MTN 5:2 More on the Tag Loss Problem

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More on the Tag Loss Problem

Stephen E. Cornelius
The University of Texas, Marine Science Institute, Port Arkansas Marine Laboratory, Port Arkansas, Texas 78373 U.S.A.

In a recent number of Wildlife Monographs (No. 52, February 1977), I came across some information that is pertinent to the tag loss problem. In this study, conducted by T.L. Riggert Department of Fisheries and Wildlife, Western Australia Wildlife Research Center, P.0. Box 5, Mullaloo Drive, Wanneroo, Western Australia 6065) considerable difficulty was encountered with corrosion of monel metal bands in hypersaline marshes. The average time the bands were legible was less than one year. Dr. Riggert was subsequently advised that titanium was the most suitable metal for saline waters of the concentrations on Rottnest Island.

In correspondence with Dr. Riggert I learned that these marshes contain saline solutions which range up to 320,000 ppm and are high in sulphides from the breaking down of organic matter. He referred me to a paper by Uhlig, H.H. 1963. Corrosion and Corrosion Control: An Introduction to Corrosion Science and Engineering, John Whitley & Sons Incorp. , New York, London, p. 371, which described monel metal as being most unsuitable in saline waters that are stagnant or contain sulphides.

According to Dr. Riggert, titanium bands have been used on Mountain Ducks now for over 70 months with no sign of wear. A paper presenting these data on band loss through wear and abrasion will be published this year. Chemical analyzation of the bands determined them to be essentially commercially pure titanium with impurities consisting of cobalt, copper, iron, nickel, and potassium each in amounts considerably lower than 1%. Further information is available from Dr. Ken Varcoe, I.M.I. Australia Ltd., Metals Technology Division, 148 Lonsdale Street, Melbourne, Victoria 3000, Australia.

It should be noted that the marshes where this study took place have a chemistry quite different than that of the ocean. Be that as it may, it appears that titanium, with its extreme hardness, yet light weight relative to other metals and resistance to abrasion and corrosion, should be considered a possible candidate to replace monel metal as the most suitable tag in marine turtle research.