DFC PRffiEEDnics - ALpFiABE-ncAL usrlt$c oFABSTRAgTS

Year: 1995 (xxvii)

Abstract

The use of isolated ponds to raise bonytail chub and razorba& su&ers is well known through theefforts of the Ilke Mohave Native Fish Group at l^ake lvlohave, AZ-NV. This talk presents informadt onsimilar efforts on t}re Bill Williams River, Ciboia, Havasu, and Imperial National wlam“ Refuges, and inthe La Paz Cor:ntyqolf cor:rse Ponds. It briefly discusses the successes and failures of these “t”“” “l-,d reportson the releases made into lower basin waters during 1995. Plans for 1996 are also brielly d.iscussed. R.ESUMEN El uso de estanques aislados para la liberaci6n dei charaiito elegante y el matalote jorobado, son bienconocidos a travds de los esfuerzos del l^ake Mohave Native Fish Gioup en el lake Mohave AZ-NV. Estacomr:nicaci6n presenta informaci6n sobre esfuerzos similares en el Bill Witti”rtr River, Cibola, Havasu, andimperial National Wildlife Refi.rges y los estanques del curso de golf del-apaz County. Se discuten ?:t:11t: t“S.J fracas,ol j; estds 5.reas y los reportes sobre las liberaciones realizadas en las aguas de las cuencas baias duranie 1995. Los planes para tllO son tambidn brevemente d.iscutidos. MoNoa, D.‘; WacNER, P. (F/nnidr.r€Fi.hdis) 9:y:lgp*g-an understanding of the pyramid I^ake ecosystem KEYWORDST q/.”id l,ake; Iahontan cutt]’rroat trout; cui-ui; nitrogen The $namid lake Fisheries Restoration Project (PLF) was established in i975 to insure the sr:rvivalof fish populations in B/ramid lake. The populations of greatest concern are the si-.ur Qtasmistes cujus andthe Lahontan cutthroat trout Oncorhlmchus clarkt henshaxlt (LCT). The cui-ui is currently tisted xendangered, while the LCT is listed as threatened, so that a sport fishery can be sustained- - Limnological and ecologiul research conducted by W.F. Siegler and Assoaates in l97g, D.L. Galatfrorn 1976 to the early 1980’s, and the limnological Research Gro,ri at the Universiry of California - Davisfrom 1989 to 1995 laid the for:ndation opon -hi.h PLF continues to build. It is now well established that ryttaid is a nitrogenlimited lake, and that the Truckee River and internal blooms of the nitrogen-fixingalgae Nodul’aria syymigena,are the maior sources of nitrogen input. Phosphorus is limiting only duringintense,l/adulariabloorns. Large amounts of nitrogen .rt .i.o be lost fro.n ih. rystem: durilg years whenlake stratification does not break down and hypolimnetic water does not get mixed, anodc cond.itions arecreated’ and denitrifying bacteria convert nitrate and nitrite to nitrogen gas which then diffuses to theatmosphere. 6B