Chilean Sea Urchin Essay

Chilean sea urchin, Loxechinus albus

Introduction: The Chilean Sea urchins Loxechinus albus (Molina, 1782) is an edible echinoderm animal of the family Parechinidae. This species is native to the coasts of Chile and Peru and is considered among the key benthic herbivores in Chilean coastal waters. It is harvested commercially by fishermen and is considered an ingredient in Chilean cuisine. It is also known as “common green sea urchin” and its local name in Chile is “Erizo rojo” which means “red urchin”. They can grow up to 100 mm in diameter or more. It takes eight years for Chilean sea urchins to reach commercial size. The industrial catches and over-exploitation of the animal for canned gonads has caused the extinction of many local populations.

Distribution and

The average egg size ranges from 120 – 130 um in diameters.

Because of the short longevity of the sperm (about 30 minutes), the sperm is obtained shortly before fertilization. It is recommended to select the best quality sperm –based on motility and number- via microscopic examination using Sedwegick and Neubauer chambers.

Fertilization: Washed eggs are transferred into containers of 10-12 liters whereas about a million ovules are placed in 1-um filtered and UV-irradiated seawater and at 17 – 18 °C.

Fertilization is carried out by adding one ml of sperm solution with approx. 100x106 sperms to the mentioned ovules (1 million) which means a ratio of 100 sperms to each ovule. The sperm solution has 1 ml of concentrate of sperms obtained directly from the gonad of the sea urchins and diluted in a volume of 200 ml. The success of fertilization as well as embryonic development is determined through microscopic examination. After 30 minutes the fertilization, fertilized eggs (embryos) are poured out whereas one-half of the water is changed with fresh, 0.5 um-filtered and UV irradiated seawater at 17-18