Journal articles: 'Otolith chronology'

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Carvalho, Carla, Fabiana Oliveira, Kita Macario, Tania Lima, Ingrid Chanca, Eduardo Q. Alves, Thayse Bertucci, and Orangel Aguilera. "Otolith-Based Chronology of Brazilian Shellmounds." Radiocarbon 61, no. 2 (January 25, 2019): 415–33. http://dx.doi.org/10.1017/rdc.2018.135.

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ABSTRACTThe radiocarbon (14C) chronology of hunter-fisher-gatherers’ archaeological settlements along the Brazilian coast is usually based on mollusk shells, charcoal from hearths, and eventually human bones. However, fish otoliths are found in several archaeological contexts and may represent a reliable option as a chronological record. In this work, we compare the 14C dates of whitemouth croakers (Micropogonias furnieri) otoliths with dates obtained from other materials (shell and charcoal), collected from shellmounds on the coast of Rio de Janeiro, with the aim of improving the accuracy in the 14C dating of Brazilian shellmounds, strengthening the comprehension of the native populations’ occupational trends and the coeval palaeoceanographic context. Based on x-ray diffraction results for archaeological otoliths, their geochemical composition indicates minimal diagenesis effect over time even under burial conditions in the studied sites. The comparison between otolith dates and dates obtained from other proxies revealed similar results but with decreased deviations in otolith dates in all of the studied sites.

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Weber, Peter K., Ian D. Hutcheon, Kevin D. McKeegan, and B. Lynn Ingram. "Otolith sulfur isotope method to reconstruct salmon (Oncorhynchus tshawytscha) life history." Canadian Journal of Fisheries and Aquatic Sciences 59, no. 4 (April 1, 2002): 587–91. http://dx.doi.org/10.1139/f02-038.

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We report a new ion microprobe method to reconstruct aspects of fish life history based on sulfur isotopes (34S/32S, expressed as δ34S). Selected hatchery raised and naturally spawned juvenile chinook salmon (Oncorhynchus tshawytscha) are shown to have a 12.96 ± 0.27 (mean ± 2 standard errors) difference in muscle δ34S values, corresponding to δ34S differences between the hatchery and freshwater diets. Isotopic microanalyses of otoliths demonstrate that this 13 difference is preserved in the otoliths. We interpret the otolith δ34S record to be a chronology of dietary δ34S, with approximately one-week temporal resolution, preserved in these banded calcium carbonate structures. Potential applications of this method include identifying hatchery raised fish and reconstructing nutrition sources, migration, and other aspects of fish life history.

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Izzo, Christopher, Zoë A. Doubleday, Gretchen L. Grammer, Morgan C. F. Disspain, Qifeng Ye, and Bronwyn M. Gillanders. "Seasonally resolved environmental reconstructions using fish otoliths." Canadian Journal of Fisheries and Aquatic Sciences 74, no. 1 (January 2017): 23–31. http://dx.doi.org/10.1139/cjfas-2016-0055.

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Exploiting the chemical and growth properties of otoliths, this study demonstrates how environmental archives with high temporal resolution can be developed. Elemental profiles (Ba:Ca and Sr:Ca) of fish otoliths (ear bones) from the estuarine species Acanthopagrus butcheri (black bream) were related to growth increments on a seasonal time scale. A series of mixed effects models were used to investigate biological, temporal, and environmental factors influencing seasonal otolith elemental profiles. Resultant seasonally resolved chemical chronologies were correlated with environmental data (i.e., salinity) to develop an element–salinity regression function, which when fit to an independently derived chemical chronology showed strong agreement between reconstructed and recorded salinities. Support for the element–salinity regression function through independent verification provided confidence in environmental reconstructions derived from an archaeological otolith. This suggests otoliths can be used to reconstruct past environmental conditions over decadal and centennial time scales. Moreover, the application of mixed effect models to develop chemical chronologies also provides information on drivers of elemental profiles and allows a range of ecological questions to be addressed. This approach may be further adapted and employed across a broader range of taxonomic groups and environments.

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Piner, Kevin R., Owen S. Hamel, Jennifer L. Menkel, John R. Wallace, and Charles E. Hutchinson. "Age validation of canary rockfish (Sebastes pinniger) from off the Oregon coast (USA) using the bomb radiocarbon method." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 5 (May 1, 2005): 1060–66. http://dx.doi.org/10.1139/f05-082.

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The alternating translucent and opaque banding pattern in canary rockfish (Sebastes pinniger) otoliths, aged using a break-and-burn methodology, are annual markings. To validate age assignment, we compared measured radiocarbon levels in canary rockfish otolith cores with a reference chronology developed from known age Pacific halibut (Hippoglossus stenolepis). An average 2- to 3-year phase shift was detected between the canary rockfish and a Pacific halibut reference chronology that was likely the result of differences in the regional oceanography or underageing bias. The assumption of ageing bias consistency was tested with two sampling designs. The first design controled for age-related ageing error, and the second design related birth year to estimated age. No change in the magnitude of ageing bias as a function of age was detected.

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Shervette, Virginia R., Katherine E. Overly, and Jesús M. Rivera Hernández. "Radiocarbon in otoliths of tropical marine fishes: Reference Δ14C chronology for north Caribbean waters." PLOS ONE 16, no. 5 (May 12, 2021): e0251442. http://dx.doi.org/10.1371/journal.pone.0251442.

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Reef fishes support important fisheries throughout the Caribbean, but a combination of factors in the tropics makes otolith microstructure difficult to interpret for age estimation. Therefore, validation of ageing methods, via application of Δ14C is a major research priority. Utilizing known-age otolith material from north Caribbean fishes, we determined that a distinct regional Δ14C chronology exists, differing from coral-based chronologies compiled for ageing validation from a wide-ranging area of the Atlantic and from an otolith-based chronology from the Gulf of Mexico. Our north Caribbean Δ14C chronology established a decline series with narrow prediction intervals that proved successful in ageing validation of three economically important reef fish species. In examining why our north Caribbean Δ14C chronology differed from some of the coral-based Δ14C data reported from the region, we determined differences among study objectives and research design impact Δ14C temporal relationships. This resulted in establishing the first of three important considerations relevant to applying Δ14C chronologies for ageing validation: 1) evaluation of the applicability of original goal/objectives and study design of potential Δ14C reference studies. Next, we determined differences between our Δ14C chronology and those from Florida and the Gulf of Mexico were explained by differences in regional patterns of oceanic upwelling, resulting in the second consideration for future validation work: 2) evaluation of the applicability of Δ14C reference data to the region/location where fish samples were obtained. Lastly, we emphasize the application of our north Caribbean Δ14C chronology should be limited to ageing validation studies of fishes from this region known to inhabit shallow water coral habitat as juveniles. Thus, we note the final consideration to strengthen findings of future age validation studies: 3) use of Δ14C analysis for age validation should be limited to species whose juvenile habitat is known to reflect the regional Δ14C reference chronology.

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Andrews, Allen H., Edward E. DeMartini, Jeff A. Eble, Brett M. Taylor, Dong Chun Lou, and Robert L. Humphreys. "Age and growth of bluespine unicornfish (Naso unicornis): a half-century life-span for a keystone browser, with a novel approach to bomb radiocarbon dating in the Hawaiian Islands." Canadian Journal of Fisheries and Aquatic Sciences 73, no. 10 (October 2016): 1575–86. http://dx.doi.org/10.1139/cjfas-2016-0019.

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Bluespine unicornfish (Naso unicornis) from Hawaii were aged to >50 years using cross-sectioned sagittal otoliths. Fish length was a poor indicator of age because of rapid and variable early growth, exemplified by fish aged to be 4 years near maximum length. Growth was deterministic with adult ages decoupled from body length. Otolith mass and thickness were evaluated as proxies for age and both were encouraging; thickness explained more variance but mass was easier to measure. An age estimation protocol was validated through ontogeny using bomb radiocarbon (14C) dating. Use of the postbomb 14C decline period from a regional reference chronology enabled age validation of young fish — a novel approach for the Pacific Ocean. A probabilistic procedure for assigning bomb 14C dates (CALIBomb) was used for the first time to determine fish birth years. The age-reading protocol was generally validated, and it was possible to describe length-at-age despite difficulties in counting otolith annuli beyond 30–40 years. Growth curves differed between the sexes, and a four-parameter generalized von Bertalanffy growth function provided the best fit.

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Kaiser, Michel J. "Otolith microchemistry helps to unlock the chronology of age determination." Journal of Fish Biology 97, no. 2 (August 2020): 323. http://dx.doi.org/10.1111/jfb.14470.

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Zimmerman, Christian E. "Relationship of otolith strontium-to-calcium ratios and salinity: experimental validation for juvenile salmonids." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 1 (January 1, 2005): 88–97. http://dx.doi.org/10.1139/f04-182.

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Analysis of otolith strontium (Sr) or strontium-to-calcium (Sr:Ca) ratios provides a powerful tool to reconstruct the chronology of migration among salinity environments for diadromous salmonids. Although use of this method has been validated by examination of known individuals and translocation experiments, it has never been validated under controlled experimental conditions. In this study, incorporation of otolith Sr was tested across a range of salinities and resulting levels of ambient Sr and Ca concentrations in juvenile chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), sockeye salmon (Oncorhynchus nerka), rainbow trout (Onco rhynchus mykiss), and Arctic char (Salvelinus alpinus). Experimental water was mixed, using stream water and seawater as end members, to create experimental salinities of 0.1, 6.3, 12.7, 18.6, 25.5, and 33.0 psu. Otolith Sr and Sr:Ca ratios were significantly related to salinity for all species (r2 range: 0.800.91) but provide only enough predictive resolution to discriminate among fresh water, brackish water, and saltwater residency. These results validate the use of otolith Sr:Ca ratios to broadly discriminate salinity histories encountered by salmonids but highlight the need for further research concerning the influence of osmoregulation and physiological changes associated with smolting on otolith microchemistry.

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Campana, Steven E., John M. Casselman, and Cynthia M. Jones. "Bomb radiocarbon chronologies in the Arctic, with implications for the age validation of lake trout (Salvelinus namaycush) and other Arctic species." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 4 (April 1, 2008): 733–43. http://dx.doi.org/10.1139/f08-012.

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Radiocarbon generated by atmospheric testing of nuclear weapons (bomb radiocarbon) produced a strong signal with an abrupt onset in the 1950s, which serves as a dated marker for tracing oceanic circulation and confirming age in animals forming growth bands. Here, we report the first prebomb and postbomb radiocarbon chronologies for marine and freshwater environments in the Canadian Arctic, extend the radiocarbon chronology for the northwest Atlantic Ocean, and use the onset of the bomb signal to validate our age interpretations of lake trout (Salvelinus namaycush) in Arctic lakes. Both surface and deepwater Arctic chronologies became detectable on or around 1958, similar to the year of onset elsewhere in the world. In contrast, the freshwater Arctic chronology increased sharply in 1957, with a peak value sixfold higher than the adjacent marine environment. The radiocarbon content of the adult otolith core validated our age interpretation criteria for Arctic lake trout to an age of at least 50 years. Otolith growth in such slow-growing fish was so low as to be unresolvable under conventional examination with a dissecting microscope. With these new radiocarbon reference chronologies, age validation of a large number of Arctic organisms should now be possible.

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Folkvord, Arild, Geir Gundersen, Jon Albretsen, Lars Asplin, Stein Kaartvedt, and Jarl Giske. "Impact of hatch date on early life growth and survival of Mueller’s pearlside (Maurolicus muelleri) larvae and life-history consequences." Canadian Journal of Fisheries and Aquatic Sciences 73, no. 2 (February 2016): 163–76. http://dx.doi.org/10.1139/cjfas-2015-0040.

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Growth and survival of Maurolicus muelleri larvae in Herdlefjorden, Norway, were investigated by daily otolith increment analysis. While high egg densities were generally observed throughout the spawning season, three cohorts each with a narrow window of hatching dates were identified. The first of these cohorts was characterized by low growth and poor morphometric condition and disappeared from the fjord during autumn. High-resolution drift modeling indicated that Herdlefjorden had a net export of larvae and negligible import in the period cohort 1 disappeared. Yet, the advective loss rate of larvae was not considered high enough to explain the near complete disappearance of the first cohort. An otolith-based growth chronology indicated that growth conditions in Herdlefjorden improved noticeably around mid-September and remained favorable the following month. The analysis of daily otolith increments could thus be used to document within-season variability in larval growth and survival. The low and variable survival due to short-term fluctuations in environmental conditions indicate that multiple batch spawning is an adequately evolved life-history strategy for marine planktivorous fish such as M. muelleri.

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Treble, Margaret A., Steven E. Campana, Rick J. Wastle, Cynthia M. Jones, and Jesper Boje. "Growth analysis and age validation of a deepwater Arctic fish, the Greenland halibut (Reinhardtius hippoglossoides)." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 6 (June 2008): 1047–59. http://dx.doi.org/10.1139/f08-030.

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The accuracy of age interpretations on a deep-sea, Arctic fish species, the Greenland halibut ( Reinhardtius hippoglossoides ) was tested using several age validation methods. Consistent annual growth increments were either not formed or not visible in either whole or sectioned otoliths from three fish marked with oxytetracyline and recaptured after 2–4 years at liberty. Bomb radiocarbon assays based on a local reference chronology indicated that both whole and sectioned otoliths underestimated age by 1–15 years, with an average of 6 years. Growth rates estimated using the tag recapture model GROTAG were consistent with growth rates based on the radiocarbon assays and were less than half that of previously reported growth rates. The failure of otolith sections to provide an accurate age is unusual, but may be symptomatic of very slow-growing species with unusually shaped otoliths. Greenland halibut living in the deep-sea, Arctic environment are slower growing and longer lived than previously suspected, suggesting that the age-structured basis for current fisheries management warrants careful examination. Our results highlight the importance of using rigorous tests of ageing accuracy for exploited species and confirm that such age validation methods can be applied successfully in challenging environments such as the deep sea or the Arctic.

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Kastelle, Craig, Thomas Helser, Todd TenBrink, Charles Hutchinson, Betty Goetz, Chris Gburski, and Irina Benson. "Age validation of four rockfishes (genera Sebastes and Sebastolobus) with bomb-produced radiocarbon." Marine and Freshwater Research 71, no. 10 (2020): 1355. http://dx.doi.org/10.1071/mf19280.

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In rockfish (Family Scorpaenidae), age determination is difficult and the annual nature of otolith growth zones must be validated independently. We applied routine age determination to four species of Gulf of Alaska rockfish: two shallower-water species, namely harlequin rockfish (Sebastes variegatus) and redstripe rockfish (Sebastes proriger), and two deep-water species, namely shortspine thornyhead (Sebastolobus alascanus) and shortraker rockfish (Sebastes borealis). The estimated ages (counts of presumed annual growth zones in the otoliths) were then evaluated with bomb-produced radiocarbon (14C) and Bayesian modelling with Markov chain Monte Carlo simulations. This study successfully demonstrated the level of accuracy in estimated ages of redstripe rockfish (a 35% probability of underageing, and ~5% probability of overageing) and harlequin rockfish (a 100% probability that they were underaged by ~3 or 4 years). Measured Δ14C in shortspine thornyhead and shortraker rockfish otoliths was lower and increased later than expected. Hence, incorrect age determination could not be evaluated. This is likely caused by dissimilar environmental and biological availability of 14C between these two species and the Pacific halibut (Hippoglossus stenolepis) reference chronology, or underageing of these two species.

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Sherwood, John E., Jim M. Bowler, Stephen P. Carey, John Hellstrom, Ian J. McNiven, Colin V. Murray-Wallace, John R. Prescott, et al. "The Moyjil site, south-west Victoria, Australia: chronology." Proceedings of the Royal Society of Victoria 130, no. 2 (2018): 32. http://dx.doi.org/10.1071/rs18005.

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An unusual shell deposit at Moyjil (Point Ritchie), Warrnambool, in western Victoria, has previously been dated at 67±10 ka and has features suggesting a human origin. If human, the site would be one of Australia’s oldest, justifying a redetermination of age using amino acid racemisation (AAR) dating of Lunella undulata (syn. Turbo undulatus) opercula (the dominant shellfish present) and optically stimulated luminescence (OSL) of the host calcarenite. AAR dating of the shell bed and four Last Interglacial (LIG) beach deposits at Moyjil and Goose Lagoon, 30 km to the west, confirmed a LIG age. OSL analysis of the host sand revealed a complex mixing history, with a significant fraction (47%) of grains giving an early LIG age (120–125 ka) using a three-component mixing model. Shell deposition following the LIG sea-level maximum at 120–125 ka is consistent with stratigraphic evidence. A sand layer immediately below the shell deposit gave an age of ~240 ka (i.e. MIS 7) and appears to have been a source of older sand incorporated into the shell deposit. Younger ages (~60–80 ka) are due to bioturbation before calcrete finally sealed the deposit. Uranium/thorium methods were not applicable to L. undulata opercula or an otolith of the fish Argyrosomus hololepidotus because they failed to act as closed systems. A U–Th age of 103 ka for a calcrete sheet within the 240 ka sand indicates a later period of carbonate deposition. Calcium carbonate dripstone from a LIG wave-cut notch gave a U–Th age of 11–14 ka suggesting sediment cover created a cave-like environment at the notch at this time. The three dating techniques have collectively built a chronology spanning the periods before and after deposition of the shell bed, which occurred just after the LIG sea-level maximum (120–125 ka).

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Vieira, Ana Rita, Sandra Dores, Manuela Azevedo, and Susanne E. Tanner. "Otolith increment width-based chronologies disclose temperature and density-dependent effects on demersal fish growth." ICES Journal of Marine Science 77, no. 2 (December 17, 2019): 633–44. http://dx.doi.org/10.1093/icesjms/fsz243.

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Abstract Climate change and fishing are drastically impacting marine ecosystems. Comprehending the biological consequences of these effects on commercially exploited fish is especially challenging. Here, we developed a 43-year otolith increment width-based growth chronology for one of the most important commercially exploited fish species in the Northeast Atlantic (European hake, Merluccius merluccius). Increasingly complex linear mixed-effects models were used to partition growth variation into intrinsic (age, sex, and age-at-capture) and extrinsic (environmental and biotic variables) factors, allowing age interaction with extrinsic variables to assess age-dependent responses in growth. Our results provided strong evidence that European hake growth is impacted by ocean temperature, namely sea surface temperature and temperature at depth, and species abundance (recruitment), with different responses depending on fish age. We found evidence that increasing ocean temperature could be highly detrimental for species growth especially during the first years of life. We provided insights into the effects of environmental and biotic factors on species growth variation. Such information is key to recognize the sensitivity of European hake growth to climate change, which may contribute to sustainable management policies for this valuable resource.

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Milheira, Rafael G., Kita D. Macario, Ingrid S. Chanca, and Eduardo Q. Alves. "Archaeological Earthen Mound Complex in Patos Lagoon, Southern Brazil: Chronological Model and Freshwater Influence." Radiocarbon 59, no. 1 (February 2017): 195–214. http://dx.doi.org/10.1017/rdc.2017.5.

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AbstractIn the present work, we assess the chronology of archaeological sites known as earthen mounds, commonly found at the Pampas biome, among the lowlands of Brazil, Uruguay, and Argentina. We focused on the Pontal da Barra settlement, which is a testimony of the long-term occupation of indigenous groups in the swamp and wet environment of Patos Lagoon, southern Brazil. A Bayesian chronological model based on the radiocarbon (14C) dating of 17 samples of fish otolith, 5 charcoal fragments, and 2 bones (human and dog) allowed determination of the beginning of the occupation as well as the occupational synchronism of the different mounds. The nature of the samples allows us to study the local 14C reservoir effect through the comparison between the group of marine and terrestrial samples, deriving a reservoir offset value of 63±53 14C yr for this particular area, indicating a strong freshwater influence in the lagoon system. We estimate the start of human intervention in the landscapes of southern Patos Lagoon to be around 2200 cal BP, with the most intense activity between 1800 and 1200 cal BP.

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Wischniowski, Stephen G., Craig R. Kastelle, Timothy Loher, and Thomas E. Helser. "Incorporation of bomb-produced14C into fish otoliths. An example of basin-specific rates from the North Pacific Ocean." Canadian Journal of Fisheries and Aquatic Sciences 72, no. 6 (June 2015): 879–92. http://dx.doi.org/10.1139/cjfas-2014-0225.

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Sagittal otoliths from juvenile Pacific halibut (Hippoglossus stenolepis) of known age were used to create a bomb-produced radiocarbon reference chronology for the eastern Bering Sea (EBS) by fitting a coupled-function model to Δ14C values from each specimen’s birth year. The newly created EBS reference chronology was then compared with a reference chronology previously created for Pacific halibut from the Gulf of Alaska (GOA). Adult Pacific halibut age-validation samples from the EBS were also analyzed for14C and modeled to validate age-estimation accuracy. A Bayesian model was developed and Markov chain Monte Carlo simulation was used to estimate model parameters and adult Pacific halibut ageing bias. Differences in reference chronologies between ocean basins were reflected in a large deviance information criterion (ΔDIC) between models, supporting the hypothesis that two separate coupled-function models were required to adequately describe the data, one each for the EBS and GOA. We determined that regionally specific GOA and EBS oceanography plays a considerable role in the Δ14C values and must be taken into consideration when selecting a reference chronology for bomb-produced14C age-validation studies. The age-validation samples indicated that the current ageing methodology used in Pacific halibut assessments is accurate and has provided accurate age assignments for Pacific halibut in the EBS.

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Piner, K. R., and S. G. Wischniowski. "Pacific halibut chronology of bomb radiocarbon in otoliths from 1944 to 1981 and a validation of ageing methods." Journal of Fish Biology 64, no. 4 (April 2004): 1060–71. http://dx.doi.org/10.1111/j.1095-8649.2004.0371.x.

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Cerna, Francisco, Guillermo Moyano, Christian Valero, Lizandro Muñoz, Guido Plaza, and Steven E. Campana. "Bomb Radiocarbon, Otolith Daily Increments and Length Modes Validate Age Interpretations of Chilean Jack Mackerel (Trachurus murphyi)." Frontiers in Marine Science 9 (July 20, 2022). http://dx.doi.org/10.3389/fmars.2022.906583.

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Ages of Chilean jack mackerel (Trachurus murphyi) in the southern Pacific Ocean were validated using three methods: 1) daily microincrement readings in sagittal otoliths of young-of-the year (YOY) fish to validate the first annulus; 2) modal progression of strong year-classes (PSYC) to validate the first, second and third annuli, and 3) bomb radiocarbon analysis of otolith cores to validate the absolute age in older fish >38 cm fork length (FL). A Laird-Gompertz (LG) model was fitted to fork length (cm) at age (days) relationship in fish ranging from 3.4 to 25.0 cm FL and from 56 to 550 days in age. The LG model estimated a mean FL of 22 cm at the end of the first year of life, which was large compared with the mean FL estimated through conventional ageing in whole otoliths. The comparison between daily age with annual growth bands from whole otoliths, showed a false increment formed at 185 ± 34 days and a second translucent increment formed at 352 ± 79 days, corresponding to the first annulus for fish with the mean FL of 21.4 ± 1.8 cm. The PSYC coinciding with the recruits of 2008 (age 0), was tracked through three subsequent years with high accuracy, attaining 23, 27 and 30 cm FL in 2009, 2010 and 2011, respectively. These modes identified as age 1, age 2 and age 3 in the PSYC, matched to the mean length of fish with 2, 4 and 5 translucent increments in sagittal otoliths. Results from bomb radiocarbon analysis confirmed that most of the ages were correct, because the Δ14C content of adult otolith core matched the reference chronology. The absolute mean ages for the assayed otoliths, based on the comparison with the reference chronology, ranged from 7 to 13 years for sizes between 39 and 60 cm FL. The age validation for T. murphy as addressed in the current study provided crucial information for enhancing stock assessment output of this important transboundary commercial species.

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Neves, João, Eva Giacomello, Gui M. Menezes, Jorge Fontes, and Susanne E. Tanner. "Temperature-Driven Growth Variation in a Deep-Sea Fish: The Case of Pagellus bogaraveo (Brünnich, 1768) in the Azores Archipelago." Frontiers in Marine Science 8 (August 25, 2021). http://dx.doi.org/10.3389/fmars.2021.703820.

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The deep ocean ecosystem hosts high biodiversity and plays a critical role for humans through the ecosystem services it provides, such as fisheries and climate regulation. However, high longevity, late reproduction, and low fecundity of many organisms living in the deep ocean make them particularly vulnerable to fishing and climate change. A better understanding of how exploitation and changing environmental conditions affect life-history parameters (e.g., growth) of commercially important fish species is crucial for their long-term sustainable management. To this end, we used otolith increment widths and a mixed-effects modeling approach to develop a 42-year growth chronology (1975–2016) of the commercially important deep-sea fish species blackspot seabream (Pagellus bogaraveo) among the three island groups of the Azores archipelago (Northeast Atlantic). Growth was related to intrinsic (age and age-at-capture) and extrinsic factors (capture location, temperature-at-depth, North Atlantic Oscillation (NAO), Eastern Atlantic Pattern (EAP), and proxy for exploitation (landings)). Over the four decades analyzed, annual growth patterns varied among the three island groups. Overall, temperature-at-depth was the best predictor of growth, with warmer water associated with slower growth, likely reflecting physiological conditions and food availability. Average population growth response to temperature was separated into among-individual variation and within-individual variation. The significant among-individual growth response to temperature was likely related to different individual-specific past experiences. Our results suggested that rising ocean temperature may have important repercussions on growth, and consequently on blackspot seabream fishery production. Identifying drivers of blackspot seabream growth variation can improve our understanding of past and present condition of the populations toward the sustainable management of the fishery.

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Samor Lopes, Mariana, Elise Dufour, Elisamara Sabadini-Santos, Maria Dulce Gaspar, Kita Macario, Bruna da Silva Mota Neto, Olivier Tombret, et al. "STABLE ISOTOPIC ANALYSIS AND RADIOCARBON DATING OF MICROPOGONIAS FURNIERI OTOLITHS (SCIAENIDAE) FROM SOUTHEASTERN BRAZILIAN COAST: SEASONAL PALAEOENVIRONMENTAL INSIGHT." Radiocarbon, September 12, 2022, 1–29. http://dx.doi.org/10.1017/rdc.2022.57.

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ABSTRACT Isotopic analysis of Micropogonias furnieri otoliths were used to get insight into palaeoceanographic conditions in the Guanabara Bay and Saquarema Lagoon, Rio de Janeiro state (RJ), located on the southeastern coast of Brazil, under upwelling influence of the Cabo Frio system. Archaeological otoliths come from two Holocene shellmounds (or sambaquis): Galeão and Beirada. For the first time, radiocarbon analysis using high accuracy techniques were performed at Galeão. Age range was determined to be between 5820 and 4980 cal BP, which extends the chronology of human settlement in the Guanabara Bay. Micro-samples of the otoliths were collected sequentially from the core to the edge, to provide continuous δ18O and δ13C isotopic profiles over the lifetime of the individual fish. Derived-δ18Ooto palaeotemperature estimates vary according to seasonality, resulting in a palaeoceanographic variation between 8 to 31°C for Guanabara Bay and 8 and 28°C for the Saquarema Lagoon. Our data indicate that whitemouth croakers were captured during the Middle Holocene from the Guanabara Bay and Saguarema Lagoon and resided in cooler temperatures compared to temperatures of current conditions.

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Journal articles on the topic 'Otolith chronology'

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