Conservation

Where there are birds… there are whales?

Silva, Tammy L., et al. “Exploring the Use of Seabirds as a Dynamic Ocean Management Tool to Mitigate Anthropogenic Risk to Large Whales.” Frontiers in Marine Science (2022): 861. https://doi.org/10.3389/fmars.2022.837604

 

With the drastic increase of shipping over the past few years, vessel strikes are becoming more common. A vessel strike is when a ship strikes a marine animal. Vessel strikes are especially concerning for whales because they can impact whales’ ability to find food, cause injury, inhibit movement and even cause death. 

Most marine vessels are required to stay at least 100 meters (300 ft) away from whales in an effort to mitigate vessel strikes. Photo by Ashley Mickens.

While protective measures are in place to prevent vessel strikes, recent findings have shed light on the work that still needs to be done. In order to better protect whales in the Northern Atlantic, researchers conducted a study that looked at the connection between seabirds and whales.

Why Seabirds? 

Seabirds and whales share a special bond; they both love fish. Seabirds are often found at the top of the food web and can also function as indicators of ecosystem health. Seeing seabirds on the surface is a possible sign that whales are also feeding underneath. This is especially the case for humpback and North Atlantic Right whales, which are the baleen whales at the most risk in the Northern Atlantic. 

Researchers wanted to know how often seeing a specific kind of seabird known as great shearwaters coincided with the presence of whales. To do this, they spent five years surveying both the Gulf of Maine and the Stellwagen Bank National Marine Sanctuary near Boston.

A great shearwater flying over the Gulf Stream in North Carolina. From Wikimedia.

The Survey

The team of researchers monitored previously satellite tagged great shearwaters to see how often whales were also in the same area. Both the shearwaters and the whales eat a small fish, known as a sand lance, commonly found throughout the North Atlantic. While some researchers recorded the locations of both tagged shearwaters and whales, others went out to directly observe the presence of whales. Over the course of five years (2013-2018), they built up a data set that recorded the overlap of the shearwaters and whales at monthly and yearly scales.

 

What did they find?

While the presence of shearwaters overlapped with the presence of humpback whales more than 50% of the time, they did not frequently overlap with the presence of North Atlantic Right whales. The authors did note that sometimes satellite tags fall off the birds, which can cause some missing data points. The authors recommend tagging more shearwaters (and other seabirds) to get a more complete picture of how bird and whale presence overlap in the Northern Atlantic. 

Seabirds searching for food in the Strait of Juan de Fuca. Photo by Ashley Mickens.

The main purpose of this study was to expose the places where whales should be protected, but there may be little to no infrastructure in place to do so. Many marine protected areas (MPAs) have boundaries that are based on political, social and economic factors, as well as historical and ecological data, but the authors recommend incorporating more types of ecological research when updating the boundaries of  MPAs. 

 

Moving Forward

One of the most promising ways to incorporate all of these factors is through Dynamic Ocean Management (DOM) strategies, which may create lasting solutions despite the complexity of the issues facing the world’s ocean today. The authors are excited about the possibility of using real-time satellite tracking of both seabirds and whales for developing new DOM tools at regional scales for conservation efforts. 

If you’re curious about current measures to protect whales from vessel strikes, check out Whale Alert and Right Whale Slow Zones.

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