Development of a shark health matrix using metabolomics coupled with metagenomics

The skin of any aquatic animal serves as the direct interface between the organism and their environment, including available nutrients and abiotic conditions. Shark skin, which is comprised of dermal denticles above a mucus layer, hosts a diverse array of symbiotic microorganisms including bacteria, archaea and viruses. These microbiotas collectively make up the sharks’ microbiome. The small molecules these microorganisms produce are identified via high resolution mass spectrometry-based metabolomics.

Coupling metabolomics with metagenomic analyses provides robust taxonomic and functional community profiles of shark skin microbiomes. As anthropogenic forces cause shark populations to decline worldwide, conservational efforts aimed at evaluating shark fitness are increasingly necessary. Metabolic functions of shark-skin microbiomes are instrumental for the construction of a health matrix and aquarium populations may serve as indices for healthy microbiota community states. The San Diego Birch Aquarium at Scripps houses several species of Elasmobranches, including leopard, horn, and swell sharks and we began annual veterinary exams in the summer of 2018 to evaluate the health of these specific kelp-tank inhabitants. Here we aim to identify a core microbial composition and functional metabolites of the three shark species and compare with shark health indicators, such as blood counts, to describe the relationship between microbiome and shark health.

Preliminary results of core blood metabolites show a distinct difference between the three species of sharks with 34 unique metabolic features for swell sharks, 27 for horn sharks and 62 for leopard. Interestingly, there are over 2,000 metabolic features that are similar to all species. These metabolites will be identified using tandem mass spectrometry and tracked over time during regularly veterinary checks. In addition, these metabolites will be compared to those found in the skin microbiome to develop a less invasive method of tracking shark health.