Kelp forests are in decline globally and large-scale intervention could be required to halt the loss of these valuable ecosystems. To date kelp forest restoration has had limited success and been expensive and unable to address the increasing scale of ecosystem deterioration. Here we developed and tested a new approach: “green gravel”. Small rocks were seeded with kelp and reared in the laboratory until 2–3 cm, before out-planting to the field. The out-planted kelp had high survival and growth over 9 months, even when dropped from the surface. This technique is cheap, simple, and does not require scuba diving or highly trained field workers. It can be up-scaled to treat large areas or even used to introduce genes from more resilient kelp populations onto vulnerable reefs. Green gravel thus overcomes some of the current major limitations of kelp restoration and provides a promising new defense against kelp forest decline.

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The Pacific oyster Crassostrea gigas has recently expanded its range in Scandinavia. The expansion is presumably a result of northwards larval drift. Massive settlements were recorded in many areas along the Swedish west coast and southern Norway in 2013 and 2014. After the spawning season in 2014, the temperature of the surface water peaked at 24-26°C. After this period, high and sudden mortalities occurred in a Swedish hatchery and in wild populations along the Swedish west coast and south coast of Norway. Surveys and collected data showed that mortalities mainly occurred during 3 wk in September. All size classes were affected, and affected populations displayed a patchy distribution with heavily affected and unaffected populations in close proximity. Flat oysters Ostrea edulis and blue mussels Mytilus edulis were unaffected. Ostreid herpesvirus (OsHV) was detected in moribund Pacific oyster spat as well as in surviving adults. The virus was identified as OsHV-1 μvar. This is the first detection of this variant in Scandinavia, showing that OsHV-1 μvar is present in areas with recent establishments of Pacific oysters, and where there is no aquaculture of this species.

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Most species of bryozoans have short-lived larvae with limited dispersal potential, yet many of these species possess global distributions. In this study, we report the first occurrence from the western Atlantic Ocean of the widely distributed arborescent bryozoan Tricellaria inopinata d 'Hondt and Occhipinti-Ambrogi, 1985. This species was collected in Eel Pond, Woods Hole, Massachusetts, in September 2010. At that time, T. inopinata colonies had already formed dense conspecific aggregations at some collection sites, despite the presence of several other arborescent bryozoans. Sites were monitored throughout 2011 to track the success of this introduction, and to assess the reproductive timing of T. inopinata in Eel Pond. To determine the likelihood of T. inopinata persisting in Eel Pond and competing with previously established bryozoans, rates of metamorphic initiation, metamorphic completion, and overall offspring survivability were compared to one of the other dominant arborescent species. Finally, we provide taxonomic details to aid in identifying these animals, consider the potential mode of transport, and discuss the potential ecological implications resulting from this introduction.