92 BRITISH FISHERIES 



necessity for the investigation of the effects of 

 various kinds of fishing on the abundance of fish 

 on a fishing ground, and that this should be done 

 was one of the chief recommendations of the 

 Commission. It was thought that valuable results 

 might be obtained by excluding trawl fishermen 

 from some particular area, and observing for a 

 number of years any effect which this cessation 

 of fishing might have on the fauna of the ground. 

 Certain areas off the east coast of Scotland were 

 therefore closed by by-law, under the powers con- 

 ferred by the Sea-Fisheries (Scotland) Amendment 

 Act of 1885; definite "stations" or trawling 

 lines were marked out on the chart ; and monthly 

 trawling experiments were made over these stations. 

 The procedure in these experiments was to trawl 

 on every occasion with uniform fishing gear for 

 a certain time, and always over the same strip 

 of ground. The fish caught were then counted 

 and recorded, and at the same time a number 

 of other observations — the identification of the 

 invertebrate animals caught by the trawl ; the 

 determination of the " plankton " by " tow-net " 

 experiments ; physical determinations, such as 

 the temperature and specific gravity of the 

 sea-water ; and meteorological observations — were 

 made and recorded. All these observations 

 (which are published in the Annual Reports 

 of the Board) were collated year by year, and 

 deductions were made as to the apparent changes 



