The sabellid, Terebrasabella heterouncinata, is a small (<5 mm) intratubular brooder that lives in burrows within the hosts shell matrix. It is a semi-continuous breeder and despite producing small numbers of large eggs, infestation by this animal has reached epidemic proportions on local abalone farms. The present study compared the morphometrics and reproductive characteristics of worms from farmed and wild abalone, in the Walker Bay area of the south Western Cape Province of South Africa, to gain insights into why this animal has become so successful under aquaculture conditions. The farms designated farm A and farm B each had one on-farm site, and two wild sites, while farm C had two on-farm sites and two wild sites. The wild sites were natural abalone habitats located within 2.5 km of the farms. Our results conclusively showed that environmental conditions prevalent on the farms enhanced the reproductive success of these worms relative to that observed in its natural environment. At farms B and C, worms occurred in significantly higher densities at the on-farm sites than in the corresponding wild samples, but at farm A, density was equally low at the three sites. At all three farms, a greater proportion of the population was reproductively active in the on-farm samples than in the wild samples. Worms on farmed abalone had a higher instantaneous fecundity, brooded more clutches simultaneously and were larger than their conspecifics from the wild. There was a positive correlation between adult size and brood size and the number of clutches brooded simultaneously. Within the three on-farm sites there was a negative correlation between egg volume and brood size, indicating a trade-off between these traits. However, such a trade-off was not apparent between sites, with brood size being higher at the on-farm sites than at the wild sites, irrespective of egg size. This suggests that the stable nutrient-enriched environment on the farm led to an increase in fecundity without compromising the size (and implicitly the quality) of the eggs. Worm density did not have a significant effect on body size or any other reproductive traits at most sites, and the density of T. heterouncinata was unaffected by the density of other shell-infesting polychaetes. The results suggest that the farm environment has selected for larger, more fecund worms that breed rapidly with high recruitment success as a consequence of abundant nutrients, high host density, habitat stability and a possible lack of predation and interspecific competition.Communicated by J.P. Thorpe, Port Erin 相似文献
Background: State laws regarding child passenger protection vary substantially.
Objectives: The objective of this study was to develop a scoring system to rate child passenger safety laws relative to best practice recommendations for each age of child.
Methods: State child passenger safety and seat belt laws were retrieved from the LexisNexis database for the years 2002–2015. Text of the laws was reviewed and compared to current best practice recommendations for child occupant protection for each age of child.
Results: A 0–4 scale was developed to rate the strength of the state law relative to current best practice recommendations. A rating of 3 corresponds to a law that requires a restraint that is sufficient to meet best practice, and a rating of 4 is given to a law that specifies several options that would meet best practice. Scores of 0, 1, or 2 are given to laws requiring less than best practice to different degrees. The same scale is used for each age of child despite different restraint recommendations for each age. Legislation that receives a score of 3 requires rear-facing child restraints for children under age 2, forward-facing harnessed child restraints for children aged 2 to 4, booster seats for children 5 to 10, and primary enforcement of seat belt use in all positions for children aged 11–13. Legislation requiring use of a “child restraint system according to instructions” would receive a score of 1 for children under age 2 and a 2 for children aged 2–4 because it would allow premature use of a booster for children weighing more than 13.6 kg (30 lb).
Conclusions: The scoring system developed in this study can be used in mathematical models to predict how child passenger safety legislation affects child restraint practices. 相似文献
Adaptive management (AM) is a rigorous approach to implementing, monitoring, and evaluating actions, so as to learn and adjust those actions. Existing AM projects are at risk from climate change, and current AM guidance does not provide adequate methods to deal with this risk. Climate change adaptation (CCA) is an approach to plan and implement actions to reduce risks from climate variability and climate change, and to exploit beneficial opportunities. AM projects could be made more resilient to extreme climate events by applying the principles and procedures of CCA. To test this idea, we analyze the effects of extreme climatic events on five existing AM projects focused on ecosystem restoration and species recovery, in the Russian, Trinity, Okanagan, Platte, and Missouri River Basins. We examine these five case studies together to generate insights on how integrating CCA principles and practices into their design and implementation could improve their sustainability, despite significant technical and institutional challenges, particularly at larger scales. Although climate change brings substantial risks to AM projects, it may also provide opportunities, including creating new habitats, increasing the ability to quickly test flow‐habitat hypotheses, stimulating improvements in watershed management and water conservation, expanding the use of real‐time tools for flow management, and catalyzing creative application of CCA principles and procedures. 相似文献
Regulators seem to currently be focusing on green remediation and not sustainable remediation. How can the industry change this perception so that a more holistic approach is followed? 相似文献
Mainstreaming climate change adaptation (CCA) into plans and programs is still a new approach in adaptation and thus there is limited information on how to operationalize it on-ground. This paper addresses this gap by investigating the challenges in mainstreaming CCA into the local land use plans in the province of Albay, Philippines. Specifically, this paper developed 20 quantitative “mainstreaming indicators” to assess the state-of-play and the challenges for local mainstreaming. These indicators were classified under three groupings, namely, the information, institutional, and resource capacities of systems. Qualitative analysis of the indicator scores suggested that developing the institutional capacities of local governments is crucial in the local mainstreaming process. Likewise, the results highlighted the “institutional issues” indicator as the primary barrier in operationalizing the approach. These institutional issues are: fragmented laws and regulations; overlapping policy requirements; and the lack of guidelines for mainstreaming CCA into the local land use plans. Meanwhile, the “leadership” indicator, as signified by a climate change champion in Albay, was evaluated as an opportunity for local mainstreaming. The champion effectively led the CCA efforts because the existing institutional mechanisms supported the champion’s capacity to influence the behavior of people and produce collective action towards CCA. 相似文献
Large marine protected areas (MPAs) of unprecedented size have recently been established across the global oceans, yet their ability to meet conservation objectives is debated. Key areas of debate include uncertainty over nations’ abilities to enforce fishing bans across vast, remote regions and the intensity of human impacts before and after MPA implementation. We used a recently developed vessel tracking data set (produced using Automatic Identification System detections) to quantify the response of industrial fishing fleets to 5 of the largest MPAs established in the Pacific Ocean since 2013. After their implementation, all 5 MPAs successfully kept industrial fishing effort exceptionally low. Detected fishing effort was already low in 4 of the 5 large MPAs prior to MPA implementation, particularly relative to nearby regions that did not receive formal protection. Our results suggest that these large MPAs may present major conservation opportunities in relatively intact ecosystems with low immediate impact to industrial fisheries, but the large MPAs we considered often did not significantly reduce fishing effort because baseline fishing was typically low. It is yet to be determined how large MPAs may shape global ocean conservation in the future if the footprint of human influence continues to expand. Continued improvement in understanding of how large MPAs interact with industrial fisheries is a crucial step toward defining their role in global ocean management. 相似文献
Cathode ray tube (CRT) glass is considered a hazardous material due to its lead toxicity. In addition, current disposal practices are being phased out due to their adverse environmental impacts. In this project, CRT glass was used as a fine aggregate replacement in concrete. Life-cycle material characterization was conducted by evaluating the durability and strength of the CRT-Concrete. Leaching tests were also conducted to investigate whether the material meets drinking water limits for Pb. Test results show that the plastic state of the CRT-Concrete was affected by the angularity of the glass particles. Moreover, the compressive strength of CRT-Concrete met and exceeded that of the control specimen. However, CRT-Concrete was susceptible to expansive alkali-silica reactions when more than 10% CRT replacement was used. Environmental leaching results show that lead concentrations from CRT-Concrete are below the drinking water limits depending on the CRT volume replacement and if biopolymers are used. 相似文献