168 
BULLETIN OF THE BUREAU OF FISHERIES 
the spring less than a mile from the collecting station increased the surface catch 
somewhat. It is barely possible that all early specimens taken may have originated 
from that source. Their absence in records of past years, combined with their 
total absence during the early spring of 1924 (when no larval cod were liberated at 
Woods Hole), seems to substantiate this possibility. It must be remembered, 
however, that the unusually warm weather existing during the early part of the 
past winter apparently prevented the adult fish from spawning on their usual 
grounds, and for that reason no eggs were available at the hatchery. The cod 
may have sought deep areas so far from the coast that the early forms, which were 
never abundant in this region anyway, could not be transported into these waters. 
Fishermen reported that they had never known the cod catch to be so small on the 
southern New England grounds as during the early winter of 1923. They were 
totally unable to supply the Woods Hole station with any spawning fish. The 
usual fall school which annually enters Narragansett Bay also failed to appear. 
It will be interesting to learn whether the postlarvas appear as usual in May, 1924. 
In Figure 67 and Table 5 several fish taken rarely in past years are listed. 
Most of these are southern forms and occur only in the summer when the Gulf 
Stream inhabitants are blown in. LactopJirys trigonus, Cryptacanthodes maculatus 
Anarhichas lupus, and Seriola zonata are representatives of this fauna. 
Table 5. — Fishes very rarely taken in surface collections 
Leptocephalus conger 
Osmenis mordax 
Poronotus triaeanthus 
Lactophrys trigonus. 
Cyciopterus lumpus 
Cryptacanthodes maculatus 
Anarhictias lupus ._ 
Rhinonemus cimbrius. 
Lophius piscatorius 
Pseudopleuronectes americanus 
Limanda ferruginea?-. 
Seriola zonata. 
Pomolobus pseud oharengus 
Jan. 13, 1903 _ 
Feb. 28, 1895; July 14 and 15, 1896; and June 19, 1899... 
Aug. 9 and 10, 1898 _ 
Sept. 26, 1893 
June 20, 1898; June 5, 1905; and June 18, 1907.- 
Apr. 22, 23, 25, and 26, 1907 _ _ 
May 1 and 2, 1899, and June 3 and 6, 1899 _ 
Apr. 1, 27, 28, and 30, 1900; June 2, 3, 4, 5, and 6, 1906; and July 17, 1900 
June 10, 1899- 
Apr. 13, 1897_ 
Jan. 4, 1908- 
Aug. 30, 1907 
July 13, 1896 
One. 
Many. 
Few. 
Many. 
Do. 
Do. 
Few. 
Very many. 
Few. 
Many. 
One. 
Few. 
Do. 
The remaining figures show clearly that the fish have a definite breeding 
season within certain limits, usually determined by temperature. Temperature chart 
for the spring of 1923 (fig. 5, opp. p. 100) indicates how unusually cold the water 
was. Tlie result was that many of the fish, as well as other larval forms, did jiot 
appear. The approximate temperature throughout the breeding season of each 
common species may be found by comparing the individual figures with Figures 
4, 5, and 6. This particular temperature, however, must not be regarded as the 
complete governing factor. At some time earlier in the year a rise or fall in tempera- 
ture caused the ovaries and testes to ripen. When the sex products have com- 
pletely matured they will be extruded within certain limits irrespective of tempera- 
ture. After this extrusion the immediate temperature then plays its part. Cod 
eggs have been made to hatch in 9 days or 64 days by varying the temperature of 
the water. 
