Since the discovery of European carp (Cyprinus carpio) in Lakes Crescent and Sorell in 1995, intense, physical removal techniques were implemented. As a result, carp were successfully eradicated from Lake Crescent, while approximately 3% of the carp population in Lake Sorell remains. A key factor to the success of both lakes has been the use of radio transmitter implanted carp; “Judas fish”. This technique was first incorporated into the Carp Management Program (CMP) in 1997, where mature male carp were initially used as the hosts for transmitters. The data collected gave the CMP an insight into seasonal habitat preference, which resulted in the detection of spawning aggregations. Aggregations were targeted using an integrated approach, with the combined use of gill nets and electrofishing. After almost eradicating carp (<50) from Lake Sorell, a spawning event occurred in 2009 leading to the unfortunate recruitment of approximately 50 000 carp. Consequently, juvenile carp were implanted with radio-transmitters to detect any aggregations, which were mainly associated with feeding. These juvenile 1 to 2 year old carp were found to frequent warm shallows, and were thus vulnerable to effective targeting. However once reaching 3 years of age, they moved out into deeper water. The maturity of these fish was slower than any other cohort of fish observed since the start of the CMP. Thus over the next few years, the delayed maturity resulted in the carp avoiding the shallows for the majority of time, and subsequently led to significantly lower catch per unit effort (CPUE) due to fewer opportunities to target aggregations. If these fish reach maturity this coming season in conjunction with ideal environmental cues (rising lake levels and warm settled weather in spring), it is likely that they will push back inshore and become susceptible to targeted effort.