Age and growth of Neotrygon picta, Neotrygon annotata and Neotrygon kuhlii from north-east Australia, with notes on their reproductive biology

Vertebral band formations were used to define age and growth in three Neotrygon species caught regularly as by-catch in prawn trawl fisheries in north-east Australia. Centrum edge and marginal increment ratio analyses were used to validate annual band formations. Age estimates ranged from 1 to 18 years, with the von Bertalanffy growth function considered to have the best fit to Neotrygon picta (males, W(D∞) = 271 mm, k = 0·12; females, W(D∞) = 360·5 mm, k = 0·08) and Neotrygon kuhlii (males, W(D∞) = 438·6 mm, k = 0·08; females, W(D∞) = 440·6 mm, k = 0·08) disc width (W(D))-at-age data. The Gompertz growth function had the best fit to Neotrygon annotata W(D)-at-age data (males, W(D∞) = 230·4 mm, k = 0·20; females, W(D∞) = 265·5 mm, k = 0·31). Age at sexual maturity ranged from 3 to 6 years, with N. picta having the smallest size at birth (100 mm W(D)), smallest W(D) at 50% maturity (W(D50): male, 172 mm, female, 180·7 mm) and lowest age at sexual maturity (3-4 years). This study helps redefine and improve the accuracy of fisheries-based risk assessments for these small species with relatively conservative life-history variables.     

Evidence for reproductive philopatry in the bull shark Carcharhinus leucas

Reproductive philopatry in bull sharks Carcharhinus leucas was investigated by comparing mitochondrial (NADH dehydrogenase subunit 4, 797 base pairs and control region genes 837 base pairs) and nuclear (three microsatellite loci) DNA of juveniles sampled from 13 river systems across northern Australia. High mitochondrial and low microsatellite genetic diversity among juveniles sampled from different rivers (mitochondrial φ(ST) = 0·0767, P < 0·05; microsatellite F(ST) = -0·0022, P > 0·05) supported female reproductive philopatry. Genetic structure was not further influenced by geographic distance (P > 0·05) or long-shore barriers to movement (P > 0·05). Additionally, results suggest that C. leucas in northern Australia has a long-term effective population size of 11 000-13 000 females and has undergone population bottlenecks and expansions that coincide with the timing of the last ice-ages.     

Is hunting mortality additive or compensatory to natural mortality? Effects of experimental harvest on the survival and cause-specific mortality of willow ptarmigan

1. The effects of harvest on the annual and seasonal survival of willow ptarmigan Lagopus lagopus L. were tested in a large-scale harvest experiment. Management units were randomly assigned to one of three experimental treatments: 0%, 15% or 30% harvest. Seasonal quotas were based on the experimental treatment and estimates of bird density before the hunting season. Survival rates and hazard functions for radio-marked ptarmigan were then estimated under the competing risks of harvest and natural mortality. 2. The partially compensatory mortality hypothesis was supported: annual survival of ptarmigan was 0·54 ± 0·08 SE under 0% harvest, 0·47 ± 0·06 under 15% harvest, and was reduced to 0·30 ± 0·05 under 30% harvest. Harvest mortality increased linearly from 0·08 ± 0·05, 0·27 ± 0·05 and 0·42 ± 0·06 from 0% to 30% harvest, whereas natural mortality was 0·38 ± 0·08, 0·25 ± 0·05 and 0·28 ± 0·06 under the same treatments. 3. Realized risk of harvest mortality was 0·08-0·12 points higher than our set harvest treatments of 0-30% because birds were exposed to risk if they moved out of protected areas. The superadditive hypothesis was supported because birds in the 30% harvest treatment had higher natural mortality during winter after the hunting season. 4. Natural mortality was mainly because of raptor predation, with two seasonal peaks in fall and spring. Natural and harvest mortality coincided during early autumn with little potential for compensation during winter months. Peak risk of harvest mortality was 5× higher than natural mortality. Low natural mortality during winter suggests that most late season harvest would be additive mortality. 5. Environmental correlates of natural mortality of ptarmigan included seasonal changes in snow cover, onset of juvenile dispersal, and periods of territorial activity. Natural mortality of ptarmigan was highest during autumn movements and nesting by gyrfalcons Falco rusticolus L. Mortality was low when gyrfalcons had departed for coastal wintering sites, and during summer when ptarmigan were attending nests and broods. 6. Our experimental results have important implications for harvest management of upland gamebirds. Seasonal quotas based on proportional harvest were effective and should be set at ≤ 15% of August populations for regional management plans. Under threshold harvest of a reproductive surplus, 15% harvest would be sustainable at productivity rates ≥ 2·5 young per pair. Impacts of winter harvest could be minimized by closing the hunting season in early November or by reducing late season quotas.     

Age and growth of the tiger shark Galeocerdo cuvier off the east coast of Australia

Total lengths (L_T) at age and growth rates for south‐west Pacific Galeocerdo cuvier were estimated from vertebral growth‐band counts of 202 sagitally sectioned centra from 112 females (71–430 cm L_T), 79 males (72–351 cm L_T) and 11 of unknown sex. Captive growth data were also examined to complement vertebral age estimations. The sexes combined modelled growth coefficient (k = 0·08) was smaller than previously reported for G. cuvier populations elsewhere. Split‐band and narrow banding patterns were identified as potential sources of age underestimation in this species.     

盐分和母树大小对黑松海防林种子萌发和幼苗早期生长的影响

研究了盐度(0、0.02、0.04和0.08 mol·L~(-1))和黑松母树大小对山东半岛北部海防林的主要造林树种黑松种子萌发和幼苗早期生长的影响.结果表明:盐度对黑松种子的发芽率有显著影响,随着NaCl浓度的升高,种子萌发率逐渐下降;盐分抑制黑松幼苗的早期生长,随着盐浓度升高,黑松幼苗的根长、芽长及根干质量均显著降低;母树大小在总体上对种子萌发率没有影响,但显著影响黑松幼苗的根长、芽长和芽干质量;盐度和母树大小的相互作用显著影响黑松幼苗的根长和芽长.而对黑松种子萌发率、幼苗根干质量和芽干质量的影响不显著.

Abstract：

Pinus thunbergii is the main forestation tree species of coastal protection forests in northern Shandong Peninsula of China. Its seed germination and seedling early growth were stud-ied under the conditions of different water salinity (0, 0. 02, 0. 04, and 0. 08 mol·L~(-1)) and mother tree sizes. With increasing sea water salinity, the seed germination rate, root-and plu-mule length, and the dry weights of root and plumule decreased significantly. Mother tree size had little effects on the seed germination rate, but affected the root-and plumule length and the plumule dry weight significantly. The interaction of sea water salinity and mother tree size affect-ed the root-and plumule length significantly, but less affected the germination rate and the dry weights of root and plumule.     

Carbon isotope ratios of crassulacean acid metabolism species in relation to climate and phytosociology

Summary The ¹³C, values of the two principal, widely distributed CAM species in Big Bend National Park, Texas, were examined and related to phytosociologic and macroclimatic parameters. Samples of Agave lecheguilla and Opuntia engelmannii were collected along an elevational gradient covering 1370 m, and values for both total and insoluble fractions were measured. Linear regressions were used to correlate changes in values with changes in community importance and mean annual precipitation for both species to determine whether or not they became increasingly C₃-like in their photosynthetic mode at more mesic, upper elevations. In addition, values were measured for other Agave and Opuntia species from different locations and for different seasons and for A. lecheguilla following a short laboratory experiment. Results show that there are very small changes in values for both species along the pronounced temperature and precipitation gradients associated with elevational change. The ranges in values for O. engelmannii are only 1.5 (n=7) and 1.2 (n=6) for total and insoluble fractions respectively. The ranges in values for A. lecheguilla are 2.6 (n=9) and 3.1 (n=9). The results for other species confirm this low variability. We conclude that the species examined are obligate CAM species and that wide elevational distributions are not due to shifts in photosynthetic mode.     

Biological observations on the crocodile shark Pseudocarcharias kamoharai

Sex ratios and gravid characteristics were analysed for the crocodile shark Pseudocarcharias kamoharai from the tropical eastern Pacific Ocean. Gravid females ranged from 80 to 102 cm fork length (L(F) ). The mode litter size was four (two embryos per uterus), mean embryo length was linearly correlated with maternal length (r = 0·465, n = 32); there was no significant difference in L(F) between female and male embryos.     

Prevalence and co-infection of Toxoplasma gondii and Neospora caninum in Apodemus sylvaticus in an area relatively free of cats

The protozoan parasite Toxoplasma gondii is prevalent worldwide and can infect a remarkably wide range of hosts despite felids being the only definitive host. As cats play a major role in transmission to secondary mammalian hosts, the interaction between cats and these hosts should be a major factor determining final prevalence in the secondary host. This study investigates the prevalence of T. gondii in a natural population of Apodemus sylvaticus collected from an area with low cat density (<2·5 cats/km2). A surprisingly high prevalence of 40·78% (95% CI: 34·07%-47·79%) was observed despite this. A comparable level of prevalence was observed in a previously published study using the same approaches where a prevalence of 59% (95% CI: 50·13%-67·87%) was observed in a natural population of Mus domesticus from an area with high cat density (>500 cats/km2). Detection of infected foetuses from pregnant dams in both populations suggests that congenital transmission may enable persistence of infection in the absence of cats. The prevalences of the related parasite, Neospora caninum were found to be low in both populations (A. sylvaticus: 3·39% (95% CI: 0·12%-6·66%); M. domesticus: 3·08% (95% CI: 0·11%-6·05%)). These results suggest that cat density may have a lower than expected effect on final prevalence in these ecosystems.     

Feeding ecology and dietary comparisons among three sympatric Neotrygon (Myliobatoidei: Dasyatidae) species

The diets of Neotrygon picta, Neotrygon kuhlii and Neotrygon annotata are described using trophic level analysis, index of relative importance (I(RI) ) and non-metric multidimensional scaling ordination (nMDS). They were secondary consumers with trophic levels of between 3·55 and 3·58. Carids were the most important prey category in the diets of N. picta (82·0%I(RI) ) and N. annotata (69·4%I(RI) ); Polychaeta (72·3%I(RI) ) was the most important prey category for N. kuhlii. A significant difference was detected between the volumetric dietary data of all three species (ANOSIM, global R-statistic = 0·742, P < 0·01) and between sequential N. picta and N. kuhlii size classes (ANOSIM, global R-statistics = 0·367-0·403, P < 0·01). Changes in polychaete and carid prey proportions were the primary sources of diet variability. Dietary differences may be linked to variations in disc width, mouth morphology and feeding strategies. This study provides insights into the level of variability within and between the diets and feeding behaviours of Neotrygon species, and the potential for resource partitioning to occur when these species coexist.     

不同激素配比和AgNO3对两种基因型大白菜子叶离体再生的影响

以‘08S555’和‘陕秋白’大白菜子叶为外植体,研究了激素配比和AgNO3对不定芽再生的影响。结果表明：‘陕秋白’的再生率高于‘08S555’,但出芽系数比‘08S555’低。在6-BA与NAA组合时,‘陕秋白’再生率最高,为68.33%,‘08S555’为28.33%;再生系数分别为1.09和2.81。在TDZ与NAA组合时,二者不定芽的再生频率分别为79.17%和45.83%;再生系数分别为1.24和2.55。这说明与6-BA相比,TDZ与NAA组合对两个大白菜子叶再生率的效果更好。AgNO3与细胞分裂素及生长素配合使用,能提高‘陕秋白’子叶不定芽的再生频率。当TDZ浓度为0.3mg·L^-1、NAA为0.5mg·L^-1和AgNO3为6mg·L^-1时,‘陕秋白’再生率最高,达到87.50%。     

Assessing the overlap between the diet of a coastal shark and the surrounding prey communities in a sub-tropical embayment

An elasmobranch survey of sub-tropical Hervey Bay, Australia, captured the slit-eye shark Loxodon macrorhinus at only one of three sites sampled. The dietary composition of this small shark species was compared to the prey communities within Hervey Bay to test whether prey availability was driving this observation. Dietary analysis of prey groups revealed that teleosts dominated the diet, per cent index of relative importance, % I(RI) (79·5%) and per cent geometric index of importance, % G(II) (52·7%), with shrimp-like invertebrates and cephalopods identified as the most important invertebrate prey groups. Baited remote underwater video (BRUV) used to sample prey communities at each site, demonstrated a highly diverse and significantly different community composition among the sites. There was no significant overlap between the diet of L. macrorhinus and any of the prey communities detected by BRUVs according to one-way analysis of similarities and the simplified Morisita index. Habitat electivity analysis revealed affinity of L. macrorhinus for the site with the highest water clarity (Secchi disc depth), opposing that of three other shark species. Overall, the results suggest that the distribution of L. macrorhinus is not driven by prey availability but other factors such as water clarity, predator avoidance or a reduction in interspecies competition.     

张家界大鲵生境特征

2006—2008年的7—8月,对湖南张家界大鲵国家级自然保护区境内大鲵栖息河段及其洞穴特征、水质和饵料生物资源进行了实地观测和取样分析,研究了该保护区野生大鲵的生境特征.结果表明：研究区大鲵栖息河段海拔适中,在（373±97） m,河宽与河深均较小,分别为（6.39±2.13） m和（1.07±0.53) m;河段底质均为石质性结构,多为卵石或礁石,河床多为不规则型,河岸多为石壁;两岸植被类型多为灌木丛,植被覆盖度（>50% ）与坡度［（58±17）°］均较大;研究河段的水流速较大,在（0.33±0.08） m·s^-1,且人为干扰较弱.研究区大鲵栖息地的洞穴数量较多,达（4±2）个·100 m^-1,洞穴中水的流速较小,在（0.22±0.10） m·s^-1.大鲵栖息处水质溶解氧较高,为（7.23±0.85） mg·L^-1,化学耗氧量与总氮含量均较低,分别为（4.00±2.51）和（0.11±0.15） mg·L^-1,总硬度适中,为（137.16±67.69） mg·L^-1,大肠菌群较少,为（3419±3407） ind·L^-1.对研究区大鲵种群数量影响最大的饵料生物是蟹,其次为虾.     

Geographical distribution of schistosomiasis and soil-transmitted helminths among school children in informal settlements in Kisumu City, Western Kenya

This cross-sectional study determined the prevalence and distribution of schistosome and soil-transmitted helminth (STH) infections among 1,308 children aged 10-18 years in 34 primary schools in 8 informal urban settlements in Kisumu City, western Kenya. Stool samples were collected and examined for eggs of Schistosoma mansoni and STH (Hookworms, Ascaris lumbricoides and Trichuris trichiura) using the Kato-Katz technique. Haematuria was used as a proxy indicator of urinary schistosomiasis. Schools and water bodies were mapped using a geographical information system. Overall, 34% of children were infected with one or more helminth species whereas 16·2% of children were infected with one or more STH species. Schools in closest proximity to Lake Victoria and River Nyamasaria had the highest S. mansoni prevalence while schools with STH were more homogenously distributed. Mean school prevalence of S. mansoni infection was 21% (range=0-69·7%), S. haematobium 3·6% (range=0-12%), hookworms 6·1% (range=0-20%), A. lumbricoides 4·9% (range=0-18·4%), and T. trichiura 7·7% (range=0-18·6%). Helminth-related morbidities were not associated with infection. Our study demonstrates that schistosomiasis and STH are important health priorities among schools in informal settlements of Kisumu City, and highlights the need for routine deworming in similar settings.     

苦苣菜属5种植物的黄酮类成分含量分析

菊科（Compositae）苦苣菜属（Sonchus L．）的许多种类在民间作为药用植物使用,大多具有清热解毒、消肿排脓及凉血利湿等功效。苦苣菜属植物主要含有黄酮类及倍半萜类活性成分,其中苦苣菜（S．oleraceus L．）中的总黄酮对脑缺血缺氧小鼠及实验性肝损伤均有明显的保护作用。     

Mother-offspring isotope fractionation in two species of placentatrophic sharks

Stable-isotope values of a scalloped hammerhead Sphyrna lewini and blacktip shark Carcharhinus limbatus and their respective embryos were analysed. Embryos of both species were enriched in δ(15) N compared to their mothers (0·82 and 0·88‰, respectively), but fractionation of δ(13) C varied. Embryonic S. lewini were enriched (1·00‰) in δ(13) C while C. limbatus were depleted (0·27‰) relative to their mothers.     

Heterozygosity-fitness correlations in the gilthead sea bream Sparus aurata using microsatellite loci from unknown and gene-rich genomic locations

Heterozygosity-fitness correlations (HFC) were assessed for a sample of a gilthead sea bream Sparus aurata population. Two hundred and seventy-one fish were genotyped at 22 known and novel microsatellite loci, from which correlations between the multilocus heterozygosity index (I(MLH) ) and various fitness traits (fork length, mass and specific growth rates) were calculated. Significant global HFCs were found in this sample (0·02 ≤r(2) ≤ 0·08). In addition, all the significant correlations found in this work were negative, indicating that heterozygotes had lower fitness than their homozygote counterparts. Marker location could not explain the observed HFCs. Evidence of inbreeding, outbreeding or population and family structuring was not found in this work. The presence of undetected general effects that may lead to the appearance of HFCs, however, cannot be ruled out. These results seem to be best explained by the occurrence of local effects (due to linkage) or even by possible direct locus advantages.     

燕山山脉不同居群豆茶决明的种子形态及营养成分比较

豆茶决明也Cassia nomame ( Sieb.) Kitag.页为云实科( Caesalpiniaceae)决明属( Cassia Linn.)一年生草本植物[1],其地上部分及种子可入药,主治水肿、肾炎、慢性便秘、咳嗽和痰多等,并具有驱虫、健胃之功效,也可代茶饮用[2],在药理和保健方面具有多重功效,是极具开发潜力的野生植物资源。目前仅燕山山脉的河北省青龙满族自治县每年就有近1000 t的豆茶决明全草出口,而且燕山山脉民间还有用豆茶决明种子做酱的习惯,致使豆茶决明野生资源面临枯竭的境地。目前,对豆茶决明的研究还非常有限,尤其在资源调查、引种、栽培和开发等方面。     

A global review of species-specific shark-fin-to-body-mass ratios and relevant legislation

In this review, shark-fin-to-body-mass ratios, which have been legislated by several countries as a means of regulating and monitoring shark fisheries, have been compiled and reviewed. Observed and legislated wet-fin-mass-to-round-mass (M(fw) :M(r) ) ratios have been collected for 50 species and eight countries. Wet to dry-fin mass conversion factors have also been reviewed. Existing shark fishery legislation was compiled by political entity and regional fishery management organizations (RFMO). The mean observed M(fw) :M(r) ratio for all species was 3·0%, but actual fin to body-mass ratios varied considerably by species and location. Species-specific mean ratios ranged from 1·1 to 10·9%, and estimated mean ratios ranged from 1·5 to 6·1% by country, depending on fin-cutting practices and the mix of exploited species. The mean conversion factor for wet to dry-fin mass was 0·43. Shark-related legislation was found to exist in 37 countries and the 22 maritime members of the European Union, and shark-related regulations have been designated by nine RFMOs. Results suggest that currently regulated ratios may not be appropriate for all species and fin-cutting practices, and regulations based on generalized ratios for all sharks may be inadequate. Alternative policies may be necessary for the effective management of global shark fisheries.     

Are there trade-offs between pre- and post-fledging survival in black brent geese?

1.?The growth period is an important determinant of fitness later in life through its effects on first-year survival and future reproduction. Choices by adult females about where to rear their offspring strongly affect growth rates and offspring fitness in geese. 2.?Individual female black brent (Branta bernicla nigricans) tend to raise their broods in the same areas each year, and these areas are consistently ranked with respect to growth rates of goslings. Therefore, some females consistently rear their broods on areas resulting in lower post-fledging fitness. 3.?We explore the potential that growth rates of offspring (and associated fitness consequences) are traded off against other vital rates influencing fitness of either adult females or goslings. Growth of goslings primarily influences fitness after fledging, so one hypothesis is that survival before fledging, which is influenced by predation, is traded off against growth rates and post-fledging survival. 4.?We estimated pre-fledging and post-fledging survival for goslings reared on areas used by broods from the Tutakoke River black brent colony. We examined recaptures, recoveries by hunters and resightings of brent marked as goslings with webtags and standard leg rings. These data were analyzed using capture-mark-recapture models in program mark to derive separate estimates of pre- and post-fledging survival for 18 cohorts (1987-2004) of black brent goslings across seven brood rearing areas (BRAs). 5.?Estimates of pre-fledging survival probability varied from 0·00?±?0·00 (mean?±?95% confidence interval) to 0·92?±?0·1; and estimates of post-fledging survival probability varied from 0·00?±?0·00 to 1·00?±?0·08. Substantial variation existed both among BRAs and years but post-fledging survival declined substantially during the study. 6.?Pre- and post-fledging survival were positively correlated, exhibiting a quadratic relationship (?(post-fledging survival) =?1·00 (±0·47)x-0·83 (±0·480)x(2) , where x?=?pre-fledging survival). Therefore, we did not find a trade-off between pre- and post-fledging survival in black brent goslings across BRAs, suggesting that factors other than foraging conditions and predation on goslings must influence selection of BRAs.