Worldwide, Drifting Fish Aggregation Devices (DFADs) are used in fishing operations to attract fish for harvesting. DFADs are regularly left at sea due the cost of their recovery. These DFADs damage sensitive ecological habitats and contribute to ghost fishing and plastic pollution. Low-income coastal communities bear the burden of this practice.

Many DFADS are accompanied by a satellite connected echsounder buoy for detecting fish and locating the DFADs at sea. Here, we will convert used DFADs buoys into 3 different solar powered buoy installations:

* A reef camera

* A hydrophone

* A water quality monitor

Our goal is to motivate their recovery, decrease their impact, and provide the best open-source platform for marine reasearch.

After the DFAD is launched from the fishing vessel, it will drift freely in the ocean until it either detects fish or runs ashore. In the Indian Ocean, a single purse-seining vessel is allowed to deploy 300 such DFADs a year depending on the region. Photo provided by Alex Hofford under the creative commons license.

The subsurface structure of the DFAD attracts marine life while its accompanying echo sounder buoy can remotely detect the prescence of tuna shoals. Photos provided by Alex Hofford under the creative commons license.

This a top view of the sub-surface structure of a DFAD. Many DFADs have structure that extends 50 meters below the FAD. Photo provided by Alex Hofford under the creative commons license.

While most are never recovered, here we see a crew of conservationists unentangling a DFAD that has grounded on a coral structure. Photo by Blue Safari Seychelles and is not for redistribution without their express consent.

Recovering a grounded DFAD with echo sounder buoy in view. Photo by Blue Safari Seychelles and is not for redistribution without their express consent.

Old, broken, or unused echo sounder buoys near a fishing port.

DFAD Shakedown:

While the commercial fishing industry has access to these mass produced buoys, the conservation and research sector does not have access to this level of remote technology at this price point. While DFADs are certainly an environmental hazard, they also represent untapped resource for coastal communities.

Furthermore, carbon credits and debt-for-nature swaps are creating a need for sustainable, cost-effective monitoring globally, as more and more nations try to quantify the benefit their local environment contributes to global ecological health.

These three projects can help meet those needs while incentivizing larger scale reclamation and recycling programs.

Check out the build instructions below for a step-by-step guide.

As we delve into the challenges of remote marine monitoring, it becomes evident that equipment cost, environmental hazards, post-processing, and delayed feedback are significant barriers to researchers and conservation workers.

Equipment Cost

The high equipment cost in marine monitoring arises from the harsh oceanic environment, limited demand, intensive service requirements, and limited suppliers. However, by managing our deployments personally and sourcing materials from recycled and open-source resources, the resulting systems is substantially below market price while providing modern features left missing on most off the shelf solutions.

Environmental Hazards

The extreme oceanic conditions can pose a design and testing challenge. However, by utilizing recycled materials - specifically, robust FAD buoys initially built for these conditions - we bypass many of these challenges, saving both time and resources.

Post Proceessing

The sheer volume of data generated from marine monitoring systems can be overwhelming. We address this by employing open-source tools like OpenCV and FFmpeg to post-process our data in parallel with data capture. This provides summary statistics and feature extraction that considerably reduce the time spent reviewing extensive video, audio, and numerical data.

Delayed Feedback

Traditional remote marine monitoring typically uses data loggers that require device retrieval which adds significantly operational...