SEA-FISHERIES LABORATORY. 115 



present. The larval decapods observed in June were again 

 numerous, and the Trachelifer stage of Jaxea was not un- 

 common. The pelagic worms Sagitta and Tomopteris were 

 frequently noticed amongst the stomach contents. A few 

 medusoids were observed and one young Sepiola. Several 

 stomachs contained young rockling which had their stomachs 

 filled with Temora. No Oikopleura were noticed. The last 

 sample of mackerel was examined on September 8th, and very 

 few of the fish had food in their stomachs. One contained two 

 sand eels 12 cms. in length. Another contained digested fish 

 which were probably sand eels also. It is quite evident that 

 mackerel feed on the plankton around them, and make little 

 or no attempt to select the organisms. The abundance of the 

 fish and duration of their visit to any area will be influenced 

 considerably by the richness of the plankton. 



EXPLANATION OF PLATE. 



Fig. 1. Nearly pure Temora catch from the stomach of a 

 Mackerel. A few specimens of Isias were present, 

 and one is shown in the photograph. 



Fig. 2. Plankton consisting of Pleurobrachia and Beroe. 



Fig. 3. Larval Decapods from the stomachs of Mackerel. 



[From photographs by A. Scott.] 



