Quantitative Freshwater Mussel Survey Date Prepared: 11/20/2017

Transcription

1 PARTNERSHIP FOR THE DELAWARE ESTUARY Science Group Quantitative Freshwater Mussel Survey Date Prepared: 11/20/2017 Prepared By: Kurt Cheng Suggested Citation: Cheng, K Quantitative Freshwater Mussel Survey. Partnership for the Delaware Estuary. PDE FMRP Method No pp. PDE-FMRP-Method (11/20/2017) Page 1

2 Quantitative Freshwater Mussel Survey Partnership for the Delaware Estuary (PDE) Freshwater Mussel Recovery Program Method Kurt Cheng Description This Freshwater Mussel Recovery Program Method (FMRPM) describes the general conduct of a quantitative freshwater mussel survey. This type of survey is time intensive and is generally set up based on qualitative survey results or other prior knowledge of a site. Surveyors sample mussels within fixed sample plots along transects. Live mussels are enumerated, identified, and measured. The goal of a quantitative survey is to gather robust data on freshwater mussel population density and species assemblage within a fixed area. Summary of Approach The general approach is to survey an area of interest for mussels using standard protocols along transects and fixed plots. Transects are equidistant and run perpendicular to a shoreline. Plots are placed along transects based on water depth. Surveys are time-intensive and plots are completely excavated to remove every mussel within a one meter squared quadrat. Mussels are enumerated, identified, and measured for shell length prior to placement back into their habitat. Surveyors generally search for mussels tactilely, visually, or utilize tools such as a scoop or small screen sieve to detect juveniles. Equipment Small screen sieves (<5 mm opening) Scoops One square meter quadrats PVC marking posts with hooks Survey flags 100 meter transect tapes Diving buoys Dive belt with weights Waders Snorkels Diving Masks Swim fins Wetsuits Flotation Devices Anchor weights Tethers Datasheets Pens Clipboard Camera Freshwater Mussel Guide Handheld GPS unit Collection Bags Scientific Collection Permit Procedures 1. Permitting In order to properly survey freshwater mussels, it is necessary to remove mussels from their habitat. This is considered a collection and as such, a scientific collection permit is required. Refer to FMRPM-01. PDE-FMRP-Method (11/20/2017) Page 2

3 2. Site Selection To conduct a quantitative survey, identify an area to be surveyed. This is generally done through other surveys, local knowledge, and is coordinated through the particular state s permitting agency. 2.1 Site Characterization Tools such as stream gages managed by the United States Geological Survey (USGS) may be consulted for information such as water conditions which may impact survey efforts. Examples of site characteristics that influence a survey include salinity (freshwater mussels will not occur in brackish waters), water level, and feasibility of mussel detection. Mussel detection during a survey is influenced by water depth, shoreline development (e.g. landscaped, hard structure, restricted access), and unsafe conditions that prohibit sampling (swift current, water depth, field hazards). 3. Quantitative Survey 3.1 Survey Safety In flowing waters, snorkelers shall have one spotter at the minimum for safety. In tidal waters, snorkel surveys shall be limited to ebb tides and utilize a safety vessel. Surveyors shall stay in shallow areas no deeper than their own height and don buoyant wetsuits with swim fins. If needed, place dive buoys surrounding the survey area for safety. 3.2 Site Setup Set up survey transects using PVC poles or survey flags on shore and at the furthest transect point. Use a spotter on land and additional poles/flags to ensure a straight transect. Sample plots are determined based on depth (at ebb tide if applicable) and marked using poles or flags. Use a transect tape to measure distance between each transect and positions of plots along transects. The number of transects and plots shall be tailored to the site. 3.3 Mussel Sampling Surveyors may snorkel in deeper waters, or wade in shallow waters. Surveyors will employ the most appropriate method for each plot. To aid in survey efficiency, surveyors may use a floating device (e.g. float tube) to contain survey materials such as collection bags, additional survey markers, scoops, or snorkel gear. Place a one meter squared quadrat so the plot marker touches the bottom right corner of quadrat (facing away from shore). Placement of quadrats shall be consistent among all plots and surveyors. Collect all mussels within the quadrat using least destructive methods (e.g. PDE-FMRP-Method (11/20/2017) Page 3

4 hand collection, scoops and sieves if needed). Transport all mussels in collection bags with ID tags to shore for processing. 3.4 Data Collection All live mussels shall be identified, photographed, measured for shell length (FMRP-10), and returned to their habitat. Dead shells may be collected as voucher specimens if surveyors are permitted to do so through their scientific collection permit. General survey results are expressed as an average population density in units of mussels / m2, calculated by the following equation: Average Mussel Population Density=( # of Mussels Found)/(# of Square Meter Plots) Survey plot locations are recorded using a GPS unit for future mapping purposes. 3.4 Additional Site Characterization Surveyors should note observed physical habitat qualities to help inform future restoration work following FMRPM-02. Water quality monitoring may be incorporated following FMRPM-04. PDE-FMRP-Method (11/20/2017) Page 4

5 Appendix Freshwater Mussels: QUANTITATIVE SURVEY Project Name: Date: Site: Waypoint / Sub-site: Personnel: Mussel Species Abbreviation Key (Other mussels shall be written in full) AI Anodonta implicata LC Lampsilis cariosa LO Leptodea ochracea NM No Mussels Found EC Elliptio complanata LN Ligumia nasuta PC Pyganodon cataracta UN Unknown Mussel Survey Results Plot ID Species Length (mm) Notes? Plot ID Species Length (mm) Notes? NOTES (coordinates of specimens, mussel habitat; depiction of area): PDE-FMRP-Method (11/20/2017) Page 5