The threats posed by invasive freshwater crayfish species are one of the greatest concerns for freshwater ecologists, environmental managers, policy makers and local communities in the invaded regions.The invasive Australian redclaw crayfish Cherax quadricarinatus is rapidly spreading in southern Africa.Fishers in the Zambezi Basin have reported that crayfish affect their catch through partial consumption of fish caught on static gillnets.Owing to the immeasurable contributions of fishery to socioeconomic livelihoods in Africa, the catch losses that are due to crayfish are of concern.With this problem in Africa, it is imperative to continue researching on adaptive strategies to cope with the invasion.This study tested the effectiveness of "misdirection traps" to prevent fish spoilage and gear damage for gillnet catches by crayfish in Lake Kariba, Zimbabwe.The method involved placing baited traps along a gillnet to misdirect crayfish into the traps rather than fishing gear to prevent fish spoilage by scavenging.The misdirection traps significantly lowered the amount of catch spoilage.Gillnet damage by crayfish in general was minimal, although it was higher for gillnets without baited traps.The misdirection traps pose a pragmatic management initiative to reduce socioeconomic fishery costs from crayfish.We consider this method to be applicable in all the invaded regions where artisanal fishers are experiencing catch spoilage problems making a huge step towards preventing socioeconomic impacts associated with crayfish invasion.

Invasive ship rats (Rattus rattus) are a major threat to the native species and ecosystems of islands. We used 10 self-resetting traps (A24 rat and stoat traps, Goodnature Ltd., Wellington, NZ), along with existing single kill DOC200 traps at two devices per hectare on a 9.3 hectare island in New Zealand to reduce rat numbers and ideally achieve eradication. Each self-resetting trap was monitored with motion-activated cameras to analyse rat behaviour and A24 kill numbers were documented using Goodnature digital strike counters. The traps were checked on 10 occasions from August 2016 to October 2017. The videos documented initial high rat activity on the island, which reduced over time following initial trapping success. An immediately obvious neophobic response towards the A24 traps was not observed. Rats interacted with the A24 traps within hours after initial deployment and 60% of the traps were triggered in the first night. After three nights, all traps were triggered at least once. While rats interacted with the traps at all times of the year the number of observed trap-triggers was relatively low. High number of interactions resulted in high kill numbers in late spring when population size was increasing and seasonal food abundance had not yet reached its peak. A second peak was observed in late autumn when rat abundance was presumably high. Recruitment of nave individuals was a probable cause for high kill numbers during the breeding season. In winter, when rat abundance was presumably low, a few individuals were the likely cause for a high number of interactions while kill numbers were low. A knock-down (i.e. suppression from high to low abundance) of rats using both trap types was achieved in the first 100 days. However, kill numbers of A24s declined over time. After the initial suppression, the number of rats killed was insufficient to offset intrinsic population growth and reinvasion from the adjacent coast, thereby preventing eradication.

The European Commission has recently adopted its EU Biodiversity Strategy for 2030, which sets out an ambitious plan for reversing biodiversity loss, and preserving and restoring protected ecosystems. A central binding target is focused on enlarging the EU network of legally protected areas (Natura 2000, the largest global network of the world), and on maintaining or improving the conservation status of all vulnerable habitats and species included in them. Biological invasions are currently a major threat to Natura 2000, so fulfilling the objectives of the EU Biodiversity Strategy calls for stepping up the implementation and enforcement of the relevant legislation on the matter, which has been thoroughly revised over the last decade. We discuss here the regulatory aspects of legislation on invasive alien species (IAS) that need to be optimised to address the challenge posed by biological invasions to the Natura 2000 network in the light of the new EU Biodiversity Strategy. We highlight that, while the EU has designed a solid regulatory framework to tackle the threat of biological invasions, its successful implementation will mainly rely upon appropriate national enforcement and allocation of economic and human resources. Despite previous warnings, the creation of dedicated EU funding mechanisms to support a comprehensive implementation of the legislation still remains a priority. Due to the yet small number of IAS regulated at the EU level, prevention and management of IAS will largely depend on national and local administration efforts, and on regional coordination and cooperation across neighbouring countries. Therefore, a wellintegrated system responsible for biosecurity, pests and invasive alien organisms at the EU level would be better accomplished through a centralized, independent EU agency of new creation. Likewise, the establishment of a similar lead agency at the MS level, with special focus on IAS management in Natura 2000, is recommended to navigate the existing complex regulatory framework.