BIOECONOMICS OF Flavobacterium columnare VACCINE POND TRIALS FOR CHANNEL CATFISH Ictalurus punctatus

The United States farm-raised catfish industry stocks channel catfish (Ictalurus punctatus) and hybrid catfish (I. punctatus, ♀ x blue catfish, I. furcatus, ♂). In recent years, this industry has had a variety of problems, both in the ponds and in the marketplace. Increased disease pressures in the last few years have come primarily from the pathogens responsible for Columnaris (Flavobacterium columnare), Enteric Septicemia (ESC, Edwardsiella ictaluri), and virulent Aeromonas hydrophila (vAh). This project is conducting pond trials using comparing channel catfish vaccinated with a live-attenuated Columnaris vaccine versus an unvaccinated channel catfish control.

Goals of the project include estimating the value of the vaccine, as well as comparing growth rates and overall survival between vaccinated and unvaccinated fish. The strategy involves a pond study of channel catfish, vaccinated through bath immersion, with routine periodic sampling to track growth. Through this project we aim to create a vaccine for the US catfish industry, that when administered, will decrease mortalities due to F. columnare.

Experimental units include ten 0.1-acre watershed ponds. Each pond includes one 0.5 hp aerator, which runs from 6pm to 8am daily. Full water quality parameters of each pond are measured weekly and dissolved oxygen is measured twice daily. Fish are fed a 32% crude protein floating pellet once daily. Feeding rates are determined weekly for individual ponds, based on the 90/7 method. For this method, a pond is fed to satiation, and then 90% of that total amount is fed to the respective pond for the following seven days. Mortalities are counted and removed daily, while ponds are refilled as needed to maintain consistent water levels.

During monthly sampling, 30 fish are collected from each pond to record length and weight for each individual. Each fish is anesthetized with MS-222, and then measured for length and weight, before being placed in a recovery tank, and then returned to their respective pond. Additional blood samples were taken from ten fish per pond, during sampling events at months one and three. The blood samples will be processed and analyzed for antibody concentrations with an ELISA (enzyme-linked immunosorbent assay).

Harvest is planned for October of 2019, and complete data results and analyze will be presented at the 2020 Aquaculture America conference.