Linking marine predator diving behavior to local prey fields in contrasting habitats in a subarctic glacial fjord

Foraging theory predicts that animals will adjust their foraging behavior in order to maximize net energy intake and that trade-offs may exist that can influence their behavior. Although substantial advances have been made with respect to the foraging ecology of large marine predators, there is still a limited understanding of how predators respond to temporal and spatial variability in prey resources, primarily due to a lack of empirical studies that quantify foraging and diving behavior concurrently with characteristics of prey fields. Such information is important because changes in prey availability can influence the foraging success and ultimately fitness of marine predators. We assessed the diving behavior of juvenile female harbor seals (Phoca vitulina richardii) and prey fields near glacial ice and terrestrial haulout sites in Glacier Bay (58°40′N, −136°05′W), Alaska. Harbor seals captured at glacial ice sites dived deeper, had longer dive durations, lower percent bottom time, and generally traveled further to forage. The increased diving effort for seals from the glacial ice site corresponded to lower prey densities and prey at deeper depths at the glacial ice site. In contrast, seals captured at terrestrial sites dived shallower, had shorter dive durations, higher percent bottom time, and traveled shorter distances to access foraging areas with much higher prey densities at shallower depths. The increased diving effort for seals from glacial ice sites suggests that the lower relative availability of prey may be offset by other factors, such as the stability of the glacial ice as a resting platform and as a refuge from predation. We provide evidence of differences in prey accessibility for seals associated with glacial ice and terrestrial habitats and suggest that seals may balance trade-offs between the costs and benefits of using these habitats

Making Self-Regulation More than Merely Symbolic: The Critical Role of the Legal Environment

Using data from a sample of U.S. industrial facilities subject to the federal Clean Air Act from 1993 to 2003, this article theorizes and tests the conditions under which organizations’ symbolic commitments to self-regulate are particularly likely to result in improved compliance practices and outcomes. We argue that the legal environment, particularly as it is constructed by the enforcement activities of regulators, significantly influences the likelihood that organizations will effectively implement the self-regulatory commitments they symbolically adopt. We investigate how different enforcement tools can foster or undermine organizations’ normative motivations to self-regulate. We find that organizations are more likely to follow through on their commitments to self-regulate when they (and their competitors) are subject to heavy regulatory surveillance and when they adopt self-regulation in the absence of an explicit threat of sanctions. We also find that historically poor compliers are significantly less likely to follow through on their commitments to self-regulate, suggesting a substantial limitation on the use of self-regulation as a strategy for reforming struggling organizations. Taken together, these findings suggest that self-regulation can be a useful tool for leveraging the normative motivations of regulated organizations but that it cannot replace traditional deterrence-based enforcement

Adenovirus-5-Vectored P. falciparum Vaccine Expressing CSP and AMA1. Part B: Safety, Immunogenicity and Protective Efficacy of the CSP Component

Background: A protective malaria vaccine will likely need to elicit both cell-mediated and antibody responses. As adenovirus vaccine vectors induce both these responses in humans, a Phase 1/2a clinical trial was conducted to evaluate the efficacy of an adenovirus serotype 5-vectored malaria vaccine against sporozoite challenge.\ud \ud Methodology/Principal Findings: NMRC-MV-Ad-PfC is an adenovirus vector encoding the Plasmodium falciparum 3D7 circumsporozoite protein (CSP). It is one component of a two-component vaccine NMRC-M3V-Ad-PfCA consisting of one adenovector encoding CSP and one encoding apical membrane antigen-1 (AMA1) that was evaluated for safety and immunogenicity in an earlier study (see companion paper, Sedegah et al). Fourteen Ad5 seropositive or negative adults received two doses of NMRC-MV-Ad-PfC sixteen weeks apart, at 1x1010 particle units per dose. The vaccine was safe and well tolerated. All volunteers developed positive ELISpot responses by 28 days after the first immunization (geometric mean 272 spot forming cells/million[sfc/m]) that declined during the following 16 weeks and increased after the second dose to levels that in most cases were less than the initial peak (geometric mean 119 sfc/m). CD8+ predominated over CD4+ responses, as in the first clinical trial. Antibody responses were poor and like ELISpot responses increased after the second immunization but did not exceed the initial peak. Pre-existing neutralizing antibodies (NAb) to Ad5 did not affect the immunogenicity of the first dose, but the fold increase in NAb induced by the first dose was significantly associated with poorer antibody responses after the second dose, while ELISpot responses remained unaffected. When challenged by the bite of P. falciparum-infected mosquitoes, two of 11 volunteers showed a delay in the time to patency compared to infectivity controls, but no volunteers were sterilely protected.\ud \ud Significance: The NMRC-MV-Ad-PfC vaccine expressing CSP was safe and well tolerated given as two doses, but did not provide sterile protection

Corals, Canyons, and Conservation: Science Based Fisheries Management Decisions in the Eastern Bering Sea

When making science matter for conservation, marine conservation practitioners, and managers must be prepared to make the appropriate decision based on the results of the best available science used to inform it. For nearly a decade, many stakeholders encouraged the North Pacific Fishery Management Council to enact protections for deep-sea corals in several canyons in the Eastern Bering Sea slope. In 2014, at the request of the Council, the National Marine Fisheries Service, Alaska Fisheries Science Center conducted a strip-transect survey along the Eastern Bering Sea slope to validate the results of a model predicting the occurrence of deep-sea coral habitat. More than 250,000 photos were analyzed to estimate coral, sponge, and sea whip abundance, distribution, height, and vulnerability to anthropogenic damage. The results of the survey confirmed that coral habitat and occurrence was concentrated around Pribilof Canyon and the adjacent slope. The results also confirmed that the densities of corals in the Eastern Bering Sea were low, even where they occurred. After reviewing the best available scientific information, the Council concluded that there is no scientific evidence to suggest that deep-sea corals in the Eastern Bering Sea slope or canyons are at risk from commercial fisheries under the current management structure, and that special protections for deep-sea corals were not warranted

Risk Analysis of Plausible Incidental Exploitation Rates for the Pacific Sleeper Shark, a Data-Poor Species in the Gulf of Alaska

<p>Monte Carlo simulation was used to investigate the sustainability of incidental exploitation rates (<i>U</i>) for Pacific Sleeper Sharks <i>Somniosus pacificus</i> in the Gulf of Alaska (GOA) under status quo management. Monte Carlo simulations were implemented with a standard, length-based, age-structured model that was evaluated with forward projection. Given the paucity of relevant data, we investigated the sensitivity of simulation results to a range of assumptions about key model parameters by using 24 alternative model configurations, each simulated 1,000 times. The risk analysis results were most sensitive to Pacific Sleeper Shark <i>U</i>-values. The aggregate fraction of simulations ending in an overfished condition increased from 0% under the low-<i>U</i> scenario to 59% under the high-<i>U</i> scenario. Risk analysis results were also sensitive to the assumed shape of the length-based selectivity curve (asymptotic or dome shaped) but were less sensitive to the range of assumptions about other key model parameters, including maximum age and stock productivity. These results indicate that a priority for Pacific Sleeper Shark management is to reduce the uncertainty in <i>U</i>. This major uncertainty will be decreased by an observer program that is now in place to monitor the historically unobserved GOA Pacific Halibut <i>Hippoglossus stenolepis</i> fishery, which incidentally catches Pacific Sleeper Sharks.</p> <p>Received March 19, 2015; accepted December 7, 2015 Published online May 16, 2016</p