We recently found this video while evaluating the influence of marine forage fish abundance on recent salmon and steelhead stock fluctuations along the west coast.
Baitfish, or forage fish as they are called by fisheries managers, are the middlemen of the marine environment, turning plant and animal matter (phytoplankton and zooplankton) into energy for larger predatory species of seabirds, marine mammals, and large fishes. Examples of forage fish species include herring, smelt, anchovies and sardines, and most sustain both commercial and recreational fisheries.
Forage fish populations tend to fluctuate greatly due to natural factors such as changes in environmental conditions and reproductive success. Forage fish join large schools as juveniles and spend their entire lives in these tightly packed formations. Their abundance tends to fluctuate greatly from year to year, and the fate of commercial and recreational fisheries hinges on their health.
Video source: ProFish-n-Sea Charters.