Parameters Affecting the Growth of the Estuarine Crocodile, Crocodylus-Porosus, in Captivity

Abstract

The effects of variation in diet, density and handling frequency on the growth, intake and conversion efficiency of immature Crocodylus porosus were tested under experimental conditions. The clutch of origin explained most of the variation in all variables. Only after taking clutch into account could it be concluded that diets of pork and beef were superior to fish. Significant interactions between clutch and density and clutch and handling frequency prevented analysis of these treatments: individuals from some clutches responded positively to stress, those from other clutches responded negatively. It was concluded that these clutch-related factors, whether they be genetic or environmental, must be elucidated before the effects of other treatments on crocodile growth can be determined.

Pathology of Runting in Farmed Saltwater Crocodiles (Crocodylus porosus) in Australia

“…26,33,48,58 However, future crocodile runts are not identifiable at hatching, since body size at hatching is a poor predictor of posthatching growth. 26,34,38,69 There is limited information on diseases and pathology exhibited by runt crocodiles. A few studies mention bacteremia, mycotic dermatitis, 64 22 There has been no in-depth pathological investigation comparing runt crocodiles with their normal counterparts from the same cohort and raised under identical conditions.…”

“…3,64 Poor growth has been found to be clutch related in that some clutches produce relatively high numbers of runts. 26,33,48,58 However, future crocodile runts are not identifiable at hatching, since body size at hatching is a poor predictor of posthatching growth. 26,34,38,69 There is limited information on diseases and pathology exhibited by runt crocodiles.…”

“…Proposed factors associated with runting include egg incubation conditions; 38,69 poor yolk absorption posthatching; 22,32 inappropriate diet or problems with diet assimilation; 11,22,26,55 posthatching environment, including temperature, stocking density, and behavior of conspecifics; 26,32,39,48,58 and failure to adapt to the captive environment.…”

“…Although various possibilities have been proposed, none have been thoroughly investigated. Proposed factors associated with runting include egg incubation conditions; 38,69 poor yolk absorption posthatching; 22,32 inappropriate diet or problems with diet assimilation; 11,22,26,55 posthatching environment, including temperature, stocking density, and behavior of conspecifics; 26,32,39,48,58 and failure to adapt to the captive environment. 3,64 Poor growth has been found to be clutch related in that some clutches produce relatively high numbers of runts.…”

Cranial sexual discrimination in hatchling broad-snouted caiman (Caiman latirostris)

“…Although clutch-effects are usually relevant for crocodilians (GARNET & MURRAY, 1986), they could not be evaluated in the present study because clutches were not equally distributed among the distinct incubation treatments (Tab. I).…”