WORLD AQUACULTURE 25 often feed near the surface, especially during dawn and dusk. Young paddlefish may have been prey for bald eagles and osprey that were observed taking catfish from these ponds. However, aside from some fish lost to incidents of low dissolved oxygen concentration, most paddlefish mortality was not observed directly. Harvesting and Holding Mature Paddlefish By fall of 2009, adult paddlefish were consolidated into one catfish pond and an effort was made to segregate them by sex into two ponds. Males were identified by the presence of breeding tubercles on the head and females by the presence of mature ova, a swollen abdomen and their larger size. Average weight was 11.3 kg for females and 9.1 kg for males at harvest. Estimated farm labor costs were $700 for final on-farm sex determination and $500 for harvesting 177 large paddlefish weighing 1919 kg. Paddlefish (177) were harvested and transported from catfish ponds in western Kentucky to two small (0.20ha) holding ponds in northern Kentucky during February 2011, where they were held until processing the following spring. Harvest of holding ponds occurred when water temperature was less than 10 °C. Holding ponds could not be seined; therefore, fish were captured with a gill net (15-cm bar mesh). This made harvesting unpredictable, particularly as the pond water temperature warmed during spring. The number of paddlefish caught per harvest was variable. Females were again tested for the presence of mature ova by inserting a capillary tube into the vent and extracting a small sample of eggs. Mature females and males were harvested and immature females were returned to the holding pond. On average, only about two hours could be spent harvesting fish, because the processing facility was located many hours away. Fish were transported live to the processing facility in a covered plastic fish box supplied with compressed oxygen gas fed through a diffuser. Processing Paddlefish Paddlefish were processed in approved fish processing facilities in central Kentucky because a more convenient location was not available in northern Kentucky. Fish (67 females and 46 males) were processed on 14 days between February and April 2011 by 2-6 people. Immature females (53) were released into lakes for future harvest. Male and female fish were filleted and roe from mature females was processed into caviar. Fish were bled and fillets were trimmed of red tissue. Fillet yield of paddlefish was 33 percent, similar to that reported by Decker et al. (1991) for fillets with skin removed. Paddlefish fillets with skin were sold fresh. Medium and up-scale restaurants in the Cincinnati, Ohio area paid an average of $12.10 per kg for 159 kg of fresh fish fillets. There was little difficulty selling fresh product at this price. Paddlefish roe totaled 47.6 kg from 67 females. Roe yield ranged between 0.59 and 1.5 kg per female with an average of 0.95 kg. Paddlefish ovaries were rubbed gently on a coarse-mesh screen to separate eggs from unwanted ovarian tissues. Eggs were rinsed and placed on a fine-mesh screen for further cleaning. Waste associated with processing roe into caviar ranged from 25-33 percent by weight. After the final rinse, eggs were salted and weighed amounts packed in steel caviar containers, which were sealed and refrigerated. Paddlefish and channel catfish in a seine. Paddlefish and members of the seine crew. (CONTINUED ON PAGE 26)
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