CRED Towed-Diver Fish Biomass Surveys in the Pacific Ocean 2000-2010

Abstract written by OBIS-USA using excerpts from CRED Homepage

Quantitative assessment and monitoring of shallow reef fish assemblages is conducted around the US Pacific Islands as an integral part of the NOAA/NMFS/PIFSC Coral Reef Ecosystem Division's mission to improve our scientific understanding of these fish resources and related ecosystems. As fish are the primary sustainable living resource on Pacific coral reefs, results contribute to the scientific basis essential for sound management. Related objectives include: creating a fish baseline to measure marine protected area (MPA) effectiveness; monitoring size-frequency of fish assemblages; assessing the status of target, indicator or keystone species; assessing responses by fish communities to possible ecosystem impacts (e.g., fishing, ecotourism, pollution, habitat damage, sedimentation, hurricanes); and assessing species composition and diversity, by area, and the effectiveness of long-term monitoring of managed areas.

Several complementary, noninvasive underwater-surveys are used to enumerate the diverse components of diurnally active shallow-water reef fish assemblages. Survey types include:

(1) Rapid Ecological Assessments (REA) to document simple species presence at a station or reef/bank

(2) Belt Transects (BLT) mainly to quantify relatively small-bodied and abundant fishes

(3) Stationary Point Counts (SPC) to quantify relatively larger (>25 cm total length) and more vagile fish species

(4) Towed-Diver Video Surveys (TDVS) to quantify relatively large-bodied (>50 cm total length), wide-ranging fishes over a broad-spatial scale

Each method is replicated at sites within and/or among the various habitat types present around each island or bank. Fish length-class is estimated for all quantified fish to provide an estimate of numerical size structure and biomass densities by taxa.