Are all tunas fish? If fish are cold-blooded vertebrates that have fins instead of legs, breath in water, and live in water, then, no, not all tunas are fish. In fact, we have known for nearly fifty years that some tunas, technically, do not fit the common ichthyic classification (Carey and Lawson 1973; Harding et al. 2021). The reason is that some tunas, for example Atlantic bluefin tuna, have the ability to regulate aspects of their own body temperature. In other words, these tunas are warm-blooded. And if fish are, by definition, cold-blooded, then these tunas are not fish.
In this Ocean Nexus blog post I will use ideas from environmental sociology and the philosophy of science to argue that this classificatory quirk and others like it are actually quite consequential. There is a lot to be gained by paying attention to the ways in which we classify the world around us, scientifically or otherwise. For not only does classification influence the ways we think about nature and our place in it, but, I will argue, classification also has an immense influence on the ways human beings physically interact with nature. In addition, there are always a whole lot of political, cultural, and scientific histories tied up in the process of classification that are usually worthy of our attention. If we want to rethink aspects of our research in order to advance equitable outcomes in human-marine systems, part of this rethinking should start with questioning our systems of classification.
A key source with which to begin this rethinking is likely John Dupré’s 1999 essay, “Are Whales Fish?” from which the theme (and title) of this blog post derives. As our tuna example above has already demonstrated, the answer to Dupré’s question is more complicated than it might seem. It is complicated especially because classification schemata change drastically across human populations and over time.
Consider Herman Melville’s 1851 novel “Moby Dick: or, The Whale,” perhaps the most famous work of fiction set largely on the ocean. Melville’s novel is noted not only for its bare picture of our insatiable thirst for meaning in a world saturated by duplicity and delusion but also for its accurate depiction of 19th century whaling, where characters refer to whales as “fish.” For instance, whalers aboard Ahab’s boat “the Pequod” separate whales into two categories. There are “fast-fish,” or whales that have been marked by a ships’ crew and thus must be left alone by other whalers, and “loose-fish,” or whales that are up for grabs. Indeed, few doubt that whalers of this era referred to whales as fish.
So, when did whales become mammals? Actually, according to western natural science, they had been classified as such over fifty years before Melville began composing Moby Dick (Burnett 2012; York 2017). So what accounts for these different classificatory schemata? While Dupré does not discuss Moby Dick, I imagine he would simply point out that “scientific” language and “ordinary” or “folk” language usually provide independent ways of classifying and organizing nature, and both often work quite well for the purposes to which they are put. In other words, the point is not that folk language is wrong and scientific language is right, or vice versa, but rather that folk language is usually a very successful tool for the people that use it. It is simply different than scientific language and has different uses. For example, as opposed to scientific language, folk language usually focuses on the level above the species (the bird, for example, as opposed to the White-winged or White-rumped swallow), and is only used according to the times and spaces in which a particular culture resides.
Does this mean that whales are, indeed, fish, or that tuna are not fish? Not exactly. Over the century and half since Moby Dick was published, scientific language about whales has overtaken folk language in common parlance, and waging lexicographic war to render whales’ fish (or tuna as merely fish-adjacent) is not worth any fight. The point rather is that scientists did not “discover” what is a fish or a mammal via some objective clues provided by nature, they instead “decided” what is a fish or a mammal provided past knowledge and the new empirical clues gleaned from their increasingly sophisticated tools.
There are many ways of successfully classifying the natural world. Though, we must admit, that in specific contexts some ways of doing so are better than others. The use of a particular classification scheme is dependent upon ones’ goals. If our present goal is fine-grained natural science, I would stick with accepted forms of scientific classification. Though if I were on a mid-19th century whaling boat, there is a whole host of reasons why I wouldn’t challenge anyone who called the whales we were after “fish.”
As these examples show, systems of classification are certainly useful, but are always social choices that could be different. Moreover, classification is rarely consistent in some absolute sense.
So, who cares? We should care because, for all of us, our classification schemes help to define our methods of knowledge production, and this process can have direct political and material implications.
For example, if we are serious about equitable outcomes for all, then our stewardship of the oceans must be able to handle multiple systems of knowledge production. While, at this point in history, there are few peoples who have not interacted with western forms of knowledge, many have retained some aspects of traditional knowledge or have combined localized “folk” knowledge with western knowledge into something novel. These non- or partially western systems of knowledge production are not necessarily wrong, though nor are they necessarily correct. They may simply adhere to different classificatory systems. And our science and politics should remain open to the idea that, in part or in whole, these systems may work better for local ocean stewardship than western methods.
In addition, scientific classification schemata can have immediate material implications. For instance, classifying a specific species as an “invasive” threat to a valued marine ecosystem can have direct material implications (Besek 2019). Mitigation efforts may be taken in order to stop the migration of that species, eliminate much of its population, or destroy aspects of its habitat that otherwise would not have occurred had that classificatory label not been put in place. The “invasive” label then not only classifies knowledge in a new way, but physically organizes social interaction with that species. This is why the American Bird Conservatory has advocacy campaigns to label cats as invasive. Such a classification would not only reorganize our relationship with a popular house pet, but, also, according to the American Bird Conservatory, save the lives of around 1 billion birds per year and reverse the recent declines of birds like the Least Tern and Wood Thrush (American Bird Conservancy 2022). Similarly, deeming a particular marine system as “polluted” (Shtob and Besek 2019), worth “conserving” (Morar, Toadvine, and Bohannan 2015), or a population of living beings a distinct “species” at all (Scoville 2019), can have an immense material influence on the ways we politically and physically interact with nature.
I am not arguing that these classificatory labels are false, or mere “social constructions,” but whether or not to call a species “invasive,” “endangered,” or a “species” at all are not innocent, objective choices. They are choices that are political as well as scientific, and they can have an enormous effect on human and nonhuman life.
I want to conclude by claiming that I hope this blog post is understood as a defense of scientific classification, just not a defense of determinist classification. Scientific classifications are not provided by nature, but are choices we make for specific reasons. If we pay more attention to these choices, we can then begin to ask some bigger questions. For instance, why do we often classify and organize bodies of water according to market principles as opposed to conservationist principles (Lave and Doyle 2021)? What are the differences between legal systems of classification and scientific systems, and how might they better align (Shtob and Besek 2021)?
In all, how can we better define our scientific goals, and how can our classification schemata change in order to better accomplish these goals? This is a much longer discussion for another time, though I would argue that, whatever its outcomes, I, myself, am going to continue referring to tuna as a type of “fish.”