Invasive Species

Invasive spieces
Ta'ape is an invasive fish found in the waters of the Northwestern Hawaiian Islands. Credit: NOAA

Why is it a concern?

Invasive species can radically alter the diversity or abundance of native species or the ecological stability of infested waters. Additionally,the presence of invasive species should be closely monitored to prevent new introductions. Eleven introduced invertebrate, fish, and algae species have been recorded in the Northwestern Hawaiian Islands.  Their abundance and impact are currently considered low.  Invasive species can enter habitats in a number of ways; unintentionally by vessels, marine debris, or aquaculture, or intentionally, as in the case of some species of groupers, snappers, and algae.  Eleven species of shallow-water snappers and groupers were purposely introduced to one or more of the main Hawaiian Islands in the late 1950s.  Presently, two species, ta’ape (blueline snapper) and roi (peacock grouper) are now established in the Northwestern Hawaiian Islands.  Currently, prevention is the primary activity related to invasive species, and non-indigenous species in general.  Mandatory hull inspections and cleaning, marine debris removal, quarantines for most islands, and monitoring programs are all ways in which the Monument prevents and tracks non-indigenous species.

Populations of alien marine species that have already colonized areas of the main Hawaiian Islands represent the most likely source of invasive species in the Northwestern Hawaiian Islands.  They can be found from littoral zones to deep-water coral beds.  The few alien species known from the Monument are mostly restricted to areas of higher human activity at Midway Atoll and French Frigate Shoals, though two species can be found throughout the Monument – ta’ape and the hydroid Pennaria.  Though not all introduced species will become invasive, these non-native species could still negatively impact native biodiversity, water quality, and nutrient cycling.  


Overview of Research

Project Name PI and contacts Links

Marine debris monitoring and removal

NOAA Pacific Islands Fisheries Science Center (Coral Reef Ecosystem Division)

Human impact monitoring   

Dr. Robert Toonen (University of Hawaii), Dr. Kim Selkoe (National Center for Ecological Analysis and Synthesis)


Invasive species monitoring

NOAA National Marine Fisheries Service (Pacific Islands Fisheries Science Center, Coral Reef Ecosystem Division)

Mesophotic coral ecosystem characterization and monitoring



Science Needs and Questions

  • Which non-native species represent the biggest threat to the Northwestern Hawaiian Islands?
  • How often and where are invasive species coming into the Northwestern Hawaiian Islands?
  • What are effective controls for marine invasive species?
  • Are the invasive species already established spreading, and if so, at what rate?
  • What are the environmental conditions or other factors in which alien species may become invasive?

Education and Outreach Material

The Monument engages users and the public in preventing the introduction and spread of alien species by integrating alien species information into outreach programs for permittees and integrating alien species information into general outreach materials.


PMNMS Invasive Species Science Need