4 - Central Institute of Brackishwater Aquaculture

the cells to prevent intraceilular ice crystal formation. The preservation of flsh
semen and blastomeres are a success story for germplasm conservation through
cryopreservation. More than 200 fish species with external fertilization have been
tested for sperm cryopreservation. The present state of art for many species of fish
seems to be adequate for the purpose of gene banking and germplasm
conservation.
5. Management of Gene Bank Information
A huge amount of information is required to manage the broad range of activities
that are essential for an operating gene bank such as population sampling
procedures, sample identification, tissue processing, cataloging, information
retrieval, quality control and sample disposition. Gene pool preservation requires
that a sufficient number of individuals be collected to effectively sample the total
available gene pool and to achieve the gene and genotype frequencies which are
representative of the source population. The actual number of individuals
necessary to achieve this goal is ambiguous and debatable, but the criteria most
commonly used is the smaller of a predetermined percentage of the total
population (10-100%) or an upper limit number of individuals (100, 400 or more)
that sampling theory indicates is sufficient (Kincaid, 1983, Ryman,l991). Once milt
is collected, a sample identification system is applied to ensure positive
identification of each sample during all handling procedures (species, date, time,
processing, storage, monitoring and retrieval operations). A quality control
program is needed to ensure that high viability is maintained. A milt replacement
program is also needed to ensure that the deteriorated milt is replaced or removed
for breeding programs.
Gene bank information is primarily of two types: 1) Gene bank operations
information to catalog and manage the stored tissues, and 2) gene bank user
information to characterize the source population and determine the most effective
applications for stored tissues. The database must include the information needed
to accomplish the following functions:
1. Sample and population identificaqon procedures.
2. Collection procedures.
3. Sample processing procedures.
4. Sample storage and retrieval operations.
5. Quality monitoring.
6. Inventory maintenance.