Enteric redmouth disease (ERM), caused by Yersinia ruckeri, is among the most important infectious diseases in rainbow trout Oncorhynchus mykiss aquaculture in Europe. Our aim was to analyse the persistence of Y. ruckeri strains in trout farms in northwest Germany and their dissemination between farms based on a detailed molecular and phenotypical characterisation scheme. The data on identification and characterisation of Y. ruckeri strains and examining the distribution of these strains in the field could serve as a basis for preventive disease monitoring plans. During the observation period from June 2011 until June 2012, we collected 48 Y. ruckeri isolates from 12 different rainbow trout hatcheries. In total, 44 (91.7%) of the isolates were nonmotile; in particular, all isolates recovered during the sampling period in winter and early spring were non-motile. In several trout farms, characteristic farm-specific Y. ruckeri isolates from particular typing groups were isolated throughout the year, while in other farms, which had a trading relationship between each other, ERM outbreaks were caused by Y. ruckeri from the same typing group. Our data indicate that in some farms, the causative Y. ruckeri strains persisted in the respective trout farm. The presence of Y. ruckeri from the same typing group in farms with a trading relationship indicates a dissemination of the infection between the farms. KEY WORDS: Epidemiology · Enteric redmouth disease · Rainbow trout · Oncorhynchus mykissResale or republication not permitted without written consent of the publisher FREE REE ACCESS CCESS

Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.

Identifying animal foraging habitat can help prioritise areas for conservation and enable better predictions of how populations respond to environmental change. Recent reductions in the size of biologging devices now enable fine-scale foraging habitat tracking for very small seabirds. We investigated the foraging distribution and habitat preferences of Monteiro’s storm-petrel Hydrobates monteiroi, a tiny (<60 g), vulnerable seabird that is endemic to the Azores Archipelago. We tracked 67 storm-petrels with 108 GPS deployments across 4 consecutive breeding seasons (2018-2021) to identify important foraging areas and preferences for dynamic and static features of their mid-ocean environment. We found that static bathymetric features such as seafloor depth and distance from the nearest seamount were the most important predictors of foraging location, suggesting that topographic features may provide areas of enhanced biological productivity in the mid-Atlantic Ocean that are predictable across long timescales. Although dynamic oceanographic variables (sea surface temperature and chlorophyll a) also helped predict foraging activity, both the location and environmental characteristics of foraging habitat were relatively stable across 4 consecutive years. This suggests that meso-scale oceanographic dynamics do not drive strong interannual variation in foraging behaviour in this system. Currently, only 11.4% of Monteiro’s storm-petrel foraging locations overlap with designated marine protected areas. A total of 95% of unprotected foraging locations fell within the Azores exclusive economic zone (EEZ), indicating a responsibility of the Portuguese government to increase habitat protection. Our findings suggest that more comprehensive at-sea conservation for this vulnerable species could be focused in predictable geographic areas over the mid-Atlantic ridge and seamounts.