21 



during the whole of thoir early development (see section on "Pelagic youug of 

 species with demersal eggs"). They are therefore but little exposed to the danger 

 of beicg carried away by currents and are extremely commou everywhere iu 

 Dauisli waters wherever the conditions are favourable to theh- oecurrence. 



The case is (juite different for the yoiing of those species with demersal 

 eggs whicli have a true pelagic stage. In this stage they corae under tlie influence 

 of the currents, and the result is that their bottom- stages are seldom found in the 

 waters within the Skaw. We have thus only occasionally found the bottom-stages of 

 the common and long-spined sea-scorpions (Cotkis scorpius and huhalis), pogge (Agonus 

 cafaphradus), gunnel (Centronntus gunellus), liparids (Liparis sp.) and sand-eels (Am- 

 modi/fes sp>.), the last on sandy and shallow water, the others on algæ-covered, ofteu 

 stony bottom )iear the coasts. 



The nietamorphosed young of Clnpea are often met witli in extremely 

 great uumbers on the North Sea coasts of Jutland, in tlie uorthern Kattegat aud 

 in the Lim Fjord. In our inner waters they are but few in numbers. 



The bottom-stages of Lumpenus (Lumpenus lampetriformis) keep to soft 

 bottom in deep water (ea. 20 fathoms or more). We have found them in very 

 great numbers iu the western part of the Western Bal tic, from which the currents 

 do not carry away the pelagic young (see p. 63), and where the bottom-stages have 

 specially good conditions for their oecurrence. Elsewhere we liave taken the bottom- 

 stages of Lumpenus in numbers in the true Baltic aud in single specimens at 

 deeper piaces in the Kattegat. 



With regard to the young of the gobies I can give but httle information 

 owing to the defective determination of the species. It appears as if the young 

 and adults of Aphya peUucida and Crystallogohms nilssonii can live pelagically, as 

 we obtain both in intermediate hauls. 



It way be given as a rule, that the hottom-stages are few in numbers in 

 Danish tvaters within the Slcaw. (Tiiis will be shown in more detail iu the special 

 part.) If we have therefore a relatively rich stock of fish iu our imier waters, 

 eveu of the species the bottom-stages of which are wanting or occur there seldom, 

 this is due to the faet that tliese, as soon as the bottom-stage is reached, begin 

 to wander into the waters from which the currents have carried them during 

 development. 



Cont'ludiiig Remarks. 



The features of the distribution of the pelagic eggs and young fishes in 

 Danish waters will be most easily understood if we compare them with the distri- 

 bution in more open waters, where the hj'drographical conditions are not so com- 

 phcated. Before describing the oecurrence of the eggs aud larvæ of the separate 

 species, I shall therefore refer to the extremely clear picture which Jobs. Schmidt 

 has given of the distribution of the pelagic eggs and youug of fishes on the coasts 

 of Iceland; see "Fiskeriundersøgelser ved Islaud og Færøerne i Sommeren 1903". 

 (Skrifter udg. af Komm. for Havunders. Nr. 1, 1904.) 





