MARINE BIOLOGICAL STATION AT PORT ERIN. 45 



collected during May contained 28,680 Noctiluca. This 

 represents the maximum, and it is considerably earlier than 

 has been our experience of the organism in the Welsh and 

 Lancashire coastal waters. Noctiluca is usually to be found 

 in the plankton of North Wales from July onwards, but it 

 is only in September that we find it to be abundant in Barrow 

 Channel and off Walney Island. Sagitta was present throughout 

 the ten months, but there was no well-defined maximum. 

 The eight May collections gave 868 specimens, nine in June 

 828 and nine in August 847. Fish eggs were also represented 

 in every one of the ten months ; and their maximum occurred 

 in April. 



The pelagic Copepoda arrived at their maximum in 

 September. It was estimated that the eight collections 

 with the coarse and fine nets contained 557,620 specimens, 

 chiefly Paracalanus and Oithona, but Pseudocalanus, Acartia, 

 Calanus, Isias, Temora and Centropages were also represented. 

 Calanus reached its maximum in August, Isias in September 

 when it was quite unusually abundant, Pseudocalanus in June, 

 Paracalanus in September, Temora in April, Centropages in 

 August, Acartia in July, and Oithona in July. Anomalocera 

 made a sudden invasion in April, when the total for nine 

 hauls was 5,500. It rapidly decreased during the next 

 two months, and was not observed after the end of June. 

 The other pelagic species Microcalanus, Candacia, Metridia 

 and Parapontella appeared to make short spasmodic visits 

 into the Bay from time to time. Eight Candacia were found 

 in the January plankton and twenty-two in October. Our 

 experience of Metridia in the Bay collections indicates that 

 it lives below the surface. It is frequently observed in vertical 

 hauls although it is absent from the surface collections taken 

 at the same time. 



A fuller account of the Bay plankton, along with the 

 results of the Easter work at sea carried out on the yacht 

 " Runa," will be published later on in the Lancashire Sea- 

 Fisheries Annual Report. 



