Specimen jars containing fish

Physical Samples

NTL’s zooplankton, phytoplankton, fish scale, dendy and pelagic tow sample archive:

University of Wisconsin Zoological Museum:
Noland Zoology Building, 250 N. Mills St., Madison WI
Contact: Laura Monahan and Emily Halverson

NTL’s microbial sample archive:

5525 Microbial Sciences Building, 1550 Linden Drive, Madison WI
Contact: Trina McMahon

Description of Collections:

  • Zooplankton are wet samples, in formalin or ethanol, in 2 to 8 oz. jars in half-sized records boxes on open shelving.
  • Phytoplankton have traditionally been stored wet but, a conversion to microscope slide format (some pooled samples remain in wet storage) has begun. The wet samples are stored on open shelving; the slide samples are stored in one of the metal “Tensco” cabinets.
  • Fish scales are stored in small envelopes, organized by lake, year, and species in card catalog drawers.
  • Dendys (invertebrates collected with a Hester-Dendy sampler) are wet samples, preserved in ethanol, in vials and jars. The samples are organized in records boxes on open shelving.
    • Northern lakes only
  • Pelagic invertebrate tows (vertical night tows) are wet samples in ethanol stored on open shelving.
    • Northern lakes only
  • Macrophyte samples are dried and stored in boxes on open shelving.
  • Microbial samples are stored on 0.2 um filters that were used to capture planktonic biomass from whole water at the time of sampling. The filters are stored at -80C inside 2.0 mL screw-cap tubes.

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Loan Procedures - General

Get approval use archived samples from NTL (see general contact information).

  • Provide a written description (informal email format is ok) of what samples you need and how you will use them.  Include an estimate of when the samples will be returned.
  • NTL will notify Laura Halverson, the Zoological Museum (UWZM) registrar, that you have been approved for a loan.

Go to the UWZM to get the samples and paperwork.

  • Laura will admit you to the collection and provide a Loan Form which will detail the samples you are removing. Keep the Loan Form with the samples. Additional forms may be needed for some types of samples (detailed below).
  • Generally, only half of the samples per sampling event, lake, and, if applicable, species, may be taken out of the museum at any one time. The other half may be obtain upon return of the first set of samples.
  • Destructive sample is only permissable up to point of minimal sample still available.

The samples are to be used only by you. They must be returned to the museum before going to anyone else needing to use them.

Return samples and paperwork to the UWZM when you are finished with them.

  • Contact Laura Halverson for admittance to the museum to return the samples and paperwork, and have the loan return checked in. Leave the samples on the desk; do not return them to the collection boxes.
  • Notify NTL that the loan has been returned
  • The Museum Committee will return the samples to the proper boxes in the collection.

Phytoplankton Slides

See the General Procedure section above for instructions on getting approved for a loan, and taking and returning samples.

Remove only one of the three slides for any lake/date. Requests to use more than one slide from a set will be evaluated on a case by case basis, however we will not allow all three slides of a set to be out of the collection at the same time.

Zooplankton Samples

See the General Procedure section for instructions on getting approved for a loan, and taking and returning samples.


Samples collected before 2001 are preserved in formalin. Formalin is a known carcinogen. These samples should be handled in a fume hood or with other appropriate ventilation to avoid inhalation of formalin fumes. Skin contact should be avoided as well.

Get an introduction to Volume by Weight forms from Pam Montz or Corinna Gries.

  • You will need this additional form, the Volume by Weight form, for zooplankton samples. Remove the forms needed from the binders and keep them with the samples. Make sure you understand how to record information on the form before using the samples.

Bring each sample up to the correct volume before using it.

  • Weigh the sample, including lid.
  • Add deionized water (samples before 2001) or 95%EtOH (samples from 2001 to present) to the jar to bring it up to the last weight recorded on the Volume by Weight form. This process corrects for volume lost to evaporation during storage.
  • If the sample weight is within 1 gram of the last recorded weight, you do not have to add liquid.
  • If the sample weighs more than last weight recorded on the V by Wt form, evaporate it in a fume hood until it is the correct weight.

Maintain the integrity of sample density. VERY IMPORTANT!

  • Mix the sample gently and thoroughly by tipping from side to side before subsampling. Remove your subsample from the jar immediately after mixing. Use as little of the sample as possible.
  • Do not return the subsample to the jar after you are done with it.

When you are finished with the sample.

  • Mark the new liquid level on the outside of the jar with a Sharpie permanent marker.
  • Weigh the sample and record the new weight on the Volume by Weight form along with your initials and date in the appropriate columns. Tighten lids well when done!

Fish Scales

See the General Procedure section above for instructions on getting approved for a loan, and taking and returning samples.

Scale Use Requirements

  • If you will not return the scales to the envelopes (destructive sampling), you are allowed to take only one scale from any envelope and must leave at least three scales in the envelope.
  • Destructive sampling needs special permission and may be only performed until a minimum of 2-3 scales is left per sample.

Dendy Samples

See the General Procedure section above for instructions on getting approved for a loan, and taking and returning samples.

If sampling destructively, remove individuals from only one of the three replicates from any site. When returning samples, include a form noting which sample replicates were subsampled, and indicating identity and number of individuals removed.