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
Updated October 2, 2019
(Note: This will be the last update for the season)
Fall Lake Turnover
Oxy/Temp readings indicate mid stages of "Lake Turnover"
(as of September 26, 2019)
click link above
Fall Lake Turnover
Lake turnover is the process of a lake's water turning over from top (epilimnion) to bottom (hypolimnion) due
to temperature changes throughout the year.
During the summer, the epilimnion, or surface layer, is the warmest.
During the fall, the warm surface water begins to cool. As water cools, it becomes more dense, causing it to sink.
Fall turnover at Lake Mohawk occurs in the northern deeper basin of the lake where the depth reaches up to 35 ft.
Lakes in Ohio are often classified as dimictic lakes meaning that there are two (2) mixes per season. A
rather mild turnover occurs in the Spring while a more pronounced turnover occurs in the Fall.
Imagine standing below the dam at Lake Mohawk looking south (on the golf course) and having the dam be made of glass
instead of earth.
This would give you a cross section of the deeper portion of the lake as illustrated below.
During the summer, the lake becomes stratified into distinct temperature layers. The middle layer
or thermocline at Lake Mohawk generally occurs around 12-14 ft. of depth during mid summer.
Warm water is lighter and less dense and therefore "floats" on the colder more dense layer below.
Due to microbial action and the inability of the deep water to mix with the surface, this
deep water layer becomes anaerobic meaning that there is little or no dissolved oxygen.
Fall turnover provides sort of a "natural cleansing" or renewal process of the lake whereby
deep water can now mix with the surface and become re-oxygenated. This enables then
organic matter that has accumulated on the bottom basin of the lake to become further
degraded by aerobic bacteria (bacteria that require oxygen). The fish population
also now has much more room to thrive and feed before winter ice covers the lake.
Fall turnover can temporarily be very "messy" or aesthetically displeasing but is very
important and essential for the well being of the lakes biota and overall "health".
Current temperature readings indicate that the lake is still in the process of becoming
"isothermal" which means the lake temperatures are becoming
similar from the surface to the bottom.
The closer the temperatures are from top to bottom, the easier the lake
mixes from wind and wave currents.
Deeper lake water (> 12ft.) will now be able to mix with the upper
layers of the lake. This results in a natural
"cleansing" of the lake and restores oxygen to the
deeper depths of the lake.
(Click above for Current Reports)
with 17" Small Mouth Bass
August 1, 2019
*Bald Eagle at Lake Mohawk
Note: I was fortunate and privileged enough see this Eagle on my July 30th visit
Blue-Green Algae & Blooms
It's that time of the year when a little background information on blue-green algae
also known as cyanobacteria is helpful in understanding the changes that are now going on
in Lake Mohawk in terms of water color and general overall appearance. For
those of you who do not visit other lakes in Ohio, blue-green
algae are a common and natural part of aquatic ecosystems especially from the months of
July through September as the graph below illustrates.
The relative amount of blue-green algae present in any lake is dependent on
many factors including the surrounding watershed, weather, Mother Nature, and human influence.
The amount of blue-green algae in a lake directly correlates to the amount of nutrients
within that lake particularly phosphorus and nitrogen.
Nutrients that feed blue-green algae blooms come from either outside the lake from
the watershed carried in through streams and runoff or from within the lake through
lake sediment disturbance and/or deep water chemical release of sedimentary phosphorus during
the summer and fall months.
Lawn and garden fertilizers along with lake sediment disturbance by wind, wave, and water activity
can contribute significant amounts of nutrients to the lake during critical
summer months when blue-green algae populations are already at their peak.
Algae Blooms are "Acts of God and Mother Nature" that are in response
to the environment in which they exist.
As an aquatic biologist managing Lake Mohawk for nuisance aquatic plant and algae
control, I have very limited control over algae blooms especially in a 500 acre lake.
(Click above for July 30, 2019 PDF Graph)
Dissolved oxygen has significantly increased in the upper 12 foot strata of the lake (epilimnion)
The oxygen/temperature profile in the lake is characterized by a warm upper strata of water (epilimnion)
from 12 feet to the surface with a strong thermocline at 15 feet (metalimnion). Dissolved oxygen
has significantly increased since the July 23, 2019 monitoring date where DO readings were between
5.0 and 6.0 mg/l on July 23rd to aboe 8.0 mg/l on July 30th.
As the graph below illustrates, Dissolved oxygen concentrations are preferred for a healthy fisheries
as DO levels below 5.0 can created stressful conditions for fish leading possibly to diseas and even death.
Donna's Fishing Buddy Photos!
Anyone that believes Donna's fishing boat is only for "old people" fishing can now see that this
is not entirely true. Donna recently shared some great photos of her grandchildren having
a great time fishing at Lake Mohawk!!! Family, Fun, Fishing, Skiing, Boating, Tubing, etc..
That is what Lake Mohawk is all about!!!
Cory on the Left & Lauren on the Right
Congrats Cory & Lauren!!
17" Smallmouth Bass
July 12th, 2019
Rare Freshwater Bryozoan Discovered in Bay 3
Most of you may have guessed that the photo below is possibly from someone getting sick from all the
July 4th festivities over the July 4th celebration week. In all actuality as identified by your Lake Directory Rob Greene,
this is a relatively rare freshwater bryozoan. More information on this fascinating organism can be found here:
"Chuck" a lakefront property owner in bay 3 discovered this organism living in the water near his dock.
The email to Rob Greene sort of went like this:
"The other day as we were playing around in the lake, I stepped on a blob of gelatinous material on the bottom of
the lake. It was about 16" diameter and several inches thick. It almost looked like a jelly fish. I didn't know if it
might have been some foam ball or something partially decomposed by the lake ice etc..
I never have seen anything quite like it."
(Dredging Project Temporarily Delayed as Reported in the Lake Mohawk Newsletter)
Bay 3 - Sunday June 30th, 2019
Note turbid (muddy) water from discharge issue coming from sediment pond (not from the dredge itself). Under ideal
conditions, the discharge water is injected with a chemical (polymer/flocculent) which would clarify
the discharge water BEFORE it re-enters the lake. PCI was in the middle of adjusting
the concentration of the polymer which requires very precise dosing before the very small clay
particles will combine and settle in the holding pond before it re-enters the lake.
Bay 3 Settling Pond
Sunday June 30th, 2019
Both Dredges in Bay 3
June 25th, 2019
*Dredge Has Arrived
*2018 vs. 2019 Water Temp/Thermocline Comparison
*Treatment Map Update
The horizontal auger hydraulic dredge pictured below has arrived at Lake Mohawk.
This dredge design is IDEAL for sediment removal at Lake Mohawk for a variety of reasons.
The horizontal cutter/suction head is very efficient for for removal of soft, relatively
shallow sediment depths that are typical throughout much of Lake Mohawk. The wide
suction/cutter head combined with the paddle wheel propulsion system makes
this dredge very efficient with minimal disturbance to the ecosystem and
minimal inconvenience to the property owners by avoiding cables
stretching from shoreline to shoreline which is typical of many dredging operations.
Dredge Arrives June 14th, 2019
Front and Back Views
Horizontal Auger Hydraulic Dredge
2018 vs. 2019
Thermocline - Water Temperature Comparison
The two oxygen temperature tables below outline the significant differences in both
the water temperature and the relative position of the thermocline
between this year and around the same time last season.
In 2018, the thermocline was located at the 12 ft. depth strata while in 2019
the thermocline is 6 feet deeper at 18 feet. The significant differences
in water temperature (nearly 9 degrees) affects not only the position of the
thermocline, but also the general aquatic ecosystem of the lake which affects
both fishing as well as aquatic plant and algae growth in the lake.
Nuisance Aquatic Plant Control Update as of June 12th, 2019
(Scroll Down for Complete Treatment Map)
While conducting my June 12th, 2019 lake assessment, I observed a species of aquatic plant in bays 9/10 (RED)
commonly called Milfoil. Considering this species of milfoil has a high potential to spread quickly
throughout the lake (fragmentation) and the fact that it's tall growth habit can be a nuisance to many recreational activities, I applied treatment to the areas highlighted below in RED.
This is an interesting species of Milfoil and is not your typical "Eurasian Watermilfoil" (Myriophyllum spicatum)
which is often publicized as being a major nuisance throughout many lakes in the U.S.
This species of Milfoil can go through periods of spring fragmentation in which many parts of the plant
will simply break off and spread throughout the lake driven by prevailing winds. This plant is believed to have
been introduced into Lake Mohawk from Beacon Lake.
Is this Giant Fish For Real?!
A LARGE Grass Carp caught in
This fish is 25-30 years Old!
(based on the last estimated stocking date)
(Note: Click Reports and/or Photos)
22" Large Mouth Bass
June 7th, 2019
Lake Condition Update
(as of June 5, 2019)
As can be seen by viewing the June 5, 2019 Oxygen/Temperature data,
the thermocline in the lake is located between the 15ft. and 18ft. depth strata.
Based on average daily temperatures, the thermocline will move upward in the
water column and stabilize somewhere between 12 ft. to 14ft later in the season.
The movement of the thermocline upward will affect dissolved oxygen levels
which in turn affects fish distribution within the lake.
This will change the fishing characteristics of the lake as the fish populations
move to adjust for changing environmental conditions and the associated movement
of their food organisms such as benthic invertebrates, zooplankton, aquatic insects, etc..
The Curlyleaf pondweed (CLP) growth in Lake Mohawk has reached it's maximum growth phase
and is now on the decline in most areas. Chemical control of remaining CLP will be on a select basis
in order to preserve as much natural habitat as possible for the newly hatched fish fry which
is important to the future fisheries of the lake.
As the remaining CLP naturally scenesces (dies off) over the next several weeks,
(or is controlled in select areas where is is creating a nuisance)
we can expect to see the emergence of the summer aquatic species of plants which
consist mainly of Naiad species.
be applied in a manner which is conducive to maximum "natural" control of
Blue Green Algae. Aquatic plants help purify lake water by reducing critical (limiting)
nutrients such as phosphorus thereby minimizing the growth (blooms) of blue-green algae (cyanobacteria).
*American Bald Eagle Fishing at Lake Mohawk
While sampling for the dissolved oxygen/temperature measurements on May 29th, I observed a
beautiful American Bald Eagle circle the northern basin of the lake and then
quickly descend to the surface of the lake where it double clutched
a fish from the near surface of the water. A very majestic sight to see in person!
Surface lake temperatures have risen significantly from just eight (8) days ago where
surface temperatures were 66 degrees to nearly 75 degrees on May 29th.
Interesting to note is also the fact that the lake has developed a much more
distinct thermocline between the 12ft. and 15 ft. depth strata. The thermocline
plays an important role in both the fisheries considering dissolved oxygen often
drops to zero below this level. Another lake phenomenon is that the lake sediments
will now start to release phosphorus into the water column in depths greater than 12ft. This
chemical reaction contributes to summer blue-green algal blooms.
*Updated Treatment Map
Additional areas were treated for select areas of Curlyleaf pondweed on May 29th,2019
The green highlight designates areas that were treated on May 21st, 2019
The yellow highlight designates areas that were treeated on May 29th, 2019
scroll down below
One of Donna Vansickle's Fishing Buddies (Gary Clark)
caught this 17 1/2 inch Largemouth Bass on
May 24th, 2019
Donna and crew fished for 4.5 hours on May 24th and netted 79 total fish.
Curlyleaf pondweed (CLP) Treatment
(a.k.a. commonly known as Mayweed)
Select areas of treatment for CLP were applied on May 21st and May 29th, 2019
as noted on the Google Earth Map below.
Only select areas of CLP will be chemically treated considering this plant is important for both the fisheries
AND the general aquatic ecology of the lake.
As mentioned previously, CLP will experience a NATURAL DIE OFF throughout June
even without treatment. This natural process is called senescence.
CLP Treatment Map (May 21st & May 29th, 2019)
Note - May 21st Treatment for CLP in Green Highlight
May 29th Treatment for CLP in Yellow Highlight
June 12th, 2019
Late Spring/Early Summer Milifoil sp. Appears
June 12th, 2019 Treatment for Milfoil species (Bays 9/10) (RED)
May 15th, 2019 Lake Assessment
While exiting Bay 12 just outside the entrance to the bay, I saw what at first appeared to be a single dead fish floating in the water. In order to determine what may have affected/killed this fish, I
boated closer and netted the fish from the water.
What I discovered was that this otherwise very healthy largemouth bass most definitely
"Bit off More than It Could Chew"
Photo after I removed the Crappie from the mouth of the Bass
Unfortunately, neither fish was unable to be revived.
Another interesting "aquatic critter" that inhabits Lake Mohawk is the
Eastern Spiny Softshell Turtle.
On most sunny days, a group of these turtles can be observed
resting on the banks of what is called the "power peninsula" in Bays 9-10
The photo below was recently submitted by Donna VanSickle
from her May 15th, 2019 fishing trip at Lake Mohawk.
Please click on the link or the picture for more information on this fascinating turtle.
You Know Spring Has Arrived
Donna VanSickle & Crew
are back on the water fishing!!!
Please note that Donna now has her own
which includes photos and her fishing survey reports!!!
Please click the link above or on Donna's Picture below!
Donna VanSickle and Crew
May 15, 2019
Winds at Lake Mohawk during my May 15th, 2019 assessment were W-NW at 8-10 mph . Skies were mostly sunny at 10 a.m. with air temperature at 61 degrees. Water visibility was 5 ft. 7" (no change from May 8th) with the water temperatures ranging from nearly 63 degrees on the surface decreasing to 48 degrees at 33 feet. .
Please click on the below May 15th, 2019 button below for more detail on the oxygen/temperature profile.
Water Temperature/Oxygen Profile
Aquatic plant growth was predominantly "Curlyleaf Pondweed" (CLP) also commonly called "Mayweed" which is a typical lake plant for this time of the season. For a more complete discussion on the importance of this plant and the role
it plays in the aquatic ecology of Lake Mohawk please read more below.
For the most part, the CLP was sparse and reaching near the surface of the water in the several areas although the level
and density of growth has been significantly less compared to previous seasons.
Limited treatment for CLP will most likely begin May 22nd - May 24th due to a number of factors including water temperature, density of growth, recreational areas in which it occurs, and spawning activity of the fisheries.
It is IMPORTANT to remember that nearly all CLP will die off naturally (senescence) WITHOUT chemical treatment by mid-June depending mainly on water temperature.
As mentioned before, Curlyleaf pondweed plays a vital role in the fisheries of Lake Mohawk as well as the natural suppression of undesirable mid to late summer nuisance aquatic plants and planktonic algae. Therefore, for ecological and practical reasons, CLP control will be conducted in a judicious and practical manner over the next 4-5 week period*.
*Treatment Maps will be posted here to keep you informed as to the time, location, and extent of treatment.
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
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)