PART - IBIOLOGY AND CULTURE OF ABAL

PART - I
BIOLOGY AND CULTURE OF ABALONE

CHAPTER I
SPECIES AND THEIR GEOGRAPHICAL DISTRIBUTION

1.1 Species

There are about 100 species of abalone distributed throughout the world's oceans. Large abalones are mainly distributed in the temperate zone, while small specimens are typically found in the tropics and the cold zones. Ten species are considered of commercial value, and mainly occur in Korea, Japan, Mexico, South Africa, Southern Australia, New Zealand, United States of America, and China.

1.2 Geographical distribution

Haliotis discus hannai is an important species in Korea. They are distributed in the East and West coasts and are also found along the Liaodong and Shandong peninsula in China. In our country the measurement of isothermal line is conducted in which water temperature in 25 meters depth reaches 12 °C in February. With the isothermal line as a basis for identification, abalone species distribution can be roughly divided into two parts: northern and southern species.

H. discus hannai are found in the northern waters while the southern waters are the habitat for species such as Haliotis gigantea, Haliotis sieboldii, Haliotis discus, etc.

The world's commercial species include Haliotis ruber in Australia, Haliotis iris in New Zealand and Haliotis midae in South Africa. Ten species are distributed in the Pacific Coast of North America, 3 of which are commercially important. Haliotis rufescens (also known as the Red Abalone) reaches a maximum length of 30 cm. The optimum water depth for abalones is dependent on the species itself as well as on the environmental conditions of the site. Normally, abalones are found at depths up to 30 metres in the intertidal zone.

Abalones have their maximum population density at depths ranging between 3–10 metres where seaweeds, their natural food, grow abundantly.