臺灣產烏魚卵脂質研究

Studics on the Fish Roe Lipids of Mullet(Mugil Cephalus)Caught off the Coast of Taiwan

吳清熊(Ching-Shyong Wu) ； 夏筱珍(Hsiao-Jen Hsia) ； 王芳珠(Fang-Chu Wang) ； 俞蘭萍(Nan-Pin Yu)

《臺灣水產學會刊》 14卷2期 (1987/12) Pp. 46-52

https://doi.org/10.29822/JFST.198712.0004

摘要

魚探信號定量化處理及標物反射强度的精確測定是利用魚探計測系統推測魚羣量之必備條件，本報告闡述設計一錄音裝置，將魚探器受波器輸出端子之信號收錄在磁帶錄音機中，並於實驗室中重現、波封、整流爲5.5 KHz直流變動信號，獨自開發一取樣頻率爲11.1 KHz(1 sample／6.75 cm)之類比、數位轉換軟體；再經系統線路功率校正及超音波物理特性考量後，獲取生物特性因子。實測方面是以該系統對不同體形魚體之超音波反射特性作一比較實驗，其結果除顯示本計測系統是輕便有效之定量計測系統外，並獲得如下之見解：(1)魚體對超音波反射之方向性隨著魚類體形之不同而改變，測試魚種中以側扁體形之黑鯧、皮刀之方向性最爲顯著，鱙仔則較不明顯。(2)魚體正背部至側部最大反射强度之增加値隨魚體之體高與體長比率値之增加而變大。(3)同一魚體，超音波以不同角度入射時，其反射强度小之部位，其反射之幅寬較長，顯示除體形因素外，魚體各部組成對反射强度有絕對的影響。

並列摘要

In order to estimate fish abundance or biomass by acoustic techniques,it isessential to make precise measurement of fish target strength and to develop a methodfor processing the echo signal from an echosounder.This report describes a devicedesigned to record the signal from the terminal of the transducer.The analog signalwas replayed and digitized with an 11.1 KHz sampling frequency(1 sample/6.75 cm)program.A software program was then made to process the digitized data andobtain the quantification information,such as depth,echo level and pulse width ofthe echo of fish.A preliminary experiment was carried out to compare the acousticscattering characteristics of fishes with different body shape.The results demonstratedthat this system is suitable for quantification purpose.In addition,the followingresults were also concluded:(1)The directional acoustic scattering characteristics were changed with the bodyshape of the fish.The highly compressed fishes,such as Formio niger and Menemaculata,show the most dominant in directional characteristics.(2)The increase of target strength(from dorsal to maximum side target strength)will increase with the ratio of body height to body length of fish.(3)According to the measurement from an individual fish,the area reflectingthe weaker sound energy always presents the wider pulse width.This coincidenceindicates that the different body compositions of an individual fish may affect on itsreflective strength as the different body-shapes do.