Residence and movement patterns of cownose rays Rhinoptera bonasus within a south-west Florida estuary

Between July 2003 and November 2004, 21 cownose rays Rhinoptera bonasus were tagged and tracked within Pine Island Sound estuary, Florida, using passive acoustic telemetry. Residence time of individuals ranged between 1 and 102 days. No relationship was detected between ray activity and tidal stage or time of day. Minimum convex polygons (MCP) and kernel utilization distributions (KUD) were calculated over several time frames to demonstrate the extent of an animal's home range and core areas of use. Total MCPs ranged between 0·81 and 71·78 km² (mean = 22·01 km²), with daily MCPs as large as 25·8 km². Total 95% KUDs ranged between 0·18 and 62·44 km² (mean = 22·63 km²), while total 50% KUDs were smaller, ranging from 0·09 to 9·68 km² (mean = 3·33 km²). Both MCP and KUD areas exhibited a positive relationship with residence time and R. bonasus size. As mobile, pelagic swimmers capable of traversing large distances, these data show that cownose rays travel extensively throughout this estuary, yet may remain within very small areas for extended periods.     

Genetic evidence supports a range extension for the Brazilian cownose ray Rhinoptera brasiliensis in the western North Atlantic

We report 24 new records of the Brazilian cownose ray Rhinoptera brasiliensis outside its accepted geographic range. Sequencing of a 442-base pair portion of the mitochondrial NADH dehydrogenase subunit 2 gene for 282 Rhinoptera samples revealed eight records off the east coast of the USA and 16 from the eastern Gulf of Mexico. Both sexes of all life stages were documented in all seasons over multiple years in the Indian River and Lake Worth lagoons, Florida, indicating that their range extends further in the western North Atlantic than previously described.     

Summer and fall movement of cownose ray, <Emphasis Type="Italic">Rhinoptera bonasus</Emphasis>, along the east coast of United States observed with pop-up satellite tags

Cownose ray, Rhinoptera bonasus, is a common elasmobranch species along the southeast United States coast that recently has received negative attention. These rays can consume considerable amounts of commercial shellfish raising concerns regarding their control and need for effective management. However, limited information is known regarding their population abundance and migration patterns. We addressed the latter by reviewing 25 tagged cownose rays in Chesapeake Bay with pop-up satellite archival tags (PSATs) to study their movement patterns during summer and fall and identify wintering grounds. Eleven tags provided useful data on temperature, depth, light level and/or end locations. The migration tracks were deciphered through geolocation based on light levels, sea surface temperatures and depth constraints. PSAT end locations indicated southern wintering grounds in the coastal waters of central Florida. Female rays migrated out of Chesapeake Bay at the end of September to early October and continued their southerly migration to Florida. Male rays exited the bay in July and migrated northward based on their estimated movement tracks. The male rays appeared to have a second summer feeding ground off the coast of southern New England. In the fall, males migrated south from New England to the same wintering grounds as the females. No diel differences in habitat use were detected; however, males tended to occupy a wider depth and temperature range compared to females. Information on the movement patterns and habitat use for cownose rays will assist in determining more effective recreational and commercial management plans.     

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.     

The effect of developmental temperature on the genetic architecture underlying size and thermal clines in Drosophila melanogaster and D. simulans from the east coast of Australia

Body size and thermal tolerance clines in Drosophila melanogaster occur along the east coast of Australia. However the extent to which temperature affects the genetic architecture underlying the observed clinal divergence remains unknown. Clinal variation in these traits is associated with cosmopolitan chromosome inversions that cline in D. melanogaster. Whether this association influences the genetic architecture for these traits in D. melanogaster is unclear. Drosophila simulans shows linear clines in body size, but nonlinear clines in cold resistance. Clinally varying inversions are absent in D. simulans. Line-cross and clinal analyses were performed between tropical and temperate populations of D. melanogaster and D. simulans from the east coast of Australia to investigate whether clinal patterns and genetic effects contributing to clinal divergence in wing centroid size, thorax length, wing-to-thorax ratio, cold and heat resistance differed under different developmental temperatures (18 °C, 25 °C, and 29 °C). Developmental temperature influenced the genetic architecture in both species. Similarities between D. melanogaster and D. simulans suggest clinally varying inversion polymorphisms have little influence on the genetic architecture underlying clinal divergence in size in D. melanogaster. Differing genetic architectures across different temperatures highlight the need to consider different environments in future evolutionary and molecular studies of phenotypic divergence.     

中国东部沿海互花米草种群生活史特征的纬度变异与可塑性

互花米草(Spartina alterniflora)于20世纪70年代被引入中国,目前已在东部沿海盐沼湿地中广泛分布,成为海岸带盐沼中危害严重的入侵植物之一.为了研究互花米草在中国入侵区中的适应机制,揭示遗传分化和表型可塑性在该物种成功入侵中的作用,本研究沿纬度梯度在南起广东(22°N)、北至天津(39°N)的沿海样带上采集了10个种群的样本,通过同质园实验比较了不同纬度来源的种群在,生活史和生长特征方面是否存在遗传分化,并平行设置高低两个水位处理以比较互花米草对水位变化(不同高程生境条件)的可塑性反应.结果表明,在所研究的互花米草17个性状中有12个存在显著的种群间差异.其中,平均开花日期和相对生长率(植株高度)表现出显著的纬度梯度变异:随着纬度的升高,开花时间提前,相对生长速率(植株高度)趋于增加.同时17个性状中有9个在不同水位处理之间存在显著差异.这些结果表明,遗传分化可能是互花米草能够快速占据广阔分布区的重要原因之一,而表型可塑性可能对互花米草在小尺度上占据不同高程环境的过程有重要作用.     

Annual variation in the abundance and size of heterotrophic nanoflagellates on the SW coast of Finland, the Baltic Sea

Annual variation and vertical distribution in the abundanceand cell volume of heterotrophic nanoflagellates (HNF) was studiedon the SW coast of Finland, the Baltic Sea. HNF cell numbersand mean cell volume varied annually from 90 to 10⁴ cells ml^–1,and from 3 to 32 µm³, respectively, with maxima in earlysummer. The proportion of choanoflagellates in the HNF communitywas 0–23%. Statistical analysis revealed the verticaldifferences in HNF abundance to be insignificant, but verticaldifferences in the size structure of HNF communities were found,especially during thermal stratification. The majority (>80%)of HNF were small (maximum dimension 2–4 µm); theproportion of large (>7 µm) cells were only 2–4%of the HNF abundance. An empirical equation for the relationshipbetween HNF cell length and volume is presented, and the measurementof flagellate volume by epifluorescence microscopy is discussed.     

Growth and size distribution of some large brown algae in Ohori,east coast of Korea

About fifty individuals of four dominant large brown algae were collected by random sampling at monthly intervals using SCUBA. Size frequencies of Sargassum confusum and S. horneri were concentrated mainly in the small size classes during the initial growth phase, but were more or less evenly distributed in most size classes during the fast growing phase. Undaria pinnatifida and Costaria costata showed the same tendency as Sargassum spp., that frequency distribution became even when the plants reached their maximum growth. The kelp species recorded their maximum lengths in March, whereas Sargassum spp. showed their peaks in early summer. The relationships between the length and weight in different growth phases appeared to be dependent on the phenology of each species.     

The influence of upwelling,coastal currents and water temperature on the distribution of the red tide dinoflagellate, <Emphasis Type="Italic">Noctiluca scintillans</Emphasis>, along the east coast of Australia

Quasi-synoptic surveys along the east coast of Australia between 28 and 34°S show that the heterotrophic dinoflagellate, Noctiluca scintillans, occurs along this entire stretch of the coast. Areas of relatively high abundance of Noctiluca were observed downstream of regions predisposed to current-induced upwellings as a consequence of alongshore topographic variations. High-resolution temporal and spatial sampling of upwelling events showed that Noctiluca was abundant (up to 28 cells l^?1) within mature upwelled waters. A high proportion (>80%) of fed Noctiluca cells (cells with prey in their vacuoles) was observed in the mature upwelled waters indicating that the observed increase in abundance of Noctiluca was associated with increased feeding activity. The absolute abundance of Noctiluca in upwelled waters was, however, found to vary from one upwelling location to another and between seasons. In particular, highest abundances of Noctiluca were recorded south of 31.5°S, where the East Australian Current (EAC) characteristically separates from the coast. The high abundances partly arise from southward advection and retention of the Noctiluca cells, and partly from upwelling inshore of the separated EAC driven by cross-shelf boundary layer fluxes. The temperature of the EAC was also found to influence absolute abundances. Surface water temperatures during our summer cruise were anomalously high due to a strong La Niña phase, and up to 4°C warmer than during our spring cruise. We found that the warmer surface water temperatures were associated with relatively lower average abundances of Noctiluca in the near shore zone.     

Spatial ecology of the mulgara in arid Australia: impact of fire history on home range size and burrow use

Knowledge about the spatial ecology of small mammals in relation to fire history in arid zones in general and Australia in particular is limited. Here, we report data on the spatial ecology of the brush-tailed mulgara Dasycercus blythi in the hummock grasslands of Ulu r u – Kata Tju t a National Park during winter 2006, the beginning of the breeding season for this species. About 73% of the study area had been burnt in 2002 and spinifex cover was sparse. Mulgaras Marsupialia: Dasyuridae (six males and three females) were implanted with radio-transmitters and monitored daily for between 6 and 55 days. All mulgaras appeared to use defined home ranges, which overlapped extensively with those of several neighbours. Spatial overlap occurred between as well as within sexes. On average, males (25.5 ha) occupied significantly larger home ranges than females (10.8 ha). Mulgaras used a number of burrows within home ranges and several were used by more than one individual. Moreover, occasionally, two individuals used the same burrow simultaneously. Home ranges and burrows encompassed both mature spinifex Triodia basedowii and open regrowth areas and mulgaras did not exhibit a significant preference for either habitat type. However, three males were killed by introduced-predators and they all lived predominantly in the open regrowth area. We conclude that mulgaras do not select the dense cover of mature spinifex habitat, and might be subjected to increased risk from introduced predators, especially following fire.     

Life history of the cownose ray, <Emphasis Type="Italic">Rhinoptera bonasus</Emphasis>, in the northern Gulf of Mexico,with comments on geographic variability in life history traits

Synopsis We determined age and growth, size at maturity, and fecundity for cownose rays, Rhinoptera bonasus, collected from the northern Gulf of Mexico. Vertebral age estimates ranged from 0+ to 18+ years for females and 0+ to 16+ years for males. Annual deposition of growth increments was verified with marginal increment analysis. Likelihood ratio tests indicated that the growth of the cownose ray was best described by a combined sexes Gompertz model. Median size at 50% maturity was determined to be 642 mm DW for males and 653 mm DW for females, or 4–5 years of age. Median pup size-at-birth was estimated to be 350 mm DW, with a gestation period of 11–12 months. In all cases, gravid females contained only one pup. Statistically significant differences were detected between growth curves for the Gulf of Mexico and the western Atlantic Ocean. Cownose rays in the Gulf of Mexico had lower estimates of DW_∞ and K, and a higher theoretical longevity than their conspecifics in the western Atlantic Ocean. Cownose rays in the Gulf of Mexico also attain maturity at a smaller size and earlier age than their counterparts in the western Atlantic Ocean.     

Effects of reproductive timing and colony size on the survival, offspring colony size and drone production in the honey bee (Apis mellifera)

ABSTRACT. 1. The effects of colony size and time of reproduction on the survival and size of offspring colonies and on drone production were examined for honey bees, Apis mellifera L. Drone and worker production and survival of parental and offspring colonies were monitored following swarming. Also, the temporal patterns of drone emergence and availability of unmated queens were examined.
2. Colony size at swarming was positively correlated with the number of workers invested in offspring colonies and the number of queens produced. However, colony size at swarming was not correlated with the number of offspring colonies produced.
3. Swarm size was positively correlated with drone and worker production after swarms were hived. Worker production of hived swarms was positively correlated with colony survival. Offspring queens which inherited a parental nest survived longer than queens in either primary swarms or afterswarms, presumably due to the advantage of inheriting a nest.
4. Drone emergence peaked just prior to swarming, the time when unmated queens were available. High drone production by colonies initiated by swarms probably reflected an attempt to reproduce prior to winter. The probabilities of a second swarming cycle within the same year and of surviving the winter were low for colonies initiated from swarms.     

Distribution,relative abundance and size composition of the threatened serranid Epinephelus daemelii in New South Wales,Australia

The aim of this study was to undertake baseline surveys on the distribution, relative abundance and total lengths (L_T) of a threatened epinephelid species, black cod Epinephelus daemelii, in New South Wales (NSW), Australia, their westernmost distribution. Diving surveys at 83 sites where E. daemelii were expected to occur were undertaken from 2009 to 2011 using 45 min roving diver counts. Sites were spread through northern NSW, including Lord Howe Island (LHI). Individual fish were measured using stereo‐video, enabling accurate length measurement. Surveys were repeated at a sub‐set of sites to assess temporal variation across days, seasons and years. A total of 117 E. daemelii were recorded during baseline surveys, occurring at 42% of the surveyed sites. Across all surveys, the highest numbers recorded (14–18 individuals at a site) were at the outer Solitary Islands and Fish Rock (Smoky Cape). Fewer E. daemelii were found southwards, but two sites in the Port Stephens–Great Lakes Marine Park had consistent numbers (three to six) over four annual surveys. Only 12 E. daemelii were recorded from eight of the 18 sites at LHI. The numbers observed at re‐surveyed sites were generally stable over years. There were latitudinal and cross‐shelf differences in L_T. Individuals in the north were found to be significantly larger than those further south, and fish offshore were significantly larger than those inshore. The largest measured fish was 135 cm, smaller than the maximum L_T(c. 170 cm) recorded for this species. The smallest fish was 26 cm. Overall, it is considered that the abundance of E. daemelii is low compared to anecdotal data even though they have been protected for c. 30 years in NSW. These findings provide an essential benchmark to assess ongoing status and response to protective management.     

Distribution and abundance of marine wood borers on the west coast of Peninsular Malaysia

Twenty one species of marine wood borers were recorded in this study. There are seventeen species of bivalves of which sixteen are from the family Teredinidae and one from the family Pholadidae. The crustaceans comprised the family Sphaeromatidae with three species and the family Limnoriidae with one species. Seven of the fourteen known genera of the teredinids were recorded. The bivalve wood borers were widely distributed in the local mangroves. Martesia striata was the most abundant wood borer at the Degaussing Range jetty, Lumut. Lyrodus pedicellatus was the most abundant shipworm in wooden panels. Shipworms were abundant on the subtidal panels where the genus Bankia, was most common while M. striata was abundant on the intertidal panels. M. striata numbers were higher on the top surfaces as compared to the under surfaces of wooden panels.     

崇明东滩湿地自然植被演替过程中储碳及固碳功能变化

采用实地调查与实验室测定相结合的方法,研究了崇明东滩湿地植被演替过程中储碳、固碳功能的变化.结果表明：不同演替阶段的湿地植被的现存碳储量及其分配格局特征存在较大差异.先锋物种海三棱藨草的现存碳储量仅占芦苇现存碳储量的13%;地下根茎为芦苇现存碳储量的主要场所,而地上部分是海三棱藨草碳储量的主要场所.处于潮滩湿地演替中后期的芦苇群落比处在生态演替早期的海三棱藨草群落具有更强的固碳能力,芦苇群落和海三棱藨草群落的年固碳能力分别为(1.63±0.39) kg·m^-2和(0.63±0.28) kg·m^-2,说明随着海三棱藨草群落向芦苇群落演替,其固碳能力不断增强.     

Reproductive parameters of rhinobatid and urolophid batoids taken as by‐catch in the Queensland (Australia) east coast otter‐trawl fishery

Reproductive variables are provided for batoids regularly taken as by‐catch in the east coast otter‐trawl fishery on the inner‐mid continental shelf off the south‐east and central coasts of Queensland, Australia. Total length at maturity (L_T50 and 95% c.i .) for the eastern shovelnose ray Aptychotrema rostrata was 639·5 mm (617·6–663·4 mm) for females and 597·3 mm (551·4–648·6 mm) for males. Litter size (n = 9) ranged from nine to 20 (mean ± s.e. = 15·1 ± 1·2). This species exhibited a positive litter size–maternal size relationship. Disc width at maturity (W_D50 and 95% c.i .) for the common stingaree Trygonoptera testacea was 162·7 mm (155·8–168·5 mm) for females and 145·9 mm (140·2–150·2 mm) for males. Gravid T. testacea (n = 6) each carried a single egg in the one functional (left) uterus. Disc width at maturity (W_D50 and 95% c.i .) for the Kapala stingaree Urolophus kapalensis was 153·7 mm (145·1–160·4 mm) for females and 155·2 mm (149·1–159·1 mm) for males. Gravid U. kapalensis (n = 16) each carried a single egg or embryo in the one functional (left) uterus. A single female yellowback stingaree Urolophus sufflavus carried an embryo in each uterus. A global review of the litter sizes of shovelnose rays (Rhinobatidae) and stingarees (Urolophidae) is provided.     

Microbial diversity in coastal sediments during pre- and post-tsunami periods in the south east coast of India

Sediment samples were collected from 12 beaches affected by the 2004 Asian Tsunami in the south-east coast of India between Vanagiri and Nagoor. The objective of the present study is to delineate the microbial diversity in pre- and post-tsunami disaster coastal sediments. The collected marine sediments indicate that the overall microbial diversity is higher in the pre-tsunami sediments. The increase in pathogenic bacteria and fungal species after the tsunami is obscured due to inundation and backwashing of seawater along the coast. The reduction of other microbial diversity after the tsunami is attributed that the coastal and shelf sediments play an important role in the demineralization of organic matter, which supports the growth of microbes. The continuous exchange of ocean water and backwashing of coastal sediments by the tsunami wave probably reduced the pathogenic bacterial diversity in the sediments.