Locating "Ropeless" Fishing Gear

The Project 

Context

Traditional fishing gear (crab/lobster trap) leaves a floating rope and buoy behind as fishermen sink the equipment into the sea. All these floating ropes connecting the cages at the bottom of the ocean to the water's surface have entangled other marine creatures, such as whales swimming by. As a result, there is a compelling need for "ropeless" fishing gear, also known as on-demand fishing gear, which mitigates the issue of endangering irrelevant marine creatures by minimizing the use of ropes.

Current Solution and Problems

Our sponsor, Sub Sea Sonics, has developed a mechanism that releases a rope and two buoys from the trap only after the preset timer ends or the trap receives a dedicated acoustic signal. Since there is no buoy to look for, to record where they placed the trap, Sub Sea Sonic made an app that shows a nautical chart (on-sea map), where the fisherman can overlay an indicator by tapping a button that records the device’s GPS location, that data is then recorded and uploaded to a database along with the date and time of record when there is internet access. However,  this solution led to two problems: 

1. The officials enforcing fishing area restrictions have no reason to believe the fishermen’s self-reported trap deployment locations.

2. Since errors are expected from both on-sea navigation and sea current, fishermen returning a few days later after deployment are not likely to stop exactly above where the fishing gear is, so they have to look for the buoys after triggering the release. This is especially difficult on days with low visibility due to weather conditions.

Our Objectives

In response to the problems, we were tasked to design:

1. A tag/component/software that can reliably record the deployment location of the fishing gear(s), ideally a tag attached to the cage(s).

2. An add-on to either the buoys or the rope that makes them easily visible/detectable by the fishermen after coming up to the surface.

Design Requirements

• Functional Lifetime Per Unit: ≥ 6 months 

• Cost Limit: few hundreds is fine for this , but needs to be able to be brought down to $100

• Size Limit: ≤ 7 in × 6 in × 13 in (17.78 cm × 15.24 cm × 33.02 cm), negotiable

• Durability:  Able to withstand the pressure at 300 to 1000 ft (91.44 to 308.4 m) below the sea surface, as well as the cyclic load of deployment and retrievement

• Functioning mechanism: Two-factor location authentication, transmission of latitude and longitude at surface

THE SOLUTION

A device in a PVC pressure vessel that sends out radio signal of its resurface position and records its retrieval position for comparison with the reported deployment location.