Detailed Explanation of Key Technical Points for Abalone Breeding and Seedling Rearing

Abalone is a marine mollusk that has been ranked first among the "Eight Treasures" since ancient times, and the dishes made from it are delicious and mouthwatering. Its shell has a wide range of uses; it can not only be made into precious handicrafts, but also has certain medical value. Abalone is divided into two parts, the shell and the soft body. In the past, it was only collected from the wild, but now it can be artificially cultivated. In artificial cultivation, reproduction and seedling rearing are very important.

I. Seedling Rearing Conditions

(1) Mature parent abalone: undamaged healthy individuals with a shell length of more than 6 cm; the gonads are extremely plump in appearance, covering most of the digestive gland, with the gonads protruding beyond the shell edge, and because they are filled with sperm or egg cells, the ends become purely round.

(2) The temporary holding tank for parent abalone and the nursery tank for juvenile abalone must be darkened with plastic sheeting.

(3) Collectors: mainly made from transparent organic glass, polyethylene plastic algae plates and films, etc.

(4) Collection frames: made by tying with steel bars and wrapping with film, or made by tying with thin bamboo or wood.

II. Process Flow

Parent abalone holding - artificial induction of spawning - screening of fertilized eggs - larval collection and culture (timely thinning and separate rearing) - juvenile abalone rearing.

In abalone seedling rearing, bait is especially important and must be prepared in advance. Before larval collection, the collectors need to be pre-colonized with benthic diatoms or placed in shallow culture tanks to soak for several days, and then these collectors with attached diatoms and unicellular algae are moved into the larval culture tank to collect late veliger larvae.

During the abalone seedling rearing process, algae culture must be continuously strengthened. In addition to adding an appropriate amount of nutrients to the larval culture tank, lighting should also be enhanced to promote the reproduction rate of benthic diatoms, so that the number of benthic diatoms reproduced remains balanced with the feeding amount of larvae or juvenile abalone. For this reason, fertilizer needs to be continuously added. If the bait is basically insufficient, supplementary bait should be added after changing the water or the bait plates should be replaced to meet the larval feeding amount.

III. Disease Prevention and Control

Vibriosis symptoms: the epithelial tissue of the abalone foot sheds, and affected individuals are inactive. In severe cases, there is no response to mechanical stimulation. There are active bacteria in the blood, the body loses color, the tentacles are weak and powerless, the visceral mass shrinks, the foot retracts, and abalone from metamorphosis to 1 cm undergo persistent mortality, sometimes with mortality peaks.

Pathogen: Red abalone is prone to vibriosis when young, and the biochemical characteristics of the isolated Vibrio are close to Vibrio alginolyticus.

Timing: It is generally prone to occur under high temperature conditions or with excessive oxygenation.

Prevention: Juvenile abalone should be reared in a suitable environment, and for injured abalone, the wounds can be soaked and washed with medication.

Treatment: 1) Soak and wash with a 25-50 ppm chloramphenicol seawater solution for 0.5-1 hour, or soak and wash with a 1% seawater solution of compound sulfamethoxazole for 5 minutes. 2) Prepare a 5% seawater solution with chloramphenicol or compound sulfamethoxazole and apply it to the wounds.

All the above medication treatment methods require placing the abalone in the air for 10-15 minutes so that the medicinal solution fully penetrates the affected area, and then returning it to seawater for rearing. In addition, if necessary, repeat the treatment once the next day.