5 Ways ROVs Can Help Mitigate Risks Concerning Fish Health
Andrew Lawrence | March 16, 2020
With the total annual aquaculture production contributing to 45% of the world’s aquatic product consumption, the importance of aquaculture on the global food market cannot be overstated. As with any food resource, sustainability and animal welfare is a top priority. Keeping infrastructure and equipment in proper operational condition and ensuring compliance with health and welfare standards is of paramount importance to Deep Trekker.
The importance of fish health and welfare is increasingly being recognized by fish farms as vital to sustained profitability. Maintaining fish health at sea these days is a constant battle. Ocean acidification, rising sea temperatures, toxic algal blooms, endemic viral, bacterial and fungal diseases, pollution and of course the scourge of sea lice are all growing challenges. Keeping your fish healthy requires a serious amount of capital investment and extreme levels of husbandry.
What is an ROV?
An ROV, or remotely operated vehicle, is a highly maneuverable, submersible vehicle equipped with a camera to provide operators with a live view of underwater environments. Intelligent and easy to use, ROVs are durable and portable solutions for submerged inspections.
With an ROV, operators can get eyes underwater quickly and easily to inspect their farm. Offering a safe, convenient and economical alternative to divers, ROVs are changing how fisheries are maintaining their pens.
How can an ROV improve the health of your stock? Read on!
Morts are an unfortunate part of aquaculture. The quick and effective removal of these morts is imperative to maintain the health of the remaining fish.
Retrieving and analyzing morts is important as it gives operators insight as to why stock may have died - allowing operators to quickly pick up on signs of stock health concerns like ISA, for example.
With Deep Trekker’s Mort Retrieval System, users are able to easily spot and retrieve morts. From there morts can either be pushed into the mort retrieval system or brought to the surface for examination with the easy-to-use net apparatus.
Monitoring Behaviour and Feeding Processes
Having worked for EWOS for several years, our Aquaculture Specialist, Andrew Lawrence understands that the aquafeed you choose has a direct impact on the health and welfare of your fish. Further, feed regimes are strategically timed based on environmental factors like seasonality, water temperature, prevalence of particular diseases, algal blooms, and so on. Specialty feed types tend to be extremely expensive due to the many supplemental vitamins, minerals and amino acids. For these reasons, it’s imperative that farmers maximize the utility of these feeds. Many of our customers are using our ROVs and the DTPod submersible camera to minimize feed waste. A Deep Trekker ROV or DTPod is a vital tool for any effective feed management strategy.
Feeding to satiation is a very common practice, but it really only allows you to see when fish at the surface have fed adequately. Weaker or smaller fish below the surface may not be able to compete for feed at the surface, and by the time feed has reached them it may be minimal, or it could have floated out of the pen entirely. A DTPod can be suspended by a winch and then rotated to ensure you’re getting a full picture of how satiated all of your fish are. This may also cut down on the amount of grading necessary, saving vital time that can be spent on more productive tasks. These are the kinds of health and welfare risks that can be mitigated with a Deep Trekker.
In this age of increased microbial risk, it’s important that tools can be easily decontaminated. Deep Trekker ROVs can be decontaminated with a variety of solutions typical of what you would use in a boot dip for example. This allows users to move from farm-to-farm without dramatically raising the risk of bringing harmful microbes with them. This is especially handy if your ROV is shared between land-based facilities and sea sites.
Deep Trekker vehicles are powered by long-lasting on-board lithium-ion batteries. Because you don’t need generators to run them, Deep Trekker’s ROVs reduce the risk of spilling fuel around the farm and thereby contaminating pens or raising the risk of fires.
Deep Trekker ROVs are highly portable, in their cases or when carried on their own. The DTG3 can easily be handled by one person without significant risk of musculoskeletal injury. The Revolution can too, but it’s recommended to practice a bit more caution (i.e. lift with your knees) or get a colleague to help. This is very important because a healthy, happy farm team means husbandry doesn’t suffer.
Water and Sediment Samples
A Deep Trekker ROV can also be used to monitor environmental conditions, which have an immediate effect on health and welfare. Sampling is time-consuming and raises the cortisol level of fish. At certain times of the year when oxygen levels are lower, farms try to minimize handling to prevent loss. A DTG3 is a useful alternative to help assess fish health, while not meaningfully affecting cortisol levels. The new DTG3 has built-in temperature, depth and oxygen sensors available, so you can get an accurate environmental profile of each of your pens in mere minutes. We’ve also partnered with Aquatroll to integrate their multiparameter sonde onto either of the DTG3 or Revolution. The sonde can simultaneously carry up to four environmental sensors, like chlorophyll or phosphorus. It’s conceivable that one of our ROVs could be used to detect algal blooms before they reach your farm, or potentially in RAS to detect dangerously high levels of nitrogen.
A safer and more easily-deployable alternative to commercial and staff divers, Deep Trekker ROVs provide operators with a reliable way to perform daily net inspections.
With an ROV, operators can easily make net inspections a part of their daily routine to quickly monitor the daily wear and tear that can cause fish escapes, but also to identify holes when pest incursions are suspected.
Often fish farms are located in rural and remote areas that are hard to reach. These days, many commercial dive teams are unwilling or unable to get to remote sites in a reasonable amount of time. If you suspect you have a hole in your net, the easiest way to find out is to deploy a DTG3, which can be done in less than 30 seconds. If you spot a hole and you can’t get a diver in to patch it right away, Deep Trekker’s new Net Repair tool can be mounted right on the front of the DTG3 and can cover or pull holes shut, which should buy you some time until you can get a diver down to do the complete repair.
ROVs are far less intrusive than divers, which can go a long way to reducing fish stress which would would otherwise render their immune system compromised.
We spoke to Sverre Føyen , Site Manager of Erko Seafood’s Hardanger locations, to see how he and his team use their Deep Trekker ROV. You can also learn more about the use of ROVs in aquaculture in The Cost Benefits of Using an ROV in Aquaculture.
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