Guidelines for protecting and promoting decapod crustacean welfare in research

The decapod order contains ~15,000 species, including crabs, lobsters, crayfish, prawns, and shrimps. The idea that these animals might experience pain was long dismissed because they were thought to respond to noxious stimuli and tissue damage purely by nociceptive reflex—a position questioned by Sherwin (2001). Later experimental studies demonstrated that their responses were complex, long-lasting, and largely consistent with criteria for pain that had been produced initially for vertebrates (Elwood 2019). While the nature and extent of potential sentience in decapods remains an active area of research, these animals were recently recognized as sentient for the purposes of UK law, suggesting that the evidence for this conclusion is far from negligible (Crump et al. 2022).
The present guidelines were developed at the behest of the leadership of the Insect Welfare Research Society (IWRS) and modified from Fischer et al.’s (2023) guidelines on insect welfare in research. They are intended to help individuals studying decapod crustaceans in laboratory, field, education, and industry contexts. The guidelines are informed by standard principles of research animal care and use: the 3Rs (Russell and Burch 1959). The 3Rs encourage researchers
to replace animals with non-animal models, reduce the number of animals used in research, and refine research, housing, and husbandry methods to minimize stress. Given these principles, the guidelines provide strategies for protecting and promoting decapod crustacean welfare.
Replacement is motivated by recognizing that research often involves compromising the welfare of individuals. Where a research question can be answered without using live decapods, such alternative methods are preferred. Replacement could involve using existing data sets, as well as in vitro, organoid, and in silico approaches.
However, many research questions clearly require decapod crustaceans and, if that knowledge is sought, reduction and refinement become relevant. Reduction involves minimizing the number of decapods used for a given research aim (e.g., by using power analyses to determine the required sample size for statistical validity; Perl 2023) and maximizing the amount of information gained
from each individual (thus preventing excessive sampling). Refinement involves minimizing stress vectors and providing environmental conditions that are sensitive to the species’ natural history.
These guidelines focus on research that requires live decapod crustaceans. They emphasize practical methods for reducing the number of animals used as well as refining research and husbandry practices. The guidelines provide principled suggestions about best practices, none of which replace the professional judgment of researchers or technicians about how to meet the needs and interests of individual animals. Specific recommendations are tentative for two reasons. First, decapod species and research contexts are many and varied. While some general principles hold across them, specific recommendations may not. Second, there are significant uncertainties about decapod welfare and stress. Best practice will, therefore, evolve as knowledge advances.
These guidelines focus on the welfare of individual decapod crustaceans. They are not, therefore, comprehensive guidelines for ethical research. For instance, they presuppose compliance with federal, state, and local laws and regulations, institutional policies, and international conventions. Likewise, they presuppose environmental responsibility, the integrity of scientific results and academic conduct, non-discrimination, and managing conflicts of interest. While such ethical issues are important, they have been addressed elsewhere (e.g., in standard RCR training, typically available to all university-affiliated researchers). Those seeking more information about these ethical issues should consult other community resources and the appropriate authorities.
Questions about these guidelines should be directed to the IWRS ([email protected]).