Legislators, the scientific community, and animal protection organizations have recently taken an increased interest in the welfare of crustaceans. In response, this study examines some scientific issues and studies related to the topic.

In 2005, the European Food Safety Authority’s Panel on Animal Health and Welfare issued an opinion concluding that at least some crustaceans have complex behaviors and pain systems, indicating that they should receive welfare protections. In March of 2018, Switzerland did just that, including lobsters and crayfish in new welfare legislation. However, the intervening years saw significant pushback from the scientific community regarding crustaceans’ ability to experience pain.

This article examines some scientific studies and issues related to crustacean welfare, and expresses skepticism that crustaceans experience pain similarly to humans. Still, the author is careful to note that the article’s intent is not to advocate for indiscriminate use or abuse of crustaceans.

As a starting point, the author notes that “pain” is typically defined in relation to human experiences or psychological states, so the application of the term to crustaceans may be an anthropomorphization. Additionally, a previous attempt to develop a set of criteria to gauge whether an animal can feel pain defined those criteria broadly. For example, the criteria include minimum anatomical requirements that are vague: the animal must have central processing in a brain, but it is not clear how developed the brain needs to be to imply a capacity for pain. The breadth means that some robots actually meet the criteria for feeling pain, which suggests that the criteria may not be appropriate or accurate.

Regarding the existing body of scientific literature on crustacean welfare, the author identifies a number of general issues:

Much of the research has been poorly conducted: it is not replicated or properly controlled, and interpretations of results are questionable or contradictory. Furthermore, the studies are dubious in design, and are conducted on a very small number of animals, hurting the statistical significance of the results.

It is not clear or proven that certain behaviors are nociception (nervous system response to harmful stimuli) rather than another type of reaction, or that nociception equates to pain.

It is difficult to determine whether a reaction is a normal stress/startle response or a pain response. For example, in studies attempting to assess pain responses to chemicals, stress indicators were the same as when the crabs were simply handled, making it hard to determine whether they were in pain.

There are competing interpretations of similar behaviors in different studies; for example, “escape” behavior could actually be feeding behavior or vice versa.

The scientific literature on these issues is “limited and immature.”

The article’s author acknowledges that there is clear and strong documentation of stress responses in crustaceans, but is not willing to say that stress responses indicate pain or the capacity for pain. In the end, the paper leaves us with six conclusions:

First, design and interpretation flaws in crustacean pain studies set the bar for pain and sentience too low to be meaningful, because they often take a “benefit of the doubt” approach that broadly assumes pain is being experienced when there is little to no evidence one way or the other.

Second, the present situation of advocating for stringent welfare protections for crustaceans may mean that scientific research is being needlessly restricted.

Third, most existing crustacean welfare studies are guilty of non-replicable results and over-interpretation of certain behaviors. More biologically plausible explanations of these behaviors are often ignored.

Fourth, the author simply feels that it doesn’t seem like crustaceans need to be included in animal welfare legislation at this time.

Fifth, restrictive welfare legislation may create a situation where you cannot conduct the research necessary to answer open scientific questions about the welfare of crustaceans. Indeed, once an animal species is added to welfare legislation, it’s typically difficult to remove. As such, the author believes it might be appropriate to add “sunset clauses” or other safeguards when including certain animals in welfare regulation, so that it’s possible to adjust the legislation expediently based on future research.

Finally, though, the author reiterates that crustaceans should not be used or abused indiscriminately. That said, the author feels regulatory decisions should be made on the basis of extremely high-quality research, and that the existing research on the subject is not of such a quality to drive welfare legislation at this time.

And so it seems that, when it comes to the scientific community, the jury is still out on the subject of crustacean welfare, and the paper highlights just how much we don’t know about crustacean lives in general. Unfortunately, many of the conclusions this author provides would mean that crustaceans are needlessly subjected to animal cruelty in laboratories or other places of research, all in the name of finding out whether they feel pain or not. This may be a case where the precautionary principle is an ideal fit.

Animal advocates and animal protection groups interested in promoting crustacean welfare may want to take note of the concerns raised in this article, and aim to address them in future research and advocacy work.