2012 COURSE DATES: AUGUST 4 – 17, 2012 - Sirenian International

Variegated Sea Urchin
Lytechinus variegatus
Kalie Bishop
Ecology and Behavior of Manatees and
Dolphins in
Belize, Class of 2011 (contact:
cselfsullivan@sirenian.org)
Taxonomy
Kingdom: Anamalia
Phylum: Echinodermata
Class: Echinoidea
Order: Temnopleuroida
Family: Toxopneustida
Genus: Lytechinus
Species: Lytechinus variegates
Ecology
L. variegatus is commonly found in shallow,
calm waters, such as seagrass beds. They
have adapted to survive in many marine
environments but primarily subsist within
seagrass and kelp beds. L. variegatus
inhabits the waters from North Carolina and
Bermuda southward to the Caribbean and
Brazil (Hendler et al. 1995). Although they
cannot live in freshwater, they inhabit all
depths and climates of the oceans.
Physical Description
L. variegatus vary in color, but the most
frequently seen are green, purple and light
pink. L. variegatus have radially symmetrical
bodies divided into five equal parts. The
skeletal structure of the sea urchin is a rigid
test or theca that is made up of plates
encircling the mouth in the center of the oral
side, encompassing the urchins inner
organs (Nichols 1962). Spines, which can
regenerate, cover the entire surface of the
sea urchin test and play a role in protection
as well as movement. Among the spines are
five paired rows of tiny tube feet with
suckers that help with locomotion, capturing
food, and holding onto the seafloor.
White variation of L. variegatus
Behavior
L. variegatus feed on decaying matter, kelp,
sea grass, algae and occasionally even sea
urchin skeletons. Sea urchins reproduce by
releasing the unfertilized eggs and sperm
into the water column, where the eggs are
fertilized and develop into free-swimming
larvae known as plutei (Pechenik 2000;
Harvey 1956). The larval form
of L. variegatus, as with most echinoderms,
is very different from the adult form and
must undergo a complex metamorphosis to
reach adult form.
Conservation
Being primary grazers of kelp, and algae, L.
variegatus play an important role within the
marine communities that they inhabit. The
population of L. variegatus in an area is vital
to the health of the coral reef, as they
eliminate the seaweed and algae that can
consume coral if a balance is not
maintained within the environment. The
opposite can also occur with an increase in
L. variegatus causing erosion on coral reef.
It is crucial to have balance within the
environment to maintain healthy
populations, such as the population on
Spanish lookout Caye.