近年來養殖的黑鯛(Acanthopagrus schlegeli)和金目鱸(Lates calcarifer)的人工孵化魚苗經常被大量放流到台灣沿岸海域中,然而以往有關魚苗標誌試驗以及放流效果的評估卻相當稀少,推測其原因,可能是放流魚苗體型小不易逐尾進行魚體的標誌,以及數量多不易在短時間內完成標誌工作,以及洄游性魚種不易被捕獲與回報。所以選擇合適的方法標誌放流魚苗對放流效果評估工作是相當重要的。因此,本研究針對黑鯛及金目鱸兩魚種,探討幾種魚苗大量標誌方法的標誌留存率與殘存率,以找出合適的魚苗大量標誌法。試驗分別針對5公分左右的黑鯛和金目鱸魚苗採用染色法(將魚隻浸泡在含有食用色素的水溶液中)、四環黴素浸泡法(將魚隻浸泡在含有四環黴素的水溶液中)、噴槍法(利用高壓噴槍將螢光色素打在魚的表皮)與對照組進行試驗。本研究也針對金目鱸魚苗採用雙重標識法(四環黴素投餵法加上噴槍法)與對照組進行試驗。結果顯示黑鯛試驗的標誌方法中以四環黴素浸泡法表現最好,噴槍法次之,染色法則不適合,而四環黴素浸泡法和噴槍法,以及雙重標識法的四環黴素投餵法和噴槍法均是適合金目鱸魚苗的大量標識法,此外,雙重標識法的四環黴素投餵法和噴槍法也擁有較低操作成本和較多個體可以被標誌。
In recent years, because of the coastal fishery resource decline, the hatchery-reared fry of both black porgy (Acanthopagrus schlegeli) and giant sea perch (Lates japonicus) were commonly mass released to the surrounding waters in Taiwan. Even though the releasing programs were in process for many years in Taiwan, the releasing effects were not often assessed. Therefore, it is necessary to examine several suitable mass marking methods with a high marks retention rate, an operations time saving, an avoidance of stress due to handling, an inexpensive and labor saving process, for the fry in order to assess the effects of releasing programs. In order to study the mark retention rates and survival rates of three marking treatments, i.e., immersing fish bodily into a water solution containing comestible pigment with a dye for the body surface (MD), immersing the fish into a water solution containing tetracycline to mark calcified hard tissue (MI), spraying harmless pigment with fluorescent material to mark the skin (MS) and the control, two species of black porgy and giant sea perch were examined respectively, from June to October, 2004. In addition, a double marking method, i.e., spraying harmless pigment with fluorescence to mark skin (MS) after feeding fish mash containing tetracycline to mark calcified hard tissue (MF) for two weeks, was examined if it could increase marks retention rate for giant sea perch in November, 2004. Based on the comparisons of mark retention rates and survival rates, MI is, MS may be, and MD is not a suitable method for black porgy. Both MI and MS are suitable methods while MD is not a suitable method for giant sea perch. The double marking method of combining MS and MF is good and suitable for giant sea perch. Both MS and MF also have lower costs and more individuals can be marked.