Fish hate us

Information from the ocean via space to tuna vessels

"Fish Hate Us" is the catchy headline of a website by a New Zealand software developer that specialises in 3D mapping of the ocean floor. Together with sensors on the trawl nets and sonar it has transformed the bottom trawl industry into a commercial "video game". Their slogan captures state of the commercial fishing industry, as well as the attitude of many in it.

"Becoming 'out of favour' with the fish and making more money has never been this easy", proclaims the website. And what's ever wrong with easy money?

Obviously, taking too many fish out of the sea, while good for short-term profits, has in many places led to fisheries collapse ruinous for everyone - fishermen, marine mammals, consumers and future generations. To avoid this, ideally government regulators keep fish populations at safe levels - and for that they need to figure out how many fish are left in the sea. There are a number of ways they try to do this, but one of the primary and most common measures they have is the amount of fish caught per effort expended. If it takes more (or an equal amount of) effort to catch less fish then there's a problem.

Obviously, increases in efficiency is one of the many factors that has to be taken into account. But, as is common in almost all industries, fisheries policy makers can't keep up with the pace of technological innovation - especially when it comes to information gathering, processing and communication. This is by no means the only (or biggest) factor contributing to fisheries mismanagement. Still, it's one that a lot of people overlook because they wrongly stereotype fishermen as technologically unsophisticated.

Now let's review some of that technology helping the fishermen find fish:

Fish sonar
Anyone who's watched "Das Boot" knows that sonar has been around since WWII, but improvements in ease of use and resolution make current models a far cry from their U-boat hunting ancestors. Operating in the neighbourhood of 28, 50 and 200 KHz, modern omni-directional scanning sonar can present a fairly accurate picture of what's going on under the surface to a range of over 1,500m. On the top end, the Simrad SP90 is a dedicated low frequency long range tuna sonar that has a 3,000m range.

Data provided includes direction, distance and depth of targets, fish school amount, tidal current, water depth and water temperature. Units can typically interface with the ship's GPS using NMEA standard data, allowing integration of ship's position, speed and course. An alarm can be set to sound for fish schools over a specified size.

In addition to technical improvements, there has also been a massive drop in price of sonar units, leading to...

Buoys with Sonar
Zunibal SL, based near Bilbao in northern Spain, is a market leader in satellite-based fish-finding services. The company supplies its products and services to hundreds of tuna fishing vessels worldwide, with a large percentage of its customer base operating in the Pacific. Zunibal's principal product is its Tunabal buoy, which is typically carried by tuna fishing boats. Each buoy is equipped with a solar-powered satellite communicator and an echo-sounder fish-finding system. The buoys are released by fishing vessels during their voyage and drift along ocean currents, tending to congregate in areas of high plankton concentration, which also represent good feeding grounds for fish.

When a Tunabal buoy detects the presence of a shoal of fish, it transmits the location - together with information about drift direction, speed and water temperature - back to the fishing vessel's skipper. Zunibal's service can therefore contribute to the speed and efficiency with which a fishing vessel can locate its catch, with resultant savings in time at sea and fuel consumption.

To transmit the data, Zunibal uses Satamatics Ltd., a specialist supplier of satellite-based telemetric information services. Satamatics' global telemetric service allows position tracking and two-way messaging, as well as status monitoring and control of remote assets and installations. For transmission hardware, the company uses the Inmarsat D+ system.

Satellite surveillance
In 1997, the OrbView-2 spacecraft (a.k.a. SeaStar) was launched. OrbView-2's only scientific instrument is the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS).

The data gathered will be used to look at oceanic factors affecting global change, and learn more about the oceans' role in the global carbon cycle - plus other biogeochemical cycles. Observations of ocean colour are used to establish the depth that photosynthesis can occur at, the abundance and distribution of plant pigments, and the concentration of coloured dissolved organic carbon.

Tuna and sardine purse seiners, pelagic longliners, trolling vessels and mid-water trawling vessels throughout the world use a combination of this plankton data and other environmental information to help find the fish they are looking for (marketed as Orbimage's SeaStar Fisheries Information Service).

Another system, created by the French giants CLS - which developed the Argos VMS (Vessel Monitoring System) that is widely used in regional fishing agreements to monitor licensed vessels - teamed with Thalos, is called CatSat. This software product uses data from the European Space Agency's ERS-1 and ERS-2 satellites, and the ENVISAT mission as well as TOPEX/POSEIDON satellite (a joint NASA-CNES altimetric mission) and its follow-on JASON-1. The oceanographic data is used in the pelagic fisheries by seiners, trawlers, longliners and pole and line vessels.

Orbimage and CatSat both provide valuable information and data to unravel the role and function of the oceans for the benefit of the Earth environment. Both systems could (and should) also contribute to the management of sustainable and fair fisheries. They have a natural responsibility to help prevent their technology from contributing to the collapse of fisheries - through overfishing or pirate fishing. After all, when there are no more fish to catch the commercial value of their product will be greatly reduced.