Marine Life Basics
You don't need to be a marine biologist to enjoy identifying what you see while snorkeling. Knowing a few broad groups gives you a helpful starting point for making sense of the wildlife around you.
Cartilaginous Fish
Sharks and rays fall into this group, named for skeletons made of cartilage rather than bone. Look for their sleek, streamlined bodies, the graceful gliding motion of rays, and the swift, purposeful movement of sharks.
Bony Fish
This is the most diverse group of fish in the ocean, with skeletons made of bone and a swim bladder that helps them control buoyancy. Scales, fins, and gills are the easiest features to spot when identifying bony fish while snorkeling.
Invertebrates
Invertebrates have no backbone and come in an enormous range of shapes, sizes, and colors, from sea stars and sea urchins to jellyfish and coral polyps. Taking time to look closely into the nooks and crannies of a reef often reveals invertebrates that are easy to miss at a glance.
Marine Mammals
Dolphins, whales, and seals are all warm-blooded marine mammals, but they haven't adapted to ocean life the same way. Dolphins and whales are fully aquatic, spending their entire lives in water, and surface to breathe through a blowhole, which is what creates the visible spout. Seals, by contrast, are only semi-aquatic: strong swimmers, but they still come ashore regularly to rest, breed, and avoid predators, so seeing one hauled out on rocks or a beach is completely normal, not a sign something's wrong. Look for a dorsal fin or a spout to spot dolphins and whales, and flippers or a rounded head bobbing at the surface for seals. Keep a respectful distance and observe quietly either way, getting too close can disturb their natural behavior, in the water or out of it.
Watching Responsibly
Identifying marine life is more rewarding when you observe without disturbing it. Keeping your distance, moving calmly, and letting animals behave naturally around you leads to better sightings and less stress on the wildlife. See Coral, Conservation and Responsible Behavior for more on responsible underwater behavior.
