Lobster welfare: serious welfare issues for lobsters in the UK, with focus on slaughter

14 April 2023

Introduction

Lobster consumption is increasing (Conte et al., 2021). In previous decades their sentience was not recognised and there was little concern for their welfare (Sherwin, 2001). Despite some authors maintaining that literature on pain in decapod crustaceans (which includes lobsters) is weak (Diggles, 2019; Sneddon, 2018; Puri, 2015; Rose, 2014), recent studies have concluded that decapod crustaceans are sentient and therefore should be protected (Broom, 2016; Elwood, 2012; Elwood, 2019; Sherwin, 2001). Government department DEFRA commissioned an independent external review to examine invertebrate sentience, including lobsters, to see if they should be recognised under The Animal Welfare (Sentience Bill) (Ares, 2022). The report concluded that decapod crustaceans should be regarded as sentient (Birch et al., 2021) and Government consequentially confirmed an amendment to the Bill including decapod crustaceans (DEFRA, 2021). The recognition of their sentience is undoubtedly progress, and there are reports that this inclusion would mean the banning of boiling alive of lobsters, a controversial slaughter method (Royal Veterinary College University of London, 2021). However, what are the realisations of their life and death? This essay reviews welfare issues during life and at slaughter for lobsters in the UK, citing lobster research and, where appropriate, research on other decapods extended to lobsters.

Welfare during life

Lobsters face numerous welfare issues arising from specific practices. They are not currently farmed, although research projects have assessed the potential (Innovate UK, 2015). Accidental injury of lobsters occur during capture, handling, transport and sale (Birch et al., 2021; Lavallee et al., 2000). Trauma includes loss of limbs, injured antennae, cracked carapaces (outer shell) and crush injuries (Birch et al., 2021; Basti et al., 2010). Cracks can cause leaking of haemolymph (internal fluid), causing death (Basti et al., 2010). Catching and trawling, used to collect lobsters, both risk injury (Birch et al., 2021). Handling causes physiological stress (Jacklin & Combes, 2005). Aggression and social stress occur when lobsters, who are naturally solitary animals (Birch et al., 2021), are grouped together in traps, storage and in tanks (Birch et al., 2021). High stocking densities are common (Carder, 2017), with up to 50 lobsters in a single tank (Birch et al., 2021). Temperature variations are also a welfare issue. Warmth causes loss of vigour (Lavallee et al., 2000; Jacklin & Combes, 2005) whereas sudden cold such as ice can stress or even kill decapods (Jacklin & Combes, 2005). Food is withheld during storage. Research shows that resistance to starvation varies and is a potential welfare issue (Albalat et al., 2019). Lobsters inhabit dark areas, however this environment is commonly denied (Carder, 2017). Delivery to and care in consumer homes has inherent welfare issues for live lobsters (Birch et al., 2021).

Welfare at stunning and slaughter

Lobsters, in commercial, restaurant or home settings, face slaughter. Various methods of stunning and slaughter are used and debated, which are discussed below. They include electrical, pharmaceutical and chill stunning, and slaughter via electrical, chilling, boiling, mechanical and others means. The term ‘stunning’ refers to inducing unconsciousness. The general principle of humane slaughter is that death occurs quickly with minimal pain, suffering and fear (European Union, 2009). The key element for this is loss of consciousness and the speed it is achieved by the method (Conte et al., 2021).

Concerns are raised over stunning and slaughter methods. Stunning concerns including whether the animal experiences distress during stunning and whether stunning actually works (such as causing paralysis rather than unconsciousness). Slaughter concerns include the presence, severity and longevity of pain and distress prior to death. It is worth noting that generally slaughter methods have been developed with production efficiency, quality control and human safety in mind, not welfare (Conte, 2004). We will first examine the proposed most promising stunning and slaughter method for welfare; electrical.

Electrical

Electric shocks applied to neural tissue can stun and (at higher or longer time lengths) kill lobsters (Birch et al., 2021). Electrical stunning produces a seizure-like state in lobsters, according to current evidence (Birch et al., 2021). It is suggested that electrical stunning has been demonstrated to ‘cause an immediate interruption in the functions of the nervous system’ (Conte et al., 2021). Crustastun units (stunning equipment) used in the UK are designed to stun and kill. Electrical stunning and slaughter is hailed, by many in the field including Crustacean Compassion, as the preferred method because it is claimed to be both quick (under one second) and effective (Conte et al., 2021; Crustacean Compassion, n.d.; Neil, 2012a; Neil, 2012b; Fregin & Bickmeyer, 2016; Weineck, 2018). Researchers at Glasgow University concluded Crustastun units caused no stress to the animals, based on haemolymph lactate levels (Neil & Thompson, 2012). However, the Government commissioned review report examines research in detail and highlights concerns meaning electrical methods are not fully proven. Various studies which are used to support electrical stunning are not formally peer-reviewed, and therefore only give the authors ‘medium confidence’. For example, Neil and Thompson (2012), mentioned above, tested six lobsters and concluded the Crustastun does not increase stress based on haemolymph lactate levels compared to a control group. However, the report, on examining this study points out that lack of a significant result does not confirm lack of an effect, that another study, peer-reviewed, did show increase of haemolymph lactate (Elwood & Adams, 2015) and states it is impossible to conclude from this it was painless (Stevens et al., 2016). Stress is only one potential suggestion of pain (Elwood, 2016), and as only one indicator was measured on a small sample it is ‘poor evidence that high-voltage shocks do not induce pain.’ (Birch et al., 2021). Moreover, the report states despite ‘diminished neural activity and behavioural unresponsiveness we are not in a position to conclude that electrical stunning produces total anaesthesia’ which is very concerning, and concludes that we do not know what the animal experiences during the seizure (Birch et al., 2021).

Mechanical

Lobsters are also slaughtered by mechanical means. They have a decentralised nervous system made up of 13 interconnected ganglia, unlike vertebrates, and therefore methods targeting just the brain will be ineffective (Roth & Øines, 2010). ‘Splitting’ is a process to severe all 13; a longitudinal midline knife incision. However, chefs commonly only split the head, leaving posterior ganglia intact, raising welfare concerns. Report concluded that full body splitting when done by a skilled person is relatively quick, however also acknowledge it should take less than 10 seconds but is ‘often slower than one would ideally like’ at over 10 seconds (Birch et al., 2021). There is a risk to animal welfare. ‘Tailing’ (detaching the thorax from the abdomen or head) is not humane (Conte et al., 2021).

Chilling

Extreme cold temperatures using air or ice water are sometimes used to stun and kill lobsters. In too-low temperatures lobsters enter a state of torpor (Birch et al., 2021) and cease to respond.

Critically, there is concern over whether chilling does indeed stun and whether the process is painful.

The extreme cold was thought to have an anaesthetic effect due to lobster inactivity. Serious welfare concern is raised over whether it is actually paralysis, without an anaesthesia effect, and therefore the lobster remains conscious and able to feel pain (Gardener, 2004; Birch et al., 2021; Conte et al, 2021). In fact, Mood (2014) notes that there is no evidence that chilling induces anaesthesia rather than paralysis alone. There is also concern the extreme cold may also cause pain (Birch et al., 2021). Chilling should not be used to stun or kill, based on welfare grounds above, as well as the length of time taken to reach torpor and death (Crustacean Compassion, n.d.).

Boiling                                                               

Boiling of live lobsters is a known controversial method of slaughter. Despite immersion in boiling water being banned in various areas (New Zealand, Switzerland and parts of Italy) it is common in UK kitchens (Birch et al., 2021). Boiling produces numerous behaviours suggestive of aversion and physiological response of shock; escape attempts, thrashing, struggling (Elwood, 2012; Elwood, 2019; Yue, 2008). They take minutes to die which raises serious welfare concerns (Roth and Øines, 2010). Many have condemned boiling. Some authors have suggested chilling prior to immersion in water which is slowly heated as less responses were seen (Fregin & Bickmeyer, 2016). However, a lack of behavioural responses to boiling may not indicate total anaesthesia (Birch et al., 2021). Also concerning, is the suggestion in literature that chilling prior to boiling increases time taken to death (Yue, 2008).

Other methods

Pharmaceutical stunning may be a possible alternative to electrical stunning. However, it is rarely used in the UK, and moreover more research is required (Birch et al., 2021). Serious welfare concerns have been raised over slaughter methods, including; freshwater immersion (causing osmotic shock; essentially drowning) which is a prolonged death (Birch et al., 2021; Yue, 2008; EFSA, 2005), use of CO2 which causes distress and high water pressure proposed to be painful (Birch et al., 2021).

Summary

In summary, most stunning and slaughter methods have been ruled as inhumane, while other methods have now raised serious questions over whether they are as effective as previously thought. Numerous authors call for more research as there is a knowledge gap. The Humane Slaughter Association is currently funding research into crustacean slaughter for this reason (Birch et al., 2021). Moreover, much of the weighing up of which method is preferred is proffered in the context of which is the least bad. This means the recommended methods are not free of welfare issues.   

Conclusion

Lobsters are sentient creatures, now being recognised as such. They face welfare issues during their lives and deaths under human control. Numerous stunning and slaughter methods have been used, however none are without concern and authors call for more research, while lobsters continue to be slaughtered in the meantime.

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