Long term data collection program for rays and skates in the framework of the Landing obligation (RAYWATCH)
The goal of RAYWATCH is to collect data on skates and rays at the species level, specifically regarding the extent of discards after capture and the percentage that survive in the process. In this way, the researchers will arrive at a scientific basis for arguing for or against an exemption to the landing requirement for undersized fish, based on proven high survival after discarding. A second goal is to integrate the data into scientific population dynamics models. This will enable us to give better advice on the more correct management of - for Belgian fisheries - commercially interesting species of skate and ray.
During the 'national data collection1' campaign extended for this project (marine observers on research vessels) and during additional sea voyages, we make catch analyses on rays. We record detailed data on biological parameters from each ray caught. We use an innovative and efficient data collection system based on the integration of electronic tools (i.e. toughbooks linked to a measuring board). Smart camera images are used to minimize catch manipulation. We identify "choke" situations by rays, based on catch statistics and quota allocations. We eliminate knowledge gaps identified in the "Roadmap for skates and rays." We analyze the newly collected data and integrate them into new stock assessment tools. Based on the obtained results, we formulate recommendations for future sustainable management of the various skate and ray populations.
This project is based on a collaboration between science (ILVO) and sector (Belgian fisheries) and provides a targeted and efficient data collection for commercially important ray species within the framework of "Roadmap for rays and skates" and the renewed DCF using state-of-the-art technologies. Raywatch also serves as a case study for a more automated data collection that will be applicable to other species within the context of the revision of the DCF. This renewed and efficient data collection will allow a more precise estimation of the catch composition and stock size. Using the newly collected data, knowledge gaps within the "Roadmap for rays and skates" can be filled. These can then be integrated into stock assessment models that will eventually lead to more accurate advice for rays.