A1 Journal article (refereed)
Towards sustainable commercial vendace fisheries in Finland : lessons learned from educating stakeholders for management decision making based on imprecise stock monitoring data (2021)

Marjomäki, T. J., Valkeajärvi, P., Keskinen, T., Muje, K., Urpanen, O., & Karjalainen, J. (2021). Towards sustainable commercial vendace fisheries in Finland : lessons learned from educating stakeholders for management decision making based on imprecise stock monitoring data. Advances in Limnology, 66, 25-46. https://doi.org/10.1127/adv_limnol/2021/0068

JYU authors or editors

Publication details

All authors or editors: Marjomäki, Timo J.; Valkeajärvi, Pentti; Keskinen, Tapio; Muje, Kari; Urpanen, Olli; Karjalainen, Juha

Journal or series: Advances in Limnology

ISSN: 1612-166X

Publication year: 2021

Publication date: 15/12/2021

Volume: 66

Pages range: 25-46

Publisher: Schweizerbart

Publication country: Germany

Publication language: English

DOI: https://doi.org/10.1127/adv_limnol/2021/0068

Publication open access: Not open

Publication channel open access:

Abstract

The new Fishing Act in Finland stipulates that fisheries must be managed in an ecologically, economically, and socially sustainable manner based on the best available knowledge. A new regional body representing different stakeholders must prepare a management plan, enforce it, and monitor its impact with data on fisheries. To facilitate these objectives, representatives of different stakeholder groups and other relevant actors were educated for whole-lake-scale vendace (Coregonus albula) stock monitoring and commercial fisheries management planning, and decision-making. The education sessions consisted of lectures on stock monitoring methods and a practical exercise of preparing a monitoring plan and a commercial fishing code. These were then pressure tested and tuned further in management strategy evaluation (MSE); A simulation model was used to create a virtual vendace stock and associated fishing and stock monitoring data that incorporated realistic measurement errors and biases. The participants applied these imprecise data for regulating fishing according to their code. First, this paper provides an example of real vendace monitoring data from Lake Southern Konnevesi. The stock has been monitored with metrics such as yield (kg) and catch (individuals) per unit effort, age distribution, and size-at-age. Later on, density of newly hatched larvae after ice-off and pelagic fish density in autumn (consisting mainly of vendace and smelt) were estimated annually. Despite the considerable imprecision, all abundance indices correlated strongly and indicated the trend in vendace stock abundance. The larval density estimate gave some useful information for back-casting spawning stock abundance and forecasting recruitment. The participants of the exercise felt, based on their experience, that annual data on total commercial yield and fishing effort, YPUE from commercial gear, age-distribution of catch, and size-at-age are minimum annual information required for understanding relative stock fluctuations and for forecasting the potential for sustainable fishing for next season. These were considered cost-effective and heuristically simple to interpret. In certain demanding situations, they found stakeholder-independent information on larval density and vendace density from echo sounding useful, despite their higher cost and more ambiguous interpretation. The exercises generated valuable information on what should be included in a lake-specific commercial vendace fishing code and on an applicable management strategy for a quickly fluctuating vendace resource. The MSE turned out to be useful both in educating the participants about planning and decision-making and testing and fine-tuning the draft of a monitoring plan and fishing code.

Keywords: fishing; fish populations; tracking; measurement; professional fishing; effects (results); ecological sustainability; Fishing Act; decision making

Free keywords: biological reference point; coregonid; harvest strategy; stock assessment; uncertainty

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2021

JUFO rating: 1