Surgical implantation of transmitters into fish

Although the Animal Welfare Act does not cover poikilotherms, individual institutions and policies and legal requirements other than the Animal Welfare Act (e.g., the US Public Health Service and the Interagency Research Animal Committee's Principles for the Utilization and Care of Vertebrate Animals Used in Testing, Research, and Training) require the review of projects involving fish by institutional animal care and use committees (IACUCs). IACUCs may, however, lack the knowledge and experience to evaluate fish projects judiciously, especially when the projects are in field settings. Surgeries involving implantation of transmitters and other instruments into the coelom, which now comprise a very common research tool in the study of free-ranging fishes, are examples of surgeries that use a broad spectrum of surgical and anesthetic techniques, some of which would not be considered acceptable for similar work on mammals. IACUCs should apply the standards they would expect to be used for surgeries on homeotherms to surgeries on fish. Surgeons should be carefully trained and experienced. Surgical instruments and transmitters should be sterile. Regulations and laws on the use of drugs in animals should be followed, particularly those concerned with anesthetics and antibiotics used on free-ranging fish. Exceptions to surgical procedures should be made only when circumstances are extreme enough to warrant the use of less than optimal procedures.     

Evaluation of water entry into the coelom and different levels of aseptic technique during surgical implantation of electronic tags in freshwater fish

We reviewed the literature in an attempt to determine the importance of aseptic technique when implanting electronic tags in fish. Given that there was negligible information on this topic we embarked on a study where bluegill (Lepomis macrochirus) were used as a model to investigate the effects of different aseptic surgical techniques for the intracoelomic implantation of electronic tags in fish. First we tested the effects of water entry into the incision using five treatments: lake, distilled and saline water introduced into the incision, water-free controls, and non-surgery controls. For fish in the water treatments, 1 mL of the sample was introduced into their coelom prior to incision closure. Fish were held for 10 days to monitor survival and at the end of the study, the survivors were blood sampled and euthanized to evaluate condition and health using the health assessment index. In a second experiment, four aseptic treatments were used: non-sterile, field-based, high-grade sterility, and non-surgery controls and fish were monitored as in the first experiment. For both experiments, no differences in physiological status, health or mortality were noted among treatment groups. However, in the aseptic techniques experiment, surgical times were approximately twice as long for fish in the sterile treatment as compared to other groups and the costs of surgical supplies was greater than that of the less-sterile treatments. Although we failed to document any benefit of keeping water out of the incision or using aseptic technique for bluegill, in other situations and for other species, such approaches may be important. As such, we encourage fish surgeons practicing intracoelomic implants to attempt to prevent water entry into the coelom. We also encourage, at least some level of infection control (e.g., non-sterile gloves, clean tags and surgical tools) consistent with good veterinary practices to maintain the welfare status of tagged fish and ensure that the data from tagged fish representative of untagged conspecifics. However, the most prudent and ethical approach would be to work with veterinarians to incorporate formal sterilization procedures, equipment (e.g., sterile gloves) and aseptic technique into field surgical techniques.     

Holding of juvenile salmonids for surgical implantation of electronic tags: a review and recommendations

Many telemetry-based studies require that fish be sampled from the wild and then held both prior to and after the implantation of an electronic tag. However, the effects of such holding (or the lack thereof) have yet to be studied intensively. Pre-surgical holding often occurs to facilitate logistical needs of research projects and as an attempt to minimize negative physiological effects due to capture and handling stress. Further, post-surgical holding time and conditions greatly influence the physiological state of fish prior to being returned to the wild. This paper reviews pertinent studies pertaining to the effects of surgical holding on the behavior, physiology, and survival of fishes, with particular emphasis on juvenile salmonids. The effects of individual aspects of surgical holding such as handling, water quality, light conditions, holding density, metabolic scope, and duration of holding are reviewed. Recommendations regarding certain aspects of surgical holding are offered with a goal of reducing bias related to the surgical process.     

An introduction to the practical and ethical perspectives on the need to advance and standardize the intracoelomic surgical implantation of electronic tags in fish

The intracoelomic surgical implantation of electronic tags (including radio and acoustic telemetry transmitters, passive integrated transponders and archival biologgers) is frequently used for conducting studies on fish. Electronic tagging studies provide information on the spatial ecology, behavior and survival of fish in marine and freshwater systems. However, any surgical procedure, particularly one where a laparotomy is performed and the coelomic cavity is opened, has the potential to alter the survival, behavior or condition of the animal which can impair welfare and introduce bias. Given that management, regulatory and conservation decisions are based on the assumption that fish implanted with electronic tags have similar fates and behavior relative to untagged conspecifics, it is critical to ensure that best surgical practices are being used. Also, the current lack of standardized surgical procedures and reporting of specific methodological details precludes cross-study and cross-year analyses which would further progress the field of fisheries science. This compilation of papers seeks to identify the best practices for the entire intracoelomic tagging procedure including pre- and post-operative care, anesthesia, wound closure, and use of antibiotics. Although there is a particular focus on salmonid smolts given the large body of literature available on that group, other life-stages and species of fish are discussed where there is sufficient knowledge. Additional papers explore the role of the veterinarian in fish surgeries, the need for minimal standards in the training of fish surgeons, providing a call for more complete and transparent procedures, and identifying trends in procedures and research needs. Collectively, this body of knowledge should help to improve data quality (including comparability and repeatability), enhance management and conservation strategies, and maintain the welfare status of tagged fish.     

Diving behaviour of jellyfish equipped with electronic tags

Jellyfish are one of the most abundant and conspicuous membersof our coastal marine fauna and are now known to play majortrophic roles in marine systems. However, little is known aboutthe movements and behaviour of individuals. We equipped individualcompass jellyfish (Chrysaora hysoscella) (n = 15) off the Dinglecoast, Ireland, with miniature time-depth recorders to log theirdepth over periods of a few hours. Vertical movements were extensive,with all jellyfish changing their depth during tracking. A rangeof vertical movements were seen including initial diving fromthe surface down to a maximum of 29.6 m after device attachment,some jellyfish remaining near the bottom, some moving up anddown in mid-water and some moving back near the surface. Theseresults show that jellyfish actively reposition themselves inthe water column over small time-scales and open the way formore extensive studies equipping jellyfish with electronic tags.     

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.     

Cytogenetic techniques in fish genetics

A modification of a previously described method of fish blood lymphocyte culture is described and discussed with the results of various chromosome banding protocols as applied to fish chromosomes.     

Surgical skin-marking techniques

Surgical skin-marking inks and dyes are in everyday use for designing and planning incisions in plastic and reconstructive surgery. We have traced the historical development of surgical skin-marking techniques from ancient times to the present. The biochemical characteristics of the commonly used marking agents are discussed. A three-part experiment utilizing a pig model was carried out to test the tissue inflammatory response to the various dyes and inks when used intradermally as tattoos, the persistence of such tattoos, and the ease of skin erasure for each of eight stains. Methylene blue and gentian violet are recommended as the best all-purpose marking agents. The use of proprietary inks is discouraged.     

Parasites as biological tags for stock discrimination in marine fish from South American Atlantic waters

The use of parasites as biological tags in population studies of marine fish in the south-western Atlantic has proved to be a successful tool for discriminating stocks for all species to which it has been applied, namely: Scomber japonicus, Engraulis anchoita, Merluccius hubbsi and Cynoscion guatucupa, the latter studied on a broader geographic scale, including samples from Uruguayan and Brazilian waters. The distribution patterns of marine parasites are determined mainly by temperature-salinity profiles and by their association with specific masses of water. Analyses of distribution patterns of some parasite species in relation to gradients in environmental (oceanographic) conditions showed that latitudinal gradients in parasite distribution are common in the study area, and are probably directly related to water temperature. Indeed, temperature, which is a good predictor of latitudinal gradients of richness and diversity of species, shows a latitudinal pattern in south-western Atlantic coasts, decreasing southwards, due to the influence of subtropical and subantarctic marine currents flowing along the edge of the continental slope. This pattern also determines the distribution of zooplankton, with a characteristic specific composition in different water masses. The gradient in the distribution of parasites determines differential compositions of their communities at different latitudes, which makes possible the identification of different stocks of their fish hosts. Other features of the host-parasite systems contributing to the success of the parasitological method are: (1) parasites identified as good biological tags (i.e. anisakids) are widely distributed in the local fauna; (2) many of these species show low specificity and use paratenic hosts; and (3) the structure of parasite communities are, to a certain degree, predictable in time and space.     

Parasites as biological tags in population studies of demersal and pelagic fish species

Among the different techniques applied in a holistic approach for fish stock identification, the use of parasites as "biological tags" is becoming increasingly important. In this presentation, our recent studies on the use of some parasite species, identified by genetic markers, and the parasite/fauna composition, in stock identification of demersal (Merluccius merluccius), small pelagic (Trachurus trachurus), and large pelagic fish species (Xiphias gladius) are reviewed. Different species of Anisakis and Hysterothylacium were genetically identified by the application of genetic (allozyme) markers. Statistically significant differences in the spatial distribution of distinct species of Anisakis were found in the fish considered. As to the species of Hysterothylacium genetically detected, different relative proportions were detected in several Mediterranean and Atlantic samples of swordfish (X. gladius). This study demonstrates the potential value of these anisakid nematodes, at both larval and adult stages, as "biological tags" for these fish species in European waters.     

转基因鱼的研究进展与商业化前景

转基因技术为鱼类育种开辟了新的途径。目前已培育出转生长激素基因鲤、鲑和罗非鱼,转荧光蛋白基因斑马鱼与唐鱼等可稳定遗传的转基因鱼品系,其中快长转生长激素基因鱼的获得对于提高水产养殖的产量与养殖效益具有十分重要的意义。文章简要综述了转基因鱼应用研究的成就、相关技术及生态安全方面的研究进展。显微注射仍是目前基因转植的常用方法,应用转座酶或巨核酸酶介导的转基因新技术可提高基因转植效率与整合率。转基因元件的选择应尽量考虑"全鱼"基因或"自源"基因,以减少转基因鱼食用安全方面的顾虑同时也有利于转植基因的表达与生理功效的发挥。生态安全是转基因鱼商用化面临的最大问题。虽然有研究显示转基因鱼与传统的选育鱼类相比适合度较差,但由于环境与基因型间的相互作用,根据实验室获得的转基因鱼对生态影响的结果,难以预测转基因鱼一旦逃逸会对自然水生态环境产生怎样的影响。因此应建立高度自然化的环境以获得可靠的数据客观评价生态风险,有效的物理拦截、不育化处理等生物学控制策略仍是保证转基因鱼安全应用的关键措施。     

Consensus statement for implantation and follow-up of cardiac implantable electronic devices in India

Cardiac implantable electronic device (CIED) procedures are being done by many operators/centers and it is projected that this therapy will remarkably increase in India in the coming years. This document by IHRS, aims at guiding the Indian medical community in the appropriate use and method of implantation with emphasis on implanter training and center preparedness to deliver a safe and effective therapy to patients with cardiac rhythm disorders and heart failure.     

Using parasites as biological tags of fish populations: A dynamical model

A simple model of macroparasitic infections has been used to evaluate the potential use of parasites as biological tags of fish populations. In the model, the parasite-host interaction is regulated by a birth-death process, and parasites can only be acquired by the non-specific migratory host population in a particular area of the space domain. In this case, we show that parasites can be succesfully used for stocks identification and to describe the migratory routes taken by some marine fish species.     

Hydrodynamic focusing and electronic cell-sizing techniques

The technique of hydrodynamic focusing, used to improve the resolution of the Coulter counter for the sizing of bacteria, was examined. Latex particles of 0.26 μm³ to 6.7 μm³ volume were used to examine the characteristics of the system with and without hydrodynamic focusing. The system then was evaluated for sizing mixed bacterial populations as well as single populations. Possible applications are also discussed.     

Local variability in metazoan parasites of the pelagic fish species, Engraulis ringens: implications for fish stock assessment using parasites as biological tags

Parasites have been used successfully as biological tags in population studies, mainly in marine fishes, but also in marine mammals, crustaceans and molluscs. Almost all published information dealing with parasites as biological tags evaluates differences between localities. However, local variability in the component community has not been assessed. In this work, we examined whether local variation of the metazoan parasite fauna of Engraulis ringens, extracted from five independent samples from two nearby localities in northern Chile, can be a factor causing bias in stock identification. Our results show that local variability, as estimated by a single sample, may suffice to represent component community variability with no need for replicated data.     

Random forests, a novel approach for discrimination of fish populations using parasites as biological tags

Due to the complexity of host-parasite relationships, discrimination between fish populations using parasites as biological tags is difficult. This study introduces, to our knowledge for the first time, random forests (RF) as a new modelling technique in the application of parasite community data as biological markers for population assignment of fish. This novel approach is applied to a dataset with a complex structure comprising 763 parasite infracommunities in population samples of Atlantic cod, Gadus morhua, from the spawning/feeding areas in five regions in the North East Atlantic (Baltic, Celtic, Irish and North seas and Icelandic waters). The learning behaviour of RF is evaluated in comparison with two other algorithms applied to class assignment problems, the linear discriminant function analysis (LDA) and artificial neural networks (ANN). The three algorithms are used to develop predictive models applying three cross-validation procedures in a series of experiments (252 models in total). The comparative approach to RF, LDA and ANN algorithms applied to the same datasets demonstrates the competitive potential of RF for developing predictive models since RF exhibited better accuracy of prediction and outperformed LDA and ANN in the assignment of fish to their regions of sampling using parasite community data. The comparative analyses and the validation experiment with a 'blind' sample confirmed that RF models performed more effectively with a large and diverse training set and a large number of variables. The discrimination results obtained for a migratory fish species with largely overlapping parasite communities reflects the high potential of RF for developing predictive models using data that are both complex and noisy, and indicates that it is a promising tool for parasite tag studies. Our results suggest that parasite community data can be used successfully to discriminate individual cod from the five different regions of the North East Atlantic studied using RF.     

Tracking invasive animals with electronic tags to assess risks and develop management strategies

Invasive species alter ecosystem structure and function when they establish in new habitats. Although preventing or managing invasions is extremely important for maintaining biodiversity, doing so is difficult and requires efficient intervention. Remote monitoring of free-living animals with electronic tags (i.e. tags that transmit data remotely or log them for future retrieval) can contribute important knowledge about invasive animal biology. A quantitative literature review identified instances in which electronic tagging has contributed to studying invasions. Electronic tags were generally used for one of four purposes: (1) characterize spatial ecology; (2) identify interactions; (3) assess risk potential; or (4) evaluate management options. Overall, electronic tags have considerable potential for developing, refining, and evaluating invasion management strategies that contribute to conservation efforts. We explore the role of electronic tags as a component of integrated control program design and implementation for invasive animals.     

Auricular reconstruction for microtia: Part II. Surgical techniques

Reconstruction of the microtic ear represents one of the most demanding challenges in reconstructive surgery. In this review the two most commonly used techniques for ear reconstruction, the Brent and Nagata techniques, are addressed in detail. Unique to this endeavor, the originator of each technique has been allowed to submit representative case material and to address the pros and cons of the other's technique. What follows is a detailed, insightful overview of microtia reconstruction, as a state of the art. The review then details commonly encountered problems in ear reconstruction and pertinent technical points. Finally, a glimpse into the future is offered with an accounting of the advances made in tissue engineering as this technology applies to auricular reconstruction.     

Development of genetic techniques for the psychrotrophic fish pathogen Flavobacterium psychrophilum

Flavobacterium psychrophilum, a member of the Cytophaga-Flavobacterium-Bacteroides group, is an important pathogen of salmonid fish. Previous attempts to develop genetic techniques for this fastidious, psychrotrophic bacterium have met with failure. Here we describe the development of techniques for the genetic manipulation of F. psychrophilum and the identification of plasmids, selectable markers, a reporter system, and a transposon that function in several isolates of this fish pathogen. The antibiotic resistance genes ermF, cfxA, and tetQ function in F. psychrophilum. Cloning vectors based on the F. psychrophilum cryptic plasmid pCP1 which carried these selectable markers were introduced by conjugation from E. coli, resulting in antibiotic-resistant colonies of F. psychrophilum. Conjugative transfer of DNA into F. psychrophilum was strain dependent. Efficient transfer was observed for two of the seven strains tested (THC02-90 and THC04-90). E. coli lacZY functioned in F. psychrophilum when expressed from a pCP1 promoter, allowing its development as a reporter for studies of gene expression. Plasmids isolated from F. psychrophilum were efficiently introduced into F. psychrophilum by electroporation, but plasmids isolated from E. coli were not suitable for transfer by this route, suggesting the presence of a restriction barrier. DNA isolated from F. psychrophilum was resistant to digestion by Sau3AI and BamHI, indicating that a Sau3AI-like restriction modification system may constitute part of this barrier. Tn4351 was introduced into F. psychrophilum from E. coli and transposed with apparent randomness, resulting in erythromycin-resistant colonies. The techniques developed in this study allow for genetic manipulation and analysis of this important fish pathogen.     

Efficacy of passive integrated transponder tags to determine spawning-site visitations by a tropical fish

Individual identification of organisms is a crucial part of assessing the processes that influence small-scale distribution patterns and the maintenance of social organizations. This study evaluates the use of passive integrated transponder (PIT) tags to quantify small-scale space use in a marine damselfish, Pomacentrus amboinensis (Pomacentridae). Implanting small PIT tags in the body cavity of fish down to 5.2 g with a hypodermic needle had no adverse effect on mortality or growth over a 47-day tank study. A 63-day field study also showed that tags had no influence on body condition as measured by Fultons condition factor (K), gonadosomatic indices, or plasma cortisol levels (a physiological indicator of stress). The utility of PIT-tag technology is illustrated by preliminary information from a study on the diel periodicity of visitations to male nest sites by female P. amboinensis. Information suggests that there is a strong periodicity in visitations. Females first entered the nest site at 03:20 h, with 88% of the total of 4 h 45 min that females spent within a single nest occurring prior to dawn. Despite this, 81% of the total visitations to the nest occurred after dawn, with most being very brief, averaging 17 s. No one female monopolized access to the nest, with nine females accounting for 90% of the time that females spent within the nest site. This methodology will be particularly useful in the study of activity rhythms, patch dynamics, and social interactions in a wide range of marine organisms.Communicated by: Ecological Editor P.F. Sale