260
and Nordin 1979). The baskets come to the packaging line after immersion in salted
ice water and potassium solution to maintain the firm texture of the roe. The highest
quality roe should be of uniform size, firm texture, attractive colour, and optimum
maturity. Some high-end roe is packed into plastic trays or cups destined for the
Japanese supermarket trade. The highest quality roe is purchased by buyers from
sushi bars and restaurants, who prepare the fresh roe and repackage and combine it
with other products in a meal. Some of the higher quality urchins are sold by supermarkets and fish retailers serving household consumption. Sea urchins are generally
purchased from supermarkets to consume on special occasions. There is also a relatively important gift market, where uni is packaged and processed in various ways
and sold with catalogues for special occasions. These are given as gifts for special
occasions such as the New Year, welcome parties, and visits to relatives or friends.
It is sometimes sold mixed with other products. In such products, lower quality, less
mature, smaller, less hard urchins are used. These low-quality roes are also used in
dried, salted, baked and frozen products (Reynolds and Wilen 2000). Wholesalers
play an important role in distributing sea urchins to various buyers, such as restaurants (mainly Japanese style restaurants), supermarkets, fish markets, and catering
companies (Sun and Chiang 2015).
4.3 Sea Cucumbers
4.3.1 General Information About Sea Cucumbers
4.3.1.1 Biology of Sea Cucumbers
Sea cucumbers are echinoderms from the class Holothuroidea. They are marine
animals with a leathery skin and an elongated body containing a single, branched
gonad. Like all echinoderms, sea cucumbers have an endoskeleton just below the
skin, calcified structures that are usually reduced to isolated microscopic ossicles
joined by connective tissue. In some species these can sometimes be enlarged to
flattened plates, forming armour. In pelagic species such as Pelagothuria natatrix,
the skeleton is absent and there is no calcareous ring. Most sea cucumbers, as their
name suggests, have a soft and cylindrical body, lengthened, rounded off and occasionally fat in the extremities, and generally without solid appendages. Their shape
ranges from almost spherical for “sea apples” to serpent-like for Apodida or the
classic sausage-shape, while others resemble caterpillars. The mouth is surrounded
by tentacles, which can be pulled back inside the animal. The body of a holothurian
is roughly cylindrical. It is radially symmetrical along its longitudinal axis and has
weak bilateral symmetry transversely with a dorsal and a ventral surface. There are
five ambulacra separated by five ambulacral grooves, the interambulacral. The
ambulacral grooves bear four rows of tube feet but these are diminished in size or
absent in some holothurians, especially on the dorsal surface. The two dorsal
4 Echinoderms
and Nordin 1979). The baskets come to the packaging line after immersion in salted
ice water and potassium solution to maintain the firm texture of the roe. The highest
quality roe should be of uniform size, firm texture, attractive colour, and optimum
maturity. Some high-end roe is packed into plastic trays or cups destined for the
Japanese supermarket trade. The highest quality roe is purchased by buyers from
sushi bars and restaurants, who prepare the fresh roe and repackage and combine it
with other products in a meal. Some of the higher quality urchins are sold by supermarkets and fish retailers serving household consumption. Sea urchins are generally
purchased from supermarkets to consume on special occasions. There is also a relatively important gift market, where uni is packaged and processed in various ways
and sold with catalogues for special occasions. These are given as gifts for special
occasions such as the New Year, welcome parties, and visits to relatives or friends.
It is sometimes sold mixed with other products. In such products, lower quality, less
mature, smaller, less hard urchins are used. These low-quality roes are also used in
dried, salted, baked and frozen products (Reynolds and Wilen 2000). Wholesalers
play an important role in distributing sea urchins to various buyers, such as restaurants (mainly Japanese style restaurants), supermarkets, fish markets, and catering
companies (Sun and Chiang 2015).
4.3 Sea Cucumbers
4.3.1 General Information About Sea Cucumbers
4.3.1.1 Biology of Sea Cucumbers
Sea cucumbers are echinoderms from the class Holothuroidea. They are marine
animals with a leathery skin and an elongated body containing a single, branched
gonad. Like all echinoderms, sea cucumbers have an endoskeleton just below the
skin, calcified structures that are usually reduced to isolated microscopic ossicles
joined by connective tissue. In some species these can sometimes be enlarged to
flattened plates, forming armour. In pelagic species such as Pelagothuria natatrix,
the skeleton is absent and there is no calcareous ring. Most sea cucumbers, as their
name suggests, have a soft and cylindrical body, lengthened, rounded off and occasionally fat in the extremities, and generally without solid appendages. Their shape
ranges from almost spherical for “sea apples” to serpent-like for Apodida or the
classic sausage-shape, while others resemble caterpillars. The mouth is surrounded
by tentacles, which can be pulled back inside the animal. The body of a holothurian
is roughly cylindrical. It is radially symmetrical along its longitudinal axis and has
weak bilateral symmetry transversely with a dorsal and a ventral surface. There are
five ambulacra separated by five ambulacral grooves, the interambulacral. The
ambulacral grooves bear four rows of tube feet but these are diminished in size or
absent in some holothurians, especially on the dorsal surface. The two dorsal
4 Echinoderms