Observations on the glochidia of Lampsilis radiata (Gmelin) infesting yellow perch, Perca flavescens (Mitchill) in the Bay of Quinte, Lake Ontario

Abstract

Analysis of incidence and intensity of infestation of yellow perch, Perca flavescens (Mitchill), by the glochidia of Lampsilis radiata from weekly samples from May to September and single samples in October and November indicate that the two subspecies, Lampsilis radiata radiata and Lampsilis radiata siliquoidea, shed their glochidia in late spring and throughout the summer in the Bay of Quinte, Lake Ontario. Smaller fish are more heavily infested with these glochidia than larger ones. About 50% of the preparasitic glochidia of Lampsilis radiata siliquoidea survived for 12, 70, and 120 h at 20°, 12°, and 10 °C respectively. The parasitic period of the glochidia of L. r. siliquoidea on yellow perch under experimental conditions was 50 days at 15 °C from the May infestation. Yellow perch carried the glochidia for a longer period from an August infestation. All the glochidia recovered 50 days after infestation, both from May and August infestations, had undergone metamorphosis. There was no difference in the degrees of infestation of the different species of fish used in our experiments. Pumpkinseed, Lepomis gibbosus (Linnaeus); rock bass, Ambloplites rupestris (Rafinesque); and white perch, Roccus americanus (Gmelin) lost their infestations in a week. Presumably no metamorphosis took place under these conditions. Black crappie, Pomoxis nigromaculatus (LeSueur); largemouth bass, Micropterus salmoides (Lacepede), smallmouth bass, M. dolomieui Lacepede: and yellow perch carried the infestation till they were killed 20 days later. There was no relationship between the numbers of glochidia (Lampsilis radiata) and copepods, (Ergasilus confusus Bere) on naturally infested yellow perch, nor on rock bass, smallmouth bass, and pumpkinseed which harbored Ergasilus spp. naturally and which were infested with the glochidia of L. r. siliquoidea experimentally.