{"id":468417,"date":"2026-02-11T17:03:08","date_gmt":"2026-02-11T17:03:08","guid":{"rendered":"https:\/\/www.newsbeep.com\/ca\/468417\/"},"modified":"2026-02-11T17:03:08","modified_gmt":"2026-02-11T17:03:08","slug":"ancient-fish-ear-stones-reveal-modern-caribbean-reefs-have-lost-their-dietary-complexity","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ca\/468417\/","title":{"rendered":"Ancient fish ear stones reveal modern Caribbean reefs have lost their dietary complexity"},"content":{"rendered":"

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\"A<\/p>\n

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image:\u00a0<\/p>\n

A secretary blenny\u00a0(Acanthemble\u00a0maria)\u00a0from Panama.<\/p>\n

view more\u00a0<\/a><\/p>\n

Credit: Tim Treuer<\/p>\n

Coral reefs are undoubtedly in crisis. Scientists have documented\u00a0concerning coral bleaching events,\u00a0dramatic declines in coral cover,\u00a0fish\u00a0and\u00a0shark populations\u00a0across the Caribbean over recent decades. But a critical question has\u00a0remained\u00a0unanswered: has the way energy flows through reef ecosystems also changed? A new study led by scientists at the Smithsonian Tropical Research Institute (STRI) and published in\u00a0Nature\u00a0reveals that it\u00a0has,\u00a0profoundly. Food chains on modern Caribbean reefs are 60-70% shorter than they were 7,000 years ago, and individual fish have lost the dietary\u00a0specialisation\u00a0that once sustained a complex web of energy pathways.\u00a0<\/p>\n

The\u00a0discovery\u00a0was\u00a0made\u00a0possible\u00a0by\u00a0an\u00a0unlikely\u00a0combination:\u00a0thousands\u00a0of\u00a0tiny\u00a0fish\u00a0ear\u00a0stones\u00a0(otoliths)\u00a0preserved\u00a0in\u00a0ancient\u00a0reef\u00a0sediments, and a\u00a0high-sensitivity\u00a0technique\u00a0for\u00a0measuring\u00a0nitrogen\u00a0isotopes\u00a0locked\u00a0inside\u00a0them.\u00a0The\u00a0nitrogen\u00a0isotope\u00a0ratio in\u00a0an\u00a0otolith\u00a0reflects\u00a0what\u00a0a\u00a0fish\u00a0ate\u00a0during\u00a0its\u00a0lifetime,\u00a0providing\u00a0a\u00a0chemical\u00a0record\u00a0of\u00a0its\u00a0place in\u00a0the\u00a0food\u00a0chain.\u00a0By\u00a0comparing\u00a0otoliths\u00a0and\u00a0corals\u00a0from\u00a07,000-year-old\u00a0fossil\u00a0reefs\u00a0with\u00a0those\u00a0from\u00a0nearby\u00a0modern\u00a0reefs\u00a0in\u00a0Panama\u00a0and\u00a0the\u00a0Dominican\u00a0Republic,\u00a0the\u00a0research\u00a0team\u00a0reconstructed\u00a0the\u00a0trophic\u00a0structure\u00a0of\u00a0Caribbean\u00a0reef\u00a0fish\u00a0communities\u00a0before\u00a0and after\u00a0centuries\u00a0of\u00a0human\u00a0impact.\u00a0<\/p>\n

The\u00a0results\u00a0paint\u00a0a\u00a0stark\u00a0picture.\u00a0Relatively\u00a0higher-trophic-level\u00a0fishes\u00a0such\u00a0as\u00a0grunts\u00a0and\u00a0cardinalfishes\u00a0now\u00a0feed\u00a0at\u00a0lower\u00a0positions in\u00a0the\u00a0food\u00a0chain,\u00a0whilst\u00a0low-level\u00a0fishes\u00a0like\u00a0gobies\u00a0have\u00a0shifted\u00a0surprisingly\u00a0up\u00a0the\u00a0food\u00a0chain.\u00a0The\u00a0net\u00a0effect:\u00a0the\u00a0distance\u00a0between\u00a0them\u00a0has\u00a0compressed\u00a0by\u00a0around\u00a060% in\u00a0both\u00a0regions. At\u00a0the\u00a0same\u00a0time,\u00a0the\u00a0dietary\u00a0variation\u00a0within\u00a0fish\u00a0families\u00a0has\u00a0narrowed\u00a0by\u00a020\u201370%,\u00a0meaning\u00a0individual\u00a0fish\u00a0that\u00a0once\u00a0specialised\u00a0on\u00a0distinct\u00a0prey\u00a0now\u00a0eat\u00a0much\u00a0the\u00a0same\u00a0things\u00a0as\u00a0their\u00a0neighbours.\u00a0<\/p>\n

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“What\u00a0struck\u00a0us\u00a0is\u00a0how\u00a0consistent\u00a0the\u00a0pattern\u00a0is,”\u00a0said\u00a0Jessica\u00a0Lueders-Dumont, a postdoctoral marine\u00a0biogeochemist\u00a0who\u00a0led\u00a0the\u00a0study. “In\u00a0every\u00a0fish\u00a0family\u00a0we\u00a0examined, in\u00a0both\u00a0Panama\u00a0and\u00a0the\u00a0Dominican\u00a0Republic,\u00a0the\u00a0dietary\u00a0diversity\u00a0has\u00a0contracted.\u00a0These\u00a0reefs\u00a0have\u00a0lost\u00a0an\u00a0entire\u00a0dimension\u00a0of\u00a0ecological\u00a0complexity\u00a0that\u00a0we\u00a0didn’t\u00a0even\u00a0know\u00a0was\u00a0missing.”\u00a0<\/p>\n

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This\u00a0study\u00a0builds\u00a0on\u00a0over\u00a0a\u00a0decade\u00a0of\u00a0fieldwork\u00a0at STRI in\u00a0Panama.\u00a0Beginning\u00a0in\u00a0the\u00a0early\u00a02010s, a\u00a0team\u00a0led\u00a0by\u00a0STRI\u00a0scientist\u00a0Aaron\u00a0O’Dea\u00a0excavated\u00a0tonnes\u00a0of\u00a0sediment\u00a0from\u00a0exceptionally\u00a0well-preserved\u00a0fossil\u00a0reefs\u00a0in Bocas del Toro,\u00a0Panama, and\u00a0the\u00a0Enriquillo\u00a0Basin\u00a0in\u00a0the\u00a0Dominican\u00a0Republic.\u00a0These\u00a0beautiful\u00a07,000-year-old,\u00a0mid-Holocene\u00a0reef\u00a0deposits\u00a0in\u00a0the\u00a0Caribbean\u00a0preserve\u00a0conditions\u00a0before\u00a0human\u00a0impact: a\u00a0remarkable\u00a0archive\u00a0that\u00a0has\u00a0already\u00a0yielded\u00a0insights\u00a0into\u00a0coral\u00a0shifts\u00a0and\u00a0the\u00a0ecological\u00a0consequences\u00a0of\u00a0predator\u00a0loss.\u00a0<\/p>\n

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“Otoliths\u00a0are\u00a0incredible\u00a0structures, and\u00a0when\u00a0we\u00a0first\u00a0started\u00a0finding\u00a0them\u00a0in\u00a0our\u00a0fossil\u00a0reef\u00a0samples, I\u00a0realised\u00a0we\u00a0had\u00a0an\u00a0opportunity\u00a0to\u00a0reconstruct\u00a0not\u00a0just\u00a0what\u00a0corals\u00a0were\u00a0like\u00a0before\u00a0humans,\u00a0but\u00a0also\u00a0the\u00a0fishes\u00a0that\u00a0live\u00a0on\u00a0reefs”\u00a0said\u00a0O’Dea.\u00a0<\/p>\n

The\u00a0painstaking\u00a0work\u00a0of\u00a0sorting,\u00a0identifying\u00a0and\u00a0cataloguing\u00a0thousands\u00a0of\u00a0otoliths\u00a0from\u00a0bulk\u00a0reef\u00a0sediment\u00a0was\u00a0carried\u00a0out\u00a0largely\u00a0by\u00a0STRI\u00a0researcher\u00a0Br\u00edgida de Gracia, a\u00a0Ng\u00e4be\u00a0palaeontologist, and\u00a0Chien-Hsiang\u00a0Lin\u00a0of\u00a0Academia\u00a0Sinica\u00a0in\u00a0Taiwan.\u00a0Their\u00a0development\u00a0of\u00a0otolith\u00a0reference\u00a0collections\u00a0and\u00a0taxonomic\u00a0expertise\u00a0laid\u00a0the\u00a0groundwork\u00a0for\u00a0the\u00a0study.\u00a0<\/p>\n

“Picking\u00a0otoliths\u00a0from\u00a0sediment,\u00a0grain\u00a0by\u00a0grain,\u00a0is\u00a0challenging\u00a0but\u00a0you\u00a0develop\u00a0an\u00a0intimate\u00a0relationship\u00a0with\u00a0these\u00a0ancient\u00a0reefs,”\u00a0said\u00a0de Gracia. “Every\u00a0otolith\u00a0tells\u00a0the\u00a0story\u00a0of\u00a0a\u00a0fish\u00a0that\u00a0lived\u00a0thousands\u00a0of\u00a0years\u00a0ago.\u00a0To\u00a0see\u00a0those\u00a0stories\u00a0come\u00a0alive\u00a0through\u00a0isotope\u00a0chemistry\u00a0is\u00a0incredibly\u00a0rewarding.”\u00a0<\/p>\n

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The\u00a0isotopic\u00a0technique\u00a0at\u00a0the\u00a0heart\u00a0of\u00a0the\u00a0study\u00a0was\u00a0developed\u00a0by\u00a0Lueders-Dumont\u00a0\u00a0\u00a0in\u00a0co-author\u00a0Daniel\u00a0Sigman\u2019s\u00a0laboratory\u00a0at Princeton\u00a0University.\u00a0The\u00a0method\u00a0extracts\u00a0and\u00a0measures\u00a0nitrogen\u00a0locked\u00a0within\u00a0the\u00a0mineral\u00a0structure\u00a0of\u00a0the\u00a0otoliths:\u00a0organic\u00a0matter\u00a0that\u00a0has\u00a0been\u00a0sealed\u00a0away\u00a0for\u00a0millennia,\u00a0protected\u00a0from\u00a0degradation\u00a0by\u00a0the\u00a0surrounding\u00a0calcium\u00a0carbonate.\u00a0<\/p>\n

The\u00a0team\u00a0focused\u00a0on\u00a0four\u00a0fish\u00a0families\u00a0that\u00a0represent\u00a0different\u00a0ecological\u00a0roles\u00a0on\u00a0the\u00a0reef:\u00a0gobies\u00a0(small\u00a0bottom-dwellers),\u00a0silversides\u00a0(pelagic\u00a0schooling\u00a0fish),\u00a0cardinalfishes\u00a0(nocturnal\u00a0predators)\u00a0and\u00a0grunts\u00a0(larger\u00a0omnivores\u00a0that\u00a0roam\u00a0between\u00a0reef\u00a0and\u00a0mangrove\u00a0habitats).\u00a0Crucially,\u00a0most\u00a0of\u00a0these\u00a0species\u00a0are\u00a0not\u00a0targeted\u00a0by\u00a0fisheries,\u00a0meaning\u00a0the\u00a0changes\u00a0reflect\u00a0broad\u00a0ecosystem\u00a0shifts\u00a0rather\u00a0than\u00a0direct\u00a0harvesting\u00a0effects.\u00a0<\/p>\n

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The\u00a0findings\u00a0carry\u00a0a\u00a0sobering\u00a0message\u00a0for\u00a0reef\u00a0conservation.\u00a0When\u00a0individual\u00a0fish\u00a0within\u00a0a\u00a0population\u00a0all\u00a0rely\u00a0on\u00a0the\u00a0same\u00a0pool\u00a0of\u00a0resources\u00a0(rather\u00a0than\u00a0each\u00a0specialising\u00a0on\u00a0different\u00a0prey), a\u00a0single\u00a0disruption\u00a0to\u00a0food\u00a0supply\u00a0can\u00a0affect\u00a0the\u00a0entire\u00a0population\u00a0simultaneously.\u00a0The\u00a0prehistoric\u00a0reefs,\u00a0by\u00a0contrast,\u00a0supported\u00a0a\u00a0diversity\u00a0of\u00a0energy\u00a0pathways\u00a0that\u00a0would\u00a0have\u00a0buffered\u00a0the\u00a0system\u00a0against\u00a0shocks.\u00a0The\u00a0loss\u00a0of\u00a0this\u00a0trophic\u00a0complexity\u00a0represents\u00a0a\u00a0hidden\u00a0vulnerability:\u00a0one\u00a0that\u00a0is\u00a0invisible\u00a0to\u00a0standard\u00a0reef\u00a0monitoring\u00a0but\u00a0may\u00a0increase\u00a0the\u00a0risk\u00a0of\u00a0cascading\u00a0ecosystem\u00a0collapse.\u00a0<\/p>\n

“We\u00a0already\u00a0knew\u00a0that\u00a0modern\u00a0Caribbean\u00a0reefs\u00a0are home\u00a0to\u00a0fewer\u00a0corals\u00a0and\u00a0fewer\u00a0sharks,”\u00a0said\u00a0O’Dea. “Now\u00a0we\u00a0can\u00a0see\u00a0that\u00a0the\u00a0fish\u00a0that\u00a0remain\u00a0are\u00a0feeding\u00a0and\u00a0behaving\u00a0differently\u00a0too.\u00a0It\u00a0strengthens\u00a0the\u00a0case\u00a0that\u00a0modern\u00a0Caribbean\u00a0reefs\u00a0are\u00a0not\u00a0simply\u00a0diminished\u00a0versions\u00a0of\u00a0what\u00a0came\u00a0before;\u00a0they\u00a0are\u00a0potentially\u00a0functioning\u00a0in\u00a0different\u00a0ways”\u00a0<\/p>\n

The\u00a0study\u00a0also\u00a0provides\u00a0a new\u00a0tool\u00a0for\u00a0reef\u00a0assessment. “We\u00a0now\u00a0have\u00a0a\u00a0way\u00a0to\u00a0explore\u00a0how\u00a0entire\u00a0systems\u00a0function,”\u00a0said\u00a0Lueders-Dumont. “These\u00a0tiny\u00a0ear\u00a0stones\u00a0are\u00a0opening\u00a0a\u00a0window\u00a0into\u00a0how\u00a0energy\u00a0moves\u00a0through\u00a0reef\u00a0ecosystems\u00a0on\u00a0time\u00a0scales\u00a0previously\u00a0unimaginable\u00a0to\u00a0ecologists”.\u00a0<\/p>\n

About the Smithsonian Tropical Research Institute<\/p>\n

Headquartered in Panama City, Panama, STRI is a unit of the Smithsonian Institution.\u00a0Our\u00a0mission is to understand tropical biodiversity and its importance to human welfare,\u00a0to\u00a0train students to conduct research in the tropics and\u00a0to\u00a0promote conservation by increasing public awareness of the beauty and importance of tropical ecosystems.\u00a0Watch our\u00a0video, and\u00a0visit\u00a0our\u00a0website,\u00a0Facebook,\u00a0X\u00a0and\u00a0Instagram\u00a0for updates.<\/p>\n

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.<\/p>\n","protected":false},"excerpt":{"rendered":"image:\u00a0 A secretary blenny\u00a0(Acanthemble\u00a0maria)\u00a0from Panama. view more\u00a0 Credit: Tim Treuer Coral reefs are undoubtedly in crisis. Scientists have…\n","protected":false},"author":2,"featured_media":468418,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[49,48,66],"class_list":["post-468417","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ca","tag-canada","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/468417","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=468417"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/468417\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/468418"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=468417"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=468417"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=468417"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}