seaturtle.org : MTN : ARCHIVES : Sign In

Among the challenges to successful deployment of satellite transmitters and other telemetry packages are the attachment process itself and adequate restraint of the turtle during attachment, which I address herein. For very small turtles a simple plastic tray may suffice to restrain the turtle. But for larger hard-shelled sea turtles, a common restraint method often involves the use of a large wooden box, frequently constructed of robust marine plywood panels that interlock or hinge so that the box may be collapsed and moved (e.g., Balazs et al. 1996). However, these boxes are often large, heavy and impractical to move around other than in large vehicles or on trailers. Smaller units have been moved on ATVs.

For a recent project tracking hawksbills in the Arabian Gulf I designed a lightweight, stainless steel low-cost collapsible restraint box to address the needs of a multi-country project that required frequent movement of gear and tagging supplies by commercial air travel. Here I present the design plans for a restraint box that has been successfully used over three years and across four countries (Fig. 1).

Figure 1. Schematic layout of side and end panels. Dotted lines = fold lines to provide structural rigidity. End schematic panels (right) are not to scale, to provide a clear view of the required folds. Two of each panel are needed to construct the box. Side panels are cut 74 cm long and folded with two 1-cm folds at 90° to each other at the top and bottom, producing a 70-cm high panel. End panels are cut 61 cm wide and are folded with 3-cm 90° spines at each side of the panel. The clasps and receiving clasp hooks must be set 5 cm from the top and bottom edges of the side panels, so that panels are interchangeable.

The restraint box was constructed of four panels of 0.15 cm thick 316-grade stainless steel with the following original dimensions: two longer side panels measuring 74 x 75 cm, and two shorter end panels measuring 70 x 61 cm. The two longer panels were reinforced through a 1-cm x 1-cm fold at the top and at the bottom to provide rigidity (Fig. 2A), while the end panels were folded down the sides resulting in two 3-cm-wide spines (Fig. 2B). The folded ends were trimmed to fit inside the folds on the longer panels interlocking each of the corners. All cutting and folding of the box panels should be done in machine shop with proper cutting and folding tools. The panels were joined together using high pressure 316 stainless steel cabinet draw latches (Fig. 2B) affixed 5 cm from the top and bottom of each joint using pressure rivets. Clasps were affixed to the longer side panels while locking pins were attached to the matching points on the end panels. An internal 90° 1 cm x 10 cm support was installed on the inside of the shorter ends coincident with the location of the latches to prevent the latches from opening when the turtle moved inside the box (Fig. 2C). The final size of the panels and effective size of the restraint box following strengthening folds was 75 cm long x 55 cm wide x 70 cm high (Fig. 2D).

Figure 2. (A) Detail of folded top and bottom edges of longer side panels; (B) folds and stainless steel cabinet latches affixed using pressure rivets; (C) internal support brace to prevent latches from popping open; and, (D) two assembled boxes on the beach in Qatar in 2010.

The overall weight of each box was 10 kg including a nylon carry bag, and the total costs of materials and workshop manufacture were approximately US$100 per box. These boxes were transported on several commercial airliners, in vehicles, on the backs of ATV motorcycles, in small boats, and by hand over various terrains. The stainless steel metal was impervious to salty conditions and allowed some small movement of the turtle while restrained, but did not break or irreversibly bend the metal sheets. Care must be taken to make all latches a standard 5 cm from the top and bottom so that all panels are interchangeable and may be used upside down or right side up.

A possible future improvement would be the provision of a series of 5 cm diameter holes close to the top to provide additional ventilation. These restraint boxes were designed for use with adult hawksbill turtles, but likely could also be used with the other smaller species of sea turtles. Most adult hawksbill turtles from the gulf region fit easily in the boxes with 5-10 cm of free space longitudinally. For larger hard-shelled species, it is possible that slightly thicker stainless steel and additional reinforcing ribs might be sufficient to restrain the turtles. I believe 10 cm longer and 10 cm wider panels with two 2 cm X 2 cm 90° angled ribs spot-welded down the length of each side would suffice to restrain larger animals. It is unlikely these boxes would be sufficiently strong to restrain leatherbacks. As they are described here, the boxes fold down to a package 75 cm long X 70 cm tall X 10 cm deep, and may be easily carried in a custom-built nylon bag. No airline classified the packed boxes as oversized baggage.

Acknowledgements: This box was designed and created for a joint project between the Marine Research Foundation and the Emirates Wildlife Society/WWF in the United Arab Emirates tracking hawksbills to elucidate habitat use patterns. This project was funded entirely by EWS/WWF. I am grateful to Lisa Perry and Marina Antonopoulou for their friendship and assistance, and thoughtful comments on the box design.

BALAZS, G.H., R.K. MIYA & S.C. BEAVER. 1996. Procedures to attach a satellite transmitter to the carapace of an adult green turtle, Chelonia mydas. In: J.A. Keinath, D.E. Barnard, J.A. Musick & B.A. Bell (Compilers). Proceedings of the 15th Annual Symposium on Sea Turtle Biology and Conservation, U.S. Dept. of Commerce NOAA Tech Memo NMFS-SEFSC-387: 21-26.

COYNE, M.S. & B.J. GODLEY. 2005. Satellite Tracking and Analysis Tool (STAT): an integrated system for archiving, analyzing and mapping animal tracking data. Marine Ecology Progress Series 301: 1–7.

GODLEY, B.J., J.M. BLUMENTHAL, A.C. BRODERICK, M.S. COYNE, M.H. GODFREY, L.A. HAWKES & M.J. WITT. 2008. Satellite tracking of sea turtles: Where have we been and where do we go next? Endangered Species Research 4: 3-22.

HAZEN, E.L., S.M. MAXWELL, H. BAILEY, S.J. BOGRAD, M. HAMANN, P. GASPAR, B.J. GODLEY & G.L. SHILLINGER. 2012. Ontogeny in marine tagging and tracking science: technologies and data gaps. Marine Ecology Progress Series 457: 221-240.

KOBAYASHI, D.R., J.J. POLOVINA, D.M. PARKER, N. KAMEZAKI, I-JIUNN CHENG, I. UCHIDA, P.H. DUTTON & G.H. BALAZS. 2008. Pelagic habitat characterization of loggerhead sea turtles, Caretta caretta, in the North Pacific Ocean (1997–2006): Insights from satellite tag tracking and remotely sensed data. Journal of Experimental Marine Biology and Ecology 356: 96–114.