Asking about the scientifically valid method for the long term preservation of Marine Specimens in the museum?
Dear Scientists/Researchers
I want to do some field and collect some marine fishes (small and medium sizes) and want to preserve them as museum specimens.
At this moment some guys suggest me to collect fishes then fixed in 10% formaldehyde, bring to laboratory, identify and preservation with 70% etahyl alcohol solution (https://www.nps.gov/museum/publications/conserveogram/11-03.pdf) and some cases with 37% formaldehyde solution (https://research.amnh.org/vz/ichthyology/congo/other05.html). But I am afraid and don't know is these ways are scientifically valid or not for the long term preservation as museum specimens.
So, which method/methods are best and scientifically valid for the long term preservation of marine fishers as specimens in the museum? Please seeking suggestions/ related peer-reviewed published articles.
I want to do some field and collect some marine fishes (small and medium sizes) and want to preserve them as museum specimens. Asking about the scientifically valid method for the long term preservation of Marine Specimens in the museum?
which method/methods are best and scientifically valid for the long term preservation of marine fishers as specimens in the museum? Please seeking suggestions/ related peer-reviewed published articles.
THE WESTERN AUSTRALIAN MUSEUM also following preservation of the fish sample with formaldehyde and store the sample with 70% methylated ethanol. It has a collection of 180,000 specimens of fishes from around 5000 species. Thanks
Thanks a lot Md. Masum Billah for your invaluable information. Would you can please provide a few related peer-reviewed published articles (if possible).
Dear Colleague,
The opinions that you already received are valid methods of preservation. However, I would like to remind you that formaldehyde should be handled carefully because is toxic. I have had excellent results injecting small quantities of solution of formaldehyde 3% in the epaxial muscles and also in the "abdominal" cavity of each specimen because it ensures the process of preservation (especially of the stomach content). After that is done, the fish should be covered with ethanol 70% or methyl ethanol. You should make sure that the fish is always completely covered with ethanol, other way the specimens will dry out. This means that you should check frequently the level of the ethanol covering the specimens.
With my best wishes.
Thanks a lot Gloria Arratia for your invaluable information. I have already found some better results when large specimen were injected by 10% formalin and then preserved in 10% formalin solution like small specimen. Any way, would you please provide a few related peer-reviewed published articles (if possible).
I agree with Masum and Gloria.
Best to store fishes over long times is in 70% ethanol. Nevertheless, if you transfer (especially small) fish in ethanol you should pass it through an ascending alcohol series (40% for 8-9 hours, 60% 12 hours, best over night and subsequently into 70%) to prevent too fast exchange of body liquid with the ethanol. Placing the fish directly into 70% ethanol could create too fast shrinking resulting in shrivels. Additionally, the alcohol will be diluted by the body liquids and you have to transfer the fish a second time into 70% alcohol.
If you prefer to store the fish in formaldehyde I also would like to point to the fact that this preservation liquid is highly toxic and cancerogenic. Handle with care. Nevertheless, if you still plan to stick with this method, you have to use buffered formaldehyde. Otherwise the ossified structures will be damaged or even destroyed over time. Additionally, 10% formaldehyde is a too high concentration. This will make the fish stiff, the fins probably immovable and it will be hard to work with such material (taking morphometrics and eristics). 5-6% for preservation is enough. But once again, I strongly recommend not to use formaldehyde.
Best wishes, Harald
Dear Colleagues,
I agree that the use of formaldehyde to preserve complete specimens should be avoided as much as possible, independently of the size of the specimens. What it is important to establish from the start is what is/are the goal(s) of this collection. If the collection is planned for a demonstration of fish biodiversity in the region, including fishes of different sizes, then ethanol 70% could be an appropriate choice. If the fishes are large (e.g., over 30 cm SL) and larger, injection of small amount of formaldehyde 3% in the body muscles and cavity previous place the fish in ethanol (or methyl ethanol) is also a good choice. However, if the collection is planned for different kinds of research, then, this should be considered in advance. In all cases, ethanol 70% will not have additional long-term effects, as the formaldehyde that decalcifies bony structures over certain period of time.
At the present time and following safety regulations, formaldehyde is not welcome in most laboratories and collections. However, if you have to use it, you should use buffered formaldehyde, as suggested by Colleague Harald, but in small quantity and low concentration. Still, some institutions worldwide keep using formaldehyde because it is cheaper than ethanol or methyl ethanol, but the risks should not be ignored.
I suggest that you study very carefully your goals and plan and act accordingly. Overall, do not overlook the budget that you will need year after year for a long term collection. Plan all what you need, not only ethanol, but also glasses, cabinets, labels, etc.
With my best wishes.
Well, please find a relevant published paper for your kind concern
Chakraborty, A., M. Sakai, and Y. Iwatsuki. "Museum fish specimens and molecular taxonomy: A comparative study on DNA extraction protocols and preservation techniques." Journal of Applied Ichthyology 22.2 (2006): 160-166.
http://onlinelibrary.wiley.com/doi/10.1111/j.1439-0426.2006.00718.x/epdf
I agree that specimens are preserved in 10% formaldehyde in the field. If the condition is permitted, specimens in the 10% formaldehyde should be frozen, in order to remain intergrate morphological characters of small fish.
Dear Harald
Thanks a lot for your invaluable information mentioned above. Would you can please provide a few related published articles (if possible) whose I can use as references.
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