Cool Stories

All over the world customers of NMT Cools StoriesNorthwest Marine Technology, Inc. are using our products to discover many important and interesting facts about a variety of species.

Much of this work is critical to the survival of endangered species, and is ground breaking science, that provides information that can then be used to protect habitat.

NMT supports the great work that our customers are doing. We are often amazed and inspired by the great projects. If you have a Cool Story you would like to share please contact



>> Sea Horses Down Under

sea horsesSeahorse tagging is among the examples of the versatility of NMT's Visible Implant Elastomer.


Dr. Keith Martin-Smith, a Project Seahorse researcher based at the University of Tasmania, turned to VIE for experiments to mark and evaluate seahorse population structure and movement in the wild. Seahorses can be tagged under water, and by using a combination of tag colors and locations, Dr. Martin-Smith and his team have been able to track hundreds of individuals.


Photo courtesy of :  J. Clark-Jones, Project Seahorse.





>> Crayfish in Madagascar

Conservation and sustainable harvesting of Crayfish in Madagascar
by Julia Jones

crayfishmadagascarJulia Jones, a graduate student from the University of Cambridge, is studying the crayfish in Madagascar's eastern rainforests with the aim of developing recommendations for improving the sustainability of the very significant local exploitation and investigating the possibility of developing astaciculture.

Crayfish are not what first springs to mind when you think of Madagascar. Biologists probably first think of the lemurs, the incredible diversity of chameleons and other reptiles and possibly the fascinating plant life such as the dry spiny forests of the south, the giant Baobab trees or the lush, humid forests. Economists and sociologists may think of a different picture, of an incredibly poor country (with the 9th lowest GNP in the world) with crippling population expansion and an economy heavily dependant on subsistence farming.

However crayfish very are important both from the biological and the socio-economic point of view. There are 6 described species (with a number awaiting taxonomic determination), all belonging to an endemic genus Astacoides. They are interesting to biologists and biogeographers as there are no crayfish species native to the African mainland They also matter to the people. In areas where crayfish live (in the highlands of the south east), they represent a very significant source of income for villagers and a vital means of obtaining protein and calcium. Crayfish are recommended by local healers for pregnant women and lactating mothers, sensible advice in an area where the diet consists mostly of rice with little else. Villagers have exploited crayfish for money and food for generations and the forests have always held an ample supply. Until now that is.


>> Juvenile Maine Lobsters

Using Coded Wire Tags for Mark/Recapture Investigations of Juvenile Maine Lobsters
by Diane Cowan


Scientists at The Lobster Conservancy (TLC) are using coded wire tags to mark juvenile lobsters at three nursery areas on the Maine coast. The long-term mark/recapture studies are providing information on growth rates, seasonal migrations, and survival from year to year.

The tags are Sequential format so that the decimal code includes an "agency" code, "batch" code and individual identification. To identify a lobster that has been tagged and recaptured, the tag must be recovered and read using a dissecting microscope. Recaptured animals are then re-tagged. TLC scientists have tagged over 10,000 juvenile lobsters.  Although individual lobsters have been captured on up to seven separate occasions, most lobsters are captured only once. About 10% are captured twice.  The record length of following one individual is four years.

counting lobstertag trainingclose up lobster

>> Native Fish in Grand Canyon

Researchers Study Few Remaining Native Fish in Grand Canyon


Fisheries researchers with the U. S. Fish and Wildlife Service and Arizona Game and Fish Department, in cooperation with the U.S. Geological Surveys' Grand Canyon Monitoring and Research Center, are using elastomer tags to determine abundance, distribution, and movement of native fish in Grand Canyon.  The primary concern is to determine the abundance and movement of juvenile (<150 mm) humpback chub, which are federally endangered.  One of the largest remaining populations exists in the Grand Canyon with the primary population located in the Little Colorado River, a tributary of the Colorado River in Grand Canyon.  Researchers are also concerned with abundance and movement of other native fish such as the flannelmouth and bluehead suckers.  Elastomer tags were considered because of their success with marking small fish and because of the minimal equipment needed for the tagging.  In many cases, researchers need to helicopter in to the study site, hike to net set locations, and remain in Grand Canyon for 10 to 21 days.  Given these issues, portability of tagging gear and reliability in a remote environment was paramount.  Elastomer tagging has shown to handle these conditions well. 

Although marking just began in a preliminary study, 167 native suckers were marked, with 40 of those recaptured.  The average time a fish was at large was 8 days, but some were at large 21 days.  Tags were readily visible to the field crews throughout the study period.  In fact, one elastomer-tagged flannelmouth sucker was recaptured in the mainstem Colorado River on another fisheries survey.  These preliminary results suggest elastomer tagging can be an effective tool to mark small native fish in a remote canyon.  Researchers will continue to evaluate the effectiveness of elastomer tagging so this technique can be used in the future to tag the endangered humpback chub. 

grand canyongrand canyon

Photo= juvenile flannelmouth sucker with elastomer dye

Photo = The Little Colorado River near Grand Canyon

>> Australia's Painted Crayfish

Discovering the painted crayfish


Ashley Frisch, at James Cook University, is beginning to unlock some of the painted crayfish's secrets. His studies first required a technique to identify individuals. Ashley tested NMT's Visible Implant Elastomer and found them highly suitable.

By using a combination of tag colors and locations, he devised a system for identifying up to 30,000 individuals.

crayfish crayfish

Photos: photos courtesy of Ashley Frisch

>> Tracking Slugs in Ireland

Tracking and tagging a protected European slug!

Dr. Rory Mc Donnell and Dr. Mike Gormally

tracking slugs in ireland
Dr. Rory Mc Donnell tracking the Kerry Slug in Ireland!

Applied Ecology Unit, Centre for Environmental Science, School of Natural Sciences, National University of Ireland Galway, Ireland As far as slugs go, the Kerry Slug (scientific name: Geomalacus maculosus) is about as charismatic as they come! There are even two types – one is black and white (typical in bogs and heaths) and the other is brown and yellow (typical in woods and forests).

This spotted slug was first discovered in Co. Kerry (hence its name!), southwest Ireland over 165 years ago. Today, its global distribution remains restricted and it is only found in southwest Ireland (West Cork and Co. Kerry), Spain and Portugal. As a result it is protected under both Irish and European law.

One of the key aspects of our research was to determine the population sizes of this protected species in Ireland. For most invertebrates this would not be a problem, in that scientists could use paint to tag individuals and then estimate population size using mark-recapture! For the Kerry Slug though, tagging represented a major challenge as their slimy bodies make external tag retention near impossible! The solution...VIE tags!

Thanks to this technology designed by Northwest Marine Technology we have been able to successfully mark Kerry Slugs and as a result obtain population estimates for this species over a range of sites. Our results will consequently help the conservation of this globally important slug. Thumbs up to Northwest Marine Technology from Ireland!

For additional information on the Kerry Slug project contact Rory Mc Donnell at

kerry slug
A black and white Kerry Slug
kerry slug2
A brown and yellow Kerry Slug
kerry slug close up
A Kerry Slug marked with red VIE tags!
>> Atlantic Salmon in Northern Spain

Reversing the decline of the Atlantic salmon in Northern Spain


The Bidasoa River is the easternmost river basin flowing into the Bay of Biscay in northern Spain. The 90% of the approximately 750 km2 of the Bidasoa Basin are in the Province of Navarra (Spain), but the river mouth is actually the border between the province of Gipuzkoa in Spain and France. The main stem of the Bidasoa River is nearly 70-km-long but the dense hydrographic network in the basin accounts up to 380 km of tributaries draining a densely forested basin. Even though the Atlantic salmon is the keystone species of the Bidasoa River other migrant species such as the sea trout, eel, allis shad and sea lamprey also occur along with resident brown trout and several Iberian cyprinid species.

In the early 90's, the Government of Navarra begun a recovery project in order to reverse the decline of the Atlantic salmon population in the Bidasoa Basin. In parallel with several actions commenced to improve aquatic habitat quality (water quality, fishways, etc.), stocking of Atlantic salmon juveniles is yearly undertaken. Nowadays, stocking program consist in the introduction of 50,000–70,000 spring parr marked with adipose fin cut in June and of 30,000–35,000 autumn parr with the additional DCWT mark in late September.


>> Turtles in Australia

Turtles in Australia


So just to tell you a little bit about my project, I am researching the theory of ageing using turtles as a model species. Part of my project involved trapping gravid adult turtles and injecting them with oxytocin to induce egg laying. The eggs were collected directly from the turtles this way, rather than waiting to catch adults laying. I collect excess eggs as not all eggs will mature, so once all eggs have been hatched we release the excess hatchlings back into the system within about 2 months. This head-starting is great for the local turtle population as there is high fox predation in the area, accounting for 90%+ loss of eggs.

My project involves comparing a trade-off in resources between growth and maintenance under different environmental situations, such as reduced rainfall and increased temperatures predicted to occur in the future. I can mark the turtles I monitor over the year with notching and paint marking on the shell, however as juvenile turtles grow so fast these methods are not reliable after time. We hope that by marking the hatchlings we released with VIE, we will be able to identify what year the turtles were born. This information may be valuable in the future when doing population studies. I had envisioned being able to distinguish clutches using the implant, however the hatchlings are quite small and I was not confident with my technique, also I decided that year-marking would be sufficient.


Fiona Loudon
PhD Candidate

Native and Pest Animal Unit
School of Natural Sciences
Building K8, Room 40
Hawkesbury Campus

University of Western Sydney
Locked Bag 1797
Penrith, NSW, 2751

>> Carp in China

Stocking Naked Carp into Qinghai Lake, China


Qinghai province was named after Qinghai Lake, the largest saltwater lake in China. The people of this province represent diverse cultures, religions, and ethnicities but they are all connected to Qinghai Lake. Qinghai Lake, which in Chinese means "Green Sea", is located at about 3,200 m above sea level and has an area of approximately 4,700 km2. Its circumference is greater than 360 km. One of the lakes most valuable resources are the scale-less naked carp.

Naked carp were once plentiful in the Qinghai Lake. In 1960, the estimated biomass of naked carp in Qinghai Lake was over 230,000 tons. By 1995, that biomass had dropped to only 7,500 tons. These fish provided a significant source of food as well as being an important part of religious ritual. In the early 1960s, the water level of Qinghai Lake began to decline due largely to overuse for irrigation and livestock. Rivers that once fed the lake were diverted elsewhere, preventing naked carp from reaching their spawning grounds. In 1950, naked carp had over 100 rivers and streams into which they could spawn; now there are only eight.

The Qinghai Fishery Department then decided to use NMT's coded wire tag technology to facilitate a better understanding of naked carp growth and migration trends. In October 2003, a team of NMT's biologists returned to Qinghai Lake to help local research teams launch the Naked Carp Tagging Program.


>> Ambiguous Crayfish in Georgia

Ambiguous Crayfish in Georgia


Georgia College & State University graduate student used the Visible Implant Alpha (VIA) tags to mark a population of the Ambiguous Crayfish (Cambarus striatus) in a small wooded wetland near Milledgeville, GA during 2009.

The purpose was to investigate life history characteristics and movements of these animals. She tagged 80 individuals, but was only able to recapture 7 of them. The crayfish were captured using mist-net traps and PVC traps. We tagged 10 in the lab to look at tag retention, readability, and mortality. We had no deaths and tags stayed in and were readable after molting.



>> Ants of North Carolina

Ants of North Carolina


There have been many methods developed to track dispersed seeds, many that employ the use of magnetic tags. None, though, has been small enough to track seeds dispersed by one of nature's busiest creatures, the ant. I wanted to measure the distance that ants dispersed seeds, but I could not determine a good method to track the seeds among the thick leaf litter of the eastern temperate forests of North Carolina.

Then, Jim Rice, an associate professor and fisheries specialist at North Carolina State University, told me about the coded-wire tags used in mark-recapture experiments of fish. The tags were the perfect size to inject into the small ant-dispersed seeds using the single-shot tag injector. After the ants dispersed the seeds, I used the hand-held wand detector to find the seeds among the leaf litter. The coded wire tags allowed me to quantify the dispersal behavior of the ant, Aphaenogaster rudis, a keystone disperser of understory plants in eastern North American temperate forests.

To read more, see the following reference Canner, J.E., and M. Spence* (2010). A new technique using metal tags to track seeds short distances. Ecological Research pp. 1-4-4. doi: 10.1007/s11284-010-0761-8

Photo 1
The final result: the red flags mark all the locations that we found tagged seeds, the yellow flag marks the nest entrance that the ants originally took the seeds.

Searching the leaf litter with the handheld wand detector for tagged seeds

After detection, we removed the leaf litter at the detection and search the litter within a bin until we found the seeds or tag.
>> Tree Frogs in the Dominican Republic

Using VI Alpha Numeric Tags to Help Conserve Endangered Tree Frogs in the Dominican Republic
By Peter J. Tolson


A cooperative research effort between the Toledo Zoo and Barrick Gold/ Pueblo Viejo Dominicana Corporation biologists is using NMT visible alpha numeric tags as part of a comprehensive life history study of the Hispaniolan giant tree frog, Osteopilus vastus, the Hispaniolan yellow-lined tree frog, O. pulchrilineatus, and the Hispaniolan green tree frog, Hypsiboas heilprini, in the Dominican Republic. The researchers are injecting NMT VI alpha tags beneath the skin of the left rear leg to individually identify frogs that are part of a radio-telemetry study of home range and habitat use in the El Llegal Valley. Alpha tagging is done as part of the processing of the frog immediately after capture and takes only a couple of minutes.

The numbers are clearly visible beneath the translucent skin of the under-thigh and fluoresce strongly under UV light. In order to preserve the sharpness of the implanting needle, we grasp the skin of the thigh with a pair of Adson forceps and make a tiny cut in the skin using iris scissors. After the implantation, the incision is sealed with a drop of Meridian surgi-lock 2 oc instant tissue adhesive. The procedure is bloodless and within a few minutes the frogs are hopping back into the vegetation.

Peter J. Tolson, PhD
Director of Conservation and Research
The Toledo Zoo
P.O. Box 140130
Toledo, OH 43614-0130
Phone: (419) 385-5721 x2112
FAX: (419) 385-6924

Photo 1

>> VIE used in the Southeast for endangered fish

Visible Implant Elastomer plays a role in stock enhancement
of endangered fish.
By J.R. Shute

Conservation Fisheries has been using VIE tags on small, non-game stream fishes for more than 10 years now. This is the only tag that we have found that works well with some of the smaller species....some less than 30 mm total length. We have found the tags are well tolerated by a variety of fishes. In our case, we are tagging imperiled, often federally listed, darters, madtoms, topminnows and Cyprinids.

We are currently using these tags to track movements of propagated Conasauga logperch, Percina jenkinsi (Endangered) and propagated boulder darters, Etheostoma wapiti (Endangered). The tags are easily recognizable and can be used to distinguish different released groups by using various colors or tagging positions on the bodies of the fish. These tags have allowed us to determine whether or not we are seeing in-stream reproduction of the boulder darters (we are!).

J. R. Shute
Conservation Fisheries, Inc.

fish tags
Conasauga Logperch

Cumberland Darter