Thousands of marine animals have been found dead along the Wairarapa coast near Cape Palliser following last weekend’s severe storm, local observers and experts say. Reports indicate tens of thousands of paua, octopuses, starfish, and crayfish were discovered in large piles of debris on beaches northwest of Cape Palliser.
The storm caused widespread disruption across the Wairarapa region, including floodwaters discharging into the sea and damage to infrastructure, notably a washed-out bridge near Lake Ferry. The influx of fresh water from flooded rivers is believed to have played a key role in the mass die-off.
Andrew Sim, a commercial fisherman based in Ngawi with more than 40 years in the area, estimated the scale of the loss at tens of thousands of animals. Sim described the event as a “total wipe-out” of inshore stocks, attributing it to the overwhelming presence of fresh water and silt that buried marine life along the coast. He noted that female crayfish with eggs were among the casualties, underscoring concerns about the ecological impact. Sim pointed to a stretch from Shag Rock roughly three to four kilometres long as severely affected, adding that the visible destruction likely represented only a portion of the total area impacted.
Specific locations hit hard include the mouth of the Otakaha Stream, where sediment and debris have altered the shoreline, creating new sand formations extending into the ocean. Sim indicated that such a widespread event of this magnitude had not been observed in more than 30 years, with significant damage noted near “The Washpool” on Cape Palliser Road, north of Whatarangi Bluff.
John Priest, who operates Waimeha Camping Village a few kilometres west of Cape Palliser, confirmed that dead paua were the most common marine animal washed ashore, accompanied by octopuses, starfish, and crayfish. He described beaches piled with vegetation and debris that had come down rivers during the storm, burying many of the dead animals.
Marine biology expert Dr. Christopher Cornwall, senior lecturer at Te Herenga Waka/Victoria University of Wellington, explained that the deaths resulted from the storm’s heavy rainfall introducing large amounts of fresh water into the coastal marine environment. Freshwater decreases salinity, which can severely stress marine organisms that rely on stable saltwater conditions for survival.
Paua, in particular, are sensitive to changes in salinity. Under normal conditions, paua can reorient themselves if turned over, but exposure to fresh water impairs this ability, leaving them vulnerable to being washed ashore. Cornwall noted that starfish, crayfish, and octopuses experience similar stress and loss of grip on reef surfaces under such conditions. He highlighted that the combination of freshwater influx, heavy wave action, and sediment burial results in many marine animals being stranded and dying onshore.
“This type of fresh water input can have massive impacts on marine ecosystems, which is apparent in the situation unfolding along the Wairarapa coast,” Cornwall said.
The event underscores the vulnerability of coastal marine life to extreme weather and environmental changes, particularly in regions prone to heavy rainfall and flooding.