Posted by Chester Morton / Thursday 11 May 2023 / No comments
What are the characteristics of invasive alien species like water hyacinth, water lettuce, papyrus reed and hornwort in fishery habitats
WHAT ARE THE CHARACTERISTICS OF INVASIVE ALIEN SPECIES LIKE WATER HYACINTH, WATER LETTUCE, PAPYRUS REED HORNWORT, ETC., IN FISHERY HABITATS
Introduction
Invasive alien species have become a major problem in many parts
of the world. These non-native species often spread quickly and cause
significant ecological, economic, and social damage. In this article, we will
identify and describe some alien invasive species such as water hyacinth,
Papyrus reed, water lettuce, and more. We will explore their morphology, mode
of propagation, growth and development.
IDENTIFICATION AND DESCRIPTION
Water hyacinth (Eichorniacrassipes)
Water
hyacinth is one of the common alien invasive species in the world. The leaves
of the plant are bright green and the flower is purple in colour. Its leaf is fan-shaped. It also has thick and
spongy stalks and the roots are thick and fibrous. The leaves are oval to
heart-shaped and can reach up to 20 cm in length.
The
water hyacinth plant is able to quickly adapt to its environment. It can also
by a variety of methods. One common way by which it spread is by the use of
water currents. It can also be spread by the wind. Humans also constitute a
major mode of spread when they when they transport the plant from one location
to another. Typically, the seeds of the water hyacinth plant can thrive for
many years so it can reproduce rapidly through the seeds.
One
important characteristic about the water hyacinth is that, it can grow and
develop rapidly. Within a space of weeks, the plant can form dense mats to
cover an entire water body. When this happens, the amount of light available
for other species is reduced. This subsequently reduces the amount of oxygen
available for other species. This can lead to a decrease in biodiversity and a
decrease in the number of fish in the area.
Another important alien invasive species is called Papyrus reed.
This water plant is very tall, sometimes up to 15 feet. It has a triangular
shaped stem and ribbon-like leaves. The leaves are long and narrow. The mode of
propagation for this plant is through rhyzomes. The rhyzomes are underground
and can produce new shoots. This plant thrives in wet soil and shallow water. It
takes just 90 days for the plant to mature. This invasive alien species is a
huge problem for the fishing industry. This is because the reeds can clog up
fishing rods, reels, and nets. The plant can inhibit the movement of fish. Is
also serves as a barrier to the level of oxygen in the water. The low levels of
oxygen can affect the health of the fish.
Kariba weed (Salviniamolesta)
Another
type of alien invasive species is called Salviniamolesta. It is commonly called
Kariba weed. The plant is native to South America and can propagate and spread very
quickly when first introduced to new bodies of water. The Kariba weed has a
bright green colour and floats freely on the water body forming a dense mat across
the surface of the water. It can grow up to a height of 20cm. The Kariba weed
is easily spread by the wind, birds, and other animals. The weed spreads
quickly to new water bodies and once it is established at a new place, it
overpowers other plants in the area and distorts the biodiversity of the area. Since
Kariba weed can easily and quickly grow and spread over the top of the water.
It is able to hamper the movement of boats on the water. It can also clog
fishing nets and other fishing equipment. Other problems that Kariba weeds can
cause include the ability to clog water in-lets and outflows. Like other alien
invasive species, it can reduce the amount of oxygen in the water and thereby
disturbing the quality of water.
There
is also another invasive alien speices, Pistia stratiotes, commonly called water
lettuce. This is a floating aquatic plant. Its colour is bright green. It has
an oval-shape. This plant is native to tropical areas in Africa and in Asia.
Its mode of seed dispersal is by the wind and water. Its seeds are dispersed by
wind and water. New plants of the water lettuce can also be formed through the
small fragments of stem, root, or leaf. For a healthy growth, water lettuce
needs light, nutrients, and good temperature. In about two weeks. Water lettuce
is a huge problem for fish habitat and an interference fish life. The reason is
that it can clog the motors of boats. It reduces the oxygen levels in the water
since it is able to spread and cover the surface of the water. Once oxygen
level is reduced, aquatic life is affected because it reduces the amount of
food left for other life forms including those of fish.
Hornwort (Ceratophyllum sp.)
Hornwort
is also an invasive alien species worth mentioning in this discussion. It is
common in still or slow-moving freshwater habitats. The plant is green. It does
not have true roots, stems and leaves, like other plants. Rather, it is made up
of flattened shoots. These shoots branch out from a central stem. The floats in
water. It is propagated by substrate. Hornwort is problem for fish habitat.
Since it grows quickly and is able spread much faster, it covers the surface of
the water and blocks sunlight. This reduces the level of oxygen in the water.
This is a big problem to fish because they cannot easily find their way around
to be able to find food. They are also not able to avoid their predators.
Conclusion
Alien
invasive species have been identified to cause a lot of damage to the
environment, which can lead to a huge economic loss to aquatic ecosystems and
subsequently great loss to the state. This is only so, if they are not properly
managed. Governments all over the world, including those in Nigeria and Ghana,
must develop strategies to control them if they cannot be prevented.
Also read:
The characteristics of fish habitats like freshwater, brackish water and marine water bodies
How to identify and describe common fisheries organisms
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