- After completion of the net tow, concentrate the plankton sample into the cod end by washing down the net with the deck seawater hose (DO NOT use fresh water). Be sure to spray the net from the outside to minimize damage of the delicate plankton in the sample.
- Once the sample is concentrated into the cod end, use a screwdriver to loosen the hose clamp. Give the cod end a tug to detach it from the PVC coupler. If the sample will overflow the cod-end when removing it from the coupler, grab a bucket and remove the sample over the bucket. Make sure to wash down any sample remaining in the net into the bucket as all our plankton tows are quantitative (no sample can be lost).
- Take the cod end into the preservation sink area. Remove the appropriate jar from the sample box (pint jar for Pairovet and Manta, quart jar for Bongo; all boxes are labeled accordingly) and set it into the sink rack. Be sure the begin-tow time is written on both inside & outside labels, using pencil for inside and Sharpie for outside. Peel off the outside label backing and stick to jar lid. Put the inside label into jar.
- Using the filtered seawater hose, concentrate the plankton into the bottom of the cod end. It is ok to gently spray the inside of the cod end at this point but not so hard you will damage the organisms. Once the plankton are sufficiently concentrated towards the bottom, invert the cod end into the draining sock (a wooden dowel helps). There are 2 different mesh sizes of draining sock, always make sure you use the appropriate size mesh for the sample you are preserving (.150 for Pairovet samples, .333 for Manta or Bongo). The draining sock is helpful because it allows you to use as much seawater as necessary to thoroughly rinse the cod end. Gently spray the cod end with enough seawater to remove all the plankton clinging to it. It is very important not to lose any part of the sample or it will no longer be quantitative. Large pieces of kelp or grass or anything obviously not plankton can be rinsed off thoroughly and discarded at this point. Using a spoon, transfer the plankton into the jar. Rinse the spoon into the draining sock and then invert the draining sock into the jar. Wash down any of the remaining plankton into the jar with the rest of the sample, filling the jar with seawater to just below the shoulder.
- Wear eye protection. Add a squirt of supersaturated sodium borate to the sample for buffering purposes. Formalin is slightly acidic so the borate raises the pH of the sample to neutral. Add 10 cc. to pint jars, 20 cc. to quart jars. The syringe is usually marked with a “P” for Pint and a “Q” for Quart.
- To add full strength formalin, unclip the plastic binder attached to the tygon tubing of the formalin rig to allow for flow. Hold the 60 cc. syringe firmly and pull out the stopper to the desired amount (25 cc. for Pint and 50 cc. for Quart). Re-clip the plastic binder and dispense the formalin into the jar. Be careful not to spill any or push so hard the formalin squirts out the back of the syringe. Formalin is very caustic and extra care should be taken when dispensing it. If you have any allergies to formalin then you should not help with this step of the preservation process.
- After the formalin is added, secure the lid tightly and invert the jar a few times to ensure proper mixing of sample & chemicals. Return the sample jar back to the correctly labeled box.
- Rinse the cod end with the deck seawater hose and invert it back to the original position. Reattach the cod end to the coupler and tighten the hose clamp securely.
Thank you for all your help, it’s greatly appreciated !!