Capesize bulker spot rates have continued their slow decline amid market uncertainty as Brazil boosts iron-ore output, sector experts said.

The capesize 5TC, a spot-rate average weighted across five routes, has fallen steadily since 24 May, registering a 40% slide to $19,845 per day on Tuesday, according to the Baltic Exchange.

"We are sub-$20,000 now on capes, which to me is not surprising," John Kartsonas, founder of asset management advisory firm Breakwave Advisors, told TradeWinds.