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Cage Culturing the Endangered Bonytail
Author(s) -
Sowka Patricia A.,
Brunkow Paul E.
Publication year - 1999
Publication title -
north american journal of aquaculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 41
eISSN - 1548-8454
pISSN - 1522-2055
DOI - 10.1577/1548-8454(1999)061<0326:ccteb>2.0.co;2
Subject(s) - stocking , biology , survivorship curve , endangered species , juvenile , predation , range (aeronautics) , fish <actinopterygii> , fishery , habitat , ecology , zoology , cancer , materials science , composite material , genetics
The bonytail Gila elegans is currently the most endangered of endemic Colorado River fishes primarily because of habitat loss and predation by introduced fishes. Captive propagation may be the only way of preventing extinction of the bonytail. We examined the effects of stocking density and initial size variability on growth and survivorship of juvenile bonytails reared in floating cages for 4 months. Three stocking densities, as well as three levels of fish size variability, were used in this experiment. We found that bonytails stocked at low and intermediate densities grew larger and had higher survivorship than those stocked at high density. We also observed that fish stocked in populations with low size variability generally grew less than fish stocked in populations with high size variability; initial size variability did not affect overall survivorship. Results of this study suggest that stocking juvenile bonytails in cages at approximately 18‐22 fish/m 3 and using individuals representing a wide range of body sizes would maximize growth and survivorship. We also offer recommendations on enclosure design.