COMMERCIAL CULTURE OF THE HARLEQUIN SHRIMP
Hymenocera picta AND OTHER ORNAMENTAL MARINE SHRIMPS
Syd Kraul
Harlequin shrimp are fairly rare in Hawaii and therefore fetch a good price ($7-10 each) to the diver or aquaculturist. After shipping, retail price can be as much as $50 or more per shrimp. Limits to commercial production are primarily market demand. With over 1,000 shrimp in stock, our distributor could only sell more than 100 shrimp per month, primarily in Asia. This market might be expanded to other areas, but it doesnt seem likely that this single species would support a business. There are also rumors that mass quantities of similar shrimp are available from Central America and Africa at greatly reduced prices.
Adult Harlequin Shrimp are long lived and docile, and spawn every 3 weeks at 25 degrees Celsius. Females produce 200-5,000 eggs per spawn, attaching them to their pleopods (abdominal plates) for incubation. The eggs, about 0.8 by 0.6mm, are red when first deposited. A few days before the female molts, the previous batch of eggs hatches out to begin the planktonic larval phase. Newly hatched larvae are 0.64mm wide and O.43mm high at the cephalothorax (head and chest), and 1.4mm long, in their naturally flexed posture (2.3mm stretched out straight). The first few days, these zoeae have close-set eyes, and do not require food. After the first larval molt, their eyes protrude on stalks, and they begin feeding on plankton. We provide them with rotifers, copepods, brine shrimp, and phytoplankton throughout their larval life. Rearing success is greatly improved when copepods are included in the larval diet, as is the case for all marine larvae we have raised. These larvae have relatively stringent water quality requirements, and are more difficult to raise than small damselfishes.
After 4-8 weeks, larvae are about 3mm long and 2mm wide, and have branched pleopods, indicating that they have reached their final (mysid) larval stage. They are now ready to settle out of the plankton, and metamorphose into benthic shrimp. The benthic transition appears to be an important determinant of final survival. Healthy batches of larvae will all survive and grow to adults. Unhealthy batches may metamorphose and begin feeding, but suffer heavy losses within a week or two. Although artificial feeds might improve the marketability of Harlequin shrimp, the only feed that has worked for us is live sea stars, preferably
Linckia spp. Harlequin shrimp were once proposed as “saviors of the reef” because they are able to eat the reef destroying Crown of Thorns starfish. In Kona, Crown-of-Thorns are the most readily available stars, so they are our primary feed.