Comparison of antibodies in marine fish from clean and polluted waters of the New York Bight: relative levels against 36 bacteria.

Fish from polluted waters are subject to increased prevalence of disease. Because they respond to bacterial pathogens by producing serum antibodies, it was possible to construct a seasonal serological record in three fish species from clean and polluted waters of the New York Bight. Antibody levels were determined by testing sera for agglutinating activity against 36 strains of bacteria. Evaluation of 5,100 antibody titrations showed the following. During warm months, summer flounder (Paralichthys dentatus) from the polluted area had significantly higher antibody levels and antibody to a greater diversity of bacteria than fish from the unpolluted area. Weakfish (Cynoscion regalis) from the same polluted area shared with summer flounder raised titers to many bacteria. The greatest proportion of raised titers was against Vibrio species, although prominent titers were also seen against Aeromonas salmonicida and Haemophilus piscium, bacteria usually associated with diseases in freshwater but not marine fish. Differences between polluted and clean waters were not as evident in winter flounder (Pseudopleuronectes americanus) during cold months. This could be due, in part, to reduced antibody production at colder temperatures. The data illustrate the usefulness of the serum antibody record in identifying environmental exposure to bacteria in marine fish and indicate that the polluted New York Bight apex has increased levels and diversity of bacteria during warm months.     

Comparison of antibodies in marine fish from clean and polluted waters of the New York Bight: relative levels against 36 bacteria

Fish from polluted waters are subject to increased prevalence of disease. Because they respond to bacterial pathogens by producing serum antibodies, it was possible to construct a seasonal serological record in three fish species from clean and polluted waters of the New York Bight. Antibody levels were determined by testing sera for agglutinating activity against 36 strains of bacteria. Evaluation of 5,100 antibody titrations showed the following. During warm months, summer flounder (Paralichthys dentatus) from the polluted area had significantly higher antibody levels and antibody to a greater diversity of bacteria than fish from the unpolluted area. Weakfish (Cynoscion regalis) from the same polluted area shared with summer flounder raised titers to many bacteria. The greatest proportion of raised titers was against Vibrio species, although prominent titers were also seen against Aeromonas salmonicida and Haemophilus piscium, bacteria usually associated with diseases in freshwater but not marine fish. Differences between polluted and clean waters were not as evident in winter flounder (Pseudopleuronectes americanus) during cold months. This could be due, in part, to reduced antibody production at colder temperatures. The data illustrate the usefulness of the serum antibody record in identifying environmental exposure to bacteria in marine fish and indicate that the polluted New York Bight apex has increased levels and diversity of bacteria during warm months.     

Interrenal disease in bluegills (Lepomis macrochirus) caused by a new genus and species of myxozoan

A myxozoan species not matching with any described genus was encountered in a survey of fish parasites of freshwater fishes in New York. The parasite was observed in the kidney tubules of bluegill sunfish Lepomis macrochirus. A new genus is described to accommodate Acauda hoffmani n. gen., n. sp., which exhibits pyriform spores with longitudinal ridges and polar capsules perpendicular to the sutural plane. Spores measure 17.9-21.8 μm long and 6.9-11.0 μm wide, with spore valves each with 11-12 ridges. Two polar capsules measure 9.4-12.5 μm long by 2.9-4.0 μm wide and contain a filament coiled 10-15 times. Phylogenetic analysis places A. hoffmani n. gen., n. sp. as a sister to a Myxobilatus and a Hoferellus species. The clustering of these 3 similar genera in the larger 'freshwater' clade of myxozoans does not support their inclusion in the Sphaerosporidae but instead supports the distinct status of the Myxobilatidae Shulman 1953.     

A new species of Henneguya (Myxozoa) in the big-eyed scad (Selar crumenophthalmus) from Hawaii

We describe a new myxozoan, Henneguya akule n. sp., infecting the carangid fish Selar crumenophthalmus in Hawaii. Spores were found only in the aortic bulb, characterized by elliptical capsule with 2 tails, and pyriform polar capsules that angled toward the anterior end of the spore. Polar filaments had 3-4 coils. Parasites were present in apparently healthy fishes and caused no evident gross pathology. On microscopy, parasites evinced a mild inflammatory response in the host characterized by accumulations of eosinophilic fibrillar material around spores and a mononuclear infiltrate in the adventitia of the bulbus arteriosus. Overall prevalence was 20%, and prevalence between 2001 and 2006 ranged from 12 to 27%, but did not differ significantly between years. In contrast, prevalence of infection was highest in south-central Oahu. There was no relationship between infection status and body condition or gender of fish, and infection was absent in the smallest and largest fishes. Phylogenetically, H. akule n. sp. is most closely related to other Henneguya species infecting the heart of marine fishes based on ribosomal DNA analysis. This is the first documentation of a myxozoan parasite in marine fishes from Hawaii.     

Parasites of native and nonnative fishes of the Little Colorado River, Grand Canyon, Arizona

A 2-yr, seasonal, parasitological study of 1,435 fish, belonging to 4 species of native fishes and 7 species of nonnative fishes from the lower Little Colorado River (LCR) and tributary creeks, Grand Canyon, Arizona, yielded 17 species of parasites. These comprised 1 myxozoan (Henneguya exilis), 2 copepods (Ergasilus arthrosis and Lernaea cyprinacea), 1 acarine (Oribatida gen. sp.), 1 piscicolid leech (Myzobdella lugubris), 4 monogeneans (Gyrodactylus hoffmani, Gyrodactylus sp., Dactylogyrus extensus, and Ligictaluridus floridanus), 4 nematodes (Contracaecum sp., Eustrongylides sp., Rhabdochona sp., and Truttaedacnitis truttae), 3 cestodes (Bothriocephalus acheilognathi, Corallobothrium fimbriatum, and Megathylacoides giganteum), and 2 trematodes (Ornithodiplostomum sp. and Posthodiplostomum sp.). Rhabdochona sp. was the only adult parasite native to the LCR. Infection intensities of Ornithodiplostomum sp. and B. acheilognathi were positively correlated with length of the humpback chub Gila cypha. Adult helminths showed a high degree of host specificity, except B. acheilognathi, which was recovered from all fish species examined but was most abundant in cyprinids. Abundance of B. acheilognathi in the humpback chub was highest in the fall and lowest in the summer in both reaches of the LCR. There was no major taxonomic difference in parasite assemblages between the 2 different reaches of the river (LC1 and LC2). Parasite community diversity was very similar in humpback chub, regardless of sampling site or time. The parasite fauna of the LCR is numerically dominated by B. acheilognathi and metacercariae of Ornithodiplostomum sp. The richest and most diverse component community occurred in a nonnative species, the channel catfish Ictalurus punctatus, but infracommunity species richness was highest in a native host, humpback chub.     

Untested Assumptions: The Role of Canals in the Dispersal of Sea Lamprey, Alewife, and other Fishes in the Eastern United States

Canals provide aquatic organisms with an excellent thoroughfare to disperse, expand their range, and gain access to new drainages. The evidence used to support this contention is vast and dates to at least the early nineteenth century. In most cases however, the evidence used to defend the contention is not a direct observation of fish dispersing through a canal. Instead, the transfer is generally inferred after the new species is observed in a new watershed, one connected by a canal to the watershed in which the fish was already established. Often, these inferences are developed without considering aspects of the life history and behavior of the fishes involved, or the structure of the canal. I explore the historic transfer of sea lamprey, alewife and other fishes from one watershed to another in the inland waters of eastern North America, primarily New York. New York is an ideal area for examining this phenomenon as a canal has connected each of the five major drainages in the state during part of the previous 200 years. These twelve major canals, and the Welland Canal that connects lakes Ontario and Erie, bypassed major obstructions and created a continuous water route among drainages. Also, many of the 167 freshwater and diadromous fishes of New York exhibited distribution patterns historically limited to a watershed or set of neighboring watersheds. When several important cases are re-examined, dispersal through a canal is not the most parsimonious explanation for the presence of the species in a new drainage. To argue fish dispersal through navigation canals, researchers must consider the natural history and ecological requirements of the species, the characteristics and environmental conditions of the canal, and alternative explanations. The mere presence of a canal does not demonstrate that fish used the canal for dispersal.     

Molecular phylogenetic relationships of the deep-sea fish genus Coryphaenoides (Gadiformes: Macrouridae) based on mitochondrial DNA

In order to characterize the phylogenetic relationship and deep-sea adaptation process of the deep-sea fish genus Coryphaenoides, the nucleotide sequences of the mitochondrial (mt) 12 S rRNA and COI gene sequences for seven Coryphaenoides species were analyzed. Our molecular phylogenetic tree shows a new arrangement of seven Coryphaenoides species, which form two distinct groups, abyssal and nonabyssal species, and differs from the results of previous taxonomic studies. Using the mutation rate of mitochondrial genes, the divergence time between abyssal and nonabyssal Coryphaenoides was found to be 3.2-7.6 million years ago. Our study suggests that hydraulic pressure plays an important role in the speciation process in the marine environment.     

Genetic mixed-stock analysis of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus in a heavily exploited marine habitat indicates the need for routine genetic monitoring

Although a previous genetic mixed-stock analysis (gMSA) conducted in the early 1990s showed that marine-captured New York Bight Atlantic sturgeon Acipenser oxyrinchus oxyrinchus almost exclusively originated from the Hudson River, fish from southern U.S. rivers were well represented within this contemporary sample (n = 364 fish), at least during the autumn. Widely distributed spawning stocks are therefore exposed to heavy fishing activity and habitat degradation in this relatively small area, illustrating the need for spatial management across multiple management jurisdictions and routine gMSA to account for temporal change.     

Some new observations on the cytopathology of fin erosion disease in winter flounder Pseudopleuronectes americanus

A light and electron microscopic study was conducted on dorsal fin tissues adjacent to acute fin erosion lesions in winter flounder from 2 polluted sites (New York Bight region and New Haven Harbor) on the northeast Atlantic Coast. The objective of this work was to evaluate these minimally affected, lesion-associated tissues which may precede the acute or severe stages of the disease. The following 4 types of pathological conditions were found in the epidermis of diseased fish from the 2 polluted sites: (1) epithelial cell hyperplasia; (2) mucous cell hyperplasia and hypertrophy; (3) spongiosis; and (4) focal necrosis. The latter 2 types of lesions have not been previously reported for fin erosion in this species. Changes in the dermis associated with these lesions included fibrosis, abnormal distribution of melanocytes, hyperemia and sclerosis of blood vessels, and hemorrhage. The possibility that hypoxia may play a role in the observed pathology is considered.     

Morphological,ultrastructural, and molecular analysis of a new species of Myxobolus (Cnidaria,Myxosporea) parasitizing Apareiodon piracicabae (Characiformes,Parodontidae) from Brazil

About forty-two species of Myxobolus have been previously described to parasitize characiform fishes in South America. Here, we described a new myxozoan species, Myxobolus parodontidis n. sp., in the gills of Apareiodon piracicabae (Characiformes, Parodontidae) from the streams of the Middle Paranapanema River basin, Brazil. The proposed new species is supported by a combination of morphological, ultrastructural, and molecular characterization (small subunit ribosomal DNA). Thirteen specimens of A. piracicabae were analyzed and 30.8% was infected by Myxobolus parodontidis n. sp. The myxospores was classified as intralamellar asymmetric type. A few aberrant myxospores with three polar capsules were observed: the spore length and width were the same of normal myxospores, but the polar capsules had smaller sizes. Ultrastructural analysis showed that the plasmodial membrane of Myxobolus parodontidis n. sp. was in direct contact with the host tissue and a connective capsule surrounding the plasmodium was not observed. The phylogenetic analysis showed that the main influence in the clustering of species of myxobolids seems to be related to the phylogenetic relationships established among fish hosts, mainly at the level of family and order. This is the first record of a myxozoan species parasitizing parodontid fish, contributing to the knowledge of the biodiversity of myxozoans from Brazil.     

Notes on age determination,size and age structure,longevity and growth of co-occurring macrourid fishes

Nineteen species of the deep-water fish family Macrouridae inhabit the Mid-Atlantic Ridge (MAR) of the North Atlantic. Size and age structure, longevity and length at age were explored for seven of the more abundant species: Coryphaenoides armatus, Coryphaenoides brevibarbis, Coryphaenoides carapinus, Coryphaenoides guentheri, Coryphaenoides mediterraneus, Coryphaenoides rupestris and Macrourus berglax. The otoliths from these species had growth increments resembling those accepted as annuli in other deep-water species for which validation experiments have been conducted. Based on the counts of these growth increments, age estimates were derived as the basis for studies of age structure, growth and longevity. All the species appeared to have relatively low growth rates, but the interspecific variation in longevity illustrates that there is a considerable variation within the family and among species inhabiting the same deep-sea environment. Most of the species likely complete full life cycles on the MAR, but it is probable that both the youngest and the largest-oldest individuals of some of the species were not sampled adequately.     

Some differences in the parasitic fauna of three samples of plaice (Pleuronectesplatessa L.) from the southern North Sea

Plaice ( Pleuronectesplatessa L.) from three spawning areas in the southern North Sea were examined for six species of metazoan parasite. Differences of both incidence and level of infestation with particular parasite species were found in fish from the three areas. Neither the incidence nor the level of infestation was associated with the length of fish in the samples except in the case of the larger male fish from Flamborough, which tended to contain more larval nematodes (Anisakidae). All fish contained the intestinal nematode Cucullanus heterochrous , although fewer were found in fish from Flamborough. Southern Bight fish were more likely to contain Capillaria wickinsi than were fish from Flamborough or the German Bight. Flamborough fish were more likely to contain Anisakidae larvae than were fish from the other two areas. Fish from the three areas were similarly infested with Zoogonoides viviparus. Male fish from Flamborough were less likely to be infested with Lepeophtheirus pectoralis than male fish from the German Bight.     

Comparative study of some haematological and biochemical blood parameters in fishes from the Skagerrak

Marine fishes caught in the Skagerrak, 27 different species representing various groups of fishes (Cyclostomi, Holocephali, Elasmobranchii and Teleostei), were examined for the following haematological and biochemical blood parameters: haematocrit, haemoglobin, mean corpuscle haemoglobin concentration, total plasma protein, blood glucose and blood lactate. Interspecies variations as well as variations within some species were observed. The haemoglobin values for all species showed a positive correlation to the corresponding haematocrit values. Relatively low values for haematocrit and haemoglobin were found in cyclostomes, holocephaleans and elasmobranchii compared to the majority of teleosts. Within the teleost group, the haematocrit and haemoglobin levels were positively correlated with the activity of the fish species. The cyclostome Myxine glutimsa L. had a total plasma protein content in the same range as most teleosts, whereas holocephaleans, elasmobranchii and the deep-water teleost Coryphaenoides rupestris Gunnerus showed comparatively low values. Among teleosts some relationship seemed to exist between the total plasma protein level and the activity of the fish species. In addition, a correlation between plasma protein content and levels of blood lipids were noted. Values for blood glucose and blood lactate were found to be lower in cyclostomes, holocephaleans and elasmobranchii than in most teleosts. Higher blood glucose levels were observed in the more active teleost species.     

Structure-based analysis of high pressure adaptation of alpha-actin

Deep-sea fishes occur to depths of several thousand meters, and at these abyssal depths encounter pressures that shallower living fishes cannot tolerate. Tolerance of abyssal pressures by deep-sea fish is likely to depend in part on adaptive modifications of proteins. However, the types of structural modifications to proteins that allow function at high pressure have not been discovered. To elucidate the mechanisms of protein adaptation to high pressure, we cloned the alpha-skeletal actin cDNAs from two abyssal Coryphaenoides species, C. armatus and C. yaquinae, and identified three amino acid substitutions, V54A or L67P, Q137K, and A155S, that distinguish these abyssal actins from orthologs of alpha-actin from non-abyssal Coryphaenoides. These substitutions, Q137K and A155S, prevent the dissociation reactions of ATP and Ca2+ from being influenced by high pressure. In particular, the lysine residue at position 137 results in a much smaller apparent volume change in the Ca2+ dissociation reaction. The V54A or L67P substitution reduces the volume change associated with actin polymerization and has a role in maintaining the DNase I activity of actin at high pressure. Together, these results indicate that a few amino acid substitutions in key functional positions can adaptively alter the pressure sensitivity of a protein.     

Interrelationships of the subgenera of Coryphaenoides (Teleostei: Gadiformes: Macrouridae): synthesis of allozyme,peptide mapping,and DNA sequence data

DNA sequences of the 12s rRNA mitochondrial gene from 12 species key to the question of the monophyly of the deep-sea fish genus Coryphaenoides (Macrouridae) were analyzed phylogenetically using maximum parsimony and maximum likelihood. The results were compared with those of three previous studies in which allozyme, peptide mapping, and DNA sequence data were similarly analyzed. The allozyme and DNA sequence data suggested that the largest subgenus (Coryphaenoides), which contained most of the species inhabiting continental slopes between approximately 600 and 2000m depth, is monophyletic. Two of the three subgenera containing the species inhabiting abyssal ocean basins below approximately 2000m together formed a sister group to subgenus Coryphaenoides. The macrourids of the abyssal basins and those of the continental slopes thus appear to have experienced separate radiations from a common ancestor.     

Diseases in North Sea fishes

Prior to the studies reviewed here, only lymphocystis and skeletal deformities of a variety of fish species and certain diseases of eel were known to occur in the German Bight (North Sea). From 1977 until now, 9 externally visible lesions on North Sea fishes were observed; in addition to those mentioned before, they comprise: fin rot, ulcerations, epidermal papilloma, hyperplasia, pseudobranchial tumour, eye diseases and gill swellings. With the exception of information on changes in frequencies of vertebral deformities of herring from the 1950's to the 1970's, there are no long-term data characterizing changes in frequencies of the diseases under study. For pseudobranchial tumours of cod and epidermal papilloma of dab, information is provided on occurrence and abundance. The distribution pattern of cod afflicted with pseudobranchial tumours is strongly influenced by the migratory behaviour of the fish. Epidermal papillomas of dab were more frequently found at stations within the inner German Bight than in neighbouring areas. The Bight is used for dumping of wastes from titaniumdioxide production. Further disease hot spots are areas off the Humber estuary and the British coast. Analysis of chromium in dab from the German Bight revealed elevated concentrations in epidermal tissues of specimens from the dumping area compared with that found in dab from neighbouring localities. Particulate iron was demonstrated to occur in mucous cells of dab from the dumping area. From increased levels of heavy metals with cancerogenic potential in sensitive target tissues and from increased prevalences of diseased fish in the dumping area it is concluded that these phenomena are possibly causally linked. In the vicinity of the Humber estuary high disease rates were encountered and areas with high prevalences of dab afflicted with epidermal papilloma extended over regions shown to be transport routes for persistent pollutants such as radioactive materials. It is therefore suggested that the long-range distribution of fish diseases in the southern North Sea might reflect the long-range transport of persistent pollutants.     

Myxidium leei (Myxozoa) infections in aquarium-reared Mediterranean fish species.

An episode of parasitic enteritis causing trickling mortalities at an exhibition aquarium reproducing Mediterranean ecosystems was found to be caused by the myxozoan parasite Myxidium leei Diamant, Lom & Dykova 1994. The myxozoan was recorded in 25 different fish species belonging to 16 Genera, 10 Families and 4 Orders. It was mainly detected in the intestine of affected fish, and was responsible for severe chronic enteritis. The parasite was probably introduced into the facilities with infected wild fish, and transmitted directly from fish to fish by cohabitation, transfer of infected material and necrophagia. Fish belonging to the Families Labridae and Blenniidae appeared as most susceptible, and the incidence of infections in members of the Sparidae was low. This study significantly widens the host spectrum for this virulent parasite and now includes many ubiquitous coastal Mediterranean species. Wild fish may have a significant role in the transmission of myxidiosis of cultured sparid fish.     

Description of a new species of myxobolid parasite,Henneguya pindaibensis n. sp. (Cnidaria: Myxosporea), infecting the gills of Boulengerella cuvieri (Spix and Agassiz, 1829) from Brazil

Myxozoans are microscopic cnidarians that mainly parasitize fishes. The present study aimed to describe a new myxozoan parasite from the gills of Boulengerella cuvieri (Spix and Agassiz, 1829) by morphological and molecular analysis. The fish was collected in 2019 at the Pindaíba River, municipality of Cocalinho, Mato Grosso State, Brazil. Whitish and circular plasmodia were found in the primary gill filaments, occupying an intralamellar position, with an average of 0.5 mm in diameter. Henneguya Thélohan, 1892 myxospores found inside the plasmodia were elongated and ellipsoidal, consisting of two long and elliptical shell valves with two long, tapering caudal appendages. Morphometric measurements revealed a total spore length of 36.1 ± 2.0 μm; spore body length of 12.8 ± 0.5 μm; spore width of 4.9 ± 0.3 μm; tail length of 23.3 ± 1.6 μm; capsule length of 7.2 ± 0.4 μm; capsule width of 1.5 ± 0.2 μm; and 10 coils in the polar filament. Phylogenetic analysis showed that the isolates from this study were grouped into the main-clade of freshwater fishes, within a group of species parasitizing fishes from Brazil. Intergenotypic difference ranged from 23%–25.9% compared with other Brazilian myxozoan isolates. Using molecular and morphological characterization, this parasite was identified as a new species of the genus Henneguya.     

A seasonal analysis of the nutritional condition of deep-sea macrourid fishes in the north-east Pacific

Of three common macrourids Coryphaenoides armatus and Coryphaenoides yaquinae were collected from 1995 to 1998 at an abyssal station, c . 220 km west of Point Conception, California in the north-east Pacific (4100 m depth). Coryphaenoides acrolepis was collected from 1997 to 1998 in the San Diego Trough (1200 m depth). Energy storage in all three species was primarily in the liver, which was up to 56% lipid (wet mass) and up to 96% triglyceride. No seasonal variation in nutritional condition was found for C. armatus or C. yaquinae . There was, however, a significant increase in muscle water content and liver lipid content and a significant decline in muscle lactate dehydrogenase activity for C. armatus between 1996 and 1998. Potential mechanisms for these interannual shifts are proposed. No seasonal variation in parameters was found for C. acrolepis but a small seasonal periodicity in feeding activity may have existed. The seasonal deposition of phytodetritus in the deep sea is of little or no consequence to these fishes.     

Demersal fish assemblages associated with hard bottom habitat in the South Atlantic Bight of the U.S.A.

Synopsis Demersal fish communities associated with hard bottom habitats in the South Atlantic Bight were investigated in three depth zones (inner, middle and outer shelf) between 30° and 33°N latitudes. Fishes were sampled with trawls and baited fishing gear, and were observed by remotely operated underwater television. Most demersal hard bottom fishes demonstrated seasonal differences in abundance in each depth zone, especially at the inner and outer shelf stations. Diversity values from trawl catches were higher in winter than summer at inner and outer shelf stations, but lower in winter at middle shelf stations. Species richness was higher in summer than in winter at most stations, but H' diversity patterns were more influenced by community evenness. Diversity values were higher than those reported for similar depths in the Middle Atlantic Bight. Mean biomass of demersal teleosts for all stations combined was slightly greater in winter than in summer. There was no significant difference in biomass between stations in summer, however, middle shelf stations had significantly greater biomass than inner or outer shelf stations in winter. Biomass estimates from the hard bottom areas studied were considerably higher than those reported in the literature for sand bottom areas in the South Atlantic Bight, but less than those reported for tropical reefs. Cluster analysis revealed differences in community composition between day and night trawl tows at all stations, and greater seasonal differences in species composition at inner and outer shelf stations than at middle shelf depths. Underwater television provided useful complementary data to trawl catches, documented the presence of large fishes which avoided the trawl, and provided information on the community composition at high relief stations which could not be trawled.