Visible Implant Fluorescent Elastomer Research Articles

Getting old: an endangered seahorse (Hippocampus whitei) lives for up to 7 years in the wild

A long-term monitoring programme from 2005 to 2021 has allowed the assessment of age and longevity in an endangered seahorse Hippocampus whitei in the wild. Seahorses were marked using visible implant fluorescent elastomer (VIFE) which allows for individual identification. The longest period from marking to last sighting was 6 years 8 months and 17 days for a female. Using a von Bertalanffy growth function model for the species, this individual would have been approximately 7 years 7 months old on last sighting. These observations suggest that seahorses in the wild can live for over 7 years and demonstrate the benefits of using VIFE in long-term movement, population abundance and life-history studies of seahorses.

Life history and population dynamics of an endangered seahorse (Hippocampus capensis) within an artificial habitat.

Species-specific life-history information is critical for successful conservation, particularly in establishing an accurate baseline status. Obtaining such information is challenging for most species, but in particular for rare and threatened marine species. To facilitate future conservation of the endangered Knysna seahorse (Hippocampus capensis) this study aimed to determine important life-history information for this species. Visible implant fluorescent elastomer (VIFE) tags were used to mark 78 seahorses within a residential marina estate in the Knysna estuary, South Africa, in February 2018. Using a mark-resight approach, the size and movement patterns of the population and growth rate of seahorses were determined over a 14-month period. The closed population estimate for H. capensis, within Thesen Islands Marina, was estimated to be 134 (118-152 95% C.I.) in February 2018 compared to only 72 (48-108 95% C.I.) in February 2019. The species showed rapid initial growth with males and females having similar rates of growth based on the specialised von Bertalanffy growth function model. The importance of Reno mattresses as a habitat for H. capensis was confirmed based on the high abundance and site fidelity of the population, which emphasises the conservation potential of heavily modified environments for threatened seahorse species. The use of VIFE tags was deemed effective in studying this endangered seahorse and allowed the collection of important information for this species which can be used in future Red List assessments and conservation actions.

Evaluation of visible fluorescent elastomer tags implanted in marine medaka, Oryzias dancena

The aim of this study was to assess visible implant fluorescent elastomer (VIE) tagging and stress response in marine medaka, Oryzias dancena. The experimental fish were anesthetized individually and marked with red, yellow, or green elastomer at each of the following three body locations: (1) the abdomen, (2) the back, and (3) the caudal vasculature. During 12 months, the accumulated survival rates of fish in the experimental treatments were not different among red, yellow, and green elastomers. The experimental fish retained > 85% of the tags injected in the back, > 70% of the tags injected in the caudal vasculature, and > 60% of the tags injected in the abdomen (P < 0.05). An important observation was that the abdomen site was associated with poor tag retention. For all injected sites, the red and green tags were able to be detected more easily than the yellow tags when observed under both visible and UV lights. Tag readability was lower for the abdomen site than for the other sites (back and caudal vasculature). Thus, VIE tags were easy to apply to marine medaka (< 1 min per fish) and were readily visible when viewed under UV light.

Long-Distance Movements of Six Darters (Teleostei: Percidae) in the Red River, Kentucky

We compared the long-distance movements of the Frecklebelly Darter, Percina stictogaster, a pelagic fish species, to those of five other sympatric benthic or semipelagic darters. In four reaches of the Red River, Kentucky we tagged 942 individuals of six darter species using subcutaneous injections of visible implant fluorescent elastomer (VIE) from May 2012 to May 2013. These reaches, plus an additional four reaches, were surveyed by snorkeling or seining to detect previously tagged fishes. Over seven sampling sessions spanning June 2012 to November 2013 a total of 58 tagged darters were detected, including 20 P. stictogaster. Most darters were detected in the same reach in which they were tagged; inter-reach movements occurred more in pelagic (3 of 20) and semipelagic species (2 of 4) (both Percina) than in benthic species (2 of 34, all Etheostoma). Most (6 of 7) inter-reach movements were upstream. The relatively high dispersal tendencies of Percina darters suggest these darters are particularly vulnerable to in-stream barriers and that maintaining connectivity among populations should be a critical management goal.

Evaluation of a Visible Implant Fluorescent Elastomer Tag in the Greenling Hexagrammos otakii

The aim of this study was to assess visible implant fluorescent elastomer (VIE) tagging in greenling Hexagrammos otakii. The experiental fish were anesthetized individually and marked with orange, yellow, red, and green elastomer at the following five body locations, respectively: the adipose eyelid, the surface of the dorsal fin base, the inside surface of the pectoral fin base, the inside surface of the pelvic fin base, and the surface of the anal fin base. Control fish were anesthetized but not marked. During the 20-month trial, fish growth and retention, underwater visibility, and readability of the tags were determined. After 20 months, body length of marked greenling (<TEX>$43.2{\pm}3.5cm$</TEX>, mean <TEX>${\pm}$</TEX> standard deviation [SD]) did not differ from that of the control (<TEX>$41.4{\pm}3.7cm$</TEX>). Additionally, the body weight of marked greenling (<TEX>$527.4{\pm}39.8g$</TEX>, mean <TEX>${\pm}$</TEX> SD) did not differ from that of the controls (<TEX>$505.9{\pm}31.7g$</TEX>). Greenling retained >90% of the tags at the surface of the dorsal fin base. The anal fin base showed a higher tag retention rate than the inside surfaces of the pectoral fin and the pelvic fin bases (P < 0.05). Red and orange tags were identified more easily underwater than green and yellow tags. Green and yellow tags emitted fluorescence in response to a narrower range of light wavelengths. Thus, the VIE mark was easy to apply to greenling (< 1 min per fish) and was readily visible when viewed under an ultraviolet lamp.

Evaluation of a Visible Implant Fluorescent Elastomer Tag in the Soft-shelled Turtle, Pelodiscus sinensis

Survival, tag retention and tag readability were compared among the control and three treatment groups of soft-shelled turtles, Pelodiscus sinensis Crother, 2000 (mean body : ), marked with visible implant fluorescent elastomer (VIFE) tags for 16 months. Mortality 4 to 16 months after tagging was attributed to collection and handling stress rather than to the tagging itself. Tags applied to the web surface between the fourth and fifth dactyl of the hindfoot appeared to have the highest retention rates, while adipose eyelid tagging had high tag readability but a high loss rate. We conclude that in soft-shelled turtles, the most suitable region for VIFE tagging is on the web surface between the fourth and fifth dactyls of the hindfoot.

Movement pattern and home range of Roman Chrysoblephus laticeps

The movement behaviour of adult Roman Chrysoblephus laticeps (Sparidae) was investigated using mark-and-recapture techniques in the Goukamma Marine Protected Area (GMPA) and the Tsitsikamma National Park (TNP) on the South African temperate south coast. The study was designed to improve the spatial resolution of previous studies on Roman that suggested residence behaviour, but which could not estimate home range size. A combination of conventional barbed dart tags and visible implant fluorescent elastomer (VIFE) tags were used to tag Roman from a skiboat in the GMPA. Roman were tagged with dart tags from the shore in the TNP. Of the recaptures, 61% were within 50m of the tagging position, confirming that Roman are very resident. A few fish, independent of size and sex, moved distances up to 4km. A model was developed to quantify the degree of residence, by accounting for tag loss, mortality and the distribution of recovery effort. The probability of a Roman remaining within an area of 1ha is 0.91 (GMPA) and 0.94 (TNP) — such a small home range suggesting that individual Roman would benefit from small MPAs.

Anchor and Visible Implant Elastomer Tag Retention by Hatchery Rainbow Trout Stocked into an Ozark Stream

As part of a study to evaluate the stocking of rainbow trout Oncorhynchus mykiss in an Oklahoma Ozark stream, we tagged 2,542 hatchery-reared rainbow trout (123–366 mm total length) with individually numbered Floy FD-68B anchor tags and visible implant fluorescent elastomer (VIE) tags. We experimentally stocked double-marked rainbow trout into a small northeastern Oklahoma stream from November 2001 to March 2002 and resampled them monthly from December 2001 to October 2002 by electrofishing. Anchor tag retention was 91% through 6 months, and VIE tag retention was 96% through 6 months despite extensive handling of fish within 24 h of tagging. Based on the ease of application, high visibility, and high retention observed in this study, we recommend the use of VIE tags as a batch mark in similarly sized, similarly pigmented fish. The retention of VIE tags was slightly higher than that of anchor tags, and cost per fish was less for VIE than for anchor tags. However, VIE tags would have limited utility if numerous individual tags are necessary; therefore, we recommend anchor tags as individual marks in similarly sized salmonids. Retention for both tag types was relatively high and could be corrected for when estimating population parameters from tagging data.

Visible implant fluorescent elastomer tagging of the big-bellied seahorse, Hippocampus abdominalis

Wild and captive management of seahorses often requires individual or batch identification. In seahorses this has proven difficult in the past because of the seahorses’ rigid body structure, reduced size of fins and susceptibility to infection. We investigated the suitability of visible implant fluorescent elastomer (VIFE) for tagging the big-bellied seahorse, Hippocampus abdominalis, Leeson 1827. Thirty-six seahorses were tagged and their mortality, growth and tag retention assessed over a period of 7 months together with 36 control seahorses. No tagged or control animal died. In tagged animals growth rate in standard length (SL) was 6% less than untagged animals (non-significant), and growth rate in weight was 10% less than untagged animals (significant) over the experimental period. No tags were lost during the experiment. Tag visibility under LED blue light did not decline significantly although tag detection with the naked eye decreased significantly over the first month of the experiment. Our results show that VIFE is a highly effective batch tagging method for seahorses with minimal biological effects.

Evaluation of visible implant fluorescent elastomer (VIE) as a tagging technique for spiny lobsters (Jasus edwardsii)

Tagging crustaceans for growth studies is often difficult because external tags/marks may be shed or cause mortalities during moulting. In this investigation, the effectiveness of visible implant fluorescent elastomer (VIE) as an invasive tagging technique for spiny lobsters (Jasus edwardsii) was investigated over a 6-month period. Tagged lobsters were either tagged with the tag running transversely across the ventral abdominal superficial flexor muscle block (transverse VIE) in the second abdominal segment, or in-line with the ventral abdominal superficial flexor muscle block (longitudinal VIE). Non-tagged lobsters were used as the control. At the conclusion of the investigation there were no differences in growth or survival between tagged lobsters and untagged controls and tag retention rates were 100% for both tagging treatments over the 6-month period. Tag visibility was high after six months in both tagging treatments, although higher in the longitudinal VIE treatment. Tag fragmentation was frequent in the transverse VIE treatment, but infrequent in the longitudinal VIE treatment. We conclude that VIE is an effective tagging technique for J. edwardsii in terms of the high degree of tag visibility, retention, and non-detrimental impact on the growth and survival of tagged animals, provided the VIE tag is injected in-line with the orientation of the muscle fibres/tissue.

Retention and in situ detectability of visible implant fluorescent elastomer (VIFE) tags in Pagrus auratus (Sparidae)

This paper assesses the potential effectiveness of the visible implant fluorescent elastomer (VIFE) tagging system for identifying groups of snapper (Pagrus auratus: Sparidae) in the field. Retention rate after surface tagging longline‐caught fish was 93% over a 2‐week period, with no mortality attributable to tagging. Incidence of fin or scale infection did not differ between tagged and control fish. A protocol for tagging snapper underwater was also developed. This technique caused less stress to the fish than remote fishing methods, but was labour intensive when large sample sizes were required. Orange VIFE tags were visible to divers at ranges of up to 6 m in water visibility of 8–10 m, when exposed to light frequencies capable of inducing fluorescent emissions. Red, green, and yellow tags were only identifiable at shorter ranges, depending on ambient light levels and direction. The range of tag detection increased with increasing water clarity. We suggest that VIFE tagging has better retention rates and is less intrusive compared with previously employed externally readable tags. Because tags are identifiable in situ without the necessity of recapture, this method has potentially wide‐ranging applications in fish ecology and behavioural studies for adult as well as juvenile fishes.

Evaluations of Visible Implant Fluorescent Tags for Marking Coho Salmon Smolts

Abstract Groups of about 10,000 smolts of coho salmon Oncorhynchus kisutch were marked with one of two types of fluorescent tags: visible implant fluorescent filament (VIF) and visible implant fluorescent elastomer (VIE). Fish were also tagged with coded wire tags and adipose fin clipped to assess fluorescent tag retention and marine survival. Ocean recoveries were reported through the coastwide mark–recovery database. Returning fish were examined for the presence of tags, and survival and exploitation data were compared among groups. Fluorescent tags in approximately 90% of fish bearing them were easily seen in natural light. Probabilities of recovery, either in fisheries or spawning escapements after fisheries, and survival rates, did not differ significantly between coded-wire-tagged fish with and without fluorescent tags (either type). Short-term losses of fluorescent marks were about 5%; long-term losses between application and recovery were about 28% for VIE but were not statistically significant fo...

Tagging of juvenile lobsters ( Homarus gammarus (L.)) with visible implant fluorescent elastomer tags

Visible implant fluorescent elastomer (VIFE) tags were implanted beneath the epidermal layer within the abdomen of 25 juvenile lobsters. After three molts the tag retention was 100% and the total survival 92%. The results suggest that VIFE tags could be an effective tool when assessing the feasibility of enhancing natural lobster stocks.

A comparative evaluation of three methods used to tag South African linefish

Tagging effects and loss rates of 60 Roman Chrysoblephus laticeps tagged with dart tags with barbs (D-tags), T-bar filaments (T-tags) and visible implant fluorescent elastomer (VIFE) tags were investigated. The fish were tagged and monitored in a controlled tank experiment over a period of 198 days. Application technique and underwater visibility of VIFE tags were assessed in a preliminary experiment on Roman and on fransmadam Boobsoidia inornata. The use of 25-gauge needles improved VIFE tag application. Whereas VIFE tagging caused fin rot in fransmadam, it had no negative effect on Roman. VIFE tag codes could be identified underwater from a distance of 3m under ambient light. There was no significant difference in growth rates among groups of Roman with different tags and controls, but rates of tag loss were high for D-tags (53%) and T-tags (73%). Although some of the VIFE marks were incomplete, all VIFE-tagged fish were individually recognised at the end of the study. The results highlight the need to take cognisance of the high tag loss rate of conventional tags during the design of mark and recapture studies.