Calling Scientific Divers

[bubbleblowindude]

Regarding the relocation of a specific dive site for the purpose of conducting a survey, is there a specific technique (s) to do so?
(Other than the obvious GPS / marker buoy) I'm not looking for good ideas or suggestions, rather accepted scientific practice on the matter.
Thanx!

 

[bubbleblowindude]

relocation of a specific "underwater" area.

 

[udtfire]

if your looking to move a site and reproduce it somewhere else the grid system is the only way i know of to do it can you give more details

 

[bubbleblowindude]

i would be interested in that, as well as a method of simply finding the same spot the next day.
thanx!

 

[smellzlikefish]

I've done a lot of surveying work before, and many of the biologists I know use stakes driven into the substrate or tie ribbon around fingers of coral or rocks sticking up. That way you can use the GPS to get close, then scour the bottom for your markings, then define your transect/grid by way of compass. As far as laying transects, if you are doing the survey two days in a row or close in succession, you could leave the transect down there hoping nobody else picks it up. Make sure it is securely fastened on the bottom (tied around rocks or rocks placed on the line) and clean everything up when you are done.

 

[DennisS]

I've seen biological survey counts done with the donut method, instead of a grid. A stake is driven in and a line attached with markers every so many meters. There is a fairly good distance between the stake and the first marker. It kind of nullifies "this is a good spot" placement of the stake bias. A transect (transit?)measures the angles. The weight hanging down from the tripod is over the reference point.

The line is unreeled to the first marker for the count and one circuit around the stake, it's then rolled out to the second marker, another circuit-another count etc. An advantage is that you don't have to lay down a grid. Everything has a measurement and an angle related to the reference point, ie 110 degrees, 14 meters.

Here's are some survey procedures for coral reefs

http://www.epa.gov/bioiweb1/coral/coral_biocriteria.html

As far as relocating, GPS and a marker in the bottom gets you back to the survey site year after year.