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Increasing global pressures for the collection of echinoderms for various commercial enterprises threatened these invertebrates and contributed to the ongoing concern of depletion of marine resources worldwide. Increasing global trade with the
collection of echinoderms for home aquariums, souvenirs, and biomedical products
as well as overfishing threatened some echinoderm species (Micael et al. 2009).
4.2 Sea Urchin
4.2.1 General Information About Sea Urchins
4.2.1.1 Biology of Sea Urchins
Sea urchins are members of a large group of marine invertebrates in the phylum
Echinodermata. All sea urchins have a hard-calcareous shell called a test, which is
covered with a thin epithelium and is usually armed with spines. The spines are used
for locomotion, for protection, and for trapping drifting algae for food. Between the
spines are tube feet that are used in food capture, for locomotion, and for holding on
to the substrate. Sea urchins also have small pinchers, called pedicellariae, that are
used for defence and for clutching food. The mouth is located on the underside. It
consists of a complex array of skeletal elements, plates, and teeth arranged in fivesymmetry called “Aristotle’s lantern.” The mouth leads to the digestive tract, which
empties through the anus located on the top of the test. The sexes are generally separate in sea urchins. Females release up to several million eggs into the sea, where
fertilization takes place (Price 2000). The reproduction periods of sea urchins vary
according to their habitat, and the most common months of ovulation are July and
August. The release of eggs and sperm into the sea water takes place through pores
located on ambulacral plaques (King et al. 1994). After a multistage planktonic
existence, the larvae settle and metamorphose to the characteristic form. In sea
urchins, the body is spherical or flattened. There are no arms and the most prominent feature is that the limestone plates interlock each other and form a shell. This
shell completely covers the other sides of the body, except for only two poles
(Price 2000).
Sea urchins, which have a wide variety and spread, are very important organisms
because they are the species that provide information about water pollution in their
regions. In addition to being of serious ecological importance, the consumption of
gonads in the food industry enables sea urchins to form an important place worldwide (Guidetti et al. 2004; Gianguzza et al. 2006).
4 Echinoderms
Increasing global pressures for the collection of echinoderms for various commercial enterprises threatened these invertebrates and contributed to the ongoing concern of depletion of marine resources worldwide. Increasing global trade with the
collection of echinoderms for home aquariums, souvenirs, and biomedical products
as well as overfishing threatened some echinoderm species (Micael et al. 2009).
4.2 Sea Urchin
4.2.1 General Information About Sea Urchins
4.2.1.1 Biology of Sea Urchins
Sea urchins are members of a large group of marine invertebrates in the phylum
Echinodermata. All sea urchins have a hard-calcareous shell called a test, which is
covered with a thin epithelium and is usually armed with spines. The spines are used
for locomotion, for protection, and for trapping drifting algae for food. Between the
spines are tube feet that are used in food capture, for locomotion, and for holding on
to the substrate. Sea urchins also have small pinchers, called pedicellariae, that are
used for defence and for clutching food. The mouth is located on the underside. It
consists of a complex array of skeletal elements, plates, and teeth arranged in fivesymmetry called “Aristotle’s lantern.” The mouth leads to the digestive tract, which
empties through the anus located on the top of the test. The sexes are generally separate in sea urchins. Females release up to several million eggs into the sea, where
fertilization takes place (Price 2000). The reproduction periods of sea urchins vary
according to their habitat, and the most common months of ovulation are July and
August. The release of eggs and sperm into the sea water takes place through pores
located on ambulacral plaques (King et al. 1994). After a multistage planktonic
existence, the larvae settle and metamorphose to the characteristic form. In sea
urchins, the body is spherical or flattened. There are no arms and the most prominent feature is that the limestone plates interlock each other and form a shell. This
shell completely covers the other sides of the body, except for only two poles
(Price 2000).
Sea urchins, which have a wide variety and spread, are very important organisms
because they are the species that provide information about water pollution in their
regions. In addition to being of serious ecological importance, the consumption of
gonads in the food industry enables sea urchins to form an important place worldwide (Guidetti et al. 2004; Gianguzza et al. 2006).
4 Echinoderms