Growth, maximum daily ration and intraspecific cohabitation of the moray Gymnothorax polyuranodon (Muraenidae) in a freshwater aquarium

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Author(s)
Ebner, Brendan
Griffith University Author(s)
Year published
2017
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Some predominantly marine fish families include a small proportion of species that are obligate
freshwater inhabitants, and there is accumulating evidence for obligate freshwater species within the family
Muraenidae. Whether the muraenid Gymnothorax polyuranodon (Bleeker, 1854) can survive, grow and coexist
over an extended period in captive freshwater conditions was tested following repeated observations of this
species in freshwater streams of the Australian Wet Tropics. Changes in the body size of four individuals held
in a 1200 litre freshwater aquarium revealed that yearly growth ranged from a minimum of 21.0 cm total ...
View more >Some predominantly marine fish families include a small proportion of species that are obligate freshwater inhabitants, and there is accumulating evidence for obligate freshwater species within the family Muraenidae. Whether the muraenid Gymnothorax polyuranodon (Bleeker, 1854) can survive, grow and coexist over an extended period in captive freshwater conditions was tested following repeated observations of this species in freshwater streams of the Australian Wet Tropics. Changes in the body size of four individuals held in a 1200 litre freshwater aquarium revealed that yearly growth ranged from a minimum of 21.0 cm total length (TL) and 2.4 times body mass to 26.5 cm TL and 3.9 times body mass. Maximum daily ration of individuals (fed worms, prawns and fish) ranged from 3.4% to 3.9% of body mass. Individuals coexisted peacefully, with only brief bouts of intraspecific aggression that included biting. While the full life cycle of G. polyuranodon remains unresolved, the current study reinforces field observations and microchemistry insights indicating that this species can occupy and grow in freshwater ecosystems, and points toward the likelihood that the species probably plays an important and previously unrecognised mesopredatory role.
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View more >Some predominantly marine fish families include a small proportion of species that are obligate freshwater inhabitants, and there is accumulating evidence for obligate freshwater species within the family Muraenidae. Whether the muraenid Gymnothorax polyuranodon (Bleeker, 1854) can survive, grow and coexist over an extended period in captive freshwater conditions was tested following repeated observations of this species in freshwater streams of the Australian Wet Tropics. Changes in the body size of four individuals held in a 1200 litre freshwater aquarium revealed that yearly growth ranged from a minimum of 21.0 cm total length (TL) and 2.4 times body mass to 26.5 cm TL and 3.9 times body mass. Maximum daily ration of individuals (fed worms, prawns and fish) ranged from 3.4% to 3.9% of body mass. Individuals coexisted peacefully, with only brief bouts of intraspecific aggression that included biting. While the full life cycle of G. polyuranodon remains unresolved, the current study reinforces field observations and microchemistry insights indicating that this species can occupy and grow in freshwater ecosystems, and points toward the likelihood that the species probably plays an important and previously unrecognised mesopredatory role.
View less >
Journal Title
Cybium
Volume
41
Issue
2
Publisher URI
Copyright Statement
© 2017 Cybium. The attached file is reproduced here in accordance with the copyright policy of the publisher. Please refer to the journal's website for access to the definitive, published version.
Subject
Fisheries Sciences not elsewhere classified
Zoology
Fisheries Sciences