Author ORCID Identifier
Anson Hines: 0009-0004-7627-7206
Margaret Kramer: 0009-0000-3793-2547
Kimberly Richie: 0000-0002-8535-9420
L. David Smith: 0009-0001-4760-8078
Matthew Ogburn: 0000-0001-5417-555X
Gregory Michael Ruiz: 0000-0003-2499-441X
Document Type
Article
Publication Date
3-16-2026
Publication Title
PNAS
Abstract
This 37-y record (1989–2025) of field experiments tested seasonal and annual variation in predation on juvenile blue crabs (Callinectes sapidus) in a representative mesohaline site of Chesapeake Bay, USA, where the species is a dominant epibenthic predator and major fishery. We used replicated sets of individually tethered crabs to provide a relative index of lethal and sublethal predation rates on intermolt individuals as a function of size and habitats. Cannibalism by large adult crabs accounted for>97% of predation of juvenile crabs; predation by fish was not observed; and mortality from physiological stress was rare (< 1%). Sampling by depth showed that juveniles occurred in nearshore shallows, while adults were in deeper water. Cannibalism was also depth-dependent: Rates were high at 75 cm depth; intermediate at 40cm; and lowest at 15 cm shallows, which provided partial refuge. Cannibalism was size-dependent: 30 to 50 mm juveniles experienced high rates of predation; 90 to 110mm preadults had low rates; and >120 mm adults had no predation. Cannibalismr ates on juveniles varied seasonally, peaking during summer when adult crabs were most active; no tethering predation occurred in cold months. Variation in adult crab abundance accounted for 51% of annual variation in predation on tethered juveniles.Cannibalism by adult blue crabs provides a density-dependent regulation of juveniles by adults, with juvenile survivorship dependent on shallow-water refuge habitats int he mesohaline zone of the estuary. The refuge habitat appears increasingly restricted both by predatory fish common in high and recently introduced in low salinities, and by shoreline hardening.
Keywords
cannibalism, predation, refuge, blue crab, Chesapeake Bay
Volume
123
Issue
12
First Page
e2533461123
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Rights
© 2026 the Author(s).
Version
Version of Record
Recommended Citation
Hines, Anson H.; Kramer, Margaret A.; Richie, Kimberly D.; Smith, L. David; Aguilar, Robert; Ogburn, Matthew B.; Johnson, Eric G.; and Ruiz, Gregory M., "Cannibalism, Predation, and Refuges of Juvenile Blue Crabsfrom a 37–Year Experiment" (2026). Biological Sciences: Faculty Publications, Smith College, Northampton, MA.
https://scholarworks.smith.edu/bio_facpubs/348