Some vessels have recently paid over $1 million in auctions to secure transit slots through the Panama Canal, the canal authority reported Tuesday, attributing the situation to changes in global trade supply and demand.

The Panama Canal Authority (ACP) indicated that the high bids reflect temporary market fluctuations and not increases in the established tolls for the interoceanic waterway.

While median auction prices averaged around $55,000 between October and February, recent strong demand has pushed median prices to roughly three times that level, according to the authority.

"Auction values are determined by multiple factors, including each customer's urgency and commercial priorities, as well as overall supply and demand conditions," the ACP stated in a release.

To conserve water, the canal will limit daily transits to 34 vessels starting September 4, and will reduce the limit to 32 vessels on September 15.

Unlike the Suez Canal, which operates at sea level, the Panama Canal uses a gravity-fed lock system that depends on fresh water from Lake Gatún and Lake Alajuela. The El Niño climate phenomenon has reduced seasonal rains needed to replenish these reservoirs, forcing the authority to restrict traffic.

To avoid delays or high auction fees, some shipping lines are rerouting routes around the Cape of Good Hope in Africa. Approximately half of U.S. liquefied natural gas (LNG) carriers bound for Asia chose that route in August, extending the typical voyage from Houston to Japan from 26 to 45 days.