Deep-Sea FIsheries
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Map of the main Hawaiian Islands with Bottom Restricted Fishing Areas (BRFAs) indicated with orange/brown diagonal stripes





Ehu - Etelis carbunculus
Hapu'upu'u - Epinephelus quernus
Lehi - Aphareus rutilans
Opakapaka - Pristipomoides filamentosus
Kalekale - Pristipomoides sieboldii
Onaga - Etelis coruscans
Gindai - Pristipomoides zonatus

Hawaiian "Deep 7" Bottomfish images from the BotCam





BotCam equipment and deployment





Click above to visit the DAR website

Oyafuso, Z.S., Drazen, J.C., Moore, C.H., Franklin, E.C. (2017). Habitat-Based Species Distribution Models of Hawaiian Deep-Slope Fishes. Fisheries Research 195: 19-27 pdf


Sackett D, Kelley CD, Drazen JC (2017) Spilling over deepwater boundaries; evidence of spillover from two deepwater protected areas in Hawaii. Marine Ecology Progress Series 568: 175-190 pdf


Friedlander AM, Stamoulis KA, Kittinger, JN, Drazen JC, Tissot BN (2014) Understanding the scale of marine protection in Hawai'i: from community-based management to the remote northwestern Hawaiian Islands. Advances in Marine Biology 69:153-203.  pdf


Sackett DK, Drazen JC, Moriwake VN, Kelley CD, Schumacher BD, Misa WFXE (2014) Marine protected areas for deepwater fish populations: an evaluation of their effects in Hawaii. Marine Biology 161:411-425   pdf


Misa WFXE, Drazen JC, Kelley CD, Moriwake VN (2013) Establishing species-habitat associations for 4 eteline snappers with the use of a baited stereo-video camera system. Fishery Bulletin 111:293-308  pdf


Moore CH, Drazen JC, Kelley CD, Misa WFXE (2013) Deepwater marine protected areas of the main Hawaiian Islands: establishing baselines for commercially valuable bottomfish populations. Marine Ecology Progress Series 476: 167-183   pdf


Sackett D, Drazen J, Vaz A, Moore C (2012) Bottomfish Restricted Fishing Areas and the deep 7: a report of current monitoring results. Bottomfish News 14: 2-3   pdf


Merritt D, Donovan MK, Kelley C, Waterhouse L, Parke M, Wong K, Drazen JC (2011) BotCam: a baited camera system for nonextractive monitoring of bottomfish species. Fishery Bulletin 109: 56-67   pdf


Drazen JC, Moriwake V, Demarke C, Alexander B, Misa W, Yeh J (2010) Assessing Kaho‘olawe Island Reserve's bottomfish populations: a potential benchmark for main Hawaiian Island restricted fishing areas. prepared for the Kahoolawe Island Reserve Commission



This project was funded by the State of Hawaii Department of Land and Natural Resources - Division of Aquatic Resources and in part by

                                                                   the Federal Aid in Sport Fish Restoration Program.

In addition to work on the energetics of deep-sea fishes, our group has also been involved in research to inform management about Hawaii’s deep water bottom fishery.  This fishery operates from 100-400 meters (shallow compared to many other deep-sea fisheries) and harvests principally six eteline snappers and an endemic species of grouper.  Together they are called the Deep 7. These fishes, which aren’t often considered “deep” by many scientists, represent an ecologically important resource that is exploited both commercially and recreationally.   Unfortunately, as is the case with most fisheries, the main Hawaiian Islands (MHI) bottom fishery was over-exploited.  In 1997 the state’s Department of Aquatic Resources (DAR) implemented a bottomfish management plan that created 19 bottomfish restricted fishing areas (BRFAs) where bottomfishing was prohibited.  This system was reviewed and found inadequate in 2005.  In 2007, a new BRFA system was developed which took advantage of a greater knowledge of the distribution of MHI bottomfish habitat.  The new management system implemented 12 BRFAs which were selected to both protect selected habitat and to facilitate the recovery of exploited stocks.


Fisheries biologists at DAR and NOAA’s Pacific Island Fisheries Science Center have emphasized the importance of maintaining baseline and monitoring data on fisheries stocks to assess the efficacy of the new BRFA system.  The goal of our project was to monitor the bottomfish populations within a representative subset of six BRFAs over a five-year time period to assess the population impacts of the restricted fishing regulations.  We monitored the BRFAs by deploying baited bottom cameras (BotCams) at randomly selected locations within and outside of the BRFAs in depths of 100-300 meters.  The BotCams use only the ambient light and record ~ 45 minutes of activity using a pair of cameras so stereoscopic imagery is available for fish measurements. 


From 2007 to 2015, BotCams were deployed in and around seven of the 12 BRFAs as well as inside the boundaries of the Kahoʻolawe Island Reserve. In the four BRFAs monitored extensively between 2007 and 2012, mean fish length, and in some cases abundance, increased for one or more of the most economically important target species (onaga, opakapaka, and ehu) inside nearly all BRFAs, but declined or stayed the same outside. These changes over time suggest protection had an effect on the bottomfish population. Results from continued monitoring of two of these BRFAs (Penguin Bank, south of Oahu and Molokai, and Makapuʻu, off east Oahu) suggested that Deep 7 species inside these reserves likely were spilling over the boundary of the BRFAs into neighboring fished areas in the fifth and sixth years of sampling. An increasing number of trends over the years show relative abundance, fish size, and species richness (number of Deep 7 species observed in a deployment) declined with distance from BRFA; the BRFAs may have been a source of more and larger fish in later years. In the eighth sampling year, many of the significant spatial trends at the Penguin Bank BRFA disappeared. This was coincident with the State making statements about opening the BRFAs and it appears that fishing resumed in this area.  Our result may indicate that the benefits of these areas can dissolve relatively quickly when left unprotected.



In addition to the fishery-independent assessment of Deep 7 species, our research resulted in a greater understanding of species-specific habitat preferences and how those preferences may change over the lifespan of the species. This information is valuable for making informed management decisions and can help in the refinement of essential fish habitat designations and BRFA design and placement. See the references below for more detailed information on the results of our studies.


Deep-sea fisheries, those that occur for species that predominantly live below approximately 400m (Watling et al 2020), actually began in the Hawaiian Islands.  Fisheries for pelagic armorhead on seamounts far to northwest of the island chain developed in the late 1960s.  Since that time, deep-sea fisheries have expanded globally on seamounts and continental slopes to depths of ~2000 meters.  Most of these fisheries have proven to be unsustainable at high industrial harvest levels.  It’s now understood that the pace of life, including metabolism, growth and reproduction largely slows down the deeper the fish lives (see Ecological Energetics for our work in this area).  Deep-sea fish populations simply don’t have the production capacity that many shallower water species have. Additionally, considerable ecological damage has occurred from deep-sea trawling, particularly to vulnerable coral and sponge communities.


Click here to watch a video of research results aired on the DLNR Revealed Series

Last updated 9/1/23