RV Corella Fisheries Laboratory cooperated with the Admiralty Research Laboratory to identify fish detected by long-range sonar equipment installed at the Admiralty Experimental Station, Perranporth. The RV "Corella" was directed from the shore to an area some 65 km distant, that was returning a strong and extended echo. The "Corella" was able to correlate this target with shoals detected on a conventional echo sounder, and substantial catches of sprats were taken in the area using a midwater trawl. The RV "Corella" was used throughout the 1970s for pioneering studies on fish migration. Individual plaice ("Pleuronectes platessa") fitted with 300 kHz acoustic transponding
Flatfish as an early relative of the flatfish and transitional fossil. In a typical modern flatfish, the head is asymmetric, with both eyes on one side of the head. In "Amphistium", the transition from the typical symmetric head of a vertebrate is incomplete, with one eye placed near the top of the head. The researchers concluded, "the change happened gradually, in a way consistent with evolution via natural selection—not suddenly, as researchers once had little choice but to believe." Flatfishes have been cited as dramatic examples of evolutionary adaptation. Richard Dawkins, in "The Blind Watchmaker", explains the flatfishes' evolutionary history thus: