A close-up on how in-situ sensors can support sustainable fisheries management and broader ocean protection

Traditionally, fisheries managers have had to make do with limited data on the ocean conditions their livelihoods depend on. With only periodic sampling trips and lab analysis that could take days or weeks to process, problems might be detected only after fish stocks have been compromised or harmful conditions have gotten worse.

In-situ sensors are turning the tide on that challenge by delivering continuous, real-time data from the ocean itself. These technologies can monitor everything from water quality and ecosystem health to fish behavior, bringing powerful 24/7 visibility to fisheries and ocean protection efforts alike. 

What are in-situ sensors?

In-situ (meaning “in place”) sensors observe the ocean directly — on buoys, gliders, research vessels, and others — to measure conditions like temperature, salinity, pH, currents, nutrients, pollutants, and acoustic signals. 

Specialized types of in-situ sensors include: 

• Acoustic sensors use sound waves that travel long distances underwater. Active devices send out sound pulses and analyze the echoes to map the seafloor and locate fish, while passive sensors listen for sounds from marine animals like whales.
• Optical sensors measure how light interacts with seawater to determine water clarity, detect pollutants, and track plankton. They’re used in applications ranging from aquaculture to oil spill detection in both shallow and deep ocean waters. 
• Chemical sensors detect dissolved substances like nutrients, gases, and pollutants in the water. They can help scientists monitor ocean health, track biogeochemical cycles, and identify contamination in real time.

In-situ sensors may be deployed individually or as part of advanced networks, helping provide ground-truth data that validates models and satellite observations.

How in-situ sensors support sustainable fisheries

In-situ sensors can support Marine Protected Areas (MPA) management and sustainable marine ecosystems with fishery monitoring, reef and estuary conservation, and ecosystem health understanding. They serve as decision support tools across multiple scales — from individual vessels to fleet-wide operations and coastwide monitoring networks — enabling timely action in both routine management and emergency situations.

For example, UK-based CatchCam Technologies demonstrates how sensors enable more selective fishing practices. Its underwater camera systems and advanced sensors help fishers see what they’re catching in real time and adjust methods to avoid unwanted species. The company has deployed across European waters, improving sustainable wire-trap fishing for European perch in Finland, enhancing pot-caught scallop fishing in Ireland, and increasing catch efficiency of seine-net fishing for squid and groundfish in Scotland.

In-situ sensors also provide the broader environmental context that informs where and when to fish. As part of the Fishing Vessel Ocean Observing Network (FVON), US-based company Ocean Data Network deploys environmental sensors that provide fishers with real-time data on climate and weather variables to inform catch decisions and support fish stock management. The Moana Project in New Zealand, Marport, and others demonstrate the growing diversity of this category, with vessel-based sensors becoming increasingly common tools for sustainable fishing operations worldwide.

At the coastwide scale, sensors monitor threats that affect entire regions. In the Pacific Northwest, for instance, NOAA deploys toxin sensors that measure harmful algal bloom levels in near real-time, helping officials make critical calls about shellfish harvest closures as well as public health.

Where in-situ sensors are gaining traction

Modern sensors use sophisticated data transmission — acoustic signals underwater, satellite or cellular networks at the surface — with solar-powered systems enabling months-long deployments. These advances have made widespread adoption practical. And advancing technology is only fueling more momentum, with the marine IoT market projected to nearly triple in less than a decade.

Today, sensor networks span global ocean observing programs from the Arctic to the Southern Ocean. Expansion has been steady over the last two years, with networks increasingly connecting to coordinated international efforts like the Intergovernmental Oceanographic Commission’s Global Ocean Observing System (GOOS).

As of late last year, GOOS reports 64 contributing countries, 17 global ocean observing networks, 9,389 ocean observing platforms, and 120,000+ ocean observations per day — all contributing to a sophisticated global ocean intelligence system. 

Powering the future of ocean stewardship

In-situ sensors are enabling a whole new level of proactive fisheries management. With near-continuous data, managers can make decisions before issues or outright crises develop, and leave the guesswork behind as they chart next steps.

Real-time ocean intelligence empowers both conservation and fishing communities: healthier oceans support more productive fisheries. And thanks to in-situ sensors, the data to achieve both is increasingly within reach.

To learn more about how these and other emerging technologies are supporting ocean protection, read the report.