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UBC Study of Freshwater Jellyfish

Impacts in BC

Jellyfish sightings in local lakes date back to 2001.  In 2020 Harbour Spiel published an article about the discovery and study of hydromedusae, freshwater jellyfish in BC.  A subsequent article by Stephan Labbé appeared in the June 14, 2022 edition of Coast Reporter.


At that time we took great interest in these articles because we were frequently seeing these jellyfish in Hotel Lake during the summer months. This motivated us to contact Dr. Florian Lüskow at UBC after which we published a webpage about Jellyfish at: Over time Dr Lüskow outlined a research study of freshwater jellyfish that would require the help of local volunteers and happily six volunteers came forward to assist in the summer of 2023.


This project began with Dr. Lüskow and Professor Pakhomov visiting Hotel Lake to provide training to the 6 volunteers.  The project involves 17 sorties out onto the lake to collect data and samples; these sorties dubbed “Stations” take place every 4 days. At each station volunteers conduct a number of measurements and sample-taking and associated processing for later analysis.

The last station, Station 17, was done on September 7, 2023.  The next day, Dr. Lüskow, Professor Pakhomov and other scientists from UBC visited Hotel Lake to wrap-up and to administrate final testing.  Sensing considerable local interest in jellyfish, Dr. Lüskow agreed to speak on the subject:  “Freshwater Jellyfish in British Columbia & Beyond – knowledge gaps and current progress.”  This presentation will take place on September 9, 2023 at Sarah Wray Hall in Garden Bay at 2:00pm.

The preparation of water for use in pressurized or squeeze bottles, during sampling, can be done on station or prior to departure as the photo (below) shows.  Water is obtained from the lake and filtered into the two bottles through the 125um sieve.


Protocols and Procedures

1.    Bottom depth determination with a slack line from Secchi disk. (record depth in notebook)


2.    Secchi depth measurement​.(record depth in notebook)


3.    Temperature profile with YSI sonde

  • Take a measurement during descent every 0.5 m


  • CONTINUE until half a metre above the lake floor

  • Note depths and temperature in notebook


4.    Water properties​

Rinse bucket with surface water, then take a water sample from the lake.

  • Chlorophyll

    • Rinse syringe twice with lake water from bucket.

    • Filter 60 mL of lake water through top-syringe filter for chlorophyll twice (total: 120 mL)

    • Wrap the top-syringe filter in tin foil

    • Move the filter into a pre-labelled test tube (wrap test tube with tin foil) store in freezer (after returning to land)


4b.  Water Properties, Nutrients

  • Rinse test tube three times with water from the syringe

  • Filter water from syringe into test tube and fill to 13 mL

  • Repeat this process for a second test tube

  • Label the test tubes

  • After returning to land, ensure test tubes are labeled and then store in freezer.


Introductory note:

The usual plankton sampling consists of TWO net tows that end up in the same sampling jar and are fixed with formalin.  On every second sampling mission (1st Station, 3rd, 5th, etc), you will take ONE additional net tow for ethanol. The ethanol sample requires only ONE net tow.


5.    Zooplankton sampling (net tow)

  • Filter water with sieve into pressurized spray and squirt bottles (this may be done prior to departure).


  • Lower the plankton net vertically to 1 m above the lake floor

  • Bring the plankton net up to the surface at 0.5 m/s (for the 10 m distance, this should take 20 s)

  • Use pressurized spray-bottle-wand, working down the exterior of the net, to wash plankton down into the net end.

  • Unscrew net end, wash content onto the 125 um sieve with squirt bottle

  • Use squirt bottle and lab spoon to transfer net content into pre-labelled sample jar (230 mL)

  • Repeat the net tow procedure and add contents to the same sample jar.

  • Add filtered water to approximately 90 mL (about half way up the jar)

  • WEAR NITRIL GLOVES, Add test tube with formalin (10 mL).

  • Seal sample jar, then invert sample jar  gently several times and then seal with parafilm


  • Repeat net tow procedure once only

  • Place contents in a second sample jar ( pre-labelled incl: "Ethanol') and fill the jar with ethanol (95%) up to the "shoulder", i.e. the point at which the jar narrows down at the top; seal sample jar.

  • Invert plankton sample jar gently several times and then seal with parafilm


Photos below show (in sequence): On all stations, the addition of formalin from the small tube into the specimin jar. Next, on odd-numbered stations, the addition of ethanol from the large jug into a second jar. Next, the subsequent sealing of jars with parafilm. Note: all specimin jars and tubes should be marked with STATION NO.  and  DATE. 


After the sampling, you should have:

  • Bottom depth and Secchi depth, temperature measurements for every half metre and other weather and time info noted in Station Log Book (take photo of Station page and send to Florian).

  • 1 filter in test tube, wrapped in foil (to be stored in freezer) - for chlorophyll

  • 2 test tubes (to be stored in freezer) - for nutrients

  • 1 sample jar with plankton in 3.7% formalin (stored at room temperature in the dark)

  • (ON ODD NUMBER STATIONS),  a second sample jar with plankton in 95% ethanol (stored at room temperature in the dark)


Additional notes:


The "plastic heads" of the syringe filter shall be kept and reused once you run out of "prepared filter heads". No further treatment is required.


The empty formalin tubes with screw caps in place can be collected as they contain retaining formalin. This is still toxic and do not dispose in your house garbage.  These will be collected by UBC and disposed of properly.


A pleasant surprise was a visit by Sina Shoeybi, a biologist from Toronto, who took a week off to fly to Vancouver, visit Florian at UBC and then drive up to Hotel Lake to look for and see our freshwater jellyfish and, after doing that for two days, he went south to Trout Lake to do a thorough search there as well.

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