SEA-FISHERIES LABORATORY. 289 



23,000 to 2,000 — may perhaps be some indication of the 

 rate of destruction. 



If we look next at the Copepoda record for Stat. 

 III., outside the Bay and along the shore to the North, 

 during the period from the end of March to the beginning 

 of July, we find that between March 30th and April 5th 

 nearly all the commoner species of Copepoda increased, 

 but the most marked abundance was that of Oithona 

 (over 8,000). During the second week in April numbers 

 were low, then about April 13th to 25th a more general 

 increase set in : first Acartia became more abundant 

 (1,600), then P seudocalanus (2,600), and then Oithona 

 (over 5,000) again. Numbers were low during the greater 

 part of May, till the 21st, when Oithona again rose (2,750), 

 and again (3,800) on June 7th and June 25th (3,530). 

 Finally in August this species reached its maximum of 

 over 20,000. Acartia is most abundant at beginning of 

 June (9,880), and again on June 19th (7,980) and on 

 August 3rd (3,900). From this it is seen that the increase 

 of Copepoda in spring outside the Bay is mainly due to 

 Oithona, in June to Acartia, and in August to Oithona 

 again. P seudocalanus does not rise to any great maxima, 

 but relatively to the other Copepoda is more generally in 

 evidence in April than in summer. 



It would be more satisfactory if we could be certain 

 in every case as to which adult species the Nauplii and 

 juveniles became. In some of the more important rases 

 they have been determined. The Nauplii at Stat. I. on 

 April 6th, 7th, and March 31st, and at Stat. III. on April 

 2nd, 16th, and 17th, are mainly P seudocalanus, with 

 smaller numbers of Temova, Acartia and Oithona', these 

 three latter were not very plentiful, and the names are 

 placed in the order of their relative abundance. Most of 

 the 8,000 " juvenile " Copepoda on April 13th appear to be 

 early stages of Acartia. 



