Seals slowly adapting to post-quake life
It was once one of the most popular attractions on the Kaiko¯ura coastline – an idyllic river pool beneath a waterfall, filled with seal pups at play. That changed on November 14.
When the earthquake struck, the cliff above the pool came crashing down, while tonnes of rock and earth fell from hau Point onto the coast which a large seal colony called home.
It seemed the colony was gone, but one year on, the seals have proved ‘‘remarkably resilient’’ – though dozens have been killed in the efforts to rebuild the crucial road and rail which hugs the coastline.
About 180 bull seals have settled along the coast around hau Point, boding well for the breeding season about to begin. Formerly about 2000 seal pups were born at the site each year.
Department of Conservation (DOC) Ranger Mike Morrissey, who has worked with the seals over 30 years, was one of the first in to the waterfall pool after the quake. He said it was ‘‘no longer a pool, it’s just a mound of rock’’.
Morrissey said the rest of the stream looked ‘‘very similar to what it was before’’ and some pups had been seen in the area.
‘‘They still go up and play in the stream, but obviously just in little wee pools between rocks.’’
Northern South Island operations manager Roy Grose said further rock falls from the cliff beside the waterfall pool were possible. The area would remain closed to public access.
The waterfall pool and track leading to it are on privatelyowned land. Grose says DOC had been in discussion with the land owners but no decision on the pools future had been made yet.
He said seals were still being seen in large numbers around the hau Point area, though many had moved to a new territory slightly to the north.
The Kaiko¯ura seal population seemed ‘‘remarkably resilient to the impacts of the earthquake’’ and subsequent work on the road and railway line that butted up against their habitat, said Grose.
Morrissey said the new habitat further north was ‘‘probably not as good’’ as hau Point was prequake.
Grose said pre-quake there had been several hundred males at the point during breeding season. Numbers peaked in midNovember as many seals spent a lot of time at sea prior to the season, in order to bulk up.
He said it was unlikely the quake’s full impact on the seal population would be known for a few more breeding seasons.
‘‘We will also get a clearer picture of where seals may settle in the longer term once the road construction work is completed.’’
Dozens of seals have died due to the highway rebuild following last November’s earthquake, despite the best efforts of the workers.
In the last three months, the North Canterbury Transport Infrastructure Recovery alliance (NCTIR), who are rebuilding the battered transport corridor, have recorded 41 seal deaths caused by earthworks or road rebuild activities.
A total of 294 dead seals have been found by rebuild workers over the same time period, but the cause of the remaining 253 deaths is unknown – but not thought to be related to the works. It is common for young seals to die in the late winter and spring, usually in a skinny and poor physical condition.
NCTIR environmental manager Manea Sweeney said they were doing ‘‘everything they can’’ to minimise seal deaths throughout the project.
Over 11,000 seals (many repeat offenders) have been moved by seal handlers who are constantly monitoring the coastline outside the ongoing roadworks. In places, a row of 5-tonne seawall blocks have been temporarily laid on the edge of access roads to keep the rare mammals outside the work zone.
She said moving seals involved ‘‘a huge amount of work’’. Teams of seal handlers were working 24 hours a day to matchO¯the schedule of the road works.
Sweeney said NCTIR had a ‘‘robust’’ environmental management framework The environmental team was made up of about 40 people.
‘‘With the sheer scale of it, this could be the largest environmental team on a construction project ever in New Zealand.’’
About 180 bull seals have set up long the coast around hau Point in the lead-up to breeding season.