Nematode Parasites of Yellow Perch, Perca flavescens, from the Laurentian Great Lakes

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1 J. elminthol. oc. Wash. 66(2), 999 pp Nematode Parasites of Yellow Perch, Perca flavescens, from the Laurentian Great Lakes PATRICK. UZZALL Department of Zoology, Natural cience Building, ichigan tate University, ast Lansing, ichigan U..A. ( ABTRACT: Yellow perch, Perca flavescens (itchill), from 4 localities in the Laurentian (North American) Great Lakes were examined for nematodes: from eastern Lake ichigan in 99; from southern Lake ichigan in 99; from The Black ole, aginaw Bay, Lake uron in 99; and from Oak Point, aginaw Bay, Lake uron in 996. Dichelyne cotylophora (Ward and agath) infected perch from each location and had the highest prevalence, mean intensity, and mean abundance at Oak Point. ustrongylides tubifex (Nitzsch) Jagerskiold was a common parasite of perch from aginaw Bay, but it infrequently infected Lake ichigan perch. Philometra cylindracea (Ward and agath) Van Cleave and ueller was found in perch only from aginaw Bay. Contracaecum sp. infrequently infected perch from Lake ichigan and The Black ole. A comparative summary of the literature on nematodes infecting yellow perch from the Great Lakes is presented, listing 27 studies published since 97. Four nematode genera utilize perch as intermediate hosts, and 5 genera utilize them as definitive hosts. Information on the life cycles and pathology caused by nematodes infecting yellow perch is presented. KY WORD: Yellow perch, Perca flavescens, Percidae, Pisces, parasites, nematodes, Laurentian Great Lakes, Lake ichigan, Lake uron, aginaw Bay. everal nematodes have been reported from yellow perch, Perca flavescens (itchill, 84) (Percidae), in the Laurentian (North American) Great Lakes. In recent years, federal and state fisheries personnel, aquaculturists, and anglers have asked me to identify nematodes infecting yellow perch from the Great Lakes and to answer questions about them. Declines in the catch rates of perch have been reported in southern Lake ichigan; aginaw Bay, Lake uron; and western Lake rie (Francis et al., 996). The present study reports on the occurrence of Dichelyne cotylophora (Ward and agath, 97); ustrongylides tubifex (Nitzsch, 89) Jagerskiold, 99; Philometra cylindracea (Ward and agath, 97) Van Cleave and ueller, 934; and Contracaecum sp. in yellow perch from Lake ichigan and aginaw Bay, Lake uron. A summary of the nematodes infecting yellow perch from the Great Lakes is presented, with accompanying information on their life cycles and pathology. The possible relationship between the decline of yellow perch populations in some areas of the Great Lakes and the occurrence of parasitic nematodes is also discussed. aterials and ethods A total of 364 yellow perch was collected by beach seine and trawl from southern Lake ichigan (ichigan City, Indiana) in 99; eastern Lake ichigan (Ludington, ichigan) in 99; aginaw Bay, Lake uron (The Black ole) in 99; and aginaw Bay, Lake uron (Oak Point) in 996. Ludington is approximately 247 km north of ichigan City. Fish were sampled from the open water in Lake ichigan and also along the shore at Ludington. aginaw Bay, a large shallow eutrophic bay divided into inner and outer areas, is the southwestern extension of Lake uron located in east central ichigan. The inner area is shallower and warmer than the outer area, and is enriched with domestic, agricultural, and industrial inputs from the aginaw River. The Black ole in the Inner aginaw Area and Oak Point in the Outer aginaw Area are approximately 5 km apart. Perch were put on ice in the field, frozen at the laboratory, and measured and sexed at necropsy when the abdominal cavity, viscera, muscle, gastrointestinal tract, and head were examined. Dichelyne cotylophora, ustrongylides tubifex, and Contracaecum sp. were preserved in 7% alcohol and later cleared in glycerin for identification. Philometra cylindracea were broken during necropsy and pieces were placed in glycerin on a glass slide, allowed to clear, and examined with a light microscope; specimens were not kept. Prevalence is the percentage of fish infected in each sample, mean intensity is the mean number of nematodes of a species per infected fish, and mean abundance is the mean number of worms per examined fish. Voucher specimens have been deposited in the United tates National Parasite Collection (UNPC), Beltsville, aryland 275: Dichelyne cotylophora (UNPC 8856) and ustrongylides tubifex (UNPC 8857). Results Yellow perch from 2 locations in Lake ichigan and 2 locations in aginaw Bay, Lake uron, were examined for nematodes (Table ). 5 Copyright 2, The elminthological ociety of Washington

2 6 JOURNAL OF T LNTOLOGICAL OCITY OF WAINGTON, 66(2), JULY 999 Table. Number, collection time, and mean total length (mm) of Perca flavescens examined from Lake ichigan and aginaw Bay, Lake uron. Location onth(s), year ean total length ± D (range, 95% confidence interval) ichigan City, Indiana, southern Lake ichigan ()* August 99 Ludington, ichigan, eastern Lake ichigan (64)* ay-eptember 99 The Black ole, inner aginaw Bay, Lake uron, ichigan eptember 99 ()* Oak Point, outer aginaw Bay, Lake uron, ichigan ()* August ± 67(5-28, 4-68) 36 ± 23(5-77, 3-42) 72 ± 36(-278, 64-78) 22 ± 23(7-287,97-26) * (Number of yellow perch examined.) There was a significant difference in the lengths of perch between locations (analysis of variance, F = 35.9, P <.) with those from Oak Point being larger. Forty-eight percent (48) of yellow perch from ichigan City in 99, 26% (7) from Ludington in 99, 96% (96) from The Black ole in 99, and 98% (98) from Oak Point in 996 were infected with or more nematodes. Gravid Dichelyne cotylophora infected the intestines of yellow perch from each location (Table 2). It was significantly more prevalent in perch from ichigan City than from Ludington, ichigan (chi-square, x2 = 26.6, P <.5); intensities were not significantly different, but abundances were (ann-whitney test, U = 9,87, P <.). In aginaw Bay, prevalence (chi-square, x2 = 28.6, P <.5) and abundance (ann-whitney test, U = 6,64, P <.) of D. cotylophora were significantly higher in perch from Oak Point than from The Black ole. Contracaecum sp. infrequently occurred encysted on the surface of the heart, in the liver, and associated with the mesentery of perch from Lake ichigan and The Black ole. ustrongylides tubifex was most common in perch from aginaw Bay. The intensity (ann- Whitney test, U = 9,773, P <.) and abundance (ann-whitney test, U = 2,798, P <.) of. tubifex were significantly higher in perch from The Black ole than from Oak Point. Larvae occurred in capsules associated with the mesentery on the surface of the ovaries, testes, liver, spleen, and gastrointestinal tract and free in the body cavity, viscera, and muscle. Of the 33. tubifex found in perch from Oak Point in 996, 92% of the worms or capsules with worms were seen with the unaided eye, whereas 8% were detected only with a dissecting microscope. mall and large. tubifex were found in perch from both aginaw Bay locations. Philometra cylindracea, some of which were larvigerous, occurred free in the body cavity of perch only from aginaw Bay, and was most common at Oak Point. Remains of crenulated and hardened masses of nematodes, probably dead P. cylindracea from past infections, were found in the body cavities and viscera of yellow perch from The Black ole and Oak Point. All perch from aginaw Bay in 99 and 69% of them in 996 that were infected with P. cylindracea were concurrently infected with. tubifex. Ninety-six percent of Oak Point perch harbored at least. tubifex or P. cylindracea or remains of dead P. cylindracea. There were no significant differences in the prevalence (chi-square analysis, P >.5) and intensity or abundance (ann-whitney test, P >.5) of D. cotylophora,. tubifex, P. cylindracea, and Contracaecum sp. between female and male perch at any location. There were no significant correlations between the intensities of each nematode species and host length. Discussion At least 27 studies mentioning the nematode parasites of yellow perch from the Great Lakes have been published since 97. The number of studies (in parentheses) performed in each Great Lake and associated connecting waters are: Lake ichigan (5), Lake uperior (), t. arys River (), Lake uron (7), Lake t. Clair (), Lake rie (2), and Lake Ontario (3) (Table 3). any of these investigations did not report the number, length, and age of perch. Rosinski et al. (997) reported that the nematode fauna of yellow perch in aginaw Bay, Lake uron, and Lake uron proper are similar. Copyright 2, The elminthological ociety of Washington

3 UZZALL NATOD OF YLLOW PRC 7 3 o C 55 ^U 4 A U c *aa ) cd e 'o I 4> U T3 C e a 3- ^n ) A 3 3 g 3 * ^ 4J OB I. c «g^" fe, rti C3 u C It cs cfl " CL, a e as.c u cc 2 fi N, s o c ^. O 3" fe I 3 3" ff - J 2 x-^ : : U _J -^ ^,, X a _ D- ^ X a. < 2 ^_^ X d Cu * ^ 2 ^ ><. u * oo *' (^ d *o ^ NO (N C ^t r*".. ^ ^ (N (N d, + O O O in ^t _; -- rt r<- -* -- * ^ oo r- NO (N n V tr> d d r- d 3- >n o O O vo d d 6 d <N (N d r-^ + o c ON Tf Tj- >O O ON NO NO d ri + in oo r- d d ^ C r- o (N (N * OO ON CN OO r d m co in c* O C i d IN d ON* + O - **' - m r- rn > d «-5 "^ U a ~ g "f' If 5 - '^ (J t 3 a, ' a O ^«3 C C '5b «II n r u "o X 5 u x >> B 'oo C X 3 P B a J c _ o ) 3 j - j u c Cd ' -a g B is x - x ^n c D.*«-g ^ i e r-j J O TD y ] tu II "o J u s s.li i! v- ^^.{.}. A total of 5 nematode taxa has been reported from yellow perch in the Great Lakes (Table 3). Of these, Agamonema sp., Contracaecum sp.,. tubifex, ustrongylides sp., ysterothylacium brachyurum (Ward and agath, 97) Van Cleave and ueller, 934, Raphidascaris acus (Bloch, 779) Railliet and enry, 95, and Raphidascaris sp. are represented by larval or immature stages. Of the nematodes identified to species, 6 mature in the intestine of perch. Prevalence data from the literature indicate that D. cotylophora is the most common nematode infecting perch from Lake ichigan, R. acus is most common in Lake uperior perch, and D. cotylophora and. tubifex are most common in perch from Lakes uron and rie. The nematodes of perch from Lake Ontario have prevalences of 8% or less. The report of Bangham and unter (939) of Agamonema sp. from perch in Lake rie refers to an unidentified larval form, an immature nematode (J. Crites, pers. comm.), and will not be considered further. In the present study, Contracaecum sp. is reported for the first time from perch in Lakes ichigan and uron; all other nematodes found have been reported infecting perch from these lakes. Four nematode taxa were found in perch in the present study compared to the 5 nematode taxa reported in the literature. There are several possible reasons for this, including ) I only examined perch from 2 Lake ichigan locations and aginaw Bay, 2) more parasitological studies have been done on perch in Lakes rie and uron, and 3) it is difficult to determine if fish were collected from different habitats. It is pointless to discuss whether some nematodes of yellow perch have disappeared in the Great Lakes, because so few studies have been done in the past to which I can compare this study. Dichelyne cotylophora infects yellow perch from all the Great Lakes and is commonly found in the anterior intestine. Visible lesions were not observed at the sites of adult attachment. I have found worms up to 8 mm in length. Based on experimental evidence, Baker (984b) suggested that prey fish (cyprinid minnows) are intermediate hosts for D. cotylophora. This parasite is not host-specific to perch, since it has been reported from several fish species in Lake ichigan, t. arys River, Lake uron, Lake t. Clair, Lake rie, and Lake Ontario (Ward and agath, 97; Pearse, 924; Bangham, 933, 955; Bangham and unter, 939; uzzall, Copyright 2, The elminthological ociety of Washington

4 8 JOURNAL OF T LNTOLOGICAL OCITY OF WAINGTON, 66(2), JULY 999 Table 3. Reported nematodes of Perca flavescens from the Laurentian Great Lakes. pecies Lake* Prevalencet Locality Reference Agamonema sp.± 2(2/28) Bangham and unter, 939 Contracaecum sp.i 3 (3/) 8 (5/64) 4 (4/) IN ichigan City, this study Ludington, this study The Black ole, this study Camallanus oxycephalus 2(/45) 5 (5/93) 6 (45/735) 7 (27/48), Bangham and unter, 939 Bangham, 972 tromberg and Crites, 972 Cooper et al., 977 Dechtiar and Nepszy, 988 Dichelync cotylophora ustrongylid.es tubifex'j. ustrongylides sp. ± ysterothylacium brachyiintm^ Philometra cylindracea R LC O 8 9(/) 47 (47/) 9(2/64) 42(/24) 33 (24/73) 55(/2) 2(3/34) 4(4/) 68 (68/) 65 (45/69) (76/735) 5(6/2) 6 (25/48) 5 (7/5) 2 (4/374) 3 (3/) 35(293/83) 2(3/34) 8(93/24) 95 (95/) 74 (74/) 38 (9/5) 4 (34/735) 5 5 (24/48) 8(5/5) 8 (8/98) 33 (8/24) 4(6/48) 8(5/5) (2/2) 4(5/34) 24 (57/24) (/) 6(6/) WI WI, IL IN,, NY, PA IN Pearse, 924 Amin, 977 ichigan City, this study Ludington, this study Dechtiar and Lawrie, 988 uz/.all, 984 medley, 934 Bangham, 955 Dechtiar et al., 988 The Black ole, this study Oak Point, this study Ward and agath, 97 medley, 934 Bangham and unter, 939 Cooper et al., 977 Baker, 984a Baker, 984b Dechtiar and Nepszy, 988 Tedla and Fernando, 969 Tedla and Fernando, 97 Dechtiar and Christie, 988 Allison, 966 ichigan City, this study Allison, 966 Dechtiar et al., 988 The Black ole, this study Oak Point, this study easures, 988b Cooper et al., 977 Cooper et al., 978 Crites, 982 Dechtiar and Nepszy, 988 Dechtiar and Christie, 988 Bangham, 972 Dechtiar and Lawrie, 988 Dechtiar and Nepszy, 988 Dechtiar and Christie, 988 Bangham, 955 Dechtiar et al., 988 alz, 989 The Black ole, this study Oak Point, this study Copyright 2, The elminthological ociety of Washington

5 UZZALL NATOD OF YLLOW PRC 9 Table 3. Continued. pecies Lake* Prevalencet Locality Reference Raphidascaris acus$ Raphidascaris sp.t Rhabdochona canadensis oravec and Aral, 97 Rhabdochona ovtfikanenta Weller, 938 pinitectux carolini Roll, 928 pinitectus gracilis Ward and agath, 97 (/28) 8 (62/735) (4/48) 5(8/5) 63(5/24) 2(3/34) 8 (32/48) (/36) 8 (2/24) 9 (6/69) 8 (2/24) (2/5), Bangham and unter, 939 Cooper et al., 977 Crites, 982 Dechtiar and Nepszy, 988 Dechtiar and Christie, 988 Dechtiar and Lawrie, 988 Dechtiar et al., 988 Dechtiar and Nepszy, 988 Weller, 938 Dechtiar and Lawrie, 988 Jilek and Crites, 98 Dechtiar and Lawrie, 988 Dechtiar and Christie, 988 pinitectus sp. 5 (5/98) Bangham, 972 *, Lake rie;, Lake ichigan;, Lake uron;, Lake uperior; Ontario. t Percent infected (number of fish infected/number of fish examined). ± Larval stage. Parasite present but prevalence not given. Prevalence calculated from winter 984 sample. R, t. arys River; LC, Lake t. Clair; O, Lake 984; Dechtiar and Christie, 988). Cooper et al. (977) demonstrated that the prevalence of D. cotylophora in perch in the western basin of Lake rie decreased from , to 957, to 974. Rhabdochona spp. and pinitectus spp. infrequently occur in yellow perch from Lakes ichigan, uperior, and rie, and Lakes uperior, rie, and Ontario, respectively. Both genera are found in the intestine of several fish species and do little or no damage to their hosts. They utilize mayfly larvae and other arthropods as intermediate hosts. pecies not found as adults in the intestine of yellow perch are:. brachyurum, R. acus, Raphidascaris sp., Contracaecum sp., P. cylindracea,. tubifex, and ustrongylides sp. Larval. brachyurum have been reported in perch from 3 of the Great Lakes. Dechtiar and Lawrie (988) found. brachyurum and R. acus larvae in the liver of perch from Lake uperior and suggested that moderate to heavy liver damage occurred with iibrosis. imilarly, encysted. brachyurum caused liver damage to perch in Lake Ontario (Dechtiar and Christie, 988). Piscivorous fishes serve as definitive hosts for. brachyurum and Raphidascaris spp. Contracaecum spp. mature in piscivorous birds and mammals. The redworm nematode complex of yellow perch in the Great Lakes is composed of Camallanus oxycephalus, P. cylindracea, and. tubifex. The term "redworm" was coined by anglers asking the question, "What are these red worms in my fish?" (J. Crites, pers. comm.). Camallanus oxycephalus has been reported from yellow perch in 2 of the Great Lakes. tromberg and Crites (974) found that during July and August in Lake rie, female C. oxycephalus protrude from the anus of white bass, orone chrysops, and rupture, releasing infective larvae that are ingested by copepods. The life cycle is completed when infected copepods or small paratenic forage fish hosts are eaten by larger fish. Cooper et al. (977) found that the prevalence of C. oxycephalus in yellow perch in western Lake rie increased from , to 957, to 974. In the present study, P. cylindracea only occurred in yellow perch from aginaw Bay. Copepods are intermediate hosts for P. cylindracea (see olnar and Fernando, 975; Crites, 982). It is not known if P. cylindracea utilizes a trans- Copyright 2, The elminthological ociety of Washington

6 2 JOURNAL OF T LNTOLOGICAL OCITY OF WAINGTON, 66(2), JULY 999 port host in its life cycle. Philometra cylindracea has been found in perch from 3 of the Great Lakes, occurring unencysted in the body cavity. This nematode matures in, and is host-specific to, yellow perch, since it has been reported from no other fish species. ature females are about the same length as males (4 mm) or longer. Larvigerous females, which are delicate and have a thin transparent cuticle, may exceed mm in length and are easily broken during host necropsy. ustrongylides tubifex had significantly higher prevalences, mean intensities, and mean abundances in yellow perch from aginaw Bay than in those from Lake ichigan. Karmanova (968) and easures (988a, b) reported that tubificid oligochaetes serve as intermediate hosts for. tubifex. Although Brinkhurst (967) and chneider et al. (969) found large numbers of tubificids in aginaw Bay, aas and chaeffer (992) did not find tubificids in perch stomachs in aginaw Bay, and Rosinski et al. (997) found them to be infrequent. The lack of tubificids in stomachs is surprising, since perch from aginaw Bay and other areas of Lake uron are heavily infected. Tubificids have been found in the stomachs of yellow perch from Lake rie (J. Crites, pers. comm.), another lake where. tubifex commonly occurs. The difference in infection values of. tubifex between aginaw Bay and Lake ichigan may be explained by the large number of tubificids in the bay and by the small numbers of them in Lake ichigan. Piscivorous birds (e.g., mergansers, ergus merganser Linnaeus, 758; see easures, 988c) serve as definitive hosts for. tubifex, and differences in their numbers between these locations may also play a role in this difference. ustrongylides tubifex has been reported from yellow perch in 4 of the Great Lakes. It is infrequent in Lake ichigan, and the small number of perch examined from Lake uperior may not reflect its absence. Allison (966) reported perch from the Detroit River infected with. tubifex. Dechtiar and Christie (988) found. tubifex in several fish species from Lake Ontario and suggested that it caused damage to perch. This nematode is very common in yellow perch from Lake rie. Interestingly, Bangham and unter (939) did not report. tubifex in an extensive survey of parasites of Lake rie fishes, including 28 yellow perch. Bangham (972) was the first to report the occurrence of. tubifex in yellow perch collected in 957 from Lake rie. ustrongylides tubifex is pink to red in color and thicker than P. cylindracea. Larval. tubifex in fish intermediate hosts can reach cm in length. Cooper et al. (978) and Crites (982) demonstrated experimentally that. tubifex can be transferred when a small infected fish is eaten by a larger one. Crites (982) reported that. tubifex can live in capsules of host origin for at least.5 yr and demonstrated that the walls of the capsule have several different tissues and are furnished with capillaries. The larvae are nourished during their development and growth in these capsules. easures (988b) reported on the pathology of. tubifex in fishes, including the yellow perch. It appears that. tubifex infections in perch do not give rise to immunity, since larvae of different lengths were found in the same perch in the present study. Crites (982) showed that. tubifex and P. cylindracea were associated with weight loss in yellow perch. It is not known if this weight loss affected fecundity. In addition, P. cylindracea sometimes infected the ovaries of perch, but whether this impairs reproductive capacity was not determined. Allison (966) and alz (989) suggested these. tubifex and P. cylindracea play a role in reduced perch growth and high mortality. xcluding the almoniformes, percids are probably the most important group of fishes in the Great Lakes. Based on a review of the literature and the present study, it appears that nematodes do not greatly harm yellow perch, except for. tubifex and P. cylindracea, which commonly infect perch in aginaw Bay, other areas of Lake uron, and Lake rie (Allison, 966; Crites, 982; alz, 989; Rosinski et al., 997). These are Great Lakes areas where the catch rates of perch have declined (Francis et al., 996), but the direct effects of. tubifex and P. cylindracea on reducing the numbers of perch in these areas are not known. Acknowledgments I thank Dan Brazo, Indiana Department of Natural Resources, ichigan City, Indiana; Tom ccomish, Ball tate University, uncie, Indiana; Rob lliott and Doug Peterson, ichigan tate University, ast Lansing, ichigan; and Bob aas, Jack odge, Dave Fielder, and Larry hubel, ichigan Department of Natural Re- Copyright 2, The elminthological ociety of Washington

7 UZZALL NATOD OF YLLOW PRC 2 sources, t. Clemens and Alpena, ichigan, for providing the yellow perch; Bernadette ermann for technical assistance in 996; and John Crites for reviewing an early draft of the manuscript and sharing information on the nematodes of yellow perch in the Great Lakes. Literature Cited Allison, L. N The redworm (Philometra cylindraced) of yellow perch (ferca flavescens) in ichigan waters of the Great Lakes. ichigan Department of Conservation Research and Development Report 53, Institute for Fisheries Report pp. Amin, O elminth parasites of some southwestern Lake ichigan fishes. Proceedings of the elminthological ociety of Washington 44:2 27. Baker,. R. 984a. Redescription of Dichelyne (Cucullanellus) cotylophora (Ward and agath, 97) (Nematoda: Cucullanidae) parasitic in freshwater fishes of eastern North America. Canadian Journal of Zoology 62: b. On the biology of Dichelyne (Cucullanellus) cotylophora (Ward and agath, 97) (Nematoda: Cucullanidae) in perch (Perca flavescens) from Lake rie, Ontario. Canadian Journal of Zoology 62: Bangham, R. V Parasites of the spotted bass, icropterus pseudoalplites ubbs, and summary of parasites of smallmouth and largemouth bass from Ohio streams. Transactions of the American Fisheries ociety 63: tudies on fish parasites of Lake uron and anitoulin Island. American idland Naturalist 53: A resurvey of the fish parasites of western Lake rie. Bulletin of the Ohio Biological urvey 4:-23. -, and G. W. unter III tudies on fish parasites of Lake rie. Distribution studies. Zoologica 24: Brinkhurst, R. O The distribution of aquatic oligochaetes in aginaw Bay, Lake uron. Limnology and Oceanography 2: Cooper, C. L., R. R. Ashmead, and J. L. Crites Prevalence of certain endoparasitic helminths of the yellow perch from western Lake rie. Proceedings of the elminthological ociety of Washington 44:96., J. L. Crites, and D. J. prinkle-fastkie Population biology and behavior of larval iistrongylides tubifex (Nematoda: Dioctophymatida) in poikilothermous hosts. Journal of Parasitology 64:2-7. Crites, J. L Impact of the nematode parasite iistrongylides tubifex on yellow perch in Lake rie. U.. Department of Commerce Commercial Fisheries Research and Developmental Project D. Clear Technical Report pp. Dechtiar, A. O., and W. J. Christie urvey of the parasite fauna of Lake Ontario fishes, Great Lakes Fisheries Commission, Technical Report 5:66-6., J. J. Collins, and J. A. Reckahn urvey of the parasite fauna of Lake uron fishes, Great Lakes Fisheries Commission, Technical Report 5:9-48., and A.. Lawrie urvey of the parasite fauna of Lake uperior fishes, Great Lakes Fisheries Commission, Technical Report 5:-8., and. J. Nepszy urvey of the parasite fauna of selected fish species from Lake rie, Great Lakes Fisheries Commission, Technical Report 5: Francis, J. T.,. R. Robillard, and J.. arsden Yellow perch management in Lake ichigan: a multi-jurisdictional challenge. Fisheries 2: 8-2. aas, R. C., and J.. chaeffer Predator-prey and competitive interactions among walleye, yellow perch, and other forage fishes in aginaw Bay, Lake uron. ichigan Department of Natural Resources, Fisheries Division, Research Report pp. Jilek, R., and J. L. Crites. 98. Prevalence of pinitectus carolini oll, 928, and pinitectus gracilis Ward and agath, 96 (pirurida: Nematoda) in fishes from Lake rie. Canadian Journal of Zoology 59:4-42. Karmanova, Dioctophymidea of Animals and an and Diseases Caused by Them. Fundamentals of Nematology. Vol. 2. Academy of cience of the UR. Translated and published for U.. Department of Agriculture. Amerind Publishing, New Delhi, pp. easures, L. N. 988a. The development of iistrongylides tubifex (Nematoda: Dioctophymatoidea) in oligochaetes. Journal of Parasitology 74: b. pizootiology, pathology, and description of ustrongylides tubifex (Nematoda: Dioctophymatoidea) in fish. Canadian Journal of Zoology 68: c. The development and pathogenesis of ustrongylides tubifex (Nematoda: Dioctophymatoidea) in piscivorous birds. Canadian Journal of Zoology 66: olnar, K., and C.. Fernando orphology and development of Philometra cylindracea (Ward and agath, 96) (Nematoda: Philometridae). Journal of elminthology 49:9-24. uzzall, P elminths of fishes from the t. arys River, ichigan. Canadian Journal of Zoology 62: Pearse, A The parasites of lake fishes. Transactions of the Wisconsin Academy of ciences, Arts, and Letters 2:6-94. Rosinski, J. L., P.. uzzall, and R. C. aas Nematodes of yellow perch from aginaw Bay, Lake uron with emphasis on ustrongylides tubifex (Dioctophymatidae) and Philometra cylindracea (Philometridae). Journal of the elminthological ociety of Washington 64:96-. alz, R. J Factors influencing growth and survival of yellow perch from aginaw Bay, Lake Copyright 2, The elminthological ociety of Washington

8 JOURNAL OF T LNTOLOGICAL OCITY OF WAINGTON, 66(2), JULY 999 uron. ichigan Department of Natural Resourc- agath, 96 (Nematoda: Camallanidae). Journal es, Fisheries Division, Fisheries Research Report of Parasitology 6: pp. Tedla,., and C.. Fernando Observations chneider, J. C., F. C. ooper, and A.. Beeton. on the seasonal changes of the parasite fauna of 969. The distribution and abundance of benthic yellow perch (Perca flavescens) from the Bay of fauna in aginaw Bay, Lake uron. Proceedings uinte, Lake Ontario. Journal of the Fisheries Reof the 2th Conference of Great Lakes Research search Board of Canada 26: :8-9., and. 97. On the characterization of medley, ome parasitic nematodes from the parasite fauna of the yellow perch (Perca flu- Canadian fishes. Journal of elminthology 2: viatilis L.) in five lakes in southern Ontario, Can ada. elminthologia : tromberg, P. C., and J. L. Crites A new Ward,. B., and T. B. agath. 97 (dated 96). nematode Dichelyne bullocki sp. n. (Cucullanidae) Notes on some nematodes from freshwater fishes, from Fundulus heteroclitus (Linnaeus). Proceed- Journal of Parasitology 3: ings of the elminthological ociety of Washing- Weller, T Description of Rhabdochona oviton 39:3-34. filamenta n. sp. (Nematoda: Thelaziidae) with a, and The life cycle and devel- note on the life history. Journal of Parasitology opment of Camallanus oxycephalus Ward and 24: NOTIC FFCTIV WIT T JANUARY, 2 (VOL. 67, NO. ) IU, T JOURNAL OF T LNTOLOGICAL OCITY OF WAINGTON WILL B RNAD PARATIV PARAITOLOGY T FIRT VOLU NUBR WILL B "VOLU 67", INDICATING TAT PARATIV PARAITOLOGY WILL B "CINUING T JOURNAL OF T LNTOLOGICAL OCITY OF WAINGTON' YOUR BRIP IN T OCITY WILL CINU TO BRING YOUR ANNUAL IU OF PARATIV PARAITOLOGY Copyright 2, The elminthological ociety of Washington