A 7.8 magnitude earthquake struck the South Island of New Zealand on Nov. 14, with the small, coastal town of Kaikoura receiving the maximum, highly destructive release of energy, affecting both residents and the abundant marine life in the area. The quake began just after midnight and lasted over five minutes, causing two deaths: one from a heart attack, and one from a collapsed house. Since the initial quake, more than sixty aftershocks with a magnitude of or greater than 4.5 have been recorded, according to CNN, with hundreds of smaller shocks adding to the count.
The mountains in and near Kaikoura are extremely close to the ocean, so many of the roads run right between the steep mountain slopes the coast; the violence of this earthquake caused massive landslides, sealing off many of the already-narrow roads into Kaikoura with tons of soil and boulders. Roads that weren’t obstructed by landslides were still inaccessible due to tremendous cracks in the cement, so food, water, and other supplies had to be helicoptered in to aid residents; running water wasn’t restored to the town until Nov. 21. While some roads have been cleared, small magnitude earthquakes continue to shake the area, with twenty-five quakes counted on Dec. 6 alone.
Kaikoura is home to a vast array of unique marine organisms, including whales (both resident sperm whales and seasonal blue whales, humpback whales and orca), marine birds and dolphins (Dusky and Hector’s), many of whom are both endemic to New Zealand and have been impacted by the earthquakes. Moving tectonic plates near a fault line caused a shift along the coastline, raising the seabed 0.5-2 meters in some places, which proved deadly for much of the shellfish, coral and kelp attached to rocks by exposing them to air for much longer than they are meant to experience.
Dr. Michael Blanpied, associate coordinator for the USGS Earthquake Hazards Program explains: “Some of the animals that have been raised will be accustomed to air exposure for short periods of time, but not the full tidal cycle that they will now experience. As the animals not suited to this environment die from the reef, they will be replaced by seaweed and animals appropriate for the new tidal level.” Waipapa Bay, located in the southeastern tip of the South Island, experienced coastal uplifts of nearly 6 meters. On the morning of Nov. 14, a few residents of Kaikoura acted quickly upon realizing that beds of paua, abalone sea snails with beautiful shells, were totally exposed to air by filling buckets with the shellfish and depositing them in the receded waters.
Geologically speaking, the coastal uplifts are nothing new for New Zealand, as its mountains were formed over the years through this process, yet it still places many already-endangered species at higher risk. For example, a large colony of New Zealand Fur Seals make their home at Ohau Point, near a small waterfall baby seals used as a play area, which was a popular spot to observe them from a close, yet safe distance. A landslide filled in the pool and destroyed the surrounding area, but some seals have been spotted recently on the beach. Additionally, the endangered Hector’s dolphins, the smallest dolphin species, reside only along the east coast of the South Island and could be acutely affected by the earthquake and its impact on the bathymetry of the area.
Kaikoura’s abundant marine life is due to its deep underwater canyon that houses a provides nutrient-rich water through an upwelling process. Scientists and residents had been concerned that the earthquake may have hurt the canyon and subsequently influenced the marine food chain in the Bay when no whales were spotted for days after the Nov. 14 quake. However, the return of the resident sperm whales, beginning on Nov. 19, lends confidence that the marine life around Kaikoura will continue to thrive, regardless of any changes to the canyon or reefs along the Kaikoura coast.
