WHITE­BAIT UN­DER THREAT

Boating NZ - - Feature -

There’s an ele­phant in the room: white-bait­ing.

White­bait is the fry (ju­ve­niles) of five na­tive fresh­wa­ter fish species. Of the na­tive fresh­wa­ter fish con­sid­ered en­dan­gered – īnanga, short­jaw kōkopu, gi­ant kōkopu, kōaro, kanakana/pi­ha­rau (lam­prey), and tuna (longfin eel) – the first four in the list con­sti­tute ‘white­bait’, along with banded kokupu, which is not threat­ened.

White­bait catches fluc­tu­ate wildly from year to year and the mix of species that make up the catch also varies, be­tween sea­sons and from place to place. The con­sen­sus among fish­ers is that white­bait catches are on aver­age worse to­day than 40 years ago. Anec­do­tally, the species com­po­si­tion of the catch is chang­ing as well, but I could find no re­search to back this up.

The white­bait fish­ing sea­son varies by re­gion. Un­like trout and sal­mon (or recre­ation­ally caught sea fish), or­di­nary cit­i­zens are al­lowed to sell white­bait on the open mar­ket, which tempts some fish­ers to op­er­ate com­mer­cial-scale op­er­a­tions. Every year many tonnes of white­bait are har­vested.

Many white-bait­ing reg­u­la­tions are ar­chaic, dat­ing back to 1894, and the rules are of­ten poorly po­liced, leav­ing the fish­ery vul­ner­a­ble to abuse.

Many peo­ple con­sider the con­tin­ued har­vest of en­dan­gered fish is only mak­ing their sur­vival more un­cer­tain. Per­haps a first step to slow the de­cline of na­tive fish might be to bet­ter reg­u­late white­bait fish­ing. Some would ar­gue it’s time to close fish­ing al­to­gether, at least un­til New Zealand re­ha­bil­i­tates its fresh­wa­ter en­vi­ron­ments. If we re­store spawn­ing and adult habi­tat, the na­tive species that make up white­bait might just beat ex­tinc­tion. SUP­PORT­ING FIND­INGS FROM THE STUDY • Ni­trate-ni­tro­gen con­cen­tra­tion was 18 times higher in the ur­ban land­cover class, and 10 times higher in the pas­toral class com­pared with the na­tive [for­est] class for the pe­riod 2009-13. • Ni­tro­gen leach­ing from agri­cul­tural soils was es­ti­mated to have in­creased 29 per­cent from 1990 to 2012. • Dis­solved re­ac­tive phos­pho­rus con­cen­tra­tion was three times higher in the ur­ban class and 2.5 times higher in the pas­toral class com­pared with the na­tive class (2009-13). • E.coli con­cen­tra­tion was 22 times higher in the ur­ban land-cover class and 9.5 times higher in the pas­toral class com­pared with the na­tive class (2009-13). • Of the 39 na­tive fresh­wa­ter fish species re­ported on, 72 per­cent were ei­ther threat­ened with (12 species), or at risk of (16 species), ex­tinc­tion in 2013. • De­clines in con­ser­va­tion sta­tus were ob­served for four species be­tween as­sess­ment pe­ri­ods (2009 and 2013) – Cen­tral Otago round­head galax­ias, Can­ter­bury galax­ias, black mud­fish, and kanakana/ pi­ha­rau (lam­prey).

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