Baited Remote Underwater Video System (BRUVS)

BRUVS are a tool for monitoring aquatic animals like fish. BRUVS are made of a camera and bait container attached to a PVC or metal pipe frame. They are deployed in the water column or on the seafloor, usually for 60 – 90 minutes. Animals are attracted to the bait container and then recorded by the camera. The videos are later watched by a ranger, who records the species and number of individuals seen on camera.

There are two types of BRUVS, standard and stereo. Standard BRUVS use one camera and stereo BRUVS use two cameras. Stereo BRUVS need special frames and software, so they are more expensive to make. They are used to take body measurements.

Why are BRUVS useful?

Less stress for animals: BRUVS are non-invasive, meaning they don’t harm animals. They disturb animals less and won’t affect species behaviour as much as other methods that involve capture or humans in the water.

Watch again later: BRUVS create a video record that can be kept forever. This means different people can watch the same video, which reduces observer bias and allows for species IDs to be checked.

What can BRUVS monitor?

BRUVS can monitor animals that live underwater. Species, like culturally significant or threatened species, can be targeted to learn more about them.

You can also conduct general monitoring to:

• See which species live in the waterbody of interest.
• Investigate animal groups such as freshwater turtles, sharks and rays, or demersal (ground) fish.
• Check for pest or introduced species.

What can you learn?

BRUVS can help you to understand which species live in an area, how many individuals of each species, and what habitats they live in.

BRUVS can also tell you extra information about some animals such as:

• Individual ID: This can be used for a mark recapture study to estimate population size
• Male or female
• Behaviour
• Body Measurements: this can tell you how old individuals are and can suggest how the population is structured (are they all old, young, or a mixture), or how an area is used (if they are all young, the area could be a nursery). You will need a stereo BRUV, so consider if this is something that you need to know to decide whether it is worth spending the extra money and spending the extra time looking through double the footage.

You can study the effects of management by comparing a managed area to a non-managed area, or by conducting a before and after study.

What can’t you learn?

You can only learn about the animals where you deploy the BRUVS. For example, if you deploy a BRUVS on the sea floor, you won’t collect information on animals that live in the pelagic (open water) zone.

You won’t be able to learn about some species, such as:

• Species that hide, like cryptic or camouflaged species.
• Species that aren’t attracted to bait.
• Smaller species may not be detectable or identifiable using BRUVS.

Using BRUVS the Right-way

REMEMBER! Any time you do work that might disturb or interfere with native animals and vegetation, particularly threatened species, you need to check with the state authorities to see if you need any approvals, such as scientific licences or animal ethics committee permits.

A LOT of data:

BRUVS produce a large amount of data. Storing and managing data well is important to: 

• Make sure it is organised so that people can find data when they need to.
• Data doesn’t get lost or corrupted; and if this happens, recovery is possible, or back-ups are available.

You should also plan how you will analyse all the video footage your BRUVS record. This can be very time consuming.

Know the species you are monitoring:

Knowing which species you are planning to monitor will guide your site choices, the equipment needed and how you will deploy the BRUVS. Some species may be:

• Detectable at certain times of day. For example, Bell’s Turtle was not detected at midday in a study trialling BRUVS as a monitoring method for the species. The researchers suggest monitoring with BRUVS in the morning or afternoon. If the behaviour of the species you are monitoring is poorly understood you may need to run a pilot study by monitoring at many times each day to find the best time to monitor.
• Attracted to certain types of bait or not be attracted to baits at all.
• Live in certain habitats, so you will need to make sure you monitor where they are likely to be. If you are not sure you may need to run a pilot study by monitoring in all of the habitats to find where they live.

Choose the right sites:

Where you deploy BRUVS will depend on what your monitoring question is:

• Target one species – choose sites where the species is known to occur, or where there is habitat it prefers.
• All the species that live in a waterbody – choose a variety of sites that cover the different habitats.
• Compare areas under different management – choose the same number of sites in each management area, make sure sites in each area are similar e.g. same habitat, depth, water quality etc. 

Where you will be deploying BRUVs:

The species and type of water body that you are planning to monitor will guide what equipment is needed and how you will deploy the BRUVS. Below are some considerations for the main types of water bodies that you would use BRUVS in.

• Make sure you have a good field of view (what you can see through the camera).
• BRUVS deployed in strong currents will need to be weighted down.
• You will not get good footage in water with high turbidity (poor water visibility).

Deep water/ocean

• You will likely need a motorised boat
• If monitoring in the open ocean, you may choose to tow your BRUVS
• Deep water BRUVS need specialised set ups
• Strong currents or high wave action may affect the video quality

Creeks, streams or rivers

• You may be able to deploy BRUVS from kayaks/canoes or the shore.
• Frequently turbid.
• Recommended turbidity in channel pools is less than 10 – 15 NTU when BRUVS is less than 2 metres deep, and less than 5 NTU if BRUVS is more than 2 metres deep.

Wetlands and estuaries

• You may be able to deploy BRUVS from kayaks/canoes or the shore.
• Frequently turbid.
• Space BRUVS sites at least 100 metres apart.
• Deploy BRUVS at high tide in tidal channels, mud/sand flats and salt marshes.

Safety:

Ensure that you account for the additional risks that working on, in or near water poses to field staff.

Monitoring with BRUVS

You can learn more in the Environmental Monitoring Method: Monitoring with BRUVS (in development).