103 



NOTES ON THE AGE AND GROWTH OF FISH. 



By B. STORROW. 



BALLAN WRASSE, Labnis hergylta. 



In the report for the year ending June 30th, 1916, an account 

 was given of a young ballan ^Tasse which came from a rock pool 

 at Cullercoats, and was kept in the Laboratory tanks. The fish 

 w^as from two to three centimetres in length when captured in 

 August, 1915. A size of eight centimetres was attained by 17th 

 Januarj^, 1916, and the scales of the fish, photographs of which 

 were given in the report for 1916, showed two summer gro^\i;hs, 

 with a stoppage of growth between. More scales were taken 

 from the fish on 24th May, 1916, when the length was still eight 

 centimetres, and the scales gave no indication of growth having 

 begun for the summer of that year. 



The accompanying photographs show the scales taken from 

 this fish on 10th August, 1916, and 20th August, 1917, the length 

 of the fish being 8-9 and 12-2 cm. respectively. The winters inter- 

 vening between the summer gTowths are clearly marked, and the 

 scales gave a reading which coincides with the kno^Ti age of the 

 fish. 



It will be observed that the growth made for the third summer 

 was small compared ^\ith those of the second and fourth summers. 

 During this period the laboratory attendant frequently reported 

 that the fish was not feeding as it had done, and attempts were 

 made by introducing mysids and amphipods into the tank to 

 provide conditions somewhat similar to those found in the sea 

 near low water, but no improvement in feeding was observed. 



Three scales were taken from the fish on 10th August, 1916, 

 and these when expressed in terms of the length of the fish give 

 the following average growth : — 



Winters. 

 Length. First. Second. 



8-9 ... 3-6 ... 7-8 



