SEA-FISHERIES LABORATORY. 99 



was started at the shipyard. This is generally attributed to 

 the escape of acids from the battery tanks. Dead conger- eels 

 and other fishes have been seen occasionally floating about in 

 the vicinity of the fitting-out berths. The fishery for sea-fish 

 in the channel is carried on throughout the year, but the results 

 are very variable. The fishermen suggest various reasons for 

 this such as too much steamer traffic, too much dredging, and so 

 on. It is quite certain that the success of the plaice-fishery 

 at any rate depends largely on the abundance of young mussels 

 up to half an inch in length on the beds. As soon as the supply 

 is consumed the fish leave the area. The repopulation of the 

 beds is going on every year, but accidents occur, such as 

 sanding up and washing away by storms and tides, and a 

 fishery for plaice may only occur at irregular intervals. The 

 permanent bottom fauna, which can be seen very well at low- 

 water of a spring tide, has undergone no diminution. The 

 plankton of the channel corresponds with what is found offshore 

 and varies with the seasons. Fish eggs and larvae are fre- 

 quently found in the spring samples. 



In 1919 and 1920 complaints were received from the stake- 

 net fishermen at Eoosebeck that large quantities of thick oil 

 refuse were coming ashore and filling the tails of the nets as 

 the tide receded. Numbers of sea-birds were washing ashore 

 in a dead and dying condition. The matter was gone into and 

 the fishermen's reports were found to be correct. The receding 

 tide for days at a time left the shores coated with oil, which 

 made everything very slippery. Quantities of thick, black 

 oily matter of a somewhat spongy consistency were also 

 washing up, and in this were immersed dead and dying black 

 ducks and divers. A point that was noted and also corrobo- 

 rated by the fishermen was the complete absence of dead or 

 sickly fish, and the shell-fish, mussels, periwinkles, etc., were 

 not being affected. It seemed to be quite clear that the oily 

 matter, although it was apparently destroying the sea-birds, 



