Filial cannibalism leads to chronic nest failure of eastern hellbender salamanders (Cryptobranchus alleganienesis)

These data and code support the results in our accompanying manuscript. In
species that provide parental care, parents will sometimes cannibalize
their own young. Here, we quantified the frequency of whole-clutch filial
cannibalism in a species of giant salamander (eastern
hellbender; Cryptobranchus alleganienesis) that has experienced
precipitous population declines with unknown causes. We used underwater,
artificial nesting shelters deployed across a gradient of upstream forest
cover to assess the fates of 182 nests at 10 sites over 8 years. We found
strong evidence that nest failure rates increased at sites with low
riparian forest cover in the upstream catchment. At several sites,
reproductive failure was 100%, mainly due to cannibalism by the caring
male. The high incidence of filial cannibalism at degraded sites was not
explained by evolutionary hypotheses for filial cannibalism based on adult
body condition or low reproductive value of clutches. Instead, larger
clutches at degraded sites were most vulnerable to cannibalism. 
We hypothesize that high frequencies of filial cannibalism of large
clutches in areas with low forest cover could be related to changes in
water chemistry or siltation that influence parental physiology or that
reduce viability of eggs. Importantly, our results identify a possible
mechanism contributing to population declines and observed geriatric age
structure in this imperiled species.