Green crab (Carcinus maenas)

Carcinus maenas better know by its common name green crab is originally native to Europe and is now dispersed globally with records of occurrence in Australia, Hawaii, Sri Lanka, South Africa, along the Atlantic and Pacific coasts of North America, and the Atlantic coast of South America

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 It was first introduced into the U.S in 1817 by ship's ballast water  and is now the most abundant crab species with the females being able to produce up to 185,000 eggs per sponge.Green crabs eat a wide variety of prey organisms and can significantly reduce populations of native clams and crabs in areas where they have become established. Their ability to out compete native species for food resources, high reproductive capacity, and wide environmental tolerances lend them the capacity to fundamentally alter community structure in coastal ecosystems. Their main prey ranges from clams, mussels, oysters and gastropods. 

The economic cost of these invasive species are very high as they reduce the native species populations and reduce income of fisher men who depend on the ocean to live.

Zebra mussels (Dreissena polymorpha)

Zebra mussels also know as Dreissena polymorpha got their name from the stripped pattern on their shell but it also varies and causes there to be no stripes and just light or dark colored shells.

They are native to Russia and were first introduced into the United States in the 1980's by transoceanic ships from western European ports discharging ballast water into lake St. Clair. Since their arrival zebra mussels have disrupted the natural  aquatic food chain of many bodies of water, also just like other mussels zebra mussels attach to hard surfaces like pipes

 and also the native mussels.

 with the spreading of these mussels the population of native mussels have severely reduced.
There are now  millions of these mollusks, and they have a rapid rate of reproduction and paired with no natural predator their numbers flourish.

Lion fish ( Pterois volitans )

The red lion fish also know by its scientific name Pterois volitans is an IAS or invasive Alien Species meaning it is not native to our region. It is native to the Indo-Pacific  region of the ocean. It arrived in Trinidad and Tobago in late 2010, and has reportedly spread to 14 countries in the Caribbean with sightings in Tobago, the Turks and Caicos Islands to St. Croix and in both Central and South America, Belize Curacao and in Venezuela. It's rapid spread in the Caribbean is due to lack of natural predators in its new habitat , which means the numbers are left to grow out of control and the native species is endangered because they don't share an evolutionary history that would have allowed them to have defensive mechanisms.

  

It is a gluttonous predator because adult lion fish are primarily fish-eaters and since they predators outside of their home range researchers state that a single lion fish residing on a coral reef can reduce the native reef fishes by 79 percent. Because lion fish feed on prey normally consumed by snappers, groupers, and other commercially important native species, their presence could negatively affect the well-being of valuable commercial and recreational fisheries.

The population of the lion fish spreads rapidly it has a life span of 16 years and reach maturity very quickly at lengths of 10cm for males and 18cm for females. Reproduction is sexual and results in 15,000 mucus encapsulated eggs. The females can breed every 4 days, with the larvae emerging after 36 hours and 2-3 days for them to become capable swimmers.