Visible Implant Elastomer Research Articles

Evaluation of visible implant elastomer tags for tagging juvenile gilthead seabream (Sparus auratus L.); effects on growth, mortality, handling time and tag loss

The use of the fluorescent visible implant elastomer (VIE) tagging system in juvenile gilthead seabream, Sparus auratus L., between 7 and 18 g was examined. Four different colours (red, green, orange and yellow), three body positions (dorsal, lateral and caudal) and two orientations (horizontal and vertical) were tested. The mean tag application time for each fish was 15.7±0.32 s. There was no mortality associated with the method of tagging. The most visible tag colour was red. Injection orientation had a significant effect on length, width, fragmentation and fluorescent intensity of the tag. Horizontal tagging is recommended because of high fluorescent intensity, low fragmentation and for double tagging. There were no differences in growth between untagged controls and the VIE-tagged fish.

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.

Visibility of Visual Implant Elastomer Tags in Atlantic Salmon Reared for Two Years in Marine Net-Pens

Abstract We evaluated detectability of visual implant elastomer (VIE) tags in individual Atlantic salmon Salmo salar reared from smolts to adults in commercial marine net-pens. A total of 9,000 individual smolts were marked (adipose eye, lower jaw, or both) with colored VIE tags. During the period from March 1998 to December 2000 (2–28 months after tagging) a total of 3,220 fish were visually inspected for VIE tags. Tag detection rates remained high (>90%) for the first 17 months after tagging but then declined sharply, particularly for VIEs in the jaw. Use of a UV light significantly increased detection of both eye and jaw VIE tags. We conclude that VIE tags are optimal for use in Atlantic salmon when recovery of fish occurs within 17 months of tagging.

Evaluation of the Use of Visible Implant Tags in Age-0 Atlantic Cod

The visible implant elastomer (VIE) tag and the soft visible implant alphanumeric (VIAlpha) tag were evaluated as methods for tagging age-0 Atlantic cod Gadus morhua. Tank experiments on laboratory-bred Atlantic cod (82–141 mm) lasted 150 d. The VIE tag proved to be a good alternative when put on the dorsal part of the fish, with no tag loss and good tag visibility. When put on the ventral part of the fish, however, many VIE tags were covered by growing silvery scales. Retention of soft VIAlpha tags injected behind the eye was quite low (67%), but larger fish had higher tag retention than smaller fish. Survival of experimental fish was high (96%). Mean specific growth rates ranged from 0.46% to 0.51% per day. Both VIE and soft VIAlpha tags were used to individually tag age-0 Atlantic cod (85–290 mm) in the wild. Skin pigmentation of wild Atlantic cod made reading soft VIAlpha tags difficult, while VIE tagging on the dorsal part of the fish still worked well. We suggest that VIE tags are a good alternative for short-term demographic studies on age-0 Atlantic cod, while low retention rates cast doubt on the use of soft VIAlpha tags on these small fish.

Evaluation of visible implant elastomer for individual marking of small perch and common bully

Visible implant elastomer (VIE) was evaluated as a method for individual marking of small perch Perca fluviatilis and common bully Gobiomorphus cotidianus to use in capture–recapture studies. Growth, survival and mark retention was measured in 25 VIE marked and 15 unmarked fish of each species during a 125 day laboratory experiment. Marking had no effect on growth or survival of either species and mark retention in perch was 100%. Common bully mark retention was high for the initial 30 days but decreased to 72% by the end of the experiment. VIE marking provided an excellent method for individual identification of small perch over periods of at least 125 days, but improvements to common bully mark retention are necessary if VIE is to be used in capture–recapture studies >30 days.

Detection of Visible Implant Elastomer in Fingerling and Yearling Rainbow Trout

Visible implant elastomer (VIE) was evaluated for marking yearling rainbow trout Oncorhynchus mykiss. The rate of tag detection after the yearlings had been at large for 35 months was also compared with the detection rate found in a subsequent year-class that had been marked as fingerlings and had been at large for 29 months. Fish were marked in the postocular adipose eyelid tissue and on the ventral surface of the lower jaw and examined in the dark under ultraviolet light. Detection rates for both year-classes ranged from 29% to 33%, based on the proportion of fish with two detectable marks. Because the marks were not easily recognized, we believe the detection rates were overestimated. We conclude that detection of VIE at the sites we chose was problematic for the strain of rainbow trout we marked. More favorable long-term detection rates in other species suggest that poor detection rates may be unique to heavily pigmented strains of rainbow trout.

The evaluation of passive integrated transponder (PIT) tags and visible implant elastomer (VIE) marks as new marking techniques for the bullhead

The evaluation of passive integrated transponder (PIT) tags and visible implant elastomer (VIE) marks as new marking techniques for the bullhead

The evaluation of passive integrated transponder (PIT) tags and visible implant elastomer (VIE) marks as new marking techniques for the bullhead

To test the reliability of PIT tags and VIE marks as new marking techniques for the bullhead Cottus gobio, different tagging treatments were assayed. The relatively high recapture rates suggest the applicability of both marking techniques for this small benthic fish species.

An Evaluation of Visible Implant Elastomer for Marking Age-0 Brown Trout

Injection of visible implant elastomer (VIE) was evaluated as a way to provide age-0 brown trout Salmo trutta with externally visible internal marks. We first tested this fluorescent elastomer material in a laboratory experiment using a single color and body position to batch-mark the fish (28.9–44.1 mm fork length). The experiment lasted for 77 d, with no mortality or tag loss and no significant (P = 0.44) effect on fish growth. Similar marks were then used to individually tag age-0 brown trout (26–70 mm) in small streams in the wild using four different colors and several body positions. The immediate mortality associated with the marking procedure was low (0.5%), and visual identification of VIE marks on recaptured individuals (169 out of 699 released; 39–83 d between release and recapture) was not difficult. We found no significant differences in mean fork length between tagged and untagged individuals captured on the same date at given sampling locations. This suggests that capture and marking had no major negative effect on fish growth (assuming that tagged and untagged individuals experienced similar conditions between sampling occasions and otherwise had comparable histories).

Evaluation of visual implant elastomer and alphanumeric internal tags as a method to identify juveniles of the freshwater crayfish, Cherax destructor

In the last few years there has been an increasing interest in using traditional animal breeding techniques to improve important traits such as growth rate in freshwater crayfish. However, a major impediment to such programs is an inability to reliably identify individuals or family groups for long periods because of the non-retention of external tags through ecdysis. Visual implant elastomer (VIE) and visual alphanumeric (VIalpha) internal tags have proven useful in identifying finfish and amphibians. We evaluated the suitability of these two internal tags as a method to identify yabby ( Cherax destructor) juveniles. Both tags proved useful in identifying juveniles between 0.1 and 4.6 g, with the VIE having the higher retention rate of the two tags (up to 92%, as opposed to 79% for the VIalpha tag). Mortality, as a direct consequence of tagging juveniles with the VIE and VIalpha tags was 13% and 11%, respectively. The ability to reliably identify C. destructor juveniles will increase the efficiency of selective breeding programs for this species by allowing individuals and family groups to be pooled in growth experiments, thereby decreasing the impact of confounding environmental effects.

Detection and Retention of Postocular Visible Implant Elastomer in Fingerling Rainbow Trout

Abstract Short-term (195-d) detectability and retention of both green and yellow visible implant elastomers (VIE) in the postocular adipose tissue of fingerling rainbow trout Oncorhynchus mykiss were examined. Both colors gradually became undetectable over 186 d of observation when a blue-filtered flashlight and amber glasses were used to aid in mark detection. However, with the use of ultraviolet light, one mark was detectable in 87% of a 60-fish sample after 195 d, and the other mark was visible in 57%. Marking skill apparently varied between personnel and probably led to the difference in detection rates between colors. The mean total length of fish with two detectable marks was 231 mm, compared with 220 mm for those with one or no detectable marks, suggesting that detectability increased with size of fish at marking.

Stocking of brown trout, Salmo trutta L.: effects of acclimatization

One‐year‐old hatchery brown trout, Salmo trutta L., (n = 16 520) from a sea‐run, local brood stock were marked and released (scatter‐planted) into the River Laisälven in northern Sweden. Eight different groups were created using Alcian blue and Visible Implant Elastomer tags. Half the fish were kept in small enclosures in four stocking areas for 6 days before release. The other half were released just after transportation. To evaluate the effect of acclimatization on post‐stocking performance, the areas were electric fished 2 months later. During the electric fishing survey, a higher number of the acclimatized hatchery fish were recaptured than those released immediately. The growth rate of stocked fish differed significantly between stocking areas and fish held in enclosures grew more than those released directly. The rate of recapture of hatchery fish varied between stocking areas (6.4–17.4%). Movements of juveniles within and between the stocking areas were low, and only 3.6% of the recaptured fish were found in an area not originally stocked. These results showed that acclimatization of fish before release increases the number and size at recapture within a stocking area.