Predator-induced demographic shifts in coral reef fish assemblages.

In recent years, it has become apparent that human impacts have altered community structure in coastal and marine ecosystems worldwide. Of these, fishing is one of the most pervasive, and a growing body of work suggests that fishing can have strong effects on the ecology of target species, especially top predators. However, the effects of removing top predators on lower trophic groups of prey fishes are less clear, particularly in highly diverse and trophically complex coral reef ecosystems. We examined patterns of abundance, size structure, and age-based demography through surveys and collection-based studies of five fish species from a variety of trophic levels at Kiritimati and Palmyra, two nearby atolls in the Northern Line Islands. These islands have similar biogeography and oceanography, and yet Kiritimati has ∼10,000 people with extensive local fishing while Palmyra is a US National Wildlife Refuge with no permanent human population, no fishing, and an intact predator fauna. Surveys indicated that top predators were relatively larger and more abundant at unfished Palmyra, while prey functional groups were relatively smaller but showed no clear trends in abundance as would be expected from classic trophic cascades. Through detailed analyses of focal species, we found that size and longevity of a top predator were lower at fished Kiritimati than at unfished Palmyra. Demographic patterns also shifted dramatically for 4 of 5 fish species in lower trophic groups, opposite in direction to the top predator, including decreases in average size and longevity at Palmyra relative to Kiritimati. Overall, these results suggest that fishing may alter community structure in complex and non-intuitive ways, and that indirect demographic effects should be considered more broadly in ecosystem-based management.

Local stressors reduce coral resilience to bleaching.

Coral bleaching, during which corals lose their symbiotic dinoflagellates, typically corresponds with periods of intense heat stress, and appears to be increasing in frequency and geographic extent as the climate warms. A fundamental question in coral reef ecology is whether chronic local stress reduces coral resistance and resilience from episodic stress such as bleaching, or alternatively promotes acclimatization, potentially increasing resistance and resilience. Here we show that following a major bleaching event, Montastraea faveolata coral growth rates at sites with higher local anthropogenic stressors remained suppressed for at least 8 years, while coral growth rates at sites with lower stress recovered in 2-3 years. Instead of promoting acclimatization, our data indicate that background stress reduces coral fitness and resilience to episodic events. We also suggest that reducing chronic stress through local coral reef management efforts may increase coral resilience to global climate change.

Baselines and degradation of coral reefs in the Northern Line Islands.

Effective conservation requires rigorous baselines of pristine conditions to assess the impacts of human activities and to evaluate the efficacy of management. Most coral reefs are moderately to severely degraded by local human activities such as fishing and pollution as well as global change, hence it is difficult to separate local from global effects. To this end, we surveyed coral reefs on uninhabited atolls in the northern Line Islands to provide a baseline of reef community structure, and on increasingly populated atolls to document changes associated with human activities. We found that top predators and reef-building organisms dominated unpopulated Kingman and Palmyra, while small planktivorous fishes and fleshy algae dominated the populated atolls of Tabuaeran and Kiritimati. Sharks and other top predators overwhelmed the fish assemblages on Kingman and Palmyra so that the biomass pyramid was inverted (top-heavy). In contrast, the biomass pyramid at Tabuaeran and Kiritimati exhibited the typical bottom-heavy pattern. Reefs without people exhibited less coral disease and greater coral recruitment relative to more inhabited reefs. Thus, protection from overfishing and pollution appears to increase the resilience of reef ecosystems to the effects of global warming.

Strategies for identifying hereditary nonpolyposis colon cancer.

Hereditary nonpolyposis colorectal cancer (HNPCC) is the term given to a predisposition syndrome caused by inherited mutations in one of at least five DNA mismatch repair (MMR) genes. Dominant mutations in these genes predispose individuals to a range of cancers in addition to the most frequent, colorectal cancer. Endometrial cancer is the most notable additional malignancy, followed by ovarian, gastric, upper urethelial, and biliary cancers, and gliomas. Recognition of HNPCC is important so that targeted screening can be effected that will reduce the incidence of the main cancers. While such clinical criteria as Amsterdam and modified Amsterdam are reasonably specific, they lack sensitivity. Thus, tumor-related features have been used to improve sensitivity for identifying patients who can be selected for the relatively expensive direct mutation analysis of the various genes. Microsatellite instability (MSI) and loss of antibody staining for the proteins have been widely vaunted but have their own drawbacks. No one approach has received universal acceptance, and therefore adoption of one of perhaps three strategies, including clinical- and laboratory-based approaches, is still appropriate until an easier, quicker, and cheaper approach can be developed.

Evaluation of distance learning for health education.

The Hawai'i Unified Telehealth program is a distance learning health education program for rural communities, created with federal grant funding from the U.S. Department of Commerce and the National Institutes of Health. These grant funds helped develop a network of rural community learning centers that employ distance learning technologies to provide community-driven peer education to isolated areas across Hawai'i and Majuro, Republic of the Marshall Islands. In this article, the authors briefly describe the development of the ongoing health education program and the results of outcome evaluation completed at the end of the funding period.

Periodic limb movement disorder: an unusual mechanism of twiddling and potential benefit from cardiac resynchronization therapy.

Dislodgement of an LV lead is attributed to periodic limb movement disorder. Resynchronization therapy improves CHF and symptoms of periodic limb movement disorder. Potential interaction of disordered sleep and CHF in this case is briefly reviewed.