of the Fishery Board for Scotland. 

 Long Rough Dab. 



245 



D<atc. 



Net. 



Phico. 



Number of 

 Specimens- 



Size in mm. 



April 18, 1895 Surface 

 May 7, 1892 lAJ id water 

 „ 11, 1891 



„ 15, 1890 



„ 31, 1892 



„ 2, 1893 

 11, 1893 



„ 11, 1896 



„ 20, 1890 



„ 22, 1892 



„ 25,1895 



„ 26, 1892 



„ 27, 1892 



28, 1895 ! 

 June 1, 1888 

 „ 9, 1892 i 



„ 10, 1892 



„ 13, 1892 



„ 13, 1888 



„ 15, 1892 



„ 22, 1893 



23, 1893 

 „ 24, 1895 



Bottom 



Midwater 



Bottom 



Station IT., Forth, 



7 miles S.S.K. of Bell Rock, 

 4 miles E. of May Island, 10 



fathoms. 

 Station VIII., Forth, 

 Cross-section III., Forth, ... 

 Station IV. , Moray Firth, . . . 

 Station VI., Smith Bank, ... 



St. Andrews, 



Station III., Aberdeen, 



N.W. of Aberdeen, 



Station VIT., Forth, 

 Between Liston Bank and 



May Island, 

 Cross-section II., North half. 



Forth, 

 Station VIII., Forth, 



St. Andrews, 



Stations VIII. and IX., 



Forth, 



Stations I. and II., Forth,.,. 



Station V., Forth, 



St. Andrews, 



Station II., Forth, 



Cross-section II., South half, 

 Forth, 



12-14 miles off Aberdeen, ... 

 St. Andrews, 



1 



y 0 



9 



7 to 13 



3 



4 to 10 



11 



10 to 21 



5 



11 to 14 



1 



g 



3 



8 to 11 



5 



4 to 11 



4 



10 to 12 



5 



lO to 14 



2 



5, 9 



13 



8 to 11 



4 



5 to:i4 



2 



7, 8 



6 



11 to 12 



8 



9 to 21 



6 



12 to 17 



3 



6 to 13 



3 



8 to 9 



0 



9 to 20 





u 



\ 



18 





8, 12 



Dr. Fulton gives the spawning period of the long rough dab as from 

 the end of January to middle of May. The collections fairly well 

 correspond with this. There are no specimens during March and the 

 first part of April, and no specimens after the 24th of June. • The latter 

 fact is remarkable. The largest specimens, with metamorphosis barely 

 half complete, were 21mm. long. Specimens from that size onwards are 

 absent. The conclusion seems to be that they .disappear from the inshore 

 water, migrating seawards. 



Whether they migrate by instinct or are drifted by currents may be 

 disputed. If drifted by currents, then there must be undercurrents 

 tending from the shore out to the sea. Only one specimen was obtained 

 on the surface far up the Forth ; all the others were from midwater and 

 bottom. Professor M'Intosh, on the Trawling Commission, found the 

 young long rough dabs, from \\ to inches, in company with the dab on 

 the ground 15 miles off St. Abb's Head; also off St. Andrews Bay and 

 Aberdeen Bay. The long rough dab, therefore, corresponds closely to the 

 off-shore specimens of the dab. It does not appear to frequent the 

 inshore waters. 



The data are too few to give any accurate notion of the rate of growth ; 

 but, if the specimens from Station VIII., Forth, on loth May, be 

 considered, the largest, 21mm., can be chosen to representthe earliest 

 hatched. Taking 18 days as the period of incubation during February — 

 it is 16 days during March (Fulton) and a similar period for the larval 

 stage (M'Intosh) — and calculating from the 1st of February, this specimen 

 has taken a little over two months during the early post-larval stages 

 alone. Possibly another four weeks might be required to complete 

 metamorphosis, though it may be very rapid during its later stages. 



