THE LINIVERSITY OF MANITOBA INDICATORS (PARASITES AND STABLE ISOTOPES) OF TROPI{IC STATUS OF YELLOW PERCH (PERCA FLAVESCEI\IS MITCI_IILL) IN NUTRIE\IT POOR CANADIAN SI{IELD LAKES. BY MICIJAEL W. JOFINSON A THESIS SUBMITTED TO THE F'ACULTY OF GRADUATE STUDIES IN PARTIAL FULFILLMENT OF Ti]E REQUIREMENT FOR THE DEGREE OF MASTER OF SCIENCE DEPARTMENT OF ZOOLOGY WINNIPEG, MANITOBA O AUGUST 2OO1 NationarLibrarv nationale l*l 3f3"",Håå" Acquisitions and Acquisitions et Bibiiographic Services services bibliographiques 395 Wellingrton Streêt 395, rue Wellington OttawaON K|AoN4 OttawaON KtA0N4 Canada Canada Yout il€ Voùø rélérencâ Our 6le |toûa rélércnce The author has granted a non' L'auteru a accordé une licence non exclusive licence allowing the exclusive permettant à la Natíonal Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or sell reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microñche/fiIm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. 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TABLE OF CONTENTS ABSTRACT LIST OF TABLES IX LIST OF FIGURES INDIVIDUAL LAKE CI_IARACTERI STIC S L240........ .........7 L377 ........ ....... 10 Triangle Lake......... .......... 13 Triangle Lake bathymetry analysis ....14 CI{APTER I : I{ISTORICAL INTRODUCTION t7 FISH PARASITES............... ................. 18 Monogenealls ............ .. ... 19 Digeneans ....... 19 Cestodes .........21 Nematodes ......21 Acanthocephalans,..... .......22 Crustaceans................ .......22 PARASITE COMMLTNITIES ...........,...23 YELLOW PERCH GROWTI_I AND THE INFLUENCE OF PARASITES ................26 STABLE ISOTOPES ..........32 Fractionation Process .......34 Stable Isotopes in Animals ................. 35 CIIAPTER 2: PARASITOLOGICAL AND DIETARY SURVEY OF SOME EXPERIMENTAL LAKES AREA FISHES WITH AN EMPI]ASIS ON YELLOW PERCH PARASITE ASSEMBLAGES....... ...............47 INTRODUCTTON ...............48 METHODS AND MATERIALS ............ ................49 Sarnple colìection and examination.,........ ............49 RESULTS .......... s3 Fish morphometrics.... ...... 53 Fish stomach contents ......57 Seasonal dietary trends........ ...............65 Age-related dietary trends ..................74 Parasite fauna ...................83 Seasonal trends in yellow perch infèction statistics ............. 120 ll Age and sex related trends ir-r yellow perch infèction statistics.... .......... 120 DISCUSSION............ ........ 133 Parasite fàuna ................. 133 Fislr diet and parasite infection trends........ ........137 CI{APTER 3:YELLOW PERCH PARASITE COMMUNITY PATTERNS AND PREDICTABILITY . .........142 INTRODUCTION 143 MATERiALS AND METHODS 141 Tenninology ...,........,.. 141 Stati stical analyses.... 148 RESULTS t49 Parasite fàuna dominance, richness and diversity.............. t49 Yellow perch age and length vs. infectiol1............... 159 Parasite cornmunity predictability.............. 165 DISCUSSION............ t72 Parasite communities.............. 180 Host characteristics 180 Predictability ............. 182 Nestedness 18s Diet.......... ..... 186 Other biotic and abiotic factors ... ... 188 CI_IAPTER 4: PARASITE EFFECTS ON TI{E SURVIVAL. GROWTI_I AND REPRODUCTIVE POTENTIAL OF YELLOW PERCI_I IN CANADIAN SHIELD LAI(ES. 190 INTRODUCTION ............. 191 METHODS AND MATERIALS ............ .............. 191 Parasite identification and distribution ............... 191 Partitioning fish ancl parasite data for analyses ....................192 Statistical analyses.... ...... i95 RESULTS ........ 195 Glugeu sp. infections.............. .......... 195 Apophallus brettis infèctions ............203 Raphidosccrris ctctts infectior-rs.. ........212 DISCUSSION..,......... ........219 Relationship among visceral fat and weight of gonads and soura... .......223 Mortality.. .....226 CI_IAPTER 5: PARASITES AND STABLE ISOTOPES AS PREDICTORS OF. YELLOW PERCI_I TROPHIC STATUS... ...-...........230 INTRODUCTION ...........,.231 METHODS AND MATERIALS ............ ...,.....,.,..233 Stable Isotope Sample Selection ......233 Stable isotope sample preparation and analysis ................ ...237 Statistical analyses.... ......237 lil RESULTS ........238 DISCUSSION............ ........264 CI-IAPTER 6: SUMM4RY............ .........272 PRIMARY POINTS.... ,.,273 SECONDARY POINTS ............... ...282 LITERATURE CITED .........285 APPENDICES ............ ..........321 ABSTRACT Tlre fish parasite communities of four Canadian Shield lakes (L239,L240,L377 and Triangle Lake) in the Experimental Lakes Area (ELA), Ontario were slrrveyed over tlrree seasons in 1997 and 1998 and one seasorì in 1999. Thirteen of fifteen lish species sanrpled from the study lakes harboured parasites; northern pike (ðsox luciu,t).lake cisco (Coregonus urtedii), pearl dace (Mcu"gcrriscus margurila), blacknose shiner (Nolropis heterolepis), spottail shiner (Nolropis hudsonius), fathead minnow (Pintephales prornelas),longnose dace (Rhinichtlry,r calaructae), white sucker (CatosIontus cot'tlnler,tonl), burbot (Lota lolcr), brook stickleback (Culeu inconslans), sliury sculpin (Cotttt,s cogncrlus),lowa darter (Etheostomct exile) and yellow perch (Perccr flut)escens). A total of ll2,I88 parasites were detected, with 87o/o (n: 1926) of the necropsiecl fìsh having at least one parasite. Forty-one species of parasites representing 32 genera and26 families were found; 35 species used fish as definitive hosts and six species usecl birds as the definitive hosts. The most omnivorous fìsh species (perch, white sucl<er and pearl dace) had the most diverse parasite infracommunities wliile the most specialized consumers had the least diverse parasite infracommunities (the piscivores, pike and burbot and the zooplanktivorous cisco) or lacked parasites entirely (the algavorous nortlrern reclbelly dace, Phoxintß eo,s, and finescale dace, P. neoS;¡neus). The parasite communities of the four ELA lakes were less speciose than those reportecl fì'om larger lacustrine systems in Ontario and Manitoba. The parasite community composition of yellow perch was typical of perch in other systems, however, there were new host and locality records for several parasite species infecting other fish species. For example, the pearl clace was inf-ected with five parasites not pleviously leported from this host in North Alnelica and two not previously reportecl fì'om this host in Canada. There rvere clistinct seasonal and age-related trends in the parasite commur-rities of yellow perch populations that correlated with seasonal and ontogenetic clietary shifts, respectively. Unclerstanding parasite community structure can improve understandirrg of host population ecology and clarify lrany aspects of ecosystem biotic ancl al¡iotic interactions. Detailed analysis as perforrned in this study is a useful tool f.or clescribing the factols affecting parasite community cornposition. A restricted invertebrate and fish fauna in these nutrient poor lakes can be important in controlling the parasite fauna infècting yellow perch, which could be more predictable than that observed in large, productive lakes. Allogenic parasites are most comlllon in Triangle Lake and enterics inL239. Parasite species richness is highest inL239 and diversity is highesf inL240. Glugect sp. is the most dorninant and abundant parasite species in all but Triangle Lake. Triangle Lalce and L377 perch have the fastest growth rates and reach the greatest total length ar-rcl age of all sampled perch. Yellow perch length and age are both highly correlated with parasite richness, intensity and abundance. Female perch usually had significantly greater species richness than males but intensity and abundance were signifìcantly higher tlran males in only two lakes each. L239 and Triangle Lake had parasite assemblages that were signifìcantly non-ranclom largely clue to subpopulations of parasite species transmitted through macrobenthos. Perch parasite colnmunities in all four lal<es showed significantly lnore nestedness than expected by chance. Parasite-induced pathology of yellow