台灣東部海域齒鰆之生殖生物學研究

Reproductive biology of striped bonito, Sarda orientalis, in the waters off eastern Taiwan

黃鈞淳(Jun Chun Huang)

指導教授 ： 孫志陸

國立臺灣大學/理學院/海洋研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.00948

摘要

本研究自2013年12月至2014年11月，於宜蘭東澳灣、南方澳魚市場及台東成功新港收集沿岸定置網、扒網、曳繩釣及延繩釣漁船所捕獲之齒鰆(Sarda orientalis)，採取其生殖腺，並記錄體長、體重、生殖腺重及性別等資料，總計採得323尾(雄魚175尾; 雌魚148尾)齒鰆樣本，樣本尾叉長範圍30.8 ~ 80.2 cm，體重介於0.42 ~ 7.69 kg。利用變積分析(ANCOVA)檢定雌雄間體長體重關係式，結果顯示沒有顯著差異(p > 0.05)，因此將雌雄資料合併分析得到RW = 2.13×10-2 FL2.90 (r² = 0.92; n = 320)。總性比（雌魚尾數/雌雄總尾數）為0.46，經卡方檢定與雌雄比1 : 1沒有顯著差異，月別性比之間也沒有顯著差異(χ2 = 11.56; p = 0.31)，體長別性比的檢定結果顯示有顯著差異(χ2 = 43.4; p < 0.05)，尾叉長60 cm以上之雌魚所占的比例有隨著體長逐漸增加的趨勢。本研究根據生殖腺指數、平均卵徑與生殖腺成熟階段的月變化分析，推斷台灣東部海域齒鰆之生殖季節為每年的1到6月，以3到5月為高峰期。另外，組織切片觀察的結果顯示，齒鰆屬於分批產卵的魚種(batch spawner)，卵細胞的發育過程不同步(asynchronous)，且沒有明確的年孕卵數(indeterminate fecundity)。齒鰆50 % 成熟體長(L50)的估計結果，雌魚為尾叉長47.8，雄魚為43.8 cm; 最小性成熟體長的結果，雌魚為尾叉長44.9 cm，雄魚為尾叉長43 cm。以產卵後濾泡法估算生殖季節間有生殖活動(reproductive activity)的雌魚之產卵比例(spawning fraction)為0.43，換算產卵頻率(spawning frequency)為平均2.3天排卵一次; 雄魚藉由計算生殖季節間完熟期個體所佔之比例(0.51)，為平均2天會排精一次。以水卵法估計雌魚之單次孕卵數，結果為11.4至77.9萬顆卵粒，每公克雌魚體重所含的卵粒數介在63.2到115.3顆之間。綜合上述結果，本研究推論台灣東部海域為齒鰆的產卵海域之一，研究結果可用於系群資源評估模式之參數的基本輸入，為漁業管理提供適當且有信服力的科學參考依據。

關鍵字

性比 ； 生殖季節 ； 50 % 成熟體長 ； 產卵頻率 ； 單次孕卵數

並列摘要

The reproductive biology of striped bonito (Sarda orientalis) was assessed by examining 323 specimens sampled from the catches of set-net, troll line, longline and danish seine fisheries in the waters off eastern Taiwan during December 2013 to November 2014. Body sizes of the specimens ranged from 30.8 to 80.2 cm in fork length (FL) and 0.42 to 7.69 kg in round weight. The overall sex ratio (number of females to the total number of fish) was 0.46 which did not differ significantly from 0.5 based on the Chi-square test. The monthly sex ratios were homogeneous among months in 2014. However, the sex ratios at different length classes were significantly different, females were predominant in sizes > 60 cm FL. Gonadosomatic index (GSI), monthly variation in mean diameters of oocytes and the gonadal development stages were used to assess the reproductive activity of striped bonito. Results showed that the spawning season of striped bonito occurred from January to June, with a peak between March and May. Based on histological examination and oocyte diameter frequency distribution, striped bonito are batch spawners and the oocytes developed asynchronously. The estimated size-at-50 % maturity was 47.8 cm FL for females, and 43.8 cm FL for males. The smallest sizes for sexually mature females and males were 44.9 and 43.0 cm FL, respectively. Females and males were estimated to spawn once every 2 days on average during the spawning season. Batch fecundity estimated from six females of 49.0 to 77.9 cm FL ranged from 11.4 to 77.9 ten thousand hydrated oocytes. The estimated relative fecundity was from 63.2 to 115.3 hydrated oocytes per gram of body weight. The parameters estimated in this study are key information for stock assessment of striped bonito in the waters off eastern Taiwan, and will contribute to the conservation and sustainable yield of this species.

並列關鍵字

sex ratio ； spawning season ； size at 50 % maturity ； spawning frequency ； batch fecundity

參考文獻

王尉任，2005。西太平洋黃鰭鮪生殖生物學研究，碩士論文，國立台灣大學海洋研究所。

曾淑芳，2009。台灣東部海域竹節鰆之生殖生物學研究，碩士論文，國立台灣大學海洋研究所。

傅信欽，2004。中西太平洋與台灣東部海域正鰹之生殖生物學研究，碩士論文，國立台灣大學海洋研究所。

Alejo-Plata, C., Diaz-Jaimes, P., & Salgado-Ugarte, I. H. (2011). Sex ratios, size at sexual maturity, and spawning seasonality of dolphinfish (Coryphaena hippurus) captured in the Gulf of Tehuantepec, Mexico. Fisheries Research, 110(1), 207-216.

Ateş, C., Cengiz Deval, M., & Bök, T. (2008). Age and growth of Atlantic bonito (Sarda sarda Bloch, 1793) in the Sea of Marmara and Black Sea, Turkey. Journal of Applied Ichthyology, 24(5), 546-550.