Tagged tuna graphic by Nancy Hulbirt, SOEST Illustration.

PFRP Biology Projects

Biology and Habitat Use of Monchong (Eumegistis illustris) at Cross Seamount, Hawaii

Progress Reports: FY 2012, FY 2011, FY 2010

Background Summary

The NOAA Pacific Islands Fisheries Science Center (PIFSC) and the PFRP are collaborating on studies of monchong at Cross Seamount. Monchong is a generic local name given to two deep water pomfret species; the sickle pomfret, Taractichthys steindachneri, and the lustrous pomfret, Eumegistis illustris. The sickle pomfret is a common incidental catch in pelagic longline fisheries throughout the North Pacific. The lustrous pomfret exhibits fidelity towards deep slope or seamount habitats and are generally caught by short-line or handline. Both monchong species are valued by Hawaii seafood wholesale and processing firms who have successfully promoted it in the fresh market and restaurant trade.
These species have become an increasingly important component of local Hawaii fisheries in terms of commercial fishery landings and sales in recent years. In the case of the lustrous pomfret, most of the catch occurs at Cross Seamount, a smallish seamount 8 km in diameter at the summit located 290 km south of Honolulu. Concerns over the sustainability of current pomfret removal rates with respect to recruitment from this limiting habitat have prompted the Western Pacific Regional Fishery Management Council, in coordination with PIFSC, to launch an investigation into expanding knowledge of pomfret life history and ecology.
This monchong study will occur in conjunction with the Hawaii Tuna Tagging Project 2, a PFRP-funded project that is an integrated component of a Pacific wide tuna tagging and assessment program being implemented by the Secretariat of the Pacific Community, Pacific Tuna Tagging Project (PTTP). Tagging programs are widely recognized as important tools for understanding the population dynamics, dispersal patterns and fisheries interactions of fish populations and produce additional data inputs necessary to improve stock assessments and predictive models.


1. Characterize the vertical and geographic behavior and habitat use of monchong at Cross Seamount. Investigate diurnal, lunar and seasonal patterns in vertical behavior, and location on the seamount. Tagging of monchong will occur in conjunction with tagging of bigeye tuna, Thunnus obesus, the other commercially targeted species on this seamount.

2. Characterize the flow field of Cross Seamount to provide insight into the physical environment, and help determine if there are particular flow features in regions utilized by monchong.

3. If possible, obtain estimates of growth rates, fishing mortality (F), 'natural' mortality (M) and dispersal parameters for monchong. Since the species has not been studied before, we cannot predict if data recovery will be sufficient for this objective.

Funding for this project to be available late 2009.

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Principal Investigator

Dr. Kevin Weng
Pelagic Fisheries Research Program (PFRP)
Joint Institute for Marine & Atmospheric Research (JIMAR)
1000 Pope Road, MSB 312
Honolulu, Hawaii 96822 USA
Phone (808) 956-4109
FAX (808) 956-4104
email: kweng@hawaii.edu


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