14 Old Influences still at Work ; Abundant Fish-food. 



6. General Results. Taking into consideration what pre- 

 cedes, it seems a legitimate inference that the present conditions 

 of the whole coast of our Sea- Fisheries District amply bear 

 witness to a permanent influence of former times, notwithstand- 

 ing the wondrous changes which have occurred during the 

 lapse of ages. 



Seeing that the English Channel is the near cut of ocean 

 route to the Thames Estuary, one would expect its influence 

 paramount. Instead, the Atlantic gulf-stream, with its con- 

 tingent of colder Arctic water, comes by the long route round 

 Scotland and swoops into the North Sea. A funnel-shaped 

 offset of the North Sea current, or perhaps flood tide-wave, 

 presses the water along the Suffolk and Essex coasts, ter- 

 minating in the ^Thames Estuary and adjoining rivers. The 

 ebb-tide of stronger and longer duration returns in the same 

 course. Thus it is that the surface-floating lower organisms 

 ("Plankton" of science) and fish-food, at times swarming in 

 myriads, are almost all of the types or allied to northern forms, 

 as are the great majority of the fish.* 



Then this bight of the southern section of the North Sea, 

 comparatively shallow (save in a narrow middle strip of some 

 20 to 30 fathoms depth) shorewards, harbours mussels, cockles 

 and worms in plenty, with crustaceans varied and numerous ; 

 all these furnishing the bulk of the flat-fish food. Again, the 

 many sand-banks offshore (see chart diagram) are doubtless, 

 with exceptions, the chief spawning-grounds and rendezvous of 

 certain of the mature fish whose floating spawn and brood 

 crowd the inner estuary in due season. 



Lastly, as is well known, the North Kent and the Essex 

 shores are famous for their oysters and other edible shell-fish. 

 This is greatly dependent on the physical formation of the 

 district. The shallow waters conduce towards a congenial 

 temperature. Then their salinity just hits the happy medium, 



* Consult Cunningham and Holt's " North Sea Investigations," and especially the 

 former's "Physical and Biological Conditions in the North Sea," where species 

 entering from north and south are discussed. Jour. Mar. Biol. Assoc., Vols. II., III., 

 IV. (1891-7). 



