实验用鱼遗传质量控制及标准化

在遗传学及其他生命科学研究领域, 实验用鱼已成为一类应用越来越广的实验动物, 但是尚缺少标准化的质量控制标准和监管。在我国, 实验动物实行严格的许可证制度和质量监督制度。实验用鱼遗传质量控制标准是实验用鱼质量控制的基础。为了规范实验用鱼的遗传质量, 避免实验用鱼种质退化、遗传漂移, 导致实验结果误差, 开展了本标准的研究。依据《实验动物管理条例》, 参考国内外实验用鱼遗传学相关的研究成果, 结合我国实验用鱼生产和使用的实际情况, 在全面收集、分析实验数据和广泛征询专家意见的基础上, 以实验用斑马鱼和剑尾鱼遗传质量控制为规范对象, 研究制定了实验用鱼遗传质量控制标准, 供科研工作者参考、讨论。本标准对实验用斑马鱼和剑尾鱼的遗传分类及命名原则、实验用鱼的繁殖方法、近交系和封闭群的遗传质量监测进行了规范。新标准将为实验用鱼的使用和管理提供理论支撑。     

Guidance on the severity classification of scientific procedures involving fish: report of a Working Group appointed by the Norwegian Consensus-Platform for the Replacement, Reduction and Refinement of animal experiments (Norecopa)

The severity classification of procedures using animals is an important tool to help focus the implementation of refinement and to assist in reporting the application of the 3Rs (replacement, reduction and refinement). The recently revised Directive that regulates animal research and testing within the European Union requires Member States to ensure that all procedures are classified as 'non-recovery', 'mild', 'moderate' or 'severe', using assignment criteria set out by the European Commission (EC). However, these are focused upon terrestrial species, so are of limited relevance to fish users. A Working Group set up by the Norwegian Consensus-Platform for the 3Rs (Norecopa) has produced guidance on the classification of severity in scientific procedures involving fish, including examples of 'subthreshold', 'mild', 'moderate', 'severe' and 'upper threshold' procedures. The aims are to complement the EC guidelines and help to ensure that suffering in fish is effectively predicted and minimized. Norecopa has established a website (www.norecopa.no/categories) where more information on severity classification for procedures using fish, including field research, will be made available.     

The role of trait‐based approaches in understanding stream fish assemblages

1. The use of trait‐based approaches to examine the ecology of stream fish assemblages is increasing. However, selection of traits that will be useful in testing spatial or temporal hypotheses about ecological organisation is currently limited by availability of data, rather than empirical evaluation. 2. We analysed two data sets of stream fish assemblages to compare taxonomy and trait‐based approaches. The Wabash River temporal data set is based on 25 years of boat electrofishing collections over a 230‐km river distance. The Indiana Department of Environmental Management data set of stream collections in the state of Indiana was selected to represent a spatial database. We compared several trait‐based approaches: reproductive guilds, life history variables, biomonitoring metrics, ecosystem‐based functional guilds and feeding and ecosystem interaction guilds. 3. Analyses of fish assemblages that are designed to detect how environmental variation structures fish assemblages can expect similar results using taxonomic or trait‐based approaches. Results of trait‐based approaches will vary according to the spatial extent of the region and the number of unique entities of trait groups for a given data set. However, taxonomic analyses accounted for more variation than any trait‐based analyses.     

Righty fish are hooked on the right side of their mouths - observations from an angling experiment with largemouth bass, Micropterus salmoides

The development of muscles and bones in fish is laterally asymmetric (laterality). A "lefty" individual has a "C"-shaped body, with its left-side muscles more developed and the left side of its head facing forward. The body of a "righty" is the mirror-image. This laterality causes asymmetric interactions between individuals of different fish species, in that a righty or lefty fish consumes more lefty or righty fish, respectively. To investigate the coupling mechanisms between body asymmetry and predatory behavior, we conducted angling experiments with largemouth bass (Micropterus salmoides). We used the position of the fishhook set in the mouth to indicate the movement direction of the fish when it took the bait. Righty fish had more hooks set on the right side, whereas lefty fish had more on the left side, indicating that righty fish moved more to the left, and lefty fish moved more to the right, in successful catches. The relationship between the hooked position and movement direction was confirmed by video-image analysis of the angling.     

Distribution of fish in the river system of the Lower Irtysh

We report the results of investigation of fish distribution in water bodies of different types (open floodplain complex, closed lake, floodplain channels, and a riverbed depression) of the river system of the Lower Irtysh obtained by application of differently aimed hydroacoustic complexes and by traditional ichthyological methods. Distribution, composition, and abundance of fish aggregations and their diurnal movements are determined in different water areas. Periodicity, range, and direction of fish migrations, rhythm of downstream migrations of juveniles under various conditions are recorded. Distribution of fish is considered as a continual process controlling the biological integrity of the river system. Significant presence of nomadity (various migrations and local movements) is demonstrated in fish, reflecting multilevel lability of the environment in the floodplain-channel system of the Lower Irtysh. A set of notions is suggested defining application limits of principal terms characterizing fish movements of various scales: migrations, wanderings, and short-term movements.     

Ionic regulation in fish: the influence of acclimation temperature on plasma composition and apparent set points

Published data on the influence of acclimation temperature on normal ionic concentrations in fish plasma are summarized. Although osmolality rises near 0 degree C in many marine fish, there is otherwise no general tendency in marine species for osmolality, Na and Cl to fall with increasing temperature. The suggestion that osmolality, Na and Cl in freshwater fish typically fall with decreasing temperature is not supported. K and Ca generally rise with increasing temperature, or stay constant. Mg generally falls with increasing temperature, or stays constant. Evidence on concomitant variations in set points is sparse, but apparent set points for osmolality/Na/Cl, except near 0 degree C, usually vary by less than +/- 2% degrees C-1.     

Migratory benthic fishes may induce regime shifts in a tropical floodplain pond

1. Alternative states are a widely recorded phenomenon in shallow lakes, which may shift between turbid‐ and clear‐water conditions. Here, we investigate whether such shifts in a tropical floodplain pond may be related to the effect of the flood pulse regime on the community structures of fish and macrophytes. 2. Using a long‐term data set, we demonstrate how benthic fish migration together with colonisation by submerged plants affected the transition from a turbid to a macrophyte‐dominated state in a floodplain pond without top‐down control. 3. In our study, the turbid state occurred mostly during low water phases and was largely characterised by high values for the biomass of benthic fish, chlorophyll‐a and total phosphorous. 4. During the period of rising water levels, the migration of benthic fish out of the pond occurs simultaneously with the establishment of submerged plants, while water turbidity decreases along with phytoplankton and nutrient concentrations, inducing a clear‐water phase. However, when submerged plants are absent and fish migration is low, a transient state is generated. 5. We suggest that, in contrast to temperate ponds and shallow lakes, where the main driving mechanisms establishing alternative states are related to cascading effects via the food chain, in tropical ponds and shallow lakes it is resuspension of sediments by benthic fish that plays the most significant role in establishing alternative states. However, the effect of the flood pulse regime plays an important role in the temporal dynamics of fish community structure by controlling benthic fish migration.     

Species composition,abundance and diversity of Ichthyofauna of Ikere-Gorge,Oyo State,Nigeria

Anthropogenic activities in inland water can cause species loss and displacement. Therefore, there is a need to regularly examine species composition, abundance and diversity of freshwater ecosystem as a means to monitor its health. Ichthyofauna of Ikere-gorge, Iseyin, Oyo State was studied for a period of 24 month, from January 2017 to December 2018. Ikere-gorge was divided into four strata, each comprises three fishing villages. One village in each stratum was randomly selected as sampling site. The catches were sorted into taxonomic groups (species and families) using standard fish identification keys. Forty-one fish species from 13 families were identified in which species richness varied among the sampling villages. Asamu had 34, Agatu had 30, Spillway had 39 and Irawote had 29 species. The freshwater fish species of Nigeria is the richest in West Africa and more than 15% of these fish species are found in Ikere-gorge. Mormyridae family was the most represented with 10 species. Cichlidae was the most abundant by catch and by weight. Sarotherodon galilaeus has the highest abundance by catch and by weight. Gnathonemus brucii was identified as a vulnerable species. The result obtained from this study show that conservation program should be urgently put in place to prevent some fish from extinction. There should be introduction of closed season to allow for proper recruitment of fish population. Likewise, minimum mesh size should be set to allow juvenile and immature fish to escape and allow them to spawn at least once before being vulnerable to gear. There should regulation to set maximum number of fishermen to be allowed to fish at a particular day, this is to reduce fishing pressure.     

菱湖鱼病工作站:现代科学改造中国传统养鱼业的序曲

1953年,为帮助菱湖鱼农解决鱼病问题,中国科学院水生生物研究所在浙江省吴兴县菱湖镇建立了中国第一个鱼病工作站。自1953年5月成立至1956年3月撤离菱湖的近3年间,以倪达书为站长的菱湖鱼病工作站科研人员以四大家鱼为主要对象,在菱湖及周边养鱼区开展了鱼病病原调查、防治试验和门诊,在病原的分类鉴定和有效杀灭药物的筛选等方面取得了较大进展,对十几种流行广、危害大的主要鱼病,结合群众养鱼经验并通过试验研究,找到了有一定疗效的药物和治疗方法,总结出一套比较完整的防病养鱼措施并向全国推广,改变了当地鱼农"鱼病不能治"的保守观念,同时还为浙江省和全国各地鱼区培养了大批鱼病防治干部。菱湖鱼病工作站确立了中国鱼病防治的良好传统,开创了中国的鱼病学科,奠定了中国鱼病学基础,并为国内培养了众多鱼病防治人才,可谓现代科学改造中国传统养鱼业的序曲。     

A probabilistic model characterizing fish assemblages of French rivers: a framework for environmental assessment

1. Management of running waters and assessment of water quality trends require the use of biological methods. Among potential indicators, fish assemblages are of particular interest because of their ability to integrate environmental variability at different spatial scales. 2. The French Water Agencies and the Ministry of the Environment initiated a research programme to develop a fish-based index that would be applicable nation-wide. Such an index should encompass the relative importance of geographic, ecoregional and local factors influencing the distribution of riverine fishes. 3. An effective way of using the information available from fish assemblages to establish such an index is through the use of the 'reference condition approach' which involves testing a fish assemblage exposed to a potential stress against a reference condition that is unexposed to such a stress. 4. Logistic regression procedures were applied, using a fish data set of 650 reference sites fairly evenly distributed across French rivers and defined by some easily measured regional and local characteristics, to elaborate the simplest possible response model that adequately explains the observed patterns of occurrence for each species of a fish assemblage at a given site of any given river. This allows us to predict a 'theoretical' assemblage at a site. 5. The models were validated using a second independent data set of 88 reference sites. Using a third data set of 88 disturbed sites, the observed assemblages were then compared against the reference condition as defined by the 'theoretical' assemblages. The amount of deviation between the expected and observed assemblages within these sites is used as a measure of degradation. 6. This approach could be used as a framework for adapting and calibrating a multimetric index, thereby serving as a practical technical reference for conducting cost-effective biological assessments of lotic systems.     

Principles for linking fish habitat to fisheries management and conservation

A set of eight simple ecological and social principles is proposed that could enhance the understanding of what constitutes fish 'habitat' and, if implemented, could contribute to improved management and conservation strategies. The habitat principles are a small, interrelated sub‐set that may be coupled with additional ones to formulate comprehensive guidelines for management and conservation strategies. It is proposed that: 1) habitat can be created by keystone species and interactions among species; 2) the productivity of aquatic and riparian habitat is interlinked by reciprocal exchanges of material; 3) the riparian zone is fish habitat; 4) fishless headwater streams are inseparable from fish‐bearing rivers downstream; 5) habitats can be coupled – in rivers, lakes, estuaries and oceans, and in time; 6) habitats change over hours to centuries; 7) fish production is dynamic due to biocomplexity, in species and in habitats; 8) management and conservation strategies must evolve in response to present conditions, but especially to the anticipated future. It is contended that the long‐term resilience of native fish communities in catchments shared by humans depends on incorporating these principles into management and conservation strategies. Further, traditional strategies poorly reflect the dynamic nature of habitat, the true extent of habitat, or the intrinsic complexity in societal perspectives. Forward‐thinking fish management and conservation plans view habitat as more than water. They are multilayered, ranging from pools to catchments to ecoregions, and from hours to seasons to centuries. They embrace, as a fundamental premise, that habitat evolves through both natural and anthropogenic processes, and that patterns of change may be as important as other habitat attributes.     

Partial sequencing of sodA gene and its application to identification of Streptococcus dysgalactiae subsp. dysgalactiae isolated from farmed fish

AIMS: To investigate the difference between Lancefield group C Streptococcus dysgalactiae (GCSD) strains isolated from diseased fish and animals by sequencing and phylogenetic analysis of the sodA gene. METHODS AND RESULTS: The sodA gene of Strep. dysgalactiae strains isolated from fish and animals were amplified and its nucleotide sequences were determined. Although 100% sequence identity was observed among fish GCSD strains, the determined sequences from animal isolates showed variations against fish isolate sequences. Thus, all fish GCSD strains were clearly separated from the GCSD strains of other origin by using phylogenetic tree analysis. In addition, the original primer set was designed based on the determined sequences for specifically amplify the sodA gene of fish GCSD strains. The primer set yield amplification products from only fish GCSD strains. CONCLUSIONS: By sequencing analysis of the sodA gene, the genetic divergence between Strep. dysgalactiae strains isolated from fish and mammals was demonstrated. Moreover, an original oligonucletide primer set, which could simply detect the genotype of fish GCSD strains was designed. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that Strep. dysgalactiae isolated from diseased fish could be distinguished from conventional GCSD strains by the difference in the sequence of the sodA gene.     

Integration of chromosome set manipulation and transgenic technologies for fishes.

Chromosome set manipulation techniques have significant implications for research of transgenic fish. Gynogenesis can be used to generate isogenic lines, to map genes in relation to their centromeres, and to produce fish carrying extra chromosome fragments of foreign origin. Androgenesis can be used to produce isogenic lines and to recover strains from cryopreserved sperm. Triploidy can be induced in fish with heat or pressure treatment of fertilized eggs and by crossing tetraploid individuals with normal diploids. Triploid fish are typically effectively sterile. Triploid interspecific hybrids are usually more viable than the corresponding diploid hybrids. Given concerns about potential reproduction of transgenic fish in the wild, induced triploidy could facilitate application of transgenic technologies in some situations.     

A new fish horizon from the Maltese Miocene and its palaeoecological significance

Hitherto undescribed strata containing well-preserved fish occur at the base of the Tortonian, Upper Coralline Limestone Formation at Il Fawwara, Malta. The major elements of the fish fauna are Bregmaceros albyi, Syngnathus sp.a sciaenid and indeterminate members of the Percoidei. Collectively these fish are considered to represent part of a shallow marine assemblage tolerant to both sedimentation and salinity fluctuations.Detailed work on the associated fossils and sediments leads to the conclusion that this bed accumulated during a brief interval when shallow water sediments and biota were intermittently carried into a small shelf depression by a succession of density flows. Evidence is presented to suggest that these flows were set in motion by periodic storm activity affecting shallow water areas adjacent to a carbonate coastline of low relief.     

Training considerations for the intracoelomic implantation of electronic tags in fish with a summary of common surgical errors

Training is a fundamental part of all scientific and technical disciplines. This is particularly true for all types of surgeons. For surgical procedures, a number of skills are necessary to reduce mistakes. Trainees must learn an extensive yet standardized set of problem-solving and technical skills to handle challenges as they arise. There are currently no guidelines or consistent training methods for those intending to implant electronic tags in fish; this is surprising, considering documented cases of negative consequences of fish surgeries and information from studies having empirically tested fish surgical techniques. Learning how to do fish surgery once is insufficient for ensuring the maintenance or improvement of surgical skill. Assessment of surgical skills is rarely incorporated into training, and is needed. Evaluation provides useful feedback that guides future learning, fosters habits of self-reflection and self-remediation, and promotes access to advanced training. Veterinary professionals should be involved in aspects of training to monitor basic surgical principles. We identified attributes related to knowledge, understanding, and skill that surgeons must demonstrate prior to performing fish surgery including a “hands-on” assessment using live fish. Included is a summary of common problems encountered by fish surgeons. We conclude by presenting core competencies that should be required as well as outlining a 3-day curriculum for training surgeons to conduct intracoelomic implantation of electronic tags. This curriculum could be offered through professional fisheries societies as professional development courses.     

A simple electronic smolt counter

The development of methods for the automatic counting of migratory fish has become a matter of some importance in the United Kingdom and elsewhere, owing to the increasing concern over the lack of accurate information about fish stocks. An instrument capable of counting fish accurately and reliably in a variety of conditions remains a goal towards which progress is being made only slowly, despite strenuous efforts by a number of organizations.
The fish counters available at present are expensive to buy and sufficiently complex to be difficult to build by the majority of workers in fisheries management, but there are, however, circumstances where fish may be counted by relatively simple means and an example of this is given below.
It was found that salmon smolts swimming down a channel or tube could be reliably detected using a simple electronic circuit which was sensitive both to changes in resistance across 2 electrodes set in the water flow, and to the rate of change of resistance. These changes were amplified sufficiently to produce deflections on a recording meter so that subsequent examination of the chart gave both a count of the smolts and also the time of passage.
Details of the circuit, which can be built at low cost and with only elementary equipment, are discussed briefly and some of the results are given.     

Comparable disparity in the appendicular skeleton across the fish–tetrapod transition,and the morphological gap between fish and tetrapod postcrania

Appendicular skeletal traits are used to quantify changes in morphological disparity and morphospace occupation across the fish–tetrapod transition and to explore the informativeness of different data partitions in phylogeny reconstruction. Anterior appendicular data yield trees that differ little from those built from the full character set, whilst posterior appendicular data result in considerable loss of phylogenetic resolution and tree branch rearrangements. Overall, there is a significant incongruence in the signals associated with pectoral and pelvic data. The appendicular skeletons of fish and tetrapods attain similar levels of morphological disparity (at least when data are rarefied at the maximum sample size for fish in our study) and occupy similarly sized regions of morphospace. However, fish appear more dispersed in morphospace than tetrapods do. All taxa show a heterogeneous distribution in morphospace, and there is a clear separation between fish and tetrapods despite the presence of several evolutionarily intermediate taxa.     

Coral–algal phase shifts alter fish communities and reduce fisheries production

Anthropogenic stress has been shown to reduce coral coverage in ecosystems all over the world. A phase shift towards an algae‐dominated system may accompany coral loss. In this case, the composition of the reef‐associated fish assemblage will change and human communities relying on reef fisheries for income and food security may be negatively impacted. We present a case study based on the Raja Ampat Archipelago in Eastern Indonesia. Using a dynamic food web model, we simulate the loss of coral reefs with accompanied transition towards an algae‐dominated state and quantify the likely change in fish populations and fisheries productivity. One set of simulations represents extreme scenarios, including 100% loss of coral. In this experiment, ecosystem changes are driven by coral loss itself and a degree of habitat dependency by reef fish is assumed. An alternative simulation is presented without assumed habitat dependency, where changes to the ecosystem are driven by historical observations of reef fish communities when coral is lost. The coral–algal phase shift results in reduced biodiversity and ecosystem maturity. Relative increases in the biomass of small‐bodied fish species mean higher productivity on reefs overall, but much reduced landings of traditionally targeted species.     

Comparing Vectors of Adjusted Means when Covariance Matrices are Unequal

The ability to distinguish between stocks of fish is of vital importance in fisheries management programs. Morphometric measurements are commonly employed to separate biological populations. Unique role of multivariate analysis of covariance in separating fish stocks has been recognized recently. However, fish populations frequently differ in their covariance matrices and sometimes also in vectors of slope (on the covariate) coefficients. In this article the following are presented: (a) a procedure for comparing adjusted (for variations in body sizes of specimens) mean vectors of populations with unequal covariance matrices and slopes, and (b) a study to distinguish between beaked redfishes based on the analysis of a real data set by this procedure. This will also serve as a numerical example.     

Swimming Performance Assessment in Fishes

Swimming performance tests of fish have been integral to studies of muscle energetics, swimming mechanics, gas exchange, cardiac physiology, disease, pollution, hypoxia and temperature. This paper describes a flexible protocol to assess fish swimming performance using equipment in which water velocity can be controlled. The protocol involves one to several stepped increases in flow speed that are intended to cause fish to fatigue. Step speeds and their duration can be set to capture swimming abilities of different physiological and ecological relevance. Most frequently step size is set to determine critical swimming velocity (U_crit), which is intended to capture maximum sustained swimming ability. Traditionally this test has consisted of approximately ten steps each of 20 min duration. However, steps of shorter duration (e.g. 1 min) are increasingly being utilized to capture acceleration ability or burst swimming performance. Regardless of step size, swimming tests can be repeated over time to gauge individual variation and recovery ability. Endpoints related to swimming such as measures of metabolic rate, fin use, ventilation rate, and of behavior, such as the distance between schooling fish, are often included before, during and after swimming tests. Given the diversity of fish species, the number of unexplored research questions, and the importance of many species to global ecology and economic health, studies of fish swimming performance will remain popular and invaluable for the foreseeable future.