COUGHING SCALLOPS: POTENTIAL INDICATOR FOR WATER POLLUTION

Bivalve mollusks or scallops are extremely important both economically and ecologically. Because the geochemical composition of the shell carbonate varies with variations in environmental parameters including temperature, salinity, nutrient content, and primary productivity, their shells are natural repositories of paleo-climate information.  They are organic repositories of environmental data that can be extracted from their outer layer. Stressors in the surrounding environment have an impact on the size and development of growth increments marked by striae (small com-marginal growth ridges on valve surfaces). Although the mechanisms underlying the relationship between striae deposition and shell growth in response to environmental differences are not well understood, they are probably related to the animal's valve-movement behavior. 

Coughing allows scallops to release water and excrement from their inner chambers. A sharp cracking sound is produced by the friction between the mollusk's two valves, and as the valves shut, there is a long puffing sound. According to biologists, these coughs may act as a warning sign for declining water quality. Additionally, their acoustic properties set them apart from other known benthic animals(species associated with the bottom of water bodies). These findings suggest that passive acoustics can be used in situ to monitor scallop valve motions. Thus underline that long-term monitoring of a scallop species' behavior and its responses to growth-affecting environmental changes is likely to benefit greatly from the use of acoustic recording, which is a potent and non-intrusive technique.  the sound produced by scallop valve movements can be identified and tracked by passive acoustics is supported by the results of this study. Physiological processes are linked to valve-movement behaviors, such as the "cough," a rapid valve adduction linked to the expulsion of water, feces, and other substances from the mantle cavity. These behaviors vary depending on environmental fluxes that have a direct impact on striae deposition and, consequently, shell growth. Bivalve movement has been recorded in situ using animal-attached Hall sensors and accelerometers, but their deployment time is constrained and the animals must be handled in order to instrument them. This work provides an example of a novel passive acoustics-based long-term (month-long) monitoring method.

Acoustic monitoring is a powerful technique for recording animal behavior because of the exceptional properties of sound waves in water and the fact that many marine organisms produce sounds, either unintentionally every time they vibrate or intentionally for communication or remote sensing.Examination of the possibility of tracking the movement of pectinid bivalves using passive acoustics. Investigating if P. maximus valve movement, namely coughing, generates sound that can be picked up by a hydrophone, a passive acoustic sensor. In order to assess the efficacy of cough detection under varying ambient noise levels and thus correlate the movement of the scallop valve with acoustic recordings to define coughing sounds in terms of acoustic metrics. Lastly, there is a discussion on the long-term non-intrusive monitoring of pectinid bivalve behavior using passive acoustic sensors.

Reference:

1.https://scitechdaily.com/coughing-scallops-early-warning-system-for-worsening-water-quality/

2. “Hydrophone detects cracking sounds: Non-intrusive monitoring of bivalve movement” by Lucia Di Iorio, Cédric Gervaise, Virginie Jaud, Anthony A. Robson and Laurent Chauvau, 30 November 2012, Journal of Experimental Marine Biology and Ecology.

Image source:

https://www.morningagclips.com/wp-content/uploads/2019/07/scallops.jpg