268 



BULLETIN OF THE BUREAU OF FISHERIES 



idea of the length of the season may be obtained from the following table, giving 

 the average number of eggs in cleavage stages per station on the Plymouth grounds : 



Table 4 



Trip 



Date, 1924-25 



Average 

 number 

 of eggs 



Trip 



Date, 1924-25 



Average 

 number 

 of eggs 



1. 



Dec. 3 



26 

 46 

 57 

 24 

 72 

 8 



7 



Feb. 24-25 



71 

 70 

 304 

 167 

 10 



2 



Dec. 9-11 



8 



Mar. 10 



3. 



Dee. 16-17 



11 



Apr. 7-8 



4, 



Dec. 22-23 



12 



Apr. 21 



5 



Jan. 6-8 „ 



13 





6 



Feb. 6-7 







This table shows clearly the increase in production as the spawning season 

 progressed and also the destruction of eggs by the storms that occurred at the time 

 of the fourth and sixth cruises. (See p. 286.) Up to the time of cruise 8, for reasons 

 given on page 274, it is safe to assume that most of these were cod. 



Omitting for the moment the small returns on December 22 and February 6, 

 which obviously represent artificial results (p. 286) and give no indication of the 

 true production that took place at the time, the figures on the Plymouth grounds 

 show that spawning had already begun on November 12, increased through Decem- 

 ber, and reached its height in January, February, and early March, although, as will 

 be shown later, considerable spawning, no doubt, took place throughout April. 

 Taken alone, this table gives no indication of the end of the breeding season at 

 Plymouth, for in late March and early April the great influx of haddock and cod 

 eggs from the east (fig. 8) complicated the results and made it impossible to dis- 

 tinguish locally spawned eggs from the immigrants. 



Extending the area to cover all of Massachusetts Bay and computing the 

 average number of eggs per station, it is seen that the conditions at Plymouth reflect 

 very well the general conditions for the whole bay, as would be expected if that 

 locality forms the source of supply. 



Table 5 



MASSACHUSETTS BAY 



Trip 



Number 

 of stations 



Total 

 number 

 of eggs 



Average 

 number 

 of eggs per 

 station 



Mean 

 surface tem- 

 perature 

 CO 



Mean bot- 

 tom tem- 

 perature 

 (°C.) 



Date 



1 





9 



222 



25 



6.14 



6.13 



Dec. 3. 



2 





15 



445 



30 



6.20 



6. 25 



Dec. 9-11. 



3 





14 



797 



57 



5.02 



5. 46 



Dec. 16-17. 



4 





13 



250 



19 



4.30 



4.75 



Dec. 22-23. 



5 





14 



699 



50 



2.54 



2.60 



Jan. 6-8. 



0 





15 



236 



16 



.75 



.95 



Feb. 6-7. 



7 





7 



1,083 



155 



1. 65 



1.68 



Feb. 24-25. 



8 





6 



305 



61 



2.00 



1.89 



Mar. 10. 



11 





14 



1, 962 



140 



4.59 



3.40 



Apr. 7-8. 



12 





20 



20, 761 



1,038 



5.27 



4.02 



Apr. 21. 



13 





20 



4,642 



239 



8.89 



4.57 



May 20-22. 



IPSWICH BAY 



6 



319 



64 



3.54 



2.50 



8 



940 



117 



3.54 



2.72 



4 



508 



127 



4.61 



2.64 



Mar. 12 

 Mar. 25. 

 Apr. 7. 



