本研究於2007年2月起至2008年4月止，針對宜蘭縣延繩釣漁民發放漁撈日誌，共計回收9艘樣本船，總計投繩352次。根據漁撈日誌分析結果顯示，海豚和大型鮫類破壞率(Damage rate)分別為33.24%和22.44%，尾數咬食率(Predation rate in number)分別為10.20%與2.10%，重量咬食率(Predation rate in weight)為9.52%和2.22%，咬食指標(Depredation index)則分別為4.62及0.88。海豚咬食的漁獲主要以鬼頭刀、黃鰭鮪及黑鮪，主要損失為黑鮪、鬼頭刀、黃鰭鮪；而大型鮫類主要咬食魚種則為鬼頭刀、油魚和旗魚，主要損失為鬼頭刀和油魚。而本研究依漁獲量推估南方澳延繩釣漁業漁獲被海豚及大型鮫類咬食總損失分別為台幣86,726,089元和 17,100,649元，各佔南方澳延繩釣漁業收益之9.08%和1.79%。而以作業漁船努力量推估南方澳延繩釣漁業被海豚咬食損失為 89,713,628，95%之信賴區間為64,740,458~114,686,798元。此金額佔2007年度南方澳地區延繩釣漁船總收益的 7.29%~12.92%，平均為10.10%。被大型鮫類所咬食之總損失為7,798,142元，佔總收益的0.87%，95%的信賴區間分別 6,185,564~9,410,720元和0.70%~1.05%，平均為0.87%。
Total of 352 fishing operations of Nanfangao fishing vessels during February 2007 to April 2007 were recorded by the questionnaires. The catch damage rates by dolphins and sharks were 33.24% and 22.44%, respectively. The depredation rates in number and weight by dolphins were 10.20% and 9.52%, while those rates by sharks were 2.10% and 2.22%, respectively. Moreover, the depredation index by dolphins and sharks were 4.60 and 0.88. It also indicated that the dolphins preferred to bite dolphin fish, yellowfin tuna and bluefin tuna, however sharks preferred to bite dolphin fish, oil fish and billfsih. Based on the annual yields of Nanfangao longline fishery. The total depredation loss by dolphin and shark of Nanfangao longline fishery were respective NT 86,726,089 and NT 17,100,649 dollars, which occupied 9.08% and 1.79% of total income of Nanfangao longline fishery, respectively.