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Citations since 2017
11 Research Items
Research Interests: Fisheries & aquaculture management; Small-scale fisheries co-management; Social-Ecological Systems; Global change adaptations; Territorial Use Rights for Fisheries; Marine Spatial Planning; Interactions Fisheries/ Offshore energy.
Beginning in the 1990’s, Chile implemented an extensive Territorial User Rights for Fisheries (TURFs) network that now comprises nearly 1,000 TURFs. This network provides a rare opportunity to examine spatial and temporal trends in TURF use and impacts on surrounding open access areas (OAAs). In this analysis, landings of keyhole limpet (Fissurella...
The eastern oyster once provided major societal and ecosystem benefits, but these benefits have been threatened in recent decades by large declines in oyster harvests. In many areas, recovery of oyster aquaculture faces significant societal opposition and spatial constraints limiting its ability to meet expectations regarding future food needs and...
During the last decade, oyster aquaculture has rebounded in Virginia and has been associated with an increase in subaqueous leased area. Production levels remain historically low, however, and many leases are thought to be underutilized. This study uses a novel approach leveraging high-resolution environmental data to evaluate lease utilization and...
The Atlantic surfclam (Spisula solidissima) fishery generates approximately USD 30 million in landings revenues annually, distributed across ports throughout the US Mid-Atlantic and Northeast. Overlap between areas of Atlantic surfclam harvests and offshore wind energy leasing make the fishery vulnerable to exclusion and effort displacement as deve...
The dynamics of marine systems at decadal scales are notoriously hard to predict—hence references to this timescale as the “grey zone” for ocean prediction. Nevertheless, decadal-scale prediction is a rapidly developing field with an increasing number of applications to help guide ocean stewardship and sustainable use of marine environments. Such p...
Competing pressures imposed by climate-related warming and offshore development have created a need for quantitative approaches that anticipate fisheries responses to these challenges. This study used a spatially explicit, ecological-economic agent-based model integrating dynamics associated with Atlantic surfclam stock biology, decision-making beh...
Length‐based methods provide alternatives for estimating the instantaneous total mortality rate (Z) in exploited marine populations when data are not available for age‐based methods. We compared the performance of three equilibrium length‐based methods: the length‐converted catch curve (LCCC), the Beverton–Holt equation (BHE), and the length‐based...
As increasingly large extents of the global oceans are being managed through spatial measures, it is important to identify area characteristics underlying network distributions. Studies discerning spatial patterns in marine management have disproportionately focused on global networks. This paper instead considers the single country context of Japa...
Excessive truncation of a population’s size structure is often identified as an important deleterious effect of exploitation, yet the effect of this truncation on population persistence is seldom quantified. In this study, we estimate changes in eggs per recruit (EPR) using annual length-frequency samples over a 9 year period to assess persistence...
I know that using non-discretionary input could be an issue in the original, input-oriented DEA models where input can be expanded and/or contracted. The concern, I think, was that we don't want to produce efficiency scores suggesting efficiency could be improved by reducing uncontrollable (non-discretionary) inputs. However, I wonder if the inclusion of non-discretionary input is as consequential for output-oriented VRS DEA models? Most of the literature is based on input-oriented DEAs. Any comments will be appreciated, Thanks.
I am performing a Stochastic Frontier Analysis on unbalanced panel data in R with the package frontier (based on Battese & Coelli 95). I wonder how can we check for autocorrelation / endogeneity. The residuals() function returns the residuals, which consist of both the noise term and the inefficiency term, i.e. residual = y - f(x) = v - u. I am not sure if one can use these residuals to test for heteroscedasticity (Breush-Pagan test) or autocorrelation (LM test). Have you seen this in the literature?
I am running a beta regression, my dependent variable is a proportion, beta-distributed such as y ~ B (µ,ɸ ), with µ its mean and ɸ, a constant precision parameter; the link function used, g(.), was logit. Pseudo-R2 was estimated 0.97 reflected that the goodness-of-fit measured from the beta regression was strong. ɸ was evaluated as 242.04. I know the larger ɸ the smaller the variance of y. But how to define "large ɸ"?
My delta (or hurdle) model will include two components:
- the probability p of a farm to be used using a logit model and where zero data are farms not used and,
- the efficient production (or the extent to which a farm is inefficient) given that a farm is used (applied to the non-zero data). I am not including the zeros in the SPF because different processes likely affect use/non-use and the degree to of use.
The delta model will give a probability of use (p) and SPF will give predicts of inefficient and efficient output levels. I could use both of these predictions, e.g., the difference between p(use)*efficient and p(use)*inefficient says something about the inefficiency/social costs.
I would love to chat with someone who has done something similar.
This project investigates how fishers and fishery management institutions have responded to large-scale changes (ecological, economic and/or political driven changes). One specific question that this research aims to answer is how institutional and governance mechanisms can facilitate or limit fisher’s adaptation to changes. A balanced-method approach formed of conceptual bio-economic models and institutional analyses will allow for a more comprehensive assessments of the long-term responses of fisheries systems, identifying key adaptation processes at the sector, community and institutional levels.
A case study of the oyster leases utilization in Chesapeake Bay (US) and the MEABR -Management and Exploitation Areas for Benthic Resources- challenges along the Chilean coast.