{"id":371,"date":"2018-07-30T13:05:46","date_gmt":"2018-07-30T11:05:46","guid":{"rendered":"http:\/\/wp.unil.ch\/lakes\/?p=371"},"modified":"2018-07-30T13:05:46","modified_gmt":"2018-07-30T11:05:46","slug":"parasites-or-food-resources-which-one-controls-wild-fish-populations","status":"publish","type":"post","link":"https:\/\/wp.unil.ch\/lakes\/2018\/07\/parasites-or-food-resources-which-one-controls-wild-fish-populations\/","title":{"rendered":"parasites or food resources : which one controls wild fish populations?"},"content":{"rendered":"

 <\/p>\n

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Triaenophorus nodulosus cysts in perch liver (C) JG<\/figcaption><\/figure>\n

New paper in press in Ecology and Evolution: Parasitic versus nutritional regulation of natural fish populations.<\/h3>\n

by our former master’s student Am\u00e9lie Frantz and in collaboration with Jean Guillard.<\/em><\/strong><\/p>\n

Although parasites are expected to affect their host\u2019s fitness, quantitative proof\u00a0for impacts of parasitism on wild populations is hampered by confounding environmental\u00a0factors, including dietary resource.<\/p>\n

In this paper, we evaluate whether the physiological conditions of European perch\u00a0(Perca fluviatilis) in three large peri-alpine lakes (Geneva, Annecy, and Bourget)\u00a0depend on (a) the nutritional status of the juvenile fish, as revealed by stable isotope\u00a0and fatty acid compositions, (b) the prevalence of the tapeworm Triaenophorus\u00a0nodulosus<\/em>, a parasite transmitted to perch through copepod preys, or (c) interactive\u00a0effects of both factors.<\/p>\n

At the scale of lake populations, the deficit in growth and fat storage of juvenile\u00a0perch during their first summer coincides with a high parasite prevalence and also\u00a0a low quality of dietary resource.<\/p>\n

Yet, at the individual level, parasites had no evident effect on the growth of the\u00a0juvenile perch, while impacts on fat storage appeared only at the highest prevalence\u00a0of the most infected lake. Fatty acid and stable isotope analyses of fish tissue\u00a0do not reveal any impact of T. nodulosus on diet, physiology, and feeding\u00a0behaviour of fish within lakes.<\/p>\n

Overall, we found a low impact of parasitism on the physiological condition and\u00a0trophic status of juvenile perch at the end of their first summer. We find instead\u00a0that juvenile perch growth and fat storage, both factors tied to their winter survival,\u00a0are under strong nutritional constraints.<\/p>\n

However, the coinciding nutritional constraints and parasite prevalence of perch\u00a0juveniles in these three lakes may result from the indirect effect of lake nutrient\u00a0concentrations, which, as a major control of zooplankton communities, simultaneously\u00a0regulate both the dietary quality of fish prey and the host\u2013parasite encounter\u00a0rates.<\/p>\n

So Nutrition wins!<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

  New paper in press in Ecology and Evolution: Parasitic versus nutritional regulation of natural fish populations. by our former master’s student Am\u00e9lie Frantz and in collaboration with Jean Guillard. Although parasites are expected to affect their host\u2019s fitness, quantitative proof\u00a0for impacts of parasitism on wild populations is hampered by confounding environmental\u00a0factors, including dietary resource. … <\/p>\n

Continue reading “parasites or food resources : which one controls wild fish populations?”<\/span><\/a><\/p>\n","protected":false},"author":1001709,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"","_seopress_titles_title":"","_seopress_titles_desc":"","_seopress_robots_index":"","footnotes":""},"categories":[1],"tags":[],"class_list":{"0":"post-371","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-uncategorized"},"_links":{"self":[{"href":"https:\/\/wp.unil.ch\/lakes\/wp-json\/wp\/v2\/posts\/371","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.unil.ch\/lakes\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wp.unil.ch\/lakes\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/lakes\/wp-json\/wp\/v2\/users\/1001709"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.unil.ch\/lakes\/wp-json\/wp\/v2\/comments?post=371"}],"version-history":[{"count":0,"href":"https:\/\/wp.unil.ch\/lakes\/wp-json\/wp\/v2\/posts\/371\/revisions"}],"wp:attachment":[{"href":"https:\/\/wp.unil.ch\/lakes\/wp-json\/wp\/v2\/media?parent=371"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.unil.ch\/lakes\/wp-json\/wp\/v2\/categories?post=371"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.unil.ch\/lakes\/wp-json\/wp\/v2\/tags?post=371"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}