National Park Service

Pacific Island Network (PACN)

Anchialine Pool Monitoring

Anchialine pool at Puʻuhonua o Hōnaunau NHP
Anchialine pool at Puʻuhonua o Hōnaunau NHP

Features & Briefs

The PACN anchialine pool monitoring protocol is under development

For more information contact: Sheila McKenna

Description & Rationale

Video: Where the Sweet and Salty Waters Meet in Hawaii - Anchialine Pools

Anchialine pools are unique brackish water environments that form in lava fields near the ocean. They are landlocked pools fed by subsurface groundwater (freshwater) and tides (seawater) with no visible connection to the ocean. Anchialine pools vary significantly in size and structure from large fishponds to small lava cracks. Hawaii is the only state with these special pools.

Anchialine pools provide critical habitat for rare invertebrate species including shrimp, snails, and damselflies. Many of these species are endemic to the Hawaiian Islands, meaning they exist nowhere else in the world. Anchialine pools face a multitude of threats which threaten their unique animal populations, from exotic species introductions to coastal development and habitat destruction. Pacific island national parks are working to protect some of these last remaining habitats vital to Hawaii's natural and cultural history.


Monitoring Objectives

  1. Determine long-term trends in the composition and diversity of target species of native and introduced fish and invertebrates in selected anchialine pool communities.
  2. Determine long-term trends in the distribution and abundance of native and introduced fish and invertebrate target species populations in selected anchialine pools.
  3. Improve understanding of relationships between anchialine pool animal communities and nearby habitat management by correlating physical and chemical habitat measures with changes in distribution and abundance of fish and invertebrates.

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Last Updated: May 12, 2017 Contact Webmaster