Scientists confirm--Hurt crabs feel pain

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From ANIMAL PEOPLE, May 2009:

 

 

Scientists confirm--

Hurt crabs feel pain

 

BELFAST--Hermit crabs feel pain when

injured and change their behavior to avoid the

source of pain, reported Robert Elwood of the

School of Biological Sciences at Queen's

University in Belfast, Northern Ireland, on

March 27, 2009.

" With vertebrates we are asked to err on

the side of caution and I believe this is the

approach to take with crustaceans, " concluded

Elwood.

" Ripping the legs off live crabs and

crowding lobsters into seafood market tanks are

just two of the many practices that may warrant

reassessment, " warned Jennifer Viegas of the

Discovery Channel.

More than 4,130 news web sites amplified

Elwood's findings, soon to be published in the

journals Animal Behavior and Applied Animal

Behavior Science.

The hermit crab study was Elwood's second

well-publicized attempt to establish to the

satisfaction of most remaining scientific

skeptics that crustaceans feel pain. New

Scientist in November 2007 published Elwood's

findings about the behavior of 144 prawns after

he daubed one of their antennae with a solution

of diluted acetic acid. The prawns immediately

groomed and rubbed the daubed antennae, but not

their other antennae. This, Elwood wrote, was

" consistent with an interpretation of pain

experience. "

The Guardian headlined a report about the

prawn study " Blow for fans of boiled lobster. "

But other researchers alleged fault with Elwood's

experiment.

" Even a single-cell organism can detect a

threatening chemical gradient and retreat from

it, " University of Utah pain researcher Richard

Chapman told Guardian reporter Ian Sample.

Elwood designed the hermit crab study to

respond to the criticisms of the prawn study. He

and colleague Mirjam Appel collected hermit crabs

from rock pools in County Down, Northern Ireland.

" All of the crabs survived the

experiments and were later released back into

their native habitat, " reported Viegas.

Hermit crabs, rather than forming their

own shells, occupy shells discarded by other

animals. Once they find a satisfactory shell,

they are reluctant to abandon it. Their usual

response to a threat is to retreat farther into

the shell.

Elwood and Appel offered the hermit crabs

alternative shells to move into, but shells less

attractive to them than the shells they already

had.

Elwood and Appel then gave some of the

crabs small electric shocks while they were

inside their old shells.

hells. They also groomed themselves in a manner

that Elwood and Appel described as " a protective

motor reaction, viewed as a sign of pain in

vertebrates. " Crabs who were not shocked did not

take the opportunity to change shells.

" There has been a long debate about

whether crustaceans including crabs, prawns and

lobsters feel pain, " Elwood summarized in a

media release. " We know from previous research

that they can detect harmful stimuli and withdraw

from the source of the stimuli but that could be

a simple reflex without the inner 'feeling' of

unpleasantness that we associate with pain. This

research demonstrates that it is not a simple

reflex but that crabs trade their need for a

quality shell with the need to avoid the harmful

stimulus. "

 

Trade-offs

 

" Such trade-offs are seen in

vertebrates, " Elwood wrote, " in which the

response to pain is controlled with respect to

other requirements. Humans, for example, may

hold a hot plate that contains food, whereas

they may drop an empty plate, showing that we

take into account differing motivational

requirements when responding to pain.

" Trade-offs of this type have not been

previously demonstrated in crustaceans, " Elwood

continued. " The results are consistent with the

idea of pain being experienced by these animals. "

Elwood spoke specifically to the

treatment of crustaceans by the seafood industry.

" More research is needed in this area where a

potentially very large problem is being ignored, "

he said. " Legislation to protect crustaceans has

been proposed [in Britain] but is likely to cover

only scientific research. Millions of

crustaceans are caught or reared in aquaculture

for the food industry. There is no protection

for these animals, with the possible exception

of certain states in Australia. "

In Elwood's Applied Animal Behavior

Science paper, he and co-authors Stuart Barr and

Lynsey Patterson cite seven reasons for believing

that crustaceans suffer. In addition to the

findings of the hermit crab and prawn

experiments, they explain, crustaceans placed

under stress demonstrate physiological changes

consistent with feeling pain, including release

of adrenal-like hormones. If crabs are given

anesthetics or analgesics, they appear to feel

relieved, showing fewer responses to negative

stimuli.

Contrary to the supposition that having a

brain is necessary to feel pain, Elwood et al

argue, crustaceans have " high cognitive ability

and sentience. "

Feelings of pain and stress in mammals

are associated with the neocortex. Because

crustaceans lack a neocortex, prevailing belief

until recently was that they lack the

physiological structure necessary to suffer.

Responds Elwood, " Using the same

analogy, one could argue crabs do not have vision

because they lack the visual centres of humans. "

In fact, fish, lobsters and octopi all have

vision, and some species have relatively

advanced vision, despite lacking a visual

cortex. The explanation is that their

neurological systems are organized in a different

manner, with different control structures.

" It was also thought, " said Viegas of

the Discovery Channel, " that since many

invertebrates cast off damaged appendages, it

was not harmful for humans to remove legs, tails

and other body parts from live crustaceans.

Another study led by Lynsey Patterson, however,

found that when humans twisted off legs from

crabs, their stress response was so profound

that some later died. "

 

Humane response

 

Much of the humane community has believed

for decades that the treatment of crustaceans

should become a topic of urgent concern--if only

to avoid practices that might encourage callous

treatment of other species.

In 1952, for example, delegates from 25

nations agreed at a convention hosted by the

World Federation for the Protection of

Animals--one of the three ancestors of the World

Society for the Protection of Animals-- that

boiling live crustaceans sets a bad example of

how animals should be treated, and should be

abolished.

PETA has staged heavily publicized live

lobster releases almost annually for more than 25

years. In 2006 two members of Animal Rights

Croatia locked themselves into a fish tank to

dramatize the fate of lobsters.

Serious efforts have also been made by

the humane community to assemble scientific

evidence that crustaceans suffer. The Scottish

organization Advocates for Animals in 2005

published a volume entitled Cephalopods & Decapod

Crustaceans: Their Capacity To Experience Pain &

Suffering, assessing all that was known at that

time.

Such efforts have brought some results.

Notably, the grocery chain Whole Foods in 2006

quit selling live soft-shelled crabs and lobsters

for humane reasons.

But the humane community has also been

embarrassed by incidents such as a crab cook held

in 2005 to benefit the Prince Rupert SPCA. A

sequel was cancelled in 2006 by the British

Columbia SPCA, parent organization to the Prince

Rupert SPCA, after Sea Shepherd Conservation

Society founder Paul Watson led a campaign

against it.

 

Concern for fish

 

Concern about crustacean suffering is

rising parallel to campaigns on behalf of fish.

Hong Kong SPCA executive director Sandy

Macalister, for instance, editorialized

recently in the membership magazine Paw Prints

against the practice of restauranteurs keeping

giant groupers and other species on display in

cramped tanks, until bought and killed for

someone's dinner.

" These wonderful animals, which since

the 1940s have lived and bred in the coral

depths, now lie behind thick distorting glass in

a narrow tank on the footpath, " wrote

Macalister. " How many times have we walked past

such horrific living conditions for these animals

without a second thought? Is it because we

consider them to be `just fish'? If a passer-by

or a restaurant patron knew that these

magnificent creatures were more than 65 years

old, would that make a difference? "

Macalister's editorial attracted

extensive sympathetic coverage from Simon Parry

of the South China Morning Post.

" Fish are vertebrates like us, "

University of Hong Kong biologist Yvonne Sadovy

told Parry. " They have a backbone, and a lot of

the biology and physiology have some similarities

to us. Our nervous systems and hormonal systems

in some ways are very similar. I think most

biologists would say there is absolutely no

reason to believe they would not feel pain. How

they perceive it is obviously incredibly

difficult to know, but you pick up a fish and

take it out of water and put a hook in its mouth

and it struggles. There is something clearly

uncomfortable and not right and that fish

perceives stress. "

" When you consider what a fish does in

its daily life--it can tell where it is,

identify things and make decisions--it is clear

there's far more going on than anyone suspects, "

Macalister said. " They learn, and they have

memories, and they can identify people. They

feel stress and they feel pain. People used to

believe fish couldn't remember anything for

longer than three seconds, but we know now that

isn't true. "

Fish in Hong Kong, as in most of the

world, have only scant protection under existing

anti-cruelty laws, but Macalister pointed out

that laws follow public opinion.

" Attitudes, as well as the law, have to

change, " Macalister told Parry. " It's an issue

of education. "

Industry notice

Some people in the seafood industry are

also beginning to notice animal welfare issues.

Adam Anson, who writes for The Fish Site, The

Pig Site, The Beef Site, and other online

animal industry periodicals, noted in March 2009

that " Fish welfare needs have been left behind "

in developing the aquaculture industry, even

though " In 1997, the Treaty of Amsterdam agreed

that throughout the European Union the concept of

welfare is the same in fish as it is in mammals

and birds and necessary protection should be

applied. "

This concept was reinforced in an April

8, 2009 communication to the European Commission

by the EC Fisheries Directorate.

" This communication recognises the

importance of the welfare of farmed fish for the

development of sustainable aquaculture, "

summarized Eurogroup for Animal Welfare.

" Eurogroup is pleased to see that the Commission

plans to launch a project to evaluate fish

welfare in aquaculture with a view to possibly

introducing legislation on this topic, "

Eurogroup added.

Assessed Anson, " Research into this area

has not just been hampered by a lack of

investment, but also by the complexity of the

issue and the difficulty in achieving scientific,

relevant measurementsŠA further complexity is

added by the numerous different species of fish

that are now used in farming. Research must

identify all the varying degrees of behavioral

patterns and social activities. Welfare standards

must, in turn, take these natural drives into

account, applying unique welfare standards for

each different species. "

Noted Anson, " Some natural conditions

will be impossible to recreate in a fish pen.

For instance, Atlantic salmon will never be able

to make their monumental migrations, risking

life to reproduce, whilst trapped inside the

confines of a net.

" It is easy to see how fish welfare is a

complex and potentially very expensive issue for

the industry, " Anson concluded, " but the more

that is understood, the more necessary the

research seems. " --Merritt Clifton

 

 

 

--

Merritt Clifton

Editor, ANIMAL PEOPLE

P.O. Box 960

Clinton, WA 98236

 

Telephone: 360-579-2505

Fax: 360-579-2575

E-mail: anmlpepl

Web: www.animalpeoplenews.org

 

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