Have you ever seen a blue
lobster? One
lobster in a million is blue and the explanation involves biology,
chemistry and physics!
Lobstermen in Maine find a blue lobster every year
or two, and such rarities generally find their way to aquariums. This one
lives at the Mt.
Desert Oceanarium & Lobster Hatchery in Bar Harbor,
Maine, one of the fascinating places my husband and I visited during our
vacation to Maine this summer.
Why
are some lobsters blue?
First, you have to know that the normal greenish-brown color of live
lobsters results from a combination of red and blue pigments in the
shell. The red pigment is
called astaxanthin (let's
call it pigment A).
Pigment A is a cousin of beta carotene, which gives carrots their orange color
and is a source of vitamin A. It also colors shrimp shells and salmon
flesh. Pigment A looks red because it absorbs blue light. The blue pigment in lobster
shells is called crustacyanin (we'll
call it pigment C).
Pigment C is actually just several molecules of pigment A clumped
and tied together with a protein molecule.
Dr. Harry A. Frank, a professor of chemistry at the University of
Connecticut, and his colleagues believe that the blue color results when
the protein pulls two molecules of pigment A so close to each other that
it changes the orbits of the electrons in the molecules causing them to
absorb red light (instead of blue) and appear blue (instead of red).
In the blue lobsters, a genetic mutation has caused an overabundance of
the pigment A-wrapping proteins, tying up all of the red pigment A (astaxanthin)
into blue pigment C (crustacyanin).
Why are blue lobsters so rare?
The normal mottled greenish-brown color blends in with the ocean floor
and provides camouflage. As a result, blue lobsters in the wild
stand out and usually get eaten long before they reach adult size.
What happens when
you cook a blue lobster?
Heat breaks down the
astaxanthin-wrapping protein, destroying the blue pigment. In other words,
on a dinner plate, a blue lobster would probably be just like any other
lobster: red.
Do lobsters come in other colors?
Lobsters may come in a variety of colors besides the usual
brown/green/blue,
including yellow, red, and white. Some even come in two colors,
having half of their shell one color and the other half a totally
different color. Of these only the white ones (true albinos) don't turn
red when cooked.
What are some other
facts about lobsters?
Lobster blood is a clear fluid. When the
animal is boiled, the blood turns to an opaque whitish gel. It has no
noticeable flavor and is perfectly safe to eat.
Lobsters can regenerate legs, claws, and antennae. In fact they can
amputate their own claws and legs to escape danger.
Lobsters exhibit 'handedness'. Some animals will have the crusher claw on
the right side while others will have it on the left.
Lobsters molt (shed their shells) to grow. They secrete enzymes that
soften the shell and connective shell joints. The shell splits up the back
and the creature backs out leaving it behind...including the membrane that
covered the eyes. They will increase their size by about 20% at every
molt.
