Tag Archives: decision trees; cause and consequences; fisheries; spatial effort

How individual fishermen´s micro-decision-making affects the overall performance of fisheries

Fishermen´s micro-decision-making is challenged by fishery management and marine spatial plans and affects the overall performance of fisheries. Because of individual decisions and tactics for fishing (e.g. selection of gears, place and time) influence catching power, the fishermen have individual footprint on the harvested stocks and benthic communities.

Also, fishermen have different objectives and strategies influencing economic performance of the fishery for several stocks and in different areas. By regulating catch quotas, the deployed effort and potential fishing grounds, both fisheries management and marine spatial plans can result in unintended consequences and incentives affecting the overall economic and energy performance of the fisheries at stake, which may further undermine the ecosystem approach to fisheries.

We intend to support the fishery sector and the policy makers with a benchmark tool for efficiently evaluating alternative scenarios in individual decision making, by designing decision trees to model when, where, how, and for how long they go fishing.

This allows sensitivity experimentation of several factors determining fisheries including the vessel´s internal states and various external constraints such as spatial and seasonal resource conditions, fish and fuel price, weather conditions and spatial plans. User-made decision trees are embedded within the broader DISPLACE individual vessel-based spatial modelling approach (2014, 71: 366-386 in Can. J. Fish. Aqu. Sci.; Screenshot version 0.7.15) screenshot_Displace_v0715 which offers an evaluation of the consequences of alternative dynamics in vessel movements using information about fishing ground preferences and vessel-specific experienced catch rates.

In order to support a quantitative analysis for the generalization of impacts at the macro-scale from all the micro-decisions taken by the vessels aggregated, a spectrum of decision trees and trigger events are attached to the vessels.