Continuous Noninvasive Measuring of Crayfish Cardiac and Behavioral Activities

Summary

This article presents a noninvasive biomonitoring system for the continuous recording and analyses of crayfish cardiac and locomotor activities. This system consists of a near-infrared optical sensor, a video-tracking module, and software for evaluating crayfish heartbeats that reflects its physiological condition and characterizes crayfish behavior during heartbeat fluctuations.

Abstract

A crayfish is a pivotal aquatic organism that serves both as a practical biological model for behavioral and physiological studies of invertebrates and as a useful biological indicator of water quality. Even though crayfish cannot directly specify the substances that cause water quality deterioration, they can immediately (within a few seconds) warn humans of water quality deterioration via acute changes in their cardiac and behavioral activities.

In this study, we present a noninvasive method that is simple enough to be implemented under various conditions due to a combination of simplicity and reliability in one model.

This approach, in which the biological organisms are implemented into environmental evaluation processes, provides a reliable and timely alarm for warning of and preventing acute water deterioration in an ambient environment. Therefore, this noninvasive system based on crayfish physiological and ethological parameter recordings was investigated for the detection of changes in an aquatic environment. This system is now applied at a local brewery for controlling quality of the water used for beverage production, but it can be used at any water treatment and supply facility for continuous, real-time water quality evaluation and for regular laboratory investigations of crayfish cardiac physiology and behavior.

Introduction

The subject of aquatic organisms' applications, both as model organisms for various laboratory investigations^1,2 and as tools for monitoring industrial and natural/environmental water quality^3,4, appears to be well studied. Nevertheless, this topic is still of noteworthy interest for humans, irrespective of whether they belong to the scientific community or to other occupations. In spite of the existence of a number of advanced methods for monitoring certain parameters (so-called "biomarkers")^5,

Protocol

1. Crayfish Selection

1. In order to successfully apply the current approach to crayfish, select the respective adult specimens with sufficient carapace sizes (which is a carapace length of at least 30 mm) for sensor attachment, visually examine it for the absence of diseases, and check whether it lifts both chelae when it is touched. The above-mentioned parameters indicate an eligible state of crayfish health.
   NOTE: If several crayfish are expected to be used in the trial and are exposed.......

Discussion

It has been widely suggested that the measurement of certain physiological parameters (such as heart or ventilation rate or both) is a more reliable method for recording crayfish reactions than the evaluation of behavioral responses that do not always occur immediately¹¹. However, it is evident that the most efficient approach for assessing real crayfish reactions to environmental changes is the combination of cardiac activity and behavior recordings since that makes it possible to see the reason(.......

Materials

Name	Company	Catalog Number	Comments
IR LED diode	KINGBRIGHT ELECTRONIC	KP-3216F3C
Phototransistor	EVERLIGHT	ELPT15-21C
Resistor	ROYAL OHM	0805S8J0201T5E
Resistor	ROYAL OHM	0805S8F2200T5E
Capacitor	KEMET	C0805C334K5RACTU
Cable	TECHNOKABEL	FTP KAT.5E 4X2X0,14C
Connector	HARTING	21348100380005
Connector	HARTING	21348000380005
Dielectric gel	KRAYDEN	Sylgard 535
Analogue-to-digital convertor	TEDIA	UDAQ-1416CA
Glue	KUPSITO.SK	7338723044
Kinect video camera	ABCSTORE.CZ	GT3-00002
Analysis software	University of South Bohemia in Ceske Budejovice, Faculty of Fisheries and Protection of Waters, Institute of Complex Systems		Link to the software: www.frov.jcu.cz/crayfishmonitoring User name: frov Password: CF2018