The quantity of plankton nets you need for a study depends on many factors.
First of all, how many people will be using the plankton nets at the same time?
Are you doing more than one study in different bodies of water at the same time?
You'll be at sea for a long time, and extra nets could be useful in case of damage?
All these questions are important to ask before buying plankton nets.
A thumb rule that seems to work well is to always have a minimum of 2 units of the same plankton net for each location that will be surveying at the same time. For example, if you are conducting a study on 3 different vessels at 3 different locations with the same nets, we recommend 2 nets per vessel for a total of 6 plankton nets.
This way, each site has a replacement net in case of a tear during the study.
Again, this is the bare minimum and depends on your experience and risk tolerance.
Assuming that your vessel will be at sea for 5 weeks, you may want to obtain a few extra nets per vessel to ensure that there is no interruption in your study due to damaged plankton nets.
