Dakin and Latarche — The Plankton of Lough Neagh. 87 



The following account of the movements of the PoUan is very interesting, 

 but it is only culled from the observations of the fishermen. As remarked 

 above, it seems a subject that is well worth following up. The Pollan 

 spawning season commences towards the end of November, and at this time 

 the fish, curiously enough, migrate to the stony or gravelly bottom quite 

 close to the shore. The eggs are left here, and the fish in January travel 

 outwards to the " muddy " bottom, where they remain for some time. Thus 

 in the spring, when our plankton catches were being taken, the fishing 

 was being worked some distance away from Antrim in water of about 40 feet 

 depth. As the summer comes on, in June, the fish once more migrate inshore 

 and occur in hundreds in water of 6 to 12 feet deep. The summer fishing, 

 therefore, is in this shallow water, within a stone's throw of the bank. 

 During the summer the fish appear to be influenced in some way by 

 meteorological conditions, and it is said that they travel irregularly out and 

 inshore. The fishing certainly varies in this way, as our observations have 

 shown. In autumn the fish pass outwards to the muddy bottom areas, 

 where they remain until the month of November and the breeding-season. 

 Such are the facts that are known to fishermen. So far as our knowledge is 

 concerned they seem to be correct for the Antrim corner of the lake. 



From the figures kindly supplied by the Irish Department of Agriculture 

 and Technical Instruction it will be seen that there is a steady but small 

 decrease in the amount of Pollan captured. The fishermen all agree that the 

 Pollan fishery is becoming worse, and all the evidence that could be gathered 

 at Antrim goes to show that the year 1912 is so far the worst on record. We 

 are of opinion that the fisheries should be carefully looked into. It may be 

 that the blue-green alga increasing in amount has something to do with the 

 decrease. Other causes, however, are certainly at work, and though there 

 are regulations limiting the size of fish to be caught, and rendering the capture 

 of small fish illegal, we are told that this fishery is regularly carried on. 

 Apparently the officers can only investigate fish which are landed for sale. 

 These are of the normal size, and caught with nets of legal mesh. The small 

 Pollan are captured with other nets and are then actually used to bait lines 

 for the eel-fishery. Thus they escape the authorities' notice, and render 

 futile any regulations that may exist. 



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