Juan J. Agar

Evidence of climate-driven ecosystem reorganization in the Gulf of Mexico

The Gulf of Mexico is one of the most ecologically and economically valuable marine ecosystems in the world and is affected by a variety of natural and anthropogenic phenomena including climate, hurricanes, coastal development, agricultural runoff, oil spills, and fishing. These complex and interacting stressors, together with the highly dynamic nature of this ecosystem, present challenges for the effective management of its resources. We analyze a compilation of over 100 indicators representing physical, biological, and economic aspects of the Gulf of Mexico and find that an ecosystem-wide reorganization occurred in the mid-1990s. Further analysis of fishery landings composition data indicates a major shift in the late 1970s coincident with the advent of US national fisheries management policy, as well as significant shifts in the mid-1960s and the mid-1990s. These latter shifts are aligned temporally with changes in a major climate mode in the Atlantic Ocean: the Atlantic Multidecadal Oscillation (AMO). We provide an explanation for how the AMO may drive physical changes in the Gulf of Mexico, thus altering higher-level ecosystem dynamics. The hypotheses presented here should provide focus for further targeted studies, particularly in regard to whether and how management should adjust to different climate regimes or states of nature. Our study highlights the challenges in understanding the effects of climatic drivers against a background of multiple anthropogenic pressures, particularly in a system where these forces interact in complex and nonlinear ways.

The Gulf of Mexico Red Snapper IFQ Program: The First Five Years

ABSTRACT The Gulf of Mexico red snapper individual fishing quota program was implemented in 2007 to reduce overcapacity and eliminate derby fishing conditions in the commercial fishery. The five-year review of the program reveals that the number of vessels and fishing trips declined by 17% and 29%, respectively. The review also found the fishery was open year round for the first time in 20 years. Between 2007 and 2011, inflation-adjusted dockside, allocation (leased quota), and quota share prices rose by 7%, 37%, and 145%, respectively, suggesting the profitability of the fleet improved. Gini and Herfindahl-Hirschman indices indicate the distribution of shares is highly unequal, but shareholders do not have market power. The absence of quota overages and lower aggregate discard levels suggest resource stewardship improved. However, discards in the eastern Gulf remain high due to stock range expansion and insufficient allocation. This article also describes lessons learned from the five-year review. JEL Codes: Q22, Q58.