No abstracts are to be cited without prior reference to the author.Jellyfish populations are apparently increasing in response to environmental changes (e.g. climate change, eutrophication, overfishing). These increases may ultimately affect commercially important fish stocks. To address this issue it is critical to understand broad-scale distribution and abundance of jellyfish. However, owing to financial and logistical constraints, dedicated jellyfish surveys are rare and alternatives must be found. Here we demonstrate how collaboration with fishery scientists has allowed us to scale-up our jellyfish research from small-scale targeted surveys to effective shelf- and basin-wide studies. Jellyfish bycatch data from the Irish Ground Fish Survey (Irish Marine Institute) have provided new insights into the distribution of the jellyfish Pelagia noctiluca, over a widespread area (>160 000 km2) around Ireland and the UK, where the species has had major impacts on the aquaculture industry. In the northern half of the Irish Sea, we were able to assess basin-wide jellyfish distribution and abundance by using bycatch records from the Methot-Isaacs–Kidd (MIK) Survey for pelagic juvenile gadoids, carried out by AFBI (Agri-Food and Biosciences Institute), Northern Ireland. Such datasets are extremely useful to investigate possible trends in interannual variations of jellyfish abundance, as has successfully been done in few other places in the world. We therefore encourage further development of collaborations between academic marine biologists and fishery scientists in the field, in order to gather enough information to address the current concern about the role of jellyfish in marine ecosystems and their potential impacts on human activities in an effective, robust manner.