Quantifying spatio-temporal consistency in the trophic ecology of two sympatric flatfishes

Hunt, G. L., Cobain, M. R. D., McGill, R. A. R. , Pinnegar, J. K., Engelhard, G. H., Wigham, B. D. and Polunin, N. V. C. (2023) Quantifying spatio-temporal consistency in the trophic ecology of two sympatric flatfishes. Journal of Fish Biology, 103(2), pp. 378-392. (doi: 10.1111/jfb.15458) (PMID:37213138)

Abstract

Sympatric flatfish predators may partition their resources in coastal environments to reduce competition and maximise foraging efficiency. However, the degree of spatial and temporal consistency in their trophic ecology is not well understood because dietary studies tend to overlook the heterogeneity of consumed prey. Increasing the spatial and temporal scale of dietary analyses can thus help to resolve predator resource use. We applied a stomach content and multi-tissue (liver and muscle) stable isotope (δ13C, δ15N and δ34S) approach to investigate the feeding habits of two co-occurring flatfish predators, common dab (Limanda limanda) and European plaice (Pleuronectes platessa), across four bays on the Northumberland coast (UK) over short (hours), medium (days) and long (months) temporal scales. Stomach content analyses showed spatial consistencies in predator resource use, whereas stable isotope mixing models revealed considerable inter-bay diet variability. Stomach contents also indicated high dietary overlap between L. limanda and P. platessa, while the stable isotope data yielded low to moderate levels of overlap, with cases of complete niche separation. Furthermore, individual specialisation metrics indicated consistently low levels of specialisation among conspecifics over time. We document changes in resource partitioning in space and time, reflecting diet switching in response to local and temporal fluctuations of patchily distributed prey. This study highlights how trophic tracers integrated at multiple temporal and spatial scales (within tens of kilometres) provide a more integrative approach for assessing the trophic ecology of sympatric predators in dynamic environments.

• Item Type: Articles
• Additional Information: G.L.H. was supported by a Newcastle University SAgE DTA studentship with additional funding support from a Cefas Seedcorn grant (DP371T). Stable isotope analysis funding was provided by a NERC LSMSF Grant EK320-07/19. M.R.D.C. was supported by an Irish Research Council Laureate Award IRCLA/2017/186 to Andrew L. Jackson, Trinity College Dublin.
• Keywords: Sympatric, trophic ecology, stable isotopes, stomach contents, coastal, flatfishes.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: McGill, Dr Rona
• Authors: Hunt, G. L., Cobain, M. R. D., McGill, R. A. R., Pinnegar, J. K., Engelhard, G. H., Wigham, B. D., and Polunin, N. V. C.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Journal of Fish Biology
• Publisher: Wiley
• ISSN: 0022-1112
• ISSN (Online): 1095-8649
• Published Online: 22 May 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Journal of Fish Biology 103(2):378-392
• Publisher Policy: Reproduced under a Creative Commons license