Biotic interactions such as predation are difficult ecological processes to quantify in the wild. This is especially the case in the marine environment due to logistical difficulties in capturing animal behaviour. Common approaches use aquarium‐based experiments, live‐tethering, or assays with bait as proxies for quantifying predation pressure. However, these methods often fail to account for natural interactions between species in the wild and may raise ethical and animal welfare concerns. We designed a novel field‐based method to quantify predator–prey interactions for marine fishes. The “predation dome” is a clear acrylic aquarium that contains a live fish. The dome is filmed and, in contrast to other methods, it allows for natural olfactory and visual cues, and the prey fish is returned to the wild after the assay. Here, we provide a step‐by‐step guide on building and deploying the predation dome in the wild. To demonstrate its use, we quantified predation pressure using the domes in two tropical and two temperate locations. Piscivores were attracted to the domes and displayed predatory behaviours such as circling or striking. Although the overall number of predatory attacks did not differ among locations, predation domes revealed higher predation pressure by piscivores at the tropical locations in comparison to temperate reefs. Our results show that predation domes represent an ethical and complementary approach to measure predation that may better represent piscivory as compared to other behaviours. Predation domes can be also used to measure other biotic interactions such as territorial defence or courtship.

Fucus virsoides is an endemic species of the Mediterranean limited to the Adriatic Sea. In recent decades, it has undergone a severe regression, which is well documented in the northern Adriatic. To develop a tool for mitigating this problem, we tested the feasibility of F. virsoides restoration and designed a very simple yet effective method for ex situ cultivation and planting. We also tested the effect of positioning in the upper vs. lower intertidal on the growth of F. virsoides. After planting, the algae reached fertility in nine months, which was followed by a period of stagnation and reduction in size due to grazing and fouling. There were some differences in growth of the algae according to positioning in the intertidal at different measurement times, but that had little impact on the overall success of the restoration experiment. This represents, to our knowledge, the first successful F. virsoides ex situ cultivation and restoration attempt.