Bryozoan
(Pectinatella magnifica)
We start with a question; have you ever seen one of these in Hotel Lake? Please let us know if you have. We ask this question because it is possible that they are already in the lake. Please read on, its a great story. ​​
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Introduction
In October of 2025, we published our new webpage about Zooplankton. We knew that was just a beginning and that we would likely find more tiny creatures living in Hotel Lake.
Just a few days later, on November 9, 2025, while doing UBC station work on Hotel Lake, we brought up four plankton-net-pulls and found ourselves staring into the sample jar and seeing a number of very tiny darkish dots suspended with the otherwise familiar mix of Cladocerans (Daphnia), water mites and other plankton. We took video and photos and consulted with UBC. The answer was almost instantaneous because they had seen the same dots a year earlier in samples taken from Hotel Lake and identified them as Bryozoan, Pectinatella magnifica statoblasts. The statoblasts can be seen below.
So the dark dots we were seeing were statoblasts, which is to say they are dormant, asexual- reproductive-structures produced by freshwater bryozoans. And, while these statoblasts seemed to visually fit the definition of zooplankton, we found out they were not. Instead, from various sources, we learned that role of statoblasts is to perpetuate Bryozoans which have inhabited the earth for over 470 million years.
Often characterized as “life-boats”, statoblasts function like a seed or spore and are critical for the survival and dispersal of the highly interesting Bryozoan Pectinatella magnifica which is the subject of this web page.
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We will start with the relatively massive Bryozoan and later return with more information about the Statoblasts.
Bryozoan, Pectinatella magnifica
Bryozoans are microscopic aquatic invertebrates called zooids that, from summer to fall, congregate and live together and form sedentary colonies on the surface of a gelatinous mass.
Bryozoan, Pectinatella magnifica, that have been seen recently, (2017-2018) in BC, are large gelatinous masses covered with rosette-shaped colonies that are connected by gelatinous secretions to an underlying gelatinous mass. In essence, when they assemble together and form large colonies, they make their own gelatinous substrate (mass). The outer surface colourations of a Bryozoan, Pectinatella magnifica, mass can range from transparent-to-brownish purple.
These Bryozoan colonies are usually attached to aquatic plants or solid substrates (shells, rocks, tree limbs and ropes) and are usually found in shallow water.
Zooids
Zooids
Zooids are tiny invertebrates a mere half-milimeter (0.02 inches) wide and barely visible to the naked eye. They have a specialized horseshoe-shaped tentacle-like limbs called a lophophore with a crown of tentacles that filter food, mainly plankton, diatoms, algae and organic matter, from the surrounding water. The mouth is at the base of the tentacles and is encircled with red pigment. Zooids are preyed upon by worms, small crustaceans and small gastropods.
Zooids, have a brief larval stage, during which they use their lophophores to move and swim around freely until they secure themselves to a solid substrate. Once secure, they begin to produce a colony asexually through budding. They are also capable of sexual reproduction and produce free swimming larvae. The result is that these colonies can grow thousands of individual zooids very quickly.
As zooids reproduce they use a special protein to attach together and form various shaped patches which are often repeated rosette-like patches or colonies on the surface of a squishy gelatinous base. Zooids secrete gelatinous material to create a protective environment for zooid growth.
Often these colonies have a lumpy surface texture that clearly accentuates individual rosettes of multiple zooids. These large gelatinous masses, covered with many hundreds of individual zooid nodes are often found in shallow freshwater environments. Colonies, when they attract human attention are loosely referred to as “Bryozoans.”
Asexual reproduction involves the prolific production of asexual statoblasts and floatoblasts, tiny capsules designed to survive severe temperature changes and ensure the ongoing survival of the colony.
Zooids are known to require water temperatures higher than 15.5°C to survive, and up to now, they were quite common in warmer (southern) areas of North America. It is when the water temperature cools down below 16°C in the Fall that the annual cycle ends with the disintegration of the colony.
On November 9, 2025 we measured the entire water column in Hotel Lake: it was 11°C
As the zooids drop off and die they decompose and release their statoblasts which contain dormant germinal tissue essential for the continuation of the species. As the zooids drop off they leave behind the entire gelatinous mass which, being mostly composed of water, will gradually break down and be absorbed by the fresh-water body. On November 9, 2025 we saw multiple statoblasts in Hotel Lake (see below)
Statoblasts and Floatoblasts
Getting back to the statoblasts that we photographed in Hotel Lake on November 9, 2025 when the entire water column, from surface to 9 metres, was 11°C, we now have a much clearer idea of what we were seeing.
The statoblasts we saw were in their aquatic-storage phase. They appeared to be inert and simply suspended in the water column. All around them were highly animated planktonic lifeforms. The statoblasts first appeared as dark spots but closer magnification revealed a reddish colouration in the circular disk and slender, evenly-spaced hooked spines radiating from the outside edges. Although surrounded by active plankton, the statoblasts were not feeding or moving. Some sources differentiate between statoblasts and floatoblasts. but the differences are not clearly delineted except it is implied that some statoblasts may float which is certainly the case with the ones we saw in Hotel Lake.
The statoblasts, in the 11°C water that we were sampling were essentially a highly-protective, bivalve-like shell made of chitin, inside of which were dormant germinal tissue (cells). Thus protected, the dormant cells can survive freezing or drying out for long periods of time. Thus, statoblasts are a durable component of an asexual reproductive and dispersal strategy that guarantees the future of new colonies.
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When warm weather and water conditions return, the protective shell will open, and the living cells inside will germinate as individual zooids destined to form a new bryozoan colony. This asexual reproduction, allows the genetic lineage of a freshwater bryozoan colony to persist through unfavourable seasons and conditions and, in some cases, to disperse to new locations.
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The hooked spines around the edge of the statoblast are believed to help the statoblasts attach to the plumage of waterfowl, floating vegetation, or other animals.
Over the summer months, some statoblasts may detach from their original colony. Statoblasts, once free, may float around in currents and settle on underwater structures or the lake bottom or otherwise hitch a ride from waterfowl or other aquatic species to be released in new locations. Statoblasts can also survive being eaten by fish or waterfowl which broadens their dispersal to within water bodies and even through the air.
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In the Fall, when water temperatures drop the Bryozoan colony’s zooids die and fall off. All that remains is the centre of the colony, a slimy, transparent, gelatinous mass which is most likely to have a number of dark dots clinging to surface. These are the remaining un-deployed statoblasts.
So if you wondered how they survived for 470-480 million years, well.... this is how!
Bryzoan Life Cycle
From summer to fall, zooids live, reproduce and grow on the outer layer of the Bryozoan mass. Zooids create and secrete the gelatinous material that is the gelatinous structure at the centre of their colony.
They use their tentacle-like limbs called lophophores with, ciliated tentacles funnelled to create either a current or, by flicking the tentacles, to drive food (algae, diatoms and organic material) down the tentacles and into their mouths.​ Zooids can multiply sexually using ovaries and testes; they can also reproduce asexually. At the end of summer, statoblasts (cells encased by a hard outer structure) are released. These statoblasts may float around in currents and disperse or, oftentimes, hitch a ride from waterfowl or other aquatic species. The statoblasts remain dormant until the following spring when warm water causes them to open; at that point, the cycle begins again.
The following video, while admittedly “shocking” is also highly informative. As we gather information and share it with you we hope it will lead us all to make more informed and better decisions. So if you ever see a Bryozoan and wonder what the interior of a bryozoan looks like; that question and more are answered in this short video and we hope it means that we can simply leave Bryozoans in Hotel Lake undisturbed. We think it would be a much more beneficial action if you would report the date and location and perhaps take a photo too.
Bryozoans and their Future in BC
a lot of ???????
In 2017-2018 this species was reported in south-western BC (Stanley Park and the Okanagan). The word “Bryozoan” is very difficult to find in BC newspapers after 2018. Since then, there have been almost no sightings or reports filed. Should we presume they are not here?
A compelling theory has been suggested: that the presence of bryozoans, here in BC, may be as a consequence of climatic change and any associated warming of lake waters. If thats the case will we might see more of them in the near future?
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Many sources advance the obvious, that Bryozoans are relatively understudied, in BC. Anyone can substantiate that because it is hard to locate any government involvement in research or data-collection or the recording of sightings in freshwater lakes.
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If Bryozoans are not being reported elsewhere in BC it does not mean they are not there. They have no direct economic value, and perhaps that is why there is little interest in the species.
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. Their statoblasts are small and hard to identify without the use of a microscope. And, while these large gelatinous
The goal of government should be to document bryozoan biodiversity in BC; by encouraging assistance from various citizen collaborators to initiate fieldwork in freshwater lakes and coastlines of BC.
Because statoblasts have been documented in Hotel Lake, it's reasonable to expect we might soon be able to find and photograph Bryozoans here. Hotel Lake has relatively calm-water conditions and high nutrient levels that are thought to be ideal for Bryozoans. Because they are preyed upon by worms, small crustaceans and small gastropods, they effectively increase the available habitat and diversity in areas that they settle.
And, in areas where Bryozoans are found, we will very likely see very clear water just as we see in proximity to our freshwater mussel beds.
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Perhaps the real mystery is
Because this Bryozoan was first (in recent times) seen in Stanley Park’s Lagoon, we include this short video of that ocassion, published by Vancouver Courier. Enjoy!
References
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Aquatic Phenomena
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​Sponges, Bryozoans & Brachiopods of the Sunshine Coast, BC, Canada
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Science Direct.com
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/bryozoan
Delaware.com
https://wmap.blogs.delaware.gov/2018/12/01/delawares-most-famous-freshwater-bryozoan/
Wikipedia
https://en.wikipedia.org/wiki/Pectinatella_magnifica
2017 CBC story
https://www.cbc.ca/news/canada/british-columbia/oddest-thing-i-ve-ever-seen-jelly-creature-befuddles-kelowna-beachgoers-1.4258378​​​​​​​​​​​​​​
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Stanley Park Ecology:
https://stanleyparkecology.ca/2017/08/29/creature-lost-lagoon/