23 research outputs found

    Fisheries and Marine Resources of Hawaii and the U.S.-associated Pacific Islands: An Introduction

    Get PDF
    The fisheries of Hawaii and other U.S.-associated islands in the Pacific Ocean are characterized by high diversity, both in the species exploited and the human cultures that exploit them. The commercial sector has undergone rapid growth in recent years, but recreational and subsistence sectors remain important. Information on these fisheries is generally not available in published form. This paper presents an overview and introduction to a volume of papers describing fisheries in the region, with the goal of making the information available to scientists and the general public. A great deal remains to be learned about the dynamics of these fisheries as well as the associated issues in biological research, fisheries management, and environmental protection

    Dynamics of temperature and chlorophyll structures above a seamount: An oceanic experiment

    Get PDF
    Three hydrographic surveys comprised of densely spaced XBT and CTD stations were conducted over Minami-kasuga Seamount, in the northwest Pacific (21°36′N, 143°38′E). A cold dome, similar to a Taylor column, was observed above the seamount top during the first survey. Uplifted isotherms penetrated to the lower euphotic zone and were associated with higher chlorophyll concentrations. Vertical displacement of uplifted isotherms decayed with elevation above the seamount, so that both temperature and chlorophyll anomalies were undetectable at depths less than 80 m. Relatively high chlorophyll concentrations in a layer from 80 m to 100m depth formed a distinctive deep chlorophyll maximum (DCM) which was less well defined away from the seamount. Calculations based on the observed chlorophyll increase and on estimated phytoplankton growth rate suggested a minimal residence time of the cold dome on the order of several days. Zooplankton densities were also higher over the seamount top, both within and above the cold dome. No cold dome, chlorophyll increase, or high zooplankton biomass were detected above the seamount on the second and third surveys, carried out 2 and 17 days later, respectively. Mixing and deflections of isotherms occurred within a boundary zone around the seamount slope during the first and third surveys.Our observations suggest that seamounts are a source of both biological and physical patchiness in the surrounding ocean as features developed above them are swept away. The importance of the seamount-generated experiment is discussed in relation to field studies of the DCM. Specifically, our observations suggest that a sharp chlorophyll maximum can be formed by enhanced in situ growth following a sub-surface upwelling event

    Populations of the Sternoptychid Fish Maurolicus muelleri on Seamounts in the Central North Pacific

    Get PDF
    The lightfish, Maurolicus muelleri (Gmelin), is a cosmopolitan sternoptychid fish most abundant near continental shelf-slope breaks and rare in the open ocean. Recent studies have documented dense populations on seamounts of the South Atlantic and North Pacific. At Southeast Hancock Seamount, a small guyot in the central North Pacific, M. muelleri populations are mainly composed of juveniles. Seasonal length frequencies suggest that recruitment at sizes greater than 20 mm standard length (SL) occurs principally in spring and summer months, with growth over summer and fall coincident with decreasing abundances. Mature fish in reproductive condition occur in winter months but do not survive to the following spring; they also may be too few at this small seamount to support annual recruitment. Potential sources of additional recruitment include populations at several larger seamounts in the southern Emperor group and also the large populations around Japan. Advection of eggs and larvae in the Kuroshio Extension may provide recruits for dependent populations at the seamounts. Mean current flow and satellite-tracked drifters suggest a transit time of 100-200 days from the coast of Japan to the region of the seamounts; estimates of age at length suggest that smaller fish have similar ages at recruitment. Gill-raker counts, however, differ between Japanese and seamount populations. We suggest that the southern Emperor Seamount populations serve as the source for replenished annual recruitment to the small population at Southeast Hancock Seamount

    REPRODUCTION, EMBRYONIC ENERGETICS, AND THE MATERNAL-FETAL RELATIONSHIP IN THE VIVIPAROUS GENUS SEBASTES (PISCES: SCORPAENIDAE)

    No full text
    Volume: 167Start Page: 354End Page: 37
    corecore