Classification of Schooling Structures of Engraulis Japonica by Processing the Hydroacoustic Signal and Discriminant Analysis

Abstract

為探討花身鷄魚(Terapon jarbua)由稚魚(juvenile)發育為幼魚(young)是否對胺基酸有不同之行為反應，本實驗乃利用全體長5.8±0.8公分（n=30）之野生花身鷄魚之幼魚，進行行為反應之分析，並與其稚魚相比較。實驗時選用8種水產生物體常見之游離胺基酸，製成0.01 M之洋菜塊隨機固定於實驗水槽（70×50×45公分），以攝影機（JVC,TK-S300U）及縮時錄影機（time-elapse recorder,JVCBR-9050U）記錄，並分析60分鐘內，各洋菜塊被攝食之重量。實驗結果先以ANOVA(Analysisof Variance)檢定胺基酸種類及胺基酸位置對稚魚及幼魚之攝食次數及攝食重量之影響；再以Scheffe'多重比較試驗(Multiple Comparison Test)進一步比較含胺基酸之各洋菜塊與純洋菜塊被攝食重量之差異。實驗結果顯示，八種測試胺基酸被攝食重量之多寡依序為alanine，cysteine，glycine，asparticacid，proline，glutamic acid，lysine，arginine均比對照組之純洋菜塊為高。Two wayANOVA統計分析，結果顯示「位置」因子並無顯著差異（F=0.93），而胺基酸「種類」則有顯著效應（F=22.73）；因此，洋菜塊被消耗重量之差異是其所含胺基酸之種類所致。經Scheffe'多重比較檢定八種胺基酸及純洋菜塊間差異是否顯著，結果顯示幼魚與稚魚除所嗜好之胺基酸次序不同外，並對胺基酸間有較多之分辨能力（幼魚之差異區分6組，稚魚只區分2組）。因此，花身鷄魚之幼魚對不同胺基酸之嗜食程度與其稚魚不同，且顯示此一階段之魚體有較佳之味覺能力，以辨別食物種類；兩階段均以alanine為顯著較高之攝食胺基酸，卽其天然餌料中，可能均含有較高含量之alanine。In order to investigate the behavioural shifts of young thornfish(Teraponjarbua)to some amino acids,30 wild young thornfish(5.8±0.8 cm)were usedfor studying the preference for these amino acids.L-form 0.01 M alanine,arginine,aspartic acid,glutamic acid,glycine,cysteine,lysine and proline weredissolved in agar blocks(pure agar was used as a control),which were laterrandomly hanged in experimental tanks in each treatment.Monitoring andrecording were made by a set of video recording system.Pecking numbersand consumption weights of each block were measured.The order of the consumption weights for the amino acids is alanine＞cysteine＞glycine＞aspartic acid＞proline＞glutamic acid＞lysine＞arginine.Two way ANOVA indicates the existence of differences of pecking frequenciesand consumption weights among amino acids(F=22.73,p＜0.01),but not amongthe locations(F=0.93);Scheffes'Multiple Comparison Test further reveals thatalanine is significantly preferred and pure agar is the least by the thronfishof this stage.No significant difference can be found between the pure agarand the three least preferred amino acids.The ontogenetic changes of the behavioural response to amino acids injuveniles developing to youngs were found in the present study.Youngsdemonstrated a better discrimination ability for amino acids and alanine istheir common favourite.