More than 500 whales were stranded on the East Coast between 1995 and 2022. Many of those were discovered in our region.
WSHU’s Sabrina Garone spoke with Dr. Lesley Thorne of Stony Brook University’s School of Marine and Atmospheric Sciences. Thorne led a study that looked into the possible explanations.
WSHU: Of those hundreds of strandings, most of those happened between 2016 and 2022. Your study took a look at some of the reasons for this. Could you take me through the major findings?
LT: We looked at patterns of large whale strandings relative to that of different threats to large whales. And we focused on humpback whales, which are the species that strand most frequently on the East Coast. Vessel strikes, where whales are struck and hurt by vessels, and entanglement in fishing gear are major threats that face whales globally. So, we looked at patterns of vessel traffic and fishing efforts.
And we also looked at activities occurring along the U.S. East Coast associated with offshore wind development. And what we found was that mortalities and serious injuries due to vessel strikes increased threefold during this time period post-2016. We did not find any evidence that offshore wind development, or site assessment surveys for offshore wind development, played a role in the increase in whale strandings. In short, our analysis suggested that vessel strikes were an important driver, and that vessel strikes were exacerbated by increases in traffic in key regions. As well as key changes in humpback whale habitat use and distribution.
WSHU: I remember last year, I feel like we were reporting on whales turning up on Long Island beachesall the time. Please correct me on the number, but I want to say it was like over 30 in a year. What is it about the waters around our region that they've become such a hot spot for whale strandings?
LT: That's exactly what we saw, that waters in New York and also Virginia were a hot spot for strandings, and also for mortalities that were deemed to vessel strikes specifically. There are a few things going on here. Firstly, there is very high vessel traffic in New York. In fact in 2022, New York and New Jersey became the busiest ports in the U.S. Humpbacks have been observed foraging regularly in the waters of New York and New Jersey since about 2011. And that regular use of foraging habitat, likely represents an expansion of whales into other foraging habitats, as the abundance of humpbacks in the Gulf of Maine has increased.
In addition, there have been changes to the prey species that the whales are feeding on. Atlantic menhaden are a fatty, energy-rich fish species that humpback whales frequently feed on in inshore waters of New York. And the increase in strandings near mid-Atlantic states has corresponded with the increase in the spawning stockpile mass of menhaden. Menhaden were previously overfished, but their abundance in mid-Atlantic states began to increase in the mid-2010s. One last factor is the prevalence of juvenile whales. They may be more susceptible to threats like vessel strikes due to a lack of experience.
WSHU: I think a conclusion that a lot of the general public is jumping to is offshore wind because that kind of development is pretty new to our region. And it kind of lines up with the timeline in that spike in whale deaths, but you say there's really no concrete evidence of that. Can you speak to that a little bit more?
LT: So, we looked at potential threats of different phases of offshore wind development, and in short, we found no evidence that offshore wind development is related to these patterns. I think there are a few important things to point out here. The first is that while there is a great deal of offshore wind construction that is planned for the coming years, there's actually been very little to date. So, the construction of offshore wind farms may threaten humpback whales and other marine mammal species, primarily due to the noise associated with pile driving.
However, our study focused on strandings through 2022. And at that time, there were actually only seven wind turbines that had been constructed — five off of Block Island in Rhode Island, and two off of Virginia. While there was little construction or operation of wind turbines during the time we looked at through 2022, there have been survey efforts to assess and characterize potential wind lease areas. For the surveys to take place, there are authorizations that are required, and they are publicly reported. So as part of the study, we looked at when and where these site authorizations took place relative to when and where humpback whale strandings occurred. Our assessment of these spatiotemporal patterns did not suggest a link. In fact, the elevated number of humpback whale strandings pre-dated the survey authorizations.
WSHU: Are there any success stories that we can celebrate when it comes to whales and other marine mammals in our region? I feel like the last few summers, Long Islanders have seen a lot more sharks, a lot more dolphins. At least in my experience, my town beach in Nassau, we see dolphins all the time now. Is this a good sign that some species are on the rebound, or are they showing up in different areas because of changes in their usual spots or their diet?
LT: The humpback whale population in the mid-Atlantic is increasing and has been increasing in recent decades. And on some level, that's involved here because we're seeing this expansion into new habitat areas, so that is obviously a positive thing, as this population is increasing.
WSHU: It's cool to see them too, which leads me to my next question. With summer here and a lot more people getting out on the water, hanging out on the beach, what kinds of whale species and other marine mammals are common this time of year that we can keep an eye out for? Are there any specific locations on the island you recommend people check out if they want to spot wildlife?
LT: Humpback whales are very common, and particularly in near inshore waters. There are also a lot of fin whales, which are an endangered species, although that's occurring in waters a bit further offshore. We also frequently see bottlenose dolphins and common dolphins in near-shore waters. And in terms of where, anywhere along the south shore of Long Island, you can see a lot of cool marine life and marine mega-fauna right close to shore!
In fact, humpback whales are often feeding on these surface menhaden schools in very shallow waters right near the beach. And you don't necessarily need to be on a boat. For example, I was camping on Fire Island last weekend, and we were watching humpback whales breach just off the beach from land!
