Refine
Document Type
- Article (2) (remove)
Language
- English (2)
Has Fulltext
- yes (2)
Is part of the Bibliography
- no (2)
Keywords
- fish (2) (remove)
Prioritization of introduction pathways is seen as an important component of the management of biological invasions. We address whether established alien plants, mammals, freshwater fish and terrestrial invertebrates with known ecological impacts are associated with particular introduction pathways (release, escape, contaminant, stowaway, corridor and unaided). We used the information from the European alien species database DAISIE (www.europe-aliens.org) supplemented by the EASIN catalogue (European Alien Species Information Network), and expert knowledge. Plants introduced by the pathways release, corridor and unaided were disproportionately more likely to have ecological impacts than those introduced as contaminants. In contrast, impacts were not associated with particular introduction pathways for invertebrates, mammals or fish. Thus, while for plants management strategies should be targeted towards the appropriate pathways, for animals, management should focus on reducing the total number of taxa introduced, targeting those pathways responsible for high numbers of introductions. However, regardless of taxonomic group, having multiple introduction pathways increases the likelihood of the species having an ecological impact. This may simply reflect that species introduced by multiple pathways have high propagule pressure and so have a high probability of establishment. Clearly, patterns of invasion are determined by many interacting factors and management strategies should reflect this complexity.
Evidence from archaeological fish bone assemblages from the southern North Sea region of Europe is used to illuminate fishing, fish consumption and fish trade from the 1st to the 16th century AD. The fish species represented in the material indicate a very strong influence from the local fish fauna at almost all sites. The species and size of the fish indicate that several fishing methods have been employed throughout the period studied, including nets, hooks and weirs. A chronological development in fishing, for example, a tendency towards more sea-going fishing, is reflected in the fish bone assemblages in some countlres. Evidence from fishing in the Baltic region from the 5th century BC to the 16th century AD is included in the discussion. Indications of fish trade include bones of exotic species (for instance, matinc species at inland sites) and an unbalanced representation of skeletal clements (trade with decapitated stockfish or gillless hering). Of particular interest are assemblages which indicate a fish industry, for instance, large-scale processing (removal of gills) of herring in 13th century Denmark.