Report on the Lancashire sea-fisheries laboratory at the University of Liverpool, and the Sea-fish hatchery at Piel .. . — — — 1 1 1 Lemon 1 Skates 27 ^l 1 138 20 Rays 11 Totals 61 242 26 186 158 404 The area trawled over is shown in the accompanyingsketch chart, where the positions, directions and lengthsof the six hauls are marked. It will be seen that they arerestricted to a narrow strip round the west and north sidesof the bay. The depth was very uniform, 4 to 6 fathoms,and the bottom everywhere consisted of sand. The areawas, in fact, a limited one, where the physical conditions 8G
Report on the Lancashire sea-fisheries laboratory at the University of Liverpool, and the Sea-fish hatchery at Piel .. . — — — 1 1 1 Lemon 1 Skates 27 ^l 1 138 20 Rays 11 Totals 61 242 26 186 158 404 The area trawled over is shown in the accompanyingsketch chart, where the positions, directions and lengthsof the six hauls are marked. It will be seen that they arerestricted to a narrow strip round the west and north sidesof the bay. The depth was very uniform, 4 to 6 fathoms,and the bottom everywhere consisted of sand. The areawas, in fact, a limited one, where the physical conditions 8G were everywhere constant, and where, if those conditionsdetermined the distribution of the fish, one would haveexpected a similarity of result in the hauls made. These,however, show the most remarkable differences. Haul 6may be left out of consideration as it was longer thanNos. 1 to 5, but in those five hauls the number of plaicecaught varies from 14 to 157, of dabs from 8 to 67, and ofray from 0 to 38. The only variable condition is thestate of the tide, and there are no apparent regularities Port Williain. Burrow Hd. Fig. 4.—Luce Bay, shewing the positions, approximate directionsand lengths of the drags. to be seen by comparing the catch with this is no doubt, of course, that the state of the tide didaffect the number of fish caught, but the variation in thecatches due to this cause is apparently disturbed byvariations due to the irregular distribution of the fish onthe bottom. The same results are given by hauls made by a shrimptrawl on tlie Mersey grounds. The following table givesthe result of four hauls made by the same boat during the 87 same dav on a very limited area—tlie deposit hauls were made immediately after each other, andthe length of ground trawled over varies slightly, but inan insufficient degree to account for the difference in thecatches. Four hauls made on the Mersey Deposit groundon February 16th, 1894. I. i hr. ebb
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectfishes, bookyear1902
