Management options for the unfavorable nutrient balance of recreational fishing in Lake Balaton (Hungary)

ABSTRACT

Various types of ground baits are loaded to lakes by anglers, but the ecological role of these materials is often overlooked. Thus, the aims of this study were to conduct a quantitative and qualitative assessment of the baits used by anglers in the largest lake of Central-Europe (Lake Balaton, Hungary), estimate the annual nutrient balance of recreational fishing, and relate the nutrient loading from this source to the total external load. Our study demonstrated that popular angler baits varied substantially in their nutrient contents and in their molar nitrogen to phosphorus (N:P) ratios. The net nutrient balance of recreational fishing was +19.3 t total N year⁻¹ and +5.2 t total P year⁻¹, equivalent to 0.7% and 3.2% of the estimated total annual N and P loads, respectively. The rate of nutrient loading may be doubled if the present trends continue: anglers will use 20% more bait with an even higher nutrient content and will also show higher propensity to release the fish after catching. In turn, sustainable nutrient balance of fisheries management could be achieved by limiting the anglers’ bait use to 1.5 kg day⁻¹ and restricting baits to those which have relatively low P (<0.3%) and N (<1.5%) contents.

KEYWORDS:

• Anthropogenic eutrophication
• boilie
• catch-and-release fishing
• fish meal
• sustainable fisheries management

Acknowledgments

The authors thank F. Fodor, M. Hamvasi and G. Nagy (Balaton Fishery Management Nonprofit Ltd.) for their help in online and field surveys on the ground bait use of anglers, and are grateful to the Central-Transdanubian Water Management Directorate of Hungary, and to the Balaton Fishery Management Nonprofit Ltd. for sharing their data. Special thanks to Gabrielle Armin (The University of Rhode Island, USA) for her valuable comments on an earlier version of this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the National Research, Development and Innovation Office of Hungary (under grant: RRF-2.3.1-21-2022-00008) and by the Eötvös Lóránd Research Network (under grant: SA-29/2021).