of the Fishery Board for Scotland. 173 



shrimp-net in the same locality, measuring from 40 to 70mm., but all 

 except four were less than 55mm., these being — one at 56mm., two at 

 65mm., and one at 70mm. From the curves for the whole of the sprats 

 in these collections it is apparent that the last and possibly those at 

 62mm. belong to the second group. The average size of the fifty-four 

 sprats assigned to the first series was 48"3nim., or li inches, including the 

 two at 62mm., and the mean size, i.e., coinciding with the central point 

 of the base line from the smallest to the largest, is also 48mm. This 

 might appear to be the size of sprats ten or eleven months old, belonging 

 to the previous spawning season, and it is considerably under the size 

 assigned by Jenkins to those of one year's growth, although the amount 

 of growth from the middle of April to the early part of June, the period I 

 have taken as representing the maximum of hatching, would add several 

 mm. to their length. The average agrees better with the size of the 

 sprats from the Thames in April examined by Matthews, viz., two inches. 

 On 12th December, however, four months earlier, a haul with the small- 

 meshed net in the same locality in from eight to twelve fathoms furnished 

 seventy- four sprats, of which the first series numbered forty-seven, 

 ranging in size from 49mm. to 60mm., the average being 55'5mm., and 

 the mean 54'5mm. This shows that the collection in April was not fully 

 representative of the series. By combining the two collections the average 

 size of the 98 sprats of this series is found to be 5r3mm., or 2 inches — 

 the range in size being from 40mm. to 60mm., and the mean size 50mm. 

 The date intermediate between the collections is about 14th February, 

 and the size stated may be taken as approximately representing the 

 average size of the sprats at this date. Growth is slow at this time of 

 year and on to April, and an examination of the other curves shows that 

 the end of the first series is about 6cm. when the sprats are about one year 

 old, the average size being a little over 50mm., or slightly over 2 inches. 



There was no collection in February, and that made at the end of 

 March in the Dornoch Firth did not include any of the smaller forms 

 In St. Andrews Bay MTntosh obtained sprats on 12th March in the 

 bottom trawl-tow-net, measuring from 1;|; to 2 inches (32 - 50mm.); and on 

 12th April one 2 inche.'* long, and floating eggs of the sprat two days later.* 



The older series are present in the collections in greater numbers, but 

 as is usually the case it is frequently a matter of difficulty to fix exactly 

 the point of division between them, owing to the overlapping of one series 

 with another and often the small numbers of the fish of one of the series. 



Taking the hauls in the order of the months, the first was on 15th 

 January off Aberdeen, and of sixteen sprats obtained three belonged to 

 one series with an average size of 87 mm., and the other thirteen ranged 

 in size from 112 to 135mm. The larger of these probably belonged to a 

 still older series., but the average for the lot was 123 mm. Another haul 

 in January in the Cromarty Firth furnished twenty-seven sprats, of which 

 twenty-three, measuring from 61 to 92mm., formed one series with an 

 average size of 77'2mm., and the other four belonged to the older group, 

 measuring from 111 to 117mm., and with an average of 114mm. 



If these two January hauls are combined the first group, with a range 

 from 61 to 92mm., has an average size of 78'3mm., and the second, with 

 a range of from 111 to 135mm., an average of 120"9mm. 



1^0 collection was made in February, but on 31st March 870 were taken 

 in the Dornoch Firth. Of these, 205 ranged in length from 75 to 107 

 mm., the average being 96'8mm. ; and the other 665 formed a series 

 from 108 to 139mm., with an average of 117'8mm. The latter series of 

 sprats were ripe and approaching ripeness. 



In April the collection in Aberdeen Bay, besides the fifty-four small 



* Eleventh Ann. Rrp. Fishery Board for Scolland, Partiii., p. 300. 



