Sharks are most abundant in oceans because they are marine creatures that have adapted to live in saltwater environments. Oceans provide a vast and diverse habitat for sharks, with a wide range of food sources and suitable conditions for their survival. They have evolved over millions of years to thrive in the open waters of the ocean, making it the ideal location for their abundance. Rivers, lakes, ponds, and creeks, on the other hand, typically do not provide the necessary conditions or resources for sharks to thrive, which is why they are not as abundant in these freshwater environments.