What caused mass deaths of marine animals washing up on the Napier coastline in recent days is still unclear.
Scientists have a theory but are continuing their investigation on the water.
Large numbers of marine species including crayfish, kina, starfish, and sea cucumbers have been washing up on Ahuriri beach.
Michael Newton lives beside the beach and said the beach was covered.
“It was crazy, I've never seen anything like it before, to see how much was going to waste and died off was really sad.
“It was just a real pungent smell, it just littered the beach, and it kept washing up in every wave,” Newton said.
Hawke’s Bay local Samuel October said it was a bad look for the town.
“I felt quiet down in a way, seeing all the wasted seafood go to waste.
“How much seafood there was that washed up was quite a shock for the whole community,” October said.
Hawke's Bay Regional Council has been taking water samples along the coastline to check if it's an isolated event or more widespread.
Senior scientist of marine and coast Becky Shanahan said the working theory from recent results point to algae bloom that has been sitting on the coast for weeks.
“When the algae bloom dies, the algae sink to the bottom, they decompose, and they suck up oxygen in the process of doing that.
“The readings we got after the animals washed up showed some pretty low dissolved oxygen levels, normally expect the surface to be 90 to 100% and we were getting much lower readings at the surface and even at the bottom as low as 20 to 30%.
“Testing today and the measurements today indicate that it was more a localised issue but we won’t know for sure until we get some samples back from the lab,” Shanahan said.
Heavy rain mixed with warm humid days is when algae bloom can appear, they feed off the nutrient-loaded fresh water mixing with salt water.
With more rain and warm weather on the way, Hawke’s Bay Regional Council advises caution around swimming and not to eat any of the washed-up kaimoana.
Other theories are being considered including sediment smothering or a toxic spill.
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