Tagging: on the use of passive integrated transponder (PIT) tags for the identification of fish

To determine the efficacy of passive integrated transponder (PIT) tags for marking rohu Labeo rohita (Ham.) in the selective breeding programme, a series of experiments has been carried out at the Central Institute of Freshwater Aquaculture (CIFA) under the Indo–Norwegian project of ‘Selective breeding of rohu’. Six groups of rohu fingerlings with weight ranging from 2 g to 20 g were tagged with PIT tags to determine a suitable size range for tagging. Fingerlings weighing 8–15 g were found to be quite suitable for tagging with a PIT tag. Recovery of the PIT tag depends upon the survival of tagged fish under field conditions. Rejection of the PIT tag by rohu was observed to be only 0.05%. Through effective management practice, the survival of tagged fish increased up to 95%, and thus tag loss was minimized.     

Tagging juvenile European whitefish (Coregonus lavaretus (L.)) with passive integrated transponders—Impact of fish size on growth performance and tag retention

The study examined the effect of PIT tagging and size on the growth, survival, food conversion, tag retention and wound healing in juvenile European whitefish. Three size classes of juvenile whitefish (class S—body weight (b.w.) approx. 4.0 g; class M—b.w. approx. 8.0 g; class L—b.w. approx. 13.6 g) were tagged with PIT implanted intraperitoneally (TROVAN^®, United Kingdom). These groups formed S‐P, M‐P and L‐P respectively. Fish from the control groups (groups S‐C, M‐C and L‐C) were not tagged. Whitefish from the tagged and control groups were reared for 28 days in recirculating aquaculture systems. Only in the fish from the smallest group (group S‐P) was tagging confirmed to have a negative impact on growth rate and survival, which, after 28 days, was 70% in comparison with 94.4% in group S‐C. The rate of wound healing in all whitefish groups was similar. After 28 days following PIT implantation, all wounds were healed. Short‐term PIT retention (28 days) for all the groups was > 90%, and no differences were noted among groups. In summary, it is recommended that whitefish be PIT‐tagged using the intraperitoneal method after they have attained a body weight > 8 g. Tagging smaller specimens of this species leads to higher mortality.     

Laboratory experiment on survival,growth and tag retention following PIT injection into the body cavity of juvenile brown trout (Salmo trutta)

A laboratory study was conducted to assess the effect of PIT tagging on survival and growth of young-of-the-year brown trout (Salmo trutta) and evaluate PIT tag loss as a function of body size at tagging. Transponders (11.5 mm long and 2.1 mm in diameter) were injected into the peritoneal cavity of fish ranging from 41 to 70 mm fork length (FL) using hypodermic needles. A total of 145 tagged fish and 136 control fish of similar size were reared over 4 weeks. Logistic regressions show that survival rate reached 95% for fish ≥52 mm FL at tagging (with a tag retention rate >70%), and 99% for fish ≥57 mm FL (tag retention rate >80%). No significant effect of tagging on growth (fork length and weight) was detected at the end of the experiment. The specific growth rate varied markedly among PIT-tagged fish regardless of fork length, weight or tag-to-body-weight ratio at tagging. Results suggest that juvenile brown trout larger than 57 mm FL (tag-to-body weight ratio in water <3.4%) can be marked by injection of 11.5 mm PIT into the peritoneal cavity with negligible effects on survival and growth, but this leads to a relatively high tag rejection rate (up to 20%).     

Evaluation of VIE (Visible Implant Elastomer) and PIT (Passive Integrated Transponder) physical tagging systems for the identification of red porgy fingerlings (Pagrus pagrus)

The effect of two physical tagging systems, Visible Implant Elastomer (VIE) and Passive Integrated Transponder (PIT), was evaluated in red porgy (Pagrus pagrus) fingerlings, at different sizes. For VIE tagging, the weight classes were <1 and 1?C5?g and no tag effect was detected on fish growth. There was a significant difference in mortality between tagged and untagged <1?g fish, but not for the 1?C5?g fish. The tag loss rate was null for all sizes, however, tags showed fragmentation. This partial tag loss was evaluated and quantified. Seven VIE colours were compared and arranged from best to worst visibility: green, red, pink, orange, yellow, white and blue. For PIT tagging, 2?C6?g, 5?C10?g and 10?C20?g weight classes were analysed. There was no significant tag effect on fish growth, for any size, nor on mortality from 10?g. Tag loss rate ranged from 2.9 to 5.9%. These results demonstrate that, in red porgy, VIE is a successful tagging system from 2?g onwards whereas PIT system is successful from 10?g onwards. The combination of both systems allows traceability of fish from a very small size on, which is necessary for the implementation of genetic breeding programmes.     

Development and testing of a pedigree‐marking system using visible implant elastomer tags for selective improvement in Morone breeding programmes

The development and testing of a visible implant elastomer pedigree‐marking system was evaluated in sunshine bass, Morone chrysops×Morone saxatilis, and white bass, M. chrysops (Rafinesque). These tags were tested in sunshine bass fingerlings at one of four subdermal body locations (posterior to the eye, dorsal fin musculature, caudal fin musculature or anal fin musculature). Tag visibility decreased with increased sunshine bass growth (63% after 56 days). Visibility differed among body locations, with the caudal and anal tagging locations having lower visibility. White bass fingerlings representing eight genetic groups were then tagged at one of two body locations (left or right subdermal along the dorsal musculature) using one of four fluorescent colours and reared for 42 days in a common garden growth trial. Tag visibility in white bass was 99.5% at 14 days, 98.2% at 28 days and 94.9% at 42 days after tagging. There was a significant change in weight among the eight genetic groups of white bass fingerlings after 42 days (P=0.03). Testing of this pedigree tagging system successfully identified phenotypically different groups of white bass fingerlings.     

Long‐term Effects of Passive Integrated Transponder Tagging on the Growth of Olive Flounder,Paralichthys olivaceus

The effects of passive integrated transponder (PIT) tagging on the growth and survival of olive flounder, Paralichthys olivaceus (initial average mass ± SD: 502 g ± 14.3), were examined for 8 mo. Tag readability in relation to implant position (eyed‐side muscle, blind‐side muscle, and peritoneal cavity) was also documented. The overall weight gain of fish tagged in the eyed‐side muscle (444 g) was significantly less than control and tagged fish in the blind‐side muscle and peritoneal cavity, which showed 470–488 g of weight gain (KW, P < 0.001, N= 78, df = 3). Specific growth rates (%/d) did not differ significantly (P > 0.05) among control, blind‐side muscle, and peritoneal cavity groups. No significant (P > 0.05) difference in survival rate was found between treatment and control. The readability of PIT tags in all implanted positions was 100%. The average time spent tagging at each position was less than 30 sec. These results show that PIT tagging of olive flounder weighing approximately 500 g in the blind‐side muscle and peritoneal cavity is feasible and reliable with fewer negative effects on growth than observed on the eyed‐side muscle site trial.     

Tagging effects on three non-native fish species in England (Lepomis gibbosus, Pseudorasbora parva, Sander lucioperca) and of native Salmo trutta

Abstract –  To address the dearth of information on tagging effects and long-term survivorship of tagged fish in native and introduced species, laboratory and field investigations were undertaken on three non-native fish species (pumpkinseed Lepomis gibbosus ; topmouth gudgeon Pseudorasbora parva ; pikeperch Sander lucioperca ) tagged with coded-wire (CW), passive integrated transponder (PIT), radio (RT) telemetry and/or acoustic tags (AT), with survivorship of native brown trout ( Salmo trutta ) examined in the field. Laboratory results revealed high survivorship following tag attachment/insertion and resumption of feeding within 24–48 h of tagging (all mortalities could be attributed to an unrelated outbreak of fungal infection), with retention rates being high in both pumpkinseed and pikeperch but low in topmouth gudgeon (excluded from field studies). In the field, short-term post-operation survival was high in pikeperch, pumpkinseed and brown trout. In pumpkinseed and trout, 100% of RT fish survived a 24–30 day tracking study, with 60% and 80%, respectively, recaptured alive at least 3 months post-tagging. Of PIT tagged pumpkinseed, 44% were recaptured (after 6–18 months), with small-sized, CW-tagged fish (0.38 g weight) captured up to 1 year after tagging. In pikeperch, all AT fish except one (the smallest specimen) survived their full expected tracking period (i.e. tag life) – the single lost specimen survived at least half of its expected tracking period (i.e. 6 month battery life). Overall, the tagging methods used were highly effective in pumpkinseed and pikeperch, showing good retention and survival, but PIT tagging of topmouth gudgeon was plagued by low survivorship and tag rejection.     

The Effects of Biomass Density on Size Variability and Growth Performance of Juvenile Largemouth Bass,Micropterus salmoides,in a Semi‐closed Recirculating System

This study evaluated the effects of biomass density on size variability and growth performance of feed‐trained largemouth bass, Micropterus salmoides, fingerlings in a semi‐closed recirculating system for 60 d. Average individual body weight and length of fingerlings were 9.04 g and 9.07 cm, respectively. Experimental biomass densities were set at 15, 20, 25, 30, 35, and 40 kg/m³. Water temperature was adjusted to approximately 25 C and dissolved oxygen concentration was maintained above saturation. Fish were fed a formulated diet (42% protein) distributed by automatic feeders for 12 h daily. During the experiment, fingerlings actively fed and presented high survival rates (96.8–95.0%) at all densities. Growth performance of fingerlings was not affected by the biomass densities tested in this study (P < 0.05). The ranges of size distributions were similar among treatments, but more fingerlings were near the average size at lower biomass densities. Based on the results of this study, largemouth bass fingerlings were tolerant of high biomass density and a gross yield of 100–125 kg/m³ may be viable for largemouth bass reared in a semi‐closed recirculating system up to 30 g in weight.     

Evaluation of VI-alpha and PIT-tagging of the seahorse <Emphasis Type="Italic">Hippocampus abdominalis</Emphasis>

The suitability of visible implant alphanumeric (VI-alpha) and passive integrated transponder (PIT)-tagging to individually identify seahorses (Hippocampus abdominalis) was assessed in two trials. For each trial, 24 seahorses were tagged and mortality, growth, tag retention and tag visibility/readability assessed, together with 24 control seahorses, over a period of 3 months. For VI-alpha tagging, a single tag was inserted under the skin between the first two anterior lateral tail rings of the seahorses. There was no difference in final seahorse length, wet weight, or mean SGR in tagged seahorses, compared with control seahorses, after 3 months. Tag retention was 100%, as was survival, in both treatments. Tag detection with the naked eye was generally poor but improved using LED blue light. However, readability of tag codes was highly variable and insufficiently reliable for VI-alpha to be suitable for identification of individual seahorses. In PIT-tagged seahorses, a single FDX-B transponder was inserted into the abdominal cavity of seahorses. There was also no difference in final seahorse length, wet weight, or mean SGR, compared with control seahorses, after 3 months. Tag retention was also 100%, as was survival in both treatments. Readability of transponders was reliable and quick using a compact reader. PIT-tagging is considered suitable for individual identification of large H. abdominalis.     

NET-PEN CULTURE OF STRIPED BASS X WHITE BASS HYBRIDS IN ESTUARINE WATERS OF SOUTH CAROLINA: A PILOT STUDY1

In 1978 a cooperative pilot study was initiated by the Marine Resources Research Institute and DØMSEA Farms, Inc. to examine the feasibility of rearing striped bass (Morone saxatilis) x white bass (M. chrysops) hybrids to marketable pan-size in estuarine net-pens. The first study was begun in July 1978 when a total of 1,070 hybrid fingerlings (mean weight, 1.7 g) were stocked in 3.05 × 2.44 × 1.83 m deep net-pens moored to a commercial marina dock on the Stono River near Charleston, S.C. During the first month these fish suffered a 76% mortality, apparently as a result of feeding only a dry salmon ration. Thereafter, the remaining fish were fed the dry ration mixed approximately half-and-half with ground fish. At the end of one year, these fish had attained a mean weight of 523.0 g, with 74.6% survival. A second experiment was begun in July 1979 when 900 hybrid fingerlings (mean weight, 3.0 g) were stocked in each of three 3.05 × 2.44 × 1.83 m net-pens at the marina (stocking density, ?66 fish/m³). The fish were fed a mixture of dry salmon feed and ground fish throughout. At the end of one year, survival and weight averaged 88% and 310.2 g, respectively. Biomass in the pens at this time averaged 16 kg/m³. Little growth or active feeding occurred at temperatures < 15°C. In contrast, salinity variations had no apparent effect on growth. However, a period of decreasing salinity in early spring coincided with an outbreak of a bacterial disease (cf. Vibrio anguillarum) among striped bass fingerlings reared in adjacent pens. Fish which had been treated with a vaccine solution did not succumb to the disease, while approximately 50% mortality occurred among non-vaccinated fingerlings.     

Partial replacement of fish oil by flaxseed oil in Atlantic halibut (Hippoglossus hippoglossus L.) diets: effects on growth,nutritional and sensory quality

Three isonitrogenous (520 g protein kg^?1 DM) and isoenergetic (25 MJ kg^?1 DM) diets containing increasing levels of flaxseed oil (FxO; 0%, 40% and 70% of total added oil) at the expense of fish oil (FO) were tested for 33 weeks in groups of 61 individually PIT‐tagged halibut (initial weight, 849 ± 99 g). Effects on fish growth performance, fillet nutritional and sensory quality were determined. Specific growth rate (0.2% day^?1), feed conversion ratio (1.2–1.3) and nitrogen and energy retention were not affected by dietary treatments. Dietary fatty acid composition was reflected in fatty acid profiles of halibut muscle, liver and heart. Muscle of fish fed FxO diets contained higher 18:2n‐6 and 18:3n‐3 concentrations whereas 20:5n‐3 and 22:6n‐3 levels were significantly reduced. However, increasing FO replacement induced preferential retention of 22:6n‐3 especially in heart, and a trend for 20:5n‐3 conservation in heart and muscle was observed. FO replacement did not affect colour, texture and the characteristic fish odour and flavour of cooked fillets. By selectively retaining long‐chain polyunsaturated fatty acids halibut can adapt to a lower dietary supply without adverse effects on growth, feed conversion ratio, survival, and fillet nutritional and sensory quality.     

Effects of tagging on migration behaviour,survival and growth of hatchery‐reared Atlantic salmon smolts

The effects of four different tagging methods (PIT, anchor T‐tag, Carlin tag and dummy radio transmitter) on survival, behaviour and growth of Atlantic salmon smolts during their downstream migration were examined in semi‐natural circular channels during a natural migration period in spring. Survival of smolts was high and tagging wounds healed well in all tagging groups. Tag loss rates were generally low, being the highest (2.5%) in the dummy radio transmitter group. Total length and body mass of the tagged and untagged smolts did not differ at the end of the experiment. Migration activity of smolts generally showed similar patterns among the treatments. However, Carlin‐tagged smolts started their migration slightly later than the PIT‐tagged fish, and smolts tagged with Carlin tag or dummy radio transmitter showed less overall migration activity than fish with PIT tag.     

Evaluation of passive integrated transponder tags for marking the bullhead (Cottus gobio), a small benthic freshwater fish: effects on survival, growth and swimming capacity

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.     

Evaluation of two anaesthetic agents and the passive integrated transponder tagging system in Octopus vulgaris (Cuvier 1797)

Octopus vulgaris is a species of demand in the market with the potential to diversify European aquaculture. However, this species develops complex social interactions under culture conditions, which may have negative effects on its growth, survival and profitability. In order to understand its behaviour under such conditions, individual tagging systems allow a careful evaluation of biological parameters, such as growth and longevity. The present work describes a combined protocol (anaesthetic and tagging) for implanting subcutaneous passive integrated transponder tags (PIT). The effect of two anaesthetic agents in facilitating octopus handling is assessed: clove oil at 20–40–100 mg L^?1 and ethanol (96%) at 1–1.5–2%. The most suitable body location of PIT tags, its effect on growth and mortality, the addition of a stitch and the PIT retention rate after 2 months in floating cages were evaluated. It was concluded that immersion in seawater with 1.5% of ethanol at 22.3±0.5 °C is a suitable anaesthetic for this species. The results showed that the best‐selected PIT body location was the upper left arm III. No effect of the PIT tagging system was found on growth and survival when tagged and untagged octopuses were compared. It was observed after 2 months that the stitch did not induce an increase in the retention rate and 81–100% tag retention regardless of the dietary treatment.     

Effect of intraperitoneal passive implantable transponder (PIT) tags on the growth and survival of juvenile snapper, Pagrus auratus (Bloch and Schneider)

Abstract. This study examined whether passive implantable transponder (PIT) tags could be used to mark individually juvenile snapper, Pagrus auratus (Bloch and Schneider), without affecting their growth. Fifty juvenile snapper (25 tagged and 25 untagged controls) were placed in each of four 2000–1 tanks. At the start of the experiment the snapper had a mean weight of 59 ± 18g (SD). After 70 days, the mean weight of all fish was 115 ± 31 g (SD) and there was no significant difference between the growth of tagged and untagged fish. Apparent tag loss ranged from 4 to 8%.     

Production Characteristics of Striped Bass × White Bass and Striped Bass × Yellow Bass Hybrids

The potential for commercial culture of hybrid striped bass is promising in many areas of the United States. While several different striped bass hybrids are candidates for culture, differential performance has not been thoroughly evaluated. Comparative performance of two striped bass hybrids was evaluated in six, 757–1, fiberglass tanks receiving a continuous flow of ambient pond water for 397 d. Three replicate tanks were stocked with 50 fingerlings (66 fish/m³) of either striped bass female × white bass male (mean weight 23 g) or striped bass female × yellow bass male hybrids. Fish were fed a 35% protein ration throughout the study, and weight was recorded for all fish at stocking and at 21-d intervals. White bass hybrids grew significantly faster (0.94 g/d) than yellow bass hybrids (0.59 g/d). Survival to harvest averaged 65% and 44% for yellow bass and white bass hybrids, respectively. A significant difference from the expected 1:1 sex ratio occurred for yellow bass hybrids (100% female), but not for white bass hybrids (56% female). Mean condition factor, 1.63 and 1.39, and fillet percentage, 30.7% and 28.4%, was significantly higher for white bass hybrids compared to yellow bass hybrids.     

Effect of visible implant elastomers on the growth,survival and tag retention in juvenile Atlantic sturgeon (Acipenser oxyrinchus) in laboratory conditions

This study identifies the possibility of using visible implant elastomers (VIE) to tag juvenile Atlantic sturgeon (Acipenser oxyrinchus). The mean body weight was 2.4 ± 0.4 g, and mean body length 5.5 ± 0.5 cm. Markers in three colours were used: blue, orange and green. Implant elastomers were injected in the rostrum and in the tail shaft. The experiment was conducted over a period of 10 weeks and included also a control group, that is, no tagging. No significant effect of tagging on the specific growth rate, feed conversion ratio and condition factor of juvenile Atlantic sturgeon was observed. The fish in all groups increased their body weight more than 10 times, reaching body weight of 25–28 g. The final survival in all of the groups was approximately 40%. The final tag retention varied depending on the implant colour. The highest retention of 100% was obtained with orange VIE and was significantly different from blue and green. Tag retention was dependent on the place of marking (P > 0.05). A correlation was observed between the applied dye and the place of marking (P = 0.0166). The best results were obtained when marking with orange VIE in the rostrum as all markers were visible after 70 days even without the use of UV light. According to our research, marking with VIE does not negatively affect growth and survival of juvenile Atlantic sturgeon and can be recommended for fish with an initial body weight of approximately 2.5 g in the case of short‐term research.     

Total and available tryptophan requirement of Nile tilapia,Oreochromis niloticus,fingerlings

The dietary total and available requirement of tryptophan of Nile tilapia fingerlings was determined using linear regression analysis. Six hundred fish (3.4 ± 0.0 g) were fed diets containing 296.4 g/kg of crude protein and 14.1 MJ/kg of digestible energy. Five extruded diets containing 2.5, 3.0, 3.4, 3.8 and 4.2 g/kg of total tryptophan were evaluated. Fish were fed four times a day during 45 days. Final body weight, weight gain, feed intake, feed conversion ratio and net protein utilization of fish fed Trp 3.4 and Trp 3.8 diets were improved compared to fish fed Trp 2.5 and Trp 4.2 diets. No significant differences in survival rate, whole‐body moisture and ash were observed. Whole‐body amino acid profile of fish fed different diets did not differ statistically (p > .05). Fish fed Trp 3.0 and Trp 3.4 diets showed higher tryptophan retention compared to fish fed Trp 2.5 and Trp 4.2 diets. Excepting blood glucose, no effects of dietary tryptophan on haematological parameters were observed. The dietary total tryptophan requirement of Nile tilapia fingerlings based on weight gain was estimated to be 3.4 g/kg (11.0 g/kg of dietary crude protein) or 3.0 g/kg of available tryptophan (11.0 g/kg of dietary digestible protein).     

Feasibility of Pond Production of Largemouth Bass,Micropterus salmoides,for a Filet Market

The effects of stocking density on food‐size largemouth bass (LMB), Micropterus salmoides, production (>0.5 kg) were evaluated in a 2‐yr study by stocking LMB fingerlings (mean weight = 57 g/fish) in 0.1‐ha earthen ponds at rates of 6175, 12,350, or 18,525 fish/ha. Gross yields increased from 3989 to 9096 kg/ha as stocking density increased. No significant differences were observed in survival rates (range of 65–74%) due to density. Maximum feed consumption occurred at water temperatures of 27–30 C. Feed conversion ratio (FCR) and mean harvest weight were significantly different (P < 0.05) among densities, with the lowest FCR and the lowest mean weight found at the highest density (18,525 fish/ha). At harvest, LMB were considered to be in good condition with relative weight (W_r) values of 123–124. Dressout yield percentages were 61–62% for whole‐dressed LMB and 34–35% for shank filets. LMB grew well and reached a size adequate for targeted shank filet sizes. However, the production costs of $7.26–$9.34/kg mean that LMB production for a filet market is unlikely to be feasible. Research to lower LMB fingerling and feed costs and improved FCR would contribute to improved economic feasibility.     

Application of controlled-release,GnRHa-delivery systems in commercial production of white bass X striped bass hybrids (sunshine bass), using captive broodstocks

Hatchery-produced white bass (Morone chrysops) and striped bass (M. saxatilis) reared to maturity in a commercial aquaculture facility, were successfully spawned using controlled-release delivery systems containing the gonadotropin-releasing hormone analog DAla⁶, Pro⁹[NEt]-GnRH (GnRHa). Two-year-old white bass females (mean weight, 0.81 kg) were implanted with different polymer-based, GnRHa delivery systems at doses ranging from 40 to 89 μg GnRHa kg⁻¹ body weight. GnRHa treatment on 20 February 1994, when females contained oocytes up to 720 μm in diameter, induced ovulation of all fish between 35 to 82 h after treatment. The white bass eggs produced were fertilized with sperm from striped bass for the production of sunshine bass. An average of 294500 eggs kg⁻¹ were produced, with a mean fertility of 81.2%, 24 h survival of 46.5%, and overall hatching success of 45%. Survival from hatch to 30 days post-hatch was 78% and the fry weighed between 0.07 and 0.1 g. Overripening of eggs began within 1 h from ovulation and maximum fertilization (60%) was observed when eggs were stripped 0.5 h after ovulation. Fertilization success decreased thereafter to 31% and 10% by 1 h and 3 h after ovulation, respectively. Control fish not treated with GnRHa did not show any signs of final oocyte maturation during the period of the study. GnRHa administration via controlled-release delivery systems appears to be a very effective method for inducing high fecundity ovulation of captive white bass broodstocks, and producing eggs of high fertility and hatching success.