scholarly journals Accuracy of Otolith Oxygen Isotope Records Analyzed by SIMS as an Index of Temperature Exposure of Wild Icelandic Cod (Gadus morhua)

2021 ◽  
Vol 8 ◽  
Author(s):  
Gotje von Leesen ◽  
Hlynur Bardarson ◽  
Sæmundur Ari Halldórsson ◽  
Martin J. Whitehouse ◽  
Steven E. Campana
Keyword(s):  
Oxygen Isotope ◽  
Data Storage ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Estimation Accuracy ◽  
Good Correspondence ◽  
Relative Temperature ◽  
Temperature Reconstructions ◽  
Stable Oxygen ◽  
Temperature Exposure

Global warming is increasing ocean temperatures, forcing marine organisms to respond to a suite of changing environmental conditions. The stable oxygen isotopic composition of otoliths is often used as an index of temperature exposure, but the accuracy of the resulting temperature reconstructions in wild, free-swimming Atlantic cod (Gadus morhua) has never been groundtruthed. Based on temperatures from data storage tags (DST) and corresponding salinity values, the stable oxygen isotope (δ18O) value was predicted for each month of tagging and compared with δ18Ootolith values measured in situ with secondary ion mass spectrometry (SIMS). Paired-sample Wilcoxon tests were applied to compare measured and predicted δ18O values. The difference between measured and predicted mean and maximum δ18Ootolith values was not significant, suggesting a good correspondence between SIMS-measured and DST-predicted δ18Ootolith values. However, SIMS-measured and predicted minimum δ18Ootolith values were significantly different (all samples: p < 0.01, coastal and frontal cod: p < 0.05), resulting in overestimation of maximum temperatures. Our results confirm that otoliths are well-suited as proxies for mean ambient temperature reconstructions. A possible matrix effect and the absence of a reliable aragonite standard for SIMS measurements appeared to cause a small divergence between measured and predicted δ18Ootolith values, which affected the estimation accuracy of absolute temperature. However, relative temperature changes were accurately estimated by SIMS-analyzed δ18Ootolith values.

scholarly journals Stable oxygen isotope reconstruction of temperature exposure of the Icelandic cod (Gadus morhua) stock over the last 100 years

2020 ◽  
Vol 77 (3) ◽  
pp. 942-952 ◽  
Author(s):  
Gotje von Leesen ◽  
Ulysses S Ninnemann ◽  
Steven E Campana
Keyword(s):  
Oxygen Isotope ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Physical Factors ◽  
Mixed Effect ◽  
Stable Oxygen Isotope ◽  
Arctic Regions ◽  
Growth Increments ◽  
Stable Oxygen ◽  
Temperature Exposure

Abstract Increasing water temperatures are predicted around the globe, with high amplitudes of warming in Subarctic and Arctic regions where Atlantic cod (Gadus morhua) populations currently flourish. We reconstructed oxygen isotope and temperature chronologies from Icelandic cod otoliths, one of the largest cod stocks in the world, to determine if cod moved or migrated over the last 100 years to avoid increasing water temperatures. For δ18Ootolith analysis, individual annual growth increments from immature and mature life history stages were micromilled from adult otoliths, which were collected in southern Iceland. Linear mixed-effect models confirmed that stable oxygen isotope time series of immature and mature cod differ significantly between both life stages (p < 0.001). Overall, cod otolith δ18O was significantly correlated with water temperature (sea surface temperature: p < 0.001, temperature at 200 m depth: p < 0.01), indicating that Atlantic cod were exposed to fluctuating water temperatures during the past 100 years and did not move as a response to increasing ocean temperatures. All of the alternate physical factors that were considered for the isotope-based variation in the temperature exposure of Icelandic cod were rejected.

scholarly journals Otolith chemistry and redistributions of Northern cod: evidence of Smith Sound – Bonavista Corridor connectivity

2018 ◽  
Vol 75 (12) ◽  
pp. 2302-2312 ◽  
Author(s):  
Victoria Neville ◽  
George Rose ◽  
Sherrylynn Rowe ◽  
Robyn Jamieson ◽  
Glenn Piercey
Keyword(s):  
Oxygen Isotope ◽  
Gadus Morhua ◽  
Direct Evidence ◽  
Atlantic Cod ◽  
Otolith Chemistry ◽  
Stable Oxygen Isotope ◽  
Metapopulation Structure ◽  
Northern Cod ◽  
Stable Oxygen ◽  
Placentia Bay

Stable oxygen isotope assays of otoliths (δ18Ooto) from migrant Atlantic cod (Gadus morhua Linnaeus, 1758) that overwintered in Smith Sound, Newfoundland, during 1995–2006 differed from those of nonmigrating summer residents and cod from Placentia Bay and Halibut Channel but did not differ from those of cod from the adjacent offshore Bonavista Corridor in summer. All fish sampled were of the 1990 year class (founder of the Smith Sound aggregation) at ages 8–10 years. Hence, overwintering Smith Sound and summering Bonavista Corridor cod likely experienced similar temperatures and salinities in each year of life, representing different migration stages of an intermixed group. Moreover, predictions of δ18Ooto from near-bottom ocean temperatures and salinities differed between inshore and offshore sites and, in general, matched observed signatures of inshore and offshore cod. The Bonavista Corridor cod, however, were an exception, having δ18Ooto signatures suggestive of inshore exposure. Our findings provide direct evidence of metapopulation structure in the Northern cod and are consistent with offshore rebuilding having been spurred by dispersal of cod from inshore Smith Sound.

A century of otolith-derived temperature exposure of Icelandic and Norwegian cod (Gadus morhua)

2021 ◽  
Author(s):  
Gotje von Leesen ◽  
Bjarte Bogstad ◽  
Einar Hjörleifsson ◽  
Ulysses S. Ninnemann ◽  
Steven E. Campana
Keyword(s):  
Global Warming ◽  
Oxygen Isotope ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Mixed Effect ◽  
Ambient Temperatures ◽  
Growth Increments ◽  
Future Global Warming ◽  
Temperature Selectivity ◽  
Temperature Exposure

<p>Increasing water temperatures are predicted around the globe with high amplitudes of warming in Subarctic and Arctic regions where Atlantic cod (<em>Gadus morhua</em>) populations currently flourish. We reconstructed population abundance, oxygen isotope and temperature chronologies from otoliths of the two largest cod populations in the world - the Icelandic and the Northeast Arctic (NEA) cod - to determine if their temperature selectivity over the last 100 years was driven by rising water temperatures and/ or changes in abundance. For δ<sup>18</sup>O<sub>otolith </sub>analysis, individual annual growth increments from immature and mature life history stages of cod collected in southern Iceland and the Lofoten area (Norway) were micromilled from adult otoliths. Ambient temperatures of Icelandic and Norwegian cod were reconstructed using otolith δ<sup>18</sup>O. Linear mixed effect models were applied to identify and quantify the density-dependent temperature selectivity of both cod populations. The results indicated that Icelandic cod migrated into warmer waters with increasing abundance (<em>p</em> < 0.05), whereas NEA cod moved into colder waters (<em>p</em> < 0.001). The temperature selectivity of NEA cod was also significantly correlated with water temperatures at 0-200 m depth (<em>p</em> < 0.001), indicating that NEA cod were at least partially exposed to increasing ocean temperatures due to global warming. Stable oxygen isotope and ambient temperature chronologies can be an important tool for sustainable management plans in terms of future global warming as it can be used to predict re-distribution as oceans warm.</p>

Thermoregulatory behaviour in cod: Is the thermal preference in free-ranging adult Atlantic cod affected by food abundance?

2019 ◽  
Vol 76 (9) ◽  
pp. 1515-1527 ◽  
Author(s):  
Björn Björnsson
Keyword(s):  
Growth Rate ◽  
Data Storage ◽  
Gadus Morhua ◽  
Cold Water ◽  
Atlantic Cod ◽  
Vertical Mixing ◽  
Metabolic Energy ◽  
Fat Reserves ◽  
Free Ranging ◽  
Thermoregulatory Behaviour

This study supports the hypothesis that well-fed cod (Gadus morhua) seek higher temperatures to increase growth rate, and poorly fed cod select lower temperatures to save metabolic energy. Depth and temperature of free-ranging adult cod (44–79 cm) were studied with data storage tags as part of a ranching project in an Icelandic fjord. Forage fish were regularly provided at four feeding stations where cod formed distinct “herds” (herd cod) that did not mingle much with the rest of the unconditioned cod in the fjord (wild cod). Several parameters (stomach fullness, liver index (fat reserves), condition factor, and growth rate) indicated that food intake was much greater in herd cod than in wild cod. In August, when the thermocline was well established, the herd cod remained in shallow (15–35 m) and warm water (8–10 °C), whereas the wild cod stayed in deep (80–90 m) and cold water (3–4 °C), but occasionally both groups explored depths and temperatures outside their preferred range. After vertical mixing in autumn when thermoregulation was not possible, the depth difference between the two groups decreased significantly.

Belemnites, clumped isotopes and oxygen fractionation

2020 ◽  
Author(s):  
Madeleine Vickers ◽  
Stefano Bernasconi ◽  
Clemens Ullmann ◽  
Stephen Hesselbo ◽  
Gregory Price ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Isotope Fractionation ◽  
Clumped Isotopes ◽  
Fractionation Factor ◽  
Oxygen Isotope Fractionation ◽  
Temperature Reconstructions ◽  
Life Habits ◽  
Stable Oxygen ◽  
Clumped Isotope ◽  
Low Precipitation

<p>Belemnite calcite has been used extensively for Jurassic and Cretaceous stable oxygen isotope temperature reconstructions since the 1950s. However, with the advent of clumped isotope thermometry, a consistent offset between reconstructed δ<sup>18</sup>O temperatures vs Δ<sub>47</sub> temperatures from the same belemnites has been observed. We investigate the causes of this offset by analyzing samples from the aragonitic phragmacone and calcitic rostrum from the same Cylindroteuthis belemnites, along with other aragonitic benthos, from the Callovian-aged Christian Malford Lagerstätte, U.K. Our new clumped isotope data suggest that the water-calcite <sup>18</sup>O-fractionation factor in belemnite calcite was larger than that of the commonly used δ<sup>18</sup>O thermometry equations (e.g. Kim and O’Neil, 1997), and which is currently observed in other marine calcifiers. Our reconstructions suggest that the oxygen isotope fractionation is compatible with that observed in slow-forming abiotic calcites (e.g. Coplen, 2007) and in rapidly precipitating Travertines (Kele et al. 2015). The application of more established δ<sup>18</sup>O thermometry equations (Kim and O’Neil, 1997) to belemnite calcite for temperature reconstructions has resulted in a consistent underestimation of belemnite calcification temperatures, which has led to erroneous conclusions about belemnite life habits, and underestimation of global temperatures during these greenhouse times. We therefore advocate the use of calcite equations based on low precipitation rate experiments (e.g. Coplen, 2007; Kele et al., 2015) for belemnite rostra temperature reconstructions.</p>

scholarly journals Temperature-dependent fractionation of stable oxygen isotopes in otoliths of juvenile cod (Gadus morhua L.)

2004 ◽  
Vol 61 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Hans Høie ◽  
Erling Otterlei ◽  
Arild Folkvord
Keyword(s):  
Ambient Temperature ◽  
Oxygen Isotope ◽  
Oxygen Isotopes ◽  
Gadus Morhua ◽  
Repeated Measurements ◽  
Stable Oxygen Isotopes ◽  
Temperature Dependent ◽  
Oxygen Isotope Fractionation ◽  
Stable Oxygen ◽  
Left And Right

Abstract Analysis of stable oxygen isotopes in otoliths is a promising technique for estimating the ambient temperature experienced by fish, but consistent equations relating temperature and fractionation of stable oxygen isotopes in otoliths among different fish species are lacking. Juvenile cod were reared at constant temperatures from 6 to 20°C and the sagittal otoliths were analysed for oxygen isotope values. We determined that temperature-dependent fractionation of oxygen isotopes in the otoliths was close to that reported for inorganic aragonite at low temperatures, but there were deviations from oxygen isotope fractionation equations for otoliths of other species. The linear relationship between oxygen isotope value in the cod otoliths and temperature was determined to be: 1000 Ln α = 16.75(103 TK−1) − 27.09. Temperature estimates with 1°C precision at the 95% probability level require a sample size of ≥5 otoliths. Only an insignificant amount of the variance in the data was due to variance between left and right otolith, and due to repeated measurements of otolith subsamples. This study confirms that stable isotope values of cod otoliths can give precise and accurate estimates of the ambient temperature experienced by fish.

Seasonal movements and connectivity of an Atlantic cod (Gadus morhua) spawning component in the western Gulf of Maine

2017 ◽  
Vol 74 (6) ◽  
pp. 1780-1796 ◽  
Author(s):  
Douglas R. Zemeckis ◽  
Chang Liu ◽  
Geoffrey W. Cowles ◽  
Micah J. Dean ◽  
William S. Hoffman ◽  
...  
Keyword(s):  
Population Structure ◽  
Data Storage ◽  
Gadus Morhua ◽  
Fishery Management ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Stock Assessment ◽  
Movement Patterns ◽  
Seasonal Movements ◽  
Spawning Sites

Abstract Movement patterns of marine fishes can have considerable impacts on their population dynamics. A thorough understanding of fish movements is therefore required for informing stock identification, stock assessment, and fishery management. This study investigated the seasonal movements and connectivity of a spring-spawning component of Atlantic cod (Gadus morhua) in the western Gulf of Maine. From 2010 through 2013, spawning cod were sampled within an inshore spawning closure and tagged with conventional tags (n = 2368), acoustic transmitters (n = 106), and archival data storage tags (n = 266). Acoustic receivers were deployed on three inshore spawning sites to test for connectivity among sites. Data from archival tags were used to describe seasonal habitat occupancy and movement patterns via geolocation to statistical areas. Tagging data indicated that cod were primarily residential in the western Gulf of Maine, moving inshore to spawn during the spring (April–July), followed by an offshore migration to their feeding grounds for summer and fall. Cod generally inhabited waters from 45 to 175 m, with the deep offshore basins (>150 m) serving as overwintering habitat. Occupied water temperatures ranged from 4.0 to 13.3 °C, with the coldest temperatures experienced from March through July and the warmest temperatures experienced from September through January. Results provided evidence of spawning site fidelity and connectivity among spawning sites, with some fish visiting multiple spawning sites within or between years. The movements observed during and after the spring-spawning season serve as important mechanisms influencing metapopulation dynamics in the Gulf of Maine region, including both fine- and broad-scale population structure. The improved understanding of cod movement patterns will assist fishery managers in developing management plans, including spawning protection measures, and help to address remaining uncertainties with respect to cod population structure in the Gulf of Maine and other regions.

Sign in / Sign up

Export Citation Format

Share Document