Remotely operated vehicles (ROVs), like any machine or equipment used in marine or freshwater applications, present a potential risk for the transmission of invasive species. If not properly cleaned and treated, they may introduce novel species into new regions.
Our friends and colleagues have established a set of five guidelines to reduce the risk of marine invasive species introduction for ROV operators. We encourage ROV operators to follow these guidelines when traveling between ecosystems and deploying underwater drones in new areas. A comprehensive discussion of these guidelines can be found in their paper: Robots as Vectors for Marine Invasions: Best Practices for Minimizing Transmission of Invasive Species Via Observation-Class ROVs.
Step 1: Awareness
What you don’t know can really hurt. It’s vitally important to the mitigation and prevention of invasive species to be aware of the challenges, risks, and established practices in the area in which you plan to operate.
Learn about species invasion in general and look up any specific invasive species issues in the are that you are diving. Good resources for this can be the USDA website or state/local authority websites. As an example, check out these guidelines for Lake Tahoe.
Invasive species can be animals, plants, or microbes. Tiny larvae can be especially pernicious, resilient, and hard to see. Clearly we’re not talking about Asian carp hitching a ride on your Trident Underwater Drone, but the little things you might not be aware of.
Invasive Species: What Everyone Needs to Know by Daniel Simberloff is a great, accessible introduction to species invasion.
Step 2: Visual Inspection
Prior to any deployment, ROVs should be inspected to determine whether any observable biological material is present on the vehicle.
Pay extra attention to the o-ring seals, where tiny grains can become lodged, around the thrusters where sea grass and other filamentous organic matter can become entangled, and inside motor bells where material is hard to detect. Check behind service panels, removable bumpers, or any area where water can collect.
Perform the same visual inspection after each dive, returning any organic matter to its place of origin.
Inspect shoes, clothing, and any other gear to confirm that no organic material will be transmitted between sites.
Step 3: Freshwater Soak
Operators should soak ROVs in freshwater for 24 hours prior to transport between different geographic regions.
Rinse ROVs in clean freshwater following each dive. This will help remove salt and minimize corrosion of critical components as well as protect against invasive species.
Freshwater is lethal to many marine species, including microscopic organisms that cannot be detected during visual inspection.
Don't transport the water used for rinsing between sites.
Having a fun dive in a pool or freshwater tank is a great way to ensure a thorough rinse.
Step 4: Bleach Soak
ROVs should be thoroughly washed using a weak bleach solution or other readily available sanitizing agent.
This will kill many microbial and viral vectors that could be transported between sites.
Putting your ROV in a dilute bleach solution (7.75 mL household bleach per liter of water) for up to 15 minutes will not damage o-rings or other delicate components.
Many specific sites such as reservoirs and water treatment facilities have their own prescribed regimens for decontamination that should be followed.
Step 5: Dry Off
Using a clean towel or air drying the ROV after the soak will help keep the ROV’s motors and other components from gathering corrosion or rust during long transportation or storage. This will also assist in making sure there are no pockets of moisture or remaining areas of water trapped in your ROV that could house invasives.
Step 6: Minimize Transport Between Ecosystems
The most effective method of avoiding species introduction is to limit the geographic and ecologic range of each ROV.
ROVs dedicated to specific ecosystems can eliminate the possibility of invasive transport.
Users can minimize the amount of transport between ecosystems by planning their expeditions such that all dives in a specific site are completed contiguously, with the fewest possible transitions between geographically or biologically distinct regions.
When ROVs must be carried internationally, users should declare their ROVs at customs checkpoints and provide an opportunity for host nations to implement their own disinfectant procedures.
Much of this document based on the work by the following people who deserve credit and respect for their efforts to spread best practices and not invasive species.
Andrew Thaler -- read more at Thaler’s amazing marine science blog
Amy Frietag -- check out Amy’s research site
Erika Bergman -- follow Erika’s adventures (she drives submarines!) on twitter
Dominik Fretz -- follow his outstanding photography on instagram
William Saleu -- follow William’s adventures on twitter