A carp angler survey indicated that specialised carp anglers used on average 215 kg groundbaits (mostly cereals, nuts, beans, boilies) per year which corresponded to a mean annual gross P-input of 1018 g P angler )1 . A feeding experiment was conducted with juvenile carp fed with a random sample of the main bait types used in coarse angling to estimate the nutritional quality and P-retention efficiency. The investigated groundbaits had a rather low nutritional quality. Based on the examined P-retention efficiencies, the net annual P-input was calculated to be 839 g P per angler. To counterbalance this P-input, an annual harvest rate of 175-225 kg carp biomass per angler would be necessary. Thus, under certain conditions, a substantial contribution by carp and other coarse angling to the P-loading is likely. Further studies on the issue of groundbaiting are needed to develop guidelines for more effective management of coarse angling. K E Y

To evaluate the suitability of angling groundbaits as a fish feed and the potential for nutrient loss, the macronutrient digestibility of four groundbaits was investigated in carp, Cyprinus carpio L., using a sieving method of faeces collection and chromic oxide. Apparent digestibility coefficients (ADCs) of protein and lipids were >80% for all angling baits. ADCs of nitrogen-free extracts and phosphorus (P) differed significantly between the test diets, probably because of divergent feed compositions and ingredient treatments. The generally high digestibility estimates indicated that fish feeding on angling groundbait will benefit from this food source. The differences in nutrient digestibility suggested that type of groundbait and ingredient used will have a major effect on potential eutrophication and fish production caused by groundbaiting. The principle of groundbaits to protect the environment should be to minimise the P-content of the groundaits and maximising P-digestibility and P-retention efficiency. K E Y W O R D S :Fisheries Management and Ecology, 2005, 12, 91-97