Data From: Shortened food chain length in a fished versus unfished coral reef

# Shortened food chain length in a fished versus unfished coral reef [https://doi.org/10.5061/dryad.kprr4xhcg](https://doi.org/10.5061/dryad.kprr4xhcg) This dataset compares the trophic position between a lightly fished (Tabuearan) and an unfished (Palmyra) atoll in the Line Islands chain. The bulk of the manuscript focuses on analyses of natural abundance isotopic data from seven species across a range of trophic positions. To better control for shifting baselines compound-specific stable isotope analyses are performed on one species (grey reef shark) across the two islands, using multiple different approaches to estimate trophic position for this species. To highlight the fact that the reefs are otherwise similar we also provide data on reef structure and cover (e.g. % live coral, % algae, rugosity). To highlight the effects that fishing has had on fish communities and the potential for these shifts to explain differences in trophic data, we also provide biomass data on fish communities across these sites. ## Description of the data and file structure This data is described in full in the manuscript: Shortened food chain length in a fished versus unfished coral reef. ### **Natural\_abundance** Includes the bulk isotope values (delta values, ‰) of carbon (δ13C) and nitrogen (δ15N) as determined at the Stanford Stable Isotope Biogeochemistry Facility using a Carlo Erba/ConFlo II elemental analyzer Thermo-Delta Finnigan Delta-Plus IRMS. * Island is Tabuearan (TAB) or Palmyra (PAL). * Species is the species of organism from which tissues were collected, using the following abbreviations: *Porites lutea* (POLU), *Acanthurus nigricans* (ACNI), *Lutjanus flubus* (LUFL), *Cephalophis argus* (CEAR), *Caranx melampygus* (CAME), *Carcharhinus galapagensis* (CAGA), *Carcharhinus amblyrhynchos* (CAAM). * Type indicated the trophic groupings used in analyses and includes top predators (top), mesopredators (meso), and basal species (basal). * For individuals where individual ID was recorded that ID was given in ind_ID. * When size was recorded and used in analyses that is recorded in cm as body_size. d13 and d15N are the bulk isotope (values of carbon (δ13C) and nitrogen (δ15N) ‰. ### **CSSIA\_data** Includes the compound-specific amino acid analyses used in this manuscript for 11 individuals of *Carcharhinus amblyrhynchos*. Each row is a unique individual. * Island is Tabuearan (TAB) or Palmyra (PAL). * Glu-Gly is the difference between Glutamine and Glycine. * TAA_SAA is the difference between the average of all putative TAAs (Glu, Ala, Val, Leu, Pro, Asp) vs the average of both putative SAAs (Phe and Gly). * TAA-Gly is the difference of average TAAs compared with Glycine. ### **Fish biomass** Data for the average biomass per day per transect (kg per 1000 m^2). * Island is Tabuearan (TAB) or Palmyra (PAL). * Site is the name of the survey site. * Feeding guild is the species in the trophic classification of either predator (F), herbivore (H), invertivore (I), or planktivore (P). * Biomass_day is the average biomass per day per transect (kg per 1000 m^2). ### **Benthic cover** Shows the average cover across each of the 10 quadrats per site broken down by type of cover. * Island is Tabuearan (TAB) or Palmyra (PAL). * Site is the name of the survey site. * Cover type is the grouping of cover types. * Cover is the average percent cover per transect of this coral type. Given observer error total cover for each cover class value can go slightly over 100. ### **Rugosity** * Rugosity: A rugosity index calculated by laying a 2m chain against the reef surface and measuring the distance between two endpoints; the ratio of the length of this chain as laid against the reef surface to the actual length of the chain was the rugosity index. * Island is Tabuearan (TAB) or Palmyra (PAL). * Site is the name of the survey site.