Genetic evidence for polygynandry in the black-striped pipefish syngnathus abaster: a microsatellite-based parentage analysis

Sexual selection theory predicts that, in organisms with reversed sex roles, more polyandrous species exhibit higher levels of sexual dimorphism. In the family Syngnathidae (pipefish, seahorses, and seadragons), males provide all parental care by carrying developing embryos on their ventral surfaces, and females develop secondary sex characters. Syngnathids exhibit a variety of genetic mating patterns, making them an ideal group to test predictions of sexual selection theory. Here, we describe the mating system of the black-striped pipefish Syngnathus abaster, using 4 highly variable microsatellites to analyze parentage of 102 embryos. Results revealed that 1) both sexes mate multiple times over the course of a pregnancy (polygynandrous mating system), 2) eggs are spatially segregated by maternity within each brood pouch, and 3) larger females have higher mating success (Kolmogorov–Smirnov test; P < 0.05). Together with similar studies of other syngnathid species, our results support the hypothesis that the mating system is related to the intensity of sexual dimorphism.

Induced spawning of hatchery-raised Brazilian catfish, cachara Pseudoplatystoma fasciatum (Linnaeus, 1766)

In the months of January 2001 and 2002, female cachara Pseudoplatystoma fasciatum were selected during their first and second gonadal maturation (2 years and 7 months old and 3 years and 7 months old, respectively) with an of oocyte diameter of 937.5 mum (82.5% with central nuclei and 17.5% with peripheral nuclei). Nine females in first maturation received two doses of carp pituitary extract (CPE), 0.5 mg/kg and 5.0 mg/kg; seven received two doses of human chorionic gonadotropin (hCG), 5 and 10 IU/g; five received doses of 0.5 CPE mg/kg and 5 hCG IU/g (CPE+hCG); and four received 0.9% saline (saline). Nine females from CPE and seven from hCG presented oocytes with the same diameter at the moment of oocyte release (100% with germinal vesicle breakdown and fertilization rate of 53.44 +/- 18.3 and 54.81 +/- 11.8%; larvae number of 165,330 +/- 94.1 and 158,570 +/- 20.6, respectively). The five females from CPE+hCG did not respond to the hormonal treatment. The four females from the saline group did not ovulate. In January 2002, 6 of 15 selected females that were going through the second reproductive cycle received CPE (five received hCG and four received saline), showing oocyte diameters similar to the ones in the first maturation. At stripping, CPE females had an oocyte diameter of 1062.5 mum (the hCG females had oocyte diameters ranging from 937.5 to 1125.0 mum; fertilization rates of 56.08 +/- 30.9 and 81.90 +/- 17.3%; 364,547 +/- 244 and 633,129 +/- 190, larvae, respectively). The fertilization rates and larvae number were higher in the second gonad maturation, both for CPE and hCG. (C) 2004 Elsevier B.V. All rights reserved.

Unusual striped dolphin mass mortality episode related to cetacean morbillivirus in the Spanish Mediterranean sea

BACKGROUND In the last 20 years, Cetacean Morbillivirus (CeMV) has been responsible for many die-offs in marine mammals worldwide, as clearly exemplified by the two dolphin morbillivirus (DMV) epizootics of 1990-1992 and 2006-2008, which affected Mediterranean striped dolphins (Stenella coeruleoalba). Between March and April 2011, the number of strandings on the Valencian Community coast (E Spain) increased. CASE PRESENTATION Necropsy and sample collection were performed in all stranded animals, with good state of conservation. Subsequently, histopathology, immunohistochemistry, conventional reverse transcription polymerase chain reaction (RT-PCR) and Universal Probe Library (UPL) RT-PCR assays were performed to identify Morbillivirus. Gross and microscopic findings compatible with CeMV were found in the majority of analyzed animals. Immunopositivity in the brain and UPL RT-PCR positivity in seven of the nine analyzed animals in at least two tissues confirmed CeMV systemic infection. Phylogenetic analysis, based on sequencing part of the phosphoprotein gene, showed that this isolate is a closely related dolphin morbillivirus (DMV) to that responsible for the 2006-2008 epizootics. CONCLUSION The combination of gross and histopathologic findings compatible with DMV with immunopositivity and molecular detection of DMV suggests that this DMV strain could cause this die-off event.

Age and growth, mortality and reproduction of the striped sea bream, Lithognathus mormyrus Linnaeus 1758, from the south coast of Portugal (Algarve)

The striped sea bream, Lithognathus mormyrus, used for this population dynamics study were obtained from longline catches and market sampling in the Algarve (south Portugal). The macroscopic analysis of the gonads and the gonad somatic index showed that the south Portuguese population of L. mormyrus spawns mainly between late spring and summer (June to August). The length at first maturity was similar for males and females and the value for both sexes combined was estimated to be 16.08 cm, corresponding to an age between 1 and 2 years. Fish age classes (0 to 13) were determined by reading growth rings on whole otoliths. Age determination was validated by marginal increment analysis. The estimated parameters of the von Bertalanffy growth equation were L infinity = 35.30 cm, K = 0.264 and t(0) = -0.809. Mortality rates were calculated for fish captured with longlines, and the estimated parameters were M = 0.356, Z = 0.622 and F = 0.266. From an Algarve fishery management perspective, these results suggest the need for an increase in the minimum landing size (from 15 to 17 cm), which should be beneficial for the sustainability and conservation of this species. The results also showed that fishing with longlines off the Algarve coast may allow for a sustainable use of the resource.

Spatial distribution patterns of the non-native European catfish, Silurus glanis, from multiple online sources - a case study for the River Tagus (Iberian Peninsula)

Effective management of invasive fishes depends on the availability of updated information about their distribution and spatial dispersion. Forensic analysis was performed using online and published data on the European catfish, Silurus glanis L., a recent invader in the Tagus catchment (Iberian Peninsula). Eighty records were obtained mainly from anglers’ fora and blogs, and more recently from www.youtube.com. Since the first record in 1998, S. glanis expanded its geographic range by 700 km of river network, occurring mainly in reservoirs and in high-order reaches. Human-mediated and natural dispersal events were identified, with the former occurring during the first years of invasion and involving movements of >50 km. Downstream dispersal directionality was predominant. The analysis of online data from anglers was found to provide useful information on the distribution and dispersal patterns of this non-native fish, and is potentially applicable as a preliminary, exploratory assessment tool for other non-native fishes.

Multidisciplinary approach to manage the striped venus clam (Chamelea gallina) fisheries

To responsively manage the striped venus clam (Chamelea gallina) fisheries, a multidisciplinary approach has been adopted through the investigation of new and updated biological aspects (e.g. age, growth, reproduction, size at first maturity, fecundity) and the interaction gear- target or non-target species (e.g. reburial ability, survival potential and exerted damage). The striped venus clam is an important socio-economic species in the Italian fishery context, highly regulated by national and international laws aiming at guaranteeing both social and ecological sustainability. Studies on growth and reproduction revealed that the size at first maturity is reached within the first year of life, whereas the present Minimum Conservation Reference Size of 22 mm is reached at two year of age. The annual reproductive cycle, which is driven by rises in seawater temperature and chlorophyll-a concentration, spans during the warmer months (late spring-summer) with multiple spawning events of different intensity occurring over the spawning period, and the number of potentially emitted gametes is positively related to shell size. Reburial tests conducted on undamaged specimens highlighted the ability of clams to rebury in the sediment once discarded, independently from the size. On the other hand, survival experiments in the laboratory and at sea, on both damaged and undamaged individuals, served to demonstrate that the species has a high survival rate, thus supporting the claim that discarded individuals can contribute to restock the natural populations. Moreover, the evaluation and quantification of damage induced by dredging on the discarded macro-benthic fauna living associated with C. gallina highlighted that soft-shelled or soft-bodied species are the most affected by the fishing process and subjected to a higher mortality. All these findings are of pivotal importance to rationally support the management measures to be adopted in the striped venus clam fishery.

Induced spawning of the endangered Neotropical species Steindachneridion parahybae (Siluriformes: Pimelodidae)

The "surubim do Paraíba" (Steindachneridion parahybae) is a freshwater catfish endemic to the Paraíba do Sul River basin, Brazil. This species has been seriously threatened by environmental disturbances in the last several decades. Wild Steindachneridion parahybae males and females were collected in 2003 and taken to the hatchery of a power plant of the Companhia Energética de São Paulo (CESP). Steindachneridion parahybae broodstocks were artificially induced to reproduce in December 2003 using a combination of carp pituitary extract (CPE) and human chorionic gonadotropin (hCG). Oocytes and milt were stripped; the fertilized eggs were transferred to 60-liter conical incubators and hatched larvae distributed in nine horizontal trays. Exogenous feed was started just after yolk sac absorption. A high rate of cannibalism and photophobia were observed during the larval period, resulting in a 26% survival rate from larvae to fingerlings.

Localization of ribosomal genes in three Pimelodus species (Siluriformes, Pimelodidae) of the São Francisco River: 5S genes as species markers and conservation of the 18S rDNA sites

Pimelodidae is one of the most representative of Neotropical catfish families. However, these fish are still poorly studied in terms of cytogenetics, especially regarding the application of more accurate techniques such as the chromosomal localization of ribosomal genes. In the present work, fluorescent in situ hybridization with 5S and 18S rDNA probes was employed for rDNA site mapping in Pimelodus sp., P. fur and P. maculatus from the São Francisco River in the Três Marias municipality - MG. The results from the application of the 18S probe confirmed the previous data obtained by silver nitrate staining, identifying a simple nucleolar organizing region system for these species. However, the labeling results from the 5S rDNA probe demonstrated a difference in the number and localization of these sites between the analyzed species. The obtained data allowed inferences on the possible processes involved in the karyotypic evolution of this genus.

A new species of Pimelodus La Cépède, 1803 (Siluriformes: Pimelodidae) from rio Ribeira de Iguape basin, Brazil

Pimelodus multicratifer, a new species, is described from the rio Ribeira de Iguape basin. The new species differs from the other Pimelodus species by the following features: 26 to 30 gill rakers on the first branchial arch; a combination of three to six rows of dark spots regularly or irregularly scattered on the flanks and several small dark spots irregularly scattered on the dorsal surface of head, supraoccipital process, and sometimes on the dorsal and caudal fins; striated lips; maxillary barbels reaching between posterior tip of the pelvic-fin rays and posterior tip of the middle caudal-fin rays.

A cave population of Isbrueckerichthys alipionis (Gosline, 1947) in the Upper Ribeira karst area, southeastern Brazil (Siluriformes: Loricariidae)

A cave population of the armored catfish Isbrueckerichthys alipionis is reported from the Santana Cave, in the rio Betari watershed, Upper Ribeira karst area, Iporanga, São Paulo State, southeastern Brazil. The cave population was compared to an epigean population of I. alipionis and no significant differences where found in morphology or degree of pigmentation. As the cave population is known for at least 30 years and is apparently isolated from epigean streams, it is classified as troglophilic. The discovery of this troglophilic species in the Santana Cave is an additional strong argument for the conservation of that cave.

Epigean and subterranean ichthyofauna in Cordisburgo karst area, eastern Brazil

After an ichthyofaunistic survey conducted in May 2007 on surface (epigean) water bodies of Cordisburgo karst area, State of Minas Gerais, 13 species were recorded, mostly characiforms; in addition three non-troglomorphic (normally eyed and pigmented) and one troglomorphic catfish (siluriforms) species were recorded in two caves surveyed at different occasions, totaling 17 fish species for the area. All the nominal species herein reported for Cordisburgo area have been previously reported for the Rio das Velhas basin. None of the species observed in caves were found in epigean habitats and vice-versa. The four cave species are distributed throughout subterranean stream reaches, with individuals at different size/age classes. This, associated to the lack of conspicuous morphological differences in relation to epigean congeners, indicate that Trichomycterus brasiliensis, Gymnotus cf. carapo and Pimelodella cf. vittata are troglophiles (species encompassing individuals able to live and complete their life cycle either in the surface or in the subterranean environment) in the Morena Cave; the latter forms a large population and may be at the beginning of a differentiation process due to isolation in the subterranean habitat, as indicated by a slight reduction in eye size. Topographic isolation may be the cause for the incipient, but unmistakable troglomorphism of the Rhamdiopsis population found in the Salitre Cave, allowing for its classification as troglobite (exclusively subterranean species). The Cordisburgo area is subject to significant anthropic pressure, mainly represented by deforestation for agriculture, cattle raising and timbering. Tourism is an additional important threat for cave communities, calling for urgent protection measures.

Two new species of Moenkhausia Eigenmann (Characiformes: Characidae) from Serra do Cachimbo, Pará, Northern Brazil

Two new species of Moenkhausia, one from the rio Tapajós and the other from the rio Xingu basins are described as apparently endemics of the Serra do Cachimbo. Both species, along with M. petymbuaba, share a distinct color pattern composed of large conspicuous dark blotches on the base of the body scales. Moenkhausia chlorophthalma, from rio Treze de Maio, a tributary to rio Curuá (rio Xingu basin), is distinguished by the presence of a proximal well delimited black area on the adipose fin and a green eye in life. Moenkhausia plumbea of the headwaters of tributaries of the rio Braço Norte, rio Tapajós basin is diagnosed by the presence of a dark longitudinal stripe across the eye and six branched pelvic-fin rays (vs. seven). Relationships of the new species with other Moenkhausia are discussed.

Systematics of Lamontichthys Miranda-Ribeiro (Siluriformes: Loricariidae), with the description of two new species

The taxonomic revision of the genus Lamontichthys Miranda-Ribeiro, based on the examination of 164 specimens of different river drainages throughout the Amazon basin, revealed the presence of six species of which two are new. Lamontichthys filamentosus occurs in the upper and middle portions of the rio Amazonas basin; L. llanero in the río Orinoco basin; L. maracaibero in the lago Maracaibo basin; and L. stibaros in the upper río Amazonas basin. Lamontichthys avacanoeiro, new species, occurs in the upper rio Tocantins basin; and L. parakana, new species, in the lower rio Tocantins basin. The new species represent a considerable extension in the so far known distribution of the genus. A parsimony analysis, including 87 osteological and external morphological characters from Lamontichthys and related taxa (total of 16), resulted in three most parsimonious trees with 194 steps (CI = 0.73 and RI = 0.78). The hypothesis of monophyly of Lamontichthys is corroborated and supported by six derived characters. Within Lamontichthys two monophyletic assemblages are recognized, one includes L. avacanoeiro and L. stibaros, the other includes L. maracaibero and the clade formed by L. filamentosus and L. llanero. The relationships of Lamontichthys parakana, a species that was not included in the phylogenetic analysis is discussed. The monophyly and relationships of the monotypic genus Pterosturisoma microps are also discussed.

A new species of Hemiancistrus from the rio Araguaia basin, Goiás state, Brazil (Siluriformes: Loricariidae)

Hemiancistrus cerrado is described from the tributaries of rio Araguaia, rio Tocantins basin. Hemiancistrus cerrado has external similarities with H. megalopteryx and H. punctulatus from coastal streams of southern Brazil, and can be distinguished by having a larger internarial width, 15.9-21.1% of head length (vs. 11.2-14.0% in H. megalopteryx and 11.2-13.9% in H. punctulatus) and, with little overlap, by the larger adipose-fin spine length, 9.4-13.6% of standard length (vs. 7.1-8.7% in H. megalopteryx and 7.4-10.0% in H. punctulatus). Hemiancistrus cerrado further differs from H. megalopteryx by having the pectoral-fin spine reaching maximally to the middle of the pelvic-fin spine when adpressed in adult males (vs. reaching tip). Hemiancistrus cerrado differs from other members of Hemiancistrus by color and numerous morphometric and meristic data.

Taxocenose de bagres marinhos (Siluriformes, Ariidae) da região estuarina de São Vicente, SP, Brasil

O objetivo do trabalho foi analisar a taxocenose de bagres marinhos do complexo baía-estuário de São Vicente, SP. As coletas foram mensais, no período de setembro de 2000 a agosto de 2002, em quatro regiões do estuário. Foram capturados 3.985 exemplares, pertencentes a cinco gêneros e seis espécies, totalizando 47.807 g. A espécie Cathorops spixii apresentou a maior abundância numérica com 1.569 indivíduos amostrados. No transecto I (próximo da região costeira) foi registrada a maior riqueza e no transecto IV (estuário acima) a maior abundância com 2.602 exemplares e peso de 26.236 g. Em março de 2002 registrou-se a maior abundância com 687 indivíduos e o maior peso ocorreu em fevereiro de 2002 (8.816 g). A salinidade da água de fundo, ao longo do período de estudo, variou entre 14 e 36 e a temperatura da água variou entre 19 e 30 °C. Na região amostrada foram capturados exemplares jovens e adultos, ocorrendo um predomínio de jovens, o que demonstra que esta área apresenta condições favoráveis para crescimento.