Impacts of metapopulation dynamics on overfishing risk and vulnerability in multiscale fisheries
Presentation Abstract
Fisheries management generally strives to balance tradeoffs between complex economic, social and ecological systems. Yet estimates of overfishing risk under individual harvest guidelines are likely to be biased where the spatial and temporal scales of science and management are improperly aligned with that of either the biology and/or the socioeconomic dynamics of the fishery participants. These biases have the potential to be especially pronounced in the presence of individual sub-stocks (i.e. metapopulation structure). Moreover the consequences of those biases are likely asymmetric when multiple fleets operate at different spatial scales. Specifically fleets targeting the entire metapopulation may be less vulnerable to risky harvest guidelines or naive biological assumptions than those dependent upon a subset of local aggregations. We explore the degree to which bias in overfishing risk and asymmetry in vulnerability among fleets result from the nature of harvest control rules, patterns of synchrony and connectivity among populations, and the scientific uncertainties in spatial and temporal population dynamics using a combination of metapopulation modeling and management strategy evaluation. We first use a basic simulation framework to illustrate how population connectivity, synchrony and harvest guidelines influence both local (single population level) and regional (metapopulation level) overfishing risk and extirpation probabilities. We then apply the models to a case study of Pacific Herring in British Columbia. Here, both transient industrial fishing fleets and local First Nations fleets target a complex suite of herring stocks whose spatial structure is poorly understood at smaller scales. Results are valuable in demonstrating which scenarios may benefit from improved knowledge of the temporal and spatial dynamics of the target species or the risk tolerance of individual fishery fleets.
Session Title
Forage Fish Management and Conservation in the Salish Sea
Conference Track
Species and Food Webs
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Location
2016SSEC
Type of Presentation
Oral
Genre/Form
presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Fisheries--Catch effort--British Columbia; Fish populations--British Columbia--Computer simulation; Pacific herring populations--Monitoring--British Columbia
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Impacts of metapopulation dynamics on overfishing risk and vulnerability in multiscale fisheries
2016SSEC
Fisheries management generally strives to balance tradeoffs between complex economic, social and ecological systems. Yet estimates of overfishing risk under individual harvest guidelines are likely to be biased where the spatial and temporal scales of science and management are improperly aligned with that of either the biology and/or the socioeconomic dynamics of the fishery participants. These biases have the potential to be especially pronounced in the presence of individual sub-stocks (i.e. metapopulation structure). Moreover the consequences of those biases are likely asymmetric when multiple fleets operate at different spatial scales. Specifically fleets targeting the entire metapopulation may be less vulnerable to risky harvest guidelines or naive biological assumptions than those dependent upon a subset of local aggregations. We explore the degree to which bias in overfishing risk and asymmetry in vulnerability among fleets result from the nature of harvest control rules, patterns of synchrony and connectivity among populations, and the scientific uncertainties in spatial and temporal population dynamics using a combination of metapopulation modeling and management strategy evaluation. We first use a basic simulation framework to illustrate how population connectivity, synchrony and harvest guidelines influence both local (single population level) and regional (metapopulation level) overfishing risk and extirpation probabilities. We then apply the models to a case study of Pacific Herring in British Columbia. Here, both transient industrial fishing fleets and local First Nations fleets target a complex suite of herring stocks whose spatial structure is poorly understood at smaller scales. Results are valuable in demonstrating which scenarios may benefit from improved knowledge of the temporal and spatial dynamics of the target species or the risk tolerance of individual fishery fleets.
