Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2022

Epidermal microbiomes of leopard sharks (Triakis semifasciata) are consistent across captive and wild environments (#135)

Asha Z Goodman 1 , Bhavya Papudeshi 2 , Doane P Michael 2 , Mora F Maria 1 , Kerr Emma 2 , Elizabeth A Dinsdale 2
  1. San Diego State University, San Diego, CA, United States
  2. Flinders University, Adelaide, South Australia

Characterizations of sharks-microbe systems in wild environments have outlined patterns of species-specific microbiomes1; however, whether captivity affects these trends has yet to be determined. We used high-throughput shotgun sequencing2 to assess the epidermal microbiome belonging to leopard sharks (Triakis semifasciata) in captive (Birch Aquarium, La Jolla California born and held permanently in captivity, n = 4), semi-captive (held in captivity for <1 year in duration and scheduled for release; Scripps Institute of Oceanography, California, n = 4) and wild environments (Moss Landing n = 6, and La Jolla, California, n = 8). Here we report captive environments do not drive epidermal microbiome compositions of T. semifasciata to significantly diverge from wild counterparts (PERMANOVA Family level, Pseudo-F df =2, 27 =, P(perm) > 0.1); Genus level, Pseudo-F df =2, 27 =, P(perm) > 0.1) as life-long captive sharks maintain a species-specific epidermal microbiome resembling those associated with semi-captive and wild populations. Major taxonomic composition shifts were observed were inverse changes of top taxonomic contributors across captive duration, specifically an increase of Pseudoalteromonadaceae and consequent decrease of Pseudomonadaceae relative abundance as T. semifasciata increased duration in captive conditions. Moreover, we show captivity did not lead to significant losses in microbial α-diversity of shark epidermal communities. Finally, we present a novel association between T. semifasciata and the Muricauda genus as Metagenomes associated genomes revealed a consistent relationship across captive, semi-captive, and wild populations. Since changes in microbial communities is often associated with poor health outcomes3,4, our report illustrates that epidermally-associated microbes belonging to T. semifasciata are not suffering detrimental impacts from long or short-term captivity. Therefore, conservation programs which house sharks in aquariums are providing a healthy environment for the organisms on display. Our findings also expand on current understanding of shark epidermal microbiomes5, explore the effects of ecologically different scenarios on benthic shark microbe associations, and highlight novel associations that are consistent across captive gradients.

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