In prison he met Wizard/Horace Kates , a Green Arrow foe, and they decided to escape together. Sick and tired of their respective enemies, they also decided to switch vocations. Shark would try his lack as a land-based criminal and Wizard as a seafaring one. They were certain the heroes would not follow them. They were wrong.
The Coast Guard convinced Aquaman to track down Shark on land. By their polite request ” Everybody knows that if you’re out of water for an hour, you gasp for water like a dying fish! But the police feel you alone have the know-how to catch “Shark”!” ” So Aquaman “dons a water helmet”, places his useful sea creatures in a big water tank and loads it to a truck. Then drives said truck in search of land-sharks.