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Seasonal dynamics in a nearshore isotopic niche and spatial subsidies from multi-trophic aquaculture

journal contribution
posted on 2023-05-19, 14:54 authored by Christine WeldrickChristine Weldrick, Jelinski, DE
A poorly understood food web dynamic concerns possible seasonal variation in spatial subsidies associated with multi-trophic aquaculture and their effects on extractive and naturally occurring organisms. We used the stable isotopes δ13C and δ15N and circular statistics to investigate niche overlap across a year-long period at an experimental multi-trophic aquaculture facility in British Columbia, Canada. A two-source mixing model revealed that particulate organic matter was the most important food source for all sample invertebrates (mean range 40%–98%) compared with farm effluent (mean range 3%–35%). There were significant month-to-month changes in δ13C and δ15N for all species except for the brooding transparent tunicate (Corella inflata). We did not detect any directionality for the entire community, but did identify variable directional shifts for each species, suggesting resource partitioning driven by competition and (or) morphology-based differences in feeding strategies. This was further supported by seasonal variation in inter- and intraspecific isotopic niche widths. Isotopic niche overlap among co-occurring invertebrates appeared to be stronger during winter and summer than autumn months. Our study provides valuable insights on the role of multi-trophic derived effluent on a nearshore marine community composed of both natural and cultured species within the same feeding guild.

History

Publication title

Canadian Journal of Fisheries and Aquatic Sciences

Volume

74

Issue

9

Pagination

1411-1421

ISSN

0706-652X

Department/School

Institute for Marine and Antarctic Studies

Publisher

Natl Research Council Canada

Place of publication

Research Journals, Montreal Rd, Ottawa, Canada, Ontario, K1A 0R6

Rights statement

Copyright the Authors 2016.

Repository Status

  • Restricted

Socio-economic Objectives

Fisheries - aquaculture not elsewhere classified

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