Skeletal deformities and meristic trait variations are common in the intertidal fish Bathygobius cocosensis (Perciformes-Gobiidae).

Extreme environmental conditions, such as temperature, can lead to meristic trait variation and skeletal deformities, which may have major impacts on individual fitness. As intertidal ecosystems experience rapid temperature and physicochemical fluctuations, intertidal fish living and reproducing in these environmental conditions may have phenotypes influenced by such variable environments. The impact of intertidal variability on fish development, however, has not been previously investigated. Skeletal deformities and meristic traits were assessed for Bathygobius cocosensis, a common intertidal fish living across the Indo-Pacific region, using a clearing and staining method on 72 individuals. Over 87% of individuals presented meristic variation and over 70% exhibited at least one type of skeletal deformity, mostly recorded in the caudal fin area. The unexpected prevalence of skeletal deformities among this intertidal fish population suggests that such deformities may be suitable markers to evaluate an individual's stress exposure during development and the subsequent fitness effects.

An evaluation of a double-tailed deformity in a coral-reef surgeonfish Acanthurus nigrofuscus (Acanthuridae) using micro-computed tomography.

X-ray micro-computed tomography scans were used to examine the caudal-fin structure of an unusual double-tailed deformity in an adult brown surgeonfish Acanthurus nigrofuscus from the Great Barrier Reef. In both this case and in a similar double-tailed deformity in a juvenile Tomini surgeonfish Ctenochaetus tominiensis from the Philippines, the caudal fin was duplicated along the dorsoventral axis. Detailed examination of the A. nigrofuscus specimen revealed that the deformity was associated with duplication and reflection of the hypural plates and the posterior vertebrae, yet the fish survived to adulthood, indicating that the effects of duplication on survival may be limited.

First report of a cystic malformation on the upper jaw of hatchery-reared allis shad Alosa alosa.

The anadromous allis shad Alosa alosa has suffered dramatic population declines throughout Europe and is currently considered as endangered throughout its entire distribution range. In order to reestablish allis shad in the River Rhine, which formerly housed one of the largest and most important populations, an EU-LIFE Project 'The re-introduction of allis shad in the Rhine system' was started in 2007. In course of the LIFE+ Projects, allis shad larvae bred from genitor fish of the Gironde-Garonne-Dordogne population in France were reared in a pilot ex situ stock plant pilot facility in Aßlar, Germany. At an age of 1-2 months, about 100% of these fish developed approximately 0.5- to 0.8-cm large, fluid-filled, transparent cysts in conjunction with the upper jaw. The performed microbiological, virological, parasitological and histological examinations did not detect any infectious agents. Possible causative agents are discussed with regard to environmental factors and the nutrition of larvae. In conclusion, the observed malformations are considered a sign for a severe health problem and therefore a risk for the successful breeding of allis shad in aquaculture.

Alternative splicing of Wilms tumor suppressor 1 (Wt1) exon 4 results in protein isoforms with different functions.

The Wilms tumor suppressor gene Wt1 encodes a zinc finger transcription factor that is essential for development of multiple organs including kidneys, gonads, spleen and heart. In mammals Wt1 comprises 10 exons with two characteristic splicing events: inclusion or skipping of exon 5 and alternative usage of two splice donor sites between exons 9 and 10. Most fish including zebrafish and medaka possess two wt1 paralogs, wt1a and wt1b, both lacking exon 5. Here we have characterized wt1 in guppy, platyfish and the short-lived African killifish Nothobranchius furzeri. All fish except zebrafish show alternative splicing of exon 4 of wt1a but not of wt1b with the wt1a(-exon 4) isoform being the predominant splice variant. With regard to function, Wt1a(+exon 4) showed less dimerization but stimulated transcription more effectively than the Wt1a(-exon 4) isoform. A specific knockdown of wt1a exon 4 in zebrafish was associated with anomalies in kidney development demonstrating a physiological function for Wt1a exon 4. Interestingly, alternative splicing of exon 4 seems to be an early evolutionary event as it is observed in the single wt1 gene of the sturgeon, a species that has not gone through teleost-specific genome duplication.

Diseases of captive yellow seahorse Hippocampus kuda Bleeker, pot-bellied seahorse Hippocampus abdominalis Lesson and weedy seadragon Phyllopteryx taeniolatus (Lacépède).

Seahorses, pipefish and seadragons are fish of the Family Syngnathidae. From 1998 to 2010, 172 syngnathid cases from the Toronto Zoo were submitted for post-mortem diagnostics and retrospectively examined. Among the submitted species were yellow seahorses Hippocampus kuda Bleeker (n=133), pot-bellied seahorses Hippocampus abdominalis Lesson (n=35) and weedy seadragons Phyllopteryx taeniolatus (Lacépède; n=4). The three most common causes of morbidity and mortality in this population were bacterial dermatitis, bilaterally symmetrical myopathy and mycobacteriosis, accounting for 24%, 17% and 15% of cases, respectively. Inflammatory processes were the most common diagnoses, present in 117 cases. Seven neoplasms were diagnosed, environmental aetiologies were identified in 46 cases, and two congenital defects were identified.

Teratogenic effects and monetary cost of selenium poisoning of fish in Lake Sutton, North Carolina.

Selenium pollution from coal ash wastewater was investigated in Lake Sutton, NC. This lake has been continuously used as a cooling pond for a coal-fired power plant since 1972. Historic and recent levels of contamination in fish tissues (14-105µg Se/g dry weight in liver, 24-127 in eggs, 4-23 in muscle, 7-38 in whole-body) exceeded toxic thresholds and teratogenic effects were observed in fish collected in 2013. A high proportion (28.9 percent) of juvenile Lepomis spp. exhibited spinal and craniofacial malformations that were consistent with selenium poisoning. Teratogenic Deformity Index values indicated population-level impacts on the fishery. The partially monetized cost of resultant fishery losses was calculated at over $US 8.6 million annually, and over $US 217 million for the entire period of damage, which dates back to 1987 when chemical and biological monitoring began.

Malformations of the endangered Chinese sturgeon, Acipenser sinensis, and its causal agent.

The anadromous Chinese sturgeon (Acipenser sinensis) is endangered and listed among the first class of protected animals in China. The possible causes for the decline of this species are the effects of synthetic chemicals, and loss of critical habitat. Chinese sturgeon in the Yangtze River have accumulated triphenyltin (TPT) to 31-128 ng/g wet weigh (ww) in liver, which is greater than the concentrations of tributyltin (<1.0 ng/g ww). Maternal transfer of TPT has resulted in concentrations of 25.5 +/- 13.0 ng/g ww in eggs of wild Chinese sturgeon, which poses a significant risk to the larvae naturally fertilized or hatched in the Yangtze River. The incidence of deformities in fry was 7.5%, with 1.2% of individuals exhibiting ocular abnormal development, and 6.3% exhibited skeletal/morphological deformations. The incidences of both ocular and skeletal/morphological deformations were directly proportional to the TPT concentration in the eggs of both the Chinese sturgeon and the Siberian sturgeon (Acipenser baerii) in controlled laboratory studies. The rates of deformities in the controlled studies were consistent with the rates caused at the similar concentrations in eggs collected from the field. Thus, TPT is the causal agent to induce the malformation of larvae of Chinese sturgeon. The incidence of deformed larvae of Chinese sturgeon is an indicator of overall population-level effects of TPT on Chinese sturgeon, because TPT at environmentally relevant concentrations can result in significantly decrease both quality and quantity of eggs and spawning frequency of fish.

Injuries and deformities in fish: their potential impacts upon aquacultural production and welfare.

Fish can be the recipients of numerous injuries that are potentially deleterious to aquacultural production performance and welfare. This review will employ a systematic approach that classifies injuries in relation to specific anatomical areas of the fish and will evaluate the effects of injury upon production and welfare. The selected areas include the (1) mouth, (2) eye, (3) epidermis and (4) fins. These areas cover a large number of external anatomical features that can be injured during aquacultural procedures and husbandry practices. In particular, these injuries can be diagnosed on live fish, in a farm environment. For each anatomical feature, this review addresses (a) its structure and function and (b) defines key injuries that can affect the fish from a production and a welfare perspective. Particular attention is then given to (c) defining known and potential aquacultural risk factors before (d) identifying and outlining potential short- and long-term farming practices and mitigation strategies to reduce the incidence and prevalence of these injuries. The review then concludes with an analysis of potential synergies between risk factors the type of injury, in addition to identifying potential synergies in mitigation strategies. The paper covers both aquaculture and capture-based aquaculture.

Overview of developmental heart defects by dioxins, PCBs, and pesticides.

The developing cardiovascular system is a sensitive target of many environmental pollutants, including dioxins, dioxin-like polychlorinated biphenyls (PCBs), and some pesticides such as methyl parathion. Laboratory research has utilized a variety of vertebrate models to elucidate potential mechanisms that mediate this cardioteratogenicity and to establish the sensitivity of different species for predicting potential risk to environmental and human health. Studies of dioxin and dioxin-like PCBs have illustrated that piscine, avian, and mammalian embryos exhibit cardiovascular structural changes and functional deficits, although the specific characteristics vary among the individual models. Piscine models typically exhibit reduced blood flow, altered heart looping, and reduced heart size and contraction rate. The chick embryo exhibits extensive cardiac dilation, thinner ventricle walls, and reduced responsiveness to chronotropic stimuli, while the murine embryo exhibits reduced heart size. It is notable that in all models the dioxin-associated cardioteratogenicity is associated with increases in cardiovascular apoptosis and decreases in cardiocyte proliferation. While the cardiotertogenicity in piscine and avian species is associated with overt morbidity and mortality, that is not the case for the murine embryo. However, murine offspring exposed during development to dioxin exhibit cardiac hypertrophy and an increased sensitivity to a second cardiovascular insult in adulthood. Thus, although the mammalian embryo is less sensitive to cardiovascular defects by dioxin and dioxin-like compounds, developmental exposure increases the risk of cardiovascular disease later in life. The impact of developmental exposure to dioxin-like chemicals on human cardiovascular disease susceptibility is not known. However, recent animal research has confirmed human epidemiology studies that dioxin exposure in adulthood is associated with hypertension and cardiovascular disease.

The First Record of Incidences of Ankylosis in Seven Triplefin Fishes (Pisces: Tripterygiidae) from New Zealand.

Different cases of vertebral ankylosis were examined in seven tripterygiid species obtained from waters around New Zealand. The skeletal deformities observed are located in the caudal region of the vertebral column. Those occurred in Forsterygion nigripenne, Matanui bathytaton and in one specimen of Ruanoho whero were severe cases. The mechanism of the formation of vertebral ankylosis and the causes behind such anomaly were discussed. Further studies are needed to relate specific pollutants with the observed types of deformities. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:39-45, 2018. © 2017 Wiley Periodicals, Inc.

Dorsoventral transposition of the heart chambers in sturgeon Acipenser naccarii alevins.

This is the first description of a dorsoventral transposition of the heart chambers in sturgeons Acipenser naccarii. The affected individuals were 2 farmed alevins aged 9 and 10 d posthatching, respectively. One was examined by light microscopy and the other by scanning electron microscopy. In both cases, the atrium and sinus venosus occupied a left ventrolateral position, the ventricle, conus arteriosus and bulbus arteriosus were located dorsally, and the transverse septum was incomplete. The anomalous heart examined by light microscopy did not differ histologically from normal hearts of similar developmental stages. The abnormal dorsoventral arrangement of the heart chambers was presumably due to a distortion of the morphogenetic movements that bring the ventricle to the ventral and the atrium to the dorsal position. The present findings, together with genetic data reported in the literature, suggest that the defective cardiac phenotype detected in the present specimens might result from a mutation affecting the sturgeon ortholog of the zebrafish overlooped (olp) gene.

Chemical contamination in aquatic ecosystems.

The 21st Century's Center of Excellence (COE) Program "Coastal Marine Environmental Research" in Ehime University, funded by the Ministry of Education, Culture, Sports, Science and Technology, Government of Japan, started its activities in October 2002. One of the core projects of the COE Program in Ehime University is "studies on environmental behavior of hazardous chemicals and their toxic effects on wildlife". This core project deals with studies of the local and global distribution of environmental contaminants in aquatic ecosystems, retrospective analysis of such chemicals, their toxicokinetics in humans and wildlife, molecular mechanisms to determine species-specific reactions, and sensitivity of chemically induced effects, and with the development of methodology for risk assessment for the conservation of ecological and species diversity. This presentation describes our recent achievements of this project, including research on contamination by arsenic and organohalogen pollutants in the Mekong River basin and molecular mechanisms of morphologic deformities in dioxin-exposed red seabream (Pagrus major) embryos. We established the Environmental Specimen Bank (es-BANK) in Ehime University in 2004, archiving approximately 100000 cryogenic samples containing tissues of wildlife and humans that have been collected for the past 40 years. The CMES homepage offers details of samples through online database retrieval. The es-BANK facility was in operation by the end of 2005.

Terminology of gonadal anomalies in fish and amphibians resulting from chemical exposures.

Given the recent increase in the number of studies describing the ability of chemicals to exert endocrine-disrupting effects, not only in fish but in a variety of other oviparous groups such as amphibians and reptiles, there is an urgent need to harmonize the terminology currently used in describing pathological changes of the gonads. In addition to difficulties in comparing results from different studies, there is also the risk of miscommunication by using terms that imply a certain clinical relevance which may not be true for the species examined. Especially in the case of the recent and controversial issue about potential effects of the triazine herbicide atrazine on amphibians, clinical terminology has been utilized beyond its true meaning by using terms such as "chemical castration" to describe occurrence of TOs or ovarian tissue in the testis of male frogs exposed to environmental chemicals (Hayes 2004). In clinical terminology, castration is defined as the removal of the gonads or their destruction by an external influence, resulting in a nonfertile organism. However, Hayes (2004) did not investigate any possible effects on the fertility of the test animals and thus did not know if these animals were truly castrated. Similarly, terms such as intersex, hermaphrodite, and sex reversal have been used in ways that appear inappropriate with regard to their clinical meaning in a series of different studies with fish or frogs (see previous sections for a detailed discussion). To ensure the appropriate use of certain terminology in a field as controversial and complex as the study of endocrine disruption, we have attempted, in this chapter, to harmonize the terminology used to describe changes in gonadal development of vertebrates such as fish and amphibians, especially frogs (see Table 3). Where appropriate, the terminology suggested was adopted directly from the clinical terminology. However, as outlined here there are substantial differences between the developmental biology of oviparous vertebrates and mammals, and especially humans, that necessitate modification of the definitions of some of the clinical terms. Where appropriate, therefore, the terminology proposed in this manuscript was redefined based on the biological meanings of the terms used in clinical diagnosis. Considering the large increase in research in the area of reproductive endocrine disruption over the past decades, the authors see an increasing need for a harmonization of terms to be used to describe effects observed in the investigated species. Agreement on a common terminology will allow scientists to better communicate and compare their work, and will enable risk assessors to conduct large-scale evaluations of environmental endocrine disruption by fitting the information from individual studies into a synthesis of normal and abnormal conditions of gonadal tissues.

The presence of hyperostosis in Atlantic moonfish, Selene setapinnis (Mitchill, 1815) in the Brazilian Coast - case report / [A presença de hiperostoses no peixe-galo-sem-penacho, Selene setapinnis (Mitchill, 1815) na costa brasileira - relato de caso]

The occurrence of hyperostotic bones is common in marine fish, especially in the Carangidae family, despite few records of this condition in fishes from Brazilian waters. The present study describes the occurrence of hyperostosis in Atlantic moonfish (Selene setapinnis) in, Rio de Janeiro State, Brazil. Radiographs of the fish specimens were taken and all of them presented hyperostosis in at least three different regions: cleithrum, pterygiophores and pleural ribs. The observed pattern is different from previously described for other species of the same genus. It is the first record for the species and a valuable contribution to the study of bone diseases in fishes from the Brazilian coast.(AU)

A ocorrência de ossos hipertostóticos é comum em peixes marinhos, especialmente na família Carangidae, apesar de poucos relatos dessa condição em peixes de águas brasileiras. O presente estudo descreve a ocorrência de hiperostose no peixe-galo-sem-penacho (Selene setapinnis) no estado do Rio de Janeiro, Brasil. Radiografias dos espécimes de peixes foram feitas e todos os exemplares apresentaram hiperostoses em pelo menos três regiões diferentes: cleithrum, pterigióforos e costelas pleurais. O padrão observado é diferente do descrito previamente para outras espécies do mesmo gênero. Este é o primeiro relato para a espécie e é uma contribuição valiosa para o estudo de doenças ósseas em peixes da costa brasileira.(AU)

Rule of accumulation of enrofloxacin in Acipenser baerii and drug-induced damage to the tissues.

Enrofloxacin (ENX) has been widely used in the prevention and control of bacterial diseases in sturgeon aquaculture due to its characteristics of wide antibacterial spectrum, strong antibacterial activity, less toxicity and fewer side effects, rapid action, extensive in vivo distribution, and little cross-resistance with other antibiotics. However, the spinal abnormality was found in Acipenser baerii soon after ENX administration, which resulted an "S"-shaped curvature of the spine and retarded fish growth. It was still not clear whether ENX could cause spinal abnormality in sturgeons by now. The aim of this work was to determine the accumulation rule and toxicity of ENX to A. baerii when used at a high dose and/or unusually long durations. Here, ENX was orally given to A. baerii for 3-5 d continuously at the dosage of 0, 20, 40, and 80 mg/kg once daily, respectively. The accumulation of ENX in blood, liver, kidney, and cartilage was detected after withdrawal, and the tissues were made into sections for morphological examination. The results showed that the levels of ENX increased in the four tissues with the increase of dose and duration, and the ENX level in serum was far lower than that in other tissues. At 240 h, ENX levels in the four tissues decreased significantly. The histology indicated that the liver, kidney, and cartilage began to show structural damages at 5 d after withdrawal of 40 mg/kg ENX. The damage was aggravated at 3-5 d after withdrawal of 80 mg/kg ENX. At 240 h, the damaged tissues showed signs of recovery. These results suggested that ENX should be no more than 40 mg/kg and that exposure time should not be greater than 5 d to prevent liver, kidney, and cartilage damage. More attention should be paid to the impact of ENX on the occurrence and development of chondrocytes in juvenile A. baerii and the potential damage to the cartilage.

Deformation of the notochord by pressure from the swim bladder may cause malformation of the vertebral column in cultured Atlantic cod Gadus morhua larvae: a case study.

This study describes a malformation that frequently occurs in Atlantic cod Gadus morhua in intensive culture systems. The malformation is characterised by a slight upward tilt of the head and an indented dorsal body contour at the transition between the head and the trunk, and is first evident to the fish farmer when the cod reach the juvenile stage. These abnormalities are associated with malformations of the neurocranium, the cranial region of the vertebral column and the cranial part of the epaxial lateral muscles. The pathogenesis involves deformation of the notochord, which can be observed in larvae about 7 d post-hatch (dph) and onwards. The deformation consists of an increase in dorsal curvature of the notochord in the region above the swim bladder. In the same region, the notochord has an abnormal cross-sectional outline, characterised by a groove-shaped, longitudinal impression along the ventral surface of the sheath. In most cases, the swim bladder fills the impression, and in severely affected larvae it forms a hernia-like lesion in the notochord. The deformation of the notochord seems to be conveyed to the vertebral body anlagen (chordacentra), which in teleosts are formed by mineralisation within the notochordal sheath. The vertebral bodies adopt an abnormal wedge shape, with a ventral concavity, and the neural arches are most often S-shaped. A continuous range of degrees of the malformation can be observed. All these pathomorphological characteristics are compatible with the notion that the notochord has been subjected to an upward mechanical force, probably generated by a persistent increase in pressure between the swim bladder and the notochord during the period of development of the vertebral anlagen. Our results thus indicate that the critical time window with regard to development of the malformation is from 18 to 36 dph, when the initial formation of the vertebrae takes place. Chronic overinflation of the swim bladder or pathological dilatation of the digestive tract may cause the lesions, and aetiology may be related to factors that influence the function of these organs.