Red-eared terrapin: Direct removal of adults

Overall effectiveness category Likely to be beneficial
Number of studies: 2
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How is the evidence assessed?

Effectiveness
40%
Certainty
50%
Harms
not assessed

Calculating overall effectiveness category

Background information and definitions

Direct removal of adults by trapping, netting, shooting, or hand capture, may offer a tool for localised eradication, particularly in England, UK where there are no known instances of successful reproduction in the wild.

A variety of traps are referenced in the literature. For example, a fact sheet on the red-eared terrapin Trachemys scripta references successful use of floating boards with baited cages on top by terrapins as basking sites. Trap preference is sometimes determined by the level of visibility to the public in addition to efficacy (Bringsøe 2006). An information bulletin references that in Australia, funnelled ‘Cathedral traps’ are used in preference to ‘basking traps’ which are difficult to transport and unsuitable for use in public or high visibility locations (O’Keefe 2009). Some studies have researched the impact of bait location on trap success. For example, a replicated field study in the USA researched bait location and found no significant difference in trapping rate between traps with bait suspended near the funnel entrance, and traps with bait filled containers (Nall & Thomas 2009).

No studies have been found that reference successful local eradication using trapping or netting techniques.

Bringsøe H. (2006) Trachemys scripta. NOBANIS – Invasive Alien Species Fact Sheet. European Network on Invasive Alien Species, 13pp.

Nall I. & Thomas R. (2009). Does method of bait presentation within funnel traps influence capture rates of semi-aquatic turtles? Herpetological Conservation and Biology 42, 161-163.

O’Keefe S. (2009) The Practicalities of Eradicating Red-eared Slider Turtles (Trachemys scripta elegans). Aliens: The Invasive Species Bulletin. Newsletter of the IUCN/SSC Invasive Species Specialist Group. 28, 19-24.

Study locations

Key messages

A replicated field study in Spain found that Aranzadi turtle traps were effective in trapping red-eared terrapins from a river but did not eradicate the population.
A study in the British Virgin Islands found that using sein nets to trap adults and juveniles was not successful in eradicating the population.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated field study conducted in 2008, in the Arga River, Spain (Valdeón et al. 2010) found that modified Aranzadi turtle traps were effective at trapping red-eared terrapin Trachemys scripta elegans and Trachemys scripta scripta but did not eradicate the populations, and that these traps performed better than modified Bolue traps, and fish-baited traps, which trapped very few terrapins. The modified Aranzadi turtle traps caught an average of 70% of observed terrapins. During five months of spring and summer 2008, one of each of the three trap types was set in each of two areas of the Arga River, Spain. On separate dates, one of each trap type was also set in 11 different water bodies. The baited traps were visited on consecutive days, while basking traps were checked weekly during five months of spring and summer of 2008.
Study and other actions tested
Referenced paper
Valdeón A., Crespo-Diaz A., Egaña-Callejo A. & Gosá A. (2010) Update of the pond slider Trachemys scripta (Schoepff, 1792) records in Navarre (northern Spain), and presentation of the Aranzadi Turtle Trap for its population control. Aquatic Invasions, 5, 297-302.
A study in 2003 in a pond at botanic gardens in Tortola, British Virgin Islands (Perry et al. 2007) found that using sein nets to trap red-eared terrapin Trachemys scripta adults and juveniles was not successful in eradicating the population. Twelve adults and approximately twenty juveniles were removed. Additional capture efforts removed further adults and juveniles in July and October 2004. Experimental methods were not available.
Study and other actions tested
Referenced paper
Perry G., Owen J.L., Petrovic C., Lazell J. & Egelhoff J. (2007) The red-eared slider, Trachemys scripta elegans, in the British Virgin Islands. Applied Herpetology, 4, 88-89.

Please cite as:

Aldridge, D., Ockendon, N., Rocha, R., Smith, R.K. & Sutherland, W.J. (2020) Some Aspects of Control of Freshwater Invasive Species. Pages 555-87 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Control of Freshwater Invasive Species

Related Actions

Actions	Effectiveness	Studies	Category
Red-eared terrapin: Biological control using native predators Action Link	No evidence found (no assessment)	0	Synopsis Link
Red-eared terrapin: Search and removal using sniffer dogs Action Link	No evidence found (no assessment)	0	Synopsis Link
Red-eared terrapin: Application of a biocide Action Link	Unlikely to be beneficial	1	Synopsis Link