Aquaculture America 2024

February 18 - 21, 2024

San Antonio, Texas

OPTIMIZING EGG DISINFECTION FOR DEMSERAL SPAWNING SPECIES

Caralyn Brown* ,  Tiago A. Duarte, Lena R. Fitzgerald, Allex  N.  Gourlay,  Shubham  K.  Mathur, Ryan Rubino, Casey  A. Murray, Matthew A. DiMaggio , Andrew L. Rhyne

 

 Center for Economic and Environmental Development

 Roger Williams University

 1 Old Ferry Road

Bristol, RI 02809

cbrown711@g.rwu.edu

 



Clownfish are the most  ubiquitous marine aquarium aquaculture species.  Despite the success of the clownfish aquaculture, there is still a need to improve larva l  rearing methods due to the high variability of hatch, survival, and deformity rates. One way to improve these parameters is by disinfecting embryos just prior to hatching . D isinfecting embryos can  reduce or eliminate  bacteria, fungi, or protozoans from being transferred to the larval system.  Common disinfection treatments include hydrogen peroxide, iodine, and formalin.  This study aims to determine effective concentrations needed to  disinfect embryos and spawning substrates.

Three disinfectants  were  tested  at various concentrations on common clownfish (Amphiprion ocellaris) embryos .  Range finding experiments evaluated p ovidone iodine (1 00 ppm, 250 ppm, and 500 ppm), h ydrogen p eroxide (1,000 ppm, 5,000 ppm, and 10,000 ppm), and formalin (10 ppm, 10 0 ppm, 200 ppm), a long with  a  seawater control for each treatment .  A. ocellaris breeding pairs  were conditioned to spawn on acetyl sheets. One day before hatching (8-9 days),  the  acetyl sheet w as removed from the tank , and the  sheet was cut into four equal  groups of embryos .  Each  sheet was  exposed to  various  disinfectant  concentrations  for 5 minutes. After 5 minutes, embryos  were transferred into clean seawater  and reaffixed to  a ceramic tile for hatching. The tile was placed in 20 L of seawater in a custom  3-D printed hatching apparatus that orients the tile at a 60-degree angle and holds a wooden air diffuser to aerate the embryos (Figure 1).  The embryos were held in complete darkness to hatch overnight. The next morning,  numbers of  unhatched embryos , living hatched larvae,  and  dead hatched larvae were enumerated  to determine the percent hatch and percent survival.

Determining effective embryo disinfection methods improves larval rearing efficiency by helping to reduce  harmful microbial communities and increase hatch rate. In turn, this will help to reduce economic losses in research and production facilities rearing clownfish .