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Watch here for newly published research reports in 2019. (https://www.species360.org/conservation-science)
(2019) Many species of turtles and tortoises have a low reproductive potential; they grow slowly, mature late, and lay few eggs per year. The slow reproduction coupled with high costs of maintenance of the species in captivity (including costs for food, space, electricity, veterinary care, etc.) makes breeding of many testudines unprofitable on a large commercial scale. Knowledge on the reproductive traits of a species can give a crude estimation on the biological limits, i.e. on the number of offspring that can maximally be produced. If the demand exceeds the reproductive potential, illegal laundering will become more profitable and is more likely to occur. To assess the reproductive potential of a species, some research and understanding into the species life history is necessary. Some traits that are important to consider include age at first reproduction, clutch size, life span, and inter-birth intervals. The last one is not yet included in this version.
It is important to note that the reproductive output in the wild can only give a crude measure on the reproductive output expected in captivity as these may vastly differ. Some species will not be able to reproduce in captivity at all, or the husbandry techniques needed to facilitate captive breeding may not have been developed yet, whereas some species that can easily be farmed may reproduce in much higher numbers than in the wild, due to higher growth rates, when resources are constantly available. Furthermore, the data estimated from individuals under the care of zoo and aquariums members of Species360 do not represent the maximum reproductive capacity for all species. While some species are well known to have a low reproductive capacity, other species are known to reproduce in much larger numbers within commercial settings. Therefore, we are expanding our efforts to better inform on the reproductive capacity of species being bred by commercial breeders, and we hope to have more data for the second version of this database.
The database includes all CITES listed species of turtles and tortoises (181): 31 in Appendix I, 130 in Appendix II, 29 in Appendix III, and one in Appendix I/III. We matched the CITES listed species with the IUCN Red List, of the 191 CITED listed species one is assessed as extinct in the wild (EW), 33 as critically endangered (CR), 35 as endangered (EN), 33 as Vulnerable (VU), 15 as near threatened (NT), 18 as least concern (LC), 4 as data deficient (DD) and 43 have not been evaluated (NE). However demographic data is not available for all CITES-listed species. For example, data on age at first reproduction was only available for 31% of all species (55/181), clutch size for 74% of species (133/181) and number of clutches per year for 38% (71/181) of species. Additionally, we included data on other demographic variables and the number of exports reported by the exporter in the UNEP-WCMC CITES Trade Database since the year 2005.