THE EFFECT OF THREE BROODSTOCK DIETS ON THE REPRODUCTIVE PRODUCTIVITY OF THE FIRE SHRIMP Lysmata debelius

The fire shrimp, Lysmata debelius, is a valued ornamental shrimp common in the marine aquarium trade. In order to minimize the collection of wild populations while meeting hobbyist demand, the development of commercial-scale aquaculture methods are needed. While culture methods have been developed to increase production efficiency through specialized larval and growout systems, the success is limited by the reproductive output of the broodstock, which stems from the adequacy of broodstock diet. This experiment compared the effects of three diets on the reproductive output of fire shrimp broodstock.

Pairs of mature fire shrimp (N=10) were held in recirculating seawater systems with stable water quality parameters and were randomly assigned one of three diet treatments. Treatment 1 was composed of a traditional marine gel diet. Treatment 2 was a frozen diet of bloodworm (Glycera dibranchiate), quahog (Mercinaria mercinaria), and bay scallop (Argopecten irradians). Treatment 3 was a fresh diet of the same ingredients as Treatment 2. Each pair was fed 0.2 g of diet four times per day.

The pairs were observed daily to assess reproductive performance: molt cycle (days), nest incubation (days), and relative egg nest size (% abdomen). Emerged larvae were enumerated to determine spawn size. From each individual, larvae (N=50) were subsampled to determine larval quality          (N=1-4 hatches per individual). Specifically, size at hatch (mm), time to yolk sack exhaustion (days), and morphological development at the time of yolk sack exhaustion (zoea stage) were determined.

Mature shrimp fed a diet of fresh seafood produced larger spawns than those fed frozen or processed diets (Fig 1A). Further, more larvae from shrimp fed a fresh diet reached zoea II stage before yolk exhaustion than larvae from shrimp fed frozen processed diets (Fig 1B).