Browsing by Author "Read, Andrew J"

A vast range of theoretical and empirical studies now suggests that MPAs can conserve marine biodiversity and, under some circumstances, increase fishery yields. However, despite the importance of pelagic apex predators to ecosystem function, the effectiveness of spatial management for the conservation of pelagic apex predator species is still unknown. I used fishery-dependent logbook and observer datasets to assess fishing effort and both the catch and size of pelagic apex predator species around five different MPAs. The US Hawaii-based deep-set or Atlantic pelagic longline fisheries fish the waters around these MPAs; both of these fisheries have experienced multiple management measures over time to protect species and maximize fishery yield. The MPAs selected for this study range in size, age, level of protection, and reason for establishment. I found that only two MPAs of the five appeared to be benefitting the pelagic apex predator species that I selected: the DeSoto Canyon and East Florida Coast MPAs, both in the Atlantic Ocean. The size of yellowfin tuna around the DeSoto Canyon MPA borders has increased over time, as has fishing effort. In contrast, the size of swordfish has decreased near the boundary of the East Florida Coast MPA, although the catch of swordfish has increased. The increase in catch of smaller swordfish was not a surprise because the East Florida Coast MPA was established around an area that is a nursery habitat for swordfish. These results are promising for the use of static MPAs for the conservation of pelagic apex predators, but three of the MPAs in my study did not show any indication of increased fishing effort, increased catch, or changes in pelagic apex predator size near their boundaries over time. Therefore, the characteristics of the DeSoto Canyon and East Florida Coast MPAs may provide a template for how to best design new MPAs for pelagic apex predators. Both of these MPAs were established with the specific intent of reducing pelagic apex predator bycatch, in areas where there were historically high catch rates. Both areas are relatively large (> 85,000 km2) and are also closed year-round. In combination, these characteristics may provide protection for pelagic apex predators.

There have been few efforts to evaluate the actual and perceived effectiveness of environmental management programs created by consensus-based, multi-stakeholder negotiation or negotiated rulemaking. Previous evaluations have used perceived success among participants as a proxy for actual effectiveness, but seldom have investigated the ecological outcomes of these negotiations. Fewer still, if any, have compared the actual and perceived outcomes. Here I evaluate and compare the social and ecological outcomes of the negotiated rulemaking process of marine mammal take reduction planning. Take reduction planning is mandated by the U.S. Marine Mammal Protection Act (MMPA) to reduce the fisheries-related serious injuries and mortalities of marine mammals (bycatch) in U.S. waters to below statutory thresholds. Teams of fishermen, environmentalists, researchers, state and federal managers, and members of Regional Fisheries Management Councils and Commissions create consensus-based rules to mitigate bycatch, called Take Reduction Plans. There are six active Take Reduction Plans, one Take Reduction Strategy consisting of voluntary measures, and one plan that was never implemented. It has been 20 years since marine mammal take reduction planning was incorporated into the MMPA. Early evaluations were promising, but identified several challenges. In the past decade or more, the National Marine Fisheries Service (NMFS) has implemented measures to set up the teams for success.

I used data from formal Stock Assessment Reports to assess and rank the actual ecological success of five Take Reduction Plans (Harbor Porpoise, Bottlenose Dolphin, Atlantic Large Whale, Pelagic Longline, and Pacific Offshore Cetacean) in mitigating the bycatch of 17 marine mammal stocks. In addition, I employed social science data collection and analytical methods to evaluate Take Reduction Team participants' opinions of the take reduction negotiation process, outputs, and outcomes with respect to the ingredients required for successful multi-stakeholder, consensus-based negotiation (team membership, shared learning, repeated interactions, facilitated meetings, and consensus-based outputs). These methods included surveying and interviewing current and former Take Reduction Team participants; using Structural Equation Models (SEMs) and qualitative methods to characterize participant perceptions across teams and stakeholder groups; and identifying and exploring the reasons for similarities and differences among respondents, teams, and stakeholder groups. I also employed SEMs to quantitatively examine the relationship between actual and perceived ecological success, and contrasted actual and perceived outcomes by comparing their qualitative rankings.

Structural Equation Models provided a valid framework in which to quantitatively examine social and ecological data, in which the actual ecological outcomes were used as independent predictors of the perceived outcomes. Actual improvements in marine mammal bycatch enhanced stakeholder opinions about the effectiveness of marine mammal Take Reduction Plans. The marine mammal take reduction planning process has all of the ingredients necessary for effective consensus-based, multi-stakeholder negotiations (Chapter 2). It is likely that the emphasis that the National Marine Fisheries Service places on empirical information and keeping stakeholders informed about bycatch, marine mammal stocks, and fisheries facilitated this relationship. Informed stakeholders also had relatively accurate perceptions of the actual ecological effectiveness of the Take Reduction Plans (Chapter 3). The long timeframes over which the teams have been meeting generally have increased cooperation. The professionally trained, neutral facilitators have produced fair negotiations, in which most individuals felt they had an opportunity to contribute. Participant views of fairness significantly influenced their satisfaction with Take Reduction Plans, which significantly affected their perceptions about the effectiveness of those plans (Chapter 2). The mandate to create a consensus-based output has, for the most part, minimized defections from the negotiations and facilitated stakeholder buy-in.

In general, marine mammal take reduction planning is a good negotiated rulemaking process, but has produced mixed results (Chapters 1 and 2). Successful plans were characterized by straightforward regulations and high rates of compliance. Unsuccessful plans had low compliance with complex regulations and sometimes focused on very small stocks. Large teams and those in the northeastern U.S. (Maine to North Carolina) were least successful at reducing bycatch, which was reflected in stakeholder views of the effectiveness of these teams. Take Reduction Team negotiations have not always produced practical or enforceable regulations. Implementation of take reduction regulations is critical in determining plan success and identifying effective mitigation measures, but because of a lack of monitoring, has not been characterized consistently across most teams. Additionally, elements like the "Other Special Measures Provision" in the Harbor Porpoise Take Reduction Plan have undermined the negotiation process by allowing the National Marine Fisheries Service to alter consensus-based elements without consensus from the team, which has led to hostility, mistrust, and frustration among stakeholders.

The final chapter of this dissertation provides recommendations to improve the outcomes and make them more consistent across teams. I based these recommendations on the information gathered and analyzed in the first three chapters. They are grouped into four broad categories - team membership, social capital, fairness, and plan implementation. If the National Marine Fisheries Service implements these suggestions, both perceived and actual ecological effectiveness of marine mammal Take Reduction Teams should improve, allowing these teams to fulfill their maximum potential.

An understanding of sensory ecology, how animals receive and respond to their environment, can be a powerful tool for the conservation of endangered species because it can allow us to assess the potential success of actions designed to mitigate particular threats. We have a general understanding of how sea turtles perceive and respond to certain visual, magnetic, and chemical cues, but we understand very little about how they perceive and respond to acoustic cues. This dissertation explores the acoustic ecology of sea turtles, focusing on their auditory capabilities, responses to acoustic stimuli and the implications of this knowledge for their conservation. I measured the underwater and aerial hearing sensitivities of juvenile green (Chelonia mydas), hatchling leatherback (Dermochelys coriacea), and hatchling hawksbill (Eretmochelys imbricata) sea turtles by recording auditory evoked potential responses to tonal stimuli. Green turtles detected tonal stimuli between 50 and 1,600 Hz underwater (maximum sensitivity: 200-400 Hz) and 50 and 800 Hz in air (maximum sensitivity: 300-400 Hz), leatherbacks detected tonal stimuli between 50 and 1,200 Hz underwater (maximum sensitivity: 100-400 Hz) and 50 and 1,600 Hz in air (maximum sensitivity: 50-400Hz), and hawksbills detected tonal stimuli between 50 and 1,600 Hz in both media (maximum sensitivity: 200-400 Hz). Sea turtles were more sensitive to aerial than underwater stimuli when audiograms were compared in terms of sound pressure, but they were more sensitive to underwater stimuli when audiograms were compared in terms of sound intensity. I also examined the behavioral responses of loggerhead sea turtle (Caretta caretta) to simulated low frequency acoustic deterrent devices (ADDs) and found that these turtles exhibited a mild, aversive response to these sounds. This finding indicates that low frequency tonal ADDs have the potential to warn sea turtles of the presence of fishing gear and suggest that field tests of ADDs are warranted. Finally, I conducted a comprehensive review of our knowledge of the acoustic ecology of sea turtles, examined the sources of marine anthropogenic sound sea turtles are able to detect, evaluated the potential physiological and behavioral effects of anthropogenic sound, identified data gaps, and made recommendations for future research.