Aquaculture
Fish farming technology, monitoring systems and unmanned equipment.
Aquaculture is the controlled production of aquatic animals and plants, and it now supplies a large share of the seafood people eat. For anyone working subsea, the engineering interest sits in marine finfish and shellfish farming, where the production unit is moored in open water and has to be built, monitored, cleaned, and inspected in conditions closer to offshore work than to farming.
Three production models dominate, and each imposes different problems. Open net pens in sheltered coastal water are the cheapest to build and the most exposed to whatever the surrounding environment does to them: currents, storms, plankton blooms, parasites, and escapes. Recirculating systems move the operation onshore into tanks with mechanical and biological filtration, which buys full control of temperature and water quality at the cost of high capital spend and total dependence on pumps, oxygen supply, and alarms. Offshore and submersible pens try to get the volume and water exchange of open water while surviving higher-energy sites, and they push mooring design, structural fatigue, and remote operation to the front of the problem.
Feed is the largest running cost and mortality is the largest source of lost value, so most of the technology on a modern site exists to watch those two things. Underwater cameras track pellet fall and feeding response so that feeding stops before food passes through the pen. Sensor strings measure dissolved oxygen, temperature, salinity, and current at several depths, because a stratified water column can put a whole pen under stress within hours. Biomass estimation systems size and count fish optically or acoustically to inform harvest timing.
The subsea equipment is largely inherited from offshore energy. Small observation vehicles handle net integrity checks and mortality retrieval, remote rigs clean netting in place, and moorings and anchors need periodic inspection like any other submerged structure. Buyers in this sector weigh biosecurity between sites, the sea states gear must actually work in, and the environmental monitoring a licence obliges them to carry out.
The Most-Caught Fish in the World
Anchoveta at 4.9 million tonnes, Alaska pollock at 3.4 and skipjack tuna at 3.1. The top three have not changed since 2010, and most of the first one is not eaten by people.
How Dependent Is the World on Aquaculture?
In 2022 farmed aquatic animals overtook wild capture for the first time, at 94.4 million tonnes and 51 percent of the total. What that crossover actually means.
What Subsea Research Brought to Fish Farming
Sensors, vehicles and positioning developed for offshore energy and ocean science now run inside fish farms. What transferred, and what had to be rebuilt.
Unmanned Equipment in Aquaculture
Resident cleaning robots, autonomous net inspection and the move offshore. Where uncrewed systems have taken over fish farm work, and where divers remain.
The Technology Running Modern Fish Farms
Camera systems counting sea lice on 100 fish a day, laser delousing, biomass estimation and net inspection robots. The instrumentation inside a working fish farm.