- 期刊
- OpenAccess
Estimating Catch Matrix of Indian Albacore by Iterated Age-Length Key Algorithm
以年齡—體長檢索反覆運算法估計印度洋長鰭鮪之年齡別漁獲量
摘要
在有混雜魚種棲息之水域，利用超音波迅捷評估魚羣現存量時遭遇到無法區別魚種之困擾；本研究於1988～1989年夏天，在有二（鎖管及鰺科魚種）或三（鎖管、鰺、鰹魚）混合魚種之臺灣東北角水域進行試驗，將混合魚種之聲探類比囘訊收錄在磁帶錄音機中，並在實驗室中進行聲探囘訊信號處理，將所求得之魚羣囘訊因子做為說明變數，經逐步判別分析法選出主成分之說明變數後，以典型判別分析所得之線性典型判別式，證實其同時考量有魚羣內在結構、外在結構及羣集行動等生物資訊，對混合組成魚種之區分率高達94％以上；不過，水域環境不同或組成魚種不同時，其擷取之說明變數或判別式之係數亦有差異，故需使用不同之判別式。
並列摘要
Since the application of hydroacoustic quick assessment method is unableto discriminate species within a multi-species fish community,field experimentswere carried out in the summer seasons of 1988 and 1989 at Yen-Liao Bay,northeastern corner of Taiwan,as an attempt to solve this problem.Schoolsignals from the combinations of two(squid and carangid)or three species(squid,carangid and bonito)were recorded on audio magnetic tapes.Afterward,the analog signals were digitized to obtain 14 acoustic explanatoryvariables in laboratory.The principal components correlated with bothinternal structure,shape and behavior pattern of schools were extracted bystepwise discriminant analysis.Canonical discriminant functions based onthe discriminators were obtained.The discriminanting rate of the speciestested in this study exceeds 94%.Accordingly the potential of applying the hydroacoustic signal processingand canonical discriminant analysis to fisheries acoustic will be evidenced.Furthermore,it is also indicated that the discriminators or coefficients ofdiscriminant function may vary with species,seasons and environmentalconditions.