Issues with entanglements are not restricted to these regions or species. Whale and dolphin entanglements also occur in the Pacific, prompting California zone closures and changes to crab fishery regulations. Entanglement issues have also forced the closure of the Black Sea Bass pot/trap fishery in the Southeast US. Although Congress legislated a pause in such regulations until December 31, 2028, more closures are expected to follow.
To allow commercial trap fishing to proceed, new regulations authorize the use of ropeless equipment, also called on-demand systems or pop- up gear. Ropeless gear uses acoustic technology to facilitate communication between surface vessels and submerged traps, eliminating the need for ropes and the associated risk of entanglement.
Addressing Conflict
Acoustic signaling for release has been around for decades. However, removing buoys from the surface presents new problems. Gear conflict arises when fishermen cannot distinguish between gear belonging to themselves and equipment deployed by others. They may retrieve incorrect gear, trawl over existing deployments, or deploy their gear over someone else’s by mistake. It’s no surprise that gear conflict has been one of the primary issues preventing industry-wide deployment of on-demand equipment.
Underwater acoustic technology has been recently developed to replace traditional buoy and line systems. Rather than using a rope to connect buoys and traps, the acoustic system allows fishermen to locate and identify their gear and that of others.
A Functional Buoy Replacement
A traditional surface buoy serves many functions in fishing operations. The most obvious is to allow a fisherman to locate and retrieve deployed traps. It also notifies other fishermen that gear is deployed on the seafloor. Typically, fishing trawls (a string of traps attached by groundline) use two buoys to delineate the length and orientation of the trawls so other fishermen don’t set traps over existing deployments. Buoys also alert mobile gear fishermen of the presence and location of submerged gear.
Buoys also help law enforcement monitor trap deployments to make sure fishermen are using the right gear in the right locations at the right times. Legal authorities can easily check that submerged components meet regulations, and buoys make it easy for regulatory enforcement to haul illegally deployed gear when necessary.
To allow for on-demand fishing where significant gear conflict exists, the following functions are required:
- Recovery (release): send command to seafloor system to surface; AKA the “on-demand” function
- Ranging: measure the distance (slant range) from a vessel to a seafloor system
- Positioning: measure the latitude/longitude of all gear on the seafloor
- Gear Ownership
- Gear Type: singles vs. trawls
- Gear Information: depth, temperature, battery life
Function 1 is the minimum acoustic function required for on-demand gear retrieval, and interference is not an issue. Functions 2–5 are required to prevent gear conflict in certain fisheries, and function 6 is nice to have but not required. Because these acoustic functions must be performed by multiple vessels operating in the same area, often simultaneously, the potential for acoustic interference is high and imposes a need for acoustic interoperability.
Underwater acoustics can be used to replace the buoy for all of these functions, but it was only recently that the acoustic technology required to do this became available. Ropeless Systems started with a clean slate and took several years to implement, test, and verify the system’s efficacy.
Ropeless RISER™ MTA installed in protective cage with gas cylinder and flotation bag. (Image credit: Ropeless Systems)
Complex Operations
The most difficult and unique challenge presented by on-demand fishing is the requirement that many non-cooperative vessels be able to track many sets of gear, both owned and non-owned. This requirement is referred to as multi-access.
Multi-access technology has been in use by the cellular phone industry for decades. To address the need for multiple devices to signal within the same geographic region, radio communications companies developed Code Division Multiple Access (CDMA). This technology allows devices from different phone manufacturers to communicate over different carrier networks. It’s what lets your Apple iPhone and your neighbor’s Samsung Android connect to the same Verizon network, for instance.
Although acoustic technology has previously been incorporated into marine research, military, commercial, and environmental applications, existing technology was insufficient to address the more complex multi- access challenge faced by commercial fisheries.
Ropeless RISER™ MTA surface system is installed on fishing vessels and consists of a hull- mounted transducer and transceiver. (Image credit: Ropeless Systems)
Ropeless Systems, Inc. addressed these issues by establishing the underwater acoustic equivalent of CDMA to prevent interference between acoustic signals. They advanced the technology to further allow multiple vessels to perform acoustic positioning and release of seafloor gear in the same area. This new design effectively addresses changing ropeless fishing requirements and the unprecedented challenges facing commercial fishermen.
How It Works
Ropeless Systems, Inc. has created the most advanced trap fishing system on the market, Ropeless RISER™. This system incorporates seafloor transponders called MTAs (Multicode Transponder Actuators) and our Single Ping Positioning ™ acoustics technology. The system provides users with a real-time, handsfree, chart plotter-integrated display of gear on the seafloor. The same system gives chart plotter display to mobile-gear fishing vessels that need to see all the gear (but not recover anything) and law enforcement agencies that need to see all the gear and to recover any of it.
Mobile gear vessels can also attach MTAs to trawl nets, doors, sleds, and dredges. Using the chart plotter, users can track the precise location of submerged equipment, which allows them to avoid interfering with other equipment and fixed-gear deployments.
Ropeless Systems’ Ropeless RISER is an acoustic-only approach and was developed with the unique needs of commercial fishermen in mind. Acoustic-only means that no cloud-based GPS marking is required. Everything works acoustically and locally when the fishermen are fishing in an area. It is a digital/virtual version of their existing operations.
Ropeless Systems conducted thorough testing and incorporated actionable feedback from industry insiders. Using the latest multi- access acoustic technology, Ropeless RISER provides significant operational improvements that benefit commercial fishing operations all the time, not just during mandated closures.
To learn more about these ropeless solutions, visit: www.ropeless.us
This feature appeared in Environment, Coastal & Offshore (ECO) Magazine’s 2024 Summer edition Fisheries & Aquaculture, to read more access the magazine here.
