Acclimation to captivity, predatory characteristics and production economics of tucunare, Cichla monoculus (SPIX 1831) (Pisces: Cichlidae), including polyculture with tilapia, Oreochromis niloticus (L.), in Amazonian Ecuador /
| Main Author: | |
|---|---|
| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
|
| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | Cichla monoculus, called tucunare, pavon and peacock bass in South-, Central- and North America, respectively, is a highly appreciated carnivorous/piscivorous food fish throughout its native South- and introduced Central- and North American ranges. Present source of Ecuadorean seed stock is remote and collection limited to dry season months (August, January and February). Acclimation of eggs, fry and the few fingerlings captured was successful, while adults and sub-adults did not survive transport stress. In aquarium trials with [approximately]1g tucunare, gain was highest when 0.017g tilapia were available ad libitum. Wet to wet feed conversion ratio (FCR) was 3.7-4.1. Feeding 0.032g prey decreased gain significantly (a = 0.05), but improved FCR (2.9) when presented ad libitum for 10 days. Feeding 80% and 60% of ad libitum improved FCR when fed 0.017 g prey and deteriorated FCR when feed 0.032g prey. The upper predation window boundary decreased from 12.8% of the weight of a tucunare weighing 13.3g to 5.2% for both a 104.5g and 179.0g tucunare. The lower boundary decreased from 0.4% to 0.03% of a 13.6g and 180.6g tucunare, respectively. FCR increased from 4.5 to 8.8 and daily percent body weight preyed decreased from 11.9% to 3% for tucunare weighing 16.7g and 174g, respectively. The inclusion of microencapsulated feed as an attractant affected training success to an Oregon-Moist-Pellet-type feed: 37.5% with and 8% without. Training for dry trout pellets (42% crude protein, sinking) failed. Under polyculture with tilapia in ponds, morning and afternoon pH, temperature and DO2 were 6.2, 25.2°C, 1.7mg/l and 6.7, 30.0°C, 8.0mg/l, respectively. Stocking of 1.12g and heavier tucunare into actively breeding tilapia populations showed survivals of 95.3% and 94.7% respectively, but slow tucunare growth. Computer simulations showed a negative influence of tucunare stocking on net revenues, although maximum attainable stocked tilapia average weight increased by controlling recruit biomass. Profitability depended on pond area and stocking practice. Maximum tucunare growth was not achieved: Three (46.7g) stocked informally with unfed tilapia, averaged 500g after 192 days and were actively breeding. Influence of prey visibility on growth and other pellet adaptation techniques warrant further investigation to fully exploit tucunare's growth potential. |
|---|---|
| Item Description: | Typescript (photocopy). Vita. "Major subject: Wildlife and Fisheries Sciences." |
| Physical Description: | xviii, 175 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |