為究明不同規格刺網在台灣沿海漁場的漁獲效果，本研究利用9.4、9.8、10.7、11.3及11.8 cm等五種不同網目之單層刺網，及內網10.3 cm，外網30.4 cm之三層刺網，在嘉義布袋沿海以黑鯛為主要對象，進行刺網選擇性實驗。結果顯示，小網目的單層刺網與三層刺網之漁獲魚種及尾數相近；其中，9.4 cm網目較易漁獲體型小及未成熟的個體；10.7 cm者之每單位努力量所漁獲黑鯛的收益 (IPUE) 較其他網目者為高。三層刺網所捕獲的每尾魚平均重量低於其他單層刺網，但因其漁獲總重較高，故整體漁獲經濟價值最佳。各不同規格刺網之經濟性漁獲物與全部漁獲物之比例值 (C/T)，無論以尾數或重量計，其值均高於0.82，表示沿海刺網漁業之漁獲物皆受到高度利用。
分析黑鯛之尾叉長別對不同網目之選擇性，結果顯示，在盛漁期，若欲漁獲之黑鯛尾叉長 (FL) 與選用網目 (M) 間的關係為：FL∕M＝2.63時，單層刺網對黑鯛之漁獲效果及整體漁獲效益較三層刺網佳；然而若考慮全部捕獲魚種，三層刺網之漁獲效果則較單層刺網佳，獲利亦較好。所以在黑鯛盛漁期間，以網目為10.7 cm 的單層刺網作業，可減少對漁場環境及資源的破壞，同時亦能兼顧漁獲收益。
|標題title(英)：||Selectivity of Different Size Gill Nets and Trammel Nets for Black Porgy, Acanthopagrus schlegelii, in the Coastal Waters of Chiayi|
|作者 auther(英)：||Chi-Chang Lai, Ching-Min Yang, Chang-Yang Huang, Kuan-Yung Hsieh and Long-Jing Wu|
|摘要abstract(英)：||To understand the catch effect of different scales or nets in Taiwan’s coastal fishing grounds, five different gill net mesh sizes (9.4, 9.8, 10.7, 11.3, and 11.8 cm) and trammel nets (inner panel mesh size: 10.3 cm) were used on black porgy (Acanthopagrus schlegelii) as the target species in the coastal water of Budai, Chiayi in February to March 2004. Results indicated that the caught effects on the species and its mantissa were similar between the small mesh gill net and the trammel net. Small size or immature fish were caught with greater ease using the 9.4 cm mesh size gill net and the trammel net, while the black porgy of higher IPUE was caught with greater ease using the 10.7 cm mesh size net. The average weight of the fish captured with the trammel net was lower than those caught with the other gill nets; however, due to the higher total weight, the trammel net had the highest overall economic value. The proportion of economy catches and total catch value (C/T) of all survey nets were higher than 0.82, indicating that the captures of the different mesh sizes of gill nets and trammel nets are subject to intensive utilization in the coastal zone.
In terms of the relationship between the fork length of black porgy and mesh selectivity, if the mesh was selected properly (i.e., the relationship of Fork Length (FL) and Mesh size (M) is FL / M = 2.63), the catch effect and incomes of the gill net were greater than those of the trammel net during the fishing season for the black porgy. If only the total catch was considered, however, the catch effect and incomes of the trammel net were greater than those of the gill nets. Therefore, in order to reduce the impact on the environment and increase the conservation of fishery resources, while maintaining catches income, we recommend that the most appropriate mesh size gill net (10.7 cm) should be chosen for the black porgy fishing season.