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PIT Tags (pit + tag)
Selected AbstractsDetection efficiency of multiplexed Passive Integrated Transponder antennas is influenced by environmental conditions and fish swimming behaviourECOLOGY OF FRESHWATER FISH, Issue 4 2009J. C. Aymes Abstract,,, The efficiency of a Passive Integrated Transponder (PIT)-tag detection system was tested during a 23-day experiment using a permanent digital video to record the passage of fish through multiplexed antennas. Coupling video to the PIT system allowed the detection of error sources and the correction of erroneous data. The efficiency of the detection system and its variation were investigated according to fish swimming speed, direction of movement and individual fish behaviour. Influence of time and environmental conditions on detection results were also checked. The PIT tag system was 96.7% efficient in detecting fish. Upstream movements were better detected (99.8%) than downstream movements (93.7%). Moreover, results showed that efficiency rate was not stable over the experiment; it was reduced on stormy days. Several sources of errors were identified such as sub-optimal orientation of the PIT tag relative to the antenna plane, the influence of fish swimming speed, individual fish behaviour and influence of environmental conditions. [source] Evaluation of passive integrated transponder tags for marking the bullhead (Cottus gobio), a small benthic freshwater fish: effects on survival, growth and swimming capacityECOLOGY OF FRESHWATER FISH, Issue 3 2007G. Knaepkens Abstract,,, This study examined potential adverse effects of surgically implanted passive integrated transponder (PIT) tags (12 × 2.1 mm) on bullhead (Cottus gobio L.) of three different length-classes (I: 50,64 mm, II: 65,79 mm, III: 80,94 mm). During a 7-week laboratory experiment, the rate of PIT tag loss, incision closure time, survival, growth and swimming capacity were tested. The PIT tag weight to fish body weight ratio varied between 1.04% and 4.85%. The mean incision closure time differed significantly among length-classes and varied between 2.8 (I) and 4.3 (III) weeks. Nevertheless, PIT tag retention did not differ among length-classes and was ,90%. The survival of untagged, sham-tagged and PIT-tagged bullheads was ,90% and did not differ within or among length-classes. Finally, within each length-class, there was no difference in growth and swimming capacity among treatments. Hence, these results suggest the applicability of PIT tags for individually tagging bullheads ,50 mm. [source] Evaluation of VIE and PIT tagging methods for juvenile cyprinid fishesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2009J. D. Bolland Summary Retention and mortality associated with visible implant elastomer (VIE) and passive integrated transponder (PIT) tagged juvenile chub [Leuciscus cephalus (L.)], dace [Leuciscus leuciscus (L.)] and roach [Rutilus rutilus (L.)] were evaluated. PIT tag retention (96.6,100%) was higher than VIE over the 6-month duration of the experiment. VIE retention was significantly better in the head (96.3,98.8%) than in the fins (78.8,90.9%) the first month after tagging, but the opposite was found after 6 months (head = 21.5,57.5%; fins = 77.2,88.8%). Survival was not significantly different from controls for any treatment, except dace tagged with 23-mm PIT (significantly influenced by mass of fish at tagging) and sham PIT tagged dace, because of initial losses. PIT tags are recommended as the most suitable method for tagging individual juvenile chub, dace and roach based on high retention and survival. VIE implantation in the head (studies < 30 days) and fins (studies > 30 days) could provide a cheap, batch-marking alternative, provided retention rates are monitored. [source] Testing assumptions of mark,recapture theory in the coral reef fish Lutjanus apodusJOURNAL OF FISH BIOLOGY, Issue 3 2008C. L. Wormald This study tested assumptions of the Cormack,Jolly,Seber capture,mark,recapture (CMR) model in a population of the tropical snapper Lutjanus apodus in the central Bahamas using a combination of laboratory and field studies. The suitability of three different tag types [passive integrated transponder (PIT) tag, T-anchor tag and fluorescent dye jet-injected into the fins] was assessed. PIT tags were retained well, whereas T-anchor tags and jet-injected dye were not. PIT tags had no detectable effect on the rates of growth or survival of individuals. The capture method (fish trapping) was found to provide a representative sample of the population; however, a positive trap response was identified and therefore the assumption of equal capture probability was violated. This study illustrates an approach that can be used to test some of the critical assumptions of the CMR theory and it demonstrates that CMR methods can provide unbiased estimates of growth and mortality of L. apodus provided that trap response is explicitly modelled when estimating survival probability. [source] Reduced sexual maturation in male post-smolt 1+ Atlantic salmon (Salmo salar L.) by dietary tetradecylthioacetic acidAQUACULTURE RESEARCH, Issue 5 2009Henriette Alne Abstract In the present study, the possible effect of dietary treatment on early sexual maturation in post-smolt Atlantic salmon, without any negative effect regarding growth, was investigated. The experiment was performed using 4400 individually marked (Pit tag) 1+ salmon, fed either a control diet or a diet supplemented with 0.5% tetradecylthioacetic acid (TTA) in duplicates for 3, 6 or 12 weeks after sea transfer. Compared with the control, dietary supplementation of TTA resulted in a threefold reduction in incidence of sexual mature males (0.6% vs. 1.8%). A curve-linear relationship between relative reduction in maturation and weeks of feeding TTA was found, indicating that the effect is most marked as a result of the first weeks of feeding and then levelling off. No negative dietary impact on growth was observed. As the level of fat in the muscle was reduced by dietary TTA, it seems that post-smolt supplemented dietary TTA do not accumulate high enough energy stores to start the maturation process, whereas the energy-enhancing effect of TTA due to increased fatty acid oxidation capacity may maintain the growth potential. Compared with immature salmon, sexually maturing fish revealed increased spring growth before the onset of maturation. [source] | ||||||||||