Is there an increase in whale deaths due to windfarms?

Question

During a recent speech in North Carolina, Donald Trump blamed offshore wind farms for the rise in whale deaths.

Trump made the remarks about offshore wind’s possible link to the surge in baleen whale deaths along the East Coast during a campaign speech delivered at Sportsman Boats in Summerville, South Carolina, a town in the state’s “lowcountry” that relies heavily on boating for recreational and economic activity. He made the comment after ripping the Biden administration’s efforts to impose low-speed zones in large swaths of coastal Atlantic waters, a policy which advocates say will help protect whales from vessel strikes.

“You have a better chance of getting struck by lightning than hitting a whale with your boat,” Trump said. “There has only been, listen to this, one such whale killed off the coast of South Carolina in the last 50 years, but on the other hand, [Biden-supported] windmills are causing whales to die in numbers never seen before. Nobody does anything about that.”

Daily Caller 25 September 2023

Fox News seems to agree and publishes such, see YouTube 26K views.

I am skeptical about this. For one, the population of whales has increased markedly in recent years (particularly hump-backed whales) due to conservation efforts and legislation; thus, I suggest, more dead whales will turn up than previously.

Is there any statistical evidence to support Donald Trump's assertions ?

Answer 1

NOAA has found no evidence of a link.

NOAA is the National Oceanic and Atmospheric Administration of the US. From their FAQ about wind farms and whales...

At this point, there is no scientific evidence that noise resulting from offshore wind site characterization surveys could potentially cause mortality of whales. There are no known links between recent large whale mortalities and ongoing offshore wind surveys.

We will continue to gather data to help us determine the cause of death for these mortality events. We will also continue to explore how sound, vessel, and other human activities in the marine environment impact whales and other marine mammals.

Lauren Gaches, NOAA Fisheries Public Affairs Director, stated in a press conference on Jan 18, 2023...

Since January 2016, NOAA Fisheries has been monitoring an Unusual Mortality Event for humpback whales with elevated strandings along the entire East Coast. There are currently 178 humpback whales included in the unusual mortality event. Partial or full necropsy examinations were conducted on approximately half of the whales. Of the whales examined, about 40% had evidence of human interaction, either ship strike or entanglement. And to date, no whale mortality has been attributed to offshore wind activities.

She went on to explain how boat strikes are one of the highest risk factors.

We know of several factors that may be driving these interactions. As the humpback whale population has grown, their occurrence in the Mid-Atlantic has increased. These whales may be following their prey - which we're hearing from our partners in the region - are reportedly close to shore this winter. More whales in the water and traveled areas by boats of all sizes increases the risk of vessel strikes.

Answer 2

As of now (September 2023), it appears that NOAA has found no evidence of a link, as indicated by the accepted answer. They have acknowledged that there is an apparent increase in whale mortality of unclear causation.

This is not to say that they have found that there is no link between windfarms and mortality, that is, they have not shown (so far as I can tell) a lack of correlation. I have not found any academic papers discussing this.

Here is some raw data:

• NOAA's discussion of the humpback whale Unusual Mortality Event https://www.fisheries.noaa.gov/national/marine-life-distress/2016-2023-humpback-whale-unusual-mortality-event-along-atlantic-coast

• NOAA's discussion of the right whale Unusual Mortality Event https://www.fisheries.noaa.gov/national/marine-life-distress/2017-2023-north-atlantic-right-whale-unusual-mortality-event

Both of these contain maps with information on all available incidents.

• Wikipedia seems to have an up-to-date list of pending projects: https://en.wikipedia.org/wiki/List_of_offshore_wind_farms_in_the_United_States
• Seems to be sourced from the Bureau of Ocean Energy Management: https://www.boem.gov/renewable-energy/lease-and-grant-information

From here it would be a matter of looking at the time series of the development pipeline and seeing if there is any correlation between that and the increased whale deaths. I have not found anywhere where someone has done this analysis.

Even were a correlation to be found, establishing causation would still have to be established, but while correlation does not imply causation, lack of correlation strongly implies lack of causation, so this seems like the first step.

EDIT 2023-12-12:

A study has been distributed (at some point in early October, after this question was originally answered) by the National Academies which, while not concluding that there is a connection or lack of connection, enumerates several plausible mechanisms of actions to motivate further research into a possible connection.

The conclusions are all of the form "more research is needed" but it seems clear that while we have no direct evidence of a link, we also have no direct evidence that there is not a link, so this remains well within the bounds of speculation.

Answer 3

Offshore windfarms require seismic surveys before they are built.

The RPS Group consultants explain

Generally, the required site investigation surveys [for planning and permitting of an offshore windfarm] include several progressive phases, where the preceding phase informs on the following phase. Typically three subsurface data sets are collected using Sub-Bottom Profiler (SBP), Single Channel Seismic (SCS) and Multichannel Seismic (MCS) methods. This approach hasn't changed much since the 1970s, and it has significant limitations in spatial aerial coverage and resolution. As a result, it does not provide a complete, continuous picture of the shallow subsurface. Having the complete picture is paramount to the interpreter for accurately characterizing the subsurface and identifying potential hazards.

The Center for Biological Diversity is an environmental action group. They report :

Offshore oil and gas exploration uses deafening seismic surveys that generate the loudest human sounds in the ocean, short of those made by explosives. Seismic testing involves blasting the seafloor with high-powered airguns (a kind of powerful horn) every 10 seconds and measuring the echoes with long tubes to map offshore oil and gas reserves. These blasts disturb, injure and kill marine wildlife around the clock for years on end.

[...]

Department of the Interior environmental studies have estimated that seismic proposals under review would cause more than 31 million instances of harm to marine mammals in the Gulf and 13.5 million harmful interactions with marine mammals in the Atlantic, killing or injuring 138,000 dolphins and whales — including nine endangered North Atlantic right whales, whose calving grounds are off Florida's coast.