Lehua Islet is a secondary tuff crater (Palmer 1937) 1.2 kilometers off the northern point of Ni‘ihau, Hawai‘i (Fig. 1). Recent publications on Lehua’s avifauna (VanderWerf et al. 2007), Coleoptera (Ramsdale and Samuelson 2006), land snails (Cowie and Wood 2008), and flora (Wood and LeGrande 2006) have demonstrated the biological importance of this 1.1 km2 islet. Conservation efforts for Lehua include recent rabbit removal (Keitt et al. 2006), vegetation monitoring (Eijzenga 2006), and strategic planning for rodent control (OIRC 2008). A native plant restoration project is underway, being spearheaded by the National Tropical Botanical Garden (NTBG) with assistance from members of the Offshore Islet Restoration Committee (OIRC) and under the direction of the U.S. Fish and Wildlife Service (USFWS), Honolulu, Hawai‘i office.
There are several localized currents that are prevalent around Lehua most of the year. Off the northwest side the current travels due north then curves north-northwest off the western horn. There is also an easterly current that travels in the Lehua channel between Lehua and Ni‘ihau. These currents, along with minimal rainfall which normally decreases visibility with excessive substrate runoff, contribute to very clear water conditions. Water depths around the islet increase rapidly with 40 m depths within 10 m of the coast, and >100 m depths within 500 m of shore on the western and eastern sides of the islet. Water visibility is rarely <15 m and frequently >30 m.
To further our understanding of species richness and abundance around the waters of Lehua we present the following annotated checklist of marine mammals and sea turtles observed within five hundred meters of the islet. Nine species are included, three of which are federally listed as Endangered, and two of which are federally listed as Threatened (Table 1).
Citation:
Bane, C., R.W. Baird, and K.R. Wood. 2010. Annotated Checklist of Marine Mammals and Sea Turtles, Lehua Islet, Ni‘ihau, Hawai‘i. ‘Elepaio 70: 49-55.
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