The food and feeding habits of early stages of grey mullets in the Haifa Bay region

Abstract

A study was carried out on the gut contents of mugilids, 4.27–22.88 mm total length, to find their food preferences in the natural environment. This information would aid in the feeding of young grey mullets obtained from induced reproduction. Samples were obtained from monthly cruises to five stations in the Haifa Bay area, located over depths from 5–25 fathoms (8–45 m). Neuston net, vertical and horizontal plankton net hauls were carried out, at each station. Variations of the common organisms in the plankton and the food components found in the digestive tracts of various size-groups of the grey mullets are tabulated. Copepods were found to be the most important food item in the gut contents, at all times of the year and at all sizes of mullets taken in the neuston. It appears that the smaller-sized fish feed on the smaller copepods, while the larger-sized fish feed on a wider range of sizes and species of Copepoda, although size of the prey was not the only factor influencing selection. No relationship was found between the availability in the plankton of the species, of a size that could be swallowed by the young mullets, and their proportion in the gut contents. This indicates that these fish are selective in their feeding in the natural environment. It was found that the preferences change with the size-group of mugilids.