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
RV Platessa RV "Platessa" was handed back to the Ministry of Defence (United Kingdom) after 20 years in service, she was replaced by the "RV Corella". In 1968 the RV "Platessa" was sold to private owners (H.J. Lamprell Ltd) and after sinking in Hamilton Dock, Lowestoft in 1975 she was eventually hulked at Lake Lothing where her remains lay for many years. She was recorded as still extant in Lake Lothing on August 19th 2015, and from examination of Google Earth images it seems that she continues to exist as one of two wooden wrecks (the other being the MFV Yellowtail) in