What do fish population assessments tell us?
From fish collection surveys we can determine size structure and growth rates of key fish species. We can make comparisons between your lakes fish growth and that of other lakes and the state average. Depending upon fish capture methods, it may also be possible to determine fish species composition and relative abundance.
At Silver Lake, largemouth bass growth was measured as length-at-age compared to Michigan’s state average. This graph indicates largemouth bass growth is below the Michigan average for ages 1-4. This slow growth may be a result of inadequate prey numbers, high density of aquatic plants inhibiting bass foraging or possibly even poor water quality conditions.
The fish population characteristics, combined with general habitat information can paint a picture of what is happening in your lake. For instance, over abundant and stunted bluegill populations can signal inadequate bass numbers or more likely, a problem with dense aquatic plants inhibiting bass from feeding on the bluegill. Fish assessments can also lead to the discovery of unsatisfactory water quality conditions that may cause poor growth, stress and even death of some fish species.
How are fish captured?
There are several options available for capturing fish. All methods employed are intended to be non-fatal and low-stress for fish. Fish growth assessments require identifying, measuring and collecting scales from captured fish before releasing them. Most commonly we use trap nets and seines to capture fish although hook-and-line and electro fishing are viable options in some cases.
Some lakes prefer to have residents catch fish throughout the summer while collecting the necessary information and scales for the growth analysis. This can be a good alternative, but requires some training to ensure the information gathered is credible and usable in the analysis.
When is the best time to do a fish assessment?
Spring and fall are the best seasons for fish collections, although fish can be collected throughout the year.
Let PLM Lake & Land Management help you maximize your lake’s fishing potential today.
Prior to aquatic management, information must be collected about a lake: its current state and identification of the problem plants. This information is collected through what is called a Lake Vegetation Assessment. These surveys are often required by state governmental agencies in order to permit unique or whole lake treatments.
Lake Vegetation Assessments use a scientific approach to determine the plant communities of the lake. The following information is collected and prepared:
- Vegetation types by depth
- Presence and distribution of aquatic invasive species as well as native plants
- Frequency of occurrence of aquatic plant community
Our experienced staff evaluates the assessments, and prescribes treatments which are both environmentally safe and effective
Studies called bioassays are becoming more readily available for aquatic plants. Plants are taken from the lake and examined to determine how susceptible it will be to the different herbicides. More importantly these bioassays can determine the precise amount of each herbicide required to control the plants. Some plants are more tolerant to the herbicides than others. This allows us to not only be selective by product type, but also by the rate of application. PLM can use the least amount of herbicide to effectively and successfully remove only certain types of vegetation.
PLM offers a wide range of lake management technical services, including lake and vegetation mapping, lake management planning, dredging feasibility studies, and watershed studies and management recommendations. We have and use a wide variety of state-of-the-art lake management and sampling equipment, including dGPS (differential global positioning system) receivers. Before taking action, IT PAYS TO HAVE A PLAN. Carefully planning yields better results and can save you money. We can develop a plan to guide the management of your lake.