_ 37 — APPENDIX E: HEINOKE 



open sea — is a kind of true commensalism or not, and of what kind, is not yet known. 

 It is certain, tliat we have practically, never taken the pelagic whiting in our surface net 

 without also taking the jelly-tish, and usually, the more whiting there were the larger was 

 the number of jelly-fish. For the rest, we are unable as yet to say definitely, from lack 

 of definite observations, how far the young fish of other gadoid species, e. g. young had- 

 dock and cod, also live together with jelly-fish; wa may only mention, that all our 

 pelagic young-fish hauls contained jelly-fish, and that haddock and cod, if 

 they occurred in such hauls, were always found together with whiting, and the latter was 

 in the majority almost with exception. 



When the young whiting of the 0-group descend to the bottom of the sea, they also 

 succeed in getting to the coast very quickly and even tolerably far into the mouths of 

 rivers. We have, for example, found them in quantities, from 55 m. in length and more 

 on the sands of the Elbe estuary along with young plaice, in July and August, and once 

 together with cod as far as the opening of the IS'orth Sea — Baltic canal. They penetrate 

 also into the "Wattenmeer" and in autumn are in very great quantities, in length 

 from 6 to 15 cm., both here and on the entire coast of the southern North Sea; at this 

 time, they already mix with the I-group and with small plaice and cod. Many hundreds 

 may be taken here with one haul of the narrow-meshed ground net. Small shrimps 

 (Crangon) form part of the chief food for the young. Beyond the rocky ground at Heli- 

 goland also , we have found young whiting of the 0- and I-groups in great quantities 

 in autumn. 



From lack of sufficient and suitable investigations we are unable as yet to say, how 

 large the whiting is on an average at the end of its first year, and how large the various 

 older stages (I-group etc.) are. We have observed in our aquarium, however, that the whiting 

 grows relatively very quickly in its first year. A young and well-fed whiting, for example, 

 grew from 60 to 115 mm. in length from the 30*^ of July to the 19"' of September i.e. 

 in 50 days, therefore on an average 1-1 mm. daily. In the middle of November, whiting 

 of the 0-group reared in our aquarium measured up to 14 cm. in length. 



With regard to the occurrence and distribution of the older stages of the whiting 

 (from the second year onwards), it appears from all our observations, that they are 

 distributed like the 0-group over the entire region investigated, and the age-groups show 

 no separation in place or time. We have taken whiting of all sizes and stages, 

 beside one another, both beyond the 100 m. line in depths of 100 to 200 m. and in 

 close proximity to Heligoland and the German coast, and usually in no less quantities in 

 the depths of the northern North Sea than in the shallow parts of the southern. 



We have not yet closely investigated the size and age at which the whiting are ripe 

 for the first time. Whiting with running spawn have often been taken at various 

 places in the region under our survey, from March to June; in great quantities at Heligo- 

 land from March to May at sizes from 18 to 49 cm. As spawning whiting have already 

 been observed at a length of 20cm. and less, we may conclude with tolerable certainty, 

 that the maturity of this gadoid begins earlier than with the cod and haddock, probably at 

 the end of the third year, perhaps exceptionally and in the smaller males even earlier. 



The biological picture we get of the whiting, agrees in general with 

 that of the dab and cod. Like these two species the whiting is a stationary 

 fish, whose eggs, larvœ and fully-formed individuals of all ages occur everywhere at the 



