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• 1. [Article] The Effects of Derelict Gear on Blue Crab Production in the Chesapeake Bay

  Several factors currently threaten blue crab (Callinectes sapidus) in the Chesapeake Bay. In addition to poor water quality, degraded habitat, and shifting environmental conditions, derelict gear has recently ...

  Citation × Citation Citation Abstract Copy Title: The Effects of Derelict Gear on Blue Crab Production in the Chesapeake Bay Author: Bilkovic, Donna M., Scheld, Andrew M., Havens, Kirk J. Several factors currently threaten blue crab (Callinectes sapidus) in the Chesapeake Bay. In addition to poor water quality, degraded habitat, and shifting environmental conditions, derelict gear has recently been recognized as a significant source of mortality for this economically and culturally significant species. From 2008 through 2014, commercial watermen in Virginia were hired during their winter off season to locate, document, and remove derelict gear as part of a larger research effort to determine the biological impacts of marine debris in the Chesapeake Bay. Data on derelict gear removal generated by this research was subsequently paired with spatially resolved catch and effort data and entered into a translog production model used to estimate the economic effects of derelict gear on commercial blue crab production. Model results indicate removal significantly improved pot production and economic profits, a finding which had been previously confounded by concurrent blue crab management action. Our research builds on previous work through explicit acknowledgment of important spatial production differences and incorporation of derelict gear removal. Title: The Effects of Derelict Gear on Blue Crab Production in the Chesapeake Bay Author: Bilkovic, Donna M., Scheld, Andrew M., Havens, Kirk J. Several factors currently threaten blue crab (Callinectes sapidus) in the Chesapeake Bay. In addition to poor water quality, degraded habitat, and shifting environmental conditions, derelict gear has recently been recognized as a significant source of mortality for this economically and culturally significant species. From 2008 through 2014, commercial watermen in Virginia were hired during their winter off season to locate, document, and remove derelict gear as part of a larger research effort to determine the biological impacts of marine debris in the Chesapeake Bay. Data on derelict gear removal generated by this research was subsequently paired with spatially resolved catch and effort data and entered into a translog production model used to estimate the economic effects of derelict gear on commercial blue crab production. Model results indicate removal significantly improved pot production and economic profits, a finding which had been previously confounded by concurrent blue crab management action. Our research builds on previous work through explicit acknowledgment of important spatial production differences and incorporation of derelict gear removal. Close

• 2. [Article] Competitive Markets in Stochastic Environments: Will Climate Change Drive Industry Consolidation of Global Fisheries?

  Climate change and continued fishing pressure threaten to increase recruitment variability for many stocks globally. Shifts in the inter-annual stability of an exploitable renewable resource may have dramatic ...

  Citation × Citation Citation Abstract Copy Title: Competitive Markets in Stochastic Environments: Will Climate Change Drive Industry Consolidation of Global Fisheries? Author: Scheld, Andrew M. Climate change and continued fishing pressure threaten to increase recruitment variability for many stocks globally. Shifts in the inter-annual stability of an exploitable renewable resource may have dramatic consequences for the industries and communities which depend upon them. In this talk, the link between resource volatility and industry structure is explored using two models. First, an agent-based simulation model is presented to illustrate the effects of increasing resource variation on the number of participants in an extractive industry. Model output depicts a causal relationship between resource stability and industry structure, showing few industry participants when the resource is highly variable. Several other structural components of the model are additionally explored and suggest policy prescriptions that may mitigate environmentally driven industry effects. A second model is also presented which empirically investigates the relationship between resource volatility and industry consolidation. Here we apply tools from portfolio theory to global fisheries production and employment data, finding countries which exhibit higher portfolio volatility in production across different species groups tend to employ fewer people in their fishing industries. Both models suggest a strong link between environmental stability and the structure of resource dependent industries, indicating a need for proactive policies to address anticipated effects of climate change. Title: Competitive Markets in Stochastic Environments: Will Climate Change Drive Industry Consolidation of Global Fisheries? Author: Scheld, Andrew M. Climate change and continued fishing pressure threaten to increase recruitment variability for many stocks globally. Shifts in the inter-annual stability of an exploitable renewable resource may have dramatic consequences for the industries and communities which depend upon them. In this talk, the link between resource volatility and industry structure is explored using two models. First, an agent-based simulation model is presented to illustrate the effects of increasing resource variation on the number of participants in an extractive industry. Model output depicts a causal relationship between resource stability and industry structure, showing few industry participants when the resource is highly variable. Several other structural components of the model are additionally explored and suggest policy prescriptions that may mitigate environmentally driven industry effects. A second model is also presented which empirically investigates the relationship between resource volatility and industry consolidation. Here we apply tools from portfolio theory to global fisheries production and employment data, finding countries which exhibit higher portfolio volatility in production across different species groups tend to employ fewer people in their fishing industries. Both models suggest a strong link between environmental stability and the structure of resource dependent industries, indicating a need for proactive policies to address anticipated effects of climate change. Close