Use of multivariate control charts to assess the status of reef fish assemblages in the Northwestern Hawaiian Islands (original) (raw)
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Diversity, 2020
The architectural complexity of coral-reef habitat plays an important role in determining the assemblage structure of reef fish. We investigated associations between the reef habitats and fish assemblages in the Northwestern Hawaiian Islands (NWHI) using in situ fish counts and data on habitat metrics and benthic community composition that were obtained from three-dimensional (3D) photogrammetric reconstructions of the surveyed sites. The structure of fish assemblage as a whole on the basis of Bray-Curtis dissimilarity, species richness and the abundances of herbivores and piscivores were associated with habitat metrics, with higher levels of architectural complexity generally supporting greater numbers of fish species and individuals. Benthic cover did not explain additional variation in these variables after the effects of habitat metrics were taken into account. Corallivorous fish was the only group that showed positive associations with both habitat metrics and benthic cover (Acropora and Pocillopora corals). The total fish abundance and the abundances of planktivores and invertivores did not show associations with either habitat metrics or benthic cover. This study suggests that an appropriate combination of habitat metrics can be used to account sufficiently for the effects of habitat architecture on fish assemblages in reef monitoring efforts in the NWHI.
Coral Reefs, 2003
The relationships between fish assemblages, their associated habitat, and degree of protection from fishing were evaluated over a broad spatial scale throughout the main Hawaiian islands. Most fish assemblage characteristics showed positive responses to protection whether it was physical (e.g. habitat complexity), biological (e.g. coral cover growth forms), or human-induced (e.g. marine reserves). Fish biomass was lowest in areas of direct wave exposure and highest in areas partially sheltered from swells. Higher values for fish species richness, number of individuals, biomass, and diversity were observed in locations with higher substrate complexity. Areas completely protected from fishing had distinct fish assemblages with higher standing stock and diversity than areas where fishing was permitted or areas that were partially protected from fishing. Locations influenced by customary stewardship harbored fish biomass that was equal to or greater than that of no-take protected areas. Marine protected areas in the main Hawaiian islands with high habitat complexity, moderate wave disturbance, a high percentage of branching and/or lobate coral coupled with legal protection from fishing pressure had higher values for most fish assemblage characteristics.
Marine Ecology Progress Series, 2007
Over the past 4 decades, Hawaii has developed a system of Marine Life Conservation Districts (MLCDs) to conserve and replenish marine resources. These MLCDs vary in size, habitat quality, and management regimes, providing an excellent opportunity to test hypotheses concerning marine protected area (MPA) design and function using multiple discreet sampling units. Digital benthic habitat maps for all MLCDs and adjacent habitats were used to evaluate the efficacy of existing MLCDs and adjacent habitats using a spatially explicit stratified random sampling design. Most fish assemblage characteristics (e.g. species richness, biomass, number of individuals) were highest in colonized hard bottom habitats (>10% live coral cover), followed by uncolonized hard bottom habitats (<10% live coral cover), macroalgae, and sand, respectively. Although biomass was low in sand habitats, apex predators accounted for 62% of the biomass on sand within MLCDs, highlighting the importance of this habitat in reserve design. Within habitats, values for assemblage characteristics were typically higher for MLCDs compared with adjacent areas, emphasizing the importance of protection from fishing irrespective of habitat. Rugosity explained much of the variability in species richness and biomass across all locations. Overall, MLCDs protected from fishing, with high habitat complexity and good habitat quality (e.g. high coral cover and low macroalgae cover), had higher values for most fish assemblage characteristics. Integrating mapping and assessment of reef fish habitat utilization patterns allowed for a robust approach to MPA evaluation and can help inform decisions about MPA design and effectiveness, as well as helping to define essential fish habitat and ecosystem function.
Bulletin of Marine Science Miami, 1996
Reef fish faunas were compared between surveys conducted more than a decade apart at each of two isolated and nearly pristine oceanic atolls (French Frigate Shoals [FFS] and Midway Atoll) in the northwestern Hawaiian Islands, Species composition, assemblage struc ture (density rankings), and population densities were compared to test the hypothesis that reef fishes had declined during a period of lower oceanic productivity in the central North Pacific. Within each of two principal habitats (barrier and patch reefs) at each atoll, species composition and rank densities differed little between sampling periods. Densities, howcver, generally declined by about one-third for many numerically dominant species and for taxa pooled into functional categories (trophic levels. feeding guilds). Patterns of temporal change were partly confounded by distributional shifts between barrier and patch reef habitats at "1'S, perhaps reflecting indirect effects of stonn disturbance on benthic algal habitat. Such effeets, together with related changes in climate and oceanic productivity on an interdecadal time scale, might have been responsible for the apparent declines in reef fish densities at both atolls. Temporal patterns were clearer at Midway Atoll, where changes in benthic algae were not evident. Our observations indicate that the statistical power necessary to detect changes in the population densities of reef fish species that exhibit large temporal fluctuations in numbers, particularly on oceanic islands, is generally low. Power to detect twofold changes may be adequate, however, if taxa are pooled into functional categories.
Habitat characteristics affecting fish assemblages on a Hawaiian coral reef
Journal of Experimental Marine Biology and Ecology, 1998
Habitat characteristics of a reef were examined as potential influences on fish assemblage structure, using underwater visual census to estimate numbers and biomass of all fishes visible on 42 benthic transects and making quantitative measurements of 13 variables of the corresponding physical habitat and sessile biota. Fish assemblages in the diverse set of benthic habitats were grouped by detrended correspondence analysis, and associated with six major habitat types. Statistical differences were shown between a number of these habitat types for various ensemble variables of the fish assemblages. Overall, both for complete assemblages and for component major trophic and mobility guilds, these variables tended to have higher values where reef substratum was more structurally or topographically complex, and closer to reef edges. When study sites were separately divided into five depth strata, the deeper strata tended to have statistically higher values of ensemble variables for the fish assemblages. Patterns with depth varied among the various trophic and mobility guilds. Multiple linear regression models indicated that for the complete assemblages and for most trophic and mobility guilds, a large part of the variability for most ensemble variables was explained by measures of holes in the substratum, with important contributions from measured substratum rugosity and depth. A strong linear relationship found by regression of mean fish length on mean volume of holes in the reef surface emphasized the importance of shelter for fish assemblages. Results of this study may have practical applications in designing reserve areas as well as theoretical value in helping to explain the organization of reef fish assemblages.
2003
INTRODUCTION NOAA’s National Centers for Coastal Ocean Science (NCCOS) Biogeography Program conducts mapping, research, and monitoring of tropical coral reef ecosystems to support wise management of coastal marine resources (Monaco et al. 2001). A biogeographic approach is utilized to integrate information on the distribution and quality of habitats and associated reef fish to define species affinities for specific habitats (Monaco et al. 2001, Kendall and Monaco 2002). Defining the strength of coupling between species and habitat is facilitated by integrating spatial statistics, ecological models and indices that are visualized in geographical information systems (GIS) (Monaco et al. 1998, Gill et al. 2001). The biogeographic approach enables implementation of a suite of reef fish ecology studies (RFES) that are underway in the US Caribbean and the main eight Hawaiian Islands (MHI). High-resolution digital benthic habitat maps derived from aerial photography and hyperspectral image...
Over a Decade of Change in Spatial and Temporal Dynamics of Hawaiian Coral Reef Communities
Pacific Science, 2015
The Hawai'i Coral Reef Assessment and Monitoring Program (CRAMP) was estab lished in 1999 to test the hypothesis that reef condition is related to anthropogenic and natural forcing functions and that manage ment practices (various levels of protection) can conserve and restore coral reefs through regulating human impact (Brown et al. 2004). Management needs were addressed to de velop a baseline and understand the current status and future stability of Hawaiian reefs (http://cramp.wcc.hawaii.edu). No statewide