Surgical implantation techniques for electronic tags in fish

Intracoelomic implantation of transmitters into fish requires making a surgical incision, incision closure, and other surgery related techniques; however, the tools and techniques used in the surgical process vary widely. We review the available literature and focus on tools and techniques used for conducting surgery on juvenile salmonids because of the large amount of research that is conducted on them. The use of sterilized surgical instruments properly selected for a given size of fish will minimize tissue damage and infection rates, and speed the wound healing of fish implanted with transmitters. For the implantation of transmitters into small fish, the optimal surgical methods include making an incision on the ventral midline along the linea alba (for studies under 1 month), protecting the viscera (by lifting the skin with forceps while creating the incision), and using absorbable monofilament suture with a small-swaged-on swaged-on tapered or reverse-cutting needle. Standardizing the implantation techniques to be used in a study involving particular species and age classes of fish will improve survival and transmitter retention while allowing for comparisons to be made among studies and across multiple years. This review should be useful for researchers working on juvenile salmonids and other sizes and species of fish.     

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.     

Systematic review and meta-analysis of PIT tagging effects on mortality and growth of juvenile salmonids

Reviews in Fish Biology and Fisheries - A systematic review and meta-analysis was conducted to evaluate the appropriate tag:fish size ratio when tagging juvenile salmonids (genera Oncorhynchus,...     

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.     

Habitat diversity and species diversity: testing the competition hypothesis with juvenile salmonids

I experimentally tested two predictions of the hypothesis that the positive relationship between habitat diversity and species diversity arises from a reduction in the negative effects of interspecific competition. By allowing species to partition habitat and avoid competition, habitat diversity should 1) facilitate the addition of an ecologically intermediate species into an existing community, and 2) reduce the negative effects of that species on existing members of the community. I tested these predictions with juveniles of three sympatric salmonid species: coho salmon ( Oncorhynchus kisutch ), steelhead trout ( O. mykiss ), and cutthroat trout ( O. clarki ), which in natural streams occupy deep low-velocity pools, shallow high-velocity riffles, and intermediate habitats, respectively. I introduced two (coho and steelhead) and three species communities into each of three artificial stream habitats: pools, riffles, and diverse. The results provide partial support for the predictions. Cutthroat trout grew fastest in the diverse stream habitat. Though habitat diversity did not eliminate the negative effects of competition, in the three species community coho and steelhead grew as fast in the diverse habitat as in either homogeneous habitat. The results are consistent with data on species number and evenness from natural communities, where variation along other niche axes confounds the relationship between habitat diversity, interspecific competition, and species diversity.     

Occupational biomechanics of the neck: a review and recommendations.

Musculoskeletal disorders of the neck are becoming a major concern in industry. Several studies reported the association of neck pain, discomfort, and symptoms with different occupations in industry. Thus, the main objective of this study is to review and evaluate biomechanical techniques used in analyzing the occupational factors leading to neck pain and disorders. Recommendations for future research are also discussed.     

Comprehensive passage (COMPASS) model: a model of downstream migration and survival of juvenile salmonids through a hydropower system

Migratory fish populations are impacted worldwide by river impoundments. Efforts to restore populations will benefit from a clear understanding of survival and migration process over a wide-range of river conditions. We developed a model that estimates travel time and survival of migrating juvenile salmonids (Oncorhynchus spp.) through the impounded Snake and Columbia rivers in the northwestern United States. The model allows users to examine the effects of river management scenarios, such as manipulations of river flow and spill, on salmonid survival. It has four major components: dam passage and survival, reservoir survival, fish travel time, and hydrological processes. The probability that fish pass through specific routes at a dam and route-specific survival probabilities were based on hydroacoustic, radio telemetry, PIT tag, and acoustic tag data. We related reservoir mortality rate (per day and per km) to river flow, water temperature, and percentage of fish passing through spillways and then fit the relationships to PIT-tag survival data. We related fish migration rate to water velocity, percentage of fish passing through spillways, and date in the season. We applied the model to two threatened “Evolutionarily Significant Units” (as defined under the US Endangered Species Act): Snake River spring/summer Chinook salmon (O. tshawytscha Walbaum) and Snake River steelhead (O. mykiss Walbaum). A sensitivity analysis demonstrated that for both species survival through the hydropower system was responsive to water temperature, river flow, and spill proportion. The two species, however, exhibited different patterns in their response. Such information is crucial for managers to effectively restore migratory fish populations in regulated rivers. Guest editors: R. L. Welcomme & G. Marmulla Hydropower, Flood Control and Water Abstraction: Implications for Fish and Fisheries     

A quantitative assay for the juvenile hormones and their precursors using fluorescent tags

Background

The juvenile hormones (JHs) are sesquiterpenoid compounds that play a central role in insect reproduction, development and behavior. The lipophilic nature of JHs and their precursors, in conjunction with their low concentration in tissues and susceptibility to degradation had made their quantification difficult. A variety of methods exist for JH quantification but few can quantify on the femtomole range. Currently applied methods are expensive and time consuming. In the present study we sought to develop a novel method for accurate detection and quantification of JHs and their precursors.

Methods

A sensitive and robust method was developed to quantify the precursor, farnesoic acid (FA) and juvenile hormone III (JH III) in biological samples. The assay is based on the derivatization of analytes with fluorescent tags, with subsequent analysis by reverse phase high performance liquid chromatography coupled to a fluorescent detector (HPLC-FD). The carboxyl group of FA was derivatized with 4-Acetamido-7-mercapto-2,1,3-benzoxadiazole (AABD-SH). Tagging the epoxide group of JH III required a two-step reaction: the opening of the epoxide ring with sodium sulfide and derivatization with the fluorescent tag 4-(N,N-Dimethylaminosulfonyl)-7-(N-chloroformylmethyl-N-methylamino)-2,1,3-benzoxadiazole (DBD-COCl).

Conclusions

The method developed in the present study showed high sensitivity, accuracy and reproducibility. Linear responses were obtained over the range of 10–20 to 1000 fmols. Recovery efficiencies were over 90% for JH III and 98% for FA with excellent reproducibility.

Significance

The proposed method is applicable when sensitive detection and accurate quantification of limited amount of sample is needed. Examples include corpora allata, hemolymph and whole body of female adult Aedes aegypti and whole body Drosophila melanogaster. A variety of additional functional groups can be targeted to add fluorescent tags to the remaining JH III precursors.     

Evolution of fighting behavior under asymmetric competition: an experimental test with juvenile salmonids

Large-dominant and small-subordinate species engaging in asymmetricinterference competition may optimize behavior under differenttrade-offs between the chance of winning and the cost of fighting.If fighting behavior is heritable and under selection, theorysuggests that large-dominant and small-subordinate species shouldevolve aggressive and passive fighting behaviors, respectively.To test this prediction, I manipulated the size and competitiveasymmetry of juveniles from sympatric populations of large-dominantcoho salmon (Oncorhynchus kisutch) and small-subordinate steelheadtrout (O. mykiss) and asked whether differences in fightingbehavior persisted independently of competitive ability. I observedfighting behavior during dyadic contests in two habitats, mutuallypreferred pools and energetically demanding riffles, under eachof three size treatments: natural size asymmetry, asymmetryremoved, and reversed size asymmetry. The results supportedthe prediction. Competitive ability depended primarily on size;large individuals of both species dominated smaller heterospecifics,and neither species dominated when size matched. Fighting behaviordepended primarily on species identity; coho salmon used a higherproportion of aggressive chases, whereas steelhead trout useda higher proportion of passive displays. Large individuals weremore likely to chase, and small individuals were more likelyto display. As evidence that asymmetric competition is associatedwith behavioral divergence, these results complement previouswork on morphological divergence under asymmetric competitionand provide a richer context for other features of the coho–steelheadsystem.     

Recombinant protein expression and purification: a comprehensive review of affinity tags and microbial applications

Protein fusion tags are indispensible tools used to improve recombinant protein expression yields, enable protein purification, and accelerate the characterization of protein structure and function. Solubility-enhancing tags, genetically engineered epitopes, and recombinant endoproteases have resulted in a versatile array of combinatorial elements that facilitate protein detection and purification in microbial hosts. In this comprehensive review, we evaluate the most frequently used solubility-enhancing and affinity tags. Furthermore, we provide summaries of well-characterized purification strategies that have been used to increase product yields and have widespread application in many areas of biotechnology including drug discovery, therapeutics, and pharmacology. This review serves as an excellent literature reference for those working on protein fusion tags.     

The diversity of juvenile salmonids does not affect their competitive impact on a native galaxiid

We used an invaded stream fish community in southern Chile to experimentally test whether the diversity of exotic species affects their competitive impact on a native species. In artificial enclosures an established invasive, rainbow trout, Oncorhynchus mykiss, and a potential invader, Atlantic salmon, Salmo salar, reduced the growth rate of native peladilla, Aplochiton zebra, by the same amount. In enclosures with both exotic salmonids, the growth rates of all three species were the same as in single exotic treatments. While neither species identity nor diversity appeared to affect competitive interactions in this experiment, the impact of salmonid diversity may vary with the type of interspecific interaction and/or the species identity of the exotics. Our experiment links two prominent concepts in invasion biology by testing whether the result of invasional meltdown, an increase in the diversity of exotic species, affects their impact through interspecific competition, the mechanism invoked by the biotic resistance hypothesis.     

Response of downstream migrant juvenile Pacific salmonids to accelerating flow and overhead cover

Mechanical structures designed to divert or guide juvenile migrant salmon at dams often work less effectively than expected. This likely results from a lack of understanding of fish behaviour. In order to address this, a series of experiments was conducted at McNary dam, USA, to assess the influence of hydraulic transition and overhead cover on the behaviour of seaward migrating juvenile Pacific salmon. Fish passing through a flume encountered a choice of route that varied based on hydraulic factors and overhead cover. Direct observation revealed that individuals elicited strong avoidance behaviour when they encountered areas where hydraulic conditions changed rapidly or were covered. Our findings have implications relevant to fish pass design and culvert restoration in Europe. Critically, improvement of current fish pass design and development of alternative mechanisms that effectively block fish access to, and divert fish away from poor passage routes, requires consideration of the behavioural component of fish migration. Guest editors: R. L. Welcomme & G. Marmulla Hydropower, Flood Control and Water Abstraction: Implications for Fish and Fisheries     

The biological effects of radiofrequency radiation: a critical review and recommendations

Exposure of the general public and in particular certain occupational groups to radiofrequency radiation (RFR) is ubiquitous and of growing concern. No clear and widely accepted understanding of the biological effects and health implications of such RFR exposure has emerged. This paper reviews the data available, including reports of RFR effects on single cells or cell components, on genetic composition or development, on developed organs, tissues, or cell systems, and on integrative and regulatory biological systems. Reports of RFR effects on the immunological system, with consideration of the influence of neuroendocrine responses, are critically reviewed in greater detail to illustrate important points regarding data acquisition and assessment, and understanding and application of the RFR bioeffects literature in general. Factors affecting RFR bioeffects research are reviewed, and recommendations for future studies are provided.     

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.     

Predation by hatchery yearling salmonids on wild subyearling salmonids in the freshwater environment: A review of studies,two case histories,and implications for management

We conducted a literature review on predation by hatchery yearling salmonids on wild subyearling salmonids in the western United States. The review included 14 studies from the Pacific Northwest and California. In most instances, predation by hatchery yearling salmonids on wild subyearling salmonids occurred at low levels. However, when multiple factors contributing to the incidence of predation were met, localized areas of heavy predation were noted. Total prey consumed ranged from 456 to 111 000 subyearlings for the few studies in which enough information was gathered to make the estimate. We examined two of these studies in more detail: one detecting relatively low predation in four western Washington rivers and one detecting relatively high predation in the Trinity River in northern California. In the case of the rivers in western Washington, over 70% of wild subyearlings had migrated by the time hatchery steelhead were planted and those remaining had grown large enough to reduce their vulnerability to predation. In the case of the Trinity River, less than 20% of wild subyearlings had migrated by the time hatchery steelhead were planted and most were small enough to remain highly vulnerable to predation. We found that managers can effectively minimize the predation rate of hatchery yearling salmonids by reducing the spatial or temporal overlap of predator and prey. Unknown is the extent to which low predation rates, which likely occur in most places hatchery yearlings are released, might still negatively impact prey populations that are at low abundance because of other anthropogenic factors.     

Life cycle assessment at nanoscale: review and recommendations

Purpose  

The need for a systematic evaluation of the human and environmental impacts of engineered nanomaterials (ENMs) has been widely recognized, and a growing body of literature is available endorsing life cycle assessment (LCA) as a valid tool for the same. The purpose of this study is to evaluate how the nano-specific environmental assessments are being done within the existing framework of life cycle inventory and impact assessment and whether these frameworks are valid and/or whether they can be modified for nano-evaluations.     

Detection of conspecific alarm cues by juvenile salmonids under neutral and weakly acidic conditions: laboratory and field tests

A variety of fishes possess damage-released chemical alarm cues, which play a critical role in the detection and avoidance of potential predation threats. Recently, we have demonstrated that the ability of fathead minnows (Pimephales promelas) and finescale dace (Phoxinus neogaeus) to detect and respond to conspecific alarm cues is significantly reduced under weakly acidic conditions (pH 6.0). Rainbow trout (Oncorhynchus mykiss) and brook charr (Salvelinus fontinalis) possess an analogous alarm cue system. However, it is unknown if the trout alarm cue system is likewise affected by relatively small changes in pH. In addition, previous studies have not verified this phenomenon under natural conditions. We conducted laboratory and field trials to examine the potential effects of acute exposure to weakly acidic (pH 6.0) conditions on the detection and response of conspecific alarm cues by juvenile trout. Our laboratory results demonstrate that while juvenile rainbow trout exhibit significant increases in antipredator behaviour under normal pH conditions (pH 7.0–7.2), they do not respond to the presence of conspecific chemical alarm cues (i.e. response is not different from controls) under weakly acidic conditions. Similarly, a wild strain of brook charr in their natural streams near Sudbury, Ontario, failed to detect conspecific alarm cues in a weakly acidic stream (mean pH 6.11) while they responded to these cues in a neutral stream (mean pH of 6.88). This is the first demonstration that relatively small changes in ambient pH can influence alarm responses under natural conditions. These data suggest significant, sub-lethal effects of acid precipitation on natural waterways.