Instructions for Volunteers
Overview of Collection Method
Megalopae collectors are made of three Tuffy Kitchen Scrubbers© pulled apart and stuffed into a length of black diamond mesh plastic bagging material with a rock in the end of the bag. The top of the collector is attached about 6 inches below a float. Hang the collector off a dock, float or a buoy. Once a week, retrieve the collector and rinse the megalops off of it by putting it in a collander or large piece of window screen and rinsing it with copious amounts of water. If you soak it in fresh water a few minutes, the larvae will fall off easier. Any megalops that have settled on the anchor, line and float should be noted, but excluded from the samples. Then, place the samples in a Ziplock © bag with a little air for cushioning and a label, and freeze it for collection and processing at a later date. Megalops settlement collection should begin during the first week of June and continue through the last week of September.
Depth Range
Ideally, the collectors should be suspended 6 inches below the surface at a depth of -6 to -9 feet Mean Lower Low Water (which is 0 tidal height). So, if the tide chart for your area say it is a + 6 foot tide at 12:00 noon, you want to put in around 12 to 15 feet of water. However, if your float is at a different tidal height, just note to approximate tidal height on the data form and the time you put it in. This range of depths was chosen so that the collectors don’t go dry at low tide but still remain within the depths known to historically have C. magister settlement.
Detailed Instructions
Deployment Methods
A variety of potential deployment methods are listed below. Chose the one that is most appropriate for your site. Illustrations of the following methods are included at the end of this document.
Dock or Float. This is the most convenient method. Attach a weight below the collector and a float above the collector so that the collector remains 6” below the water surface. Attach the float with a line to the dock. Make sure it is long enough to ensure that the collector remains in the water at low tide.
- Anchored Buoy Accessed by Boat. This method requires a boat to deploy and retrieve the collector. Connect a float to a 30’ line. Attach the collector bag 6” below the float. Attach a weight (2 oz line weight or mesh bag of rocks), 3’ below the collector. Then attach the end to a pier block with a bracket.
- Buoy from Shore. In locations where neither a dock nor a boat is available, the collector could be deployed to and retrieved from a buoy from shore, using a set-up similar to a clothesline. A ring is attached to the base of a stationary buoy and a long loop of sinking line is strung from shore, through the ring and back. The collector (float 6” above. weight 6” below) can be attached to the line, and pulled out, then back the next day. This method may be subject to fouling or tangling.
- Collectors on the beach. Megalopae settlement data collected from beaches at low tide could still provide valuable additional information to this study especially where near-shore collection is not feasible. Although its use in the analysis would need to be qualified because of the shorter time in the water. The same float / collector/ weight / anchor set up could be used. Time of deployment and retrieval would be based on the lowest tide each week.
- Opportunistic observations. Any chance observation of megalopae settlement on the beach or floating surfaces is valuable information and should be documented. Samples can be collected by sieving sediment on site. Sieves and additional instructions will be available in each area. Contact the Local Volunteer Coordinator, or the Project Manager.
Equipment List
The following equipment and supplies are necessary to collect samples:
- Line
- Buoy
- Artificial megalopae collector (mesh bag with 3 Tuffy © Scrubbers pulled apart)
- Mesh bag for rock weight or 10 oz weight
- A hanging or anchoring system
- Sample Labels
- Ziplock © bags
- Data Forms
Training
Training sessions will be held in each area. You will be notified when they have been scheduled.
Record Keeping
All field activities will be recorded on Megalopae Collection Data Forms which will be supplied with the collection equipment. The data forms will provide a record of observations, and measurements taken during the collection activities. The data forms are intended to provide sufficient data and observations to enable the volunteer collector to reconstruct events that occurred during the project. The data forms will contain the following information:
- Date and military time of sample collection
- Weather conditions, including temperature
- The location number and name (e.g. Marine Science Center Pier)
- Location of sampling point (lat-long coordinates in decimal degrees or street address)
- Sample identification number (see below)
- Water temperature
- Depth of sample location
- Field observations will include any procedural steps that deviate from those outlined here and any physical observances (e.g. sediment type, presence of oil sheens on water).
Sample Identification
All samples collected will be labeled with a unique identification code consisting of the location code and the date. For example: PTMSC- 060109, would indicate Port Townsend Marine Science Center, June 1, 2009. The code for each location will be depicted on the web based map.
Sample Packaging and Pick up
Samples will be frozen in ziplock bags containing a little air (for cushioning) and the sample label. Data forms and samples will be picked up at the end of each month of sampling by the Local Volunteer Coordinator or their designee. Logistics and freezer storage will be arraigned in each area.