Role of buoyancy in shaping species-specific spatial niches during early stages of fish

Abstract

The spatial distribution of marine fish eggs and larvae reflects how biological traits interact with oceanography. Despite developing in a highly dispersive environment, early life stages often display persistent and species-specific spatial patterns, observations that are difficult to explain by behavioural processes alone. This essay explores the idea that buoyancy in this context acts as a key physical process linking eggs and larvae to conservative water-mass properties as salinity and temperature. Species- and population-specific buoyancy characteristics may restrict early life stages to limited three-dimensional habitats, help maintain species-specific spatial associations with hydrographic structures, and bias drift routes towards recurrent nursery areas. The proposed key role of salinity has implications for how climate-driven changes would propagate through early stages and affect recruitment to fish stocks.