臺灣海峽南部產短吻花桿狗母之年齡，成長與年齡組成估計之研究

Abstract

本報告以脊椎骨輪紋判讀法，估計臺灣海峽南部產短吻花桿狗母(Trachinocephalus myops)之年齡與成長，以Walford-plot法估算von Bertalanffy體長成長方程式，並以年齡一體長檢索反覆運演算法(IALK)估計年齡組成，其結果如下： (1)脊椎骨形質呈現：(a)體長愈大，輪紋數愈多；(b)同一尾魚各脊椎骨上各輪紋相對位置大略一致；(c)等輪紋數不同魚體之各輪紋相對位置也大略一致；(d)相鄰輪紋徑組成彼此相離，且平均輪紋徑均有差異。綜合以上結果顯示脊椎骨為一有效之年齡形質。 (2)雌、雄魚之尾叉長(L; cm)對脊椎骨椎徑(R; 1/15mm)之直線迴歸關係式，雌、雄魚間有顯著差異。其關係式分別為： 雄魚：L=2.4166+l.0439R 雌魚：L=2.7459+l.0369R (3)雌、雄魚von Bertalanffy體長(cm)成長方程式分別為 雄魚Lt=54.77[1-exp[-0.1113(t+2.5909)]] 雌魚Lt=65.38[1-exp[-0.0865(t+2.8151)]] (4)雌、雄魚取自然對數值之體重(W; g)與尾叉長(L; cm)之直線迴歸關係式，顯示雌、雄魚間有顯著差異，其關係式分別為： 雄魚：W＝6.5226×10(-3次方)L(3.1673次方) 雌魚：W＝ 7.7677×10(-3次方)L(3.1673次方) (5)脊椎骨之輪紋一年形成一輪，形成時期大約在3月至5月間。 (6)雄魚生殖盛期約在2-4月與8-11月，而雌魚之生殖盛期約在3-4月與7-9月。 (7)根據1932尾標本魚之雌、雄魚性比為0.24，經x2檢定與0.5有極顯著差異，且隨著體長與年齡增加，性比有明顯增加之趨勢。 (8)年齡組成之估計結果顯示1994年有七個年齡群，主要漁獲年齡為2歲；1995年有七個年齡群，主要漁獲年齡為0歲；而1996年有六個年齡群，其主要漁獲年齡為1歲。

Age, growth and age composition of painted lizardfish, Trachinocephalus myops, in the southern Taiwan Strait were estimated from vertebral ring counting. The von Bertalanffy growth equations were estimated by Walford-plot method and the age composition were estimated by iterated age-length key algorithm (IALK), the results were as follows: (1)The vertebral character showed:(a)the larger the fork length, the more the ring count; (b)relative positions of ring radius in all vertebrae of the same specimen were analogous;(c)relative positions of ring radius were analogous in different specimens with same rings;(d)the frequency and mean ring radius were significantly different between neighboring ring groups. Based on above results, the present study made sure that the vertebra was an effective age character. (2)There were significant difference between sexes for the relationship between fork length (L; cm) and centrum radius (R; 1/15mm), the equations were estimated as follows: Male: L=2.4166+l.0439R Female: L=2.7489+1.0369R (3)The von Bertalanffy growth equation for fork length (cm) were estimated as follows: Male: L=54.77(1-exp [-0.1113(1+2.5909)]] Female: L=65.38(1-exp [-0.0865(1+2.8151)]] (4)There were significant difference between sexes for the relationship between natural logarithmic body weight (W; g) and natural logarithmic fork length (L; cm), the equations were estimated as follows: Male: W=6.8226x10-3L3.1673 Female: W= 7.7677x10-3L3.1364 (5)The annulus was formed once a year in the period from March to May. (6)Reproductive period of female are in March-April and July-September, and male are in February-April and August-November. (7)According to 1932 specimens, sex ratio was 0.24 which was significantly different from 0.5 by X2-test, and the difference increased with fork length or age. (8)The age composition estimations showed that there were 7 age groups in 1994, 7 age groups in 1995 and 6 age groups in 1996 respectively. The major catch group appeared at age 2 in 1994 age 0 in 1995 and age 1 in 1996.