Number of the records: 1
Vertical distribution of alewife in the Lake Ontario offshore: Implications for resource use
- 1.
SYSNO ASEP 0480484 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Vertical distribution of alewife in the Lake Ontario offshore: Implications for resource use Author(s) Říha, Milan (BC-A) RID, ORCID
Walsh, M. G. (US)
Connerton, M. J. (US)
Holden, J. (CA)
Weidel, B. C. (US)
Sullivan, P. J. (US)
Holda, T. J. (US)
Rudstam, L. G. (US)Number of authors 8 Source Title Journal of Great Lakes Research. - : Elsevier - ISSN 0380-1330
Roč. 43, č. 5 (2017), s. 823-837Number of pages 15 s. Language eng - English Country US - United States Keywords diel vertical migration ; deep chlorophyll layer ; zooplankton ; mysids ; alewife Subject RIV DA - Hydrology ; Limnology OECD category Marine biology, freshwater biology, limnology R&D Projects LD15021 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support BC-A - RVO:60077344 UT WOS 000411533900006 EID SCOPUS 85027156718 DOI 10.1016/j.jglr.2017.07.007 Annotation Oligotrophication of Lake Ontario has led to increased water clarity and an increased proportion of zooplankton residing in the metalimnion during the day, which may affect the utilization of different depth regions for planktivorous fish. We investigated day and night distributions of fish using hydroacoustics and suspended vertical gillnets during the summer of 2013 when a deep chlorophyll layer (DCL) was established. We related fish distributions to concurrent measures of temperature and prey (zooplankton) density. Alewife dominated in vertical gill net catches, indicating that most acoustic targets were alewife. Alewife schooled during the day in the bottom of the mixed layer, and at dusk alewife schools broke up and fish moved towards the surface. We hypothesize this movement followed migrating zooplankton to allow feeding at night, alewife sampled from vertical gillnets fed on cyclopoid copepods and cladocerans, prey groups that migrate into the epilimnion at night. Some alewife remained at the bottom of the mixed layer at night and these fish ate deep-water calanoid copepods such as Limnocalanus. Vertical distributions were best predicted by temperature and the interaction between temperature and zooplankton density. We include uplooking acoustics data to complement our downlooking datasets, which provided evidence for potential bias in downlooking acoustic assessments of alewife due to high proportions of alewife found in the surface exclusion zone. Our approach combining several datasets provides a new perspective to understand summer diel distribution of alewife and the factors driving their distribution. Workplace Biology Centre (since 2006) Contact Dana Hypšová, eje@eje.cz, Tel.: 387 775 214 Year of Publishing 2018
Number of the records: 1