Tide Pool Fish

Sculpins resting on bottom of pool
Sculpins are very well camouflaged in algae and tidepools There are 5 Sculpins in this picture Sulpins

Sculpins, Blennys and Gobies

Sculpins are common in tidepools. There are several species of sculpins that live in the tidepool area and are difficult to distinguish. Surveys indicate that half of all tidepool fish in Southern California are Woolly Sculpins. They are very well camouflaged and difficult to observe unless they move. Most often visitors will see a swirl of sand as the small fish swim away into a safe hiding place. Sculpins are slender fish ranging from an inch to 3-5 inches for an adult. There color ranges from brown, grey, green and many shades in between.

Feeding – Sculpins will eat nearly any small invertebrate they can fit into their mouth. This includes snails, crabs, worms, shrimp and many other small animals. These fish are ambush predators in that they sit and wait for prey items to pass by. They quickly swim out and grab their prey and settle back to the bottom and begin the process again.

Protection – Sculpins have a variety of predators including birds and larger fish. Sculpins have two primary means of protection. The first is camouflage. They blend in very well to their surroundings making it difficult for predators to spot them. Sculpins can change their color to match the color of their surroundings. Sculpins can also dart away to a safe hiding place when predators threaten them.

Ecology – This group of fish spend their entire lives in small tidepools. Younger fish tend to move around between tidepools more than adults. Young and adult fish will move to different tidepools as needed based on the availability of shelter and food sources.

As the tide retreats, the fish will be trapped in pools of sea water for a period of time. As time goes by, the water temperature and salinity ( saltiness of the water ) will increase due to the exposure to the sun and resulting evaporation. This would kill most fish. These fish have adaptations that allow them to withstand quick changes in temperature and salinity.

On occasion, Sculpins will become trapped in a tidepool and cannot escape by swimming out on the high tide. Some fish of this group can also breathe air for a period of time if they find themselves in this situation. This allows the fish to move to a different pool of water if conditions in their current pool become dangerous.

Opaleye ( Girella nigricans )

Opaleyes are the second most common fish found in tidepools in the southern California area behind the woolly sculpin. Juvenile Opaleyes will live in the tidepool area until they are large enough to survive in the kelp forest and rocky underwater areas. Juvenile fish are typically darker green and grey in color and have a pair of white spots on the back.

Feeding - Opaleye feed on algae in the tidepool areas. They will also prey upon smaller invertebrates that are available in the tidepool area.

Protection – These fish rely on speed and agility to avoid predation. The juvenile fish will stay close to cover including rocks, cracks and algae mats. When a predator approaches, they will dart to a safer area. The primary predators for Opaleye are larger fish and birds.

Ecology – Opaleye juveniles will live in the rocky tidepool areas for protection. Once they reach a certain size they will tend to live in deeper water. Juveniles in tidepool areas can frequently be seen forming small schools.
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