[Nhcoll-l] [MOGELIJK SPAM ! *****] Preserve fish specimens

[Dirk Neumann]

Dear Maxine,

it is very difficult to preserve the colour of living fish; even if you follow Dries' recommendation and recipe, the colour in the preserved specimen will not be the same as in the living one. If the colour carries important information, e.g. to characterise or determine the species, it would be best to photograph the still living fish in a small photo tank, because as soon as the fish is dead, the colour usually fade within seconds or minutes.

High resolution images allow to zoom in an even can give nuances of different melanophores. If you need this colour information for your research, you should make sure that you take the photos in a standardised setting.

The SPNHC Wiki pages offer further infromation that might be useful https://spnhc.biowikifarm.net/wiki/Digital_Imaging, at the end there are links that direct you to specific sites/PDFs that provide further details on the setup.

Hope this helps
Dirk



Am 18.09.2022 um 13:13 schrieb a.j.van_dam at lumc.nl<mailto:a.j.van_dam at lumc.nl>:

Dear Maxine,

You could indeed do some experiments with glycerol to see if it would better preserve the colours. To avoid shrinkage, it is important that after fixation you transfer to glycerol by increasing concentration steps (e.g. 30-50-70%). A concentration between 65-70% should be sufficient to keep them well preserved and prevent fungal growth, provided that the RH in the room where the jars are kept does not exceed 70%.

You might also want to embed them after a complete glycerol transfer (30-50-70-80-90-95-100-100%) in polyester resin. Before embedding them, you should get most of the glycerol off the surface by using paper or cotton towels and cotton swabs.

Just before placing them in the unhardened polyester (3 layers: ground, middle embedding layer, and top layer), dip the specimens for about a minute or so in acetone and then cellosolve. This ensures that the polyester will bind to the skin of the fish.

Kind regards,

Dries


Andries J. van Dam<http://www.linkedin.com/in/andriesvandam> | curator-conservator

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________________________________
Van: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu><mailto:nhcoll-l-bounces at mailman.yale.edu> namens Maxine C <cutraccimaxine at gmail.com><mailto:cutraccimaxine at gmail.com>
Verzonden: vrijdag 16 september 2022 05:40:43
Aan: nhcoll-l at mailman.yale.edu<mailto:nhcoll-l at mailman.yale.edu>
Onderwerp: [MOGELIJK SPAM ! *****] [Nhcoll-l] Preserve fish specimens

Hi all,

I'm working on a research project at the University of Hong Kong on fish biodiversity. We would like to preserve very small cryptobenthic fish species ( 5 - 10 mm in length).
In the past, I've used formalin and ethanol 70% but I'd like to preserve the coloration.

Any advice? Would resin work?

Regards,

Maxine



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Dirk Neumann
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--
Stiftung Leibniz-Institut zur Analyse des Biodiversitätswandels
Postanschrift: Adenauerallee 127, 53113 Bonn, Germany

Stiftung des öffentlichen Rechts;
Generaldirektion: Prof. Dr. Bernhard Misof (Generaldirektor), Adrian Grüter (Kaufm. Geschäftsführer)
Sitz der Stiftung: Adenauerallee 160 in Bonn
Vorsitzender des Stiftungsrates: Dr. Michael Wappelhorst
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