ales ▁disappeared ▁from ▁the ▁area ▁after ▁a ▁strong ▁El ▁Ni ño ▁year ▁in ▁ 1 9 8 2 ▁and ▁ 1 9 8 3 , ▁and ▁have ▁since ▁been ▁encountered ▁inf re qu ently , ▁primarily ▁during ▁warm - water ▁years ▁such ▁as ▁ 1 9 9 1 , ▁ 1 9 9 3 , ▁ 1 9 9 7 , ▁ 2 0 1 4 , ▁and ▁ 2 0 1 5 . ▁It ▁is ▁not ▁known ▁whether ▁the ▁animals ▁sight ed ▁more ▁recently ▁were ▁part ▁of ▁the ▁same ▁population ▁that ▁was ▁documented ▁off ▁Southern ▁California ▁before ▁the ▁mid - 1 9 8 0 s , ▁or ▁a ▁different ▁wide - r anging ▁pel ag ic ▁population , ▁therefore ▁the ▁status ▁of ▁this ▁stock ▁remains ▁unknown . ▁ ▁Pil ot ▁wh ales ▁are ▁econom ically ▁important ▁in ▁the ▁wh ale - watch ing ▁industry ▁of ▁some ▁areas ▁of ▁the ▁world , ▁such ▁as ▁Made ira , ▁Hawai i , ▁and ▁the ▁Can ary ▁Islands , ▁which ▁host ▁resident ▁populations ▁of ▁these ▁wh ales . ▁The ▁effects ▁of ▁tour ism ▁activities ▁on ▁pilot ▁wh ales ▁have ▁not ▁been ▁well ▁studied , ▁but ▁some ▁evidence ▁suggests ▁that ▁the ▁impact ▁of ▁under water ▁noise ▁from ▁wh ale - watch ing ▁boats ▁can ▁have ▁the ▁potential ▁to ▁significantly ▁dis rupt ▁communication ▁at ▁close ▁range . ▁Many ▁countries ▁offer ▁safe ▁wh ale - watch ing ▁gu idel ines ▁designed ▁to ▁minim ize ▁the ▁impact ▁of ▁their ▁activities ▁on ▁the ▁animals ▁being ▁watched ▁( see ▁supp lement ary