EUROPEAN METHODS OF OYSTER-CULTURE. 
367 
can not fail to have a similar effect. Seed oysters are accordingly imported, mainly 
from Arcachon, on account of cheapness. 
Efforts to regulate the banks after the method of M. Coste were recommended 
and experimented upon by M. Graells,* by royal commission, unsuccessfully. 
In the markets of Lisbon the only obtainable oyster is the species known generally 
as the Portuguese ( Ostrea angulata). This species, introduced into France a quarter 
of a century ago and a little later into England, has proven of great commercial 
importance. It is hardy, prolific, and rapid in growth, and in cheapness of produc- 
tion it makes undoubted amends for its poorness in quality, t As this species has long- 
been known to be related to the American oyster in sex character, it has seemed of 
interest to ascertain its native living conditions and to what degree it has been locally 
cultivated. The Portuguese oyster is described as occurring in river mouths along 
the west coast of the Spanish peninsula. It appears to attain its best conditions 
along the southern coast of Portugal, but may be studied not unfavorably near Lisbon 
in the widened mouth of the Tagus. 
The harbor of Lisbon is aminiature sea, a mile or more in width and half a dozen 
miles long, its entrance being formed by a narrows a third of a mile wide and 2 miles 
long. The southern shore of this sea, opposite the city, is the home of the oyster; it 
has shallow water, curving beaches, and incurrent freshened streams. It commences 
at the narrows opposite the city markets, Cacilhas, sweeps southward, then eastward, 
then northward, where the river begins to take upon it the tawny color of the u mer 
depaille It would naturally seem from the constricted mouth of the river that .the 
water of the harbor would be considerably freshened, as it doubtless is at certain 
seasons, but the included water volume is so great and the sea inlet so deep that the 
incurrent fresh water is not apparently felt within 10 miles of the coast. Eight miles 
from the mouth of the Tagus the density, on October 1 to 3, 1891, continued as high 
as 1.0235, at 67° F, while the bulk of the water appears to average 1.0245 to 1.025 
(67° F). At the Lisbon custom-house, in the current of the narrows, the density 
reaches 1.0264 (67° F). A gravelly shoal extends from Cacilhas, fringes the southern 
shore, and furnishes the site of a natural oyster bed, very favorably conditioned. 
The water is here shallow for a quarter of a mile off shore; the bottom is a compact 
crust of sand, gravel, and tawny mud, though it is often exceedingly soft below; it is 
usually densely carpeted with a fine ulva, not enough to stifle the oyster growth and 
perhaps contributing to its support as a purveyor of oyster food. 
From time immemorial the region has been rich in oyster production, and for 
years has not merely furnished the Lisbon market, but has been the center of active 
export. The original cargo that gave accidental origin to the Freuch-Portuguese 
oyster was taken from this neighborhood. The ease with which the angulata could be 
collected, its cheapness and hardiness during transport, have for a long time made 
its export considerable. An English company a dozen years ago secured a fishery 
franchise and supplied the English market with Anglo-Portuguese oysters, shipping 
them in great quantity to the grounds of the Thames estuary and there fattening 
them for several months. This export was continued until the company became 
* U. S. F. C. Bulletin, 1890, reference list, pp. 385-388, Nos. 42 a and />, 12c, p. 200; also Francisco 
Garcia Sola, Fisheries of Spain, Int. Fish. Exhibition, London, 1883; extract in Philpots’, p. 693; D. F. 
Balaguer y Primo, Cria de los Peces, de Guesta, Madrid, 1878, pp. 47 et seq. 
t U. S. F. C. Bull., 1890, p. 366; also in reference list, pp. 385-388, Nos. 7 d, 9 c, d, e, f, 12, 14, 37, 
39, 51, 63 a, b, c, 82. 
