Ortiz, D. M., Tissot, B. N.

Ontogenetic variation of a coral reef fish in an MPA network in Hawaii: A multi-scale remote sensing and in-situ approach

2006

Transactions, American Geophysical Union

87 [36 Supplement]

n.p.

Several studies have highlighted the role of habitat as an important component in structuring reef fish assemblages. Understanding the scale at which habitat characteristics influence spatial abundance and distribution of reef fish is important because processes that function at small scales may be different than those at larger spatial scales. Therefore, information on benthic habitats at a range of spatial scales is critical to the understanding and prediction of spatial distributions and abundances of reef fish. Our study is aimed at using a combination of NOAA's archived remote-sensing data, LIDAR bathymetry data and in-situ geographically referenced meso-scale underwater video surveys to evaluate, map and assess fish-habitat associations and patterns throughout the different life stages of reef fish in an existing Hawaii Marine Protected Area (MPA) network on the west coast of Hawaii (West Hawaii). Five years of prior monitoring in these areas has shown that the microhabitat (1-10s m), appears to be an important resource for the survival of targeted juvenile aquarium fish. Consequently, it is imperative to evaluate ontogenetic shift in habitat use on a scale consistent with the structuring patterns of habitat used displayed by species of reef fish. To meet the first objective, meso-scale video transects (10-100s m), on both fishery replenishment areas and adjacent closed control areas off the west coast of Hawaii, were made in order to determine the scale at which the mapping of habitat use in the life history stages of reef fish occurs. ArcGIS allowed the overlay of NOAAs broad-scale benthic habitat maps with a higher resolution habitat-based assessment map spatially relevant with the patterns of habitat used by reef fish through each life stage. To meet our second objective, a stratified monitoring effort was carried out to quantify habitat use and distribution of reef fish through the life history stages of aquarium reef fish. To date we have established 91 monitoring sites at four MPAs along the west Hawai'i coastline. Our work provides a description of the spatial variation of habitat characteristics at the meso (10-100's of meters) spatial scale and reveals significant ontogenetic shifts in habitat use of aquarium fish for two of the nine FRA's. These results indicate that multiple habitats are important for the life history of aquarium fish and the distribution and abundance of these habitats may influence the effectiveness of MPAs to replenish depleted fish stocks. The use of archived remote sensed data and in-situ underwater surveys on the MPAs allowed us to quantify spatial dependencies of the life stages of reef fish not previously revealed by methods used at very fine (1-10's m) or broad spatial scales (10-100's km).

coral reef fishes /Marine parks and reserves - networks /Hawaii /remote sensing /Ontogenic Habitat Shifts

CSA Abstract