Aquatic Fish & Invertebrates

This information was provided by the LCPOA Environment Committee, December 2020.
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Quagga and Zebra Mussels

Quagga mussels and Zebra mussels are bivalve molluscs and both are aquatic invasive species (AIS) – meaning they are not native to our lake’s ecosystem. While they are very similar in their breeding patterns, feeding techniques and the development of their larvae, known as veligers, they are somewhat different in their size, markings and shape.
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Quagga mussels grow to be slightly larger than Zebra mussels (about 5cm). Their colouring differs slightly; while they may have alternating light and dark brown stripes their shells can also be solid light or dark brown. Shells are D shaped and cannot sit flat on a surface. Also, when Quagga mussels gain a foothold, they can overwhelm the smaller Zebra mussels.

​​Because Lake Clear has most recently been infested with Zebra mussels, this article will focus on those alone.

Zebra mussels, by comparison are triangular, with a sharply pointed shell hinge, and are able to sit flat on their ventral side.  There is a prominent light and dark brown banding pattern on the shell, which may be smooth or zigzag in shape.

Unlike other molluscs, they have hair-like filaments, called byssal threads, which they use to attach themselves to hard surfaces such as boats, docks, water-intake pipes and even the shells of other mussels.

Zebra Mussels

​​Zebra mussels have separate sexes. Eggs are expelled by females to be fertilized outside of the body by males, usually in the spring or summer. The microscopic larvae in their juvenile stage are called veligers. They emerge within 3-5 days and are free swimming for up to a month, being dispersed by water flow.

After this time, the veligers search for an attachment site, and metamorphosis and secretion of the adult shell begins. The mussels may reach maturity in the first year, but the second year is more usual.

 A fully mature female mussel is capable of producing up to one million eggs per season. Reproduction is prolific and once introduced to a new water body, populations can reach a total biomass at least 10 times that of all other invertebrates. Their densities can reach over 100,000 individuals per square metre.
 
Zebra mussels are filter feeders and each mature adult is capable of filtering at least one litre of water per day, removing plankton and algae; food that other aquatic animals require to survive.

Zebra mussels live for 2 to 5 years and can have a very significant impact on the lake’s ecosystem.

***Please see important information about decontaminating watercraft before launch in lake including new 2022 Ontario Regulation for boaters.***
Watercraft Decontamination

Frequently Asked Questions (FAQ's)

1. When did zebra mussels arrive in Lake Clear?

The Centre for Invasive Species in Peterborough shows that the Ontario Federation of Anglers and Hunters (OFAH) made a report in August 2019, for a discovery near Turner Island. The LCPOA was not notified.
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Of course, we all know of the many recent discoveries around the lake in the summer and fall of 2020.

2. How did they get into our lake?

Since Lake Clear is land-bound with only one outflow through Hurds Creek into the Bonnechere River, the only way for zebra mussels to have entered Lake Clear is through human negligence. The most likely way would be as hitchhikers on a boat that had been in another infested water body and was not cleaned before entering our lake.

3. How many other lakes in Canada are infested?

Zebra mussels first arrived in Canada in 1986. They were found in a harbour in Lake Erie, most likely transported from Europe via transatlantic shipping. Within several years, Zebra mussels spread throughout the Laurentian Great Lakes. By 1991, Zebra mussels began to spread to smaller inland lakes in Ontario and the eastern United States. They are currently found in more than 750 lakes in North America.
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In our immediate area, Mink Lake has reportedly been infested with Zebra mussels for the last 8 to 10 years and both Lake Dore and Golden Lake discovered them more recently.

4. How do they spread?

Zebra mussels are often unknowingly transported by boaters or other water users who don’t realize mussels or veligers have attached to their equipment. 

5. Why are they a concern for Lake Clear’s ecosystem?

The impacts of Zebra mussels have been well documented in lakes across Europe and North America. While the degree to which lake ecosystems are impacted is highly variable, there is certainly cause for concern here.

Zebra mussel populations can reach very high densities. This means infrastructure such as docks, water intakes, boats and other solid surfaces are likely to be heavily impacted.

When found in high densities, the mussels can have strong impacts over algae, which are the base of the food web. In some water bodies, the amount of algae has declined by over 50 per cent, with reverberating impacts to fish and other species that ultimately rely on algae for food.

In some lakes, the fish population has not been largely affected while, in others, there have been dramatic declines. Because Lake Clear is already an ‘at capacity’ lake with concern for the health of the lake trout population, the impacts of Zebra mussels on the dissolved oxygen levels may well exacerbate an already delicate situation. See this link for more information on ‘at capacity’ lakes.
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Zebra mussels have also led to dramatic losses to native mussel populations. The general rule is to expect a 90 per cent loss of native mussel populations within 10 years of their arrival.

6. How do zebra mussels relate to eutrophication?

Eutrophication (from Greek eutrophos, "well-nourished") is when a body of water becomes overly enriched with minerals and nutrients, which induce excessive growth of algae. This process results in dissolved oxygen depletion of the water body after the bacterial degradation of the algae.
 
Zebra mussels, by removing huge amounts of phytoplankton, deplete this food source for other organisms. Accumulation of their decomposing pseudofeces consumes dissolved oxygen and toxic by-products are produced. Changes in water clarity and light penetration alter entire ecosystems by promoting algae growth.

One person recently quipped flippantly “ the good news is, our water will get clearer”. As the water gets clearer and fish begin dying, it may also be a sign that our lake is dying.

In the Laurentian Great Lakes, as well as White Lake near Calabogie, Zebra mussels also caused some new algae problems. Filamentous green and toxic Microcystic blue-green algae that grow attached to rocks in coastal areas began to form extremely large blooms, clogging fishing nets and water intakes, and fouling bathing beaches. This is thought to be a result of the Zebra mussels concentrating phosphorous in the nearshore areas as they eat plants and organisms containing phosphorous and then discard it in a dissolved form, which is easier for the algae to ingest.

 It is too early to say if this will happen to Lake Clear.

7. What other consequences could result from this zebra mussel invasion?

Zebra mussels are likely to have a large impact on infrastructure such as water-intake lines, boats and boat motors, which will now require routine maintenance/de-fouling. Because mussels grow on hard, rocky lake bottoms, and mussel shells can be quite sharp; swimmers will likely need to wear footwear when walking on submerged rocky areas. Users of local beaches may find increases in the accumulation of dead Zebra mussel shells on beaches, which are very sharp and can inflict nasty cuts.
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Because the mussels primarily inhabit rocky areas and infrastructure around the lake edges, impacts will not be evenly distributed around the lake.

8. Can we get rid of zebra mussels?

​Once established in a water body, eradication is nearly impossible.

There are ongoing studies on the topic of eradicating Zebra mussels; however, to date, there are no definitive/practical methods to rid a lake of them.

​There are a number of strategies being applied to lakes, primarily in the United States, to halt and/or eradicate zebra mussels.
See this link for further information
https://invasivemusselcollaborative.net/management-control/control-methods/

9. Is Lake Clear’s ecosystem favourable to zebra mussels?

Unfortunately, YES! Zebra mussels require low salinity levels, dissolved calcium levels (needed to form their shells) greater than 25 mg/L, pH levels somewhat alkaline and slow water flow.

The following table compares Lake Clear measurements to the measurements required to support Zebra mussels and clearly shows that our lake has ideal conditions for Zebra mussels to flourish.

Condition	Lake Clear	Ideal Conditions to Support Zebra Mussels
Low Salinity	Low	Low
Dissolved Calcium	37 mg/L *	>25 mg/L
pH Level	~ 8.4 **	7.5 – 8.5
Flow Rate	3 to 5 years ***	Slow water flow

* This level of dissolved calcium in Lake Clear is surprisingly high for a Precambrian Shield lake.
** pH is a measurement of acidity using a logarithmic scale of 1 to 14. pH 7 is neutral and pH 6 is 10 times more acidic than pH 7, while pH 8 is 10 times more alkaline than pH 7.
*** Lake Clear is land-bound and is part of the Bonnechere River drainage basin. Its flushing rate is 0.18 times/year, which would be considered very slow. Complete turnover takes about 5 years.

10. I have heard that zebra mussels cannot withstand our freezing winters.

Adult Zebra mussels die when aerially exposed to freezing temperatures. In winter, de-watering and exposing Zebra mussels to freezing air temperatures can control populations.
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It is highly unlikely that Lake Clear water levels could be lowered to the levels that would be required to be effective in eliminating them or reducing their numbers.

11. What kind of boat maintenance will be required?

This link is one of many providing advice on caring for your boat.
https://dnr.wi.gov/topic/invasives/fact/pdfs/ProtectYourBoat.pdf

Following is an excerpt:
Proper boat hull, engine maintenance and cleaning are key to saving thousands of dollars in repair costs resulting from damage caused by Zebra mussels. Juvenile and adult Zebra mussels have the ability to attach to many different types of substrate including fiberglass, aluminum, wood, and steel. This ability to attach decreases fuel efficiency and damages the boat’s finish.

Their larvae (called veligers) are extremely small – too small to be seen without a microscope. When veligers are present in the water they can be drawn into engine passages or can move into them on their own. Once they settle out in the engine cooling system, they can grow into adults and may block intake screens, internal passages, hoses, seacocks, and strainers.

The best ways in which boat owners may avoid this type of damage are:

• Use a boatlift to completely remove the watercraft from the water.
• Use your boat periodically - run the motor at least twice a week at slow speeds to kill any Zebra mussels in your engine’s cooling system.
• Lift the motor out of the water between uses if mooring – this reduces the chances of Zebra mussels colonizing the intake grate
• Use ‘motor muffs’ to flush Zebra mussels and other materials from your boat’s motor.

Many of us store our boats at commercial marine establishments, such as PowerTech Marine on Silver Lake Rd. and Pride Marine in Eganville. It would be important to have them perform the necessary maintenance on your watercraft.

12. How can we prevent

The simple answer to this question is to ensure that every watercraft entering or leaving our lake is subject to inspection and decontamination.

​This can only be accomplished by the establishment of a boat wash decontamination station in the vicinity of the lake and will require cooperation from boat owners, resort operators and the minicipality.

At Lake Clear, this approach can be done effectively since we have very few points at which boats can be launched. The majority of boats are launched at Opeongo Mountain Resort on Lake Clear Rd. and a few may be being launched at Weiland Shore Rd.

The implementation of a boat washing decontamination system is planned for Lake Clear. 

13. How can we, as individual property owners, help?

For property owners who store their watercraft on their own property, you need to understand and follow the instructions for decontamination. See your FOCA booklet entitled “A Shoreline Owner’s Guide to INVASIVE SPECIES” or get a copy at https://foca.on.ca/invasive-species-guide/

​Similarly, for visitors to your cottage, ensure that you inspect and decontaminate all their watercraft (canoes, paddle boards, PWC, boats) before allowing them in the water. And, when they are leaving, follow the same process to protect the next body of water they may be going to.

Round Goby
 
In 1990 this European fish was brought into our Great Lakes in the ballast water of ships. It has since spread through southern Ontario lakes most likely by being used as live baitfish.
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The round Goby competes with and may prey on native bottom feeding fish. They also will eat eggs and larvae of native species. Due to their aggressive eating habits and their ability to spawn many times a year they can quickly spread over large areas.
To date, the closest observed and recorded Round Gobies have been in the Rideau River by Smith Falls (150 km to the SE) and in a lake in the Kawarthas (200 km to the SW).

Round Goby

Frequently Asked Questions (FAQ's)

1. How can I recognize a Round Goby?

The Round Goby, with its raised, frog-like eyes, is similar in appearance to the Sculpin, with the most notable difference being a single scallop-shaped pelvic fin. This fin acts as a suction cup making it easy to attach itself to rocks or pebbles. Their full-scaled bodies are brown to grey with dark brown spots and creamy white bellies. There is a characteristic black spot on the rear of the first dorsal fin. Females are 8 to 10 cm in length and males 10 to 13 cm with the maximum being 25 cm. Reproducing males have completely black bodies and fins, sometimes with yellow blotches.

2. How do they impact our environment?

Once established in a body of water, the Gobies spread quickly and displace native fish. Being voracious eaters, they can eat up to 80 zebra mussels a day. Although this may sound like a good thing, mussels often carry botulism and once infected the Gobies change their behavior making them easy prey for fish eating birds, which in turn are infected with botulism. This has resulted in the death of large populations of birds in the Great Lakes Basin.

3. How can we stop the spread?

By learning to recognize this species of fish and reporting any sightings to the Invasive Species hotline we can help stop the spread.

It is also important to empty bait buckets, live wells and bilges before leaving any water body. Clean and wash all boats and fishing equipment before using in Lake Clear. Do not use Round Gobies as bait (it is illegal to have in your possession in Ontario). Dispose of all unused bait and fish waste in the garbage.

More information can be found at:
https://tucanada.org/stop-the-spread-the-round-goby/
http://www.invadingspecies.com/round-goby/