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Publication Extract

The following extract is the Background information, page 95, from the BES Publication, "Brine Shrimp Ecology"

Handling Brine Shrimps in the Classroom

Some practical tips and ethical issues

Brine shrimps are very delicate animals and one must take care not to harm them when they are handled. Refer to the student work sheet on Handling and observing brine shrimps (page 6).

Firstly, brine shrimps should always be in water of at least 10 g per litre salt (preferably 35 g per litre). Do not use fresh water or tap water - although they will survive for some days in these media. When in the salt solution and supported by the water they are resilient and quite hardy within their aquatic environment. For example, they are not harmed at all by gentle stirring of the environment or rolling of the culture bottle (or bottle ecosystem) to clean 'the windows'.

Teachers should be careful to engender a good ethical attitude towards these animals and not a totally instrumental one. Although they are simple organisms that may not 'suffer' in the same way as higher animals, they still demand respect. This is particularly true when experiments are set up to establish the parameters favoured by the shrimps, e.g. temperature preferences and pollution tolerance. Animals should go back into the holding tank after being examined. This engenders the ethics that are commensurate with field work where pond animals are returned to their habitat after observations have been made.

The best way to catch shrimps from a tank is to go fishing for them with a fine sieve. Shrimps may be lifted out easily for transfer to experimental vessels (using a tea-strainer is ideal). They should be lowered into a small beaker and allowed to swim free. Don't let them dry up in the sieve. A coarse sieve of 2-3 mm mesh will catch only adults.

If you pour water containing shrimps through a cotton pocket handkerchief that is supported by a funnel, it will separate all the shrimps, larvae and eggs from the water. However as most of the algae will pass through a cotton handkerchief this is useful if you are wanting to culture the algae alone.

To pick up a shrimp from the water use a pipette. The most suitable pipettes are made of soft plastic with inside bore of at least 5 mm. Cut off the pointed end of the pipette so as to make a tube that is wide enough for the adults to enter when sucked. This should have a bore of 3-5 mm. When sucked up the shrimp will not be distressed and will not escape from the water. The animals are robust in water, but of course are not to be handled out of this medium.

To put a shrimp on a slide take a clean glass slide and gently rub it dry and shiny. Put just a few drops of water with the shrimp onto the slide. Suck up any extra water so that the shrimp is confined in a blob of water. Remember that water has a high surface tension. Shrimps may be restrained in a few drops of water by surface tension. Glassware that has detergent on it will therefore not behave in this way. The water must not dry up, so add just one drop of water every minute or two. A sheet of graph paper, with millimetre squares, photocopied onto a single overhead transparency acetate sheet, will provide a 'non-wettable' metricated surface ideal for shrimp observations.

If you place this slide or acetate sheet beneath a hand-lens (e.g. x 10) or under a low power microscope (e.g. x 40) you can observe much detail. Always release the animals back into their tank after about five minutes. Small shrimps, eggs and naupliar larvae may be suspended in a hanging drop on a cover-slide. Observation in the hanging drop may be made at up to 100x magnification, when this is placed above a clear plastic film can lid. Sustained observation here is possible without great evaporation of water from the hanging droplet.

Copyright: BES Brine Shrimp Ecology Project: Homerton College Cambridge

Copyright 2007 British Ecological Society. All Rights Reserved