|The SURG collection jar system|
|Syringe with end cut off. Note the remaining ridge to prevent the plunger from going too far.|
|Lid with flap, top.|
|Lid with flap, bottom.|
|Lid with flap, in place before adding the elastic cord hinge.|
|Flap attached to lid with elastic cord, keeping the hole closed.|
|Top view of lid. Simply suck up specimen with syringe, insert syringe into hole, and push plunger down to collect the specimen. The flap ensures the specimen cannot get out.|
|Lanyards made from shock cord.|
|Syringe with lanyard.|
|Jar with lanyard.||
This is a very handy and cheap set of biological sampling tools that you can make for yourself with minimal workshop facilities. The set works very well with sedentary and slow moving organisms from a few mm to about 20mm length, and in some cases larger. It will allow transfer of very delicate organisms to the collecting jar with low risk of damage.It has been extensively tested on nudibranchs during Terry Gosliner's recent collecting visit to Cape Town.
The design is public domain and anyone is free to use it for their own use or for sale to others, or to develop it further, though if it is improved we would appreciate pictures for our records.
There are no critical dimensions as long as everything fits together and the flap moves freely
I base the Jar on a commonly available honey jar sold at Plastics for Africa for about R2.50 (January 2008) and a 60ml disposable syringe from the local pharmacy at about R6.00 each (about U$1)
Buy several jars, of different volumes, as they are cheap, and the lids are interchangeable. This means that one collecting lid can be used with a series of jars.
The end of the syringe is simply cut off with a hacksaw. Cut it off beyond the parallel sides, so that a small amount of end remains, and file the opening to nearly the full diameter of the syringe bore. The small remaining flange will stop the plunger from falling out the bottom if you use it with excessive enthusiasm.
The lid of the jar is marked with a circle the diameter of the outside of the syringe using a fine felt tip marker, It is most convenient to offset this from the centre, but it should not be to close to the edge or the flap will foul the rim of the jar. This mark is used to drill and file out a hole through which the syringe will fit fairly loosely, but without too much gap, or specimens may be washed out through the gap.
A flop closure is made from stiff flat plastic or other suitable material, which is big enough to cover the hole and has a straight edge on one side that is about 6mm (1/4" from the edge of the hole when in place. The flap should cover the hole with a slight overlap the rest of the way round as can be seen from the photos. This allows a reliable closure to prevent loss of specimens. Drill a few 1mm to 1.5mm holes through the lid where it is not covered by the flap to allow more area for water to escape when inserting the specimen.
Two holes about 3mm (1/8") diameter are drilled through the flap and the lid, and the lid is secured with a loop of 3mm shock cord, tied and with the knot locked by a spot of waterproof glue.
Make a pair of lanyards from thin shock cord to tether the jar and syringe so they will not be lost if you let go of them. I like a wrist loop on each lanyard, but suit yourself. The lanyards will pull off at either end in case of an emergency.
Add a cheap plastic forceps and you have a very versatile collecting set for less than R20.00 (U$3.00)
Note that the jar is now vented, and will equalise and flood without attention at the start of the dive, but will also drain at the end of the dive if tilted. It is usually a good idea to carry an intact lid to seal the jar once out of the water, or even while in the water if a tricky exit is expected. An alternative is to put the jar in a plastic bag and seal the bag if the specimens may escape during a lid swap.
Notes on usage!
This equipment should only be used for legitimate scientific collection. Ensure that you have the necessary permits on site. Please do not collect for the sake of collecting!