Implications of life-history strategies for a new wrasse fishery

The variety of life-history patterns exhibited by the five species of wrasse common in Northern Europe are reviewed. The two larger wrasse species, the ballan, Labrus bergylta Ascanius, and cuckoo, Labrus mixtus (L.), are exploited through sport angling. The three smaller species, the corkwing, Symphodus (Crenilabrus) melops (L.), rock cook, Centrolabrus exoletus (L.) and goldsinny, Ctenolabrus rupestris (L.), are being exploited by a new fishery for use as parasite cleaners of farmed salmon.
The nature of salmon farming limits the wrasse fishery to a minimum size, restricted areas and the warmer months of the year. The fishery may be expected to alter population structure through selective removal of larger fish. Removal of dominant territorial males may affect social structures and removal of nest-guarding males would reduce egg survival. Quantitative models incorporating stock size and fishery requirements are now required.     

Statistical assessment of population variability: a methodological approach

We have implemented a multivariate statistical methodology to assess the degree and pattern of cranial variability in skeletal samples. Specifically, the method is designed to test whether variability in a skeletal sample exceeds "normal within-group variability" defined in the present instance as variability present among crania from a cemetery associated with a village. It involves comparing a covariance matrix derived from a sample of unknown composition to one representing "normal within-group variability." The method has been applied to two Plains Indian craniometric samples. The Leavenworth site (39CO9) represents the remnants of previously autonomous Arikara Indian villages devastated by epidemic diseases in the late 1700s. The Bad River 2 Phase is an archaeological designation grouping together closely related sites in the Bad-Cheyenne region of South Dakota dating from 1740-1795 AD. We were able to show substantial heterogeneity among crania from Leavenworth. District burial areas at Leavenworth account for some of the heterogeneity, supporting the notion that they represent an attempt to maintain former social distinctions. We were unable to differentiate among sites within the Bad River 2 Phase, suggesting that it is a valid biological unit.     

Intra- and intraspecific variation of Juniperus virginiana and J. scopulorum seedling based on volatile oil composition

Comparisons of volatile oil constituents were made among samples of juvenile foliage collected from 78 Juniperus virginiana and 28 J. scopulorum seedling sources growing in a “common garden” environment. A canonical variate analysis, a principal coordinates analysis and hybrid distance diagrams of 30 chemical characters indicate both taxa are good species and that they exhibit clinical patterns in the Great Plains. In addition, a possible evoluitonary link between present-day J. virginiana populations in southern Texas and ancient J. scopulorum populations is indicated.     

Size-frequency estimates of secondary production byMysis relicta in Lakes Michigan and Huron

Data from five Great Lakes studies ofMysis relicta populations were reanalyzed to calculate secondary production estimates using the size-frequency method. Production estimates (P) ranged from 0.25 to 3.2 g dry weight m^–2 yr^–1. Average annual biomass {xxB} and mean annual density (xxD) were 0.11–1.11 g dry weight/ m² and 25–434 animals/ m², respectively. P:{xxB} ratios varied only between 2.2 and 3.3. Maximum and minimum biomass values within a study varied by a factor of 519 for one study but by less than 17 for the others. Highest estimates of P, {xxB} and {xxD} were calculated for collections from a 50-m station in Lake Michigan despite the larger populations suspected to be present at greater depths sampled in the other studies. These conservative estimates provide a basis for scaling trophic interactions involvingM. relicta and emphasize findings by previous workers that night-time sampling with vertical net hauls is the best available technique for quantitative studies ofM. relicta populations in the Great Lakes.     

Effects of density on food utilization and surfacing behaviour in the obligatory air-breathing fish Channa striatus

Numbers of fungi were determined in water and sediment samples from a virgin salt-fresh water transect at North Point, James Bay. Fungal densities in the water samples showed an approximately linear increase from 28–70 CFU/100 ml, at the salt water extremity of the transect, to 13–16,000 CFU/100 ml at the freshwater extremity. Sediment fungal densities were also higher in the inland samples. There was no apparent difference between the numbers of fungi estimated using enumeration media prepared with distilled or saline water. Data are discussed in relation to the physical, chemical and organic status of the water, the nature of the surrounding vegetation and possible sources of the enumerated fungi.     

The populations of fish in tributaries of the River Eden on the Moor House National Nature Reserve,northern England

The population dynamics of trout (Salmo trutta L.) were studied in two high-altitude streams flowing westwards into the River Eden in northern England. The results from one (Knock Ore Gill), which is accessible to spawners from downstream, were compared with published data from an isolated population in a nearby stream which flows eastward into the River Tees. The Knock Ore Gill trout had a population density of 0.4–0.9 fish m^–2, a biomass of 12.4 g m^–2, annual production of 12–14 g m^–2 year^–1 and an instantaneous mortality rate of 0.97 year^–1. Comparable values from the Tees tributary were 0.2, 3.3, 2.3 and 0.66 respectively. The Knock Ore Gill population also contrasted with that of the Tees tributary in having reliable recruitment from year to year. These differences were related to differences in the chemistry and spate characteristics of the two streams and to the fact that immigrants from downstream were responsible for over 30% of the annual oviposition in Knock Ore Gill.     

人类新型β 3半乳糖基转移酶基因β 3GalT7 的克隆和鉴定

从人肺 cDNA 文库中克隆到人类β 3- 半乳糖基转移酶家族中的一个新成员β 3GalT7 (AY277592 , EC2.4.1.-) ,并对其进行了鉴定 . 该基因定位在人类染色体 19q13.2. 它包含一个 1 191 bp 的开放阅读框 (ORF). 编码的蛋白质包括一个信号肽和一个半乳糖基转移酶结构域,分子质量和等电点分别为 43.3 ku 和 8.37. 从原核表达中获得的融合蛋白的分子质量和预测相符 . RNA 印迹杂交显示β 3GalT7 在肺、喉和回肠组织中高表达,而在舌、乳房、子宫、睾丸等组织中表达较低 . 此外半定量 RT-PCR 显示β 3GalT7 在人类不同的肿瘤细胞中转录水平有明显差异 .     

Spring wetlands of the Great Artesian Basin,Queensland, Australia

The Great Artesian Basin is an aquifer system that underlies a large area of north-eastern Australia. The spring wetlands in the Great Artesian Basin are of conservation significance because they provide habitat for endemic species including fish, invertebrates and plants. Since European settlement massive quantities of water have been artificially extracted through bores, reducing spring-flows. Records of the springs of the Queensland section of the Great Artesian Basin (excluding Cape York Peninsula) were compiled from a range of historical sources. Most remaining active springs were visited and surveyed, the physical attributes of the springs described and their current status determined. Recharge springs occur in areas where the evidence suggests the basin is recharged by rainfall and 93% of the original 245 spring-groups in these areas are still active. Discharge springs occur in sections of the Basin down-gradient of the recharge areas and only 36% of the original 300 spring-groups in these areas have at least some springs that are still active. The capping of bores could provide a partial restoration of artesian pressure and enhance spring flows. Of the active spring-groups surveyed 26% have suffered major or total damage as a result of excavation of the wetlands. An emerging threat is the use of exotic grasses as ponded pastures, which have the ability to dominate the habitat of spring wetlands. The potential impacts of other threats including those associated with stock, exotic animals and fire are also discussed. Mitigating these threats requires a conservation strategy that seeks to protect remaining springs with high conservation values.