A new invasive species in Ontario waters....Fresh Jellyfish

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It isn't native to Ontario and other than hitch hikers on trains or trucks until just over 50 years ago there was no reproducing population.

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Range
The Virginia opossum is found throughout Central America and North America east of the Rockies from Costa Rica to southern Ontario, it seems to be still expanding its range northward and has been found farther north than Toronto. In recent years their range has expanded west and north all the way into northern Minnesota. Originally native to the eastern United States, it was intentionally introduced into the West during the Great Depression, probably as a source of food, and now occupies much of the Pacific coast.

I saw thousands of them 10 years ago in Marten River Provincial Park. They arent "new" by any means to Ontario.

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Originally Posted by mastercaster

I think they are in all waterbodies, and people are just hearing about them more with the advent of the internet. I believe they have always been here, and are not invasive.

MC

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Let's try this again simplified....

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Originally Posted by mosquito

Brinsmead explained freshwater jellyfish are native to the Yangtze River basin in China. .... “likely introduced as a hitchhiker with imported aquatic plants”

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https://nas.er.usgs.gov/queries/Fact...SpeciesID=1068
Craspedacusta sowerbyi - Native Range: Craspedacusta sowerbyi is indigenous to the Yangtze River valley in China

http://eol.org/pages/203281/details
Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Craspedacusta sowerbyi is indigenous to the Yangtze River valley in China where it can be found in both the upper and lower river valley. As early as 1880, it was introduced to Regents Park in London, as an associate of aquatic plants impunded there and has since spread throughout Europe, Asia, and North and South America and is widely reported from rivers and lakes in almost every U.S. state between 33 and 43 degrees north latitude



The jellyfish can be spread in the same way zebra mussels have through eggs or juvenile ones on aquarium plants, birds etc. and they are obviously spreading. With man's influence and their being almost invisible most of their lives we can expect to see them spread even more. Taking the time line of 1800's, about the time the carp arrived, since the common carp got here by way of Europe they may have arrived in the same tank of water, but one is almost invisible and the other destroys fish nests and wetlands.

Sightings
http://freshwaterjellyfish.org/canada-sightings/

Yep, they have been around for awhile...

• Bull Lake (1955*) [*cited in McAlpine, et. al.]
• Christy Lake, near Perth, (1966)
• French River, Sudbury (*1980) [*cited in McAlpine, et. al.]
• Georgian Bay, near Parry Sound, Hwy 69 (1952*, 1980, 1998) [*cited in McAlpine, et. al.]
• Hidden Bay, Parry Sound (1957*)

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Originally Posted by jaycee

Range
The Virginia opossum is found throughout Central America and North America east of the Rockies from Costa Rica to southern Ontario, it seems to be still expanding its range northward and has been found farther north than Toronto. In recent years their range has expanded west and north all the way into northern Minnesota. Originally native to the eastern United States, it was intentionally introduced into the West during the Great Depression, probably as a source of food, and now occupies much of the Pacific coast.

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They introduced them ..... boar, common carp and Opossum ..... 3 terrible species to introduce in my book, all given the chance they will spread invasivly and all are destructive to the original residents of the new territory.... 1 atleast makes a good BBQ and the other two are suitable for fertilizer given the chance and let's add the accidental intro the Starling and we can grow some nice roses and butterfly bushes and a better more natural environment.


Jellyfish however we don't know the effect YET and by their nature once in an environment unremoveable.

Hey, we also introduced Brown trout, Rainbow trout, Chinook Salmon, Coho Salmon, Pink Salmon, European hare, Ring Necked Pheasant, Chukar Partridge etc, etc

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I don't understand why they're announcing this as "new". These "Crasps" have been common for over 60 years in Ontario waters. The best clouds of them I've seen are on Kashagawigamog lake in the Haliburton highlands. Nothing new here.


Great Lakes Region: Craspedacusta sowerbyi was discovered in the Huron River near Ann Arbor, MI, in 1933, and in Lake Erie shortly thereafter (Mills et al., 1993). It has since been recorded in Lake Huron and Lake St. Clair, as well as dozens of inland lakes and streams throughout the region, in the states of IL, IN, MI, MN, NY, OH, PA, and WI. In Canada, freshwater jellyfish have been known in Quebec since 1955 and in Ontario since 1980 (Peard, 2002).

Ecology: Craspedacusta sowerbyi occupies a range of freshwater habitats. In its native range, it typically inhabits shallow pools along the Yangtze River, sometimes coexisting with a related species, C. sinensis, which occurs in the upper river valley (Slobodkin and Bossert, 1991). In this environment, changing conditions in the main river system expose jellyfish to fluctuating water levels, temperatures and plankton populations. Where it is introduced, C. sowerbyi is most commonly found in shallow, slow moving or stagnant artificial water bodies such as ornamental ponds, reservoirs, gravel pits, and quarries (Pennak, 1956; DeVries, 1992; Peard, 2002). It has also been reported in large river systems, including the Allegheny, Ohio and Tennessee River systems, natural lakes, aquaria, and ornamental ponds (Beckett and Turanchik, 1980; DeVries, 1992; Peard, 2002).

Craspedacusta sowerbyi is able to reproduce both sexually and asexually. Mature hydromedusae reproduce sexually by broadcasting gametes into the water. Fertilized eggs grow into ciliated planulae (larvae), which then settle and metamorphose into the polyp form. Polyps are capable of budding to produce hydromedusae, as well as either daughter polyps that remain attached to the parent, forming a colony, or frustule larvae which move to new locations before metamorphosing into new polyps (Pennak, 1989; Slobodkin and Bossert, 1991; Peard, 2002).

Hydromedusae are produced only sporadically, and a given location may go several years between blooms (Peard, 2002). Blooms are thought to be temperature dependent, requiring water of at least 25° C, and are most common in summer and fall (Kato and Hirabayashi, 1991; Dodson and Cooper, 1983; Anonymous, 1997; McGaffin, 1997; Peard, 2002). Other factors that may affect hydromedusa blooms include zooplankton populations, alkalinity, and calcium carbonate (Acker and Muscat, 1976; Koryak and Clancy, 1981; McCullough et al., 1981; Angradi, 1998). The more cold tolerant polyp form may have a wider distribution than the hydromedusa form, but because it is inconspicuous and easily overlooked, its range is difficult to determine (Kato and Hirabayashi, 1991; Angradi, 1998). Polyps overwinter by contracting into resting bodies called podocysts, which are essentially dormant cellular balls surrounded by a protective chitin-like membrane that allows them to withstand more extreme conditions than the active forms (Peard, 2002). When conditions are favorable, the podocysts grow into polyps again.

Like other cnidarians, C. sowerbyi is an opportunistic predator, feeding on small organisms that come within its reach. Both polyp and hydromedusa forms use nematocysts (stingers) to capture prey. Polyps are able to camouflage themselves by secreting a sticky mucous that adheres particles to their body (Pennak, 1989; Peard, 2002

The media sure likes to recycle stories when they can't come up with something on their own .....


Freshwater jellyfish invade Lake Erie and experts say there's no way to stop them
'There's no known way to remove freshwater jellyfish from a lake ecosystem once it is there,' said Jeff Brinsmead, senior invasive species biologist
http://nationalpost.com/news/canada/...1-4672561045d6

Smallmouth bass in brook trout lakes.
Zebra mussel bad for some fish.
Coyote high dencity.
People using up natural world.