Studies on age and growth of the dolphinfish(coryphaena hippurus) in the waters off eastern Taiwan
Date Issued
2006
Date
2006
Author(s)
Chang, Yi-Fang
DOI
zh-TW
Abstract
The age and growth of the dolphinfish, Coryphaena hippurus, in waters off eastern Taiwan was studied from the counts of growth increments on the otoliths. Specimens of otoliths were collected from a total of 215 dolphinfish ranging from 24 to 74.4 cm fork length (or 115 to 4,200 grams in body weight) landed at the ShinKang Fish Market of Taitung (eastern Taiwan) during the periods from February to July 2004 and from January to February 2005. Of which, 58 specimens ranging from 28.3 to 74.4 fork length were aged successfully. The average percent error of the ring reading was 1.6%. There was no significant difference in length-weight relationship between the female and male dolphinfish. An equation of W=7.0×10-6FL3.09 was obtained from the sex-combined length-weight data of 202 dolphinfish. Linear relationships between fork lengths and the daily growth increments were used to estimate the growth rates for the dolphinfish in the size ranges of this study. Significant difference in growth rate was found between female and male dolphinfish, and the males grew faster than the females. The growth rates were 12.5 and 8.9 cm fork length per month, respectively, for the males and the females, which were lower compared to those in Caribbean Sea and Hawaii, but higher than those in Mediterranean Sea. The distribution of back-calculated dates supports that the spawning of dolphinfish takes place year around in waters off eastern Taiwan.
Subjects
鬼頭刀
耳石
年齡成長
dolphinfish
otolith
age and growth
eastern Taiwan
Type
thesis
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