17 August 2020

New Zealand and lobster welfare

Jasus edwardsii
Oh, is it that time again? When I review a news story about crustacean welfare where someone wants to change policy around treatment of crustaceans who claims to be backed by scientific evidence? Which, upon review, turns out to be a cursory and / or one-sided view of that scientific evidence?

Yes, it’s that time.

New Zealand’s regulations for lobster welfare have been subject to a complaint from the New Zealand Animal Law Society, as reported here. They charge that the current regulations, which require making a lobster “insensible” by cooling, are not met. They argue that chilling causes lobsters “pain.”

I looked at the complaint and am unimpressed with the level of scientific evidence it brings to the table.

First, they argue that any finding on decapod crustaceans apply to lobsters. This is often a reasonable thing to do, but I am hesitant here. 

1. Lobsters are big crustaceans. And when you are talking about cooling, the size of the animals is important because of thermal inertia. A small animal will cool faster than a large one, and that could be highly relevant to the response.

2. Different crustacean species are adapted to different temperature. Colleagues of mine who usually chilled crustaceans to do experiments found chilling didn’t work at all on Anaspides. Not surprising if you know it lives in cold waters in Tasmania.

In “Part 4 – The Code is not based on current scientific knowledge,” the document repeatedly quotes the work of Robert Elwood and colleagues, citing “personal communication” with Elwood. Elwood claims his position is not controversial, but not all crustacean biologists agree with Elwood’s interpretations (Diggles 2018).

Elwood says there is “substantial” research on this topic.

There are still many very basic questions about crustacean neurobiology that are not answered. Do crustaceans have neurons tuned to tissue damage? It looks plausible (Puri and Faulkes 2015), but those neurons hasn’t been fully characterized. There is work to do.

They document cites one that tested the response of crustaceans to low temperature (Roth and Øines 2010) which is the entire subject of the complaint. But there more papers that address responses of crustaceans to low temperature directly (Weineck et al. 2018; Puri and Faulkes 2015). Not mentioning those papers indicates their literature review is either cursory or cherry-picked.

There are so many little things that are asserted with minimal evidence. The document says they have “complex” brains. That’s subjective. The document says that some crustaceans have more neurons than vertebrates – but does not give an example. Sure, I suspect that a fully grown adult lobster has more neurons than a larval zebrafish, say. That sort of claim needs a lot more context to show how it is relevant to the question.

I don’t have any particular opinion about whether lobsters “feel pain.” I want good animal welfare laws. But I do not want policies based on small slivers of the scientific literature coming from a small number of labs.

References

Diggles BK. 2018. Review of some scientific issues related to crustacean welfare. ICES Journal of Marine Science: fsy058. http://dx.doi.org/10.1093/icesjms/fsy058

Puri S, Faulkes Z. 2015. Can crayfish take the heat? Procambarus clarkii show nociceptive behaviour to high temperature stimuli, but not low temperature or chemical stimuli. Biology Open 4(4): 441-448. https://doi.org/10.1242/bio.20149654

Roth B, Øines S. 2010. Stunning and killing of edible crabs (Cancer pagurus). Animal Welfare 19(3): 287-294. https://www.ingentaconnect.com/content/ufaw/aw/2010/00000019/00000003/art00009

Weineck K, Ray A, Fleckenstein L, Medley M, Dzubuk N, Piana E, Cooper R. 2018. Physiological changes as a measure of crustacean welfare under different standardized stunning techniques: cooling and electroshock. Animals 8(9): 158. https://doi.org/10.3390/ani8090158

Related posts

Crustacean pain is still a complicated issue, despite the headlines

What we know and don’t know about crustacean pain

Switzerland’s lobster laws are not paragons of science-based policy

External links

Lobster slaughter methods causing significant pain and distress, Animal Law Society says

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