There are four major types of aquatic vegetation; floating, submerged, emergent and algae. As you can imagine the submerged and emergent vegetation are relatively easy to distinguish. However, those types of vegetation that fall into the algae and floating plants categories can be a little harder to tell apart. In this blog post, we'll help you learn how to identify the aquatic vegetation in your pond and understand why controlling it is such an important part of pond and lake management.
Floating aquatic vegetation refers to a plant that floats on the surface of the water and has its roots suspended directly in the water column. The roots of these plants are not buried in the pond substrate. Instead, these plants actually pull nutrients directly from the water to perform it's necessary functions for survival. Giant Duckweed, Giant Salvinia, Water Hyacinth, and Mosquito Fern (pictured left) are just a few of these types of plants that are commonly found in Texas. Being able to float on the surface allows these plants to drift all over your pond. This type of behavior allows the population to spread and have a wide distribution in multiple areas of your water body. In some cases, these plants can potentially cover the entire surface of coves or small bodies of water. Once this occurs, all transfer of oxygen from the surface of the water is shut off, and that area becomes a dead zone to fish and other forms of aquatic life.
As you can probably guess, submerged vegetation is anything that keeps the bulk of its mass submerged and grows below the surface of the water. There are some slight caveats to this, however. Some forms of algae can appear to be submerged aquatic plants, but we will focus on that in the algae portion. These plants are rooted in the substrate of the pond floor and can reach the surface of the water. These plants can have leaves that float on the surface of the water, or the vegetation can form extensive mats on the surface. Submerged vegetation is one of the more broad categories and has multiple species that resemble one another. These plants provide excellent habitat for your fry and juvenile fish to evade predation after they have hatched. Many aquatic macroinvertebrates also feed on these plants, which provides a food source for your fishery as well. Types of this vegetation that are often observed include; Baby Pondweed, Coontail, American Pondweed (pictured left), and Bushy Pondweed. Like I said, this type of vegetation can provide high-quality fisheries habitat as well as a food source for migrating waterfowl. It can, however, be a nuisance if allowed to reach vast expanses of your pond. This type of vegetation can limit fishing success by providing too much habitat for your baitfish, making your predators search larger areas and work harder for their meals. It can also lead to oxygen depletion. Plants produce oxygen during the day, but at night they start to consume oxygen in cellular respiration. If there is a large enough quantity of submerged vegetation, this can drive the oxygen levels down to the point that there is the potential for a fish kill.
Emergent aquatic vegetation can include plants that are in marginal areas where the pond and land meet, or out in open water. These plants are characterized by being rooted in a substrate, whether it is the pond floor or the bank, and have the majority of their plant mass out of the water. With the majority of their mass being above the surface of the water, their structures are more rigid and sturdy when compared to other types of aquatic vegetation. These are probably the most recognizable types of aquatic vegetation, for obvious reasons.
Species that are common in Texas include; Rushes and Sedges (pictured above), Lilly's, Willow, Cattails (pictured left), and Water Primrose. Some of these species show up in shallow areas far from the bank, and others start near the shoreline then work their way out into the water. Those plants that start at the bank and extend out are providing an excellent management aspect to your pond. They help to keep the bank from eroding away from strong winds and wave action as well as slowing down the water that is coming into your pond from torrential rain events. By slowing the water down, these plants allow the sediments to fall out before they reach the main body of water, helping to prevent your pond from becoming turbid. While this type of vegetation doesn't directly affect your fishery in the same way as the others, it can take over the entire bank, making access to your favorite fishing hole nearly impossible.
Algae are some of the most basic, oldest, and confusing types of aquatic vegetation. They have no real root system, and yet some species connect to the pond floor in a very similar way to plants, which makes them easy to confuse with submerged vegetation. Algae can form extensive mats that appear to be a floating plant and drift across the surface of your pond, showing up in a different area today as compared to yesterday. True rooted plants may even begin to grow in these mats if they are left un-managed for long enough.Algae can also be tiny particles that are suspended within the water column, helping to provide resources for the entire food web dynamic of your fishery. Some species like Blue-Green Algae and Golden Algae can emit toxins that are harmful to fish and wildlife, as I'm sure you heard about this past summer.
The most pervasive and easily recognized type of aquatic vegetation is an algae. The algae to which I'm referring occurs in the stock tanks in the deserts of West Texas just as frequently as it shows up in the ponds of East Texas. The species is Filamentous Algae. It readily grows from the pond floor in long chains resembling strands or filaments, giving it its name. Like submerged and floating aquatic vegetation, this algae provides cover and a source of food for your fry and juvenile fish but can lead to oxygen depletions if allowed to reach high enough densities.
Pros and Cons of Aquatic Vegetation
Many pond owners consider aquatic vegetation to be a nuisance, no matter the density, which is the wrong way to view this from a fisheries standpoint. This type of habitat is critical to the viability of your pond being sustainable and providing a source of tightly woven, complex habitat for your juvenile fish to evade predation. It also is a food source providing resources to benefit the growth of that trophy bass from the base of the food chain up. That being said, if allowed to reach large densities, aquatic vegetation can limit fishing success, fishable habitat, or potentially decimate your entire fishery. Managed portions of all four types of habitat can provide crucial aspects when viewing the success of your pond as a whole. Of course, artificial habitat can play a major role in providing much-needed habitat and maximize fishing success.
The main questions to keep in mind when trying to determine the types of aquatic vegetation you have are;
- Where is the majority of the vegetation located?
- Is it truly rooted in the pond substrate?
- Or are the roots free-floating, and it is just growing to reach the surface of the water?
Once you've answered these questions, you can determine how much and what type of growth is appropriate to your situation and take steps to control the vegetation. If you run into any confusion, you can always email us photos, and we'll help you out.