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OBSERVATIONS OF THE MESOPELAGIC MICRONEKTON BOUNDARY COMMUNITY’S DIEL MIGRATION AT OAHU, HAWAII BASED ON BACKSCATTER DATA

The mesopelagic boundary community of the Hawaiian Islands consists of micronektonic fishes, squids, and shrimps that exhibit diel migration, spending daylight hours at depth (> 400 m) to avoid predators and swimming up along the island slopes to forage during the night in shallow waters (< 100 m). Acoustic Doppler current profilers (ADCPs) deployed at deep and shallow sites off the southern coast of Oahu, Hawaii were used to estimate backscatter. Diel changes in backscatter at the sites were attributed, at least in part, to the diel migration of the mesopelagic micronekton community, offering an estimate of the timing of the migrations which could then be compared to various environmental conditions that may affect this timing. Generalized additive models (GAMs) indicated sunset time and lunar illumination were significant factors in the timing of the evening migration. The diel movement of this community along the Oahu slope links the coastal photic zone with the deep slope mesophotic zone via carbon cycling, with micronketon consuming carbon in the photic zone and respiring in the deeper slope region. While these micronekton have a vertical migration, the primary component of the migration is actually horizontal along the slopes of the island, which increases the energy budget for the mesopelagic boundary community migration relative to diel migrations in the pelagic. Given coastal development near these sites, such as a planned seawater air-conditioning system, understanding the migration of this intermediate trophic level community can help assess possible impacts of human development on local ecology.

Authors

Comfort, C. M., University of Hawaii at Manoa, USA, ccomfort@hawaii.edu

Smith, K. A., University of Hawaii at Manoa, USA, kasmith6@hawaii.edu

Sevadjian, J. C., Monterey Bay Aquarium Research Institute, USA, jsevadjian@mbari.org

McManus, M. A., University of Hawaii at Manoa, USA, mamc@hawaii.edu

Neuheimer, A. B., University of Hawaii at Manoa, USA, abneuheimer@gmail.com

Ostrander, C. E., University of Hawaii at Manoa, USA, chriso@hawaii.edu

Details

Poster presentation

Session #:018
Date: 03/01/2017
Time: 11:00 - 12:00
Location: Poster/Exhibit Hall

Presentation is given by student: No

PosterID: 203