We propose a new approach based on the use of many data collectors, which we designate Mini-Sinks (MSs), instead of a single sink in order to improve Wireless Sensor Network (WSN) performances. One or more MSs are mobile and move according to an arbitrary mobility model inside the sensor field in order to maintain a fully-connected network topology, collecting data based on the controlled Energy Conserving Routing Protocol (ECRP) within their coverage areas and forwarding it towards the single main sink. ECRP, based on route diversity, is implemented in MSs and sensors in order to optimize the transmission cost of the forwarding scheme. A set of multiple paths between MSs and sensors is generated to distribute the global traffic over the entire network. Simulations were performed in order to validate the performance of our new approach. We compare the results obtained with those for a single static sink and mobile sink, and show that our approach can achieve better results in terms of packet delivery ratio, throughput, end-to-end delay and multiple paths overhead.