254- Mr. Yarrell on the supposed Identity 



abundance in the Thames, from the first point of land beyond 

 Greenwich, opposite the Isle of Dogs, to the distance of a mile 

 below, and immense quantities are taken every year. Formerly, 

 great quantities of Shads were caught by fishermen at that part 

 of the Thames opposite the present Penitentiary, but the state 

 of the water has driven the fish higher up the stream, and the 

 fishing for them at this point has been ahnost abandoned. 



Very considerable numbers of Shads were also taken in 

 former seasons as high up the river as Hammersmith, but the 

 deterioration which the quality of the water has suffered from 

 various causes, has rendered the fishing for Shads in this part 

 of the river an employment scarcely worth following: the 

 quantity of fishes obtained in a season twenty years ago, com- 

 pared with the produce of the present year, would be in the 

 proportion of an hundred to one. 



By various acts of Pai'liament*, the conservation of the river 

 Thames from Staines Bridge downwards, and of the waters of 

 the Medway, is vested in the Lord Mayor and his Court for 

 the time being, who, with the addition of certain other officers, 

 make and enforce the execution of their own bye-law^s for the 

 preservation of the fishery. Their 23rd rule and order is as 

 follows: " Shads shall be only taken from the 10th day of 

 May to the 30th of June in every year." 



By making an arrangement both at Putnej'^ and Greenwich, 

 I was constantly supplied with Shads twice in every week du- 

 ring the whole, and even somewhat beyond the time they are 

 allowed to be taken ; and without going into a detail of weekly 

 observations, it will be sufficient for tlie purpose to state, that 

 not a single male or female Shad, e?;amined during die months 

 of May or June, had cast its milt or eggs, and this fact it is 

 necessary to bear in mind. Two fishes examined on the 5th 

 of July still retained their roes, but two others subjected to the 

 same test on the 7th had passed their ova. 



It is the opinion of the fishermen, who have the best op- 

 portunities for observation, that these adult fishes, having per- 

 formed the office for which they visit the fresh water, take the 

 centre of the current and return to sea. From their weak state, 

 they may be said to drift, rather than swim, with the tide, and, 

 as fishing against the stream is prohibited, they in this way 

 proceed in safety to their destination. 



Of the young Shad, when vivification of the deposited ova 

 lias takenplace, but few examples are caught, and these only 

 by the unlawful mode of fishing for Whitebait. Like the young 

 of Salmon, and the fi-y of other salt-water fishes, instinct di- 

 rects the exertion of their first effijrts towards gaining the sea. 



» 13 Edward T. c. 47. 17 Richard 11. c. 9.; and 10 Anne. 



The 



