The first four eels were released in May 2000. Two of the tags were programmed to release and ascend after two months, followed by the other two a month later. The data they transmitted included enough daily location data to construct swimming tracks for all four eels. Three of them showed an eastward movement along the Chatham Rise. The data from the fourth eel's tag had a gap for the first three weeks (by which time the eel was in Hawke Bay), but then she swam south, also to the Chatham Rise.

While information from these tags did not shed much light on possible spawning areas, the daily temperature variations indicated the eels were moving significant vertical distances through the water column, and the scientists were able to calculate that they swam 26 to 31km per day.

A second batch of ten eels was released from Te Waihora in May 2001. Tags for these fish included a pressure sensor to record swimming depth. Unfortunately, good information was received from only three of the tags, which stayed attached for periods ranging between 26 to 161 days. One tag surfaced 160km northeast of New Caledonia; indicating the spawning grounds for longfins were in the tropics, something the scientists had assumed but were unable to prove.

As the three eels all swam too deep for the tags to record surface light, scientists were unable to accurately determine their swimming tracks; however, they did obtain some very interesting information on swimming depths. The scientists were surprised to find that all three eels showed regular daily vertical movements through the water column - two of the three frequently swam to depths of 800m or more, with the greatest depth recorded being 980m. Why would migrating eels spend energy on daily dives of many hundred metres? Perhaps to avoid predation, as various sharks, swordfish, and toothed whales are known to make regular dives to similar depths. Even in the tropics, water temperatures encountered by the eels at these depths were only 5-6°C – too low for efficient metabolism. When the eels ascended during the evening to shallower and warmer waters, it was presumably to warm up. So, while the scientists didn't find the spawning grounds of longfins, they did obtain very interesting information on swimming speeds, depths and behaviour of migrating eels.

In May 2006, three more eels were released from the outlet of Lake Ellesmere. All three tags are due to ascend in early December. The scientists hope that the eels will show some consistency in swimming direction, and converge on the possible spawning area.