User:NBezzina/Clupeidae

Feeding Physiology
The Clupeidae family primarily feed on small planktonic organisms. The teeth of members of this family are either reduced or absent, reduced teeth are miniature teeth that would be barely visible and line the interior of the fish's mouth. The structure of these teeth indicate that these organisms do not need to cut or tear their prey items as they would need fully formed teeth to complete this process. They do, however, possess long gill raker s that are designed for sifting plankton and nutrients out of the water as it passes through their gills. Gill rakers are protrusions on the back side of the gills that help aquatic organisms to trap food particles.

In many Clupeidae, their diet primarily consists of phytoplankton and plant matter during their juvenile larval stages. As the fish mature this diet begins to shift towards larger and more substantive organisms, including more zooplankton and copepod s. This change in diet in possible due to their increase in body and gill raker size, which allows them to capture and process larger organisms to support themselves. Small organisms like these do not need to be ground or torn apart for consumption so pronounced teeth would not serve a purpose in the feeding habits of Clupeidae, instead the use of filter feeding allows for much more efficient nutrient collection.

The fusiform body shape of Clupeidae is also advantageous to their trophic ecology. The tapering body form is a highly aerodynamic form that allows for quick increases in speed and a high maximum speed. Moving at high speeds allows the members of this family to regulate their feeding habits and avoid predators. Clupeidae can moderate the speed at which they swim to increase their uptake of nutrients. As with all filter feeders, Clupeidae cannot take in food if nutrient rich water does not pass over their gills. To moderate this, members of this family have been found to increase their swimming speed when they sense that there is a high concentration of food items in order to take advantage of this feeding period. Keeping a high swimming speed during periods of low food availability would not be efficient to maintain over long periods of time as the organisms would not net as much energy as they may need to in order to sustain themselves and increase their fitness. Increasing their swimming speed during feeding periods would allow them to take in more plankton while not suffering consequences from maintaining that speed.