Comparing Fish Surveying Methods in MPAs of Western AustraliaLatest update August 13, 2019 Started on January 14, 2019
My expedition is taking me to Marine Protected Areas in Western Australia. Where I'm comparing two fish surveying methods; Diver Operated Stereo-video and micro Remote Operated Vehicle, analyzing fish assemblage and behavioural impacts.
The New ROV arrived!!!
A few weeks back I received the Trident! This ROV is absolutely great and I can't wait to take it out in the field. I must thank the S.E.E. Initiative and OpenROV (Sofar Ocean) for helping me get this new ROV, as well as a big thank you to everyone who has followed my expedition and made this possible. So, thank you!
Over the last month I've been conducting my video analysis from the Exmouth field trip data. It's becoming clear that fish tend to be wary of SCUBA divers conducting DOV surveys, as well as expressing high frequencies of flight responses when the fish spot a diver. It'll be interesting if these flight responses are still present in the ROV footage. In fact, further research can now possibly test the difference between ROV brands and designs with help from the new Trident ROV.
Thanks again for the support guys!
I've been analyzing some BRUVs (baited remote underwater videos) footage for another student this past week. I came across some footage of a Stingray (Blackspotted Whipray (Maculabatis astra)) that seems quite intrigued by the bait bag. I just through I'd share this interesting footage!
Just an update my the video analysis!
Its becoming clear that there are minimal behavioral imparts towards fish when surveying with an ROV. I've attached some screen shots of a school of Convict Surgeon-fish (Acanthurus triostegus), mixed with rabbit-fish (chlorurus sordidus) and parrot-fish (Siganus fuscescens) from Coral Bay, Western Australia. These school illustrated minimal changes in behaviour towards the ROV. This is a promising sign for use of ROVs future, highlight the associated strengths and efficiencies when surveying reef fish.
Just thought I'd share this piece of footage we recorded during the last Exmouth trip using the ROV survey method. The Lemon shark (Negaprion brevirostris) observed doesn't seem to be impact the Lemon Sharks behaviour. In fact, this was recorded at North West Reef (outside Lighthouse Bay marine park) where fishing pressure from both boat fishing and spearfishing is present.
The ROV gave us trouble this trip, which required a lot of time and effort to be put into the underwater vehicle. After having various parts and boxes shipped up to Exmouth and numerous late nights, the ROV was functional. We were able to salvage parts from two ROVs to create one ROV that would be able to complete the work. The ROV's function of depth hold and stability control were not working and we had a small unknown leak, but the ROV could drive transects, which meant we could collect data. However, due to thrusters and wiring being changed over, the ROV required calibration of each thrusters when we drop into the water. Although, saying that; we were able to overcome these issues and control the ROV enough to complete transects. (I've attached a photo of our computer system and ROV control set up on the research vessel).
We manage to collect the data required for my DOV and ROV research. A window of great weather allowed for us to take full advantage of Exmouth's marine environment, completing both Lighthouse Bay and Tantabiddi sites. Each of these sites consisted of 3 reserve (protected) reefs and 3 non-protected reefs (Lighthouse Bays outside sites at North West Reef) which were surveyed by both DOV and ROV methods. These reserve reefs are completely no fishing zones, thus these areas experience no fishing pressures. While the outside reef sites are exposed to fishing; both spearfishing and both fish. However the Tantabiddi outside sites have a modified spearfishing regulation, limiting the species that can be targeted by spear fisherman. This will be interesting to see if the targeted species are seen in lower abundances with higher wariness at both sites. On the other hand, I'll be looking to see if the species protected (from spearfishing) at Tantabiddi are seen more frequently at Tantabiddi in comparison to North-West reef where the threat of spearfishing is prominent. It'll be a key point to identify if there are any differences in assemblages and behaviour seen between the ROV and DOV. Ideally, due to the ROV survey method potentially removing the diver bias, the ROV will be able to highlight a more realistic representation of the marine environment at each site.
Through looking at the videos obtained during this trip, it's evident that fish tend to be less wary inside protected areas no matter the survey method. However, once outside these protected areas and exposed to fishing pressures, fish tend to be wary towards DOV surveys and have shown (only through visual tends) to minimal behaviour changes towards ROVs (in comparisons to DOVs). Video analysis will be the next step back in Perth at Curtin University, which will hopefully highlight more tends and explanations.
We have been using the ROV the past two days.
Yesterday we got the ROV out to Lighthouse Bay, the weather was casualty perfect. However, once we placed the ROV in the water, the controls were all wrong and we had to manually calibrate each thruster (propeller) and the direction in which they spun. After 3 hours, we managed to get the ROV to be drive straight enough to complete the first lighthouse site.
Today started off perfect, we manage to complete the 2 remaining sites at Lighthouse Bay! Together with the once again perfect weather, the ROV surveying was going super smooth. The next site was at North West Reef which was evident to have quite a strong current. The ROV was performing great until 15 mins into the dive, we lost all communication and power to the ROV! Once we got the ROV back on deck, we realized we had burnt out some wiring. Reasoning? We believe it was from trying to drive against current for too long, and it simply over heated and burnt out the wires. We luckily have the exact part we need with our spare parts. However, the one plug doesn't match the rest, so this new part is useless at the moment.
So the ROV work has come to a stop once again. Tomorrow we'll do some BRUV drops around the Artificial Reef, while we consider our options to fix the ROV.
Tantabiddi was a success! We completed all the sites apart from 1 dive, which we will complete later in the week.
We have some good news about the ROV, we got the camera tilt working and we managed to get the thruster unblocked! Only issue is that the depth sensor isn't working, but that isn't essential for the surveying tomorrow. Tomorrow we will use the ROV at Lighthouse Bay.
Hopefully everything goes to plan!!
We made it to Exmouth last night, and we were able to do some diving today.
We dived the Lighthouse Bay MPA today, as well as sites at North West Reef for the outside MPA replicate. Lighthouse bay produce a large diversity and abundance of fish, it was truly amazing. This is a key example a marine park that is efficiently working! We are diving Tantabiddi lagoon tomorrow, inside and outside that MPA zone.
We fired the ROV up today, and we have issue once again..... One of the motors/thrusters seems to be blocked and another thruster is constantly spinning. In addition, the camera tilt isn't working, so these are some major issue that need to be addressed!!
Fingers diving is good tomorrow and we can fix the ROV before we need it.
Today was successful! We had two dive boats out of Port Gregory and Drummond Cove, and we were able to complete 3 sites. Weather was good, we had a little bit of rain whilst at Port Gregory and visibility was surprising good.
We are staying in Geraldton tonight, and we'll leave for Exmouth early tomorrow morning.
We are heading back to Exmouth! Hopefully trip will seeing some good weather (no cyclones). The trip will run for 2 weeks, completing DOV and ROV surveys inside and outside MPAs, as well as some additional ROV work on the artificial reef.
The plan is to head up to Geraldton (5 hours away) for a day to complete from DOV surveys from my supervisor. Then continue another 10 hours north up to Exmouth.
Just an update, the research questions have from my research have slightly been altered to ensure the workload maintains achievable. The broad scale study has been removed, and the research will now focus on the comparison of DOV and ROV surveys in Marine Protected Areas along the Ningaloo Reef. The use of the MPA will help act as a control, where we are expecting to see significant difference outside the MPA. This will highlight any limitations and bias involved with each survey method.
Video analysis is slowly taking place with an evident visual trend. In comparison to the DOV footage, the ROV footage that I'm analyzing now highlights fish as being less wary. It's clear that the fish behaviour is hardly influence through using the ROV technique. In fact, this trend is being seen in unprotected and fish areas, where research has shown that fish are more wary. Therefore, this is a positive sign for the research and future of ROV surveying.
Just an update;
I've been back in Perth at Curtin a few weeks now. since the Exmouth trip. Over the past few weeks video analysis has been the task. I've been analyzing footage from the Perth and Coral Bay sites. So far, it's visually evident that fish are more wary of DOVs than ROV survey, which is a plus as this is what we are expecting to see. Once this data is exported, we'll be able to analysis the data using Primer7, which will give statically reasoning and explanation. The plan is to use PERMANOVA's and associated statistical tests to test the data against the hypotheses.
The software; Event-measure, is the software being used (image below). This software allows for measurements of fish and distance from the cameras, highlighting the ability to calculate minimum approach distance. The goal is to measure the fish lengths and minimum approach distance (MAD), to create a linear regression looking at the length of fish and MAD. We have hypothesized that the MAD will increase as the fish length increases, linking with larger and therefore targeted species being more wary, thus wont approach the diver. However, we hope to see this tend across DOV surveys, but not in ROV surveys. Not seeing this trend while using the ROV, will highlight the impact ROV's don't have on fish behaviour, thus becoming a representative surveying method for fish species, with minimal bias.
Another Exmouth trip is bring planned for the mid to end of May. This trip back to Exmouth will enable my research to continue, exploring the marine sanctuary and fishing areas with ROV and DOV surveys.
The Exmouth trip is now finished, and we are home safe. The 14 hours trip was completed last night, with team returning the Curtin University around 6pm. The trip was a great learning curve, through gaining experience in water and sediment sampling, along with addition ROV and coral work in the Exmouth Gulf.
Unfortunately, this trip had certain components that were against us from the start. The bad weather visibility from the past cyclone Veronica caused visibility problems for the ROV and DOV surveys which led to further ROV technical issues. In addition, the formation of another tropical cyclone north of Exmouth resulted in large swells and winds down the coast and especially Exmouth, causing us to make the ultimate decision to cut the field trip short. On the other hand, we had technical issue with the ROV which limited the amount of data we were able to collect. From motors jamming and new motors spinning the wrong way, to condensation from the humidity and unknown leaks; the ROV wasn't fully function which contained the amount we could use it. Thus, our work isn't complete and we will be back to Exmouth, and we will finish our work with the potential aid new ROV. See you soon Exmouth. Logan
Looks like the field work may be cut short with a tropical cyclone forming in the north (Image below, as shown on Windy.com). It could potentially hit Exmouth in week, having various impacts. The Gulf's visibility will continue to drop within associated rough weathers. Plus, the cyclone will bring down large swells and winds to Exmouth making it unsafe to boat in the Gulf and around lighthouse bay doing ROV and DOV surveys. Thus, this will highly impact the amount of my research that is completed on this Exmouth trip. However, there's various different models showing different tracks which the cyclone takes, one hitting Exmouth, one hitting Karratha and one model shows the cyclone swing off the coast and missing all land. Although, whether or not the cyclone hits lands, the associated weather and ocean condition are almost certain. We'll have to keep an eye on this.
Today we did sediment sampling in the Gulf, which was quite productive and successful. The morning wasn't the best conditions we've seen throughout the week, with winds causing choppy ocean conditions. However, we braved the weather and got out for a few dives. The dives collected sediment samples from 2 sandy sites, and 1 artificial reef site. We didn't expect good visibility due to the videos we recorded yesterday with ROV in the Gulf. Although, the dives weren't involving filming, almost collecting sediment, thus visibility was too much of a concern. I did the second sandy site and the artificial reef site dives, which both had surprisingly good visibility of about 5 meter, which was a lot better than the 1 meter we expected.
The dive on the artificial reef highlighted the successful rates of recruitment of species and health on the reef. There was a large diversity of species and large number of individual species. For example, as we descended, we were circled by a school of Golden Trevally (Gnathanodon speciosus), as well as seeing large numbers of Spangled Emperor (Lethrinus nebulosus) and Spanish Flag (Lutjanus carponatus). We observed 3 Estuary Cod (Epinephelus malabaricus), that were all over a meter in length. In addition, it was great to see Coral trout (Plectropomus leopardus) and schools of juvenile Red Emperor (Lutjanus sebae) present around the reef. It was truly amazing to see the thriving health and abundance of species, especially targeted species, on the artificial reef. We saw species such as Lutjanus sebae, which have rarely been seen in the Gulf, thus the reef structures are doing a fantastic recruitment job. Thus, the visual success of the artificial reef highlights the potential for the use these reefs with future implications.
Once back on land, we had most of the day remaining. The weather in the Gulf had dramatically decreased down to minimal wind and swell, a typical Exmouth 'glass off'. My associates decided to take advantage of the great weather and continue to do the artificial reef research. BRUVs (baited remote underwater videos) were dropped on the sandy sites and the artificial reef. This is a project run by Recfishwest which will inform my associated honours research. The videos that were recorded on the BRUVs at the artificial reef, reinforce the diversity and thriving life at these reef structures we saw earlier in the day. I'll try to obtain some of the footage and post on the my expedition.
More ROV problems today. We planned to begin the day with ROV surveys, with the goal of completing all the artificial reef sites. However, as soon as the ROV hit the water and we tried driving towards the reef, we realized this wasn't possible. The ROV was just spinning and wasn't driving in the intended direction. When we pulled the ROV from the water, we came across two initial issue. One - the moisture issue from either humidity or a leak is back. Two - the recently changed propeller was rotating the wrong way.
Thus, we headed back to shore to combat these issues, so we could get back out on the water in the afternoon to complete some surveys. We identified 2 key ways which we could solve the propeller rotation problems, one was through software and one was through manually changing the propeller. Once we removed the propeller's protective casing and reached the actual (changeable) propeller blade, it was clear that the current blade was designed to spin counter clockwise. Where as, the original blade was designed to spin clockwise, therefore it was as easy as removing 2 small bolts from each propeller to directly swap over the blades. Now we had eliminated the propeller issue, we had to deal with the moisture problem. Once again, we checked all the o-rings, as well as drying out the wiring which was some what moist. We pressure tested the seals, which indicated there were no leaks, thus we added some silica gel packs to the main body tube to absorb any moist caused by the humidity and condensation.
With time still remaining, we were able to get back out onto the water and out the the artificial reefs. We had eliminated the driving and propeller issues, however the leak/moisture was back. Together with the drastic drop in visibility, the ROV work was becoming increasingly difficult to complete. We were using a damp towel to cover the ROV when on the boat, to minimize exposure to the sun and heat, with the goal to decrease the moisture in the ROV. However, this seemed to have minimal impact, as the bottom of the ROV tube keep filling with increased amounts of water. It was at this point, considering the risk of flooding the ROV with the leak and the ever increasing bad visibility, we decided to pull the ROV from the water and call it a day. Tomorrow we plan on diving for sediment samples, so we have no ROV work that can malfunction, we should have a productive day.
Today we continued to get the water samples from the artificial reef, and continue with the ROV surveys in the Gulf. However, we hit a major problem with one of the driving propeller motors on the ROV seizing up. We suspect it was due to the high amounts of sediment in the water as well as the bad visibility causing the ROV and driver to become disorientated, crashing into the sandy sediment seafloor. Ultimately, causing the suspended sediment to jam the motor from working.
We had to pull the ROV apart, dismantling the propeller from the main structure and remove the wiring which enabled us to thread the wires out. We managed to salvage a spare motor from our other ROV (which hasn't been holding pressure) and successfully re-wired and mounted the spare motor on the ROV. We connected the ROV to the tether and ensured the motor worked before we try it in the ocean tomorrow. Hopefully we have successfully eliminated this issue, and will be able to take control of the surveying while the wind and well remain low. Logan
Today we got the boat in the water for the first time this trips, and were able to complete a large proportion of the water sampling on the artificial reefs. In addition, we got the ROV in the water and sampled 2 sand sites (controls) and 3 artificial reef structures (towers, Apollo clusters and pyramids). However, the implications and effects of Cyclone Veronica are still present in the Gulf of Exmouth. Visibility was quite low, around 5 meters, which is still possible to use and conduct the surveys, just not the ideal conditions. The ROV preformed well, however, due to the high humidity and heat in Exmouth, stream and condensation is starting to form within the ROV's main wiring tube. We will have to keep a close eye on this! Tonight we plan to ensure there's no leaks (check all o-rings and vacuum test the seals) as well as purchasing some silica gel packs to absorb any unwanted condensation that may impact the wiring. Although, the water present in the ROV is minimal, and is nothing to worry about.
We have a stretch of 4 days of low wind and swell, so with a bit of luck, the visibility will clear up and we will continue to push through the field work. Logan
We made it to Exmouth! However, it was a few days later than expected due to Cyclone Veronica coming down the coast of WA and hitting Karratha (north of Exmouth). This cyclone impacted the quality of the water, in terms of conditions and visibility which isn't ideal nor safe for boating and ROV work. Although, on the 28/03 we received confirmation that these conditions had cleared, so we packed our bags and began the trip the next day. After the 14 hours and 1,265 km, the trip was complete and we are in Exmouth. The plan is to start the ROV surveys and water sampling on the Artificial Reef tomorrow morning.
We completed a day-trip down to Shoalwater Bay, WA, south of Perth. We managed to sample 3 sites at Shoalwater using DOV surveys. All sites were shallow reef, which all had surprisingly good visibility in comparison to previous dives at this location. We wouldn't have asked for better conditions out on the water, so we took full advantage and completed all 3 sites. Thus, now the DOV surveys are complete, we need to survey these same sites with the ROV to obtain the direct comparison.
The first major field trip for the expedition is planned for Exmouth, Western Australia. This will help complete the northern most locations of the study, with the aim of completing ROV and DOV surveys at 3 sites, which will ultimately collect data for the region of Ningaloo. The trip will take 14 hours, to drive our research boat and vehicle from Perth to Exmouth, which is over 1,200 km distance. Once in Exmouth, the team will stay for 3 weeks to complete the work, however due to the northern location in WA and time in cyclone season, cyclones are a risk which can terminate the field trip at short notice. While in Exmouth, addition work will be done with my associates, looking at the Artificial Reef in the Gulf of Exmouth. One of my associates will be collecting eDNA water and sediment samples to highlight the efficiency of eDNA sampling (working with TREND at Curtin), where species observed in ROV footage will be linked with the eDNA outputs. In addition, another associate will be using ROVs with stereo videos to survey the Artificial Reef structures and various control sand sites to expose the health and efficiencies of Artificial Reefs (Collaboration between Curtin and Recfishwest).
Finger-crossed we have a smooth field trip! Logan
Disaster strike today! We got up early and drove to Leeman, 16 km north of Green Head. The morning went smoothly, we conducted DOV surveys at 4 sites at Leeman. We were completed by midday, and headed back to the house to change tanks and have lunch.
We ventured down the road to the Green Head boat ramp to continue our surveying. However, this is where the major issues started. The boat ramp had just been cleanup by a digger, but this create a large sand bar a few meters back from the ramp. Thus, the water went from deep to dramatically shallow. When the boat was launch, fortunately, the outboard was driven straight into the sand bar. At close look, we released the steering had been impacted. In fact, it got worse with the outboard bracket (mounting to transom) becoming snapped right in half. This was the end of our trip as the boat was out of order, thus we couldn't reach our sites to complete the DOV surveys. We are currently on our way home, back to Perth, thus we'll have to head back to Green Head and Jurien Bay to complete DOV surveys, as well as an additional trip for ROV surveys. Logan
We made it to Green Head! Tomorrows plan is to dive 4 sites at Leeman in the morning and then head back to Green Head to dive 4 more sites. Jurien Bay sites will then be completed on Wednesday (20th).
Big day tomorrow, but the weather is looking promising, so we should be about to push through and complete the work. Logan
The potential use of a new OpenROV trident, would extremely benefit my research. My research is aiming to expose the advantages of ROV's for fish surveying. This will not only suggest OpenROV's as a superior surveying method, but will inform the scientific community about the strengths and advantages of overall ROV use. However, at a minimum, the research will aim to highlight ROV survey methods as similar to DOV (Diver operated videos) methods, thus the data and video footage will be comparable. There is currently minimal information and scientific paper which direct compare ROV techniques to Diver techniques in regards to fish surveying. This is where my research and the use of the trident ROV will help fill in the gap of knowledge and educate the scientific and general community about ROVs. These fish surveys play a vital role in informing the management and regulation of the marine environment, as well as generally informing the public about the changes seen or health of the environment and the animals with it. Thus, its essential we use the surveying method which best represents the marine environment, so the correct information is produced and the appropriate action can be put in place.
The research will compare the the limitation and strengths of both ROV and DOV surveys, with the goal of highlighting ROV as superior. In fact, this will be aim to be a general over-view about ROVs, however with the use of the OpenROV trident, this will specifically indicate the advantages off this ROV, and further promotes the ROV brand for fish surveying. If ROV's don't initiate fish responses and behavioral impacts such as flight response and minimal approach distance, in comparison to diver methods, this will further push and highlight the use of ROV for both recreational and scientific purposes. Recreational users want to see the most amount of fish for an aesthetic image or photograph, and scientific surveys just aim for the best image that represents the marine environment and associated fish populations. I feel the OpenROV trident is the perfect candidate to prove my hypothesis and promote the use of ROVs.
The aid of an OpenROV trident will expanded my research in both spatial and temporal sense. This is allow for my research to push beyond the constraints of the university, surveying more sites at a more frequent rate. Recent surveys have demonstrated issues with our current ROV, from propeller motor jamming and blowing, to constant leakages from unknown sources. This is a major limitation of my research at the moment, containing the amount of data that is being collected.
We are planning a trip to Green Head, Western Australia (red pin drop), with the goal of completing the Jurien Bay region of sites. This region includes 3 sites at Jurien Bay, Green Head and Leeman. The trip will be primarily to conduct DOV surveys, with ROV surveys being complete on another trip. Green Head is 263 km from Curtin University (Perth), which will take just over 3 hours to drive up there with the research boat. Weather is looking good, wind isn't the best, but it is definitely possible to complete DOV surveying.
Western Australia’s reef fish assemblages are experiencing rapid change as a result of climate change and increasing the surface temperatures (Bennett, Wernberg, Harvey, Santana-Garcon, & Saunders, 2015; Cheung et al., 2012; Pearce et al., 2011; Wernberg et al., 2016). Given the emphasis on commercial and recreational fishing in Western Australia and the potential vulnerability to cumulative impacts of many endemic temperate reef fishes (Fox & Beckley, 2005; Hyndes et al., 2016), it is becoming increasingly important to undertake surveys of reef fishes across a broad latitudinal gradient on an increasing frequency to be able to understand and predict how endemic fishes may respond and potentially adapt to climate change (Cheung et al., 2012). This information is also required to inform managers and the general community about what changes are occurring. This will enable the implementation of suitable management with community support.
Counts of the abundance or density of reef fish are routinely used as a metric for spatial and temporal comparisons and descriptions of impacts to fish assemblages (English, Wilkinson, & Baker, 1997; Kingsford & Battershill, 2000). In contemporary fisheries management and conservation, biomass is considered the most sensitive metric to protection from fishing (S. Jennings & Greenstreet, 1999; Simon Jennings, Marshall, & Polunin, 1996). A recent study on periodically harvested fisheries closures, suggests that distance between a fish and the observer may be more sensitive to changes in fishing pressure than both abundance and biomass estimates (Jordan S. Goetze et al., 2017). Diver Operated Stereo-Video (stereo-DOV) is increasingly being used as a monitoring tool to assess the abundance and biomass of fishes (Shedrawi et al., 2014). Stereo-DOVs are one of the most accurate methods for detecting the impacts of fishing in small-scale fisheries ((J. S. Goetze et al., 2015); in particular for herbivorous species) and more recently have shown potential for collecting distance data which can be used to assess fish wariness (Jordan S. Goetze et al., 2017; Gray et al., 2016; Lindfield, Harvey, McIlwain, & Halford, 2014). DOVs are conducted by scuba divers, who swim transects which are film by the DOV system for analysis in the lab. The measurement of distance between a diver/observer and fish used in stereo-DOV, called Minimum Approach Distance (MAD), is obtained by making a length measurement when the fish is at the closest point to the stereo-DOV system and uses the software EventMeasure Stereo (www.seagis.com.au)) to automatically calculate this distance. In addition to DOVs, there are Micro Remote Operated Vehicles equipped with a stereo-video (ROV). Ultimately, these ROVs are underwater drones which are controlled by the remote on the boat. Like DOVs, the ROV drives transects and films the transects using stereo-video.
The research will collect data on reef fish assemblages by sampling transects at the same sites across a tropical and temperate gradient. The research will run down the coast of Western Australia to obtain a broad latitudinal gradient. Therefore, the expedition sites will range from Exmouth to Jurien Bay, Perth Metropolitan waters, the Capes region and Albany) using a stereo-DOV and Micro ROV equipped with an underwater stereo-video system. We will compare several metrics including the assemblage composition, the length frequency, biomass and the minimum approach distance of the assemblage and indicator species. We will also sample inside and outside of three sanctuary zones where there is contrasting fish assemblages.
The objective of this research is to compare reef fish data collected with a Diver Operated Underwater Stereo-Video system and a Micro ROV equipped with a stereo-video and assess the biases, strengths and limitations associated with each technique.
A pilot study was run on the research question of comparing reef fish data collected with a Diver Operated Underwater Stereo-Video system and a Micro ROV equipped with a stereo-video. The study was conducted in Coral Bay, in 2018. The study specifically looked at the comparison of ROVs and DOVs inside and outside a Marine Protected Area, that is closed to fishing. Thus, adding a specific sub-question of influence of Protected Areas. The aim was to highlight any potential impacts of fish wariness on the different sampling methods. A design of 6 sites, 3 outside and 3 inside the protected area, while 25m transects (12 replicates) were sampled. The study interestingly found that there was no significant different between ROV and DOV sites inside the protected area with regards to fish assemblage and individuals fish counts. However, there was a significant different of fish assemblage and individual fish outside the protected area. The study indicated that the ROV surveyed significantly more fish than the DOV outside the protected area. This highlighted the potential difference in fish wariness inside and outside protected areas with respect to different sampling methods. Therefore, suggesting potential bias involved with divers and associated bubbles when sampling fish assemblages.
This expedition has the ability to suggest that ROV methods are similar to even better than DOV methods. This research will help indicate to the scientific community and industry the ability and constraints of ROVs and DOVs, ideally identifying the most suitable and sustainable method. The research can indicate that ROVs can produce the same to better quality sampling than DOV. ROVs also have various other advantages and benefits that help reduce the costs and risks involved with underwater surveys. ROVs are controlled from the boat, thus eliminate the need to scuba dive and buddy divers for sampling. This reduces the number of fieldwork team required, thus reducing costs. In addition, scuba divers require surface intervals between dives, which puts constraints on fieldwork time. Whereas ROV don't have this constrain and can continue to sample until the batteries have run out, which are easily changeable. ROVs can also dive depth that scuba diver DOV samples can’t reach, while scuba is contained by oxygen, ROV doesn't experience this limitation. In addition, removing divers from the water also eliminated the risk involves with getting injured and illness associated from diving. In fact, there's associated risk with dangerous marine fauna. This is becoming a large issue in Western Australia, with the fear of Great White Sharks (Carcharodon carcharias) limiting the amount of researcher wanting to dive for research. Thus, there's a huge potential for ROV sampling in the marine industry.
My expedition to complete research on compare reef fish data collected with a Diver Operated Underwater Stereo-Video system and a Micro ROV equipped with a stereo-video and assess the biases will highlight vital differences between 2 commonly used sampling methods. The hypothesis are;
Hypothesis 1. We hypothesise that across a broad environmental gradient there will be no technique difference in the metrics of the data generated by with a Diver Operated Underwater Stereo-Video system and a Micro ROV equipped with a stereo-video.
Hypothesis 2. We hypothesise that inside and outside of two tropical marine sanctuaries there will be differences in the metrics of the data generated by with a Diver Operated Underwater Stereo-Video system and a Micro ROV equipped with a stereo-video.
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Cheung, W. W. L., Meeuwig, J. J., Feng, M., Harvey, E., Lam, V. W. Y., Langlois, T., … Pauly, D. (2012). Climate-change induced tropicalisation of marine communities in Western Australia. Marine and Freshwater Research, 63(5), 415–427. https://doi.org/10.1071/MF11205
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Goetze, J. S., Januchowski-Hartley, F. A., Claudet, J., Langlois, T. J., Wilson, S. K., & Jupiter, S. D. (2017). Fish wariness is a more sensitive indicator to changes in fishing pressure than abundance, length or biomass. Ecological Applications: A Publication of the Ecological Society of America, 27(4), 1178–1189. https://doi.org/10.1002/eap.1511
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