Feeding Activity

Blue Runner
Atlantic Spadefish

- apex predator, feed on most fishes smaller than itself
- feed in large schools
- quick, efficient predators

- juveniles often feed in water column
- may feed in large schools

- feed on slow prey - jellyfish and invertebrates
- can move in bursts of speed, but are slower predators

An assemblage of reef fishes contains some fish species (forage fishes) that feed on plankton or benthic invertebrates . These forage fishes, in turn, support apex predatory fish (piscivorous species) that feed on other fish. (fish that feed on benthic inverts are predators too!) Without the forage fishes, which can be the juveniles of other species, the larger piscivorous (fish-eating) fishes must move to other areas to feed. Seasonal increases in plankton productivity support increased abundance of plankton-feeding forage fishes. The planktivorous species help transfer energy to the bottom feeding fishes, in the form of feces that sink to the bottom and increase productivity of benthic worms and crustacean that are fed on by bottom-feeding foragers. The populations of plankton-feeding (planktivorous) and bottom-feeding (benthivorous) fishes in turn support seasonal populations of piscivorous blue runners and other jacks, and even migratory seabirds such as loons.

The two most important activities for fish survival are growth (though feeding) and reproduction. Both feeding and avoiding being eaten are critical to the growth and survival of individuals, while reproduction is most critical to survival of a population of animals. Fish growth can often be seen by the changes in size of juveniles over time. Fish biologists very rarely observe reproduction activities (“spawning”) of fish, which often is associated with sunset or nighttime, but they do observe feeding, if they are fortunate. Some of these life activities have been recorded by the Fish Watch cameras. Hopefully more of the activities of fishes at the reef will be observed and archived for your interest and enjoyment in the future.