Invasive species are impacting environments and ecosystems worldwide, but ocean invaders are particularly detrimental. Once an aquatic invasive species takes hold in a harbor, lake, or reef, removing it becomes slow and costly, and biologists, resource managers, and aquaculture professionals must understand how these species move and what stops them. At Unity Environmental University, the B.S. in Marine Biology and Sustainable Aquaculture builds that understanding through coursework on how marine and farmed organisms grow, spread, and stay healthy.
The Silent Invasion: What Makes an Aquatic Species Invasive
According to the U.S. Department of Agriculture’s National Invasive Species Information Center (NISIC), invasive species are non-native plants and animals that live in areas where they do not naturally exist and have the potential to significantly disrupt the ecosystem. In a new ecosystem, many invasive species have no natural predators and can reproduce frequently, overtaking the habitat. This then affects the food sources and living spaces of native species that have long called that environment home.
Invasive species threaten biodiversity in local ecosystems and can also harm human health and economies worldwide. That said, invasive species in the ocean are particularly challenging because they can spread rapidly through interconnected waterways.
How Invasive Species Spread Through Oceans and Waterways
Marine invasive species can enter new, non-native environments through a handful of pathways, nearly all tied to human activity. Understanding these methods is key to preventing their spread and protecting marine ecosystems.
- Ballast water: As one of the most common pathways of invasive species in the ocean, ballast water from freighter ships inadvertently carries non-native species from port to port and releases them far from their point of origin.
- Aquaculture and aquarium trade: Fish farms and aquarium facilities can release non-native species into local waters when animals escape or when unwanted aquarium pets are dumped into open water, disrupting local marine ecosystems.
- Recreational boating and fishing: Even smaller vessels, such as recreational boats and fishing fleets, can transport invasive species between bodies of water, and mariners now travel farther than ever before.
- Canals and waterways: Artificial waterways that connect large bodies of water give invasive species an easy path to environments they would not otherwise have had access to.
- Climate change: Rising ocean temperatures allow non-native species to establish themselves in habitats that were once too cold for them to survive, according to National Geographic.
How Invasive Species Affect Aquatic Ecosystems
Invasive marine species can be incredibly disruptive to the local environment. Invasive species outcompete native species, ultimately taking over their food and habitat resources while evading natural predators in that food web. The result is an array of ecological, economic, and human health consequences.
Ecological Impacts
The ecological impacts of invasive species extend beyond the native species and into the ecosystem itself. The most significant ecological impacts of invasive species in the ocean include:
- Predation: Invasive predators can significantly harm native populations, increasing the risk of extinction for prey species, as lionfish have shown on coral reefs throughout the Atlantic Ocean and the Caribbean Sea.
- Competition: Invasive species can outcompete native species for resources.
- Habitat Alteration: The activity and lifestyle of invasive species can change the physical structure of local habitats.
- Disease Transmission: Invasive species can introduce new diseases to populations within the ecosystem.
Economic Impacts
The economic impact of invasive species worldwide is surprisingly significant. A 2021 study cited by NISIC found that invasive species have cost North America more than $26 billion per year since 2010, up from about $2 billion per year in the early 1960s. Marine invasive species affect the economy by damaging local aquaculture and reducing fishery yields, clogging waterways and damaging infrastructure that must be repaired, and increasing the cost of managing and controlling invasive populations.
Zebra and quagga mussels show how far those costs can travel. Since arriving in the Great Lakes in the late 1980s, zebra mussels have spread to 31 states and quagga mussels to 18, according to the U.S. Geological Survey (USGS), and both clog the intake pipes of power plants and water treatment facilities.
Human Health Impacts
The National Invasive Species Information Center notes that some invasive marine species can threaten human health and well-being by acting as vectors for new diseases or injuring humans through bites or venomous stings. They can also indirectly affect human health by disrupting ecosystems that typically provide clean water and nutritious food.
How Scientists Prevent and Control Aquatic Invasive Species
Recognizing the far-reaching consequences, scientists, resource managers, and government agencies are working together to combat invasive species in the ocean and worldwide. That work unfolds in three stages, and each one depends on a different set of scientific skills.
Prevention
Some of the preventative measures being taken to curb the spread of invasive species include:
- Imposing stricter regulations on ballast water management
- Improving biosecurity measures in aquaculture
- Expanding public education and outreach
Early Detection and Rapid Response
Intense monitoring and surveillance also enable early detection and rapid response. When an invasive species is discovered, rapid response teams work to contain new populations before they can become well established. Speed matters here, because an invasive population becomes far harder and more expensive to remove once it takes hold.
Control and Management
Efforts are ongoing to control and manage marine invasive species populations. Control and management efforts include:
- Physically removing invasive species
- Using chemical and biological control methods to reduce population numbers
- Working to restore habitats to promote the recovery of native species
Natural resource managers on land weigh many of the same trade-offs, and our piece on mitigating invasive species through natural resource management covers that side of the work.
The Jobs Behind Aquatic Invasive Species Work and What They Pay
Every stage above depends on trained people, and most of them work in the public sector. The U.S. Bureau of Labor Statistics (BLS) lists estimating, monitoring, and managing invasive species among the core duties of zoologists and wildlife biologists, and about two-thirds of those professionals work in government.
Pay varies by role, so the figures below are BLS national medians for May 2025, matched to the closest occupational category the agency tracks.
| Role | Where the Work Happens | BLS Median Pay, May 2025 |
|---|---|---|
| Fisheries management specialist | State and federal agencies tracking fish stocks and the invasive species that threaten them | $76,780 (zoologists and wildlife biologists) |
| Biological technician | Field and lab crews that collect samples, run surveys, and support removal projects | $57,510 |
| Environmental scientist or specialist | Agencies and consulting firms assessing ecosystem impacts and regulatory compliance | $82,220 |
| Aquaculture farm manager | Shellfish, finfish, and seaweed farms managing stock health and preventing escapes | $89,900 (farmers, ranchers, and other agricultural managers, which includes aquaculture) |
Aquaculture is the role people tend to overlook. The same fish and shellfish farms named as a pathway for invasive species are also where much of the prevention happens. Professionals in this field commonly manage disease control, escape prevention, and the sourcing of healthy stock, all of which keep farmed species and their pathogens out of wild waters.
Unity’s B.S. in Marine Biology and Sustainable Aquaculture builds directly toward that work. Sustainable Aquaculture Techniques II: Crustaceans and Pathobiology covers the causes of disease in aquaculture organisms and the techniques used to control it, while Ichthyology and Fish Health and Global Diversity of Freshwater and Marine Resources Used in Sustainable Harvest ground students in the species themselves. For a wider view of the field these roles sit within, see how to become a marine biologist.
Build the Skills to Manage Aquatic Invasive Species at Unity
Invasive species in oceans and lakes worldwide pose major threats to aquatic ecosystems. Preventing new arrivals and controlling established populations is steady, science-driven work, and it rewards people who understand both wild marine systems and the farms, ports, and waterways that connect them.
Unity Environmental University’s B.S. in Marine Biology and Sustainable Aquaculture pairs marine biology with aquaculture practice across 120 credits, delivered through remote learning with eight terms a year. You can transfer in up to 90 credits, and Distance Education tuition is locked through 2030. If you already hold a bachelor’s degree, the M.S. in Marine Conservation Biology builds on that foundation and moves into research design and conservation strategy in as little as one year.
Request information about the B.S. in Marine Biology and Sustainable Aquaculture and start building the skills to protect the waters invasive species threaten.
Sources
- National Invasive Species Information Center: What Are Invasive Species?
- National Park Service: Invasive Species
- NOAA Fisheries: Invasive and Exotic Marine Species
- National Geographic: Marine Invasive Species
- National Invasive Species Information Center: Environmental and Ecological Impacts
- National Invasive Species Information Center: Economic and Social Impacts
- National Invasive Species Information Center: Human Health Impacts
- Smithsonian Ocean: Five Invasive Species You Should Know
- U.S. Geological Survey: Zebra and Quagga Mussels in the United States (2024)
- U.S. Bureau of Labor Statistics: Zoologists and Wildlife Biologists
- U.S. Bureau of Labor Statistics: Farmers, Ranchers, and Other Agricultural Managers
