A Phenological Study on Surfperch (Ditrema temminckii) at the Eastern Coast in Suo Nada Area

周防灘東部内湾域に棲息するウミタナゴ (Ditrema temminckii) の成長と成熟の季節変化について

A Phenological Study on Surfperch (Ditrema temminckii) at the Eastern Coast in Suo Nada Area

Creators Takizawa Kei

Creators Oka Hironori

Creators Takimoto Shuhei

Creators Nakazato Ayahiro

Creators Motoyama Toru

We recorded the phenological observation on the surfperch（Ditrema temminckii）whose recruitment, development and maturing aspects on the quasi population were examined. The specimens were collected in spring tide periods from 12th January 1994 to 21st December 2010 except the duration of suspension of operation due to diking in February-May 2002. We equipped two kinds of cod hoop net. The monthly total length（TL）arrangement of all the fishes illustrated that this species recruits every May and gaining larger body size within several months, they contains developed gonads, which continue to mature until next April. We perceived them as likely to be the UNDERYEARING and introduced a formula on their growth such as, L_t = 232.6 {1-e^{-0.06471(t+4.557)}} where L_t denotes the TL size（mm）at monthly age t under the condition that t =0 in May, which approved the somatic alteration of multi generation of this species. On the other hand, CPUE（N/haul）at t was represented as, logC_t = － 0.1223t + 1.536, which demonstrated how their rather small litter size creates the sustainable population in this area.

[ISSN]0370-9361