ISSN:
1573-5133
Keywords:
Diet composition
;
Feeding periodicity
;
Field data
;
Daily consumption
;
Fish
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Synopsis The unusual life history of pelagic armorhead, Pseudopentaceros wheeleri, includes occupation of epipelagic subarctic and transitional waters of the northeast Pacific Ocean and Gulf of Alaska as subadults and subsequent recruitment to the southern Emperor and northern Hawaiian Ridge (SE-NHR) seamounts in the central North Pacific Ocean where they assume a demersal existence and begin maturation as adults. Feeding ecology and daily ration were examined in pelagic armorhead during field studies conducted at Southeast Hancock Seamont (29°48′ N,179°04′ E) in the SE-NHR seamounts. A total of 1133 stomachs collected during June-July 1985, January 1988, and July 1988 were examined for contents; only 19.7% contained food items. The diet consisted of pelagic tunicates and other micronektonic animals that are associated with the vertically migrating sonic scattering layer that is advected over the seamount from the adjacent oceanic environment. Peak feeding occurred in the early morning on migrating organisms likely trapped by the expanse of the seamount summit during the morning descent. Newly recruited armorhead had lower feeding rates than older, previously recruited fish. Estimates of daily ration for previously recruited armorhead were 1.17 g (0.26% of body weight) in the summer of 1985 and 12.87 g (2.86% of body weight) in the summer of 1988. Since estimated values for the evacuation coefficient and the duration of the daily feeding period did not differ between sampling periods, the increase in daily ration was due to an increase in feeding rate. The proportion of the diet composed of pelagic tunicates was also higher in 1988.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00004758
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