Clawed
lobsters comprise a
family (
Nephropidae,
sometimes also
Homaridae) of large marine
crustaceans. Lobsters are economically important
as
seafood, forming the basis of a global
industry that nets more than
US$1 billion annually.
Though several groups of crustaceans are known as "lobsters," the
clawed lobsters are most often associated with the name. They are
also revered for their flavor and texture. Clawed lobsters are not
closely related to
spiny lobsters or
slipper lobsters, which have no
claws (
chelae), or
squat lobsters. The closest relatives of
clawed lobsters are the
reef lobsters
and the three families of freshwater
crayfish.
Biology
Lobsters are found in all oceans. They live on rocky, sandy, or
muddy bottoms from the shoreline to beyond the edge of the
continental shelf. They generally live
singly in crevices or in burrows under rocks.
They are
invertebrates, with a hard
protective
exoskeleton. Like most
arthropods, lobsters must
molt in order to grow, which leaves them vulnerable.
During the molting process, several species change color. Lobsters
have 10 walking legs; the front two adapted to claws.
As arthropods, lobsters have not developed the nervous system of
cephalopod mollusks, nor do they have the advantages of good
eyesight. They do, however, exhibit three remarkable evolutionary
advances that have led to their great success. Their exoskeleton is
a strong, lightweight, form-fitted external covering and support.
They display striated muscle: quick, strong, and lightweight, it
enables rapid movement and flight. Finally,
articulated appendages allow their limbs to
bend at specific points.
Lobsters, omnivores, typically eat prey live: fish, mollusks, other
crustaceans, worms, and some plant life. They scavenge if
necessary, and may resort to
cannibalism
in captivity; however, this has not been observed in the wild.
Although lobster skin has been found in lobster stomachs, this is
because lobsters eat their shed skin after
molting.
Although clawed lobsters, like most other arthropods, are largely
bilaterally symmetrical, they
often possess unequal, specialized claws, like the
king crab. The claw of a freshly caught lobster is
full and fleshy, not atrophied. Lobster anatomy includes the
cephalothorax which fuses the head and
the
thorax, both of which are covered by the
chitinous carapace
and the abdomen. The lobster's head consists of
antennae, antennules,
mandibles, the first and second
maxillae, and the first, second,
and third
maxillipeds. Because
lobsters live in a murky environment at the bottom of the ocean, it
mostly uses its antennae as sensors. The lobster eye has a
reflective structure atop a convex retina. In contrast, most
complex eyes use refractive ray concentrators (lenses) and a
concave retina. The abdomen includes
swimmerets and its tail is composed of
uropods and the
telson.
Lobsters, like snails and spiders, have blue blood due to the
presence of
haemocyanin, which contains
copper. (In contrast, mammals and many other
animals have red blood from
iron-rich
haemoglobin). Inside lobsters is a green viscous
substance called
tomalley, which serves as
the
hepatopancreas, functioning as
both liver and pancreas.
In general, lobsters are and move by slowly walking on the bottom
of the sea floor. However, when they flee, they swim backwards
quickly by curling and uncurling their
abdomen. A speed of five
meters per second (about 11 mph) has
been recorded. This is known as the
caridoid escape reaction.
Symbion
Animals of the genus
Symbion, the
only member of the animal phylum Cycliophora, live on lobster
gills and mouthparts. To date it has only been
found associated with lobsters.
Longevity
Recent research has led scientists to believe that lobsters may be
one of a small number of species which do not die of aging.
Lobsters do not slow down, weaken, or lose fertility with age. In
fact, older lobsters are more fertile than younger lobsters. The
reason for this infinite longevity is said to be due to
telomerase, an
enzyme that
repairs
DNA sequences of the form "TTAGG". This
sequence is often referred to as the telomeres of the DNA. In fact,
lobsters may exhibit
negligible
senescence, in that they effectively live indefinitely, barring
injury, disease, capture, etc. They can thus reach impressive
sizes.
According to the Guinness World Records, the largest
lobster was caught in Nova
Scotia
, Canada
, and weighed
.
Gastronomy
Lobster recipes include
Lobster
Newberg and
Lobster Thermidor.
Lobster is used variously, for example in soup,
bisque or lobster rolls. Lobster meat may be
dipped in
clarified butter,
resulting in a sweetened flavor.
Cooks boil live lobsters in water or steam. The lobster simmers for
seven minutes for the first pound and three minutes for each
additional pound.
Lobsters are also fried, grilled, or baked.
Lobsters are sold alive with claws strapped or banded to prevent
them from injuring each other or people. The banding causes the
claws to gradually
atrophy. Lobsters may be
prepared and cooked while alive; removing their claws may not kill
them. As with all
shellfish, lobster is
not
kosher. The majority of the meat is in
the tail and the two front claws. The legs and
torso contain smaller quantities.
Freezing the lobster may toughen the meat. A common
misconception is that a lobster screams when boiled; actually the
whistling sound is steam escaping the shell.
History
The
European wild lobster, including the royal blue lobster of Audresselles
, is more expensive and rare than the American
lobster. It was consumed chiefly by the royal and
aristocratic families of France
and the
Netherlands
. Such scenes were depicted in
Dutch Golden Age paintings of the
sixteenth and seventeenth centuries.
In North America, the American lobster did not achieve popularity
until the mid-19th century, when New Yorkers and Bostonians
developed a taste; not until the invention of a special vessel, the
lobster smack, did a commercial
fishery flourish.
Prior to this time, lobster was considered a
mark of poverty or as a food for indentured servants or lower
members of society in Maine
, Massachusetts
and the Canadian Maritimes. Into the 1950s, people in these
regions buried their lobster shells to escape the stigma.
and servants specified in employment agreements that they would not
eat lobster more than twice per week. In Canada, outside of the
rural outposts lobster was sold canned.
New England's fresh
lobster trade extended as far as Philadelphia
.
The lobster market changed once the transportation industry could
deliver live lobsters to urban centers.
Fresh lobster became a
luxury food and a tourist attraction for
the Maritime provinces and a luxury export to Europe and Japan
where it is
especially expensive.
Lobster's high price led to the creation of "faux lobster". It is
often made from
pollock or other
whitefish. A few restaurants sell
"
langostino lobster". Langostino
translates into
prawn; the actual animal may
be crab. The spiny lobster is also called
langouste.
Capacity for pain
Due to the ambiguous nature of
suffering,
the issue of lobster pain may be argued by analogy—that lobster
biology is similar to human biology or that lobster behavior
warrants assumptions that lobsters can feel pain.
The Norwegian Scientific Committee for Food Safety tentatively
concluded that "it is unlikely that [lobsters] can feel pain,"
though they note:
"there is apparently a paucity of exact knowledge on
sentience in crustaceans, and more research is
needed."
This conclusion is based on the lobster's simple nervous system.
The report assumes that the violent reaction of lobsters to boiling
water is a reflex to noxious stimuli.
However, review by the Scottish
animal
rights group Advocate for Animals released the same year
reported:
"scientific evidence ... strongly suggests that there
is a potential for [lobsters] to experience pain and
suffering,"
primarily because lobsters (and other
decapod crustaceans) "have opioid receptors and
respond to
opioids (
analgesics such as
morphine) in a similar way to vertebrates,"
indicating that lobsters' reaction to injury changes in the
presence of painkillers. The similarities in lobsters' and
vertebrates' stress systems and behavioral responses to noxious
stimuli were given as additional evidence.
A 2007
study at Queen's University, Belfast
, suggested that crustaceans do feel pain. In
the experiment, when prawn antennae were rubbed with sodium
hydroxide or acetic acid, the animals showed increased grooming of
the afflicted area and rubbed it more against the side of the tank.
Moreover, this reaction was inhibited by a local anesthetic, even
though control prawns treated with only anesthetic did not show
reduced activity. Professor
Robert
Elwood, who headed the study, argues that sensing pain is
crucial to prawn survival, because it encourages them to avoid
damaging behaviors. Some scientists responded, saying the rubbing
may reflect an attempt to clean the affected area.
In a 2009 study, Prof. Elwood and Mirjam Appel showed that
hermit crabs make motivational tradeoffs between
shocks and the quality of the shells they inhabit. In particular,
as crabs are shocked more intensely, they become increasingly
willing to leave their current shells for new shells, and they
spend less time deciding whether to enter those new shells.
Moreover, because the researchers did not offer the new shells
until after the electrical stimulation had ended, the behavior
change resulted from memory of the noxious event, not an immediate
reflex.
Opioids
In vertebrates, endogenous
opioids are
neurochemicals that moderate pain by
interacting with
opiate receptors. Opioid
peptides and opiate receptors occur
naturally in crustaceans, and although The Norwegian Scientific
Committee for Food Safety claims that “at present no certain
conclusion can be drawn,” critics interpret their presence as an
indication that lobsters experience pain. The aforementioned
Scottish paper holds that vertebrates and lobsters' opioids may
"mediate pain in the same way".
Morphine, an analgesic, and
naloxone, an opioid receptor antagonist, may affect
a related species of crustacean (
Chasmagnathus granulatus) in
much the same way they affect vertebrates: injections of morphine
into crabs produced a dose-dependent reduction of their defensive
response to an electric shock. (However, the attenuated defensive
response could originate from either the analgesic or sedative
properties of morphine, or both.) These findings have been
replicated for other invertebrate species, but similar data is not
yet available for lobsters.
Animal welfare issues
The most common way of killing a lobster is by placing it, live, in
boiling water, or by splitting: severing the body in half,
lengthwise.
The boiling method (also used to kill crabs, crayfish and shrimp)
is controversial because some believe that the lobster suffers.
The
practice is illegal in some places, such as in Reggio Emilia
, Italy, where offenders face fines of up to
€495. The Norwegian study states that
the lobster may be de-sensitized by placing it in a salt solution
15 minutes before killing it.
In 2006, British inventor Simon Buckhaven invented the
Crustastun, which electrocutes lobsters with
a 110 V
electric shock, killing them
in five seconds. This ensures a quicker death for the lobster.
Seafood wholesalers in Britain use a commercial version. A home
version was released to the public in about 2006.
Fishery and aquaculture
Lobsters are caught using baited, one-way traps with a color-coded
marker buoy to mark cages. Lobster is fished in water between 1 and
500 fathoms, although some lobsters live at 2,000 fathoms. Cages
are of plastic-coated galvanized steel or wood. A lobster fisher
may tend as many as 2,000 traps. Around the year 2000, due to
overfishing and high demand,
lobster
farming expanded. As of 2008, no lobster farming operation had
achieved commercial success.
In human culture
The
Moche people of ancient Peru
worshipped
the sea and its animals. Moche art often depicted
lobsters.
Lobsters dance a "Lobster Quadrille" in the eponymous chapter of
Lewis Carroll's famous book
Alice in Wonderland. It
and the related lobster poems can be read
here:
"Will you, won’t you, will you, won’t
you, won’t you join the dance?" and
"Tis the voice of the
Lobster; I heard him declare."
List of clawed lobster species
This list contains all known species in the family
Nephropidae:
References
-
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/T/Telomeres.html
-
http://animals.howstuffworks.com/marine-life/400-pound-lobster.htm/printable
-
http://www.npr.org/templates/story/story.php?storyId=11382976
- Emerging Area of Aging Research: Long-Lived Animals with
"Negligible Senescence", John C. Guerin. Annals of the New
York Academy of Sciences 1019 (1) , 518–520. ( abstract)
- Woodard, Colin. The
Lobster Coast. New York. Viking/Penguin, ISBN
0-670-03324-3, 2004, pp. 170-180
- Do Most People Know What They're Eating? |
Metafilter
- Maine Today : Comments
- How lobster went up in the world, The Times
Online
- Sample, Ian. "Blow for fans of boiled lobster: crustaceans feel
pain, study says", The Guardian, Nov 8, 2007.
- Berrin, Katherine & Larco Museum. The Spirit of Ancient
Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera.
New York: Thames and Hudson, 1997
- Chapter X, Alice in Wonderland, Lewis
Carroll
External links