) ▁is ▁native ▁to ▁South ▁Africa ▁but ▁does ▁not ▁occur ▁naturally ▁in ▁the ▁Twe e ▁River ▁re df in ' s ▁range ; ▁it ▁has ▁been ▁introduced ▁to ▁the ▁Su ur v lei ▁River , ▁however . ▁The ▁kur per ▁compet es ▁with ▁the ▁re df in ▁for ▁food ▁and ▁probably ▁also ▁e ats ▁young ▁B . ▁er ub esc ens . ▁It ▁is ▁the ▁probable ▁cause ▁for ▁the ▁re df in ' s ▁disapp earance ▁from ▁the ▁lower ▁Su ur v lei ▁River . ▁Compet ition ▁with ▁the ▁Cl an will iam ▁yellow fish ▁( L abe obar bus ▁cap ensis ) ▁– ▁another ▁South ▁African ▁native ▁that ▁was ▁introduced ▁to ▁the ▁re df in ' s ▁range ▁– ▁has ▁reduced ▁B . ▁er ub esc ens ▁stock s ▁in ▁the ▁Twe e ▁River . ▁Iron ically , ▁both ▁introdu ctions ▁were ▁well - mean ing ▁but ▁mis gu ided ▁attempts ▁to ▁deal ▁with ▁problems ▁caused ▁by ▁animals ▁introduced ▁from ▁foreign ▁countries , ▁that ▁failed ▁to ▁take ▁into ▁account ▁the ▁extremely ▁high ▁level ▁of ▁local ▁en dem ism ▁in ▁Western ▁Cape ▁Province ▁– ▁and ▁in ▁the ▁case ▁of ▁the ▁Cl an will iam ▁yellow fish ▁were ▁even ▁supported ▁by ▁the ▁Cape ▁Department ▁of ▁Nature ▁Conserv ation . ▁The ▁ex otic ▁fish es ▁that ▁are ▁harm ful ▁to ▁the ▁Twe e ▁River ▁re df in ▁are ▁the ▁bl u eg ill ▁( L ep om is ▁macro ch irus ) ▁and ▁the ▁rain bow ▁tr out ▁( On cor h yn chus ▁my