Another great application of fluorescence in marine research! Researchers often need a way of tagging individual animals so they can better study their ecology and behavior. One method is the use of Visible Implant Elastomer (VIE), a biocompatible material that can be injected beneath transparent or translucent tissue and remain externally visible. VIE tags are widely used for marking a broad range of fish, crustaceans, reptiles, and amphibians. VIE is made by Northwest Marine Technology, and there are both fluorescent and non-fluorescent versions. Take a look at their website to learn more and to see photos of tagged critters.
A group from the University of Sydney led by Aline Martinez recently published a paper on their investigation of methods for marking a small starfish, Parvulastra exigua (nice picture here). And they really mean small – less than 2 cm across! They injected tiny amounts (just 4 microliters) of fluorescent VIE to make each small (about 1mm) indicator spot. The number and placement of the spots on each starfish were done in a pattern so that they could identify individuals throughout the 30-day experiment. The researchers compared the VIE method against branding with a soldering iron.
For finding the fluorescent tags and identifying each individual they compared a 21-LED UV light against the NIGHTSEA FL-1. The results were clear:
According to the publication, the NIGHTSEA light ‘facilitated location of tagged animals in the field even during bright, sunny days’.
For more information contact NIGHTSEA.
Martinez, A. S., M. Byrne, and R.A. Coleman, 2013. Unique tagging of small echinoderms: A case study using the cushion star Parvulastra exigua. Methods in Ecology and Evolution, 4(10): 993-1000. DOI: 10.1111/2041-210X.12099. Read the abstract