Electrochemical properties of lanthanide metals in relation to their application as shark repellents

Authors: 

McCutcheon, S.A. and Kaijura, S.M.

Year: 

2013

Journal/Publisher Name: 

Fisheries Research

Volume (Issue #): 

147

Page #s: 

47-54

Contact information: 

Biological Sciences Florida Atlantic University 777 Glades Road Boca Raton, FL 33431 kajiura@fau.edu
Summary: 

Tests with lanthanide metals were conducted to determine their potential application as a shark repellent in longline fisheries.  Six lanthanide metals were tested (cerium (Ce), neodymium (Nd), praseodymium (Pr), cerium-lanthanum mischmetal (CeLa), praseodymium neodymium metal alloy (PrNdA) and praseodymium neodymium mischmetal (PrNdM)) to quantify their voltage and compare dissolution rates in seawater. A behavioral study was used to determine their efficacy in deterring bonnethead and lemon sharks.  There were no differences in the voltages produced by the metals and their voltages decreased with distance from the samples.  Freshwater produced the greatest voltages, which decreased logarithmically as salinity increased to 10 ppt.  The metals had significantly different dissolution rates, except Nd and Pr.  The time to dissolution ranged from 15.6 hrs for PrDnA to 107.6 for CeLa (lot 2). Behavioral tests were only conducted with Nd, which was not effective in repelling either shark species.