The use of archived tags in retrospective genetic analysis of fish

Collections of historical tissue samples from fish (e.g. scales and otoliths) stored in museums and fisheries institutions are precious sources of DNA for conducting retrospective genetic analysis. However, in some cases, only external tags used for documentation of spatial dynamics of fish populations have been preserved. Here, we test the usefulness of fish tags as a source of DNA for genetic analysis. We extract DNA from historical tags from cod collected in Greenlandic waters between 1950 and 1968. We show that the quantity and quality of DNA recovered from tags is comparable to DNA from archived otoliths from the same individuals. Surprisingly, levels of cross‐contamination do not seem to be significantly higher in DNA from external (tag) than internal (otolith) sources. Our study therefore demonstrates that historical tags can be a highly valuable source of DNA for retrospective genetic analysis of fish.     

Tag retention and mortality of adult Atlantic salmon Salmo salar gastrically tagged with different sized telemetry transmitters

A batch of 1 sea winter pre‐spawning adult Salmo salar from the Bush river in Northern Ireland, U.K., were gastrically tagged with large (13 mm diameter) and small (9 mm diameter) dummy acoustic telemetry tags alongside untagged control fish. Survival differed between control and tagged fish and the estimated probability of survival by the end of the study for control fish with no tag was 0·94, small tags was 0·90 and large tags was 0·72. Tag loss through regurgitation was slightly higher for fish tagged with larger tags than for fish tagged with smaller tags and the estimated probability of tag loss for fish with a small tag was 0·10 and for large tags was 0·14.     

Capture-recapture studies using radio telemetry with premature radio-tag failure

Radio tags, because of their high detectability, are often used in capture-recapture studies. A key assumption is that radio tags do not cease functioning during the study. Radio-tag failure before the end of a study can lead to underestimates of survival rates. We develop a model to incorporate secondary radio-tag failure data. This model was applied to chinook smolts (Oncorhynchus tshawytscha) on the Columbia River, Washington. Estimates of fish survival from this model were much larger than those from the standard Cormack-Jolly-Seber analysis.     

Stock identification of the sciaenid fish Micropogonias undulatus in the western North Atlantic Ocean using parasites as biological tags

Proper fisheries management of the Atlantic croaker Micropogonias undulatus is necessary in the United States due to the commercial and recreational importance of this fish species. Croaker stock structure in the western North Atlantic has been investigated in the past by various authors, with inconclusive results. In this study, macroparasites were used as biological tags to identify putative croaker stocks in the area between New Jersey and Florida, which encompasses the Mid Atlantic Bight and the South Atlantic Bight separated at Cape Hatteras, North Carolina. The macroparasite community of the fish was identified, showing the presence of 30 species in four phyla, of which several were new host records, and one species, a monogenean, was new to science. A canonical correspondence analysis was applied to determine the variables responsible for parasite species composition, to resolve the question of croaker stock structure in the western North Atlantic Ocean. This analysis showed that latitude was the deciding variable delineating the parasite community composition of the Atlantic croaker. Among the 30 parasites, 15 were identified as putative tags according to qualitative criteria, and then 10 out of those 15 were selected as being appropriate tags using quantitative criteria. These parasite tags support the presence of two stocks roughly separated at the known biogeographical barrier at Cape Hatteras.     

Validation of scale‐age determination in European grayling Thymallus thymallus using tag‐recapture analysis

To validate age determination from scales in European grayling Thymallus thymallus, the scale‐read age of fish was compared with the true age obtained by tag‐recapture analysis. A total of 3997 individuals were tagged with visible implant tags and passive integrated transponder (PIT) tags in the River Wylye, south‐west England during 1999–2007. Annual repeat surveys were undertaken and collected scales read without prior knowledge of tag‐recapture age. Accuracy of fish ageing by scales was highest in 1 and 2 year‐old fish but decreased in older fish. In later life stages (>4 years old), underestimation of age occurred and the error in reading scales rose to 51·9% in 5 year‐old fish. Age assigned from scales underestimated the tag‐recapture assigned age by as much as 3 years. This study suggests that use of scales is an appropriate method to age a short‐lived population of T. thymallus inhabiting productive lotic systems. The underestimation of age in older fish, however, needs to be considered in the management of fish stocks because it may lead to undesirable exploitation of population.     

Physiological responses of Pacific halibut, <Emphasis Type="Italic">Hippoglossus stenolepis</Emphasis>, to intracoelomic implantation of electronic archival tags,with a review of tag implantation techniques employed in flatfishes

Management of Pacific halibut (Hippoglossus stenolepis), a long-lived flatfish, is complicated by possible ontogenic and sex-specific variation in migration. Archival tags promise the ability to help uncover long-term movement patterns at the individual level, if the tags can be retained and recovered from healthy fish. We examined fifteen individuals (69–90 cm fork length) for long-term physiological response to intracoelomic implantation of three types of archival tags: fully internal, internal with right angle protruding light stalk, and internal with straight protruding light stalk. Tags represented 0.05–0.16% of initial fish weights. Fish were reared at 10.8 ± 1.1°C for 59 weeks post-surgery. One fish died after 39 weeks from thermal stress unrelated to the surgical procedure. Temporal variation in behavior of tagged fish was indistinguishable from that of controls (n = 15 tagged, 5 controls). Treatment and control-group fish grew at similar rates. No tag expulsion or physiological response was evident in the individual that died at 39 weeks, but nine of eleven individuals dissected at the end of 59 weeks had developed internal responses. These responses ranged from deposition of fibrous protein and/or calcitic material on tag surfaces to partial or full tag encapsulation in either the visceral peritoneal layer (fully-internal tags) or the intestinal mesenteries (stalk-bearing tags). The responses were within the range reported for other pleuronectids implanted with tags of similar configuration and may have implications for design and interpretation of long-term tagging studies. Encapsulation may reduce the probability of tag recoveries even in the absence of tag expulsion, especially in species eviscerated at sea.     

Retention of visible implant tags by juvenile brown trout

The retention and readability of visible implant (VI) tags were evaluated in juvenile brown trout. The tags were implanted in the adipose eyelid tissue posterior to the left eye, in a total of 6697 fish in 18 groups. During the first year, tag retention increased with tagging experience, from 58 to 64% in 3–summer–old fish and from 86 to 96% in 4–summer–old fish. The effect of fish size at tagging on tag loss was clear in the 3–summer–old groups in 1991 (ANOVA, P = 0.00001). Tag retention in 3–year–old and 4–summer–old fish in 1992 and 1993 varied from 96 to 99% and the handling of the fish after tagging affected retention significantly ( t –test, P = 0.0002), the average being 98.7% for those transposed by submerging and 96.5% in those transposed by dropping. After inspection the fish were released into a natural environment. On recapture after 6 months or more the red tags (faded almost to white) and yellow tags (originally close to white) were difficult to distinguish. No infection or tissue damage was found after either inspection or stocking.     

Tag retention and survival of juvenile bighead carp implanted with a dummy acoustic tag at three temperatures

Bighead carp Hypophthalmichthys nobilis and silver carp Hypophthalmichthys molitrix (together, the bigheaded carps) are invasive fishes in North America that have resulted in substantial negative effects on native fish communities and aquatic ecosystems. Movement and behavior of adult bigheaded carps has been studied previously using telemetry, while similar studies with juvenile bigheaded carps have yet to be attempted. Recent technological advances in telemetry transmitters has increased the availability of tags sufficiently small enough to implant in juvenile carps. However, the effects of surgical implantation of telemetry tags on juvenile bigheaded carps have not been evaluated. We determined tag retention and survival associated with surgical implantation of acoustic telemetry tags into juvenile bighead carp (range 128–152 mm total length) at three temperatures (13, 18, and 23°C). In addition, we assessed the effect of surgically implanted transmitters on the fitness, defined as changes in weight or critical swimming speed, of carp implanted with transmitters. Survival was high among tagged fish (85%) with 47% of tags retained at the conclusion of the 45‐day study. No substantial decline in fitness of the fish was observed in tagged fish compared to untagged fish.     

Evaluation of external operculum loop tags to individually identify cage-cultured Atlantic halibut Hippoglossus hippoglossus in commercial research trials

The growth, survival and tag retention of double-tagged [external FT4 lock-on (FT4) and internal passive integrated transponder (PIT)-tagged] Atlantic halibut Hippoglossus hippoglossus were compared to internal PIT-tagged controls in a randomized trial. The objective was to assess the suitability of these tags for monitoring the performance of individual fish in longitudinal trials under commercial cage-culture conditions in the lower Bay of Fundy, New Brunswick, Canada. The FT4 tags were chosen due to their similarity to tags used by investigators to track H. hippoglossus in the wild. A subset of the population randomly received an external FT4 tag inserted through the operculum and were monitored over a 1105 day period. The specific growth rate of FT4-tagged fish was significantly reduced in the first sea summer with no significant difference observed for the remainder of the trial. The differential growth in the first sea summer created a relative size advantage, permitting controls to increase in size significantly faster than FT4 fish in all subsequent periods. The FT4 tags did not significantly influence survival under normal commercial cage-culture conditions. Results, however, suggest that the survival of FT4-tagged H. hippoglossus may be compromised during stressful handling events. Tag retention of FT4 tags was acceptable with 76% of tags remaining at the end of the 1105 day trial. FT4 tags proved to be an effective method to identify individual H. hippoglossus, with the caveat that they seriously bias productivity measures in commercial research trials.     

Use of genetic tags to identify captive-bred pallid sturgeon (<Emphasis Type="Italic">Scaphirhynchus albus</Emphasis>) in the wild: improving abundance estimates for an endangered species

The ability to distinguish captive-bred and natural-origin individuals in the wild is critical for evaluating the impact of captive breeding programs on natural populations. Continued persistence of endangered pallid sturgeon (Scaphirhynchus albus) in the Missouri River is largely dependent on captive breeding efforts that spawn natural-origin adults in fish hatcheries and release their progeny into the wild. Prior to release, hatchery-origin individuals are physically marked so they can be distinguished from natural-origin individuals when recaptured. During the years 2004–2006, 24 unmarked juvenile pallid sturgeon tissue samples were collected in the Missouri River downstream of Gavins Point Dam, South Dakota, USA that were presumed natural-origin. However, these individuals were similar in size to hatchery-origin fish released in this area raising concerns that these individuals were actually hatchery-origin fish with lost or malfunctioning tags. We used microsatellite based parentage analysis to determine if the unmarked fish were members of hatchery families that had been released in this area. This retrospective genetic tagging approach revealed that 23 of 24 unmarked fish were indeed hatchery-origin. The origin of the remaining individual remains unknown because genetic samples were not available from all of the families released below the dam and the unassigned fish may have originated from one of these un-sampled families. These results provide important insight into the conservation status of endangered pallid sturgeon as well as provide data important for guiding management decisions. Our results also demonstrate the efficacy of using genetic tags as an alternative or complimentary approach to physically marking individuals.     

The Effect of Carlin Tags on Survival and Growth of Anadromous Arctic Charr, Salvelinus Alpinus

Fish tagging methods are important tools in the research and management of salmonids; the Carlin tag is widely used, especially in anadromous salmonids. However, this tagging method may interfere with fish behaviour and increase post-smolt mortality. To estimate Carlin-tag-inflicted mortality in Arctic charr, we used jet injection of alcian blue (colour tags) as a control. Recapture rates were higher for the colour-tagged fish than for the Carlin-tagged fish for both one- and two-year-old smolts. For one-year-old smolts in 1992, the recapture rate was 18.9% for colour-tagged fish and 10.0% for Carlin-tagged ones. For two-year-old smolts in the same year, 34.0% of colour- and 28.6% of Carlin-tagged fish were recaptured; in 1993, recapture rates were 17.2% and 6.3% for colour- and Carlin-tagged fish, respectively. Colour-tagged one-year-old Arctic charr also grew faster than their Carlin-tagged counterparts. No differences in growth rates were found between tagging methods in two-year-olds. These results imply that for hatchery-reared Arctic charr, survival rates using Carlin tagging may be half to one third that of colour tagging. Growth was also higher among colour-tagged fish, indicating that Carlin tags alter the behaviour of fish in the sea.     

Long‐term effects of passive integrated transponder tagging (PIT tags) on the growth of the yellow European eel (Anguilla anguilla (Linnaeus, 1758))

Passive Integrated Transponder tags (PIT tags) are recommended as the most suitable method for tagging fish on the basis of their high retention and fish survival rates. The objective of this study was to determine the long‐term effects (between 1 and 11 years) of the PIT tag on the growth of the yellow European eel (Anguilla anguilla). A difference of more than 50% was observed in the growth of marked and unmarked yellow eels. If this is a general long‐term effect in all eels, it would seriously restrict the use of PIT tags for studying the dynamics of European eel populations, and so for their management.     

The fate of dead fish tagged with biotelemetry transmitters in an urban stream

Mortality is a key factor in understanding the population dynamics of fish. For studies using biotelemetry, missing individuals pose a challenge since the ultimate fate of both the animal and the tag are unknown. In this study, we document three releases of carcasses in a simulated small-scale summer fish kill in a small urban stream using juvenile white sucker (Catostomus commersonii). Passive integrated transponder (PIT) and radio tags were affixed to carcasses that were tracked to determine the fate of both the dead fish and the tags. Mean daily dispersal distances ranged from 0.0 to 7.6 m day^?1 and included downstream and lateral dispersal. Of the 44 radio-tagged carcasses, 26 tags (and presumably carcasses) were consumed by scavengers; the majority were consumed by snapping turtles (Chelydra serpentina) with fewer carcasses scavenged by great blue heron (Ardea herodias), raccoon (Procyon lotor) and muskrat (Ondatra zibethicus). We also contrasted the decomposition rates of in-stream carcasses with those experimentally placed on the riverbank and found that while there was no significant difference in the time to carcass evisceration, the rate of decomposition was more rapid in-stream compared to on-shore. Radio tag loss during the decomposition study was moderate (one of three lost); PIT tag loss occurred when carcasses became eviscerated, typically by invertebrates. By examining the role of scavengers, dispersal and decomposition, it is possible to understand the fate of dead fish, the fate of tags and role of mortality in tagging experiments and the connections between stream and riparian habitats and organisms. This information will help inform the interpretation of potential mortalities in fish tracking studies and improve fish kill investigations.     

Training considerations for the intracoelomic implantation of electronic tags in fish with a summary of common surgical errors

Training is a fundamental part of all scientific and technical disciplines. This is particularly true for all types of surgeons. For surgical procedures, a number of skills are necessary to reduce mistakes. Trainees must learn an extensive yet standardized set of problem-solving and technical skills to handle challenges as they arise. There are currently no guidelines or consistent training methods for those intending to implant electronic tags in fish; this is surprising, considering documented cases of negative consequences of fish surgeries and information from studies having empirically tested fish surgical techniques. Learning how to do fish surgery once is insufficient for ensuring the maintenance or improvement of surgical skill. Assessment of surgical skills is rarely incorporated into training, and is needed. Evaluation provides useful feedback that guides future learning, fosters habits of self-reflection and self-remediation, and promotes access to advanced training. Veterinary professionals should be involved in aspects of training to monitor basic surgical principles. We identified attributes related to knowledge, understanding, and skill that surgeons must demonstrate prior to performing fish surgery including a “hands-on” assessment using live fish. Included is a summary of common problems encountered by fish surgeons. We conclude by presenting core competencies that should be required as well as outlining a 3-day curriculum for training surgeons to conduct intracoelomic implantation of electronic tags. This curriculum could be offered through professional fisheries societies as professional development courses.     

Retention of loop,monel, and passive integrated transponder tags by wild,free‐ranging Lake Sturgeon (Acipenser fulvescens Rafinesque, 1817)

Tagging or marking of fish is instrumental to fisheries biologists and managers seeking to distinguish groups of fish, track movement or migration patterns, and monitor population characteristics. However, tag loss can inhibit the ability of biologists and managers to reach these objectives. The ability of Lake Sturgeon to live for long periods of time and reach large sizes, in combination with their dynamic spawning activity, requires tags to be retained under a variety of environmental and physically demanding conditions. This study evaluated tag retention of loop, monel, and passive integrated transponder (PIT) tags on wild, free‐ranging Lake Sturgeon in Lake Huron and the St. Clair – Detroit River System. Lake Sturgeon in this study were double‐tagged with both a PIT tag under one of the three anterior‐most dorsal scutes and an external tag (loop or monel) at the base of the dorsal fin. Fish were at large for up to 16 years. Overall, tag loss for PIT tags was 1% followed by monel tags at 12% and loop tags at 36%. Tag loss for loop tags was higher when the initial length of Lake Sturgeon tagged was smaller. Tag loss for monel tags increased with time at large but was not related to length at initial tagging. Monel tags left behind abrasion marks when attached to smaller Lake Sturgeon. PIT tag retention was higher than reported in previous studies that tagged other sturgeon species in different body locations. Monel tag retention was higher than other external tag types evaluated in previous studies while loop tags had similar retention rates to external tag types. Most previous studies on tag retention of sturgeon species were of shorter duration and conducted in laboratory settings, therefore loop tags may have performed more favorably during studies under short term laboratory settings. Results of this study suggest that PIT tags inserted below dorsal scutes represent a viable option for long‐term tracking of Lake Sturgeon. Monel tags attached at the base of the dorsal fin also seem to be a viable option relative to other external tag types, but should be limited to larger sturgeon as they can leave behind abrasion marks.     

A stomach sampler for use on live fish

A stomach sampler for live fish is described and its construction outlined; 50 adult perch were sampled, subsequently killed and dissected to assess the efficiency of the device. Survival of previously sampled fish was followed using individually recognisable dorsal fin tags.     

Migratory patterns of anadromous white-spotted charr Salvelinus leucomaenis in Eastern Hokkaido, Japan: The solution to a mystery?

We evaluated the migratory patterns of white-spotted charr in eastern Hokkaido, Japan using: (1) field observation of fish, (2) salinity-recording archival tags, and (3) analysis of otolith Sr and Ca concentrations. Field observations suggest that the majority of anadromous white-spotted charr outmigrate to the sea in spring (April to June) and ascend the river between late summer and autumn (August to November). Salinity records from archival tags revealed a fluctuating pattern consisting of both low and high values within a month, indicating frequent short-term movements between freshwater (including non-natal rivers) and brackish/salt water habitats. Otolith Sr:Ca ratios exhibited a sharp rise at about 40–50% of the otolith radius, which was followed by several spikes consisting of both low and high values, indicating that fish migrated between freshwater and marine environments multiple times during their life history. However, the peaks in Sr:Ca ratios were generally associated with annulus zones on the otolith, indicating that the anadromous migration was generally an annual event.     

An investigation of the advantages of autumn and spring stocking with brown trout Salmo trutta L. in a Yorkshire reservoir

Batches of trout have been introduced into Chelker Reservoir in Yorkshire in the autumn and spring since the 1870's for angling purposes. Six batches of tagged, hatchery-reared brown trout Salmo trutta L. were introduced from autumn 1966 to spring 1969. During the angling season fish introduced in the spring give better catches than those stocked in the autumn. At the beginning of the season the larger fish in the spring batch are caught more often than the smaller fish from the same batch. The larger fish in the autumn batch are caught more often than the smaller fish from that batch throughout the season. The population, available to the angler from the shore was estimated to be 1491 in 1968, with 722 fish/km of shoreline. More fish survive to a second year in the reservoir than is apparent from the number of tags returned. Fish introduced in the spring usually begin growing before those introduced in the autumn, thereafter growth rates varied. The growth rate was independent of the number offish stocked up to the numbers put in.
Batches of tagged trout were retained at the hatchery up to nine months to gain relevant experience of post-tagging mortalities, tag loss rate and effect of tags on growth.     

A Field Evaluation of an External and Neutrally Buoyant Acoustic Transmitter for Juvenile Salmon: Implications for Estimating Hydroturbine Passage Survival

Turbine-passed fish are exposed to rapid decreases in pressure which can cause barotrauma. The presence of an implanted telemetry tag increases the likelihood of injury or death from exposure to pressure changes, thus potentially biasing studies evaluating survival of turbine-passed fish. Therefore, a neutrally buoyant externally attached tag was developed to eliminate this bias in turbine passage studies. This new tag was designed not to add excess mass in water or take up space in the coelom, having an effective tag burden of zero with the goal of reducing pressure related biases to turbine survival studies. To determine if this new tag affects fish performance or susceptibility to predation, it was evaluated in the field relative to internally implanted acoustic transmitters (JSATS; Juvenile Salmon Acoustic Telemetry System) used widely for survival studies of juvenile salmonids. Survival and travel time through the study reach was compared between fish with either tag type in an area of high predation in the Snake and Columbia rivers, Washington. An additional group of fish affixed with neutrally-buoyant dummy external tags were implanted with passive integrated transponder (PIT) tags and recovered further downstream to assess external tag retention and injury. There were no significant differences in survival to the first detection site, 12 river kilometers (rkm) downstream of release. Travel times were also similar between groups. Conversely, externally-tagged fish had reduced survival (or elevated tag loss) to the second detection site, 65 rkm downstream. In addition, the retention study revealed that tag loss was first observed in fish recaptured approximately 9 days after release. Results suggest that this new tag may be viable for short term (<8 days) single-dam turbine-passage studies and under these situations, may alleviate the turbine passage-related bias encountered when using internal tags, however further research is needed to confirm this.     

Multiple CC chemokines in channel catfish and blue catfish as revealed by analysis of expressed sequence tags

Chemokines represent a superfamily of chemotactic cytokines involved in recruitment, activation and adhesion of a variety of leukocyte types to inflammatory foci, as well as in the organization and maintenance of lymphoid organ architecture and in normal developmental processes. Nearly all chemokines have been identified in human and mouse, but only a handful of fish chemokines have been identified. Here we describe 14 distinct chemokines from channel catfish and blue catfish identified by analysis of 30,000 expressed sequence tags. Based on sequence analysis, sequence similarity, and the arrangement of the conserved cysteine residues, all 14 chemokines were identified as members of the CC subfamily. Phylogenetic analysis did not reveal clear evidence of orthology of the catfish and human or mouse chemokines. Similarity analysis indicated that nine of the 14 CC chemokines were identified for the first time in fish. The availability of this pool of catfish CC chemokines should facilitate rapid identification and phylogenetic analysis of CC chemokines from other fish and related species.