of the Fishery Board for Scotland. 



397 



whereas at West Loch Tarbert and at Stranraer it coincides with that of 

 the end of April and the second week of October. 



The ranges of mean monthly temperatures of the surface water at the 

 various stations are compared in the following table : — 



Range of Temperature between Warmest and Coldest Months. 





1892. 



1891. 



Station. 





















Forenoon. 



Afternoon. 



Forenoon. 



Afternoon. 



East Coast. 



o 



7-3 



o 



7'5 



o 



7*7 



o 



7-6 



Bell Rock, . 



North Carr, . 



8-3 



8-5 



7-5 



7-9 



Abertay, 



8-4 



8-2 



8-9 



87 



Oxcar, .... 



9-3 



9-2 



10-4 



10-8 



West Coast. 











Stranraer, 



12-2 





11-6 





West Loch Tarbert, 





11*3 





12-1 



Ardrishaig, 

 Brodick, 



7 : 3 



7'0 



8-0 



8-2 



7-3 



7'4 



6-8 



7'0 



The extreme ranges of surface temperatures are given in the following 

 table : — 



Range of Temperature between Warmest and Coldest Days. 



Station. 



1892. 



1891. 



1890. 



East Coast. 







o 



9-5 



Bell Rock, 



8°-6 



8-6 



North Carr, 



10*9 



10-3 



9-3 





11 -8 



12-4 



10-3 



Oxcar, 





14-4 



10-2 



West Coast. 









Stranraer, 



15-5 



15-4 





West Loch Tarbert, .... 



14-8 



15'2 





Ardrishaig, 



137 



9-6 



12-5 



Brodick, ...... 



10-4 



11-2 





The stations where the range of temperature is least are those where 

 the land has not so much influence, and where the mean temperature of 

 the surface water is latest in being reached. On the other hand, the 

 most land-locked stations are the places where the extremes are greatest, 

 and where the heating of the air and the land very quickly affects the 

 temperature of the water. 



These facts being ascertained, it is of importance to find how far these 

 marked temperature differences affect the distribution and catch of fish, 

 and how far they are of importance compared with the other physical 

 conditions, such as situation and the admixture of fresh-water. 



The Stranraer and Loch Tarbert records are so important that the 

 observations have been published in full, and curves drawn to show the 

 daily march of temperature. These curves have an appearance of 

 rhythmic variation which suggested that tidal changes might explain 

 many of the ups and downs that occur at fairly regular intervals. Accord- 



