Sewage Pipe Waters Affect Colour Composition in Palaemon Shrimp from the Intertidal in the Canary Islands: A New Non-lethal Bioindicator of Anthropogenic Pollution

Abstract

Marine pollution through anthropic outfalls like sewage pipes is a growing concern since point-source pollution can affect many organisms. Investigating pollutant concentrations in organisms usually requires sacrificing the organisms, but here we propose a new method to infer anthropic pollution in the intertidal by measuring colour levels in Palaemon elegans rockpool shrimp. We took pictures of live shrimp from pools near sewage pipes and control zones in three of the Canary Islands (Gran Canaria, Lanzarote and Tenerife), and measured their RGB (red, green and blue) abdominal colour composition. We then statistically compared colours from the control zone and sewage pipe and between islands. We found a clear differentiation in colour composition between the control zone and areas with a sewage pipe. Our results supported the hypothesis that pollution affects colouration in these invertebrates. We, therefore, suggest the use of darker colourations in P. elegans as a bioindicator of anthropic pollution, a first sign that should spur more in-depth studies in the affected area. This methodology is pollutant unspecific but non-extractive, so we propose its use as a citizen science tool to inform scientists and technicians of possible illegal and/or untreated wastewater that could affect intertidal biota.

Metal Concentration in Palaemon elegans along the Coastal Areas of Gran Canaria (Canary Islands): Potential Bioindicator of Pollution

“…Marine pollution arises from the infiltration of toxic substances and waste into oceans, leading to various adverse effects on the health of marine organisms, human communities relying on them for sustenance, and various adverse effects on overall environment. These harmful substances stem from a variety of sources, including agriculture, industry, sewage discharge, shipping activities, atmospheric debris, oil extraction, and fishing operations [13][14][15][16][17][18][19]. The repercussions of marine pollution are extensive, encompassing a range of issues such as habitat destruction, alterations in the oceans' chemical composition, depletion of wildlife populations, and contamination of food sources.…”