Uptake and effects of the cypermethrin-containing sea lice treatment Excis in the marine mussel,Mytilus edulis

Wild and farmed mussels, Mytilus edulis, coexist with salmon farms in Scottish sea lochs. A synthetic pyrethroid, cypermethrin, is licensed for use on fish farms to control sea lice infestations as a formulation called Excis. In this study, uptake of cypermethrin from Excis exposure is investigated through the use of gas chromatography with mass-spectrometry. The effects of Excis on mussels are also examined by measuring the neutral red retention time of lysosomes, aerial survival and shell closure. The isomeric ratios of cis:trans cypermethrin measured in mussels are around 80:20; a marked increase from 40:60 to which the mussels were exposed. This is most likely due to preferential metabolism of trans-isomers, as the same response is seen in vertebrates. There is a pronounced behavioural effect of shell closure, where mussels exposed to 1000 microg/l cypermethrin shut their shells within an hour of exposure. Arguments are presented for this effect being either a voluntary response on recognition of cypermethrin, or an effect arising from an involuntary action of cypermethrin on the adductor muscle. Even at 1000 microg/l cypermethrin, neutral red retention time and aerial survival are not affected. The data suggest that the responses of mussels shown here are unlikely to occur in the field, even at the concentrations of cypermethrin used in fish cages, for the treatment of sea lice.     

Development of an integrated environmental data base

The ability to access information for use in decision making is a well-recognized need within the context of management sciences. A similar need exists in order to make effective technical decisions pertaining to environmental resource management. Data bases are the principle vehicle by which scientists, engineers, and resource managers store and access environmental information. An integrated data-base mechanism is essential in order for federal agencies to manage programs such as enforcement of the Canadian Environmental Protection Act (CEPA), state of the environment (SOE) reporting, and the environmental assessment and review process (EARP). A data-base structure and data dissemination mechanism under current development within Environment Canada, Conservation and Protection, Atlantic Region, is presented along with some of its operational benefits and constraints.     

Managing the metropolitan environment: the challenge for European cities

Traditional approaches to metropolitan management have placed stress upon the achievement of physical and economic growth. In recent years attention has turned to environmental concerns and the achievement of sustainable urban development. It is important to define the objectives for the sustainable development of cities and to identify the principles upon which such development can be based.     

Project appraisal and planning for overdeveloped countries: II. Shadow pricing under uncertainty

In the uncertainty that surrounds the future availability of nonrenewable natural resources and the efficacy of technological advance, the economic costing of resources should be undertaken probabilistically. While optimistic assumptions entail little change from the costing procedures used in conventional cost-benefit analysis, even moderately pessimistic assumptions lead to a much increased cost for nonrenewable resources. These lead in turn to a reappraisal of the value of investment and of the cost ascribed to other factors of production. Even when optimistic assumptions are deemed the more plausible, a utility-maximizing evaluation may still give more emphasis to pessimism.     

Socially cooperative choices: An approach to achieving resource sustainability in the coastal zone

Achieving resource sustainability, particularly in the coastal zone, is complicated by a variety of interdependencies and trade-offs between economic, social, and ecological variables. Although trade-offs between each of these variables are important, this paper emphasizes the social components of resource management. In this regard a distinction is made between individual and cooperative choices. Individual choices frequently are made from a shortterm, self-interested perspective, whereas cooperative choices are made from a long-term, community and resource-sustainability perspective. Typically, when presented with a spectrum of resource management decisions, individuals have a tendency to act in a self-interested manner. Thus, cooperative benefits, such as reduced conflict and improved resource certainty, are not realized. An overview of selected aspects of social dilemma theory suggests that socially cooperative choice outcomes are attainable in coastal zone management by integrating structural and behavioral solutions in resource use decision making. Three barriers to successful integration of structural and behavioral solutions are identified as self-interest, mistrust, and variable perceptions of resource amenities. Examples from coastal zone management indicate that these barriers may be overcome using approaches such as scopereduction, co-management, community education, and local participation. The paper also provides comment on the potential benefits of integrating structural and behavioral solutions in international coastal zone management efforts.     

Do we have to incorporate ecological interactions in the sensitivity assessment of ecosystems? An examination of a theoretical assumption underlying species sensitivity distribution models

Species sensitivity distributions (SSDs) are statistical distributions which extrapolate single-species toxicity test results to ecosystem effects. This SSD approach assumes that ecological interactions between populations, such as grazing and competition, do not influence the sensitivity of ecosystems. The validity of this assumption in a simple freshwater pelagic ecosystem was tested using ecosystem modelling. For each of a 1000 hypothetical toxicants, a lognormal SSD was fitted to chronic single-species EC10s of the species present. As such, these distributions did not account for ecological interactions and were therefore termed 'conventional SSDs' (cSSDs). Next, sensitivity distributions that did take into account ecological interactions were constructed (eco-SSD) for the same 1000 toxicants, using an ecosystem model. For 254 of the 1000 hypothetical toxicants, mean and/or variance of the cSSD were significantly higher than mean and/or variance of the eco-SSD, as such rejecting the general validity of the tested assumption. A classification tree approach indicated that especially toxicants which directly affect phytoplankton (i.e. herbicides) may have a higher mean for cSSD than for eco-SSD. Conversely, means of eco-SSD and cSSD tend to be equal for toxicants directly affecting zooplankton and fish, e.g. insecticides. For the 254 hypothetical toxicants for which the tested assumption was false, a predicted no effect concentration (PNEC) calculated as the lowest single-species EC10 divided by an application factor of 10 was on average a factor 10 lower than the corresponding ecosystem-NOEC calculated by the ecosystem model.     

Climate change and coastal vulnerability assessment: scenarios for integrated assessment

Coastal vulnerability assessments still focus mainly on sea-level rise, with less attention paid to other dimensions of climate change. The influence of non-climatic environmental change or socio-economic change is even less considered, and is often completely ignored. Given that the profound coastal changes of the twentieth century are likely to continue through the twenty-first century, this is a major omission, which may overstate the importance of climate change, and may also miss significant interactions of climate change with other non-climate drivers. To better support climate and coastal management policy development, more integrated assessments of climatic change in coastal areas are required, including the significant non-climatic changes. This paper explores the development of relevant climate and non-climate drivers, with an emphasis on the non-climate drivers. While these issues are applicable within any scenario framework, our ideas are illustrated using the widely used SRES scenarios, with both impacts and adaptation being considered. Importantly, scenario development is a process, and the assumptions that are made about future conditions concerning the coast need to be explicit, transparent and open to scientific debate concerning their realism and likelihood. These issues are generic across other sectors.

Estimates of sex- and age-class-specific survival probabilities for a southern Great Barrier Reef green sea turtle population

Sex- and age-class-specific survival probabilities of a southern Great Barrier Reef green sea turtle population were estimated using a capture–mark–recapture (CMR) study and a Cormack–Jolly–Seber (CJS) modelling approach. The CMR history profiles for 954 individual turtles tagged over a 9-year period (1984–1992) were classified into three age classes (adult, subadult, juvenile) based on somatic growth and reproductive traits. Reduced-parameter CJS models, accounting for constant survival and time-specific recapture, fitted best for all age classes. There were no significant sex-specific differences in either survival or recapture probabilities for any age class. Mean annual adult survival was estimated at 0.9482 (95% CI: 0.92–0.98) and was significantly higher than survival for either subadults or juveniles. Mean annual subadult survival was 0.8474 (95% CI: 0.79–0.91), which was not significantly different from mean annual juvenile survival estimated at 0.8804 (95% CI: 0.84–0.93). The time-specific adult recapture probabilities were a function of sampling effort but this was not the case for either juveniles or subadults. The sampling effort effect was accounted for explicitly in the estimation of adult survival and recapture probabilities. These are the first comprehensive sex- and age-class-specific survival and recapture probability estimates for a green sea turtle population derived from a long-term CMR program.Communicated by M.S. Johnson, Crawley     

Interaction between peat, humic acid and aqueous metal ions

Analysis of peat samples from four regions of the British Isles indicates that the concentrations of Al, Pb and common transition metals tend, as expected, to be higher in regions subject to industrial pollution, but that the concentrations of the nontransition metals Na, K, Mg, Ca and Zn tend to be higher in regions remote from industrial pollution. Humic acids were extracted from the most polluted and least polluted of the peat samples and some characteristics of these acids were compared with those of two commercial acids. Values for stability constants of complexes formed between humic acids extracted from peat and Cu²⁺, Zn²⁺ or Pb²⁺ have been obtained by an ionexchange equilibrium method. Of the three metal ions examined, Pb²⁺ was found to form the most stable humic acid complexes, followed by Cu²⁺: this order agrees with the findings of Irving and Williams and of Bunzl. Implications to the binding of actinide and other heavy metal ions in aqueous humic acid are discussed.     

Evidence of a fall in cord blood lead levels in South Wales 1984–85

A monitoring scheme for blood lead was based on cord blood samples and maternal blood samples taken in Swansea, South Wales. A fall of around 20% during 1984–85 is described. During this period there was virtually no change in petrol sales in the area and no overall change in air lead levels. Air lead showed large seasonal changes but these were not reflected in blood lead. Water lead levels gave no evidence of changes of any importance during the period of monitoring. These results suggest that petrol lead was at most a minor contributor to blood lead.