Director of Security
Grays' Aquatic Services
Lake Mohawk Property Owners Association
"Anyone who can solve the problems of water will be worthy of two Nobel prizes
one for peace and one for science"
John F. Kennedy - 1962
May 31, 2018
Lake Management Strategy and Mission Statement
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 , 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.. 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. E-mail: JeffGray@GraysAquatic.com or Cell: 330.412.4139
(Click for PDF Viewing/Download)
Note: Rapid Temperature Increases / Dissolved Oxygen Declining / Transparency Increasing
Many things are going on in the lake at this time as weather patterns are controlling the overall
biological dynamics within the lake. Water temperatures are increasing, a thermocline is developing,
dissolved oxygen values are declining, water clarity is increasing and last but not least is that the
winter/spring aquatic plant commonly known as Curlyleaf pondweed is increasing!!
Considering that there are many inter-related associations between all these events (aquatic ecology), I
thought I would point out some of the more interesting ones.
1) There was an 11 degree average increase in water temperatures from 5/1 - 5/9 from the surface through
9 feet of depth. There was a 25 degree increase from 5/1 - 5/30.
This relatively rapid increase in water temperature affects most all biological activity within the lake
including the fisheries.
Rapid changes in water temperature can cause thermal stress....especially on spawning fish.
"Why have I seen a partial die off of crappie in the past several weeks?"
Please Visit the Following Links :
Biology/Ecology of Crappie Link
"Why a partial crappie die off may actually be beneficial to the overall ecology of the fisheries & MORE"
2) Rising water temperatures increase the activity of many aquatic organisms in the lake including bacteria in
the lake sediments and water column. Aerobic bacteria consume oxygen as they decompose organic matter.
Also consuming oxygen in the water column are microscopic organisms call zooplankton.
From a chemistry viewpoint, warm water holds less dissolved oxygen than cold water.
(think about a cold soda pop vs. a warm soda pop as a comparison)
The dissolved carbon dioxide (CO2) in a cold soda is much greater than a warm soda.
As an experiment... take two cans of soda and place one in the sun and the other in the refrigerator.
Open both cans over a sink or outside and see which one releases the most CO2 ;-)
3) Why is the water clarity increasing? (10' 2" to 14' 10") Answer - Because the Curlyeaf pondweed (CLP) is increasing.
CLP like all aquatic plants utilize the phosphorus in the water for growth of leaves and stems. The CLP
plants are basically "cleansing" the water of nutrients which otherwise would be free to be used
by microscopic phytoplankton/microscopic algae. The more phytoplankton you have in the water column,
the less clear the water is. Ironically, the less phytoplankton (microscopic plants) you have in
the water column.....the less natural oxygen production you have which is another reason
that dissolved oxygen values are decreasing.
"A potentially nuisance invasive aquatic plant that provides benefits for Lake Mohawk"
a.k.a. "Potamogetan crispus" (scientific name)
As you can see in the illustration below, CLP has a very different growth cycle than most all northern native aquatic plants.
CLP is most visible in spring especially in May when the plant reaches the water surface in depths up to 10 ft.
Seeds (Turions) are produced in May which then fall to the bottom of the lake where the CLP
once again starts to grow in late fall. It grows under the ice until early summer where it
naturally senesces (dies off) and repeats it's life cycle.
Curlyleaf pondweed in Lake Mohawk
1) CLP provides early structure, food, and habitat for the fisheries.
The below screenshots of the sonar images below were taken on May 1, 2018.
The left side of the screen shows the location of the screenshot (black triangle)
while the right side shows the depth and structure of the lake, including fish if any.
As you can see by comparing screenshot 1 and screenshot 2,
Screenshot 2 which shows an area of the lake WITH CLP has many
more fish associated with the plants compared to screenshot 1 that has no CLP.
NOTE: Both screenshots were taken at similar depths (10 ft.) for comparison purposes.
Because Lake Mohawk was man made, it does not have significant areas of
"structure" which would otherwise provide enhanced areas of food and shelter for fish.
Spring growth of CLP provides excellent natural temporary structure for the fisheries during critical spawning periods
which would otherwise be devoid of beneficial fish habitat.
2) CLP helps crowd out other less desirable exotic plants such as
Using natural plant competition to control other less desirable exotic plants is an excellent
ecological and economical approach to nuisance aquatic plant and algae control.
Eurasian watermilfoil is a much less desirable nuisance aquatic plant due to the fact
that it reaches the water surface during prime recreational periods of the lake season (June, July, August)
3) Curlyleaf pondweed naturally senesces (dies off) in June.
The beauty of CLP is that it matures and naturally dies off in June. Regardless of chemical treatment,
CLP will be very scarce by the 2nd or 3rd week in June.
4) CLP Control Strategy
Given all we know about CLP at Lake Mohawk and the wide variety of lake users within the L.M.P.O.A.,
the most sensible approach to managing CLP is selective custom control throughout May into June.
Controlling surface levels of CLP in high use jet ski, boating, and skiing areas is a priority as is
controlling CLP at lakefront properties that utilize their lakefront for early swimming.
Knowing the benefits of CLP on the Lake Mohawk fisheries, areas that are not high
use are left uncontrolled or minimally controlled knowing that CLP
will naturally die off regardless of control measures.
Common sense, understanding, and some compromise on the part of all lake users goes
a long way in peacefully sharing the natural resources that Lake Mohawk has to offer
so that everyone can enjoy
"Believe It or Not Photos"
(Received May 6th, 2018)
also known as "biting off more than you can chew"
Lake Mohawk Walleye
March 5, 2018
7 lbs - 25 inches
The Relationship between Aquatic Plants & Water Clarity
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 is 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 the 2017 lake season, nuisance levels of aquatic plants will be selectively
controlled in specific areas where it most interferes with recreational use of the lake.
Lake Mohawk Depth Map
(Click to Enlarge in PDF Format)
Visitors to this page
Grays' Aquatic Services
Jeff Gray M.S
Applied Aquatic Biologist
Includes Historical Data
(Click on WU Graphic Below)