Research Expedition to Conduct Soft-bottom and Midwater Ecosystem Surveys in the Northern Mariana Islands

June 11, 2015
Figure 1. Seen in the background, the NOAA Ship Oscar Elton Sette is named for Dr. Oscar Elton Sette, a fishery 
        oceanographer who was the founding Director of the Honolulu Laboratory, which has since become the Pacific Islands Fisheries Science 
        Center.
Figure 1. Seen in the background, the NOAA Ship Oscar Elton Sette is named for Dr. Oscar Elton Sette, a fishery oceanographer who was the founding Director of the Honolulu Laboratory, which has since become the Pacific Islands Fisheries Science Center.

On June 11, 2015, a research team under the leadership of Dr. Donald R. Kobayashi, from the NOAA Pacific Islands Fisheries Science Center (PIFSC) Ecosystem Sciences Division, departed Saipan aboard the NOAA Ship Oscar Elton Sette (Figure 1) to conduct research operations in the waters around the Northern Mariana Islands (Figure 2).

During this 17-day multidisciplinary mission, a team of PIFSC scientists in collaboration with colleagues from the NOAA NMFS Office of Science and Technology, the Joint Institute for Marine and Atmospheric Research at the University of Hawaii at Manoa, University of Hawaii at Manoa Marine Biology Program, Hawaii Pacific University, University of Guam, Northern Marianas College, American Museum of Natural History, and Micronesian Environmental Services, will be working on two principal objectives and several ancillary projects. The principal objectives share a common theme of furthering our understanding of two understudied ecosystems with a rigorous field survey approach. This descriptive characterization is extremely important from biodiversity and biogeography perspectives.

The first principal objective will be to survey soft-bottom ecosystems in the region with special reference to the distribution and abundance of the brachyuran crab species Ranina ranina. This crab, known as the red frog crab, spanner crab, or Kona crab, is widely distributed across the Pacific and Indian Oceans in sandy-bottom habitats. It is an edible crab that generally supports sustainable, small-scale fisheries where it is found in abundance. Considering the depth and remoteness of some of the soft-bottom areas in the Marianas Archipelago, there is lack of information on this species yet strong local science partner interest in better understanding the potential distribution and abundance of this species in the area. Such a project was put forth at the "Marianas Trench Marine National Monument and Mariana Archipelago Ecosystem Science Implementation Plan Workshop" that was held in Saipan in May of 2013, and was subsequently chosen by the PIFSC to complete using a research team from the NOAA ship Oscar Elton Sette. The project was originally slated for 2014 but had to be postponed to 2015 due to scheduling delays. The soft-bottom survey will be undertaken by both small-boat and ship platforms using a variety of trapping gear and optical gear. A spatially-balanced, randomized-point survey design taking into account several disparate sources of habitat data was developed using an algorithm called RRQRR (Reverse Randomized Quadrant-Recursive Raster) in Arc-GIS by PIFSC GIS staff.

The second principal objective will be to survey midwater ecosystems in the regions with a Cobb-Stauffer, dual warp, midwater trawl towed from the ship. The midwater trawl catch will be used for several different project components including studies of oceanographic connectivity, productivity and forage availability, and development of a midwater species checklist for the region. The midwater fish and invertebrate assemblage is not well characterized in the region and this survey will be very useful towards formal description of the micronekton community in the Mariana Archipelago. Latitudinal patterns in trophic relationships will be addressed by using stable isotope analysis on selected portions of the trawl catch.

Ancillary projects include genetic sampling from trapping and trawling catch to assist in the "Barcode of Life" project, biosampling of commercially important demersal and pelagic species for needed life history data, plankton net surveys of microplastic/microbead distributions, conductivity-temperature-depth (CTD) casts to understand mixed-layer ocean dynamics, and dipnetting/nightlighting operations for sampling epipelagic organisms.

Figure 2. Operational area in the Northern Mariana Islands where soft-bottom and midwater ecosystem research will be conducted.
Figure 2. Operational area in the Northern Mariana Islands where soft-bottom and midwater ecosystem research will be conducted.