Overview of the Fish4Knowledge Project.- User Information Needs.- Supercomputing Resources.- Marine Video Data Capture and Storage.- Logical Data Resource Storage.- Software Architecture with Flexibility for the Data-Intensive Fish4Knowledge Project.- Fish4Knowledge Database Structure, Creating and Sharing Scientific Data).- Intelligent Workflow Management for Fish4Knowledge using the SWELL System.- Fish Detection.- Fish Tracking.- Hierarchical Classification System with Reject Option for Live Fish Recognition.- Fish Behavior Analysis.- Understanding Uncertainty Issues in the Exploration of Fish Counts.- Data Groundtruthing and Crowdsourcing.- Counting on Uncertainty: Obtaining Fish Counts from Machine Learning Decisions.- Experiments with the Full Fish4Knowledge Dataset.- The Fish4Knowledge Virtual World Gallery.- Conclusions.