376 Part III. — Ttrentidh Annual Report 



average length of 229*2 mm., or 9 inches. The limits and averages of 

 these larger groups, as already indicated, are uncertain. 



II. Off Aberdeen. 



A series of hauls were made, from eight to twelve miles off Aberdeen, 

 where a depression in the bottom exists, the depths varying from about 50 

 to 70 fathoms. The number of long rough dabs obtained varied very 

 considerably. The results of their measurement formed a great 

 contrast to those described above, the curves being usually extremely 

 irregular or erratic. In some cases a series was represented only by 

 the larger or by the smaller individuals belonging to it ; in other cases 

 the greater number appeared to belong partly to one group and partly 

 to another. After plotting the measurements in "S-centimetre groups, 

 in 2-millimetre groups, and in 1-centimetre groups, discordant results 

 were in many cases obtained. There are indications that the differentia- 

 tion of the sexes was sometimes not exact, particularly in June, July, and 

 August, but that this does not explain the circumstance referred to is 

 evident from the curves of thehaul in December (PI. XVII), when the 

 sexes were carefully separated, all those not clearly females being opened. 

 The proximity of the shallower water in and near Aberdeen Bay, where 

 long rough dabs are also found, may perhaps partly explain the diffei'ence 

 of the results from those obtained far from shore, since the temperature, 

 and no doubt the feeding, vary within a short space, whereas in the 

 deep water in the open sea the conditions are more uniform. 



The first series of younger fishes was not represented in the hauls in 

 June and July, but they were found in the haul on 21st August. 

 Eleven were then captursd ranging in size from 48 to 57 mm., and 

 having an average length of 53'0 mm., or 2i inches. In September two 

 were obtained measuring 54 and 58 mm. On 5th November two females, 

 63 and 67 mm., and four males from 60 to 64 mm., were taken, the 

 average size being 65'0 mm. for the former and 62'0 mm. for the latter, 

 and the mean was 63'0. On 28th November the number caught was 

 eleven, ranging from 61 to 75 mm., and having an average length of 

 66 "1 mm. On 16th December 116 were caught varying in size from 53 

 to 80 mm., the average size being 65*5 mm., and in January none were 

 taken. So far as these observations go they shoAv a growth of 10 mm. in 

 the period from 21st August to 5th November, and of 2*5 mm. between 

 5th November and 16th December. 



Tlie next sei-ies, as already mentioned, was imperfectly and irregularly 

 represented in the hauls. On 28th June nineteen females from 78 to 

 113 mm. were fairly well defined; they had an average length of 

 97.5 mm., or 3y^^ inches. Eleven males belonged to the same group, from 

 90 to 117 mm., and with an average size of 103'4 mm. On 28th 

 November the same series comprised eighteen females from 110 to 

 142 mm., the average size being 125*6 mm., or 4-|-f inches, and eleven 

 males ranging from 107 to 135 mm., and averaging 123"6 mm. The 

 apparent increase in length in the five months was thus 28" 1 mm. for the 

 females and 20*2 mm. for the males, while the apparent annual increase 

 from the preceding series was 58*7 mm. The next series was fairly well 

 defined in this haul, the females numbering 22, ranging from 150 to 

 196 mm., and averaging 175-9 mm., or 6||^ inches; and the twenty-six 

 males varying from 141 to 174 mm., and having an average size of 

 165"4 mm., or 6i inches. Comparison with the previous group shows 

 an apparent annual rate of growth of 50*3 mm. ( 2 inches) for the 

 females and of 31 '8 mm. (1| inches) for the males. 



The haul on 16th December proved the most productive, 1823 long 



