{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T10:25:49Z","timestamp":1773829549529,"version":"3.50.1"},"reference-count":17,"publisher":"The Royal Society","issue":"12","license":[{"start":{"date-parts":[[2017,12,1]],"date-time":"2017-12-01T00:00:00Z","timestamp":1512086400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/royalsociety.org\/journals\/ethics-policies\/data-sharing-mining\/"}],"funder":[{"DOI":"10.13039\/501100012111","name":"Norwegian Institute for Water Research","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100012111","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Norwegian Institute for Nature Research"}],"content-domain":{"domain":["royalsocietypublishing.org"],"crossmark-restriction":true},"short-container-title":["Biol. Lett."],"published-print":{"date-parts":[[2017,12]]},"abstract":"<jats:p>\n            Polar regions are characterized by acute seasonal changes in the environment, with organisms inhabiting these regions lacking diel photoperiodic information for parts of the year. We present, to our knowledge, the first high-resolution analysis of diel and seasonal activity of free-living fishes in polar waters (74\u00b0N), subject to extreme variation in photoperiod, temperature and food availability. Using biotelemetry, we tracked two sympatric ecomorphs of lake-dwelling Arctic charr (\n            <jats:italic>Salvelinus alpinus n<\/jats:italic>\n            = 23) over an annual cycle. Charr activity rhythms reflected the above-surface photoperiod (including under ice), with diel rhythms of activity observed. During the dark winter solstice period, charr activity became arrhythmic and much reduced, even though estimated light levels were within those at which charr can feed. When twilight resumed, charr activity ensued as diel vertical migration, which continued throughout spring and with increasing day length, despite stable water temperatures. Diel activity rhythms ceased during the polar day, with a sharp increase in arrhythmic fish activity occurring at ice-break. Despite contrasting resource use, circannual rhythms were mirrored in the two ecomorphs, although individual variability in activity rhythms was evident. Our data support conclusions of functionally adaptive periods of arrhythmicity in polar animals, suggesting maintenance of a circannual oscillator for scheduling seasonal behavioural and developmental processes.\n          <\/jats:p>","DOI":"10.1098\/rsbl.2017.0575","type":"journal-article","created":{"date-parts":[[2017,12,6]],"date-time":"2017-12-06T10:10:15Z","timestamp":1512555015000},"page":"20170575","update-policy":"https:\/\/doi.org\/10.1098\/crossmark-policy","source":"Crossref","is-referenced-by-count":17,"title":["Freezer on, lights off! Environmental effects on activity rhythms of fish in the Arctic"],"prefix":"10.1098","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2981-5452","authenticated-orcid":false,"given":"Kate L.","family":"Hawley","sequence":"first","affiliation":[{"name":"Norwegian Institute for Water Research (NIVA), Gaustadall\u00e9en 21, 0349 Oslo, Norway"},{"name":"Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, 1432 \u00c5s, Norway"},{"name":"Department of Biosciences, Science Laboratories, Durham University, South Road, Durham, DH1 3LE, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1117-444X","authenticated-orcid":false,"given":"Carolyn M.","family":"Rosten","sequence":"additional","affiliation":[{"name":"Norwegian Institute for Nature Research (NINA), H\u00f8gskoleringen 9, 7034 Trondheim, Norway"}]},{"given":"Thrond O.","family":"Haugen","sequence":"additional","affiliation":[{"name":"Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, 1432 \u00c5s, Norway"}]},{"given":"Guttorm","family":"Christensen","sequence":"additional","affiliation":[{"name":"Akvaplan-niva, Fram Centre, 9296 Troms\u00f8, Norway"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2009-1785","authenticated-orcid":false,"given":"Martyn C.","family":"Lucas","sequence":"additional","affiliation":[{"name":"Department of Biosciences, Science Laboratories, Durham University, South Road, Durham, DH1 3LE, UK"}]}],"member":"175","published-online":{"date-parts":[[2017,12,6]]},"reference":[{"key":"e_1_3_7_2_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1461-0248.2011.01686.x"},{"key":"e_1_3_7_3_2","doi-asserted-by":"publisher","DOI":"10.1126\/science.aaf9793"},{"key":"e_1_3_7_4_2","doi-asserted-by":"publisher","DOI":"10.1177\/074873001129001980"},{"key":"e_1_3_7_5_2","doi-asserted-by":"publisher","DOI":"10.1038\/4381095a"},{"key":"e_1_3_7_6_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cub.2010.01.042"},{"key":"e_1_3_7_7_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2427.2011.02627.x"},{"key":"e_1_3_7_8_2","doi-asserted-by":"publisher","DOI":"10.1046\/j.1095-8649.2003.00101.x"},{"key":"e_1_3_7_9_2","doi-asserted-by":"publisher","DOI":"10.1139\/f99-245"},{"key":"e_1_3_7_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.margen.2013.10.005"},{"key":"e_1_3_7_11_2","doi-asserted-by":"publisher","DOI":"10.1038\/srep24369"},{"key":"e_1_3_7_12_2","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-079X.2007.00511.x"},{"key":"e_1_3_7_13_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.cbpa.2008.07.019"},{"key":"e_1_3_7_14_2","first-page":"1113","article-title":"Seasonal changes in food consumption and growth of Arctic charr exposed to either simulated natural or a 12:12 LD photoperiod at constant water temperature","volume":"48","author":"S\u00e6ther BS","year":"1996","journal-title":"J. Fish Biol."},{"key":"e_1_3_7_15_2","doi-asserted-by":"publisher","DOI":"10.1007\/s10750-015-2588-3"},{"key":"e_1_3_7_16_2","doi-asserted-by":"publisher","DOI":"10.1098\/rspb.2013.0019"},{"key":"e_1_3_7_17_2","doi-asserted-by":"publisher","DOI":"10.1098\/rsos.160791"},{"key":"e_1_3_7_18_2","unstructured":"Hawley KL Rosten CM Haugen TO Christensen G Lucas MC. 2017 Data from: Freezer on lights off! Environmental effects on activity rhythms of fish in the Arctic. Dryad Digital Repository . (http:\/\/dx.doi.org\/10.5061\/dryad.6k294)"}],"container-title":["Biology Letters"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/royalsocietypublishing.org\/doi\/pdf\/10.1098\/rsbl.2017.0575","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/royalsocietypublishing.org\/doi\/full-xml\/10.1098\/rsbl.2017.0575","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/royalsocietypublishing.org\/doi\/pdf\/10.1098\/rsbl.2017.0575","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,2,17]],"date-time":"2021-02-17T14:01:58Z","timestamp":1613570518000},"score":1,"resource":{"primary":{"URL":"https:\/\/royalsocietypublishing.org\/doi\/10.1098\/rsbl.2017.0575"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,12]]},"references-count":17,"journal-issue":{"issue":"12","published-print":{"date-parts":[[2017,12]]}},"alternative-id":["10.1098\/rsbl.2017.0575"],"URL":"https:\/\/doi.org\/10.1098\/rsbl.2017.0575","relation":{},"ISSN":["1744-9561","1744-957X"],"issn-type":[{"value":"1744-9561","type":"print"},{"value":"1744-957X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,12]]},"assertion":[{"value":"2017-09-15","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2017-11-10","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2017-12-06","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}