Salinity effects on behavioural response to hypoxia in the non-native Mayan cichlid Cichlasoma urophthalmus from Florida Everglades wetlands
This study quantified the hypoxia tolerance of the Mayan cichlid Cichlasoma urophthalmus over a range of salinities. The species was very tolerant of hypoxia, using aquatic surface respiration (ASR) and buccal bubble holding when oxygen tensions dropped to <20 mmHg (c. 1·0 mg l−1) and 6 mmHg, respectively. Salinity had little effect on the hypoxia tolerance of C. urophthalmus, except that bubble holding was more frequent at the higher salinities tested. Levels of aggression were greatest at the highest salinity. The ASR thresholds of C. urophthalmus were similar to native centrarchid sunfishes from the Everglades, however, aggression levels for C. uropthalmus were markedly higher.
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aquatic surface respiration;
Document Type: Regular Paper
U. S. Geological Survey, Florida Integrated Science Center, Everglades National Park Field Station, 40001 State Road 9336, Homestead, FL 33034, U.S.A.
U. S. Geological Survey, Florida Integrated Science Center, 7920 NW 71st Street, Gainesville, FL 32653, U.S.A.
Publication date: 01 April 2009