REARING OF BIVALVE MOLLUSKS
36
to removal by algae of certain chemicals from sea water that am
essential @ k a l development.
C. Me&& of cultivdion of eggs and h m
Methods of culturing eggs and larvae of bivalves under laboratory
and small-sde hatchery conditions have been tested by many workem
for over 100 years. Costki, a Frenchman, was probably the first to
attempt this mound 1868. In the United States a number of extremely
capable men, including Brooks (1880), Ryder (1883) and Winslow
(1884), continued these efforts on C. virginica, but were unsuccessful.
Perhap the beef summary of theae efforts ie given by Winslow, who
states, “ But after my experience of the peet spring and summer I am
oonvinced that it will require a series of painstaking experimenfs,
extending over oonaiderable time and conducted under many diesimilar
conditioqs, before the artificiel production and culture of the oy&x is
made a matter of prrtctitx.1 importance.”
Inter& in artificial propagation of bivalves was revived when
Prytherch (1924) and W e l l s (1920, 1927) succeeded in carryhg oyster
h a e to metamorphosis. This success wm probably due to the practice
of renewing the water in which oyster larvae were kept. Wells used 8
milk separator for this purpose, while Prytheroh ueed filtros plates.
Other suocessful workers in this field included Hori and Kusakabe
(1926), Cole (1936), Bruce et d. (1940), Lindsay and Woelke (1960),
Woelke (1960) and, especially, Imai et d. (1950b). In our,- some
oysters were carried to metamorphosis as early as 1932, but efforts
to repeat this succ8g~ usually failed until about 1946-1947 when we
began to develop and improve the methods used at our laboratory
(Loosanoff and Davis, 1960 ; Davis, 1963 ; Loosanoff, 1964).
It is our practice to fertilize eggs m soon a8 they am dhhrged.
Usually it happens automatidy because since we use a sperm suepension to stimulate spawning, spermatozoa are already present in
the water when females begin to discharge eggs. b h , actively-moving
sperm are used to assure normal fertilization of eggs and development
of zygotes. Sufficient quantities of sperm are always added, but when
working with small eggs, such as those of C. virgin*, which cannot
be retained even by fine screens, we limit the quantity of suspension.
In this way excessive quantities of sperm are not carried into our
culture vessels, and the undesirable effects of decomposing sperm on
developing eggs are avoided.
The bivalves are usually spawned in Pyrex glass dishes containing
about 1.6 litemof water(Figs. loand 11). As haealrdybeenmentioned,
to separate the eggs from the debris and, later, from the excess sperm,
4
36
to removal by algae of certain chemicals from sea water that am
essential @ k a l development.
C. Me&& of cultivdion of eggs and h m
Methods of culturing eggs and larvae of bivalves under laboratory
and small-sde hatchery conditions have been tested by many workem
for over 100 years. Costki, a Frenchman, was probably the first to
attempt this mound 1868. In the United States a number of extremely
capable men, including Brooks (1880), Ryder (1883) and Winslow
(1884), continued these efforts on C. virginica, but were unsuccessful.
Perhap the beef summary of theae efforts ie given by Winslow, who
states, “ But after my experience of the peet spring and summer I am
oonvinced that it will require a series of painstaking experimenfs,
extending over oonaiderable time and conducted under many diesimilar
conditioqs, before the artificiel production and culture of the oy&x is
made a matter of prrtctitx.1 importance.”
Inter& in artificial propagation of bivalves was revived when
Prytherch (1924) and W e l l s (1920, 1927) succeeded in carryhg oyster
h a e to metamorphosis. This success wm probably due to the practice
of renewing the water in which oyster larvae were kept. Wells used 8
milk separator for this purpose, while Prytheroh ueed filtros plates.
Other suocessful workers in this field included Hori and Kusakabe
(1926), Cole (1936), Bruce et d. (1940), Lindsay and Woelke (1960),
Woelke (1960) and, especially, Imai et d. (1950b). In our,- some
oysters were carried to metamorphosis as early as 1932, but efforts
to repeat this succ8g~ usually failed until about 1946-1947 when we
began to develop and improve the methods used at our laboratory
(Loosanoff and Davis, 1960 ; Davis, 1963 ; Loosanoff, 1964).
It is our practice to fertilize eggs m soon a8 they am dhhrged.
Usually it happens automatidy because since we use a sperm suepension to stimulate spawning, spermatozoa are already present in
the water when females begin to discharge eggs. b h , actively-moving
sperm are used to assure normal fertilization of eggs and development
of zygotes. Sufficient quantities of sperm are always added, but when
working with small eggs, such as those of C. virgin*, which cannot
be retained even by fine screens, we limit the quantity of suspension.
In this way excessive quantities of sperm are not carried into our
culture vessels, and the undesirable effects of decomposing sperm on
developing eggs are avoided.
The bivalves are usually spawned in Pyrex glass dishes containing
about 1.6 litemof water(Figs. loand 11). As haealrdybeenmentioned,
to separate the eggs from the debris and, later, from the excess sperm,
4