Invasive Species Introduced To Marine Ecosystems
Planet Earth as we know it is constantly evolving, developing and shifting in different ways due to both natural and man-made causes. These paradigm changes in nature can be driven by changes in climate, nitrogen eutrophication, and augmented urbanization as stated by Davis et al. 2017. As a consequence to some of these variations, we have seen terrestrial and marine ecosystems being subject to harmful invasions of non-native species.
Invasive species, describing any group of organisms that have migrated from their native area(s) to foreign grounds and caused economic, environmental or human harm, have been an increasingly popular threat to endangered species – both on land and water (Hill 2014). Researchers per National Geographic have studied the ongoing invasion of the Indo-Pacific-native Lionfish species and its harmful effects on Atlantic-native organisms and ecosystems in the coastal waters near Florida. By reproducing very early and often in life and dispersing its eggs and larvae over wide ranges which ride into vast nearby ocean currents, the carnivorous lionfish is a classic example of a non-native species that has posed as a major threat to many marine ecosystems. These fish are successful invaders that disrupt other fish because they eat a variety of native species in Florida (such as snappers and groupers) while also not having any natural predators due to their venomous spines (Friedrich, National Geographic). Lionfish pose as direct predators to both carnivorous and herbivorous fish who serve a huge role in keeping the ecosystem intact, thus there has been recent pushes and policies to increase fishery removals of lionfish in the areas.
Another example of a fierce invasive species introduced to marine ecosystems in the Atlantic and Eastern Pacific Ocean near North America is Gracilaria vermiculophylla, an East-Asian-native red alga that has overtaken and out-competed many other native algae because of its versatile ability to grow in almost any type of marine climate (Thomsen & McGlathery 2006). G. vermicuophylla has been investigated for many years as a successful invasive species, and more and more research has indicated how much of a negative impact this species has had on marine environments because this alga inhibits the growth of other essential algae and is able to develop dense layers that can modify available marine habitats for fish and other species in the benthic zone (Nyberg et al. 2009). Scientists fear that the invasion will only worsen as global water temperature continue to rise (Global Invasive Species Database).
In relevance to our region, the country of Australia has seen an abundance of non-native species invading ecosystems throughout its vast territory, and invasive species are now considered the number-one threat of extinction to organisms in Australia (Sheppard & Broadhurst 2019). Invasive species are also close to 60% higher in Australia versus the whole rest of the globe as indicated in the figure below (Kearney et al. 2018), which implies that measures must be taken to protect diverse and perhaps endangered marine life.
Furthermore, researchers from the CSIRO have detailed the increasingly harmful impacts of invasive alien species in Australia and their implications on multiple aspects of society. Not only do invasive species threaten native organisms by consuming them directly, they also out-compete them for prey. Both of these features directly impact the biodiversity of marine life ecosystems, which is essentially a cultural issue because more than 70% of Australian species are only found in Australia alone and no other areas of the world (Sheppard & Broadhurst 2019). Implications on human health involve the fact that invasive species can contaminate drinking water and oxygen affecting humans in their respective parts of the world, while economic concerns include how some aquaculture diseases have impacted oyster and prawn habitats costing prawn fisheries nearly $40 million (Locke & Silva 2017).
Can there be any benefits from invasive species in marine ecosystems? Some ecologists think so and are hesitant to remove non-native organisms from foreign areas until there is substantial evidence that they have caused environmental harm (Davis et al. 2011), but others believe that constant maintenance checks and measurements must be performed on newly introduced non-native species because sometimes these foreign species look as if they are benefitting other species at first, but overtime can be detrimental to entire ecosystems (Simberloff 2011).
All in all, it is vital that public and governmental policies are put in place to mitigate some of the damaging impacts that invasive species have on marine ecosystems. We must encourage fisheries to remove these invasive species in big fractions and even encourage human consumption to generate a fiscal incentive for farmers and fishermen. If measures aren’t taken, we will continue to see ecosystems be overcome by harmful species and we may in fact lose more of our amazing marine biodiversity to extinction.