194 



Part 111. — Fifteenth Annual Beport 



IV. — CONTRIBUTIONS TO THE LIFE-HISTORIES AND DE- 

 VELOPMENT OF THE FOOD AND OTHER FISHES. By 

 Professor M'Intosh, Gatty Marine Laboratory, University of St 

 Andrews. (Plates V., VI., and VII.) 



CONTENTS. 



PAGE 



1 On the Life-Histories of the Cod, the Haddock, and the Whiting, . 194 



2. On a very young stage of a form resembling the Horse-mackerel (Caranx 



trachurus, L. ), . . . . . . . . 205 



3. On the Post-Larval and young stages of the Five-bearded Rockling {Onos 



mustela, L.), 0 . . . . ■ . . 206 



4. On the very young stages of the Tadpole Fish (Raniceps raninus, L. ), . 209 



1. The Life-Histories of the Cod, the Haddock, 

 and the Whiting. 



The Cod. 



The history of the early stages of the cod in Scottish waters has, 

 within recent years, been more or less elucidated, so that the remarks 

 on this form will be comparatively brief. The chief spawning- 

 grounds are in the offshore waters, such as east and south-east 

 of the Isle of May, and the deep water off Montrose and Aberdeen, 

 Smith Bank in the Moray Firth, and similar areas. The eggs are 

 often wafted inshore, as also are the larvse, which are distinguished by 

 their speckled appearance, due to the presence of five blackish pigment- 

 bars. The greater number of the larvae, however, attain the post- 

 larval stage in the offshore water, and only seek the more varied life 

 of the inshore when they reach the length of J to f of an inch, and 

 have descended considerably in the water. They lose the speckled 

 aspect of the larvse, and the black pigment is aggregated dorsally 

 and ventrally, so that their appearance is much altered at J an inch. 

 Yet a further change occurs after they are a little older, and when they 

 approach the tidal region at the end of May or beginning of June. 

 The black pigment, which had been confined to the dorsal and the ventral 

 borders, and to the median streak, now (as the fishes reach the length 

 of an inch, or a little more) forms vertical or zig-zag bands connecting 

 the former along the sides. 



During June and July they frequent the shallow rock -pools, both 

 of open bays and estuaries, at ebb-tide in company with the green 

 cod, from which, as I have formerly shown, they are readily dis- 

 tinguished by the reddish hue of the head, and the beautifully 

 variegated body, which, upon a pale greenish ground, is dotted 

 all over with black pigment - specks, while larger ones occur 

 over the brain, and on each side along the dorsum (PI. YI. fig. 5). 

 The first two dorsals are also dotted with black pigment, enlivened with 

 touches of opalescent bluish, touches of the same hue occurring at 

 intervals along the middle line of the dorsum when viewed from above, 

 one of the brightest being between the second and the third dorsal. The 

 pale patches between the dark bars have a beautiful pearly lustre. About 

 eight dark blotches are placed along the median line, and as these are flecked 

 by darker patches in the upper lateral region, they give a characteristic 

 appearance to the fish. The upper lateral region (just above the lateral 



