The Trophic Ecology of Clearnose Skates in Delaware Bay Using Stable Isotope Analysis
Date
2024-05
Authors
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Publisher
University of Delaware
Abstract
Clearnose Skates (Rostrorja eglanteria) are abundant off the East coast of the United
States and in Delaware Bay yet are often overlooked and historically understudied. As meso predators, it is crucial to understand the exact role which Clearnose Skates play within
ecosystems, as they have substantial control over food web dynamics. My study aimed to assess
the trophic role of Clearnose Skates in Delaware Bay using stable isotope analyses of carbon,
δ13C, and nitrogen, δ15N. Tissue was collected from Clearnose Skates (n=62) and a variety of
potential prey species (n=39) throughout all regions of Delaware Bay in 2022. Muscle and blood
tissues were analyzed for stable isotope ratios to determine changes in diet temporally, spatially,
sexually, and ontogenetically. Some significant sexual and ontogenetic differences were found,
indicating niche partitioning between mature sexes as well as between immature and mature
skates of the same sex. Spatially, only mature females showed any significant changes in δ15N
values. Through characterization of sexual and ontogenetic changes in diet, my study provides
valuable insight into the trophic role of Clearnose Skates in Delaware Bay, with implications for
local recreation and management.