EGG DISTRIBUTION AND SPAWNING HABITAT OF NORTHERN PIKE AND MUSKELLUNGE IN A ST-LAWRENCE-RIVER MARSH, NEW-YORK

Coexistence of northern pike Esox lucius and muskellunge Esox masquino ngy in the Niagara and St. Lawrence rivers has been hypothesized to de pend on segregation during spawning. However, large overlap in the use of spawning areas by these two species occurs in the Thousand Islands section of the upper St. Lawrence River. In this study, egg collectio ns in Point Marguerite Marsh in the upper river revealed a partial tem poral and spatial overlap in egg deposition by northern pike and muske llunge. Northern pike began spawning earlier but overlapped with muske llunge spawning for 2 weeks, May 13-27. Northern pike eggs were collec ted over a larger area than muskellunge eggs and at all locations wher e muskellunge eggs were collected. Both species deposited eggs over th ree dominant genera of vegetation: pondweeds Potamogeton, duckweeds Le mna, and stonewort Chara. Northern pike spawned over a wider range of water depths (0.5-2.6 m) than muskellunge (0.8-1.5 m) and selected hab itats with denser, taller vegetative cover. The temporal and spatial o verlap of northern pike and muskellunge egg deposition suggests that m echanisms other than spawning segregation permit these two species to coexist in the St. Lawrence River.