Surprisingly but such job really exists in SUE «Vodokanal of St. Petersburg». Crawfishes serve for the analysis and monitoring of water. The technology developed by the St. Petersburg research center of environmental safety assumes control of a condition of water by means of measurement of frequency of heartbeat of crawfish. As it appeared these beings are the best indicators.
Process of monitoring doesn’t present any difficulties. The fiber-optical sensors are connected to the crawfishes’ armors. Sensors continuously register their heartbeat. If some dangerous substance suddenly appears water which is taken from Neva, crayfish will react in 1.5-2 minutes. Their heartbeat becomes frequent twice, and the stress index increases from zero up to several thousand. In a usual state the rhythm of heartbeat of crayfish makes 30-60 beats per minute. As soon as toxic substance gets to water, this indicator will sharply increase. After that people in laboratory will immediately gat the warning signal.
However, not all crayfish will be allowed to apply for such “job”. All applicants will be selected according to the following points:
- Crayfish has to be healthy and hardy. This criterion is checked during the catch. If crayfish actively resists, swings claws and a tail, then it passes the first stage of selection.
- Females aren’t allowed to work in such conditions. During incubation of caviar these individuals can worry for the reasons not connected with purity of water. Whereas, males react only to change of the environment and pass the second stage of selection.
- Crayfish has to be ready to continuous service within a year. In the habitat these beings fall into hibernation. During monitoring the break in 2-3 months isn’t expedient, but it is also not good to spend much time without dream too. Therefore after a year of service, crayfish are released back to Neva on pension.
Now you know that such heroes work for the benefit of all St. Petersburg’s citizens!