Observations of coastal aggregations of the broadnose sevengill shark (Notorynchus cepedianus) in Chilean waters

The presence of four sharks was documented in coastal waters of Antofagasta (Chile) using an unmanned aerial video camera. Fishers took advantage of this aggregation to catch and sold three adult broadnose sevengill sharks Notorynchus cepedianus. Species identity was determined by using the cox1 gene. One additional video was later recorded 3000 km south of Antofagasta, and shows a large female interacting with a salmon farming facility. Shallow water records of N. cepedianus were previously undocumented in Chilean waters, yet historically have provided an opportunistic event to fishers in Chile.     

Fine-scale movements of the Broadnose Sevengill shark and its main prey, the Gummy shark

Information on the fine-scale movement of predators and their prey is important to interpret foraging behaviours and activity patterns. An understanding of these behaviours will help determine predator-prey relationships and their effects on community dynamics. For instance understanding a predator's movement behaviour may alter pre determined expectations of prey behaviour, as almost any aspect of the prey's decisions from foraging to mating can be influenced by the risk of predation. Acoustic telemetry was used to study the fine-scale movement patterns of the Broadnose Sevengill shark Notorynchus cepedianus and its main prey, the Gummy shark Mustelus antarcticus, in a coastal bay of southeast Tasmania. Notorynchus cepedianus displayed distinct diel differences in activity patterns. During the day they stayed close to the substrate (sea floor) and were frequently inactive. At night, however, their swimming behaviour continually oscillated through the water column from the substrate to near surface. In contrast, M. antarcticus remained close to the substrate for the entire diel cycle, and showed similar movement patterns for day and night. For both species, the possibility that movement is related to foraging behaviour is discussed. For M. antarcticus, movement may possibly be linked to a diet of predominantly slow benthic prey. On several occasions, N. cepedianus carried out a sequence of burst speed events (increased rates of movement) that could be related to chasing prey. All burst speed events during the day were across the substrate, while at night these occurred in the water column. Overall, diel differences in water column use, along with the presence of oscillatory behaviour and burst speed events suggest that N. cepedianus are nocturnal foragers, but may opportunistically attack prey they happen to encounter during the day.     

Scale and pattern of broadnose sevengill shark Notorynchus cepedianus movement in estuarine embayments

The detailed movements of 32 acoustically tagged broadnose sevengill shark Notorynchus cepedianus were documented in and around north-east Pacific Ocean estuarine embayments from 2005 to 2007. Arrangements of passive acoustic receivers allowed analysis of movement at several spatial scales, with sex and size examined as possible factors influencing the pattern and timing of these movements. Notorynchus cepedianus exhibited a distinctly seasonal pattern of estuary use over three consecutive years, entering Willapa Bay in the spring, residing therein for extended periods of time during the summer and dispersing into nearshore coastal habitats and over the continental shelf during the autumn. Notorynchus cepedianus within Willapa Bay showed spatio-temporal patterns of segregation by size and sex, with males and small females using peripheral southern estuary channels early in the season before joining large females, who remained concentrated in central estuary channels for the entire season. Individuals displayed a high degree of fidelity not only to Willapa Bay (63% were documented returning over three consecutive seasons), but also to specific areas within the estuary, showing consistent patterns of site use from year to year. Cross-estuary movement was common during the summer, with most fish also moving into an adjacent estuarine embayment for some extent of time. Most winter and autumn coastal detections of N. cepedianus were made over the continental shelf near Oregon and Washington, U.S.A., but there were also examples of individuals moving into nearshore coastal habitats further south into California, suggesting the feasibility of broad-scale coastal movements to known birthing and nursery grounds for the species. These findings contribute to a better understanding of N. cepedianus movement ecology, which can be used to improve the holistic management of this highly mobile apex predator in regional ecosystems.     

Ultrasound examination and behavior scoring of captive broadnose sevengill sharks,Notorynchus cepedianus (Peron, 1807)

Serial ultrasound examination of four mature female sevengill sharks (Notorynchus cepedianus) was carried out over 18 months. Monitoring the reproductive cycle and development of follicles and fetuses in sharks in a noninvasive manner using this technique has not been reported previously. Sharks were caught out of the “Oceanarium” tank by divers using a specially made catch‐out bag, and brought to a holding area for examination. A behavior scoring system was used to monitor the impact of regular handling on the well‐being of the animals. Ultrasound showed the growth and regression of follicles in sevengill ovaries, and allowed an approximation of the reproductive stage of these sharks. Monitoring behavior at five time points during the procedure showed that regular handling of sharks for clinical studies could be done with minimal impact on animal welfare. The ability to follow reproductive events in elasmobranches using ultrasonography is an important step in the application of assisted reproductive technology in these species. Assisted reproductive technology, such as monitoring female reproductive cycles and artificial insemination, could potentially be used to maintain genetic diversity and compliment aquaria‐based breeding programs for endangered species such as the gray nurse shark (Carcharias taurus). Zoo Biol 26:383–395, 2007. © 2007 Wiley‐Liss, Inc.     

Seasonal occurrence and population structure of the broadnose sevengill shark Notorynchus cepedianus in coastal habitats of south-east Tasmania

Research longline sampling was conducted seasonally from December 2006 to February 2009 to investigate the occurrence and population structure of the broadnose sevengill shark Notorynchus cepedianus in coastal areas of south-east Tasmania. Notorynchus cepedianus showed a consistent temporal trend in seasonal occurrence in Norfolk Bay characterized by high abundances in summer to near absence in winter. This pattern was less pronounced in the Derwent Estuary, where fish were still caught during winter. The absence of smaller total length (L(T) ) classes (<80 cm) from the catches suggests that N. cepedianus are not using these coastal habitats as nursery areas. Of the 457 individuals tagged, 68 (15%) were recaptured. Time at liberty ranged from 6 days to almost 4 years and all but one of the recaptures were caught in its original tagging location, suggesting site fidelity. The large number of N. cepedianus in these coastal systems over summer indicates that these areas are important habitats for this species and that N. cepedianus may have a significant influence on community dynamics through both direct and indirect predator-prey interactions.     

Seasonal variation in occurrence of the sevengill shark,Notorynchus cepedianus,in two inshore habitats of southern New Zealand

Despite being a large, relatively abundant predator, the distribution and seasonal occurrence of the broadnose sevengill shark, Notorynchus cepedianus, in New Zealand is poorly understood. During 71 sampling trips conducted from July 2013 to May 2015, sharks were attracted to coastal sampling sites in southern New Zealand at ōtākou/Otago Harbour and Te Whaka ā Te Wera/Paterson Inlet, Stewart Island, using chum. Using a logistic regression model, water temperature was identified as a key predictor of encountering sevengill sharks. In addition, location, cloud cover and sea state were also identified as influential predictors. At ōtākou, a clear seasonal pattern of sevengill shark sightings emerged. Sharks were detected on 86% of survey trips in summer, whilst no sharks were detected in winter or spring. At Te Whaka ā Te Wera, sharks were sighted throughout all seasons, but a decline in shark encounters occurred during winter. This study represents the first systematic data on seasonal habitat use by sevengill sharks in New Zealand.     

Habitat use,seasonality and demography of the broadnose sevengill shark Notorynchus cepedianus in central Patagonia: Another piece of the puzzle

The habitat use, seasonality and demography of the broadnose sevengill shark Notorynchus cepedianus were investigated in central Patagonia, where a data gap exists for the species. Catch and effort and video‐derived indices indicated high relative abundance of sharks during warm months. Video stations revealed differences in the spatial use by sharks, being more frequently observed in the inner section of the bay. Complementary tagging efforts evidenced both a seasonal residence pattern and site fidelity between consecutive warm seasons. Juveniles outnumbered adults, which suggests that they may use the study area as a secondary nursing ground. Evidence from spontaneous regurgitation further suggests that prey abundance may be driving the seasonal occurrence of sharks in the region. This study allows for a more comprehensive understanding of the population structure and dynamics of sevengill sharks in the Southwest Atlantic. Abstract in Spanish is available with online material.     

Highest catch of the vulnerable broadnose sevengill shark Notorynchus cepedianus in the south‐west Atlantic

An exceptional catch of 97 broadnose sevengill sharks Notorynchus cepedianus in Samborombón Bay, Argentina, in 2013 is described from a single overnight gillnet fishing operation. Sixty‐five female and 32 male N. cepedianus, ranging in size between 105–201 and 112–190 cm L_T, respectively, were recorded in this catch. Fishers' observations and published information suggest that this species aggregates in the area seasonally for feeding.     

Genetic Diversity and Population Structure of the Pelagic Thresher Shark (Alopias pelagicus) in the Pacific Ocean: Evidence for Two Evolutionarily Significant Units

There has been an increasing concern about shark overexploitation in the last decade, especially for open ocean shark species, where there is a paucity of data about their life histories and population dynamics. Little is known regarding the population structure of the pelagic thresher shark, Alopias pelagicus. Though an earlier study using mtDNA control region data, showed evidence for differences between eastern and western Pacific populations, the study was hampered by low sample size and sparse geographic coverage, particularly a lack of samples from the central Pacific. Here, we present the population structure of Alopias pelagicus analyzing 351 samples from six different locations across the Pacific Ocean. Using data from mitochondrial DNA COI sequences and seven microsatellite loci we found evidence of strong population differentiation between western and eastern Pacific populations and evidence for reciprocally monophyly for organelle haplotypes and significant divergence of allele frequencies at nuclear loci, suggesting the existence of two Evolutionarily Significant Units (ESU) in the Pacific Ocean. Interestingly, the population in Hawaii appears to be composed of both ESUs in what seems to be clear sympatry with reproductive isolation. These results may indicate the existence of a new cryptic species in the Pacific Ocean. The presence of these distinct ESUs highlights the need for revised management plans for this highly exploited shark throughout its range.     

Preliminary Observations on the Characteristics of the Owned Dog Population in Roseau,Dominica

The subject of sanctuaries for chimpanzees has lately become the topic of a great deal of discussion (Brent, Butler, &; Haberstroh, 1997; Committee on Long-Term Care of Chimpanzees, 1997; Dyke, Williams-Blangero, Mamelka, &; Goodwin, 1995; Peterson &; Goodall, 1993). In the United States, laboratories that use chimpanzees in research are facing a housing crisis. An increase in captive births caused by the initiation of the National Chimpanzee Breeding and Research Program in 1986 (Hobson, Graham, &; Rowell, 1991), coupled with the diminished use of chimpanzees as experimental subjects, have led to a large population of chimpanzees considered to be surplus to demand (Blood, Wolfle, &; Whitney, 1992). These chimpanzees, as well as an unknown number from the private sector, are candidates for what is currently being called retirement.     

Genetic Population Structure of Pacific Hake, Merluccius productus, in the Pacific Northwest

This study presents the first protein electrophoretic study of population structure within the Georgia Basin Pacific hake Distinct Population Segment, as defined under the U.S. Endangered Species Act. Forty-one allozyme loci (29 polymorphic) were analyzed in samples from three Pacific hake spawning populations on the west coast of North America: (1) Port Susan, Puget Sound, Washington (three temporal samples); (2) south-central Strait of Georgia, British Columbia, Canada (two temporal samples); and (3) offshore of southern California (two temporal samples) (total n = 664). Mean heterozygosity over all loci was 12–13% for all populations. Within-population temporal samples were not significantly different from one another, but statistically significant differences were detected at 15 of the 29 polymorphic loci (p < 0.05) among the three populations. Differences at eight of these loci were highly significant (p < 0.001): ADA ^*, ALAT ^*, bGALA ^*, GPI-A ^*, sIDHP ^*, LDH-A ^*, MPI ^*, and PEP-B ^*. The two Georgia Basin populations were significantly different at six loci: bGALA ^*, sIDHP ^*, LDH-A ^*, MPI ^*, PGK ^*, and PGM-2 ^* (p < 0.05). Nei's genetic distance (D) was 0.0006 between Port Susan and Strait of Georgia pooled temporal samples, and 0.005 between these populations and offshore Pacific hake. F_ST was 0.02 and 0.0046 among all three populations and among the Georgia Basin populations, respectively. Both F_ST estimates were significantly greater than zero, and the results suggest a high degree of demographic isolation among all three populations.     

Molecular Population Genetics and Phenotypic Diversification of Two Populations of the Thermophilic Cyanobacterium Mastigocladus laminosus

We investigated the distributions of genetic and phenotypic variation for two Yellowstone National Park populations of the heterocyst-forming cyanobacterium Mastigocladus (Fischerella) laminosus that exhibit dramatic phenotypic differences as a result of environmental differences in nitrogen availability. One population develops heterocysts and fixes nitrogen in situ in response to a deficiency of combined nitrogen in its environment, whereas the other population does neither due to the availability of a preferred nitrogen source. Slowly evolving molecular markers, including the 16S rRNA gene and the downstream internal transcribed spacer, are identical among all laboratory isolates from both populations but belie considerable genetic and phenotypic diversity. The total nucleotide diversity at six nitrogen metabolism loci was roughly three times greater than that observed for the human global population. The two populations are genetically differentiated, although variation in performance on different nitrogen sources among genotypes could not be explained by local adaptation to available nitrogen in the respective environments. Population genetic models suggest that local adaptation is mutation limited but also that the populations are expected to continue to diverge due to low migratory gene flow.     

Population Genetics of Vibrio vulnificus: Identification of Two Divisions and a Distinct Eel-Pathogenic Clone

Genetic relationships among 62 Vibrio vulnificus strains of different geographical and host origins were analyzed by multilocus enzyme electrophoresis (MLEE), random amplification of polymorphic DNA (RAPD), and sequence analyses of the recA and glnA genes. Out of 15 genetic loci analyzed by MLEE, 11 were polymorphic. Cluster analysis identified 43 distinct electrophoretic types (ETs) separating the V. vulnificus population into two divisions (divisions Ι and ΙΙ). One ET (ET 35) included all indole-negative isolates from diseased eels worldwide (biotype 2). A second ET (ET 2) marked all of the strains from Israel isolated from patients who handled St. Peter's fish (biotype 3). RAPD analysis of the 62 V. vulnificus isolates identified 26 different profiles separated into two divisions as well. In general, this subdivision was comparable (but not identical) to that observed by MLEE. Phylogenetic analysis of 543 bp of the recA gene and of 402 bp of the glnA gene also separated the V. vulnificus population into two major divisions in a manner similar to that by MLEE and RAPD. Sequence data again indicated the overall subdivision of the V. vulnificus population into different biotypes. In particular, indole-negative eel-pathogenic isolates (biotype 2) on one hand and the Israeli isolates (biotype 3) on the other tended to cluster together in both gene trees. None of the methods showed an association between distinct clones and human clinical manifestations. Furthermore, except for the Israeli strains, only minor clusters comprising geographically related isolates were observed. In conclusion, all three approaches (MLEE, RAPD, and DNA sequencing) generated comparable but not always equivalent results. The significance of the two divisions (divisions Ι and ΙΙ) still remains to be clarified, and a reevaluation of the definition of the biotypes is also needed.     

MHC及其在种群遗传学和保护遗传学中的应用

主要组织相容性复合体（major histocompatibility complex,MHC）是脊椎动物体内与免疫应答调节密切相关的一个基因家族,是基因组中多态性最丰富的区域。通过MHC的遗传变异分析可以提供物种的遗传多样性水平、进化历史和种群动态,以及种群遗传结构等信息,并在濒危物种饲养繁殖种群的遗传管理中有重要应用。 MHC and Its Application in the Population and Conservation Genetics YANG Guang,CHEN Xu-yan,REN Wen-hua,YAN Jie Institute of Genetic Resources,Nanjing Normal University,Nanjing 210097,China Abstract:The major histocompatibility complex (MHC),with the highest genetic polymorphism,is a cluster of genes involved in immune response regulation in the vertebrates.MHC can provide information such as population genetic diversity,evolutionary history and population dynamics,and population genetic structure etc.It can also be applied in the captive breeding programme for endangered vertebrate species. Key words：major histocompatibility complex (MHC);genetic diversity,population viability;population genetic structure;captive breeding     

Biomagnification of Mercury and Selenium in Blue Shark Prionace glauca from the Pacific Ocean off Mexico

The aim of this study was to determine the biomagnification of mercury through the principal prey of the blue shark, Prionace glauca, off the western coast of Baja California Sur, Mexico, as well as the relationship between mercury and selenium in blue sharks. High levels of mercury were found in shark muscle tissues (1.39?±?1.58?μg/g wet weight); these values are above the allowed 1.0?μg/g for human consumption. The mercury to selenium molar ratio was 1:0.2. We found a low correlation between mercury bioaccumulation and shark size. Juveniles have lower concentrations of mercury than adults. Regarding the analyzed prey, the main prey of the blue shark, pelagic red crab, Pleuroncodes planipes, bioaccumulated 0.04?±?0.01?μg/g Hg wet weight, but the prey with higher bioaccumulation was the bullet fish Auxis spp. (0.20?±?0.02?μg/g wet weight). In terms of volume, the red crab P. planipes can be the prey that provides high levels of mercury to the blue shark.     

Population Genetics of Plasmodium vivax in the Peruvian Amazon

Background

Characterizing the parasite dynamics and population structure provides useful information to understand the dynamic of transmission and to better target control interventions. Despite considerable efforts for its control, vivax malaria remains a major health problem in Peru. In this study, we have explored the population genetics of Plasmodium vivax isolates from Iquitos, the main city in the Peruvian Amazon, and 25 neighbouring peri-urban as well as rural villages along the Iquitos-Nauta Road.

Methodology/ Results

From April to December 2008, 292 P. vivax isolates were collected and successfully genotyped using 14 neutral microsatellites. Analysis of the molecular data revealed a similar proportion of monoclonal and polyclonal infections in urban areas, while in rural areas monoclonal infections were predominant (p = 0.002). Multiplicity of infection was higher in urban (MOI = 1.5–2) compared to rural areas (MOI = 1) (p = 0.003). The level of genetic diversity was similar in all areas (He = 0.66–0.76, p = 0.32) though genetic differentiation between areas was substantial (PHI_PT = 0.17, p<0.0001). Principal coordinate analysis showed a marked differentiation between parasites from urban and rural areas. Linkage disequilibrium was detected in all the areas (IAs = 0.08–0.49, for all p<0.0001). Gene flow among the areas was stablished through Bayesian analysis of migration models. Recent bottleneck events were detected in 4 areas and a recent parasite expansion in one of the isolated areas. In total, 87 unique haplotypes grouped in 2 or 3 genetic clusters described a sub-structured parasite population.

Conclusion/Significance

Our study shows a sub-structured parasite population with clonal propagation, with most of its components recently affected by bottleneck events. Iquitos city is the main source of parasite spreading for all the peripheral study areas. The routes of transmission and gene flow and the reduction of the parasite population described are important from the public health perspective as well for the formulation of future control policies.     

Population Genetics and Phylogeography of Bufo gargarizans in China

The Chinese toad Bufo gargarizans has an extensive range, covering nearly all of China. This study addresses the population genetic structure of this toad and the relation to geographic location. Partial sequences of the mtDNA control region were obtained from 14 populations, 29 haplotypes were defined, and 73 variable sites were found, including 66 parsimony informative sites. All population genetic analyses indicated no clear geographic pattern in the distribution of haplotypes. The genetic divergence between the populations was significant. Phylogeographic analyses suggested that past fragmentation and/or long-distance colonization seemed to have shaped the present-day distribution of the haplotypes of B. gargarizans.     

Relatedness,Conflict, and the Evolution of Eusociality

The evolution of sterile worker castes in eusocial insects was a major problem in evolutionary theory until Hamilton developed a method called inclusive fitness. He used it to show that sterile castes could evolve via kin selection, in which a gene for altruistic sterility is favored when the altruism sufficiently benefits relatives carrying the gene. Inclusive fitness theory is well supported empirically and has been applied to many other areas, but a recent paper argued that the general method of inclusive fitness was wrong and advocated an alternative population genetic method. The claim of these authors was bolstered by a new model of the evolution of eusociality with novel conclusions that appeared to overturn some major results from inclusive fitness. Here we report an expanded examination of this kind of model for the evolution of eusociality and show that all three of its apparently novel conclusions are essentially false. Contrary to their claims, genetic relatedness is important and causal, workers are agents that can evolve to be in conflict with the queen, and eusociality is not so difficult to evolve. The misleading conclusions all resulted not from incorrect math but from overgeneralizing from narrow assumptions or parameter values. For example, all of their models implicitly assumed high relatedness, but modifying the model to allow lower relatedness shows that relatedness is essential and causal in the evolution of eusociality. Their modeling strategy, properly applied, actually confirms major insights of inclusive fitness studies of kin selection. This broad agreement of different models shows that social evolution theory, rather than being in turmoil, is supported by multiple theoretical approaches. It also suggests that extensive prior work using inclusive fitness, from microbial interactions to human evolution, should be considered robust unless shown otherwise.     

Relatedness, phylogeny, and evolution of the fungi

Recent advances in fungal systematics are reviewed in relation to our previous studies. The usefulness of the integrated analysis of genotypic (especially 18S rRNA gene sequence comparisons) and phenotypic (especially ultrastructural and chemotaxonomic data) characters has been emphasized for the major groups and selected taxa of the fungi, and the impact to fungal systematics and evolution is discussed. Our noteworthy studies and findings are: 1) polyphyly of the chytridiomycetes and zygomycetes, 2) phylogenetic origin of the entomophthoralean fungi includingBasidiobolus, 3) detection of a major new lineage “Archiascomycetes,” comprisingTaphrina, Protomyces andSaitoella, Schizosaccharomyces, andPneumocystis, within the Ascomycota, and its phylogenetic and evolutionary significance, 4) polyphyletic origins of species in the anamorphic genusGeosmithia, and 5) phylogenetic placement ofMixia osmundae, species correctly and incorrectly assigned to the genusTaphrina, and basidiomyceotus yeasts. The newest 18S rDNA sequence-based neighbor-joining trees of the Ascomycota are demonstrated. “Traditional studies of evolution have amply demonstrated that evolution at the phenotypic level is characterized by adaptation and opportunism, irregularity in pace, and inequality of rates among lineages. In contrast, studies of molecular evolution have revealed quite different features characterized by changes that are conservative in nature, random in pattern (independent of phenotypic characters), and quite regular in pace with equal rates among diverge [sic] lineages for a given protein”. (Kimura, M. 1983. The neutral theory of molecular evolution, pp. 308–309, Cambridge University Press, Cambridge.) Recipient of the 2nd Mycological Society of Japan's Excellent Achievement Award, 1998; the awarding lecture was given at the 42nd Annual Meeting of the Mycological Society of Japan, 16 May, 1998, Kyoto University, Kyoto. This review is based mainly on the publications intended for the Award.