Wildlife & Habitat

Red footed boobies

Johnston Atoll is located some 450 nautical miles SW of French Frigate Shoals, its closest neighbor in the Hawaiian Islands National Wildlife Refuge. As a result, Johnston and French Frigate Shoals may have played important roles as stepping stones for the migration of marine species between Hawai‘i and the Line Islands to the south. Johnston Atoll is an oasis for reef and bird life and may be the most isolated atoll in the world.

  • Birds

    Great frigatebird

    Seabirds are the most noticeable form of wildlife on the Refuge and are among the longest-lived birds in the world; life spans in excess of 30 years are common for some species. Shearwaters and petrels belong to a highly distinctive group of marine birds that are readily identified by their hooked bills and also by their nostrils, which are sheathed in horny tubes arising near the base of the bill.

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  • Mammals

    Bottlenose Dolphin 150x90

     Most marine mammals are visitors outside Johnston Atoll and occasionally to lagoon waters.

     

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  • Reptiles

    Green turtle

    Green turtles have been historically recorded at Johnston Atoll. They nest and bask on beaches when available. It has been estimated that approximately 200 green turtles have utilized the south shore of Johnston Island for a feeding ground. This area has one of the highest concentrations of green sea turtles at a non-nesting foraging ground in the Pacific.

     

  • Fish

    Chaetodon Ornatissimus

    Approximately 300 species of fish have been recorded in the near shore waters and reefs of Johnston Atoll. This number is smaller than that of other islands in the Central Pacific is likely due to Johnston Atoll’s small size and remote location. One species of angelfish, Centropyge nahackyi, is endemic (i.e., characteristic of an area or environment) to Johnston Atoll  

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  • Invertebrates

    Praying Mantis 150x105

    The invertebrate marine fauna at Johnston Atoll includes Porifera (sponges), Cnidaria (jellyfish, anemones, corals), Aschelminthes (pseudocoelomate worms, e.g., roundworms, ribbon worms), Polychaeta (segmented worms), Sipunculida (peanut worms), Crustacea (e.g., lobsters, crabs, shrimp), Mollusca (e.g., octopus, clams, snails), Bryozoa (moss animals), Echinodermata (e.g., starfish, sea urchins), and Ascidiacea (sea squirts)

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  • Marine Habitat

    Acanthurus Triostegus and coral

     The marine environment around Johnston Atoll consists of a shallow coral reef platform encompassing approximately 50 square miles. Johnston Atoll is unlike most coral reef atolls: the protective ridge of coral reef extends only along the northwest side due to its underlying platform subsiding and tilting southeast. The lagoon ranges in depth from 10 to 32 feet. The platform slopes gently to 23 to 59 feet, then much more steeply to 590 feet. Most of the reef lies outside the lagoon, extending approximately 11 miles east-southeast and 5 miles south of Johnston Atoll. 

     

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  • Island Habitat

    Johnston 150x100

    Johnston Atoll underwent two landmass enlargements that were supported by dredge-and-fill operations in the lagoon. The first enlargement occurred in 1949–1950, the second in 1963–1964. This resulted in the landmass being increased to 1 square mile (with four islands) from its original mass of 0.07 square mile (with two islands, Johnston and Sand).

     

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