In two previous articles published in Animal News I have taken a look at some of the larger (30cm and bigger) freshwater turtles in terms of their natural history and status in captivity both within the U.K. and rest of the world. Amongst the species considered were species chosen either because I have personal experience of the species (in most cases maintaining these animals for many years within the collection I share with my partner Amanda) or because they represent species that I would desperately wish to have experience with and knowledge of which I believe would be greatly enhanced by having a greater captive representation. Examples amongst the former category would be Anderson’s Flap-shelled Turtle (Lissemys punctata andersoni), Bornean Painted River Turtles (Callagur borneoensis) and Malaysian Giant Turtle (Orlitia borneensis). Examples of the latter category include the Asian Giant Softshell Turtle (Pelochelys bibroni), the Narrow-headed Softshell Turtle (Chitra indica) and the Spotted Pond Turtle (Geoclemys hamiltonii).
In this final installment I shall address husbandry and captive care requirements in general and giving some specific regimes that I adhere to in the keeping of species like the Bornean Painted River Turtle. By necessity much of the advice will be generic since a more detailed consideration would require the best part of a book.
Keepers in the U.K. with its unreliable climate and cool winters are, in terms of large turtle maintenance, almost obligated to housing their animals permanently indoors. Having said this, however, there are a few species such as the Alligator Snapping Turtle (Macroclemys temminckii) and the Chinese Softshell Turtle (Pelodiscus sinensis) which can be usefully maintained in outdoor enclosures during the warmest months of the year – at least in southern England. Opportunities for successful captive reproduction certainly increase with such species having access to outdoor ponds and natural surrounding vegetation, should we have a hot summer.
Three species could be candidates – taking appropriate precautions – for housing on a permanent basis outdoors in southern England and possibly elsewhere in England and Wales. These three species all live across a vast range in the U.S. including the north, with populations of two species extending into southern Canada. Captive stock originating from these more northerly climes are especially suitable for housing outdoors in the U.K. The three species are the Common Snapping Turtle (Chelydra serpentina), the Smooth Softshell Turtle (Apalone mutica) and the Spiny Softshell Turtle (Apalone spinifera).
One problem of outside maintenance in the U.K. is that although species like the Common Snapping Turtle regularly experience winters much colder in Canada and the northern U.S. than anything they are likely to experience in the U.K. our summers do not ordinarily hit the months of sustained high temperatures seen in North American summers. This can make breeding outside in the U.K. somewhat problematic in years with cooler summers, unless eggs are quickly located and transferred to an incubator.
All the other larger freshwater turtles will, realistically, need to be accommodated in indoor quarters. Some species such as the Fly River or Pig-nosed Turtle (Carettochelys insculpta) are almost entirely aquatic and for these a large indoor pond together with a limited space for hauling-out and basking (which may well never be utilised) represents perfectly satisfactory long-term accommodation. Obviously, when full-sized and of a potential breeding age, such species will need access to a more substantive haul-out area in the form of a sandy bank in order to facilitate egg-laying. For species of a slightly less aquatic inclination a large pond but with floating basking sites and a larger land area will be required. It is considerations such as these that necessitate would-be keepers acquiring a strong understanding of the natural history of the species they wish to keep before making any acquisitions.
The largest possible ponds should be chosen to house the larger turtle species and these need to be securely mounted and supported in order to prevent splits and ruptures. Although many specimens will feed well and grow in smaller enclosures any such accommodation should be viewed as usable only on a temporary basis. Some keepers prefer to house the young of larger turtle species in small indoor ponds, plastic storage units, etc. and move the animals on to larger accommodation as the animals themselves increase in size. This is certainly a perfectly acceptable husbandry technique, although my personal preference is to, wherever possible, accommodate even smaller individuals in the larger ponds in which they will spend their adult lives.
Décor within the pond, rocks, logs, floating oak cork bark, etc. is preferable but rough sharp edges should be avoided both to protect the pond and the turtles (especially the soft-shelled species) from physical damage. The pond should not be so clustered as to cut-down on free-swimming space. The use of aquatic plants is largely dependent upon the diet of the turtles and their size and activity. Hence, large and active species are likely to destroy any aquatic plants within a short space of time whilst less boisterous species – even giants like Alligator Snapping Turtles – will often leave plants relatively intact. Clearly – other than as a provision within the diet – it is pointless supplying decorative aquatic plants to largely herbivorous species such as Callagur borneoensis or the Yellow-spotted Amazon River Turtle (Podocnemis unifilis).
Although smaller internal filters may be utilised in small ponds containing young turtles, for larger ponds containing bigger specimens it is advisable to use a good-sized external filtration system. This is especially valid given the fact that these turtles are usually gross feeders, producing large quantities of uneaten food and faecal material. Although outside the scope of this article it is well worthwhile potential keepers familiarising themselves with optimal filtration techniques. In our largest ponds we use external filters designed to cope with twice the water volume actually present in order to account for the greater amount of waste produced by turtles compared with the likes of koi carp. We also use the likes of charcoal and other cleansing agents as an integral part of the filtration system.
Designed well, feedback from the filtration system will supply a degree of agitation within the pond water this being essential in supplying better-oxygenated waters. Supplementary air stones can also be incorporated into the pond system. The amount of surface agitation should be adjusted to fit with the typical lifestyle of the particular turtle species, since some have a marked preference for slow-moving waters – in some cases almost static.
Water quality is important in good turtle maintenance and the use of activated charcoal and zeolite within the filtration chambers can be very useful in ensuring optimal water quality. We choose to add a product called Stress Coat (produced mainly for koi carp and other fish) to the water whenever any of our turtles get a shell abrasion, mating bite, etc., since this seems very effective at preventing secondary infection and enhancing rapid shell restoration. Even with the most impressive filtration systems it is advisable to undertake regular 25-40% water changes using rainwater or matured tap water. For some of the large freshwater turtles – primarily those resident in the Amazon Basin – it is very useful to keep the water pH at slightly acidic (6.5 or so) and very soft. This can be done, amongst other means, by using proprietary chemicals purchased from aquatic stores, use of bags filled with peat or the additional of dilute tea (without the milk and sugar!) to the water. There are purpose-made formulations – usually referred to as ‘blackwater’ solutions or additives which can be purchased to mimic the Amazon river systems of a blackwater nature (i.e. with high concentrations of tannins) which, though made for fish systems are very effective for turtles residing in such river systems – including several of the Podocnemis Spp. From South America.
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