Pacific Science Volume 44, Number 2, 1990

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Pacific Science is a quarterly publication devoted to the biological and physical sciences of the Pacific Region.

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    44:2 Table of Contents - Pacific Science
    (University of Hawaii Press, 1990-04)
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    Iridoteuthis iris (Cephalopoda: Sepiolidae): New Records from the Central North Pacific and First Description of the Adults
    (University of Hawaii Press, 1990-04) Harman, Robert F. ; Seki, Michael P.
    Iridoteuthis iris (Berry, 1909) was originally described from a unique specimen collected in the main Hawaiian Islands, but the holotype is no longer extant. New material was collected from the southern Emperor-northern Hawaiian Ridge seamounts, extending the known range of I. iris by about 3200 km. The new samples are described, including the first description of adults.
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    Age and Growth of the Scalloped Hammerhead, Sphyrna lewini, in Northeastern Taiwan Waters
    (University of Hawaii Press, 1990-04) Chen, C.T. ; Leu, T.C. ; Joung, S.J. ; Lo, NCH
    Age and growth of the scalloped hammerhead, Sphyrna lewini, caught mostly by longline and harpoon in northeastern Taiwan waters from December 1984 to November 1985, were determined from annulus counts from 325 individuals. Translucent and opaque zones on vertebral centra were formed twice a year, in June and December. The von Bertalanffy growth curve parameters obtained using a nonlinear regression based on age and observed length were as follows: asymptotic length (Loo) = 319.72 cm total length (TL), growth coefficient (K) = 0.249, age at zero length (to) = - 0.413 yr for females; and Loo = 320.59 cm TL, K = 0.222, to = - 0.746 yr for males. Growth was apparently fast and varied among individuals. Growth rate s for females were estimated to be 63cm for the first year, 23-50 cm/yr for years 2-5, and 3-19 cm/yr for years 6-13. Growth rates for males was 54 cm for the first year, 22-42 cm/yr for years 2-5, and 11-18 cm/yr for years 6-8. Holden's method was applied to estimate growth parameters for purposes of comparison. Estimated age at maturity was 4.lyr (210cmTL) for females and-3:8yr (198cm-TL) for males, based on the von Bertalanffy growth equation from back-calculated data. The largest female (331 cm TL) whose age was determined in this study was 14.0 yr old; the largest male (301 cm TL) was 10.6 yr old.
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    A New and Primitive Barnacle (Cirripedia: Balanomorpha) from the North Fiji Basin Abyssal Hydrothermal Field, and Its Evolutionary Implications
    (University of Hawaii Press, 1990-04) Yamaguchi, Toshiyuki ; Newman, William A.
    A new sessile barnacle, Eochionelasmus ohtai, n. gen., n. sp., has been discovered associated with an abyssal hydrothermal vent at 1990m depth in the North Fiji Basin, Southwest Pacific. The genus is distinguished from its closest and bathyal relative, Chionelasmus, in having distinct, multiple whorls of basal imbricating plates. These and other characters render it the most primitive living member of the suborder Balanomorpha. Knowledge of the organization of its shell, and of the ontogeny of the shell wall in Chionelasmus, profoundly alters our understanding of the evolution of balanomorph barnacles, and a new hypothesis is proposed. Two previously described abyssal hydrothermal barnacles also proved to represent the most primitive living members of their suborder s: Scalpellomorpha and Verrucomorpha. It may be puzzling why three such antiquated morphologies should have persisted in association with abyssal hydrothermal springs while their antecedents became extinct elsewhere. However, barnacles are noted f(or their adaptability to a wide range of habitats including rigorous environments such as estuaries, the highest intertidal, and the effluent from power plants. The notable feature here, in contrast to their conservative but distinctly different shell morphologies, is the uniquely convergent adaptation of their setose feeding mechanism to vent-related food sources.
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