Investigating diversity of pathogenic microbes in commercial bait trade water.

Christopher L. Jerde,Andrew R. Mahon,Lucas R. Nathan,Dean J. Horton,Deric R. Learman

doi:10.7717/peerj.5468

Christopher L. Jerde, Andrew R. Mahon + Show 3 more

Open Access

https://doi.org/10.7717/peerj.5468

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Abstract

The recreational bait trade is a potential pathway for pathogen introduction and spread when anglers dump bait shop sourced water into aquatic systems. Despite this possibility, and previous recognition of the importance of the bait trade in the spread of aquatic invasive species (AIS), to date there has been no region wide survey documenting pathogens in retail bait shops. In this study, we analyzed 96 environmental DNA samples from retail bait shops around the Great Lakes region to identify pathogens, targeting the V4 hypervariable region of the 16S rRNA gene. Additionally, we used samples from one site in Lake Michigan as a comparison to pathogen diversity and abundance in natural aquatic systems. Our results identified nine different groups of pathogens in the bait shop samples, including those that pose risks to both humans and fish species. Compared to wild sourced samples, the bait shops had higher relative abundance and greater taxonomic diversity. These findings suggest that the bait trade represents a potentially important pathway that could introduce and spread pathogens throughout the Great Lakes region. Improving pathogen screening and angler outreach should be used in combination to aid in preventing the future spread of high risk pathogens.

Highlights

With over 30 million anglers in the United States and Canada, and with many of them using live bait in the form small fish (USDI, 2011; DFO, 2012), there is a significant risk of invasive species introduction and spread through the commercial bait trade vector (Drake & Mandrak, 2014)
Our goal was to identify pathogenic species present in the samples, compare the diversity and abudance of bait shop sourced pathogens to Great Lake sourced pathogens, and evaluate the potential threat of unique, bait sourced pathogens being spread in the Laurentian Great Lakes in a manner similar to that documented for invasive species
The role bait water plays in pathogen transmission is unclear

Summary

Introduction

With over 30 million anglers in the United States and Canada, and with many of them using live bait in the form small fish (USDI, 2011; DFO , 2012), there is a significant risk of invasive species introduction and spread through the commercial bait trade vector (Drake & Mandrak, 2014). This is alarming when commercial bait retailers are contaminated with invasive fish, such as Goldfish (Carassius auratus), Round Goby (Neogobius melanostomus), Eurasian Rudd (Scardinius erythrophthalmus), and Silver Carp (Hypophthalmichthys molitrix) (Nathan et al, 2015). This raises the question, what pathogens are found in the bait bucket water?

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