Director of Security
Grays' Aquatic Services
Lake Mohawk Property Owners Association
Updated August 22, 2016
Fall Turnover at Lake Mohawk has Arrived
Fall turnover in a lake begins when the temperature gradients within
the lake move closer together until the lake water temperatures
between the surface and the bottom of the lake are nearly the same (isothermal).
As warm less dense water (0-12 ft. at Lake Mohawk) begins to cool, thermal
verticle currents begin to disrupt the thermocline which results in
mixing between the upper strata of water (epilimnion) and
the lower strata of water (hypolimnion) from wind and density differences
within the water column.
The complete Fall turnover process can take many weeks to a month or more to
fully complete depending on weather conditions within that season.
Referring to the August 12th and August 18th oxygen/temperature data below,
note how the temperature in the lake from the surface (0 ft.) through 9 ft. has declined
an average of 3 degrees in a one week period. August 12th marks the peak temperatures
in the upper strata of the lake (epilimnion) for the 2016 lake season.
Also Notice how the weak thermocline (a significant temperature gradient between two depths)
that existed between 9ft. and 12 ft. (83.5 / 81.7 respectively) on August 12th has "disappeared"
within one week of the August 18th measurements. (80.8 / 80.8 respectively).
In addition to temperature changes the dissolved oxygen concentrations
at 12 ft. and 15 ft. on August 12 andAugust 18 have changed significantly.
(3.6 increasing to 7.0 at 12 ft. and 0.5 increasing to 2.4 at 15 ft.).
Dissolved oxygen is now increasing in the deeper portions of the lake which will have a direct
impact on fish distribution within the lake. Fish will now be able to thrive in a greater
volume of water. This change in fish distribution will affect fishing in that techniques
used to catch fish in the summer may not be as effective as those needed to catch fish in the Fall.
Other Affects of Fall Turnover
Fall turnover affects a lake in other ways than just temperature and oxygen as mentioned above.
Fall turnover is sometimes referred to as a "natural cleansing" process of the lake
whereby "bottom water" (hypolimnion) that is low in oxygen and high in nutrients and other
byproducts of bacterial decomposition such as hydrogen sulfide are mixed in the upper
strata where oxygen "detoxifies" the water. Having the "bottom water" detoxified is
critical to supporting fish and other aquatic organisms through Winter ice on conditions.
One of the biological affects of turnover is the mixing of phosphorus into the upper water layer (epilimnion) of the lake which contributes to August/September blue-green algal blooms. Fortunately however, there is a relatively complex but important reaction that occurs between phosphorus and dissolved iron in the presence of oxygen in a lake that helps bind phosphorus thereby making it biologically unavailable to algae over time. (Ferric Phosphate Reaction).
(NOTE: Fall pollen at Lake Mohawk is also believed to be a significant source of phosphorus)
As the graph below indicates, August/September is a natural peak period for blue-green algal
populations in most all lakes.
Bay 3 Virtual Shoreline Tour
August 18th, 2016
(Click link above or photo below for more areas around the lake)
Note: Most recent treatment for nuisance aquatic plants/algae applied on
August 18, 2016
Blue-Green Algae suppression treatments and additional Naiad
treatments planned for the week ending August 27, 2016 on an as needed basis
Bay 9 - Barefoot Bay
Lake Mohawk 2016
"Behind the Scenes Look of What You May Not Know"
(August 2016 Blog)
Lake Mohawk as I have mentioned many times remains one of the
most pristine lakes in Ohio in terms of water quality as measured by
water transparency, aquatic plant species, fish populations, and a whole host
of other biological indicators. Despite the fact that Lake Mohawk is a very high quality lake, there are threats that do exist that can adversely affect both the lake and human safety.
One of the most significant threats to all lakes including Lake Mohawk is the potential for toxic blue-green algal blooms. A secondary long term threat to the ecology of Lake Mohawk is the algaecide (copper sulfate) that is used to control blue-green algae blooms. Continued use of copper sulfate can lead to "copper bottom" lakes that do not support plant life in addition to being toxic to food organisms that supports a healthy fisheries. The eventual result of a "copper bottom" lake is having a lake that can only supports algal blooms with little or no plant growth. Light penetration into the water can become so limited that aquatic plants will no longer grow resulting in algal blooms and a stunted undesirable fisheries.
An example of a "sister lake" to Lake Mohawk
(both lake communities were constructed by the same developers) that CANNOT support aquatic plants is Lake Choctaw located in London, Ohio.
Water clarity in this lake is most often between 12-18 INCHES.
Starting in 2009, it was decided by a dedicated group of people on the Lake Committee and
Board of Directors to prioritize lake management objectives which included a variety of
"lake restoration" and "protection" measures. At that time, it was decided that the
control of potentially toxic blue-green algae that could "close the lake" to water contact
activities was a "top priority". An associated priority was to reduce the use of copper
sulfate that would eventually destroy the overall ecology of the lake which in turn would
adversely affect property values. Although non-copper based algaecides do exist
(Green Clean for example), they were found to be too cost prohibitive for a 500+ acre lake.
The most feasible natural low cost alternative for reducing algal blooms is to
utilize natural aquatic plant populations in the lake. Aquatic plants compete for phosphorus,
stabilize phosphorus containing sediments, and may secrete inhibitory chemicals against
phytoplanktonic algae responsible for algal blooms. While this method is very effective, it
is not without it's drawbacks especially in a lake with many shallow bays with high
levels of recreational activities from propeller driven watercraft. The negative
affects are of course plant cuttings from plants that have a taller growth structure.
Selective chemical methods and herbicides have been effective at changing the
aquatic plant community from that of exotic non desirable aquatic plants (Milfoil for example)
to native species such as Slender Naiad. Slender Naiad unfortunately has a flowering stage
in July that grows in the shallow bays and is easily cut from boat traffic if left untreated.
The dilemma here therefore is to either leave the flowing Naiad untreated, which then often ends up as a mass of cuttings in front of a lakefront property owners or to treat the plant which
significantly contributes to the chances of a blue-green algae bloom.....especially in a
hot, dry, sunny summer season like we are experiencing in 2016.
THE IDEAL SOLUTION to the above situation IF MONEY were NOT a factor
would be to mechanically harvest
(NOTE: it would require several harvesters and a transport barge)
the tops of the Slender Naiad
deepen the bays through dredging
in which the depth would either be limiting to the plant or the plant would grow deep enough that it would not be cut off by boat propellers. FYI, dredging the bays is currently under
intense and diligent study by the Lake Committee with significant progress being made. Until
more permanent solutions are implemented such as dredging, please know that herbicidal control of slender naiad has been extensively applied in the last several weeks that will significantly reduce cuttings while attempting to maintain the deeper growth
that does not interfere with recreation but still helps in reducing blue-green algae blooms.
Most people will never realize the dedication and time that the Board of Directors,
the Lake Committee, Lake Manager, and many other volunteers put in to insure the overall safety, satisfaction, and enjoyment of all members of the L.M.P.O.A. throughout the year. Personally, I am most impressed on how thorough and frugal these individuals are
at managing and examining alternatives to accomplishing potentially very expensive projects.
Furthermore, all of these individuals bring a wide variety of professional backgrounds and
experiences that benefit the entire L.M.P.O.A. community. Please know that It is a pleasure to serve a community that supports sensible lake management goals that will affect both current and future generations. On behalf of myself and others, your understanding and support is
If you have any questions, please do not hesitate to contact me at your convenience.
The Relationship between Aquatic Plants & Water Clarity
As we enter the months of July and August at Lake Mohawk, I believe it is important to have a basic
understanding of the important role of submersed aquatic plants as it relates to water clarity.
While many of us may know about the importance of aquatic plants to fish populations, it is
lesser known about how aquatic plants help maintain water clarity and purity.
Besides providing food and habitat for fish, aquatic plants stabilize lake sediments that are
high in phosphorus. Phosphorus that is mixed up from wind, wave, and other recreational
watercraft traffic "feed" undesirable algal blooms that reduce water clarity. In addition,
aquatic plants utilize and compete for available phosphorus making it less available to
the tiny planktonic algae. There is also some evidence that aquatic plants
secrete inhibitory chemicals that reduce algal blooms.
Our lake management goal at Lake Mohawk has been to balance the needs and wants of a
variety of recreational users and property owners throughout the season without jeopardizing
the long term health of the lake. Using aquatic plants as much as possible to
reduce the intensity of algal blooms, reduces the need for ecologically undesirable algaecides.
Throughout this next two months, nuisance levels of aquatic plants will be selectively
controlled in specific areas where it most interferes with recreational use of the lake. All
attempts will be made to assure that boat and jet ski access to and from the main body
of the lake is clear of nuisance growth. Areas with swim platforms will also be targeted for
selective control. In areas where it is believed that aquatic plants to do not significantly
interfere with recreation, aquatic plants will be left to grow to help in the natural
suppression of undesirable algal blooms....not to mention the benefits to the fisheries.
Meet the 2016 Lake Mohawk Summer Intern
Meet Tom Roseberry of Lake Mohawk holding up is prized giant Redear Sunfish
caught at the dock of his lakefront home.
Tom is doing a summer internship with me this season by monitoring dissolved oxygen,
temperature, and secchi disc water transparency readings.
Tom Roseberry is a recent graduate of Hoover High School and will be
entering the Biology program at Wittenburg in August. This young man plans on
going into marine biology and is especially interested in the fisheries of Lake Mohawk. Tom is also
a skilled soccer player and will be playing for Wittenburg this season.
Tom is a pleasure to work with and does a great job in collecting and learning about the
aquatic ecology at Lake Mohawk.
Fishing Photo Submissions
Jim Morgan, Art Leasure, Mike McCoy
It would not be a summer without fish photo submissions from the
avid Lake Mohawk fishermen of Jim Morgan, Tom Leasure, and Mike McCoy!!!!
Great looking fish guys!!! Glad to see you're having fun!!!
Water Clarity & "Mother Nature"
I received an e-mail the other day from Donna VanSickle who is without out a doubt
one of the most.... if not the most..... avid fisher"woman" at Lake Mohawk.
Donna and her "fishing buds" as she calls them can often be seen in their pontoon boat fishing the entire shoreline and open waters of Lake Mohawk.
Donna's keen awareness of the lake provides me with valuable
feedback about the "health" of the lake through her observations on fish counts and
changes is lake water conditions.
Donna recently sent me a complimentary thought provoking e-mail that I would like to share as
it had some important points to be aware of as we quickly approach the summer months
of July and August.
While I truly appreciate her comments such as
"The water looks great" and "Thanks for all you do!"
I would like all L.M.P.O.A. members to know that it is not so much what I do.....
it is more what "Mother Nature" does. The only thing that I do is to
try and work with "Mother Nature" to the extent that I can, to make Lake Mohawk a safe
and enjoyable recreational lake for many years to come.
June 14, 2016 at 5:54:20 PM EDT
"The water looks great! So clear and clean."
As Donna has observed, Lake Mohawk is one of the most pristine lakes in Ohio
as measured by average secchi disc depth (2011 C.L.A.M.)
Even though Lake Mohawk is one of the clearest lakes in Ohio on average,
it is still subject to the ecological changes of "Mother Nature".
One of those seasonal changes is known as "Algal Succession" (figure 19)
Please know that water clarity in Lake Mohawk will continue to decrease as we head into
July and August. This decrease is perfectly normal for most all Ohio lakes.
The decrease in water clarity is due to a variety of reasons
including an increase in not only phytoplankton, but also from the microscopic "animals"
(zooplankton) that feed on these plants along with pollen, sediment suspension
from wind and boat traffic, etc..
The important thing to remember is that phytoplankton play important roles in the overall "health" (ecology) of Lake Mohawk in a variety of ways including being a part of the fisheries food chain, oxygen production, natural shading/suppression of nuisance aquatic plants, etc..
Website has moved to a new location!!!
Fish Structure Drop
The Lake Mohawk Lake Restoration and Protection Committee
has continued to enhance the Lake Mohawk fisheries by
placing fish structures in select locations around the lake.
Below is a photo that shows the locations of the 2015/2016
fish structures and the material they are comprised of.
Note: These structures have been placed and secured at depths of 12-15 feet
and do not pose any hazards to surface water recreation.
Northern Pike caught from shore April 2016
Congratulations to our unidentified angler!!!!
New for 2016
On March 1, 2016, a weather station & beach webcam were installed near the
clubhouse to continuously monitor and record weather conditions at
The Lake Mohawk weather station monitors and records precipitation, wind direction,
wind velocity, barometric pressure, relative humidity, and solar radiation. This station
is part of the WeatherUnderground / Weather Channel network that
monitors and reports weather across all of the U.S. and beyond. The station is connected via
WiFi which also enables the addition of a "Beach Weather Conditions Webcam" .
For detailed weather information of the Lake Mohawk/Malvern area, please click on
or the "Weather Underground" widget to the right
Update: "Mayweed" (Curlyleaf pondweed) has been controlled for the 2016 season
Click for more Information
By working with "Mother Nature", you can enhance the recreational value of freshwater aquatic ecosystems such as Lake Mohawk. Selective and judicial use of aquatic herbicides which promotes natural competition from native low growing aquatic plants is part of an integrated approach to improving property values, sport fisheries, as well as recreational usage from skiers, pleasure boaters, etc.. Studying and controlling the sources of phosphorus will also naturally reduce or eliminate the threat of toxic blue-green (cyanobacteria) algae blooms. The Lake Management Committee at Lake Mohawk (click), consisting of dedicated members of the L.M.P.O.A. from a variety of backgrounds is vital to the success of any lake management program. Your support for this group of people is truly appreciated.
My mission at Lake Mohawk is to serve, share knowledge, and answer all questions about the aquatic ecosystem that is the focal point of this beautiful lake community. It is my desire to further enhance the existing fisheries while minimizing any negative impacts this may have on recreational boating, etc.. Monitoring the "health" of the lake and posting my results on this web site is also a priority. Above all, I am here to serve the greater good of the Lake Mohawk Property Owners Association and will at anytime be available to answer questions or to respond to concerns or observations regarding lake conditions.
Human health and property values of ALL L.M.P.O.A. members are affected by the water quality of Lake Mohawk. In order to understand the various factors that have the most impact on the lake, I have constructed a diagram of interactions that exist between property owners, lake users, aquatic plants, blue-green algae, phosphorus, and copper.
Blue-green algae (photo below - microscopic "plant like" bacteria) blooms are potentially harmful to humans and wildlife due to the production of toxins under certain conditions. The severity of health impact depends on the type of toxin as well as the route of entry (ingested) or location of contact (skin/eyes). Blue-green algae may also negatively impact the ecology of the lake (i.e. fishing) by reaching a point where it shades out light to bottom growing beneficial plants. For this reason, controlling blue-green algae in a manner that does not jeopardize the long term "health" of the lake (which directly affects property values) is the primary lake management objective at Lake Mohawk.
at Lake Mohawk
commonly known as
Curlyleaf pondweed or Mayweed
Potamogeton crispus - scientific name
Description - Curlyleaf pondweed (CLP) is an interesting aquatic plant that begins it's life cycle during the Winter. This plant begins growing under the ice from "seeds" called "turions". From "ice off" (March) through the month of May, this plant can be seen growing in water depths from 3 feet to 10 feet throughout the lake. This plant reaches it's peak density and height in May and early June where it then begins to "die off naturally" (senescence or end of life cycle). By mid-to late June, most all of the CLP will have naturally ended it's life cycle.
Ecological Importance of CLP to Lake Mohawk - Although CLP is actually an invasive/exotic species of aquatic plant (normally undesirable), this plant plays an important role to the aquatic ecology of Lake Mohawk. More specifically, this plant is an important early "structure" in the lake which provides protection to young fish and acts as a "food substrate". Many small aquatic food organisms live on and amongst the leaves of the CLP plant.
The graph below (left screen) is a screenshot which illustrates the close association of fish and CLP within Lake Mohawk.
The "plumes" rising from 10 ft. of water depth up to about 4 ft. of water depth are
CLP plants. The small fish pictures and associated water depths near the CLP illustrates the
close relationship of the plants and fish. Lake Mohawk has very little in the way of
natural permanent structure which is important to a healthy fisheries.
Management / Control of CLP at Lake Mohawk - Fisheries and Recreational Considerations
Fisheries Considerations -As mentioned above, CLP naturally ends it's lifecycle in mid-June. Spring spawning periods begin when water temperatures have reached 55-65 degrees for largemouth bass and bluegill normally spawn in June with multiple spawns possible through August.
Recreational Considerations - Boating, Skiing, Swimming, Jet Ski's, Etc. - Although CLP naturally dies off in mid-June, it is necessary to improve select areas of the lake with chemical control to avoid propeller entanglement, etc. considering that lake use increases significantly beginning with Memorial Day.
CLP Management / Control Objectives and Ramifications - The chemical control of CLP is relatively easy and quick. CLP is not resistant to chemical control provided the correct concentration and appropriate chemical(s) are utilized. The three main considerations therefore for chemically controlling CLP involve: 1) Fisheries, 2) Recreational Considerations, & 3) Economics.
The primary areas that are targeted for chemical control of CLP are "DENSE" areas of growth that are at or very near the surface in recreational boating and skiing areas. Areas of CLP within the 80 ft. from shoreline zone (as marked by the floating buoys) are generally not treated UNLESS they are causing access issues for the lakefront property owner OR they are at the surface. CLP plants that are at the surface within the 80 ft. zone are "top treated" to reduce the seed (turion) production of the plant. "Top Treating" the CLP plant preserves the bottom portion of the plant for spawning fish, etc..
CLP plants that are sparsely growing in deeper water (8-10 feet) are not treated for a variety of reasons which includes economics and a low probability of becoming a nuisance. Remember, ALL of the CLP will die off naturally in mid-June whether treated or not.
Please remember that the control of CLP has a degree of subjectivity. The Lake Mohawk, Lake Restoration and Protection Committee is always active in monitoring the balance of the lake to serve all Lake Mohawk Property Owners. Aquatic plants and algae change throughout the season just like land plants do. Providing a healthy balance of nuisance free lake conditions involves a rather complex balance between man and environment. Human health, property values, and your seasonal enjoyment of the lake remain a top priority of the Lake Mohawk Board of Directors, the Lake Mohawk, Lake Restoration and Protection Committee and myself. Please feel free to contact me with any specific questions or concerns. JeffGray@GraysAquatic.com
Grays' Aquatic Services
Jeff Gray M.S
Applied Aquatic Biologist
NEW for 2016
Includes Historical Data
(Click on WU Graphic Below)