南東海劍尖槍鎖管體型與生殖狀況之時空變化

Abstract

劍尖槍鎖管 (Uroteuthis (Photololigo) edulis) 是臺灣火誘網漁業之主要目標物種之一。本研究於2003 ~ 2008年間進行六年的標本採集，由生殖腺指數與性成熟階段組成之月別變化得知，劍尖槍鎖管在每年可能有春 (3 ~ 5月)、秋 (10 ~ 12月) 兩產卵季。東海南部 (臺灣北部水域) 依水文大致可分為三區：沿岸、湧昇流及鋒面區。由鎖管外套膜長 (mantle length, ML) 及成熟階段組成結果顯示，春、秋兩產卵期時，較多已成熟的雌、雄鎖管出現在沿岸或湧昇流海域，推測此區可能為鎖管產卵場。每年1 ~ 3月時，鎖管只出現於沿岸及湧昇流海域，其平均ML是各月份最小的，推測可能為鎖管育成場 (nursery ground)。鋒面海域常捕獲體型小且未成熟鎖管，是為索餌成長洄游的海域。Uroteuthis (Photololigo) edulis is one of the main target species of the torch-light fishery in Taiwan. The samples of U. (P.) edulis were collected from the southern East China Sea between 2003 and 2008. The monthly variations of Gonadosomatic index (GSI) and percentage of mature squid indicated that U. (P.) edulis spawned in spring (March - May) and autumn (October - December). According to hydrological characteristic of southern East China Sea (waters off north Taiwan), U. (P.) edulis mainly distributed in three areas: coastal, upwelling, and frontal areas. The composition of mantle length (ML) and sexual maturity stages showed that most mature individuals occurred in the coastal and upwelling areas during spring and autumn spawning period. It indicated that the coastal and upwelling areas were the spawning grounds. During Janruary to March, U. (P.) edulis caught in the frontal area was small and immature U. (P.) edulis and it showed that it was a feeding ground.