Najas minor removal from Lake Arrowhead

Surveyors: Debbie Broderick (BR-4119) and Dale Schultz (SC-4118)


Today we finished up our removal of N. minor from Lake Arrowhead.


We spent at least 2 hours per day in the water, Thursday through Saturday, initially removing the large clump we had avoided before, and then removing additional plants as we found them. We knew of one large plant when we set out on Saturday, but found another 21, and removed them all. A lower water level and an absence of boats made it easier to find additional plants.


On Thursday October 8th, we found that the largest plants had fallen over, but were still intact, and we suggest that harvesting be completed before October each year.


We are not aware of any more plants in the lake, but we stress that we have not snorkeled everywhere where they are likely to be.


We bought a waterproof camera in order to film the technique we have developed for removing the plants and we are in the process of putting the video together. We believe that the low-tech method will work well in late summer when water temperatures are more conducive to swimming.


The video will be shared when ready. Update: https://youtu.be/wCjYW4SpJdg


Side note

We believe that the recurved and serrated leaves of N. minor are mechanisms to increase the chances of fragments sticking to things in order to aid the dispersal of the fragments and hence, the seeds. Tiny fragments floating in the water resemble tiny grappling hooks. Fragments stick to things very easily. This, coupled with the strategy of the whole plant fragmenting in the fall represents an extremely efficient strategy for seed dispersal.