The effects of metomidate anaesthesia on levels of plasma cortisol, glucose, haematocrit and chloride in Atlantic salmon (1 + ) (Salmo salar L.), after a 2-h transport and during a 48-h recovery period were investigated. The use of metomidate anaesthesia during transport led to a reduced release of cortisol and signi®cantly lower levels of plasma cortisol after a 48-h recovery period. Plasma glucose did not return to basal level after a 48-h recovery period, indicating that even longer recovery may be needed for the ®sh to return to a pre-stress state. The results show that metomidate anaesthesia combined with a recovery period lessens the stress burden imposed by hauling and transport.
Signal crayfish, as an invasive alien species in Europe, have caused impacts on aquatic communities and losses of native crayfish. Eradication of recently established populations may be possible in small ponds (<2.5 ha) and short lengths of small watercourses using a nonselective biocide. Between 2004 and 2012, a total of 13 sites in the U.K. were assessed for suitability. Six were treated with natural pyrethrum and crayfish were successfully eradicated from three. In Norway, five sites were assessed and two sites were treated with a synthetic pyrethroid, cypermethrin, both successfully. In Sweden, three sites were treated with another synthetic pyrethroid, deltamethrin, all successfully. Defining the likely extent of population was critical in determining the feasibility of treatment, as well as the ability to treat the whole population effectively. Important constraints on projects included site size, habitat complexity, environmental risks, cooperation of landowners and funding availability. Successful projects were manageably small, had good project leadership, had cooperation from stakeholders, had access to resources and were carried out within one to three years. Factors influencing success included treating beyond the likely maximum geographical extent of the population and taking care to dose the treated area thoroughly (open water, plus the banks, margins, inflows and outflows). Recommendations are given on assessing the feasibility of biocide treatments and project-planning.
Introduced alien species bring potential adverse impacts on biodiversity and ecosystem functions. International shipping is an important vector for such unintentional introductions in aquatic environments. Therefore, in addition to climate change and eutrophication, increasing international shipping may enhance the spread of alien species into areas which have not previously been considered prone to alien invasions. One example of such development might be the recent invasion of the moss animal Pectinatella magnifica into Finnish inland waters, which are generally considered to be hostile to alien species. We took advantage of observations made by the general public and recorded by environmental authorities to describe the invasion history of the species in Finland. The records of P. magnifica were almost exclusively from the Vuoksi watercourse, where the species was most likely introduced by international shipping ca 10-15 years ago. The species occurred mainly in the vicinity of ports of international shipping, but was also abundant in an area with only domestic cargo transport. Only one confirmed observation in Lake Kirkkojärvi was from outside the Vuoksi watercourse. Most colonies were found attached to landing stages or submerged, relatively rigid water plants, and the species seemed to avoid less rigid water plants, such as water lilies. Once established, the species may spread by vectors such as recreational boating or water birds and fish. The species poses some risks to the ecosystem, including a risk to farmed and wild salmonid fish by serving as a potential host for the myxozoan endoparasite Tetracapsuloides bryosalmonae, the causative agent for proliferative kidney disease (PKD), known to be detrimental for salmonid fish.
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