[Nhcoll-l] Preservation of a fish collection

[Simon Moore]

Hi Katja,

The specimens would likely have been fixed (initial stage of preservation, from fresh material) in formaldehyde solution and then preserved in alcohol. 

Auto-dilution of alcohol is well-known but trying to maintain the correct concentration of alcohol is much more difficult.  There are instruments that can measure the precise concentration but these are quite expensive (Mettler Toledo and the Anton Paar DMA 135n).
Since most museums have large collection and few staff to maintain them, they tend to have their own protocols to short-cut this otherwise lengthy process.  Most just top up the jars using a more concentrated level of alcohol (80%) and hoping that the overall concentration of each jar’s alcohol will end up around the 60-70% mark.
John Simmons, Ollie Crimmen and Andy Bentley will probably write something as they have had more experience in fish collections and dealing with fish oil contaminants as well.

With all good wishes, Simon.

Simon Moore MIScT, RSci, FLS, ACR
Conservator of Natural Sciences and Cutlery Historian, 



www.natural-history-conservation.com 




> On 29 Sep 2018, at 15:33, Katja Seltmann <seltmann at ccber.ucsb.edu> wrote:
> 
> We have just started caring for a small teaching collection of fish. The jars seem to be filled with alcohol, but I am assuming that the original specimens were preserved with formaldehyde. Many of the specimens need the fluid in the jars topped off, but I do not know what concentration of ethanol we should be using.
> 
> Does anyone have a protocol for their collection they would be willing to share?
> 
> Thank you,
> Katja
> 
> -- 
> 
> --
> Katja Seltmann, PhD
> Katherine Esau Director, Cheadle Center for Biodiversity & Ecological Restoration
> University of California, Santa Barbara (UCSB)
> Harder South, Rm 1011
> Santa Barbara, CA 93106
> cell: (859) 537-9309
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