For the past five years, our team has conducted RAS based larviculture research with Domesticated Striped Bass (DSB), Morone saxatilis, (distinct from both wild striped bass or hybrid striped bass). The principal goal was to develop tank-rearing techniques and methods to improve overall production during this early life stage through to metamorphosis (about 28 dph). Among areas of investigation include evaluation of commercial, inert microdiets as “first feeds” in 4-8 dph post-larvae.
Artemia nauplii are the most common “first feeds” for many carnivorous marine species, including DSB. These “live feeds” contain excellent amino acid and fatty acid compliments and are readily consumed by the larvae at the onset of feeding. However, the process to hatch and deliver healthy nauplii is expensive and time consuming. Numerous microdiet feed manufacturers market larval diets as “Artemia replacement diets”. Our work examined more than 15 diets from leading manufacturers and found no diets accepted by DSB larvae during the first feeding stage.
However, when presented, larvae were ATTRACTED to ALL of the diets, but just refused to ingest any of them. Interestingly, we documented that larvae did, infrequently, ingest unhatched decapsulated Artemia cysts (Fig 1). From these observations, we attempted to develop diets to mimic the size, shape and compressibility of unhatched cysts and Artemia nauplii. These efforts were challenging and only partially successful.
This presentation will review our investigations with commercial diets, discuss manufacturing strategies, compare measured shapes and textures of diets to decapsulated cysts, describe compression analysis techniques to measure and compare cysts and Artemia nauplii to feeds. We will also discuss feeding behavior related to feed movement, color, water flow and background contrast.