This topic has mainly been about aquatic weeds and their over-growth, and about the types that become invasive and take over large bodies of water in fresh water lakes and rivers, streams and canals.
I am now going to talk about "Water Fertility" which is important if you, like I, like to fish. You don't have to be a biologist to catch fish, but it helps to know the areas that fish like to be in and why. Also the following information will explain what causes fish to die off or to live happily in ponds or lakes, or river areas.
This term of water fertility refers to the amount of nutrients, such as nitrogen and phosphorus, dissolved in the water. a body of water with high fertility is said to be "eutrophic"; moderate fertility, "mesotrophic", and low fertility, "oligotrophic."
Fertility, in its self, has very little effect on the daily life of fish. If all other habitat requirements are met, they can easily live in water at any of the fertility levels. But fertility does play a role in how many fish a body of water can produce. As in the levels of dissolved nutrients in the water determines how much phytoplankton is produced and this determines how much food is available to the fish.
Fertility has yet another indirect influence on fish, as it is the primary factor in determining the level of dissolved oxygen in the water so it controls where fish can live and where they cannot.
Examples:
Eutrophic lakes, are shallow and weedy, with highly fertile water. Heavy algae blooms develop in the summer months.
Mesotrophic lakes, usually have a moderate depth with good water clarity and water fertility and some weed growth.
Oligotrophic lakes, are generally deep and clear, and infertile with sparse weed growth.
