Ichthyoplankton

Ichthyoplankton are the eggs and larvae of fish. They are usually found in the sunlit zone of the water column, less than 200 meters deep, sometimes called the epipelagic or photic zone. Ichthyoplankton are planktonic, meaning they cannot swim effectively under their own power, but must drift with the ocean currents. Fish eggs cannot swim at all, and are unambiguously planktonic. Early stage larvae swim poorly, but later stage larvae swim better and cease to be planktonic as they grow into juveniles. Fish larvae are part of the zooplankton that eat smaller plankton, while fish eggs carry their own food supply. Both eggs and larvae are themselves eaten by larger animals.

Life Cycle

Fish reproduce by either laying eggs or giving birth to live young. Those that lay eggs release them into the water, where they are fertilized. The fertilized eggs then become part of the plankton, floating at the mercy of the currents until they hatch into larvae. The larvae continue to float in the plankton until they develop into juvenile fish, at which point they are capable of swimming against the current and can leave the plankton to join the adult fish population.

Ecology

Ichthyoplankton make up a significant portion of the marine food web. They are a primary food source for a wide variety of marine animals, including other plankton, fish, birds, and mammals. Because of their importance in the food web, changes in the abundance and distribution of ichthyoplankton can have significant effects on marine ecosystems.

Research and Monitoring

Ichthyoplankton are commonly studied in marine biology and fisheries science. Surveys of ichthyoplankton populations can provide valuable information about fish stocks and marine productivity. They can also be used to monitor the effects of climate change and other environmental factors on marine ecosystems.

See Also

• Plankton
• Fisheries science
• Marine biology
• Marine ecosystem