— 21 — APPENDIX E: HEINCKE 



represented only the cod, or only the haddock, or both species. The occurrence of larvae of 

 both species can always to some extent be settled with certainty. A confusion of the larvae 

 of the cod with that of the saithe fGadus virensj, which might easily occur, will scarcely 

 come into consideration in the present work, as the saithe plays no great part, probably, 

 in the region investigated in March. 



In March 1903, altogether 3750 eggs of these two species were taken in the vertical 

 hauls; amongst these, there were only 114 with certain haddock-embryos and about twice 

 as many with certain cod-embryos. Of the larvae taken with these eggs, 65 in all were 

 those of the haddock and 534 those of the cod. 



From this, the following is clear. As the spawning time of both species, to our 

 knowledge, is essentially the same (January to May), many more haddock larvae should be 

 taken than in the case in reality, when we consider the relative numbers of the cod and 

 haddock in the North Sea, namely, that the haddock is relatively much more abundant 

 than the cod. We may conclude with certainty therefore, that our March cruises have not, 

 in the main, lit upon the principal spawning grounds of the haddock so much as those of 

 the cod. From observations made in previous years, it appears, that very great masses of 

 haddock eggs occur about the middle of March in the open North Sea to the north of the 

 Great Fisher Bank, between 59° and 60° N. L. On the other hand , we have never found 

 spawning haddock in the southern North Sea, though spawning cod have been taken; 

 consequently, cod eggs aud larvae are certainly to be expected here principally, if not 

 almost exclusively. 



Haddock. 



In the neighbourhood of the land, as far as to the 40 m. line, unmistake- 

 able haddock eggs and larvae were taken during our seasonal cruises either 

 not at all, as in the southern part^ of the North Sea, or only in very small 

 quantities, as in the neighbourhood of Horns Reef and at the Skaw. In the 

 south eastern parts of the North Sea, haddock eggs become somewhat more common to- 

 wards the centre between the 40 m. line and the south edge of the Dogger, and increase 

 further in numbers in the neighbourhood of the latter. On the Dogger Bank and beyond 

 its northern edge, they were often just as numerous as those of the cod, taken at the 

 same time. Haddock eggs were also found in the few hauls made on the Little Fisher 

 Bank. On the Great Fisher Bank, the number of the well-developed, certain haddock 

 eggs amounted to about three times those of the cod, in a total quantity of 300 eggs of 

 both species per square meter. 



Cod. 



Cod eggs and larvae were taken in March at all the regions investi- 

 gated, almost without exception, from the 70 ro. line in towards the land they 

 were distinctly scarcer and were sometimes quite absent. Cfreater abundance of eggs, to 

 over 100 to 450 eggs and larvae per square meter, occurred N.W. from Heligoland within 

 and beyond the 40 m. line in the centre of the southern corner of the Dogger (Clay Deep), 

 further, on the north corner of the Dogger and the centre of the Great Fisher Bank. 

 Contrary to expectations, few cod eggs were found on the Jutland Bank and at Horns Reef 

 (10 to 30 per square meter); they only increased to the west of this in the neighbour- 



' In the Heligoland plankton, we have previously taken but few isolated haddock eggs — 

 1 — 2 yearly. 



