Untagged Controls Research Articles

Retention of passive integrated transponder tags in hatchery brook trout: Effect of tag size, implantation site, and double tagging

AbstractA fundamental assumption of mark‐recapture studies is that individuals do not lose their marks or tags, because tag loss can lead to biased parameter estimates. Retention of 8‐mm full‐duplex and 12‐mm half‐duplex passive integrated transponder (PIT) tags implanted in the abdomen, opercular musculature, and dorsal sinus of age‐0+ hatchery male brook trout (Salvelinus fontinalis) was evaluated in the laboratory. Treatments included single‐ and double‐tagged fish. Survival, growth, and tag retention were monitored for 181–187 days for 640 tagged fish and 80 untagged controls. Survival to 180 days ranged 95%–100% and was not affected by tagging. PIT‐tagging caused a short‐term reduction in growth rates. Tag retention to 180 days was 100% for dorsal implantation, 83.0% with 8‐mm tags in the operculum, 97.5% with 8‐mm tags in the abdomen, and 99.6% with 12‐mm tags in the abdomen. Retention of opercular tags was positively related to size at tagging. Tag loss was independent of whether fish were single‐ or double‐tagged. Double tagging with one full‐ and one half‐duplex PIT tag in different body locations would hedge against data loss relative to single tagging, especially for longer‐lived and iteroparous species where tag loss through time is more likely.

Detection of Mu‐Opioid Receptors in SH‐SY5Y Human Neuroblastoma Cells by Flow Cytometry

PurposePharmacological actions of morphine are mediated through G‐protein‐coupled receptors (GPCRs), specifically mu‐opioid receptors (MORs). Morphine‐induced activation of GPCRs inhibits adenylyl cyclase and decreases 3’,5’‐cyclic adenosine monophosphate (cAMP). Neuroblastoma SH‐SY5Y cell lines endogenously express MORs. Our aim was to develop a flow cytometry (FC) assay for MORs on the surface of SH‐SY5Y cells. This assay will provide in‐depth understanding of opioid‐induced downstream cAMP signaling.MethodsSH‐SY5Y human neuroblastoma cells (ATCC® CRL2266™) were grown in DMEM/10% FBS and maintained in a humidified incubator at 37ºC/5%CO2. Cells were seeded in 96‐well white, opaque‐bottom plates (5×104cells/well). Transfection conditions were optimized using ViaFect™ (Promega™) and a stably transfected SH‐SY5Y cell line was established using GloSensor™ ‐23F cAMP plasmid (Promega™) containing hygromycin‐resistance gene. Cells were washed in FACS buffer (PBS + 2% FBS) and incubated for 1h at room temperature with monoclonal rabbit anti‐MOR antibody (Ab) (Novus Biologicals). Following the wash, cells were incubated with donkey anti‐rabbit secondary Ab (Abcam). We used monoclonal mouse anti‐muscarinic Ab (Novus Biologicals) and donkey anti‐mouse secondary Ab (Jackson Labs). Both secondary Abs are bound to a fluorophore (Alexa Fluor® 488) which emits light when excited by FITC channel frequency (excitation/emission: 495nm/519nm). A Cytoflex flow cytometer (Beckman Coulter) analyzes cells for FITC fluorescence emission. Multiple primary and secondary concentrations were tested; Human TruStain Fc blocker (BioLegend) was used to prevent nonspecific tagging.ResultsRelative fluorescence emission was measured as percent shift increase from the untagged control group. Because MOR Abs have been tested in a limited capacity, we tested for presence of muscarinic receptors (another endogenously expressed GPCR in these cells) to establish the FC assay. Initial trials with low primary and secondary MOR Ab concentrations showed limited shifts (~1‐2%), however, muscarinic receptor Abs bound to their receptors at lower concentrations compared to MOR Abs. Testing muscarinic receptors showed secondary Ab concentration‐dependent fluorescence shifts indicating that the technique was viable. Studies with increased concentration ratios of primary and secondary MOR Abs showed secondary Ab concentration‐dependent response with maximum % shifts reaching up to 16%. Use of Fc blocker eliminated nonspecific binding, increasing the percent shift.ConclusionCompared to untagged controls, antibody‐tagging on SH‐SY5Y cell surface produced greater immunofluorescence indicating presence of MORs in both non‐transfected and 23F cAMP plasmid transfected cells. Direct binding of receptor modulators leads to altered downstream cAMP signaling as shown in previous in vitro signaling studies and behavioral mouse models. Detection of the MOR is essential to ensure that cAMP signaling is regulated by MOR agonists. In future studies, we plan to investigate the expression of endothelin‐A receptor (ETAR) and explore potential interactions between MOR and ETAR in SH‐SY5Y cells.

From 95 to 59 millimetres: a new active acoustic tag size guideline for salmon

Two laboratory studies evaluated small Chinook salmon (Oncorhynchus tshawytscha) (36–99 mm fork length (FL), 0.7%–26.7% tag burden) survival, tag retention, and growth (n = 539) and critical swimming speed (Ucrit; n = 241). Fish were implanted with a new active acoustic tag and compared with untagged controls at 12 and 17 °C. Across studies, no temperature differences were detected. All control fish survived. All tagged fish ≥58 mm FL survived and retained their tags. Regression models predicted ≥98.6% survival and retention for tagged fish ≥58.6 mm FL or ≥1.9 g (4.2% tag burden). No growth differences among treatments were identified. Spline regression analysis indicated Ucrit was similar for control and tagged fish that measured ≥57.3 mm FL. We recommend tagging salmon ≥59 mm FL or ≥1.9 g (≤4.2% tag burden), although the guideline should be confirmed in a field setting. Study results represent an important step towards using the new active tag in acoustic telemetry field studies that estimate short-term (30-day) survival of small salmonids.

Evaluation of a European sea bass (Dicentrarchus labrax L.) post-larval tagging method with ultra-small RFID tags

Individual tagging is key to a better understanding of early life stages in fish. Very small RFID transponder microchips (500 × 500 × 100 μm, 82 μg) are now available. The aim of this study was to develop a protocol to tag European sea bass (Dicentrarchus labrax L.) larvae from 61 days post-hatching (dph; standard length ~10 mm) to 96 dph (standard length ~28 mm) through intra-coelomic implantation of microchips. The suitability of such a tagging procedure was evaluated, with the purpose of determining the minimal fish age and body size for microchip tagging without adverse effects on survival and growth performance.We produced an experimental population composed by 50:50 normally pigmented larvae and albino larvae through artificial fertilization. Five tagging trials were performed over 35 days, in fish aged 61, 75, 83, 89 and 96 dph. Each time, 50 normally pigmented fish were tagged, while 50 albino fish were used as controls. Mortality was recorded daily, while biometric measurements were performed at 75, 83, 89, 96, 103 and 110 dph via image analysis.Microchip tagging was possible in larvae from an age of 75 dph (standard length ~20 mm), with satisfactory performance in terms of survival rate (between 84 and 98% 24 h after tagging) and growth rate, and without significant differences in comparison with the untagged controls. In contrast, tagging before 75 dph is not to be recommended, as the age group 61 dph was the most affected in terms of survival (only 62% of fish survived 24 h after tagging) and growth rate, showing significant differences compared to the untagged controls. The overall microchip reading success rate for the age groups throughout the experiment was 51.4%, the overall reading success rate at each biometric measurement was 48.2%, probably due to the change in orientation of the microchip inside the fish body cavity.The tagging protocol developed was then overall successful, albeit with a moderate reading success. Precocious tagging could allow the collection of new types of data (individual, longitudinal) related to larval development, behavioral studies, physiological and immunological investigations. Future tests could focus on the effects of tagging on baseline locomotion and behavior, as well as the suitability and the efficiency of intramuscular microchip tagging on larger fish.

TAG-RNAi overcomes off-target effects in cancer models.

RNA interference offers therapeutic opportunities for the clinical targeting of otherwise undruggable oncogenes. However RNAi can have off-target effects that considerably increase treatment risks. To manage these side effects and allow an easy subtraction of their activity in healthy tissues, we present here the TAG-RNAi approach where cells that are not designated targets do not have the mRNA tag. Using TAG-RNAi we first established the off-target signatures of three different siRNAs specific to the Cyclin D1 oncogene by RNA-sequencing of cultured cancer cells expressing a FLAG-HA-tagged-Cyclin D1. Then, by symmetrical allografts of tagged-cancer cells and untagged controls on the left and right flanks of model mice, we demonstrate that TAG-RNAi is a reliable approach to study the functional impact of any oncogene without off-target bias. Finally we show, as examples, that mutation-specific TAG-RNAi can be applied to downregulate two oncogenic mutants, KRAS-G12V or BRAF-V600E, while sparing the expression of the wild-type proteins. TAG-RNAi will thus avoid the traditional off-target limitations of RNAi in future experimental approaches.

Evaluation of Tag Retention, Healing, Growth, and Behavior in Age‐0 Muskellunge Following Acoustic Transmitter Implantation

AbstractThe development of small acoustic transmitters has enabled researchers to monitor earlier life stages and smaller fish species than was previously possible. The underlying assumptions of any telemetry study are minimal tag loss and negligible effects on the behavior, survival, and growth of tagged individuals. To that end, tag retention, healing, survival, specific growth rates, and behavior were evaluated for 96 age‐0 MuskellungeEsox masquinongy(TL[mean ± SD] = 205 ± 10 mm) from three treatment groups. Tagged fish were compared to untagged controls and sham fish (fish that had undergone anesthesia and laparotomy but not transmitter implantation). Thirty‐two fish (tagged group) were implanted with one of the smallest commercially available acoustic transmitters (Juvenile Salmon Acoustic Telemetry tag; 12.0 × 5.3 × 3.7 mm, 0.217 g in air, >120‐d tag life) and monitored in a 4‐month, overwinter tank experiment. Tricaine methanesulfonate was used for anesthesia, incisions were closed with a synthetic absorbable monofilament, and all surgeries were conducted by a single trained researcher. All tags were retained throughout the experiment; surgical wounds healed within 30 d, 32% of sutures were retained at 120 d postsurgery, and survival did not differ between treatments. No biologically significant effects of tagging on mean relative growth rates (percent change in weight/d) were observed among the three groups (tagged, untagged, and sham fish) at 4 months postprocessing. The reaction of tagged fish to a moving object within 15 minutes after tagging was slower than the reaction at 7 d postsurgery, reiterating the importance of testing appropriate sedation methods prior to releasing fish in field studies. Results validate the utility of surgical implantation of small acoustic transmitters in juvenile Muskellunge for future studies, although immobilization methods for early life stages require further study.

Implantation of a New Micro Acoustic Tag in Juvenile Pacific Lamprey and American Eel.

Juvenile Pacific Lamprey and American eels were used for laboratory evaluations to determine potential effects from tag implantation. Telemetry technology has been identified as a way to obtain more detailed information on movement and behavior across a broader spatial scale than is possible with other known technology. The purpose of this method is to provide a detailed step by step instruction on tag implantation for both lampreys and eel. For laboratory studies using actively migrating juvenile Pacific Lamprey (120-160 mm), we determined that the presence of the tag did not alter the swimming ability between tagged and untagged Individuals or have any significant tag loss (<3%). Similar results were determined during laboratory testing of Yellow phase American Eels (113-175 mm). No mortality occurred during a 38-day holding period and there was minimal tag loss (3.8%). The presence of the tag did not have any significant effect on the swimming ability or survival of tagged eels compared to untagged controls and there was minimal tag loss.

Evaluation of the Effects of Marking Pacific Lamprey Ammocoetes with Visual Implant Elastomer, Coded Wire Tags, and Passive Integrated Transponders

AbstractPopulations of Pacific Lamprey Entosphenus tridentatus have declined in multiple portions of the Columbia River basin and some Pacific coastal rivers due to a variety of factors. Given the ecological and cultural significance of the species, federal, state, and tribal resource managers have increased conservation efforts, though a lack of basic information about the biology of wild lampreys hinders some of these actions. Multiple tagging technologies have been used to mark migrating metamorphosed juvenile lampreys for research, but these methods have not been experimentally tested for use on the smaller ammocoete stage. Lamprey ammocoetes (total length range = 29–83 mm) were assigned to groups marked with three common tags (visible implant elastomer [VIE], coded wire tags [CWT], and passive integrated transponders [PIT]) or to untagged controls, and mortality and tag retention were monitored. Growth and burrowing ability were also measured to determine the potential for sublethal effects of tagging. At the end of the 137‐d study, no mortality was measured in the VIE group and tag retention was 100%. Fish in the CWT group also exhibited no mortality, though tag retention was 64%. Fish in both of these groups did not exhibit any differences in growth or burrowing performance when compared with controls. The PIT group was the only group to experience mortality at a rate of 62.5%. While the larger fish within the PIT group displayed higher survival, the smallest fish that survived PIT implantation was 70 mm. Tag retention was 89% for surviving lampreys in the PIT group. All three techniques were successfully used to mark small ammocoetes, though researchers should carefully consider the benefits and potential effects on animal behavior when choosing which method to use.Received September 29, 2016; accepted January 31, 2017 Published online May 1, 2017

Preliminary Studies on the Use of Pit Tags to Evaluate Abalone Restocking

ABSTRACT The evaluation of abalone (Haliotis spp.) restocking programs might be improved by the use of microchips attached to seeds [ca. 20–30mmshell length (SL)]. Preliminary studies were conducted to standardize thismethodology and to assess tag retention and the potential impacts of tagging red abalone (Haliotis rufescens) seeds (initial averages: 26 mm SL, 2.5 g total weight) with passive integrated transponder (PIT) tags (9×2mm, Biomark, HPR Plus Reader). Tags were placed in previously made grooves in the shells and glued with a cyanoacrylate adhesive fast cured with sodium bicarbonate. Laboratory trials showed that metabolic rate increased in tagged seeds compared with untagged controls (t = 4.74, P = 0.009) immediately after the tagging procedure, but this effect was not significant after 3 h (t= 1.43, P = 0.23). Food (Macrocystis pyrifera) consumption after 24 h was similar by seeds marked with PIT tags, plastic tags, both tags, and untagged controls (F= 0.12, P = 0.94). Tag retention and survival...

Effect of Harmonic Radar Tagging onLycorma delicatula(Hemiptera: Fulgoridae) Nymphal Mobility and Survivorship

The spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae), has recently emerged as an invasive pest in the United States, threatening the grape and tree fruit industries. The biology of L. delicatula is poorly known. This invasive pest has rapidly spread and established itself in new regions (e.g., South Korea), taking advantage of a wide range of host plants, but virtually no studies of the dispersal capacity and patterns of the species have been published. Harmonic radar tracking provides a new tool to study the dispersal of small animals such as insects in natural field settings. In this study, we discuss procedures that allow secure attachment of harmonic radar tags on the 4th instar nymphs of L. delicatula. The adhesive bond strength between the radar tag and the nymph was sufficiently great for operational use, yielding 431.10 ± 43.37 g forces (mean ± SE). Variations in L. delicatula body size of did not affect the adhesive bond strength. Neither horizontal mobility nor vertical climbing ability of L. delicatula was affected by radar tagging when compared with untagged controls. Also, there was no significant difference in the jumping ability of radar-tagged and untagged insects. Finally, radar tagging did not affect the survivorship of L. delicatula over a 3 d test period. The results of this study indicate that the harmonic radar system can be applied successfully to 4th instars of L. delicatula without changing their mobility and survivorship. This technology facilitates study of the dispersal capacity and behavior of this invasive species under natural field conditions, and this information can serve as a basis for the development of effective monitoring and management strategies.

Effects of a novel acoustic transmitter on swimming performance and predator avoidance of juvenile Chinook Salmon: Determination of a size threshold

The miniaturization of acoustic transmitters enables researchers to tag smaller fish for telemetry studies, thus representing a greater proportion of the population of interest. Fish having a smaller transmitter burden (e.g., the weight of the transmitter relative to the weight of the fish) may also have fewer potential adverse transmitter effects. The development of an injectable acoustic transmitter has led to research that determined the least invasive and quickest method of implantation. Following that research, the objectives of this study were to determine the effects of transmitter implantation on swimming performance and predator avoidance, and to find a minimum size threshold of fish that can be tagged without adversely affecting those responses. To assess critical swimming speed (Ucrit; an index of prolonged swimming performance) and predator avoidance for juvenile Chinook Salmon (Oncorhynchus tshawytscha), fish were split into three treatments: (1) implantation with a dummy injectable acoustic transmitter (IAT treatment), (2) implantation with a dummy injectable acoustic transmitter and passive integrated transponder tag (IAT+PIT treatment), and (3) an untagged control. IAT treatment fish had lower Ucrit values than untagged controls among individuals below 79mm fork length (transmitter burden 3.4–4.0%). Ucrit values for the IAT+PIT treatment were not significantly different from untagged controls and no size threshold was found. There was no significant difference in predator avoidance between fish implanted with the IAT or IAT+PIT compared to untagged controls. These guidelines could provide researchers and managers with a powerful tool to examine behavior and survival of small salmonids.

The suitability of VIE tags to assess stock enhancement success in juvenile European lobsters (Homarus gammarus)

Assessments of stock enhancement programmes for European lobsters (Homarus gammarus) require mark-recapture analysis of stocked individuals. However, established tag technology is deemed unsuitable for extensive use by many current lobster hatcheries, particularly upon the early juvenile stages. We tested the suitability of fluorescent Visible Implant Elastomer (VIE) tags for use in 5-month-old juvenile lobsters. Three treatment groups comprising 348 cultured lobsters in total were used to examine survival, growth and tag retention, and to assess mobility, shelter use and moulting behaviours. Tagging had no significant effect on lobster survival, growth, mobility, shelter use or moult frequency. Survival over 7 weeks was 75% among lobsters tagged with two elastomers, 76% in those with one elastomer and 74% among untagged controls. Mortality during moulting did not increase in tagged (6%) compared to untagged lobsters (9%). We found no evidence that VIE tags cause any negative effects that would be expected to inhibit survival upon wild release, but tag loss had reached 12% in both tagged treatments after 7 weeks and showed no sign of abating. Our study suggests that VIEs effectiveness in discerning cultured lobsters long after wild release may be limited when used in smaller juveniles.

Early individual electronic identification of sea bass using RFID microtags: A first example of early phenotyping of sex-related growth

Although individual electronic tagging using PIT (Passive Integrated Transponder) tags is well established, it is mainly used for fish > 60 mm in length. Since electronic tagging is an ideal identification method, we used RFID (Radio Frequency Identification) microtags (6 mm in length, 1 mm in diameter, 10 mg in mass) to characterize individual fish from the early stages of their development and throughout their lifecycles. We used sea bass, Dicentrarchus labrax (105 day-old fish weighing between 100 and 1100 mg), and studied the effects of intra-coelomic tagging in half the population using different endpoints including survival and tag reading, growth over 6 months and swimming responses. Dead fish were counted daily, biometric data were collected at 21 to 28 days intervals and fish were sexed at the end of the experiment. Behavioral swimming responses following a sudden dark challenge were evaluated after the first three biometric measurements (immediately after tagging, and then 21 and 42 days later). After 6 months, mean survival was 69%, the smallest surviving fish weighed 197 mg at tagging, and success in tag reading was 79% for the size class 300-400 mg after 63 days. No negative effects were observed on growth and most deaths occurred within 15 days after tagging with a first peak after 5 days but that did not particularly affect the smallest individuals. Differences in swimming responses were detected between tagged fish and untagged controls immediately after the surgical procedure with tagged fish swimming more than controls for 45 min. However, after 21 days, the tagged fish swam less than the untagged controls after being placed in the observation tank for 1 h and 45 min. At 42 days post-tagging, no further differences were observed. Overall, results suggested that the tagging method was suitable for fish as small as 400 mg and 36 mm in total length. This type of early tagging method is invaluable for the longitudinal monitoring of individual biological traits (e.g., growth) or for repeated assays with the same individual at distinct time points (e. g., behavior studies). We used it for a first evaluation of early growth differentiation between sexes and demonstrated a 31% mass gain difference in females that was visible as soon as the fish reached 105 days old. This confirms the potential of the method for the selection of early-expressed character traits which could lead to rearing cost savings for the aquaculture research field. (C) 2014 Elsevier B.V. All rights reserved.

Posthandling Survival and PIT Tag Retention by Alewives—A Comparison of Gastric and Surgical Implants

AbstractWe compared survival and tag retention of Alewives Alosa pseudoharengus tagged with PIT tags, using intraperitoneal (IP) surgical implants, gastric implants (GI), and untagged controls held for 38 d. Retention was 100% for IP‐tagged Alewives and 98% for GI‐tagged implants. No significant difference in survival was observed among any of these groups. These results lend support to the use of PIT telemetry for studying fish passage and migration of anadromous herring. Both methods hold promise for improving estimates of freshwater survival of adult anadromous clupeids; further research should make it also possible to refine estimates of adult marine survival.Received February 4, 2013; accepted May 29, 2013

Telemetry tag effects on juvenile lingcod Ophiodon elongatus movement: a laboratory and field study

This study tested the behavioural effects of tagging subyearling and yearling lingcod Ophiodon elongatus with acoustic telemetry tags in laboratory tanks and in the natural environment (Puget Sound, WA). In the laboratory, tagged individuals showed less movement and feeding behaviour soon after tagging than untagged controls. The effect dissipated after c. 1 week, presumably as the tagged O. elongatus recovered from surgery or adjusted to the presence of the tags. This dissipation enabled a field study that compared early-tagged individuals with a long recovery period after tagging to recently-tagged individuals with a short recovery period after tagging. Consistent with findings from the laboratory experiment, recently tagged individuals showed less movement away from three release sites in Puget Sound than early-tagged individuals. Together, the laboratory and field results provide evidence of temporary tag effects on actual movement in the natural environment and provide a method for testing tag effects in the field. This study suggests that subyearling and yearling O. elongatus should be held for a recovery period before release. If holding after tagging is not an option, then movement data collected during the first week should be interpreted cautiously.

Electronic individual identification of zebrafish using radio frequency identification (RFID) microtags

Although individual electronic tagging using passive integrated acoustic (PIT) tags is established, it is mainly for fish >60 mm in length and is unsuitable for fish of <30 mm, like zebrafish. We used radio frequency identification (RFID) microtags (1 mm in diameter and 6 mm in length, with a mass of ~10 mg) to individually identify juvenile zebrafish (length 16-42 mm, mass 138-776 mg) for the first time, and studied the effects of intracoelomic implantation on fish survival and microtag loss, growth, spawning and exploratory behaviour. After 5.5 months, both high survival (82%) and low microtag loss (11%) were achieved. The smallest surviving fish weighed 178 mg, and success in microtag reading was 73% for the size class 350-450 mg (26 mm). Greater success was achieved when fish were larger at the time of tagging but no negative effects on growth were observed for any size class and some tagged fish spawned. No significant differences in behavioural responses could be detected between tagged fish and untagged controls after 2 months. Overall, the results suggest that the tagging method is highly suitable for fish as small as zebrafish juveniles. We think this method will provide significant advances for researchers of the ever-growing fish model community and more generally for all small-fish users. Tagging is essential when one needs to identify fish (e.g. particular genotypes with no external cue), to run longitudinal monitoring of individual biological traits (e.g. growth) or to repeat assays with the same individual at discrete points in time (e.g. behaviour studies). Such a method will find applications in physiology, genetics, behaviour and (eco)toxicology fields.

Suitability of a subcuticular permanent marking technique for scorpions

The primary impediment of long term, high-resolution, ecological studies of scorpions is the difficulty of marking individuals for monitoring and recapture. I tested the use of Visible Implant Elastomer (VIE) as a permanent subcuticular tagging technique in the striped bark scorpion Centruroides vittatus (Say 1821). Mortality and prey capture rates of tagged scorpions did not significantly differ from untagged controls. Tag readability was high and comparable to published studies on other arthropod groups. Animals molted (3 treated, 7 control) and gave birth (1 treated, 2 control) successfully. I recommend VIE tagging as a viable solution to what was a major impediment to the proliferation of fine-scale ecological and population-level field research in C. vittatus and similar arthropods.

Evaluation of passive integrated transponder (PIT) tags in studies of sea urchins: caution advised

We evaluated the effect of passive integrated transponder (PIT) tags on feeding, growth, movement and survival of the sea urchin Strongylocentrotus droebachiensis in field and laboratory experiments. In cages supplied with kelp, 80% of urchins (n = 74) retained their tag during an 80 d field experiment. At the end of the experiment, tagged individuals had a lower growth rate (by 42%), lower gonad index (by 23%), lower survival rate (by 30%), and took longer to right themselves (by 30%) than untagged control urchins. In a 24 h feeding experiment in the field, the consumption rate of kelp was lower for tagged urchins (by 67%) than for untagged controls. In release and recapture experiments in the field, tagged urchins moved shorter distances over 2.5 h (by 30%) than controls. Although PIT tagging had a detrimental effect on all measures of sea urchin performance, activity and survival in the field, there was no detectable effect of PIT tagging on urchin feeding rate or survival in a 10 wk laboratory experiment. Our results suggest that natural stressors, such as wave action, may limit the utility of PIT tags in field studies of urchins.

A field and experimental evaluation of the effect of data storage tags on the growth of cod

The effect of electronic data storage tags (DSTs) on the growth of cod Gadus morhua was evaluated in laboratory and field experiments. In the first laboratory experiment, large DSTs (60 × 18 mm, 3 g in water ) attached externally for 3 months did not have any effect (anova, P &gt; 0·05) on the growth of adult cod (mean ± s.d. 65 ± 4·5 cm total length) relative to untagged adult cod. In a second experiment, small DSTs (34 × 11 mm, 1·5 g in water) implanted into young cod (48·1 ± 4·4 cm) for an 8 month period did not have any effect upon the growth relative to untagged controls (anova, P &gt; 0·05). Length data returned from tagging experiments conducted on adult cod (57·3 ± 7·5 cm) in the North Sea showed that the growth of fish tagged either externally or internally with large DSTs was not different (t‐test, P &gt; 0·05). Attachment wounds, however, provided evidence that external attachment of DSTs should be avoided unless sensor configuration requires access to the external environment, and that internal implantation should be preferred whenever possible.

The Effects of Adipose Fin Clipping and Coded Wire Tagging on the Survival and Growth of Spring Chinook Salmon

AbstractEach year, millions of Pacific salmon are identified by the insertion of a coded wire tag and removal of the adipose fin. To evaluate the effects of adipose fin clipping and coded wire tagging on the survival, growth, and straying of spring Chinook salmon Oncorhynchus tshawytscha, we coded‐wire‐tagged juveniles over a 3‐year period and excised their adipose fins at three hatcheries on the Columbia River. In addition, the study fish and control fish were marked with otolith marks so that returning adults without tags and the untagged controls could be distinguished from untagged strays. We collected otoliths, tags, and length data from adults returning to the three hatcheries. Because the proportions of fish with coded wire tags returning to the hatchery were similar to those released and there was no discernable pattern of increase or decrease, we concluded that coded wire tags and adipose fin marks did not affect juvenile‐to‐adult survival. Although there was an indication that coded‐wire‐tagged fish were more likely to to be smaller when they returned than fish without coded wire tags, the size discrepancy was less than one standard deviation of the natural biological variation in size. Tagged juveniles released at the rearing site did not tend to stray when they returned as adults. Based on these results, we concluded that coded wire tagging is a useful method for gathering information with minimal bias on the fates of groups of fish.