20 September 2018

Giving lobsters weed

I’ve been studying issues roiling around the question of “Does it hurt lobsters when they go into a pot?” for about a decade. After ten years or so, you get a little jaded. I’m used to seeing the same bad arguments. I’m used to it popping up and making the rounds in news about twice a year. The first time this year was when Switzerland put laws into place about lobster handling. This is the second.

And I’ve got to say:

That’s new.

A Maine newspaper is reporting on a restaurant owner, Charlotte Gill, is sedating lobster with marijuana.

I am pretty sure cannabis as a sedative not been the subject of any peer-reviewed scientific papers on crustacean anesthesia. But a quick Google Scholar search (thank you thank you thank you Google for this tool) shows that spiny lobsters and other invertebrates have cannabinoid receptors (McPartland et al. 2005). This makes the technique plausible on the face of it.

The behavioural effects reported were interesting.

Following the experiment, Roscoe’s (the experimental lobster - ZF) claw bands were removed and kept off for nearly three weeks.

His mood seemed to have an impact on the other lobsters in the tank. He never again wielded his claws as weapons.

I am surprised by the apparent duration of the effects. Weeks of behaviour change from a single treatment? That seems long compared to soporific effects of marijuana smoke in humans doesn’t seem to last multiple days.

Earlier this week, Roscoe was returned to the ocean as a thank you for being the experimental crustacean.

I’m not sure of the ethics of this. Will Roscoe the lobster, who has apparently forgotten how to use claws, going to become a quick meal for a predator? A lobster without claws in the ocean is just bait (Barshaw et al. 2003). Releasing Roscoe may doom him!

I am a little concerned by what seems to be Gill’s quick dismissal of other techniques:

In Switzerland, the recommended method of cooking the crustacean is to electrocute it or stab it in the head before putting it in the boiling water.

“These are both horrible options,” said Gill. “If we’re going to take a life we have a responsibility to do it as humanely as possible.”

I don’t know if she has anything but intuition to support that opinion. There’s research on electrical stunning, and the results so far are mixed. Fregin and Bickmeyer (2016) found shocks “do not mitigate the response to external stimuli,” but Neil (2012), Roth and Grimsbø (2016), and Weineck et al. (2018) found electric shocks seemed to knock down neural activity effectively. But the impression I get is that using shock is tricky: you need different protocols for different animals.

It’s also worth noting that a new paper by Weineck et al. (2018) showed chilling was effective as an anesthetic, which the Swiss regulations forbade. Research I co-authored (Puri and Faulkes 2015) showed no evidence that crayfish responded to low temperature stimuli.

Of course, another complication around this technique is its legality. The legal landscape around marijuana in the U.S. is tricky. Marijuana is still regulated federally, but certain states permit different kinds of uses. The article notes:

Gill holds a medical marijuana caregiver license with the state and is using product she grows in order to guarantee its quality.

This is interesting, but it’s not clear to me that this is a more cost effective or humane way to sedate a lobster than what many crustacean researchers have been doing for a long time: cooling on crushed ice.

Hat tip to Mo Costandi.


Barshaw DE, Lavalli KL, Spanier E. 2003. Offense versus defense: responses of three morphological types of lobsters to predation. Marine Ecology Progress Series 256: 171-182. https://doi.org/10.3354/meps256171

Fregin T, Bickmeyer U. 2016. Electrophysiological investigation of different methods of anesthesia in lobster and crayfish. PLOS ONE 11(9): e0162894. https://doi.org/10.1371/journal.pone.0162894

McPartland JM, Agraval J, Gleeson D, Heasman K, Glass M. 2006. Cannabinoid receptors in invertebrates. Journal of Evolutionary Biology 19(2): 366-373. https://doi.org/10.1111/j.1420-9101.2005.01028.x

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, Grimsbø E. 2016. Electrical stunning of edible crabs (Cancer pagurus): from single experiments to commercial practice. Animal Welfare 25(4): 489-497. https://doi.org/10.7120/09627286.25.4.489

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. http://www.mdpi.com/2076-2615/8/9/158

Related posts

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

External links

“Hot box” lobsters touted
Maine restaurant sedates lobsters with marijuana
New England marijuana laws – where it’s legal, where it’s not and what you need to know

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