UHAPTER 3
SIGNIFICANCE OF UNDERSTANDING SY M BlONTS
OF MARINE MOLLUSCS
The original intent of this review was to summarize what is known
about the parasites of commercially important marine molluscs.
However, as the search of the literature progressed, it became
increasingly evident that very little is known about the more subtle,
yet important, aspects of parasitism among these associations. As
would be expected, many organisms have been reported to parasitize
commercial molluscs and there have been some not too discrete
statements as to the pathogenicity and lethality of certain of these
parasites. There is also some information pertaining to geographic
distribution. Unfortunately, these pieces of information hardly
sufficed in assembling a continuous and natural description of parasitism. For this reason, the topic was broadened to include information
that exemplifies the mechanisms involved in all types of symbiotic
associations and on all types of molluscs, but without losing sight that
the marine species are of primary concern in this review. Despite this
change in plans, an annotated list of known parasites of economically
important marine molluscs is given in Chapters 5-9. Many individuals
have urged that this be done because up until this time no such list
exists ; this has resulted in hardships for certain marine biologists,
shellfishermen and fisheries biologists who do not have access to the
large variety of journals in which such information is distributed.
The significance of understanding symbioses of which marine
molluscs, especially the commercial species, serve as hosts can be
explained from three major viewpoints: (a) that of the fisheries
biologists and shellfishermen ; (b) that of the public health officer, and
(c) the more fundamental one of the biologist.
I. IMPORTANCE TO SHELLFISHERIES
There is no need to belabor the importance of symbionts, especially
parasites, to the fisheries biologist and shellfishermen. Several mass
mortalities of shellfish, particularly of oysters, throughout the world
during the last five decades have aroused the concern of the industry.
Oyster mortalities since the 1910s throughout the world have been
la
SIGNIFICANCE OF UNDERSTANDING SY M BlONTS
OF MARINE MOLLUSCS
The original intent of this review was to summarize what is known
about the parasites of commercially important marine molluscs.
However, as the search of the literature progressed, it became
increasingly evident that very little is known about the more subtle,
yet important, aspects of parasitism among these associations. As
would be expected, many organisms have been reported to parasitize
commercial molluscs and there have been some not too discrete
statements as to the pathogenicity and lethality of certain of these
parasites. There is also some information pertaining to geographic
distribution. Unfortunately, these pieces of information hardly
sufficed in assembling a continuous and natural description of parasitism. For this reason, the topic was broadened to include information
that exemplifies the mechanisms involved in all types of symbiotic
associations and on all types of molluscs, but without losing sight that
the marine species are of primary concern in this review. Despite this
change in plans, an annotated list of known parasites of economically
important marine molluscs is given in Chapters 5-9. Many individuals
have urged that this be done because up until this time no such list
exists ; this has resulted in hardships for certain marine biologists,
shellfishermen and fisheries biologists who do not have access to the
large variety of journals in which such information is distributed.
The significance of understanding symbioses of which marine
molluscs, especially the commercial species, serve as hosts can be
explained from three major viewpoints: (a) that of the fisheries
biologists and shellfishermen ; (b) that of the public health officer, and
(c) the more fundamental one of the biologist.
I. IMPORTANCE TO SHELLFISHERIES
There is no need to belabor the importance of symbionts, especially
parasites, to the fisheries biologist and shellfishermen. Several mass
mortalities of shellfish, particularly of oysters, throughout the world
during the last five decades have aroused the concern of the industry.
Oyster mortalities since the 1910s throughout the world have been
la