Student Stuff
Gill rakers
Gill rakers are bony or cartilaginous projections which point forward and inward from the gill arches. They aid in the fish's feeding. Their shape and number are a good indication of the diet of the fish. Fishes which eat large prey such as other fishes and molluscs have short, widely spaced gill rakers. This type of gill raker prevents the prey item from escaping between the gills. The gill rakers of the Blue Mackerel are like this.
Fishes which eat smaller prey have longer, thinner and more numerous gill rakers. Species which feed on plankton and other tiny suspended matter have the longest, thinnest and most numerous gill rakers, with some species having over 150 on the lower arch alone.
Further reading
- Helfman G.S., Collette, B.B. & D.E. Facey. 1997. The Diversity of Fishes. Blackwell Science. Pp. 528.
- Michael, S.W. 1998. Reef Fishes. Volume 1. A Guide to Their Identification, Behaviour, and Captive Care. Microcosm. Pp. 624.
