Aquaculture America 2020

February 9 - 12, 2020

Honolulu, Hawaii

EVALUATING MICROALGAE SPECIES EFFECT ON SURVIVAL AND FEEDING DURING EARLY LARVICULTURE FOR THREE MARINE ORNAMENTAL SPECIES

 
 
 Grace  E. Sowaske* ,  Sarah A. Hutchins , Taylor N. Lipscomb, Matthew A. DiMaggio
Tropical Aquaculture Laboratory
University of Florida
 1408 24th Street SE 
 Ruskin, FL 33570
 gracesowaske@ufl.edu

The marine aquarium hobby has grown considerably in recent decades to become a multi-billion-dollar industry. Less than 10% of commercially available marine species are cultured, while the rest are wild-caught. The global marine aquarium industry is working to improve culture practices to reduce population strain from harvest on imperiled ecosystems.  Species that spawn demersally dominate the aquaculture market due to the availability of established rearing protocols, and high relative parental care and larval survival. Pelagic spawning species usually provide no parental care and the newly hatched larvae have a small mouth gape and underdeveloped gastrointestinal system that limit their diet to copepod nauplii and other small, easily digestible zooplankton or phytoplankton. Challenges associated with these characteristics need to be addressed for production of pelagic species to become commercially viable. Species such as the Pacific Blue Tang (Paracanthurus hepatus), Melanurus Wrasse ( Halichoeres melanurus), and Yellow Wrasse (Halichoeres chrysus ) are of particular interest because of their popularity in the marine aquarium trade and lack of established rearing methods .

This study focuses on the manipulation of the culture environment by providing varying algae species , potentially resulting in unique environmental and nutritional profiles which can lead to varying survival and prey capture.  Pelagic eggs  were  collected, enumerated and stocked into 15L static tanks containing  either the control treatment,  Tisochrysis lutea, Chaetoceros muelleri ,  or Tetraselmis chuii . After three  days Parvocalanus crassirostris  nauplii (<75um) were provided  and the larvae can feed for three hours. The larvae  were then harvested, enumerated and visually inspected for ingestion of nauplii. Results suggest inclusion of the microalgae  Tisochrysis lutea during early larviculture of the Melanurus Wrasse aids  in prey capture whereas  the addition of the diatom  Chaetoceros muelleri negatively impacts larval survival (P < 0 .001). Trials conducted with Pacific Blue Tang show an increased feeding response with inclusion of  either Tisochrysis lutea  or Tetraselmis chuii (P = 0 .003). The Yellow Wrasse showed no survival or feeding advantage to the inclusion of microalgae . These results will help to shape commercial production protocols and inform decisions about feasibility of production.