Volunteers using standard scuba equipment conduct the Census surveys. Survey dives originate from shore and often involve long surface swims to reach the portion of the park that is to be surveyed. The EUWP is a shallow site and dive depths do not exceed 40 feet. Much of the diving is done at depths less than 30 feet, with dive depths varying with tidal height. Dive times are generally an hour or less. Each surveyor determines when and if they will dive, and is responsible for planning and carrying out the dives. The LNCG is not involved or responsible for the planning or execution of the dives.
Collecting the Census data is not a simple process. Low visibility conditions due to sediment or algae blooms can hinder finding egg masses and nest site ID Tags. Algae growth late in the season obscures egg masses and ID Tags. Dive gloves and cold hands hinder data recording. In addition, egg masses are generally tucked into cavities making it hard to take the three measurements. Guard fish seldom cooperate by holding still while they are measured. Aggressive guard fish are very hard to measure and can interfere with the measurements of the egg masses. The combination of these factors makes the measurement of the egg masses a very time consuming activity and limits the number of new egg masses that can be documented on one dive.
Simple tools are used to collect data about the nest site, the egg mass, and the guard fish. The materials used by the surveyors consist of:
A standardized data slate is used to record the data on egg masses and guard fish. This slate facilitates data collection by allowing the surveyor to circle appropriate nest and guard fish parameters and by providing spaces for dimensions to be written in. The slate provides a reminder of the data to be collected at each site and has a legend of the standard terms/attributes. A sheet of instructions is provided to the volunteer surveyorsto ensure consistent data collectedion. click here to see an enlarged view of the slate.
A measuring staff made from PVC pipe and graduated into 10 cm increments. The staff is used to estimate egg mass dimensions and guard fish lengths to the nearest 5 cm. Some surveyors add 5 cm tick marks between the 10 cm marks and may even add centimeter marks to a portion of the staff to aid with more precise measurements. Click here for a picture of a staff.
Seasonal nest identification tags are made of white plastic with the nest number and season marked in black with a permanent marker. The tags have a hole drilled in them to allow attachment to a convenient anchor point. Intended to last for one spawning season, the tags often persist for many seasons although they become encrusted with algae and barnacles. Old tags are left at the nest sites to help surveyors locate the sites and the tags for the current season.
When a new nest is discovered, the nest site is marked with an ID tag attached to a convenient point near the egg mass using a plastic wire tie. If additional egg masses are located at that nest site, the ID tag is marked to let surveyors know how many egg masses to search for during repeat observations of the site. At times, when a convenient attachment is not available, a short PVC stake is inserted in the sand and the tag affixed to the stake.
Underwater lights and/or magnifying glasses may be used to help observe the eggs.
Photographs and occasionally video are taken of the nests and guard fish to supplement the other data that has been collected.
Each Census dive requires a fair amount of effort to plan the dive, prepare the dive gear for the dive, travel to and from the EUWP, clean the dive gear after the dive, and transcribe the data into the data entry worksheet. One Census dive can easily require four hours or more of total effort.