When it comes to animals and their behavior, words matter. They can shape public perception and scientific understanding, affecting support for conservation and further research. And there are few animals for which words are more important than those that have been historically maligned, like sharks.

For many, the term “shark” conjures the image of a mindless, man-eating machine, a solitary creature roaming the world’s oceans in search of the one thing that drives it: prey.  Unfortunately, this is largely because of the way these animals have been depicted by the media. Researchers in the Big Fish Lab at Oregon State University (including former Ethogram editor Dr. Alexandra McInturf) are revising the narrative around these critically important species. They aim to demonstrate their complexity and highlight how they respond to many things (not just their next meal). To do so, they are drawing attention not only to the animals themselves, but how we describe them.

In their 2023 publication in ICES Journal of Marine Science, “A unified paradigm for defining elasmobranch aggregations”, Dr. McInturf and her colleagues examine shark behaviors that might be unexpected to those who do not observe these animals regularly. Specifically, they try to determine what it means for sharks to “aggregate”. Across organisms, there are many forms of animals moving, resting, or coordinating behaviors together – grouping, flocking, gathering, shoaling, schooling. Researchers globally have found that many shark species do the same. They can be found together more often than alone, and in some cases seem to coordinate their swimming or feeding behavior with other sharks. To date, most of these events, where the animals are swimming or are present together in some way, have been termed “aggregations”.

For centuries, fishing records and the scientific record alike have noted aggregations of sharks. These descriptions are vitally important because they indicate that sharks possess the capacity to identify and associate with other individuals, much like the behaviors exhibited by primates or birds. However, as the researchers in this study point out, the broad use of the term “aggregation” has inhibited our understanding of how and why these behaviors occur. In general, are two major reasons (or drivers) that determine why animals may come together. The first is because there is something in the environment that is attractive, like prey or a good habitat. The second is because the animals are “social”, which means that they are attracted to other animals. This distinction gives us insight into the purpose of the behavior. Are the animals mating here? Is this a sign of a valuable habitat that might require protection? Are individuals learning from each other about how to eat or where to go? In literature on other species, primarily those in terrestrial (or land-based) environments, there are terms to differentiate these types of formations based on what is driving them-the environment or other animals. However, most descriptions of shark behavior refer simply to “aggregations”, without further insight into what may be bringing the animals together.

The overall goal of this study is to provide a set of terminology that can be applied to sharks and their relatives, which would allow researchers to better understand what may be happening when sharks are present together. The researchers specifically define aggregation as “the co-occurrence of two or more individuals in space and time due to a common driver.” They then offer multiple other definitions that fall under this broad umbrella term, to classify animals as either social (“social groups”) or those that come together due to some environmental feature (“non-social aggregation”).

Ultimately, the researchers note that these clarifications may seem small, but they are non-trivial. Sharks and their relatives are highly threatened worldwide, and many have been overfished or accidentally captured in large numbers because of their tendency to aggregate. Understanding what drives those aggregations is now vital for their protection. It will allow policymakers and managers to predict under what conditions we might expect to observe large numbers of animals, helping to avoid further population declines and highlighting potential areas to protect. Finally, for a group of organisms historically represented by Jaws, developing further research into social behavior is valuable to shifting public perception and encouraging support for shark conservation.

Dr. Alexandra McInturf is an ABGG alumni, former editor of the ethogram, and currently working as a research associate at Oregon State University’s Big Fish Lab.

Reference:

McInturf, A. G., Bowman, J., Schulte, J., Newton, K. C., Vigil, B., Hönig, M. C., Pelletier, S., Cox, N., Lester, O., Cantor, M., & Chapple, T. K. (2023). A unified paradigm for defining elasmobranch aggregations. Ices Journal of Marine Science, 80(6), 1551–1566. https://doi.org/10.1093/icesjms/fsad099

[Edited by Isabelle McDonald]