Permalink : http://hdl.handle.net/2115/51114

KEYWORDS : Aglantha digitale;jellyfish;abundance;body size;geographical variation

Geographical variations in abundance and body size of the hydromedusa Aglantha digitale (O.F. Müller, 1766) were evaluated in the northern North Pacific (NP), the water around Aleutian Islands (AL), eastern Bering Sea shelf (BS) and Chukchi Sea (CH) during the summers of 2007 and 2008. Abundances of A. digitale ranged between 38 and 221 ind. m-2, and had significant inverse relationships with the proportion of mature individuals. While abundances showed large annual variability, body sizes had a common regional pattern both 2007 and 2008. Body size and minimum size of maturity A. digitale were smaller in the BS and CH than those in the NP and AL. The smaller size at maturity in the BS and CH suggests regional variations in the acquired energy budget. The rapid maturity and reproduction in the BS and CH may indicate that they utilize acquired energy to mature and reproduce from smaller body sizes, while slow maturity in the NP and AL may imply that they convert acquired energy to somatic growth first.