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Aquatic plant life of BC lakes
My first snorkelling expedition was to a local lake, Cultus Lake which
is close enough to civilization to be quite eutrophic. The water was
very turbid and you could see no further than a foot or so in front of
you as you swam. Aside from algae, I saw only a single macrophyte
(plant), Myriophyllum which grew several feet in length. The warm
eutrophic conditions seemed to suit it. I saw several small fish fry but
could not identify them.
Last long weekend, the labour day weekend, I spent a very interesting
two days snorkelling in Gates Lake here in BC and looking at the aquatic
plants there. There are lots of nice Myriophyllum groves but they do not
grow as tall as those in Cultus lake but formed very attractive small
bunches that would look spectacular if we could grow it that way in the
aquarium. The water was clear and I could see Kokane (freshwater) salmon
at a depth of 15 feet quite clearly. There were several other aquatic
plants which I could not immediately identify. One looked very much like
Cabomba!! Is this possible? It might have been a type of Limnophila
however it lacked the radial symmetry (not stellate, it had irregular
branching) of the leaf petioles at the nodes. Looked for all the world
like Cabomba gone wild!
I also saw Eichornia azurea or a very close relative. Again, this plant
remained small and did not reach to the surface as I would have expected
it to do. Possibly the water was a little too cool for it and it was
another escapee. It must have been growing seasonally because I found it
in more than one spot however and the range of all these plants was so
large that they could not have been put there in a single season.
Another was a yellow green plant with alternate slightly undulate leaves
up to 6" or more in length and about an inch or two in width. On the
flower stalk, within a foot or two of the surface, the leaf shape
changed to a different form, flat, smaller, about an inch in width and
maybe 3" in length. The flowers were submerged and formed a dense bunch
about 1/4" in diameter and maybe 3" in length at the very top of the
flower stalk. These looked like the dominant plant form and grew to be
the largest. The closest plant I can find with this type of leaf
structure is Potamogeton crispus however the coloration is more yellow
and the flowers don't look like those in Baench atlas II. My books
indicate there are several species of Potamogeton but I think they don't
feature the temperate species which cannot adapt to tropical aquarium
temps. I was able to swim in the lake with only minor discomfort. When
it wasn't windy, the shallow parts of the water near the shore were
quite warm and comfortable. The deeper parts were cold enough to make
you shiver. It is a mountain lake in the BC interior but we've had a
warm summer. Its not far from Lillouette lake which is much larger,
deeper, colder and almost impossible to swim in its so cold.
Another small plant with thick, stiff round leaves which grew from a
crown about 3-4" in length. The leaves were perhaps 1/4 or 3/16" in
cross section. It grow only in shallow water and its possible that it
spends part of its life in emergent form. It might have been Limosella
subulata.
The numbers and variety of fish fry which I found swimming in these
aquatic plants was really amazing. No wonder the Kokane would not bite
any artificial baits offered by the fishermen who trolled for hours
without success. I even saw a small suckermouth catfish very similar in
size to Otocinclus but most like a species of Plecostomus. It was
speckled in pattern and matched the coloration of the bottom very well.
Wow!
I wish that I had a jar in which to bring back specimens or that I had
taken a camera. I had no idea that my camping trip would turn out to be
so interesting in terms of aquatic plant life!!
Steve Pushak in Vancouver BC