MYTAG: Integrating natural and artificial tags to reconstruct fish migrations and ontogenetic niche shifts

Fish migrations are a fundamental concern in marine biology, still triggering scientific curiosity and technological challenges. Reconstructing migration pathways throughout fishes’ life cycle is fundamental to understand population dynamics, fishes’ resilience to harvest and ultimately design effective management and conservation plans. Despite multiple efforts in the last decades combining innovative techniques and approaches, studying individual fish movements remains a challenge and is a new and exciting field of application of technological innovation to marine sciences.
MYTAG will use state of the art techniques to integrate natural and artificial markers to study fish reproductive migrations, estuarine colonization and nursery habitat use of a model species, the European flounder (Platichthys flesus). Flounder is a species that migrates along the river-estuary-sea continuum throughout its life-history, with adults migrating offshore to spawn and early life-stages as larvae and juveniles migrating into coastal or estuarine habitats. The innovative aspect of this project is the integration of both natural and artificial tags and the development and application of new technological solutions for tracking marine fish populations using autonomous surface vehicles (ASVs). The project starts by a preliminary experimental work in the laboratory and in the field to test the effects of acoustic markers and external tags on fish behaviour, condition and survival. A strategically designed field work approach will reconstruct life-history migrations using natural markers, as otoliths and gonads. New technological approaches for direct tracking of fish movements over the river-estuary-sea continuum will be firstly developed on laboratory trials, and later in the final marine tracking experiment. Selected artificial tags will be applied to fish, including external tags for mark-and-recapture experience and acoustic tags to be tracked by ASVs to disclosure the species’ major life-history events, as spawning migrations, estuarine nursery colonization and differential habitat use. MYTAG implements a new multi-tag approach and innovative techniques applicable to many species worldwide, improving the efficacy of management and conservation strategies, allowing also for the opportunity of new technological innovation.