Development of a rapid surveillance method for annual mayfly surveys in Lake Erie

Objectives. 1. To develop and test a survey approach that will permit many square meters of lake bottom to be examined within minutes, thereby greatly increasing the ability to detect the presence and estimate the abundance of Hexagenia nymphs compared to conventional sediment grab sampling. Abstract: A remotely operated vehicle (ROV) was employed in August 2  3 to survey hundreds of square meters of the bottom of Lake Erie at several stations. The objective was to test the feasibility of using a ROV to detect and quantify the abundance of Hexagenia (burrowing mayfly) nymphs in areas where they are present but in such low numbers that typical grab sampling methods are ineffective. Analysis of videotapes of the lake bottom, ground-truthed with Ponar grab samples of the sediment, indicates that the ROV effectively detects the presence of Hexagenia burrow holes in areas where grab samples have a small chance of sampling the nymphs. Analysis of the quantitative value of the videotapes is continuing.