Abstract
Cultured oysters are one of the most valuable marine industries globally, however, predation of oysters during the grow out phase by rays can lead to large crop losses. Ray predation is usually mitigated by building large, netted structures around or over oyster racks, but these can fail, are costly to maintain, and can lead to parasitic flatworms that lower oyster value. Here we examine the potential of using non-lethal deterrents including magnets and electric deterrents to reduce oyster predation from six species of rays. A preliminary field experiment compared the deterrent potential of ferrite, rare earth (neodymium) and an electric deterrent, and found only the electric deterrent reliably prevented rays from feeding on baits (100% of interactions with rays). A larger experiment conducted amongst oyster farms found the electric deterrent was very effective (85.48% across all interactions) at reducing feeding interactions relative to a control. These results highlight that electric deterrents could be developed to reduce oyster predation by rays without the limitations of more traditional measures. Furthermore, permanent magnets were considerably less effective at deterring batoid interactions than electric deterrents, and would not be viable for these applications.
| Original language | English |
|---|---|
| Article number | 102873 |
| Pages (from-to) | 1-8 |
| Number of pages | 8 |
| Journal | Regional Studies in Marine Science |
| Volume | 61 |
| DOIs | |
| Publication status | Published - Jul 2023 |
| Externally published | Yes |
Bibliographical note
Funding Information:This work was funded by an industry-matched funding grant from the University of Newcastle and Graham Barclay oysters . Many thanks to the volunteers who assisted in the fieldwork for this project, including Molly Grew, Finlay Johnson, and Harrison Smith.
