2
VICTOR L. LOOSANOFF AND HARRY C. DAVIS
I. INTRODUCTION
Until recently rearing of larvae and juveniles of marine bivalves,
on a basis where repeatable results could be expected, was virtually
impossible because of the lack of satisfactory, reliable methods. Thus,
although culturing of larvae of bivalves was first attempted in the last
century, few workers succeeded in rearing them to metamorphosis and,
as a rule, they were rarely grown beyond early straight-hinge stage.
Even though, in the twenties, Wells (1927) was able to rear the American
oyster, Cramoetrea virginica, from artificially-fertilized eggs to epat, and
Prytherch (1924) raised larvae of the same species in large numbers,
their results could not be consistently repeated by other investigators.
The failures were usually due to poor culture methods and want of
good food for the larvae, especially when they were grown in heavy
concentrations. It is also possible that diseases, including those caused
by fungi, were responsible for the persistent failures.
Attempts to rear larvae of bivalves were not confined, of course, to
C. virginica. Cultivation of larvae of several other species was a h
tried by early workers. For example, Belding (1912) attempted to
raise larvae of clams, Hercenuria nzercenaria (formerly Venm mrcenaria), but without success. He concluded that there was no practical
method for raising clam larvae to straight-hinge stage because of the
small size and delicate nature of the egg. Wells (1927), however, was
more successful and carried the clam larvae in his cultures until they
metamorphosed.
Even in more recent years the situation remained practically the
same. This is well demonstrated by the work of Yoshida (1963) who,
in his attempts to identify larvae of Japanese bivalves, had to depend
upon obtaining the larvae from plankton, instead of trying to grow them
from fertilized eggs under controlled laboratory conditions where their
identity would be assured. The difficulties experienced as recently as
1953 by Nikitin and Turpaeva (1959), in their attempts to raise l&rves
of some bivalves of the Black Sea by using old methods, vouch for
the inefficiency of these now obsolete approaches.
Obviously, as the general studies of marine organisms progress, the
necessity for methods by means of which bivalve larvae can be reared
successfully becomes more and more urgent. The availability of such
methods would immediately offer the opportunity to study the effects
of numerous environmental factors, singly and in combination, upon
the growth of larvae, thus helping to determine the physiological
requirements of these organisms. It would also offer the means for
studying the genetics of bivalves and initiating properly controlled
experiments on selective breeding of these mollusks. Moreover, by
VICTOR L. LOOSANOFF AND HARRY C. DAVIS
I. INTRODUCTION
Until recently rearing of larvae and juveniles of marine bivalves,
on a basis where repeatable results could be expected, was virtually
impossible because of the lack of satisfactory, reliable methods. Thus,
although culturing of larvae of bivalves was first attempted in the last
century, few workers succeeded in rearing them to metamorphosis and,
as a rule, they were rarely grown beyond early straight-hinge stage.
Even though, in the twenties, Wells (1927) was able to rear the American
oyster, Cramoetrea virginica, from artificially-fertilized eggs to epat, and
Prytherch (1924) raised larvae of the same species in large numbers,
their results could not be consistently repeated by other investigators.
The failures were usually due to poor culture methods and want of
good food for the larvae, especially when they were grown in heavy
concentrations. It is also possible that diseases, including those caused
by fungi, were responsible for the persistent failures.
Attempts to rear larvae of bivalves were not confined, of course, to
C. virginica. Cultivation of larvae of several other species was a h
tried by early workers. For example, Belding (1912) attempted to
raise larvae of clams, Hercenuria nzercenaria (formerly Venm mrcenaria), but without success. He concluded that there was no practical
method for raising clam larvae to straight-hinge stage because of the
small size and delicate nature of the egg. Wells (1927), however, was
more successful and carried the clam larvae in his cultures until they
metamorphosed.
Even in more recent years the situation remained practically the
same. This is well demonstrated by the work of Yoshida (1963) who,
in his attempts to identify larvae of Japanese bivalves, had to depend
upon obtaining the larvae from plankton, instead of trying to grow them
from fertilized eggs under controlled laboratory conditions where their
identity would be assured. The difficulties experienced as recently as
1953 by Nikitin and Turpaeva (1959), in their attempts to raise l&rves
of some bivalves of the Black Sea by using old methods, vouch for
the inefficiency of these now obsolete approaches.
Obviously, as the general studies of marine organisms progress, the
necessity for methods by means of which bivalve larvae can be reared
successfully becomes more and more urgent. The availability of such
methods would immediately offer the opportunity to study the effects
of numerous environmental factors, singly and in combination, upon
the growth of larvae, thus helping to determine the physiological
requirements of these organisms. It would also offer the means for
studying the genetics of bivalves and initiating properly controlled
experiments on selective breeding of these mollusks. Moreover, by