[Nhcoll-l] Preservation of a fish collection

[Bentley, Andrew Charles]

Hi Katja

Yes, traditionally fish specimens are fixed in 3.4% formalin and then transferred to 70% ethanol for long term preservation.  When topping off is necessary we usually use two criteria to determine what to top off with.  If the jar is under half full we usually discard all old preservative and fill with fresh 70%.  If the jar is more than 50% full then we simply top off with fresh 70% ethanol.  If alcohol is particularly oily or discolored we will also completely change fluid – especially in a teaching collection where specimens need to be viewed more often.  Fort research specimens we will not change fluid unless absolutely necessary to avoid further leaching of oils, lipids and color out of the specimens.

The important factor to consider when mixing your 70% ethanol is to ensure that you keep the acidity down by mixing with deionized water or tap water (if your tap water is alkaline enough).  A simple alkalinity test will determine whether tap water is sufficient.  Thorough mixing of the alcohol and water is also necessary to ensure an even mixture.  We use an air bubbler for about an hour to ensure thorough mixing of the fluid before use.

Hope that helps.  Happy to answer any further more specific questions.

Andy
    A  :             A  :             A  :
 }<(((_°>.,.,.,.}<(((_°>.,.,.,.}<)))_°>
    V                V                V
Andy Bentley
Ichthyology Collection Manager
University of Kansas
Biodiversity Institute
Dyche Hall
1345 Jayhawk Boulevard<x-apple-data-detectors://9>
Lawrence, KS, 66045-7561<x-apple-data-detectors://9>
USA<x-apple-data-detectors://9>

Tel: (785) 864-3863<tel:%28785%29%20864-3863>
Fax: (785) 864-5335<tel:%28785%29%20864-5335>
Email: abentley at ku.edu<mailto:abentley at ku.edu>
http://ichthyology.biodiversity.ku.edu<http://ichthyology.biodiversity.ku.edu/>
    A  :             A  :             A  :
 }<(((_°>.,.,.,.}<(((_°>.,.,.,.}<)))_°>
    V                V                V

From: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> On Behalf Of Simon Moore
Sent: Sunday, September 30, 2018 4:18 AM
To: Katja Seltmann <seltmann at ccber.ucsb.edu>
Cc: nhcoll-l at mailman.yale.edu
Subject: Re: [Nhcoll-l] Preservation of a fish collection

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,

[cid:image001.png at 01D4595E.71D13180]

www.natural-history-conservation.com<http://www.natural-history-conservation.com>




On 29 Sep 2018, at 15:33, Katja Seltmann <seltmann at ccber.ucsb.edu<mailto: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
http://codex.begoniasociety.org<http://codex.begoniasociety.org/>
_______________________________________________
Nhcoll-l mailing list
Nhcoll-l at mailman.yale.edu<mailto:Nhcoll-l at mailman.yale.edu>
https://mailman.yale.edu/mailman/listinfo/nhcoll-l

_______________________________________________
NHCOLL-L is brought to you by the Society for the Preservation of
Natural History Collections (SPNHC), an international society whose
mission is to improve the preservation, conservation and management of
natural history collections to ensure their continuing value to
society. See http://www.spnhc.org for membership information.
Advertising on NH-COLL-L is inappropriate.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.yale.edu/pipermail/nhcoll-l/attachments/20181001/45aee730/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.png
Type: image/png
Size: 179017 bytes
Desc: image001.png
URL: <http://mailman.yale.edu/pipermail/nhcoll-l/attachments/20181001/45aee730/attachment.png>