ZOOLOGY. 271 



ProvincetoAvn Harbor. They are found now in great abundance. 

 They make their appearance in June, coming into the harbors all at 

 once, and driving away the mackerel entirely. On one occasion they 

 came on the 22d of June ; the day previous 8,000 mackerel were 

 caught in the harbor ; on the 22d, not one was to be found. They 

 leave the coast with the appearance of the first cold northeast storm, 

 about the last of September, though two or three individuals were 

 taken in Provincetown, December, 1862. They have only recently 

 come into the market, for several years ago scarcely any were sold ; 

 but during the past season, he alone had brought to the market 45,000 

 pounds weight. 



Since their great increase, the lobsters (H&marus americanus Dekay) 

 had multiplied four-fold, for the natural enemies of their young had 

 been driven away by the blue-fish. Formerly these fish appeared in 

 large shoals near the surface, constantly ' ; flouncing out " of the water, 

 and they were caught in sweep seines and by the hook ; now, though 

 they come in large quantities, they seem to prefer the deeper waters. 



Mackerel (Scomber vernal is Mitch.) also had changed their habits 

 much. The former method used in catching them was by dragging 

 hooks on lines twenty fathoms long, and constantly raising and lower- 

 ing them ; now they are caught at the surface with bait, large quanti- 

 ties of it being strewn alongside to attract them. The bait used is 

 generally the poorer mackerel, ground up. The former method of ob- 

 taining them has now entirely failed. 



The Cod (Morrhua americana) upon the Banks of Newfoundland 

 seem also to have changed their habits. Formerly, all the fish were 

 caught on board of the vessels while lying at anchor. The vessels 

 take a crew of eight men, each using two lines ; when the fish were 

 abundant, all the men would fish, but usually not more than half the 

 crew ; at times, when no fish could be taken, all the lines but one 

 would be drawn in, and then they would begin to be taken abundant- 

 ly ; but let two or more men begin to drop their lines, and not an in- 

 dividual would be taken; while, should all the lines but one be again 

 taken in, the captures would once more be frequent. This suggested 

 the idea of carrying small boats with them, so that each man could fish 

 apart from the others, and in this they met with perfect success; and, 

 generally, when all the fishermen in the boats would catch them plen- 

 tifully, few or none could be taken from on board the vessel. Capt. 

 Atwood thought that the cause was the different motion of the small 

 boats from the vessel, as there is constantly an agitation of the waves 

 upon the Banks. 



THE HEARING OF FISHES. 



Fishes can do no more than be sensible of a noise. They cannot 

 distinguish modulations or differences of tone. 



One is reluctant to destroy a pet idea, however poetical and pretty, 

 yet the searcher into scientific truths is often compelled to do so. It is 

 so in this instance, for truth compels the assertion of the impossibility 

 of the supposed fact that fishes delight in musical sounds, or come to be 

 fed by the attraction of a whistle. The true explanation is, that the 

 vibration of the footstep, not of the whistle, is the source of attraction. 

 This may be proved by a walk along the margin of any canal or pond. 



