Most fish caught by recreational anglers will typically survive the experience of being caught and released, whereas for other gears the survival rate can be anything from 0 to 100% dependent on the gear type and handling: "It is widely known that fish survival depends on a multitude of factors, including: fishing gear, fish speed, tow time, water temperature, types of sea floor, processing, exposure to air, fish condition and body length"; cutting from "The Landing Obligation and Its Implications on the Control of Fisheries" (2015) by the European Parliament's Policy Department B: Structural and Cohesion Policies, Fisheries.
The discard ban arguably only applies to commercial fisheries. Nevertheless, catch and release data are required by the Data Collection Framework with regard to some species (cod, Bluefin tuna, salmon, eels, sea bass and sharks) and by the CFP for stock assessment of these and other species: "A large proportion of recreational catch is often released, so accurate estimates of post-release mortality are also required for stock assessment. Post-release mortality is difficult to measure and is dependent on many factors including capture depth, gear, and species. More studies are needed in this area." "Recreational sea fishing – the high value forgotten catch " (2014) - by K. Hyder, M. Armstrong, K. Ferter and H. V. Strehlow; p. 8.