Fishing and pollution are chronic stressors that can prolong recovery of coral reefs and contribute to ecosystem decline. While this premise is generally accepted, management interventions are complicated because the contributions from individual stressors are difficult to distinguish. The present study examined the extent to which fishing pressure and pollution predicted progress towards the Micronesia Challenge, an international conservation strategy initiated by the political leaders of 6 nations to conserve at least 30% of marine resources by 2020. The analyses were rooted in a defined measure of coral-reef-ecosystem condition, comprised of biological metrics that described functional processes on coral reefs. We report that only 42% of the major reef habitats exceeded the ecosystem-condition threshold established by the Micronesia Challenge. Fishing pressure acting alone on outer reefs, or in combination with pollution in some lagoons, best predicted both the decline and variance in ecosystem condition. High variances among ecosystem-condition scores reflected the large gaps between the best and worst reefs, and suggested that the current scores were unlikely to remain stable through time because of low redundancy. Accounting for the presence of marine protected area (MPA) networks in statistical models did little to improve the models’ predictive capabilities, suggesting limited efficacy of MPAs when grouped together across the region. Yet, localized benefits of MPAs existed and are expected to increase over time. Sensitivity analyses suggested that (i) grazing by large herbivores, (ii) high functional diversity of herbivores, and (iii) high predator biomass were most sensitive to fishing pressure, and were required for high ecosystem-condition scores. Linking comprehensive fisheries management policies with these sensitive metrics, and targeting the management of pollution, will strengthen the Micronesia Challenge and preserve ecosystem services that coral reefs provide to societies in the face of climate change.
Abstract. Coral-reef fisheries pose a problem for traditional forms of management because stock assessments and demographic data are limited in diverse systems. We used catch records coupled with fisher interviews to derive hierarchical indicators of fishery status by (1) characterizing catch-and-effort trends with respect to environmental factors, (2) assessing the degree to which biomass-and-abundance distributions were coupled across trophic levels, and (3) identifying key characteristics of species-based landings that were sensitive to fishing pressure and linked with management guidance. Using data across one year from a representative Pacific Island fishery, we show that catch and effort were constrained by environments, as both were disproportionally highest during favorable new moon phases in spring, but more effort was required to catch fewer fish later in the year, and the size of target species declined. The magnitude of constrained catch success provided an initial indication of status that could be compared spatially and temporally. Second, biomass-and-abundance distributions were examined within dominant fish families. Large-bodied species contributed most to biomass in low trophic positions, but small-bodied counterparts were more abundant, following expected observations from systems with less human influence. However, biomass-and-abundance distributions became coupled for invertivores and predators, as small species and individuals were most represented. The shape and fit of regressions between asymptotic lengths and proportional landings identified drivers of coupled distributions. Polynomial fits highlighted that smaller-bodied species were main components of the fishery, while linear fits suggested that largerbodied species were still dominant, and tolerant of current fishing pressure. Last, two indicators were used to identify management objectives for target fishes, skewness of size distributions and proportional contributions to landings. Significantly skewed size distributions existed for most target fishes, suggesting high density dependence and recruitment, and the potential for size-based polices to achieve desirable fishery objectives. Meanwhile, the diminished and constrained contribution of many large species indicated their vulnerability despite non-significant shifts in size. Catch quotas, gear limitations, or temporary restrictions may be more appropriate for sustaining these species. A framework is synthesized to interact with stakeholders and consider holistic management approaches for multispecies coral-reef fisheries.
Tropical Pacific island streams have poorly understood communities that deserve scientific attention. We examined benthic macroinvertebrates and fishes of the Inem River on Kosrae, Federated States of Micronesia. Larval chironomids, lepidopterans, odonates, and freshwater shrimps dominated the benthos and drift. Diel periodicity in drift was not evident. Nine fishes, two shrimps, and one snail species were identified. Kosrae's stream fauna appears even more depauperate than other Pacific high islands, possible due to its extreme isolation.
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