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scavengers, and will subsist largely on dead material. 
Consequently, if there should be any scarcity of food, I 
do not doubt that they might, to some extent, compete 
with the little fish by eating the worms and smaller 
erustacea, but it is improbable that there would be 
any such secareity. We may put great trust in the 
recuperative powers of the invertebrate fauna of the sea- 
bottom. Even in the spots where fishes are most crowded, 
we bring up plenty of invertebrate food material in the 
dredge and trawl; and, moreover, if there were any 
scarcity of food the star-fishes and crabs, which are so 
abundant on these grounds, would move away. 
A greater danger might be brought about by the 
increased numbers of shrimps and young fishes attracting 
many skates, rays and other larger predaceous fishes 
to the ground. In fact, the disturbance of the fauna 
might be very wide spread. Some forms of invertebrata 
might be either favoured or the reverse by the changed 
conditions, and then that change in the food might re-act 
upon the fish population. For example, if the smaller 
crabs which are usually present in enormous profusion on 
the shrimping grounds, found conditions uncongenial and 
migrated to other banks and channels, the Gadoid fishes, 
which feed largely upon such crabs, might in their turn 
be affected. 
The chief enemies of shrimps in our district (see our 
Report for 1894) are skates and rays, whiting, gurnard, 
and the larger Gadoid fishes. The latter are not abundant 
on the shrimping grounds, but skates and rays seem to 
have increased on the Blackpool closed ground, possibly 
as a result of the more abundant feeding upon that 
sanctuary. <A careful detailed comparison of this closed 
area with the open grounds on both sides of it might give 
information as to effects to be expected by closing other 
