JFStudy | HOTEL LAKE ADVISORY

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 and since then many other reports have come to light.

In 2022 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 for information so that we could publish a webpage about Jellyfish at: hotelakeadvisory.com. Over time Dr Lüskow outlined a research study of freshwater jellyfish that would require the help of local volunteers and happily six local Hotel Lake 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 2023 project involved 17 sorties out onto the lake to collect data and samples; these sorties dubbed “Stations” took place every 4 days. At each station volunteers conducted a number of measurements and sample-taking and associated processing for later analysis.

Six Volunteers

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

The following will give our readers an idea of the Station work and protocols: 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
(ALLOW TIME FOR TEMP DISPLAY TO STABILIZE AT EACH LEVEL).
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).

PLANKTON NET TOW PROCEDURE:

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

>>>>>>> ETHANOL TEST IS REQUIRED ON ODD-NUMBERED STATIONS:
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.

NOTE: ALL SAMPLE JARS AND TUBES MUST BE LABELLED 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.

In 2024 the UBC project was continued with the same volunteer group, now called Hotel Lake Stewards. The UBC stations were scheduled every 5 days and included several new tasks and changes to protocol, particularly with the processing and storage of samples for later analysis. In August a new horizontal catchment basket was introduced that permitted horizontal sweeps to determine the density of jellyfish in any particular area.

The basket has an opening 12 inches by 12 inches. It is dragged or pushed through the water using a powered dingy or float and the distance (more correctly, the volume of water that passes through the basket) is recorded by a propeller driven “odometer” inside the basket. At the end of each run, the number of jellyfish are counted and the volume of water can be determined using the odometer readings. Traversing large concentrations of jellyfish with this system produces interesting perspectives about jellyfish population-density.

Looking down into the “basket” ..... visible at the bottom are many jellyfish waiting to be counted.