The need to detect and assess jellyfish is driven by a variety of interests and concerns. Certainly most of us are aware that the sting from some species of jellyfish may cause painful wounds or even death, prompting the use of warning flag systems, barrier nets, and advanced sonar systems to protect swimmers at public beaches. Compounding this threat of physical harm, jellyfish populations in many of the world's oceans are know to dramatically and suddenly fluctuate, and often without cause or explanation. Despite the significant hazards posed by contact with jellyfish, the mechanisms controlling their movements and population dynamics are not well understood. Scientific echosounders are a proven, reliable instrument for the detection and measurement of jellyfish, and these specialized sonar systems are used by researchers worldwide for a wide range of studies. Their body structure of a jellyfish is dense enough to reflect pulses of sound (pings) emitted by sonar, and thus jellyfish are quite well-suited for the use of hydroacoustics. Over recent years, researchers around the globe have developed a wide range of interesting sonar methods and equipment for their study and this article documents just a few of these projects and case studies.
Due to shifts in ocean temperatures and currents, populations of so called “giant jellyfish” can rapidly increase or “bloom” and spread to new areas. Blooms of these massive creatures wreak havoc on commercial fishing operations by fouling nets and reducing fish catches. Predicting the movements and locations of giant jellyfish can help fishermen avoid the animals, and thereby increase fishing catch rates and efficiencies.
Dr. Kyounghoon Lee, of Chonnam National University in South Korea, has extensively studied the giant jellyfish, Nemopilema nomurai, using a split beam echosounder integrated with an acoustic camera and CTD sensor deployed from research vessels while conducting mobile surveys. Results from Dr. Lee’s work provide information about the sizing distribution and migration patterns of the animals in the Yellow Sea and East China Sea. Below you can see images of the giant jellyfish
Another Korean researcher, Dr. Kang Do-Hyung with the Korean Institute of Ocean Science and Technology (KIOST) has done extensive work using a multi-frequency BioSonics split beam echosounder studying the acoustic target strength (TS) of several jellyfish species, including the giant jellyfish Nemopilema nomurai Kishinouye. Some of Dr. Kang’s work involved using tethered jellyfish in net cages with the echosounder transducer affixed to the top of the cage. TS data derived from this research can be used for developing acoustic scattering models, and surveying giant jellyfish distributions and biomasses. Below, you can see a diagram of Dr. Kang's experiment with tethered jellyfish and a sonar echogram showing the jellyfish
Jellyfish increasingly cause significant problems for power plants, and other industrial facilities that intake large amounts of cooling water, when swarms of the organisms enter the water intakes and clog intake screens. Clogging events due to jellyfish blooms require laborious clean-up efforts and have caused total shutdowns of nuclear power plants in the United States, Scotland, Sweden, Japan, and Israel. Financial losses from such unplanned, sudden shutdowns can exceed 1 million USD per day. Below you can see power plant employees working to remove tons of jellyfish from water intake structures.
As a solution for power plant operators, BioSonics Automated Monitoring System (AMS) can be specifically configured for the detection of jellyfish, either for single, larger animals or dense aggregations of smaller individuals. Similar BioSonics systems are already in use at nuclear power plants in the US and Europe. The BioSonics AMS consists of a DT-X split beam echosounder coupled with a heavy duty PC running specialized software that processes hydroacoustic data in real time. Split beam transducers are fix-mounted in a horizontal or up-looking orientation and provide an acoustic curtain or “trip wire” to detect and classify objects in the water column at ranges exceeding 500m.
The project involves a DT-X SUB echosounder currently being deployed in a yearlong project to assess biomass (fish and plankton) in Papua New Guinea. The system is configured with 38 and 200 kHz transducers and operating in a fully autonomous mode. The DT-X-SUB is powered by (3) Ocean Sonics battery packs and will operate on a 15% duty cycle to extend battery life and allow for 3-month deployments. The hardware is mounted in a custom mooring frame deployed in 400 m of water. The DT-X SUB system will measure demersal and pelagic fish biomass and the diel migration of plankton over the course of this 12-month study.
BioSonics DT-X SUB is a programmable, autonomous scientific echosounder often used where tether cables to the surface are impractical. The DT-X SUB is ideal for deployments on moorings, ROV/AUVs, towed vehicles, and/or seafloor observatories. Echosounder duty cycle can be programmed to extend battery life for long-term studies. A single DT-X SUB echosounder can operate up to nine split beam transducers of various frequencies.
The DT-X SUB allows for long-term data collection in previously inaccessible, deep water environments, and studies of temporal distribution and marine organism behavioral patterns. Learn more about the DT-X SUB. Ocean Sonics Battery Packs are easy to handle and service. Each pack uses 72 standard D-cell units, with options for Alkaline or Lithium. The packs are available in two depth ratings; 200m and 3500m rated with titanium endcap and bottom. Lightweight glass fiber composite case eliminates cathodic issues found with metal cans. The endcap connector guard doubles as a lever making the release of the endcap a low-effort and safe procedure and the levers act as carrying handles for easy transport. Learn more about Ocean Sonics Battery Packs.
If you would like to learn more about BioSonics integrated solutions for submersible, autonomous echosounder deployments, drop us a line. We'd love to hear from you!
Aquapulse was the tool used for this amazing find!
The crew of a boat known as “Capitana” recently discovered over 350 gold coins! The Capitana is part of the 1715 Fleet-Queen’s Jewels, LLC historic shipwreck salvage operation. The famous 1715 fleet sank in the year 1715, with millions of dollars in lost treasures. The vast amount of coins just recovered were found on exactly the 300th Anniversary of the 1715 Fleet!
According to Brent Brisben, the co-founder of of the 1715 Fleet-Queen’s Jewels, LLC, there were 9 rare coins also found, known as “Royals”. Those coins are valued at $300,000 a piece!! Brisben also mentioned, in a recent press release, that the coins were meant for the King of Spain and these make up 30% of all the known Royals out there! Brisben said that all the artifacts were discovered in shallow waters, about 6 feet deep, off the coast of Vero Beach, Florida. The treasure hunter that made the amazing find was William Bartlett, near a location where Co-Captain, Jonah Martinez chose.
You can order your aquapulse here
Our scientific echosounders for fisheries and aquatic habitat assessment include everything you need to explore aquatic ecosystems using hydroacoustics. Our proven single and split beam sonar echosounder system are versatile, optimized for flexibility, reliability and ease of operation and include the data acquisition, real-time analysis, data visualization and post-processing software you need to get results.
DT-X Extreme Autonomous Portable Scientific Echosounder – This versatile echosounder is ideal for mobile surveys, or as a fully autonomous system for ASV/AUV surveys, surface buoys and other unmanned or fixed location monitoring applications for aquatic ecosystem research and management.
DT-X SUB Autonomous Submersible Echosounder – Our autonomous, fully submersible echosounder, for marine envoriments, optimized for ocean observatories and long-term AUV or ASV missions.
DT-X AMS Automated Monitoring Systems – Designed for fixed location, long-term or permanent deployments to monitor passage, migration and entrainment of fish and marine life or debris.
MX Aquatic Habitat Echosounder – A low cost, turn-key solution for rapid assessment and mapping of aquatic vegetation, substrate and bathymetry.