulatory hurdles and scientific uncertainty about risks to marine life.

A new observational study, published in PLOS One, offers some insight to help quell concerns about the potential risks to marine life. The study, based on observations off the coast of Washington State, shows that there may not be much to worry about when it comes to animals interacting with tidal turbines.

Avoid and evade

To see how animals interacted with tidal turbines, the research team deployed a 1 m² cross-flow tidal turbine in Sequim Bay, WA. They then set up optical and acoustic cameras, along with other sensors, to monitor animal activity. The equipment was in the location for a total of 141 days, but data was analyzed for 109 days of turbine operation. Data collection strategies included scheduled and model-triggered recordings, with human review and machine learning used for animal detection.

Credit: The Wildlife Society

In total, the team recorded 1,044 observations of fish, fish schools, seabirds and harbor seals in the vicinity of the turbine. Although harbor seals and various seabirds were detected many times, the team observed no collisions of either with the turbine. Instead, seals seemed to easily evade or avoid contact with the turbine.

The study authors write, "Three types of seal behavior were observed while the turbine was rotating. In three events, the seal was observed in the background, and did not approach the moving turbine. In four events, the seal approached the moving turbine rotor and swam in its wake with its head oriented towards the turbine before swimming away.

"These interactions ranged in duration from a few seconds to several minutes. Lastly, in two events, the seal was pursuing fish prey. In one of these events, upon encountering the turbine, the seal stopped pursuing the fish and changed trajectory to avoid colliding with the moving turbine rotor (i.e., evasion)."

Seabirds, which often dive into the water to catch fish, were found to largely avoid the turbines. The researchers say birds were only observed when the turbine was not operating and only during the day.

Observations of fish were a bit more difficult to interpret at times, due to small fish being hard to detect. Still, the team identified 229 events containing individual fish encountering the turbine while it was rotating. Out of these, there were four collisions. Three of these appeared to be unharmed and swam away, while the other floated downward, likely indicating that it suffered fatal injuries.

The team says that, in 50 events (or 21.7%), fish exhibited behavior consistent with evasion, such as a change in direction when swimming near the turbine.

Schools of fish, on the other hand, fared better. The study authors explain, "The five schools observed during turbine rotation were composed of unidentified small fish. In all five cases, the fish that encountered the turbine rotor effectively evaded it by swimming upstream and away from the rotor, ultimately passing between cameras and the turbine, or by diving down below the rotor."

Not out of the water yet

The results of the study are promising and consistent with prior similar studies, which also found that many fish and marine mammals avoid operating turbines. However, there were a number of limitations, particularly involving fish.

The researchers say their detection models did not reliably identify small fish, likely undercounting fish encounters. This may mean that a much larger percentage of fish evaded the turbine.

Nighttime sampling was also limited, due to a lack of light and concern that artificial light might influence animal behavior. Because of this, the team relied on occasional strobe lighting at night, and many nocturnal interactions may have been missed.

Observations were also limited to what could be seen within the camera view, so broader avoidance behavior was not captured. In the future, improved machine learning models and sensor placement could enhance detection, especially for small fish and at night.

The size of the turbine in this study is also small compared to others, and results here may not generalize to larger turbines or to different locations with differing marine species.

Further studies are still needed at larger scales and with different turbine designs. Still, the study authors say this is the most comprehensive set of observations of seabird interactions with a tidal turbine to date and brings valuable insight to the discussion of tidal turbine use.

Written for you by our author Krystal Kasal, edited by Sadie Harley, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You’ll get an ad-free account as a thank-you.

Publication details

Emma Cotter et al, Observations of marine animal interactions with a small tidal turbine, PLOS One (2026). DOI: 10.1371/journal.pone.0338376

© 2026 Science X Network

Citation: Marine wildlife rarely interact with tidal turbines—and usually avoid collisions when they do, observations show (2026, January 19) retrieved 19 January 2026 from https://phys.org/news/2026-01-marine-wildlife-rarely-interact-tidal.html

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