Save your money and frustration. I had long email exchanges with Splash. I was promised that their boats - well here's Ralph's exact words -
“We use two methods to look for whale sharks – looking for the snapper or looking for the birds.
1. We use fish finders to find the snapper as the whale sharks come to feed on the spawning aggregation and put the divers in the water above the snapper. The divers try to stay with but well above the snapper and try to stay in a tight group so that the bubbles are concentrated. The idea is that the whale shark will see the bubbles, think that is the spawn and come directly to the divers. As the bubbles go to surface, often the whale sharks do too, so the snorkelers get a close encounter. We have had some situations where the whale sharks came from the side rather than from the deep, so the snorkelers saw them but the divers who were looking down, did not see them. Other times, the whale sharks have come close to the divers and then gone back down without tasting the bubbles.
2. We watch for birds circling as when they flock over the sea, it is usually because they are feeding on bait fish. Whale sharks also feed on bait fish and they do that on surface. When we see the birds, we head for the spot. Usually in this situation, the divers tend to stay at snorkel depths..”
Lies. I expressed multiple times that this was a top of the bucket list trip for me - why did you lie to me Ralph? The boat has a 1.5 hour window in the "whale shark zone". Splash drops you into the open ocean and the DM (who was every bit as pi$$ed as me re the situation) swims randomly trying to find a school of fish, that might be spawning, that might attract a whale shark. Yeah right! No sonar (confirmed by both the DM & ship captin), no GPS, no looking for birds. No communication with other boats.
Ukrainien proverb - (cleaned up a bit) Pee in one hand and wish into the other - see which fills first. The DM confided that the Belize goverment is trying to close the "whale shark zone" for 2-3 years in the hope that they can lure them back.
I was told by other divers that Ambergris Cay was a lot better. Given the marine life after an hours pounding boat ride I'm not sure that is much of a recomendation.