8234

• UCREFRP Catalog Number: 8234
• Author: Marsh, P. C. and M. E. Douglas
• Title: Predation by Introduced Fishes on Endangered Humpback Chub and Other Native Species in the Little Colorado River, Arizona
• USFW Year: 1997
• USFW - Doc Type: Transactions of the American Fisheries Society
• Copyright Material: YES

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HF1.FptAN, C. S. 1981. Tx iligbt activities and lemprrral structure in a freshwater
fish community. Can. J. Fish. Aquas. Sci. 38: 1405-1420.
Kit.4Ft. N1. E. 1972. Effects of controlled flow reduction on a trout stream.
J. Fish. Res. Board Can 29: 1405-1411,
ORTH. D. J. 1980. Evaluation of a methodology for recommending instreant
fio«s for fishes. Doctoral dissertation. Oklahoma State University.
Stillwater. OK.
ORM, D. J.. AND O. E. MAU011.4N 1982. fva!uation of the lucremenlai
Methodology for recomntcndine instream f1w.c for fishes. Trans. Am.
Fish. Soc. 111: 413-445.
1983. MicrohaNtad preferences of bentt•:ic fauna in a a,r-odlaad
stream. Hydrobiologia 106. 15'-164.
Comparison of the Phosphorus-Chlorophyll Relationships.
in Mixed and Stratified Lakes
E. T. Riley' and E. E. Prepas
Department of Zoology, University of -1lberta, Edmonton, Alta. T6C' 2E9
Riley, E. T., and E. E. Prepas. 1985. Comparison of the phosphorus-chlorophyll relationships in mixed and
stratified lakes. Can. 1. Fish. Aquat. Sci. 42: St1-835.
Data from the literature were used to calculate separate regressions of summer chlorophyll a concentra-
tion ([Chi a]) on spring total phosphorus concentration ([TPD for lakes that remain thermally stratified
during the summer and lakes that mix intermittently during the summer. Significant differences were
found in the spring [TPI - summer [Chi a[ relationships for the two lake types (P < 0.05). The mean ratios of
summer [TPJ to spring [TPJ were also significantly different in stratified and mixed lakes (P < 0.001); this
difference is the explanation offered for why the spring ITPI - summer [Chi a) relationships were different
in stratified and'mixed lakes.
Des donnees tirees d'ouvrages pubfies ont 6te utilisdes pour calculer differences regressions entre la
concentration estivale de chlorophylle a ([Gill a]) et )a concentration totale printaniere de phosphore total
([PTI) dins des lass qui restent thermiquement stratifies pendant I'M6 et d'autres la( s qui se mclangvill de
faSon intermittenle en 616. Des differences significative,, not 6t6 d6couvertes Bans les relations IN I au
printemps el [ChI a] en 616 clans les deux genres cle lac (P < 0,05). Les rapports moyens eAre la (1111 en 06
et la [PT] au printemps 6taient aussi significativement diffdrents dans les lass stratifies et les [acs rnOang6s
(P < 0,001) ; cette difference ser"t A expliquer la difference dans les relations IPTJ au printemps - lChl a] en
6te, clans les lass stratifies et melanges.
Received May 16, 1984
Accepted December 37, 1984
(J7F00)
Re4u le 10 mai 1984
AccePle le 31 decewhre 19,14
Total phosphorus JP) is a good predictor of the standing
crop of phytoplankton in lakes (Sakamoto 1966; Dillon
and Rigler 1974; Nicholls and Dillon 1978; Oglesby and
Schaffner 1978; Smith 1982; Prepas and Trew 1983).
Generally, spring ITPI.is the parameter used to predict the
summer chlorophyll if concentration QC'hI al). However; a
substantial cnnr is associated wifh predictions from f iesc
Illodels. I'o trducC this elf-or, atrthols nave imed variables other
than spring II'1'] as a predictor and IChl al as an indicator of
phytoplankton standing crop. Nicholls and Dillon (1978)
showed less error associated with predictions of algal biomass
than with summer IChl a]. Smith (1982) incorporated total
nitrogen concentration QTNI) along %vith [TPJ as a predictor of
summer [ChI a]. Prepas and Trew (1983). found that summer
'Present address: Biology Department. University of Pennsylvania.
Philadelphia. PA. 19104, USA.
JTPJ was a better predictor of summer [Chi a1 than spring I I P1.
However, spring 111`1 and summer [ChI of are ;!ill the most
useful variables in these nwdels, since spring ITI'I can he
predicted from loading models (Vollemceider and Kerekes
1980) and [ChI a] and spring I*TPI are much easier ba nuasure
than phytoplankton hirmrass and summer ['I'l'l
One source of varialion in the spring 11111 minmu•r IC'hl al
relationship that has been proposed, but ii-it thoiolly111y IC?tcll
for, is the influence of mixing patterns. It has been ?uggc,Acd
that mixed lakes (i.e. lakes that mix intermittently cltiring the
summer) produce nwre summer Chi a per unit of spring TP
than stratified lakes (i.e. lakes that remain thermally stratified
during the summer). Oglesby and Schaffner (19751 assumed
that the winter [TP] - sununer [Cpl a] relatimmchips are different
in the two lake types and calculated separate linear reegressiom
of'summer [ChI al on vvinter [TPJ for stratified and mixed lakes.
Although there %%as generally more Chi if per unit 11) in the
Can. J. Fish Aqu,ar. Sci., Vol. 42. 19A5 g' I