ESTABLISHING A LENGTH-WEIGHT RELATIONSHIP FOR POST-METAMORPHOSIS JUVENILE OSCELLARIS CLOWNFISH Amphiprion ocellaris  

Philip J. Iovino*, Travis G. Knorr, and Michelle L. Walsh
 
Florida Keys Community College
Key West, FL 33040
philip.iovino@fkcc.edu

The Tropical Ornamental Mariculture Technician Program at Florida Keys Community College focuses on rearing clownfish, including the Ocellaris clownfish Amphiprion ocellaris, as model species for providing technician-level marine aquaculture skills to students. As our stock of successfully-reared clownfish juveniles increases, so does our interest in using these offspring in experimental studies, for example studies regarding feeding and stocking, which may influence the degree of our continued success.  Conducting growth studies over time, particularly if the design requires repeated measures of experimental fish, can be difficult, as handling fish for measurement can cause behavioral interruption during the experimental process (at best) or death (at worst). We wanted to document the length-weight relationship for post-metamorphosis juveniles so that we could subsequently use lengths measured via image analysis to establish feeding regimes based on body-weight per day, as well as longitudinal growth measures, without inflicting the stress of repeatedly handling fish.

We measured 52 post-metamorphosis juvenile Ocellaris clownfish (16−43 mm; 0.1−1.75 g). Fish were first anesthetized in a 10-15 ppm clove oil bath. Total lengths were measured with digital calipers (to the 0.01 mm) and weights were measured to the 0.001 g using a digital balance. The best fit (least squares) of the data followed a second order polynomial (quadratic) curve with a R2 value of over 99%.

This length-weight relationship will allow us to extrapolate weight measures from fish lengths that we can less intrusively gather via images taken through our translucent tanks.