ORCID ID

https://orcid.org/0000-0002-3811-6506

Date Awarded

2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Virginia Institute of Marine Science

Advisor

Andrew M. Scheld

Committee Member

Troy W. Hartley

Committee Member

Jeffrey D Shields

Committee Member

Miriam Fernandez

Abstract

Marine spatial property rights reduce many common pool externalities that plague wild capture fisheries and incentivize productive use for aquaculture. Specifically, Territorial Use Rights for Fisheries (TURFs) are a management tool whereby individuals or groups are granted exclusive access to harvest resources within an area, and are the prevailing management of coastal fisheries in Chile. Additionally, secured spatial property rights appear inherently obligatory for aquaculture development; i.e., private leases in Virginia, where submerged grounds granted to an individual or a company for oyster production are considered a form of TURF. Although the number and extent of spatially managed areas are the highest they have ever been in both systems, the impacts of spatial property rights on fisheries and aquaculture sustainability are still not fully understood. The objective of this dissertation was to evaluate current challenges to the effective use of TURFs, deepening our understanding of their efficacy for fishery and aquaculture management. The long-term impacts of the Chilean TURFs network on harvests of benthic resources was investigated both inside and outside TURFs (Chapter 2). Although catch rates were significantly higher inside TURFs than surrounding open access areas, they appeared to be decreasing over time, and, though limited, the impact of TURFs on catches in open access areas was negative. Spatio-temporal trends in private lease use and productivity in Virginia were examined to identify challenges faced by the oyster aquaculture industry. Constraints to aquaculture expansion were investigated by evaluating whether a lack of space limits aquaculture development as well as the extent and drivers of lease non-use (Chapter 3). Limited evidence of spatial constraints was found, although results suggest additional social and regulatory limiting factors. While rates of lease use and productivity increased from 2006 to 2016, only 33% of leases were ever used for oyster production. The non-used leases were potentially held for exclusionary or speculative uses. Additionally, Virginia had the second lowest levels of total production of cultured oysters per leased acre among the states along the U.S. East and Gulf coasts, confirming significant limitations associated with the current leasing system. Production frontier models were used to quantify lease use efficiency (i.e., utilization of space given the underlying environment) for oyster production (Chapter 4). Significant amounts of inefficiency in intensive aquaculture practices suggest that production could increase by at least 64% per lease, on average (though high heterogeneity is observed between leases). Low levels of use efficiency (i.e., underutilization) imply that leaseholders tend to lease more area than needed, likely due to the low annual lease costs and the absence of enforced production requirements. The number of leases held per leaseholder increased use efficiency, whereas leases in more populated areas were less efficiently used. This research contributes to a better understanding of TURF's efficacy and challenges in Chile and in Virginia. Overall, socioeconomic and management factors appear to be limiting productivity and sustainability of TURFs in both systems, recognizing the importance of incentives, enforcement, zoning, and the potential presence of trade-offs between economic, social and biological sustainability.

DOI

http://dx.doi.org/10.25773/v5-48dt-1x68

Rights

© The Author

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