The discovery, last month, by Alaska resident Mike Makar, of an ocean-research drift bottle that had been wandering the Pacific since 1966, the year "Star Trek" debuted on TV and all phones had dials and plugged into a wall, reminds us of a time when tracking ocean currents and the fish that swim in them was pretty low tech, but the best at the time..
The bottle itself, an unassuming vessel about eight inches long, contained a survey form about the bottle's location from the now defunct Bureau of Commercial Fisheries, then part of the U.S. Fish and Wildlife Service and now known as NOAA Fisheries.
The bottle finder's family contacted NOAA Fisheries' Northwest Fisheries Science Center in Seattle, the facility that conducted the original drift-bottle research from the late 1950s through the 1970s. A bit of sleuthing at the center revealed that the bottle was one of almost 10,000 released during that period to track ocean currents and fish migration.
The bottle was released near Nushgash Bay, in Bristol Bay north of the Aleutian chain and was found in Cold Bay, about half-way along the Aleutian chain's southern coast. That's a distance of less than 300 miles as the crow flies, but where the bottle traveled during its 47 years at sea, like some miniature Flying Dutchman, is impossible to know.
Using new technologies, NOAA scientists today use a variety of ocean current and fish tracking methods. Unlike the drift bottle in which success depended upon the kindness of strangers, modern technologies use satellite tags, fixed current profilers and other instruments using satellite communication links to relay important data instantly to laboratories onshore.
One of the oldest tracking methods involves tagging young salmon with tiny coded wires before they enter the ocean as juveniles and then recovering the fish – and their unique tags – when they return to freshwater to spawn as adults. Coded-wire tagging has been going on for almost 40 years and has been used on over 1 billion salmon. The wealth of information from the roughly 200,000 adult salmon that are recovered every year is invaluable in helping management and recovery of these fish.
More recently developed tags can record vital information like water temperature, depth, date and day length (to estimate a fish's location). Scientists have to recover these tags to download the data, but they can obtain several years' information about temperature preferences and diving behavior and location of fish.
Another valuable high-tech tag is the acoustic tag, which works by transmitting a unique code that can be "heard" and recorded by receivers, tracking an individual fish wherever it goes for several months. Such tags, and the fish that carry them, don't need to be recovered, since it's the receivers, not the tag, that record that data. Numerous receivers deployed in an array along the West Coast have recorded many tagged fish, including species such as white sturgeon that was once thought to make limited migrations, and has since been found to travel hundreds or thousands of miles.
Oceanographers, like fish biologists, need to track ocean currents too. They still drop "drifters" into the sea, but unlike the bottles that float on the surface, these drifters consist of a surface buoy and a probe that extends 50 feet or more below the surface. And unlike those old bottles, which depended on serendipity and a thoughtful citizen to retrieve information, a modern drifter can transmit its position, along with such information as sea-surface temperature and the drifter's velocity, to passing satellites more than a dozen times a day. There are at any one time thousands of theses drifters bobbing on the surface of the world's ocean, all of them talking to oceanographers and telling of their own adventures.
Our technology has come long way since the ocean-research drift bottle was set adrift, but what has not changed is the value of technology to tell us the many things we still do not know about our oceans and the animals that call it home.