Final Report Summary - FISBOAT (Fisheries independent survey based operational assessment tools)
Conventional fish stock assessments are based on commercial catch data; however, they cannot always provide reliable estimates, due to misreporting discards, collapse of stocks and lack of historical data for several species. The FISBOAT project aimed to address these issues and develop assessment tools, namely software and documentation, based solely on fishery independent research survey data. The proposals were evaluated in terms of their potential to provide diagnostics and advice in different management contexts.
Indices of demography, total mortality, spatial occupation and biological traits were produced. Changes in the indices' time-series were monitored and interpreted. The developed techniques were based on various data, such as biomass, sample length and sample age and allowed for the estimation of abundance, catch ability and mortality indicators. The project implemented a multidisciplinary approach and evaluated its findings via both simulations and case studies' examination.
Three categories of methods were used, namely assessment models, monitoring procedures and simulation evaluation tools. The first two provided relative diagnostics, while the latter allowed for the investigation of management options. The finalised methodologies were included in detailed manuals to assist monitoring and management of fish stocks using an ecosystem approach.
Indicators that represented biological and spatial attributes of stocks were selected during the first project stage and techniques for their calculation were conceptualised. Methods to statistically support the observed trends and changes within the time series were also identified, including the construction of multivariate indices. Their assessment was feasible via combination of the analyses' results in predefined tables and their performance depended on the nature of the time series' variability. Nevertheless, the tools were able to successfully provide stock evaluations under all examined conditions.
Furthermore, models that utilised only abundance indicators were tested. A series of options with different data requirements and mortality assumptions was analysed. The models smothered noisy indices and reliably captured major signals in biomass and recruitment. Moreover, they provided useful evidence on trends even though they did not offer absolute estimates of the stocks' size.
An internet-based evaluation platform was also developed, which implemented consecutive operating, observation and harvest control rule (HCR) models that interacted in a dynamic simulation loop. An option for visual analysis of the outcomes was also available. The framework was applied on selected stocks, showing that HCR estimates had to be conservative in systems with high variability in order to be reliable.
An age-based population operating model was additionally designed, considering age to length conversion and formulating length-dependent natural mortality, fecundity and gear selectivity. The model was mostly applicable in the Mediterranean; nevertheless, it was evaluated in various European stocks. A stochastic version was also offered, to include uncertainties in biological parameters, which were identified as random variables. Finally, a protocol for implementing a comprehensive assessment procedure based on survey data was produced.
FISBOAT results were disseminated via numerous activities, such as preparation and publication of documents and journals' special volumes, participation in conferences and working groups and development and updating of a specific website. The latter was essential for dissemination purposes and would remain active after the project completion. The generated outcomes were anticipated to influence significantly the fishing sector, as well as to be expanded and incorporated in future research efforts.
Indices of demography, total mortality, spatial occupation and biological traits were produced. Changes in the indices' time-series were monitored and interpreted. The developed techniques were based on various data, such as biomass, sample length and sample age and allowed for the estimation of abundance, catch ability and mortality indicators. The project implemented a multidisciplinary approach and evaluated its findings via both simulations and case studies' examination.
Three categories of methods were used, namely assessment models, monitoring procedures and simulation evaluation tools. The first two provided relative diagnostics, while the latter allowed for the investigation of management options. The finalised methodologies were included in detailed manuals to assist monitoring and management of fish stocks using an ecosystem approach.
Indicators that represented biological and spatial attributes of stocks were selected during the first project stage and techniques for their calculation were conceptualised. Methods to statistically support the observed trends and changes within the time series were also identified, including the construction of multivariate indices. Their assessment was feasible via combination of the analyses' results in predefined tables and their performance depended on the nature of the time series' variability. Nevertheless, the tools were able to successfully provide stock evaluations under all examined conditions.
Furthermore, models that utilised only abundance indicators were tested. A series of options with different data requirements and mortality assumptions was analysed. The models smothered noisy indices and reliably captured major signals in biomass and recruitment. Moreover, they provided useful evidence on trends even though they did not offer absolute estimates of the stocks' size.
An internet-based evaluation platform was also developed, which implemented consecutive operating, observation and harvest control rule (HCR) models that interacted in a dynamic simulation loop. An option for visual analysis of the outcomes was also available. The framework was applied on selected stocks, showing that HCR estimates had to be conservative in systems with high variability in order to be reliable.
An age-based population operating model was additionally designed, considering age to length conversion and formulating length-dependent natural mortality, fecundity and gear selectivity. The model was mostly applicable in the Mediterranean; nevertheless, it was evaluated in various European stocks. A stochastic version was also offered, to include uncertainties in biological parameters, which were identified as random variables. Finally, a protocol for implementing a comprehensive assessment procedure based on survey data was produced.
FISBOAT results were disseminated via numerous activities, such as preparation and publication of documents and journals' special volumes, participation in conferences and working groups and development and updating of a specific website. The latter was essential for dissemination purposes and would remain active after the project completion. The generated outcomes were anticipated to influence significantly the fishing sector, as well as to be expanded and incorporated in future research efforts.
