04-23-2018 Council Packet - Laserfiche WebLink

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Ms. Cassy Ordway Long Lake Creek Subwatershed Partnership - Proposal Page 2 One (1) electrofishing survey will be completed in the spring of 2018. During this survey, we will measure and weigh a subsample of carp to be used for calculating biomass and length -frequency. Seven (7) carp will be implanted with high frequency radio transmitters. The reaming carp will be marked with a fin clip for developing the mark -recapture population estimate. Radio tagged carp will be tracked —1-2 weeks after surgical implant via telemetry surveys to document position within the subwatershed. We anticipate completing four (4) spring/summer telemetry surveys. Radio tag locations will be recorded and added to an internal geodatabase used to produce survey maps for each telemetry survey. Long Lake has a number of obstructions on the bottom of the lake that currently prevent the lake from being seined. To address this, JR Commercial Fish proposes to remove the obstructions. This will involve pulling a net through the areas where carp are assumed to aggregate. The net will allow commercial fishing crews to locate the obstructions. Once obstructions are located, a diver will attach a line to each of the obstructions and the obstruction will be pulled from the lake. WSB will provide an update to the partnership on where, what type, and how many obstructions were located before being removed. Under this proposal, it is assumed that the City of Long Lake will dispose of the obstructions. We anticipate this work being completed in late spring/early summer 2018. Starting in late summer/fall 2018, we will complete three (3) electrofishing surveys on Long Lake. These surveys will allow us to create a catch per unit effort (CPUE) model to calculate the number of individual adult carp per acre, carp biomass per acre, and total biomass for Long Lake. Additional carp will be measured for length, weighed, fin clipped, released, and the remaining three (3) radio tags implanted. Three surveys should provide a reliable estimate over a range of environmental conditions and calendar period. Telemetry surveys will be resumed in late fall/early winter 2018 to identify carp aggregations. This data will be provided to commercial fishing crews to facilitate a removal of a portion of the carp biomass. After obstructions are removed, the carp population quantified, and carp are surgically implanted, WSB staff will work with JR Commercial Fish to identify when and where carp aggregations occur. This will be accomplished through a series of telemetry surveys. Under this proposal, JR Commercial Fish will complete one under ice or open water removal attempt using a large seine net. Additional carp removals may be completed based on the percentage of biomass removed in the first removal. This percentage will be calculated using the population estimate developed as part of this proposal. We will require authorization from the City of Long Lake and the Long Lake Creek Subwatershed Partnership for additional removals. Carp ageing has been added to provide additional data on carp population metrics and develop an initial understanding of the carp age structure in Long Lake. Budgetary constraints limit the ability to collect a large enough subsample to develop a holistic age structure for the Long Lake carp population, but under this proposal we will collect ageing structures (otoliths) from a subsample of 60 adult carp. This samples will be cross sectioned, mounted, and read. To reduce gear bias and provide a more representative sample, we may collect portions of the subsample during spring electrofishing, fall electrofishing, and netting operations. This ageing data can be paired with length frequency data to determine recruitment intervals and specific age classes associated with peaks identified in length -frequency data. A final report will be drafted and submitted after carp removals and subsequent data collection have been completed. The report will include data from 2018 telemetry surveys, carp metric data, population/biomass estimates, biomass removal totals, and recommendations.