Waves in the area at the time were between half a metre to 1m high, but there were strong rips and currents around Cook Rock and the nearby Brother Islands.
Police said hundreds of search hours were put into finding Walker, including air, shoreline and water searches. Police, SAR teams, Coastguard and the Rescue Co-ordination Centre were involved in the searches.
A jetski, believed to be Walker’s, was found a day after he went missing.
Police said they are continuing to offer support to his family during an extremely difficult time.
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