Survival and Growth of Crangon nigricauda Larvae (Decapoda, Caridea) Raised on Experimental Diets

Newly hatched Crangon zoeae from different maternal shrimp were raised separately using an Imhoff cone larval-rearing system. Experimental diets were Chaetoceros gracile , live Artemia nauplii, lyophilized Arremia nauplii particles, calcium alginate microencapsulated (CAM) Artemia nauplii, lyophilized Daphnia magna and CAM Daphnia magna . A dependable "atomizer" design for lab oratory preparation of CAM diets was developed. Initially, survival rates of zoeae fed either Chaetoceros or live Artemia nauplii were evaluated in order to establish a suitable control diet for subsequent growth experiments, and the interbrood and intrabrood components of zoed survival variation were analyzed.
Crangon zoeae ate every type of food offered to them, but only Chaeroceros- fed zoeae survived to metamorphosis. Zoeal survival rates were extremely variable. Interbrood variation was greater than intrabrood variation, but the difference was not statistically significant. Zoeae from smaller maternal shrimp were generally more active and had greater survival rates than zoeae from larger, presumably older and senescent shrimp. Zoeae that were fed Chaetoceros supplemented with CAM Artemia nauplii had significantly greater ( P < 0.001) growth rates than siblings fed only Chaetoceros .
Suspension feeding on Chaetoceros was probably more efficient than raptorial feeding on Artemia nauplii, resulting in greater survival rates. Supplementing a successful microalgal diet with CAM Artemia nauplii allowed greater use of zoeal feeding mechanisms, added an animal nutrient source to the diet, and affected growth rates by increasing the molt increment and decreasing the intermolt period.