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Sampling Programs (sampling + program)
Selected AbstractsPopulation biology and status of exploitation of introduced garfish Belone belone euxini (Günther, 1866) in the Black SeaJOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2006O. Samsun Summary The garfish Belone belone euxini (Günther, 1866) is a commercially important pelagic fish species in Sinop artisanal fishery, which is showing a decreasing trend in catch results. As a basis for fisheries management a sampling program was carried out between October 2000 and September 2001 along the Turkish coast of the Black Sea, to study the population structure, growth, and reproduction cycle of garfish in the area, and to achieve a rough estimate of exploitation. The length,weight relationship and von Bertalanffy growth parameters were estimated as W = 0.00076 L3.137, L, = 74.64 cm, K = 0.13 year,1, to = ,3.67, respectively. First sexual maturity was estimated at age 2 and at a total length of 38.8 cm for females. The spawning period was from May to September. The total fecundity,length relationship was estimated as F = 0.0041 L4.1086 (r2 = 0.92). Mortality rates were Z = 1.24 year,1, M = 0.23 year,1and F = 1.01 year,1 for total, natural, and fishing mortality, respectively. The exploitation ratio E = 0.81 indicates that the population is heavily exploited. [source] Wildlife habitat strips and native forest ground-active beetle assemblages in plantation nodes in northeast TasmaniaAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 4 2005Simon Grove Abstract, In Tasmania, plantation establishment is often concentrated in ,nodes', a practice that can result in a high degree of fragmentation of remaining native forest in these areas. In this study we examined the sensitivity of ground-active beetles to the effects of conversion of native forest to plantation in which remaining native forest is largely confined to narrow wildlife habitat strips. At five damp sclerophyll forest sites in northeast Tasmania, pitfall sampling was carried out along the middle axis of a wildlife habitat strip, in the young plantation surrounding the strip, and at three distances in from the edge of nearby continuous native forest. The study documented a rich fauna, particularly for carabids. Species composition varied among sites, emphasising the need for adequate regional reservation of native forest at appropriate spatial scales. While plots in plantations and strips supported similar numbers of species as continuous native forest, they usually differed in assemblage composition. In general, assemblages in strips appeared to be intermediate in composition between those of continuous native forest and plantations. Significant differences corresponding to a progressive change in assemblage composition with distance into continuous native forest from its edge were detected for one, possibly two, sites. Plots in strips were generally more similar in assemblage composition to those near the edge of continuous native forest than to those towards its interior. Within the study area, strips may promote the survival of species that otherwise associate with the edges of continuous native forest, but they may provide less effective habitat for species that associate with native forest interiors. However, they still harbour many native forest species which are rare or absent in plantations. Although only based on a short-term sampling program, the study implies that future strips in Tasmanian damp sclerophyll forest could better benefit some forest interior species if prescriptions were to specify wider strips. However, a clearer conservation outcome might be to ensure the continuance of a sufficiently comprehensive, adequate and representative network of native forest formal reserves (in addition to wildlife habitat strips) containing damp sclerophyll forest. These should be large enough to cater for forest interior species, and dispersed at a spatial scale appropriate to the rate of species turnover found among ground-active beetle assemblages in these forests. [source] Ecological responses to altered flow regimes: a literature review to inform the science and management of environmental flowsFRESHWATER BIOLOGY, Issue 1 2010N. LEROY POFF Summary 1.,In an effort to develop quantitative relationships between various kinds of flow alteration and ecological responses, we reviewed 165 papers published over the last four decades, with a focus on more recent papers. Our aim was to determine if general relationships could be drawn from disparate case studies in the literature that might inform environmental flows science and management. 2.,For all 165 papers we characterised flow alteration in terms of magnitude, frequency, duration, timing and rate of change as reported by the individual studies. Ecological responses were characterised according to taxonomic identity (macroinvertebrates, fish, riparian vegetation) and type of response (abundance, diversity, demographic parameters). A ,qualitative' or narrative summary of the reported results strongly corroborated previous, less comprehensive, reviews by documenting strong and variable ecological responses to all types of flow alteration. Of the 165 papers, 152 (92%) reported decreased values for recorded ecological metrics in response to a variety of types of flow alteration, whereas 21 papers (13%) reported increased values. 3.,Fifty-five papers had information suitable for quantitative analysis of ecological response to flow alteration. Seventy per cent of these papers reported on alteration in flow magnitude, yielding a total of 65 data points suitable for analysis. The quantitative analysis provided some insight into the relative sensitivities of different ecological groups to alteration in flow magnitudes, but robust statistical relationships were not supported. Macroinvertebrates showed mixed responses to changes in flow magnitude, with abundance and diversity both increasing and decreasing in response to elevated flows and to reduced flows. Fish abundance, diversity and demographic rates consistently declined in response to both elevated and reduced flow magnitude. Riparian vegetation metrics both increased and decreased in response to reduced peak flows, with increases reflecting mostly enhanced non-woody vegetative cover or encroachment into the stream channel. 4.,Our analyses do not support the use of the existing global literature to develop general, transferable quantitative relationships between flow alteration and ecological response; however, they do support the inference that flow alteration is associated with ecological change and that the risk of ecological change increases with increasing magnitude of flow alteration. 5.,New sampling programs and analyses that target sites across well-defined gradients of flow alteration are needed to quantify ecological response and develop robust and general flow alteration,ecological response relationships. Similarly, the collection of pre- and post-alteration data for new water development programs would significantly add to our basic understanding of ecological responses to flow alteration. [source] Suspended sediment transport regime in a debris-flow gully on Vancouver Island, British ColumbiaHYDROLOGICAL PROCESSES, Issue 4 2005Craig J. Nistor Abstract In debris-flow-prone channels, normal fluvial sediment transport occurs (nearly exclusively in suspended mode) between episodic debris-flow events. Observations of suspended sediment transport through a winter season in a steepland gully in logged terrain revealed two event types. When flows exceeded a threshold of 270 l s,1, events yielded significant quantities of sediment and suspended sediment concentration increased with flow. Smaller events were strongly ,supply limited'; sediment concentration decreased as flow increased. Overall, there is no consistent correlation between runoff and sediment yield. Within the season, three subseasons were identified (demarcated by periods of freezing weather) within which a pattern of fine sediment replenishment and evacuation occurred. Finally, a signature of fine sediment mobilization and exhaustion was observed within individual events. Fine sediment transport occurred in discrete pulses within storm periods, most of the yield occurring within 5 to 15% of storm runoff duration, so that it is unlikely that scheduled sampling programs would identify significant transport. Significant events are, however, generally forecastable on the basis of regional heavy rainfall warnings, providing a basis for targeted observations. Radiative snowmelt events and rain-on-snow remain difficult to forecast, since the projection of temperatures from the nearest regular weather station yields variable results. Copyright © 2004 John Wiley & Sons, Ltd. [source] Recall event timing: Measures of managerial performance in U.S. meat and poultry plantsAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 3 2005Ratapol Teratanavat This study investigates the performance of meat and poultry plant managers in discovering and responding effectively to food safety problems that lead to product recalls. Timing is used as a performance measure of managers' response to recalls of food, using survival distributions of times between production and recall, and recall case duration. The objectives are to understand how these time periods vary across plants and to determine factors explaining such variability. Survival distributions are estimated using the Kaplan-Meier and life table methods. Subgroups of the population are compared using plots of the estimated survival functions and statistically compared using log-rank and Wilcoxon tests. Managers at large plants, in multi-plant firms, and at plants with prior recall experience do not perform better. Cox regressions indicate that government agency sampling programs enhanced the speed of discovery, and that national distribution networks contributed to the risk that cases remained open for a longer period. [EconLit citations: D210, Q180.] © 2005 Wiley Periodicals, Inc. Agribusiness 21: 351,373, 2005. [source] | ||||||||||