Our Study Site - Ka'ena Point State Park

Aloha everyone! I would like to tell you all about the beautiful location our shells were gathered from.

 

Ka'ena Point, the western-most point of O'ahu.

Ka'ena Point State Park is located on the dry, western-most point of O'ahu, and features two beautiful hiking trails. The Keawa'ula Trail was once a railroad that ran along the western coast of the island. Today, this abandoned railroad trail allows visitors to hike on foot along a beautiful shoreline. In the early mornings, it is common to see monk seals (in Hawaiian, called "ilio-holo-i-ka-uaua", meaning "dog that runs on the water") resting by the water, and in the winter months it allows a view of visiting humpback whales (in Hawaiian, called koholā").

 

Two monk seals resting along the shoreline of the Keawa'ula Trail.

The Keawa'ula Trail towards Ka'ena Point is approximately 2.7 miles (4.3 km) one-way, and takes approximately two hours to hike to the Ka'ena Point protected bird sanctuary, which makes up the end of the trail. The hike is hot and dry with no shade. On one side of the trail is the beautiful ocean, and on the other is a cliff face composed primarily of lava rock.

 

A view from the Keawa'ula Trail. On the left is one of our deposits, and on the right is the ocean. The trail is hot, and sunscreen and a sun hat are highly recommended.

Our study has us collecting shells from deposits (death assemblages) located along the Keawa'ula Trail, approximately three-quarters of the way towards the end of the trail. Our deposits are located just off the trail, within view of the hiking trail. However, our shells are so small (only a few millimeters in length and width) that most people pass them by without noticing!

 

One of the deposits where we gathered shells in Summer 2021. Shells are embedded within the stone and are eroding out of it. This deposit is light in color because it is composed primarily of calcium carbonate and limestone, two components that snails use to construct their shells.

Hawaiian land snails today (with rare exceptions) require wet and cool environments for their survival, and live on very specific, native Hawaiian host plants. However, Ka'ena Point today is a hot and dry environment with sparce vegetation that grows low to the ground. The discovery of land snail shells in this area was striking, and leads us to hypothesize that this location may have been very different in the past. Our study will allow us to reconstruct the past environment of this area, and "see" what the environment was like for these snails!

Thank you for reading and for your support! Mahalo!