450 REPORT ON TRAWLING AND OTHER INVESTIGATIONS 



these fishes are numerically in excess * of the plaice, though slightly, 

 and a far larger proportion of them attain the marketable size. In 

 Start Bay alone are the marketable plaice in excess of the small ones, 

 and these they outnumber by eighteen to one. 



The problem of the bays, so far as it is a biological one, clearly hinges 

 upon the plaice, and in the succeeding sections our records of the dis- 

 tribution and sizes of this fish have been accordingly subjected to a 

 much closer analysis than those of the other species. 



START BAY. 



The following description of the trawling-grounds has been provided 

 by Dr. Kyle :— 



"The area closed by the by-laws includes about twenty- five square 

 miles, but owing to the presence of crab-pots on the Skerries Bank 

 and of rocks along the shore, the trawling-grounds are reduced to 

 fifteen square miles. The bottom-soil is of three distinct kinds. 

 Coarse sand to gravel is found along the shore from Blackpool to 

 Hallsands, extending outwards about a hundred yards off the former; 

 but off Hallsands it stretches right round the promontory, and extends 

 outwards to join on to similar soil along the inner and outer margins 

 of the Skerries. In the centre of the bay the soil is of medium to 

 fine sand, whilst round Dartmouth Fairway it is of mud. As mentioned 

 in a separate paper, storms make considerable alterations, for the time 

 being, in the distribution of the various soils throughout the bay. 

 During neap tides there is very little movement of the water in the 

 centre of the bay, but during spring tides a current of two to three 

 knots runs through it. This is stronger on the ebb and alongshore, 

 where a two and a half to three hours' eddy on the latter half of the 

 flood makes with the ebb a nine hours' current flowing from Slapton 

 Sands to the Point. The presence of this current is of considerable 

 importance, as it prevents the bay from becoming foul with drift-weed, 

 mud, jelly-fishes, diatoms, etc., a fate which periodically overtakes the 

 other bays during the summer. For this reason the sand of Start Bay 

 is particularly clean and bright-coloured, and the plaice which live 

 there have the same qualities. The brightness of their orange- 

 coloured spots and tlie shiny appearance of their skin readily dis- 

 tinguish them from those of any other region. It is probable, also, 

 that the general cleanliness of the bay has some influence for good 

 on the invertebrate fauna which constitutes their food ; certainly the 

 plaice from Start Bay used to obtain the highest price on the market. 



* As shown below (p. 4.58), this excess, in the case of Start Bay, was limited to the 

 summer season of 1902, when, however, the preponderance of dabs was very conspicuous. 



