Otolith Fingerprints Research Articles

Contribution of the nursery areas to the major fishing grounds of the Brazilian sardine (Sardinella brasiliensis) in Southeastern Brazilian Bight inferred from otolith fingerprints

In the late seventies, studies on the population structure of Sardinella brasiliensis suggested the existence of two stocks (23–25°S and 26°S−28°S) based on distinct regional somatic growth rates and spawning areas. This scenario was recently confirmed by using geochemical signatures of whole otoliths combined with basic biological data from two-year-old individuals collected in southeast-south Brazil. However, information about sardine movements and connectivity between their main juvenile recruitment areas and the adult fishing grounds is currently limited. In this work, otolith natal elemental fingerprints (core section) of recruits (age 0+) and adults (age 2+), collected respectively in the main spawning areas (2019) and fishing grounds (2021) were evaluate. Otolith geochemical signatures (element/Ca) of recruits were compared with those of adult fish from the same cohort to estimate connectivity between juvenile recruitment areas (Rio de Janeiro RJ: 22°S, São Paulo SP: 23°S and Santa Catarina SC: 26°S) and regional adult populations captured in the major fishing grounds (22–23°S, 24–25°S and 26–27°S). Uni and multi-elemental signatures showed significant differences for recruits and adult’s individuals. This variability was mainly driven by Ba/Ca, Cu/Ca and Mg/Ca ratios. Pairwise comparisons associated recruits and adults from the northern distribution area (RJ+SP), but differentiated them from those individual from south (SC). The leave-one-out matrix combining otolith fingerprints reassigned the individuals to their original areas with moderate to high accuracy, for both recruits (RJ: 79%, SP: 73% and SC: 67%) and adults (RJ: 75%, SP: 60% and SC: 69%). A multinomial logistic regression suggested that for the 2019 cohort the replenishment of adult populations of S. brasiliensis along the Southeastern Brazilian Bight was mostly derived from the northern recruitment area (RJ+SP=89%). Nonetheless, minor contribution from the southern counterparts to the northern stock was detected (11%), supporting the hypothesis of meta-population structure for this species.

Lebranche mullet Mugil liza population structure and connectivity patterns in the southwest Altantic ocean using a multidisciplinary approach

Previous meristic analysis of the oblique scale counts (OSC) of Mugil liza showed a bimodal pattern within the southern stock, between São Paulo, Brazil (−24°S), and Samborombón Bay, Argentina (−35°S), allowing the identification of two morphotypes (BR1 and BR2). The Brazilian group with lower number of OSC was represented by morphotype 1 (BR1), while the group with higher number of OSC was referred as morphotype 2 (BR2), which could represent distinct subpopulation-units. This study aims at evaluating 1) the population structure of M. liza in Brazilian waters through meristics and body morphometrics from individuals captured by the industrial purse seine fishery, and 2) to assess the possible connectivity between individuals collected off southeast-south Brazil with specimens sampled in Argentinean waters (AR) through otolith shape and microchemistry analyses. Combined meristic and morphometric analyses of fish bodies captured in Brazilian waters allowed to discriminate morphotypes (BR1 and BR2) characterized by different body proportions, head profiles and relative positions of the eye. BR1 presented on average 34 OSC, contrasting with 36 of BR2. For mullets born in two-time distinct intervals, (i) 2008–2011 and (ii) 2011–2014, otolith shape analyses associated AR to BR2, and evidenced a distinct otolith outline from BR1, while multi-elemental otolith core analyses showed no significant differences between AR and BR2. It suggests that the mechanisms responsible for the elemental deposition during the early life history for these two sub-populations (AR + BR2) were significantly different compared to BR1. Univariate analyses of the otolith fingerprints (core and edge) showed higher significant levels in Cd/Ca, Cu/Ca, Fe/Ca, Li/Ca, Mn/Ca, Ni/Ca and Zn/Ca for BR1 compared to AR and BR2. The hereby morpho-meristic data and univariate elemental fingerprints suggest distinct environments inhabited by fish along the western coast of South America. Furthermore, the multi-elemental otolith core results suggested the existence of more than one nursery area for the species. In conclusion, the two morphotypes identified (BR1 and BR2+AR) should be considered as two sub-populations within the mullets southern stock for fisheries management purposes.

Past and Contemporaneous Otolith Fingerprints Reveal Potential Anthropogenic Interferences and Allows Refinement of the Population Structure of Isopisthus parvipinnis in the South Brazil Bight

Simple SummaryOtolith geochemical signatures were important tools used to investigate the population of commercially exploited fish species. Historical and contemporary otolith samples of Isopisthus parvipinnis, Bigtooth corvina, an economically and ecologically important Brazilian fish species, collected in five subareas [São Paulo: North—NSP, Center—CSP and South—SSP; Paraná (PR) and Santa Catarina (SC)] of the shallow waters off the coast of the South Brazil Bight were used in this study. Univariate and multivariate statistical analyses showed spatial differences in otolith chemical composition over the years, suggesting that long-term temporal variability in oceanographic conditions, anthropogenic influence, and climate change on this coastal ecosystem influenced the geochemical signatures. Moreover, these results also confirm that I. parvipinnis is not a single and homogeneous fish stock in this geographic area, supporting the existence of a metapopulation structure scenario and corroborating previous studies that used alternative, complementary phenotypic tags.In this study, otolith geochemical signatures (Element:Ca ratios) were used to investigate the long-term spatial shifts of the population structure of Isopisthus parvipinnis, Bigtooth corvina, an economically and ecologically important Brazilian fish species. Two-hundred and ninety-seven juvenile individuals from historical (1975) and contemporary (2018/2019) samples were collected in five subareas [São Paulo: North—NSP, Center—CSP and South—SSP; Paraná (PR) and Santa Catarina (SC)] of the shallow waters off the coast of the South Brazil Bight were analyzed. The main informative single elements were Co:Ca, Cu:Ca, Li:Ca, Mg:Ca, Mn:Ca, Ni:Ca, Na:Ca, and Rb:Ca. Multivariate analysis showed spatial differences in otolith chemical composition over the years. Samples from 1975 presented an overall low reclassification rate (58%), suggesting the existence of two population units: (1) SP + PR; and (2) SC. However, samples from 2018/2019 discriminated four distinct population units with a good overall reclassification (80%): (1) NSP; (2) CSP; (3) SSP + PR; and (4) SC. This spatial differentiation on the geochemical signatures probably reflects the effects of long-term temporal variability in oceanographic conditions, anthropogenic influence, and climate change on this coastal ecosystem. The data also corroborate and refines the population structure scenario of I. parvipinnis recently described using complementary phenotypic tags.

Potential linkages between juvenile nurseries and exploited populations of Mulloway (Argyrosomus japonicus), explored using otolith chemistry

Many exploited coastal species rely on estuarine nurseries, however, the importance of different estuaries and their contribution to exploited populations can vary. Identification of connectivity between source nurseries and exploited populations is important for effective habitat and fishery management. We present a case study which employs otolith chemistry to investigate source-sink population dynamics across broad spatial scales for an exploited migratory sciaenid, Mulloway (Argyrosomus japonicus). Specifically, we compared the otolith chemical fingerprints of juveniles in putative estuarine nurseries across south-eastern Australia with the sub-yearling chemical fingerprints of post-recruited fish in the exploited component of the stock. Multinomial Logistic Regression (MLR) suggested that two of the eight estuarine nurseries sampled were particularly important sources of Mulloway recruits, and there was strong evidence of stock mixing which exceeded that expected from historic tag-recapture studies. However, there was some uncertainty in the patterns resolved. Variation in otolith signatures between the known-source juveniles and post-recruit fish may be explained by inter-annual variability in these systems, caused by extensive flooding on the central and northern-NSW coast during the study period. These events contributed considerable extrinsic variation to the chemical composition, influencing the lack of overlap between otolith chemistry of putative nurseries and sub-yearling otolith chemistry of exploited fish. The approach presented highlights the importance of considering inter-annual variability when examining source-sink relationships in long-lived species, but the use of otolith fingerprints shows promise for evaluating these questions for both Mulloway and other exploited fish species.

Otolith Fingerprints and Tissue Stable Isotope Information Enable Allocation of Juvenile Fishes to Different Nursery Areas

Integrated otolith chemistry and muscle tissue stable isotope analyses were performed to allocate juvenile Diplodus puntazzo and Diplodus vulgaris to nurseries in the Adriatic Sea. Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) was used to quantify the concentrations of chemical elements in the otoliths. Fish muscle samples were analysed for δ13C and δ15N. In general, Ba/Ca and Sr/Ca ratios and isotopes varied between sites and species. Values of δ13C and δ15N were significantly different between species and sites. Multivariate analysis detected a significant difference in the element signature between species while there was no evidence for a significant interaction for sites. A clear pattern across the four groups of interest, D. puntazzo_Estuary > D. vulgaris_Estuary > D. puntazzo_Coastal > D. vulgaris_Coastal, following decreases in δ13C, and increases in δ15N were found. It seems that these species are feeding on the same local food web within more productive estuarine site while at costal site, feeding segregation among investigated species is evident. Both species were re-allocated correctly to the estuarine waters based on the otolith chemistry and stable isotopes information and higher value of δ15N. Combining otolith chemistry with tissue isotope ratios of juvenile fish provided complementary information on nursery habitat use at different spatial scales and elucidated ecological and environmental linkages.

Otolith fingerprints reveals potential pollution exposure of newly settled juvenile Sparus aurata

Coastal ecosystems are increasingly threatened by a wide range of human activities. Fish otolith chemistry, by creating a unique specific signature, can be used as a natural tag for determining life stage dispersal, spatial connectivity and population structure. In this study, we tested whether differences in otolith composition among juveniles of gilthead sea bream, Sparus aurata, could enable their proper allocation to polluted areas based on higher concentrations of elements related to contaminants. Otoliths were embedded, sectioned and analysed by LA-ICP-MS in line scan mode. Multivariate analysis confirmed clear separation between sites and elements. Samples from the site under the strongest anthropogenic impact from industrial and agricultural river input were characterized by higher values of Pb/Ca and Zn/Ca. However, these relatively low values likely do not have a negative effect on S. aurata recruitment, though they could serve for identifying the contribution of polluted nurseries to stock dynamics.

Evaluation of the body morphology and meristics, otolith shape analyses and otolith micro-chemical variability of Lebranche mullet Mugil liza in the Southeast Atlantic Ocean as a tool for the identification of population subunits

Evaluation of the body morphology and meristics, otolith shape analyses and otolith micro-chemical variability of Lebranche mullet Mugil liza in the Southeast Atlantic Ocean as a tool for the identification of population subunits

Otolith fingerprints as natural tags to identify juvenile fish life in ports

The construction of ports has caused substantial habitat destruction in coastal areas previously used as nursery grounds by many fish species, with consequences to fish stocks. These artificial coastal areas might provide alternative nursery habitats for several species for juvenile fish abundances and growth in ports, although their contribution to adult stocks had never been estimated. The variability of otolith composition in the juveniles of two Diplodus species was investigated in three contrasting port areas and two adjacent coastal juvenile habitats of the Bay of Toulon (northwestern Mediterranean) in order to determine the possible use of otolith fingerprints as natural tags for the identification of juvenile fishes in ports. The global accuracy of discrimination between ports and coastal areas was very high (94%) irrespective of species, suggesting that otolith fingerprints can be used with confidence to retrospectively identify past residency in the ports of this bay. However, Ba was systematically the most discriminating element, since its concentrations in otoliths were generally higher outside ports than in inside them, probably due to river runoff. Moreover, otolith signatures varied greatly by species and between sampling sites. Furthermore, although Cu and Pb concentrations in water were at least 2.3–34-fold higher inside ports than outside, this was not consistently reflected in fish otoliths, confirming that spatial differences in otolith concentrations depend on the species and do not directly reflect differences in environmental contamination levels. Therefore, it seems unlikely that otolith microchemistry could provide a universal fingerprint capable of discriminating ports from other coastal areas. Nevertheless, the contribution of ports to adult fish populations can be determined well by establishing a library of otolith fingerprints for all juvenile habitats.

Estimating contributions from nursery areas to fish stocks in freshwater systems using otolith fingerprints: The case of the streaked prochilod in the La Plata Basin (South America)

AbstractStock composition studies using otolith fingerprints have scarcely been developed in freshwater systems. In this context, the La Plata Basin is the second largest fluvial‐marine system of South America, where Prochilodus lineatus is the most important fishery resource. Despite the basin importance, estimation of mixed stock composition has not been explored yet. In this paper, the contribution of the two main nursery areas to two fishing stocks (Uruguay and Paraná rivers) of P. lineatus was evaluated using otolith's core microchemistry, considering two groups: subadult (2 years) and adult (4 years). Estimates were made using two maximum likelihood methods. Chemical composition of young‐of‐year fish caught in nursery areas in 2010 was used as baseline of the models, whereas chemical composition of the core of subadult and adult otoliths was used as sample of unknown origin. Results suggest that the subadult stock from Paraná was not mixed (contribution ~ 100%), whereas the stock from Uruguay had a contribution from the Paraná nursery (1.5 ± 1.2–17.9 ± 3.96%). For the adults, the degree of mixing increased and the contribution from both nursery areas to the Paraná and Uruguay stocks varied between 14.8 ± 4.18% and 85.2 ± 4.18%, respectively. The potential application of otolith fingerprints and maximum likelihood mixture models is here highlighted for determining the relative importance of recruitment sources of fish in the La Plata Basin. Because the contributions of the different nursery areas shared among several nations in turn affect the composition of internationally shared stocks, comprehensive management agreements at the basin level are necessary.

Otolith edge fingerprints as approach for stock identification of Genidens barbus

The purpose of this paper is to assess the use of multi-elemental otolith fingerprints as a tool to delimit catfish Genidens barbus fish stocks in four estuaries from the southwestern Atlantic Ocean. Barium:Calcium (Ca), Magnesium:Ca, Manganese:Ca, Sodium:Ca and Strontium:Ca ratios in the otolith edge were determined by LA-ICPMS. PERMANOVA analysis reveal significant differences in the multi-element signatures among estuaries (p = 0.0001–0.002). Reclassification rates of quadratic discriminant analysis are high, averaging 89.9% (78–100%). The new data presented here show that the otolith chemistry is a potential tool for stock identification, and indicates the presence of at least four stocks which should probably be handled independently.

Otolith fingerprints of the coral reef fish Stegastes fuscus in southeast Brazil: a useful tool for population and connectivity studies

Otolith fingerprinting is a useful tool in determining the population structure, movement patterns and connectivity among fish habitats. Damselfish, Stegastes fuscus, is a highly abundant reef fish species in the Brazilian coasts. It has been assessed as least concern species according with the IUCN Red List. One hundred and twenty adults, ranging from 85 to 120 mm standard length, were collected in April 2013 by spear fishing in six coastal islands located on Cananéia, Paranaguá, Guaratuba and Babitonga bays, southeast Brazil. Elemental and isotopic signatures of whole sagittae were determined by inductively coupled plasma mass spectrometry and isotope ratio mass spectrometry, respectively. Element:calcium (Sr:Ca, Ba:Ca, Mn:Ca and Mg:Ca) and isotopic ratios (δ18O and δ13C) were analyzed with univariate and multivariate statistics to determine whether these fingerprints can be used to assess the degree of separation between the individuals of these geographic locations. Whole otolith fingerprints representative of the fish entire life-history gave distinct small scale spatial signatures confirming that S. fuscus is a sedentary reef species. Classification accuracy rate obtained from quadratic discriminant function analysis of whole otolith chemistry data was relatively high (71% of mean accuracy percentage). Furthermore canonical analysis of principal coordinates from otolith signatures showed the existence of three regional groups probably a consequence of the similarity of the major estuarine systems that characterize the environment of the nearby coastal islands where fish were collected. This study suggests that otoliths can be used to study the population structure and assess connectivity of the damselfish, providing new knowledge to adequately manage this species.

Otolith fingerprints reveal stock discrimination of Sperata seenghala inhabiting the Gangetic river system

Variations in elemental concentrations of otoliths were used to study the probable stock(s) of Sperata seenghala in the Gangetic river system. Fifteen trace elements from whole sagittal otoliths were analysed using inductively coupled plasma–atomic emission spectrometry. Strontium, barium, lithium, copper, iron, lead, zinc, manganese, nickel (P 0.01). Chromium and cadmium were not detected in the otoliths of the fish from Narora site on the river Ganga. Discriminant function analysis using cross-validation classification assigned individuals to their site of sampling origin with a mean classification accuracy of 83.2 %. The detected site-specific elemental differences in S. seenghala otoliths indicate a high level of site-fidelity in relation to their habitat areas. Thus target fish population from these sites can be regarded as separate stocks.

Multi-element otolith fingerprints unravel sea−lagoon lifetime migrations of gilthead sea bream Sparus aurata

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 444:175-194 (2012) - DOI: https://doi.org/10.3354/meps09444 Multi-element otolith fingerprints unravel sea−lagoon lifetime migrations of gilthead sea bream Sparus aurata Lény Mercier1, David Mouillot1, Olivier Bruguier2, Laurent Vigliola3, Audrey M. Darnaude1,* 1ECOSYM, UMR 5119, Université Montpellier 2, Place Eugène Bataillon 34095, Montpellier Cedex 5, France 2Géosciences Montpellier, UMR 5243, Université Montpellier 2, Place Eugène Bataillon 34095, Montpellier Cedex 5, France 3IRD, UR 227 CoReUs, Centre IRD de Nouméa, BP A5, 98848 Nouméa, New Caledonia *Email: ­audrey.darnaude@univ-montp2.fr ABSTRACT: Precise knowledge of lifetime migrations is vital in exploited fish species, since all essential habitats must be protected to maintain sustainable stock levels. The present study used multi-element otolith fingerprints of the gilthead sea bream Sparus aurata (L.) to discriminate its main juvenile and adult habitats in the Languedoc-Roussillon region (Gulf of Lions, northwest Mediterranean) and infer the lifetime migrations of 12 individuals from the area (11 from the present day and 1 from the Roman era). This allowed for the first time the identification of key habitats for the successful completion of the species’ life cycle in the Gulf of Lions, and the connectivity between them. Our results revealed that lagoon use by S. aurata is probably ancient (>2500 yr) and confirmed its current commonness. Yet, although most observed migration patterns were in accordance with the migratory behavior previously described for the species, strong inter-individual variations and new patterns in habitat use were detected. At the juvenile stage, a preference for shallow lagoons with low salinities was evidenced. Nevertheless, the first year of life can also be successfully completed in marine conditions. At the adult stage, lagoon use was shown to occur until at least age 4 yr, with periods of lagoon residency of up to 11 mo in a year, often including winter months. Because overwintering in the lagoons was previously thought to be impossible for S. aurata due to low temperatures, this finding has important implications for future stock management, especially since the species breeds in winter. KEY WORDS: Otolith microchemistry · Trace elements · Random forest · Key habitats · Gulf of Lions Full text in pdf format PreviousNextCite this article as: Mercier L, Mouillot D, Bruguier O, Vigliola L, Darnaude AM (2012) Multi-element otolith fingerprints unravel sea−lagoon lifetime migrations of gilthead sea bream Sparus aurata. Mar Ecol Prog Ser 444:175-194. https://doi.org/10.3354/meps09444 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 444. Online publication date: January 10, 2012 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2012 Inter-Research.

Selecting statistical models and variable combinations for optimal classification using otolith microchemistry

Reliable assessment of fish origin is of critical importance for exploited species, since nursery areas must be identified and protected to maintain recruitment to the adult stock. During the last two decades, otolith chemical signatures (or "fingerprints") have been increasingly used as tools to discriminate between coastal habitats. However, correct assessment of fish origin from otolith fingerprints depends on various environmental and methodological parameters, including the choice of the statistical method used to assign fish to unknown origin. Among the available methods of classification, Linear Discriminant Analysis (LDA) is the most frequently used, although it assumes data are multivariate normal with homogeneous within-group dispersions, conditions that are not always met by otolith chemical data, even after transformation. Other less constrained classification methods are available, but there is a current lack of comparative analysis in applications to otolith microchemistry. Here, we assessed stock identification accuracy for four classification methods (LDA, Quadratic Discriminant Analysis [QDA], Random Forests [RF], and Artificial Neural Networks [ANN]), through the use of three distinct data sets. In each case, all possible combinations of chemical elements were examined to identify the elements to be used for optimal accuracy in fish assignment to their actual origin. Our study shows that accuracy differs according to the model and the number of elements considered. Best combinations did not include all the elements measured, and it was not possible to define an ad hoc multielement combination for accurate site discrimination. Among all the models tested, RF and ANN performed best, especially for complex data sets (e.g., with numerous fish species and/or chemical elements involved). However, for these data, RF was less time-consuming and more interpretable than ANN, and far more efficient and less demanding in terms of assumptions than LDA or QDA. Therefore, when LDA and QDA assumptions cannot be reached, the use of machine learning methods, such as RF, should be preferred for stock assessment and nursery identification based on otolith microchemistry, especially when data set include multispecific otolith signatures and/or many chemical elements.

Interspecific variations of otolith chemistry in estuarine fish nurseries

Otolith chemical composition differed between juveniles of five fish species (Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax) in nursery areas of six estuaries along the Portuguese coast (Douro, Ria de Aveiro, Mondego, Tejo, Sado and Mira). Spatially consistent patterns in the concentration of some elements were responsible for differences between species. Discrimination of estuaries using data from all species simultaneously averaged 44·7% of correctly classified cases, whilst discrimination of species averaged 76·2%. Moreover, species‐related patterns in otolith fingerprints were highlighted when comparing species for each estuarine nursery area, with intra estuarine species discrimination averages ranging from 86·2 to 100·0%. Similarities in the otolith elemental fingerprints were larger between species with close phylogeny and ecology, particularly between flatfish and perciform species. In addition to the differences in physiological regulation of species, specific microhabitat use in a common environment was suggested as a relevant factor for the differentiation of otolith chemistry among species occurring in the same locations. Despite positive results in specific estuaries, variation in otolith composition limited the use of species as proxies to classify others to their system of origin.

Discriminating estuarine nurseries for five fish species through otolith elemental fingerprints

Chemical composition of otoliths may provide valuable information in establishing con- nectivity between nursery grounds and marine coastal stocks. Juveniles of the commercially impor- tant fish species Solea solea, S. senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax were captured in 8 estuarine nursery grounds along the Portuguese coast in July 2005. Con- centrations of Li, Na, Mg, K, Mn, Ni, Cu, Zn, Sr, Cd, Ba and Pb were determined in whole juvenile otoliths using solution-based inductively coupled plasma mass spectrometry. Significant differences in the concentration of several elements were found between estuaries and species using ANOVA and MANOVA. Linear discriminant function analysis classified otolith fingerprints between estuaries for all species with good cross-validated results. Depending on the species, 70.2 to 92.0% of individ- uals were correctly assigned to their estuary of origin, with discrimination success varying with species, estuaries and number of estuaries in the analysis. Since accurate classification of juvenile fish to their nursery estuary was achieved, fingerprint analysis can be used as a natural habitat tag in assigning adult fish to their estuarine nursery. Ultimately the connectivity between Portuguese estuarine nursery grounds and coastal areas may be estimated, with possible implications for future fisheries and coastal management plans.