<P> Herrings often hunt copepods . If they encounter copepods schooling in high concentrations, the herrings switch to ram feeding . They swim with their mouth wide open and their opercula fully expanded . Every several feet, they close and clean their gill rakers for a few milliseconds (filter feeding). The fish all open their mouths and opercula wide at the same time (the red gills are visible in the photo below--click to enlarge). The fish swim in a grid where the distance between them is the same as the jump length of the copepods . </P> <P> Baleen whales feed on plankton by a technique called lunge feeding . Lunge feeding could be regarded as a kind of inverted suction feeding, during which a whale takes a huge gulp of water, which is then filtered through the baleens . Biomechanically this is a unique and extreme feeding method, for which the animal at first must accelerate to gain enough momentum to fold its elastic throat (buccal cavity) around the volume of water to be swallowed . Subsequently, the water flows back through the baleens keeping back the food particles . The highly elastic and muscular buccal rills are a specialized adaptation to this feeding mode . </P> <Ul> <Li> <P> Herring ram feeding on a school of copepods </P> </Li> <Li> <P> School of adult Indian mackerel ram feeding on macroplankton </P> </Li> </Ul> <Li> <P> Herring ram feeding on a school of copepods </P> </Li>

What are the different modes of feeding found in fishes