Accelerating the Onset of Pisciovery - Intersection of Predator and Prey Phenologies

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Journal or Book Title

Journal Of Fish Biology


Piscivorous fishes tend to be able to consume other fishes early in development and generally experience a dramatic increase in growth after the ontogenetic diet shift to piscine prey. Hence, an acceleration of the onset of piscivory may be favoured strongly by natural selection. Temperate freshwater piscivores, for example, becomes piscivorous at a relatively young age by spawning in advance of, and thereby achieving a size advantage over, the young of their piscine prey. Research in various North American estuaries suggests that young-of-the-year (YOY) bluefish Pomatomus saltatrix, an offshore-spawning estuarine-dependent marine fish, may accelerate the onset of piscivory by being advected to higher latitudes and timing their estuarine entry with the appearance of small coastal fishes. This hypothesis was tested by: (i) determining the annual recruitment date of YOY bluefish and their prey; and (ii) examining the diet and prey size preferences, and predator size-prey size relationships, of YOY bluefish in two different estuarine systems: Great South Bay, and the lower Hudson River. Results suggest that the relationships between bluefish and their prey are determined by a complex interplay between recruitment timing of both predator and prey, prey size availability, predator selectivities, and the timing of vernal warming. It is concluded that YOY bluefish migration into northern estuaries at an advanced size provides them with a predatory size advantage over their principal piscine prey thereby facilitating an early diet shift to piscivory white minimizing the time spent as planktivores.






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