of the Fishery Board for Scotland. 



137 



Cod prom Aberdeen, caught October 1900. 



Length of fish 8'6cm. (3| inches). Length of scale from side of body 

 •94mm., breadth *46mm. Number of concentric lines on scale 10 or 11. 

 No winter zone. Age six or seven months. 



Specimens of Cod from Aberdeen, caught November 10, 1904. 



Of the following four specimens only parts of the skin and pectoral 

 girdle were examined, so that only the scales give indications of age. 



(1) Length of fish Jfl'Ocm. (/ ft. 0} t in), $, immature. — Length of 

 scale 2 , 4mm. Two winter zones distinguished Within the first winter 

 zone 9 or 10 rings, from first to second 19 or 20, outside the second 

 6 or 7. Age inferred two years and about six months. The rings 

 in this and other cases are counted on the posterior part of the scale, as 

 they do not all seem to extend round the whole scale. 



(-) Length of fish 5J/.cm. (J ft. -9| in.), <$, immature. — Number of 

 lines in first annual zone 9 or 10, in second 13, in third 10, beyond 9. 

 Probable age three years six months. I was not quite certain in this 

 case about the number of winter zones in the outer part of the scale ; the 

 total number of complete annual zones may have been two or three, but 

 three seemed more probable. 



(3) Length offish GJ+cm. (2 ft. lMn.), $, immature. — First zone 10 lines, 

 second 12 to 14 lines, third 12 lines, outside 8 or 9. Some doubt as in 

 previous specimens. Age of fish three years six months, or possibly two 

 years six months. 



(4) Length of fish 73cm. (2 ft. 5± in.). — d with large testes but not 

 ripe, probably mature. First zone 10 lines, second 12 to 15, third 12 to 

 15, beyond 4 or 5. Probable age three years six months. 



Specimens of Cod caught at Aberdeen about March 9. 



(1) Length of fish 2J + '3cm. (10 in.). — Otolith shows two annual 

 zones. Scale also shows two zones; number of rings in first 13 or 14. 

 Age inferred two years. 



(2) Length of fish 30'Scm. {12\ in.). — Both scales and otolith indicate 

 two annual zones. Inferred age two years. 



(3) Length of fish 30'7cm. {12\ in.). — In the scales a single winter 

 boundary zone is quite evident. It is also evident that the ridges are 

 close together at the edge of the scale, showing that the winter growth 

 was nearly or quite finished when the fish w r as killed. Inferred age two 

 years. A transverse section of the otolith also showed two annual zones 

 (pi. viii., fig. 16). 



(ft) Length of fish 33'5cm. {13\ in.). — In scales one complete annual 

 zone and another outside it. It seemed as if the two or three outermost 

 rings belonged to the commencement of the new summer's growth, but I 

 was not sure of this. Number of rings in first annual zone 14-15, in 

 second 16, beyond 3. Transverse section of otolith also showed two 

 complete annual zones. Both in scales and otoliths a slight interruption 

 was visible in the first summer's growth, but this did not seem to be a 

 definite winter zone. Such an interruption might occur probably enough 

 occasionally from unfavourable conditions. Age inferred two years. 



The following specimens of cod were obtained at the same time, and 

 the heads were sent to me, with labels indicating the size and condition 

 of the fish : — 



(1) Length of fish JfJfScm. (i7| in.), l^lbs. weight.— $ with small 

 ovary, probably immature. Otolith in transverse sectio shows three 

 annual zones. Inferred age three years. 



