12 
It is plain from these figures that Blackpool Bay is very like 
Druridge Bay in our district with regard to the proportion of flat 
fish, and that, therefore, there is no sign that the gradual changes, 
to which attention has been drawn, are continued towards the 
south. 
The experiments of the Scottish Fishery Board in the areas 
immediately to the north show that the various grounds presented 
similar variations, the proportional numbers of plaice and dabs and 
other flat fish varying with the station. 
The bottom at each of the trawling stations is of sand. It is 
already known from the results of experiments on grounds of 
different character that the nature of the fish fauna varies with the 
depth and the formation of the bottom, and it is now evident that 
the surrounding ground also exerts a considerable influence, at all 
events, on areas near the coast. 
5. — Limitations of First Haul Experiment. 
When all the experiments are taken together each year it is clear 
that the evidence of the first haul does not differ widely from that 
of the complete experiment. They point to a general fluctuation 
about a mean such as has also been shown to take place during the 
same period by the complete experiment. Taken separately, how- 
ever, the results obtained by the short experiment do not agree in 
many instances with the longer experiment, and this is true even if 
attention be directed merely to the marketable fish. I have already 
dwelt upon the discrepancies between the two kinds of experiment 
in the report for 1901, and have there shown that while a short 
experiment of an hour or two indicates accurately enough the pro- 
portional numbers of fish on the ground, it is not to be trusted to 
give more than an approximation to annual fluctuations on an area 
liable to variation from such causes as have been mentioned above. 
This is again evident from a comparison of the two classes of 
diagrams in Chart 2. 
Attention must be drawn, however, to the change with regard to 
the relative proportions of plaice and dab amongst flat fish, shown 
in Table X. and in Chart 1. Nothing can be gathered from the 
fluctuations from year to year of the marketable fish, but in the case 
of the first haul, since 1899, there is evidence of a striking dis- 
similarity in the proportions of the two forms, which further 
investigation may prove to be significant. 
