Lantern fish (Benthosema pterotum) resources as a target for commercial exploitation in the Oman Sea

The skinnycheek lantern fish Benthosema pterotum (Myctophidae) represents a virgin resource in the Oman Sea. Because of its potential importance for fishmeal production there has been great interest during the last decade in starting commercial exploitation. Acoustic surveys to estimate stock biomass and trial fishing using pelagic trawls were carried out in Iranian waters of the Oman Sea from 1992 to 1998. Lantern fish schools are found in offshore waters, on the edge of the continental shelf wherever sea depth is more than 100 m. During the day the fish occur in two vertical layers, with the densest schools in the shallower layer (80-130 m), whereas at night B. pterotum occur in a single dispersed layer closer to the surface (mainly at 30-70 m). Biomass estimates range from 1 to 4 million tonnes (t), with an average of 2.3 million t. Densities vary seasonally, with the highest densities recorded in spring (May-June) and lowest in autumn (October-November). The highest densities were seen in the western Oman Sea. Although recommendations can be made with regard to the best fishing seasons, areas and depths, trial catch rates were too low (< 30 t daily per boat) to support a commercially viable fishery. Further trials are needed to identify the best gear and vessel size.