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Cull Policy

It is necessary for the NCMA to develop a cull policy to help reduce strain redundancy in our current collection and to allow room for more diverse and scientifically interesting strains to be accessed. This is a critical part of collection management since it is difficult to support new accessions with limited resources. We have not considered an organized culling of the phytoplankton collection in over 25 years. We hope that our users will agree with our decisions. 

Strains will only be culled from the live collection. We will not cull strains that have had their genome sequenced, type strains, authentic strains, strains with a large publication record, or strains in our current cryopreserved collection since 50% of our strains are known to survive cryopreservation.  At least 3 of the following criteria must apply before a strain is culled:

  • Multiple strains of the same species, especially those that were collected at the same time from the same location and have not been ordered within the 5 years.
  • Multiple isolates of the same strain from the same location and have not been ordered within the 5 years.
  • Strains growing poorly and cannot be distributed.
  • Strains contaminated with fungi that we have been unable to r-isolate.
  • Rarely ordered strains (defined as no requests for that strain in 5 years).
  • No publication record for the strain.
  • The strain is held by another collection.
  • Marine strains will take priority (for saving) over freshwater strains. 

Every effort will be made to inform the original depositor of our intention to cull a strain. A cull list will be posted on our website giving at least 30 days notice prior to initiation of the cull process for strains on that list. We will reconsider a specific strain(s) cull if either the depositor, or the wider academic and/or business communities present convincing reasons to the Head Curator and Director. 

By using the above criteria and the decision-making flowchart (see Figure 1), we will cull at least 20% (500 – 600 strains) of the algal collection without loss of any taxonomic diversity, geographical/ecological range, or scientific relevance. Importantly, it will free up capacity by urators to allow us to actively access new and potentially interesting strains.