Rob Fryer | PubMed Health

PubMed2002

Developing effective environmental indicators--does a new dog need old tricks?

Environmental indicators are being increasingly used to emphasise the relevance of monitoring. However, indicators must also be effective. In particular, they must be able to answer management questions, be accessible to the target audience and be sufficiently precise. Here, we use a time series of mercury levels in plaice from Liverpool Bay to illustrate how specific management questions can be formulated, answered, and the precision of these answers assessed. We also show how a programme design can incorporate a series of management questions that are likely to arise over time in response to observed changes in a time series.

Animals↗

PubMed2002

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.

Animals↗