Otolith Analysis Research Articles

Growth and diet of inanga (Galaxias maculatus) within a small New Zealand coastal pond system

ABSTRACT Inanga (Galaxias maculatus) are found in a range of freshwater habitats around much of the Southern Hemisphere. Although they are reasonably well studied within New Zealand, little is known about the populations found in coastal pond systems. This study focussed on inanga diet and population dynamics within a shallow pond complex in coastal Southland, investigating age, growth, distribution, and diet of juvenile inanga over a spring to autumn period. Otolith analysis indicated a three-month period (September to November) during which fish are hatching, with fish that hatched earlier growing more slowly than later fish. Inanga were found in only one location within the pond complex – a site featuring low water nutrient levels and less access by trout. Diet analysis showed high selectivity for chydorids and chironomid larvae, indicating a mixture of both benthic and pelagic foraging. Overall, this study has provided insight into inanga population dynamics in ponds, which have not previously been observed.

Age and growth rate estimations as a basis for assessing the population dynamics of Hydrocynus vittatus Castelnau 1861 in the Sanyati Basin of Lake Kariba, Zimbabwe

AbstractIn early fish life stages, information on their age structure can be used to clarify the effects of environmental changes on their growth and survival, thereby providing an improved understanding of factors affecting their recruitment success. There is currently inadequate understanding of the age structure of Hydrocynus vittatus in the Sanyati Basin of Lake Kariba in Zimbabwe. Accordingly, the present study investigated the age of tigerfish in the Sanyati Basin of Lake Kariba using whole otoliths and scales for comparison. The results indicated ages read on the basis of scales and otoliths of H. vittatus agreed to a larger extent for fish aged one to four years than for fish older than four years. There was a significant difference (χ2 = 8.520, p = .024) in the ages obtained from analysis of scales and otoliths for fish older than four years. The average percentage error and coefficient of variation were found to be 6.03% and 8.1% for whole otoliths, respectively, for the present study. The APE and CV values for scales were 13.81% and 17.41%, respectively. Relatie age data for whole otoliths fit the von Bertalanffy growth model, while that for scales did not fit the von Bertalanffy model, resulting in many outliers and much scatter of the data. The whole otolith parameters for the von Bertalanffy growth curve were L‐infinity = 682.5 mm, k = 0.530 and t0 = 3.19. Based on the results of the present study, it can be concluded in this case that whole otoliths were the best method of ageing tigerfish from Lake Kariba. Accordingly, it is recommended that otoliths be used for ageing tigerfish in Lake Kariba and that scales be used for ageing tigerfish only up to four years in age.

Morphological analysis of otolith among different Bombay duck ( Harpodon nehereus ) populations in China offshore

Morphological analysis of otolith among different Bombay duck ( Harpodon nehereus ) populations in China offshore

IDADE E CRESCIMENTO DE PEIXES DE RIACHO: MÉTODOS E DESAFIOS PARA A OBTENÇÃO DE ESTIMATIVAS ROBUSTAS

Age and growth are key elements on the fish population dynamics, allowing the age structure identification, age of first maturity, mortality rates and longevity calculations, among others. There are also age-based fisheries and ecological models that depends on these studies. It is a challenger field due to the intrinsic variability of growth process at individual and population levels, influenced by endogen and exogen factors. For freshwater fishes, the modal progression analysis, and the analysis of growth rings on scales are widespread applied for age and growth. Like all methods, premises and limitations exist and they must be observed. Otolith analysis is more accurate, unless difficult to stream fishes due to sample size requirements, small otolith size and rings record, specially at the Neotropical region. In this study, sample techniques, material and data acquirement and analyses are presented, focusing stream fishes. Limitations were identified in the results available in the scientific literature due to no consideration of methods premises allied to the mechanic use of software and manuals. For further studies, length frequency analysis, otolith daily rings and experiments are recommended to estimate age and growth of fishes from brooks and streams.

Differentiation of two Chlorophthalmus species Chlorophthalmus corniger (Alcock, 1894) and C. acutifrons (Hiyama, 1940) based on otolith morphometry

A comparative morphometric analysis of otoliths was done to understand the major morphometric characters responsible for differentiating two species of Green-eyes ( Chlorophthalmus corniger and C. acutifrons ) which is one of the dominant fish groups caught in the deep-sea trawling during the exploratory surveys as well as in the by-catch of trawlers targeting deep-sea shrimps at a depth range of 300 – 500 m in the Indian waters. A total of 53 intact, right otoliths (25 and 28 for C. corniger and C. acutifrons , respectively) were considered for the morphometric analysis to differentiate species collected from Andaman Sea. The study extracted four otolith morphometric measurements and five shape indices measured from the otoliths using image analysing software including otolith weight. The otolith morphometric parameters and shape indices showed significant relationship with the fish size were scaled with standard length to remove the influence of fish size from the data. Principal component analysis using scaled otolith morphometric measurements indicated that the first two axes described 84.78 % and 11.80 % of variation, respectively. The PC1 differentiated the species based on ellipticity and otolith weight followed by area and perimeter. C. acutifrons is differentiated from their congener with a more elliptic, heavy otolith with more otolith surface area. One-way PERMANOVA confirmed significant difference in otolith morphology between the species. Present study confirmed the suitability of otolith morphometric analysis in differentiating Chlorophthalmus species which are quite inevitable for taxonomic studies as well as for the better understanding of the species resolution in diet studies.

First approach to the growth and age corroboration of Northeast Atlantic chub mackerel (Scomber colias) in Northern Iberian waters

The growth pattern and parameters of Atlantic chub mackerel in Northern Iberian waters were analysed for the first time in this study, using otolith analyses (direct age estimation-DAE, back-calculation-BC and otolith marginal analyses) and length frequency analyses (Bhattacharya, SLCA and PROJMAT methods), on a time series of data from 2011 to 2017. Two main different growth patterns were obtained, one slower (DAE, BC and PROJMAT) and other faster (Bhattacharya and SLCA). Otolith marginal analyses showed an annual periodicity in the formation of one hyaline and one opaque edge, with a prevalence of the opaque edge from June to December, what in addition to the unimodal distribution of the annuli radii and the obtained back-calculated mean lengths, similar to those obtained by DAE, support the age estimation criteria used here. The growth parameters obtained from DAE (L∞: 45.34, k: 0.28, t0:-1.18) are proposed for the upcoming stock assessment process.

Size, age, and social control of protogynous sex change in the labrid fish Pteragogus aurigarius

The labrid fish Pteragogus aurigarius undergoes protogynous (female-to-male) sex change, with dichromatic and dimorphic differences in sexes. Similar to some other protogynous fishes, this species is polygynous. We report the size and age at which sex change occurs by monthly sampling fishes at Tateyama, central Japan, from 2011 to 2012, and investigate conditions of sex change in rearing experiments from 2013 to 2015. Sexual phases are determined using gonad histology, and ages by otolith analysis. Of 231 sampled specimens, 99 were female, 129 were male, and three were intersexual. Of males, 86 resembled typical males, and are referred to as “normal males (NM)”, and 43 resembled females in color, which we refer to as “males with female appearance (MFA)”. NM sizes exceeded those of female, intersexual and MFA individuals. Because intersexual and MFA individuals did not differ in color or size, they may have recently transitioned to being male. Intersexual and MFA individuals ranged 85–135 mm in total length and 1–3 years in age, and appeared from September to March. Because the spawning season runs from June to September, sex change must occur afterwards. Sex change occurred in solitary females, and larger females held with other females in aquaria, both with and without aquarium partitions. Size hierarchy in social groups may be important for sex change of the largest female to male regardless of the number of individuals present.

Flatfish may be underestimated in the diet of gray seals (Halichoerus grypus)

The United States east coast population of the gray seal (Halichoerus grypus (Fabricius, 1791)) was once hunted to near extirpation, but the population has since rebounded due to protection by the Marine Mammal Protection Act of 1972. Although this population growth is seen as a success by conservationists, others are concerned about the economic and ecological impact of gray seals on New England fisheries. The study objective was to quantify flatfish presence in the diet of gray seals using an analysis of prey DNA in seal scat (molecular scatology). This may reduce a potential bias in other diet analysis methods since flatfish may not be swallowed whole, and therefore, their identifying otoliths may not be present. Scats were collected from Muskeget and Monomoy islands off Cape Cod, Massachusetts, USA, in 2016, 2017, and 2018 and analyzed for flatfish presence using species-specific polymerase chain reaction (PCR) assays and a hard parts analysis using otoliths. Frequency of occurrence for flatfish species from DNA was higher than estimated in previous literature on gray seal diet and a concurrent otolith analysis of the same samples, suggesting that previous analyses may have potentially underestimated the importance of flatfish in the diet.

Chinook salmon exhibit long-term rearing and early marine growth in the Fraser River, British Columbia, a large urban estuary

Estuaries represent a transition zone for salmon migrating from fresh water to marine waters, yet their contribution to juvenile growth is poorly quantified. Here, we use genetic stock identification and otolith analyses to quantify estuarine habitat use by Chinook salmon (Oncorhynchus tshawytscha) — the Pacific salmon species considered most reliant on this habitat — in Canada’s most productive salmon river, the Fraser River. Two years of sampling revealed subyearling migrant (ocean-type) Chinook from the Harrison River to be the estuary’s dominant salmon population throughout the emigration period. These Chinook salmon were caught predominantly in the estuary’s brackish marshes but shifted to more saline habitats as they grew. Otolith analyses indicated that these Chinook salmon have wide-ranging entry timing (from February to May) and longer estuarine residency (weeks to months, mean 41.8 days) than estimated by prior studies, but similar daily growth rates (mean ± SD: 0.57 ± 0.13 mm) across entry dates and residency periods, implying sufficient foraging opportunities throughout the emigration period and habitats. Together, these results suggest that estuarine habitat is more important for early marine growth of subyearling migrant Chinook salmon than previously recognized.

Age and Growth of White Croaker Pennahia argentata in the Southern Sea of Korea by Otolith Analysis

Age and Growth of White Croaker Pennahia argentata in the Southern Sea of Korea by Otolith Analysis

Geochemical analysis of otoliths to study the migratory ecology of tunas

Geochemical analysis of otoliths to study the migratory ecology of tunas

Discrimination of species and populations of the genus Cichla (Cichliformes: Cichlidae) in rivers of the Amazon basin using otolithic morphometry

ABSTRACT The genus Cichla is a highly diverse group, with 16 species already described. Externally, some species are very similar and discriminating between them may be very difficult. Nevertheless, discrimination of fish stocks is essential for management purposes. Morphometric analyses of otoliths have been successfully used to distinguish species and fish stocks, especially in marine environments. This study evaluated whether sagittal otolith shape can be used to discriminate among the species Cichla temensis, C. monoculus, and C. orinocensis, as well as within populations of C. temensis in rivers of the Amazon. Shape indices and Fourier coefficients were used to describe the shape of the otoliths. Among the groups of species, the morphology of the sagittal otolith of C. temensis was totally distinct from the species C. monoculus and C. orinocensis. While among populations of C. temensis, individuals from the Negro and Jatapú Rivers were different, regardless of the methods used. These results confirm the ability to differentiate species and populations by using the morphology of otoliths. However, more research is needed to verify the role of genetic versus environmental and biotic effects, and thus be able to explain the discrimination observed in otoliths.

Individual back-calculated size-at-age based on otoliths from Pacific coral reef fish species

Somatic growth is a critical biological trait for organismal, population, and ecosystem-level processes. Due to its direct link with energetic demands, growth also represents an important parameter to estimate energy and nutrient fluxes. For marine fishes, growth rate information is most frequently derived from sagittal otoliths, and most of the available data stems from studies on temperate species that are targeted by commercial fisheries. Although the analysis of otoliths is a powerful tool to estimate individual growth, the time-consuming nature of otolith processing is one barrier for collection of comprehensive datasets across multiple species. This is especially true for coral reef fishes, which are extremely diverse. Here, we provide back-calculated size-at-age estimates (including measures of uncertainty) based on sagittal otoliths from 710 individuals belonging to 45 coral reef fish species from French Polynesia. In addition, we provide Von Bertalanffy growth parameters which are useful to predict community level biomass production.

Life history plasticity affects the population structure and distribution of the widespread migratory fish Galaxias brevipinnis

Partial migration, or variation in migratory propensity within populations, has been reported across a range of taxa, including fish. Otolith microchemistry has revealed a high degree of life history plasticity in many amphidromous species, with diadromous and non-diadromous recruitment occurring. We examined this plasticity and its effect on population structure, dispersal and recruitment in Galaxias brevipinnis, an amphidromous fish widespread around New Zealand. We used otolith microchemistry analyses to examine recruitment sources and fish surveys to assess abundance and size structure in two large river systems, each containing naturally formed lakes and no obvious physical barriers to migration. Otolith analyses revealed discrete recruitment sources for stream-resident populations, with marine recruitment supporting populations downstream from lakes and exclusively lake-derived recruitment for populations upstream of lakes. Although diadromous G. brevipinnis were abundant within 10km of the sea, the abundance and relative proportion of younger fish declined as distance upstream increased, until a lake was reached, at which point abundance and the proportion of small individuals increased. The results provide a strong indication that supply is limiting recruitment for G. brevipinnis as distance from pelagic larval habitat increases, and that discrete recruitment sources and population structuring exist even within drainages.

A Novel, Efficient Method for Otolith Specimen Preparation Using UV‐Cured Resins

AbstractOtoliths are calcified structures that are located in the inner ears of fish, as in most vertebrates, that are responsible primarily for the perception of gravity, balance, and movement and secondarily of sound detection. Microstructural and chemical analyses of the inner otolith growth layers, called increments, constitute powerful tools for estimating fish age and elucidate many life history and demographic traits of fish populations. Otolith analyses often require the production of a thin cross section that includes the otolith core and all increments formed from birth (core) until the moment of collection (otolith edge) in the same plane of view. Here we report on the suitability of single‐component UV‐cured resins to obtain otolith cross sections for both microstructural examination and chemical analysis by electron probe microanalysis. Embedding blocks that were produced with UV‐cured resins had transparency that was comparable to that of the commonly used two‐component epoxy resins and provided similar adhesion and mechanical support for the otoliths during grinding or cutting with a precision cutter and analysis. In addition, UV‐cured resins offer on‐demand, extremely rapid (minute‐order) hardening that makes them useful in classroom situations in which time for otolith embedding becomes a constraint.

Estimating Age-Specific Natural Mortality for Sandfish in the Eastern Coastal Waters of Korea

To estimate age-specific natural mortality, we proposed an age-structured biomass model with an impulsive dynamical system. In the estimation of natural mortality, we considered growth rate and also reproduction rate, growth, and catch of sandfish, Arctoscopus japonicus. Assuming a linear relationship between observed values of the catch per unit effort (CPUE) and total biomass estimated by the age-structured biomass model, we estimated the age-specific natural mortality using the CPUE and catch data, from 1994 to 2009, for varying values of the assumed initial total biomass in 1994, by selecting the largest coefficient of determination (R2). We suggested the following empirical formula: Mi=qKL∞ln(eK(i+1−t0) − 1eK(i−t0) − 1), which estimated natural mortality of sandfish, and the derived age-specific natural mortality was significantly related to fecundity and growth. The parameters of von Bertalanffy growth equation and a logistic equation of maturity with total length were derived from the data of otolith and gonad analysis of female sandfish collected from 2005 to 2008 and from 2005 to 2006, respectively. We also conducted sensitivity analysis by varying the exponent in the inverse function of total length.

Reconstruction of temperature experienced by Pacific bluefin tuna Thunnus orientalis larvae using SIMS and microvolume CF-IRMS otolith oxygen isotope analyses

This study aimed to reconstruct temperatures experienced during the larval period by adult Pacific bluefin tuna Thunnus orientalis using high-resolution otolith stable oxygen isotope (δ18O) analysis. A novel otolith sample preparation protocol for secondary ion mass spectrometry (SIMS) analysis developed in this study reduced the background noise of SIMS measurements, enabling analyses of >10 times higher resolution around the otolith core compared to previous studies using conventional isotope ratio mass spectrometry (IRMS). The values obtained from SIMS were compared to those obtained by microvolume δ18Ootolith analysis using micromilling and conventional continuous-flow IRMS (CF-IRMS). There was a systematic offset (average 0.41‰ with SIMS resulting in lower values) most likely caused by matrix effects on SIMS δ18Ootolith values that can be calibrated using a strong linear relationship between SIMS and CF-IRMS measurements (r2 = 0.78, p < 0.001). The core-to-edge δ18Ootolith of 5 Pacific bluefin tuna revealed fine-scale seasonal variations in water temperature agreeing with known migration patterns. In addition, the ambient water temperature experienced during larval stages (about 10-20 d post hatch) estimated from otolith core δ18O ranged from 26.7 to 30.7°C, overlapping with temperatures associated with the occurrence of larval Pacific bluefin tuna. Combining SIMS and microvolume CF-IRMS δ18O otolith analyses offers a microscale examination of fish ecology that is not possible with conventional IRMS techniques. This novel method is particularly useful for understanding the early life history of fish that may be affected by climate change and reconstructing a well-resolved migration history for fish species that have small otoliths and/or narrow growth increments.

Otolith Microchemistry of Common Carp Reflects Capture Location and Differentiates Nurseries in an Interconnected Lake System of the North American Midwest

AbstractThe Common Carp Cyprinus carpio is an invasive fish whose populations have grown to ecologically damaging levels in the North American Midwest. It has been shown that some shallow nursery habitats contribute disproportionally to population growth of Common Carp in interconnected Midwestern lake systems. The ability of managers to discriminate which shallow basins are producing Common Carp across these systems could increase the efficacy of management practices aimed at disrupting recruitment. We tested whether adult and juvenile Common Carp collected across an interconnected Midwestern lake system could be distinguished based on the concentrations of 11 trace elements measured in their otoliths using laser ablation and high‐resolution inductively coupled plasma mass spectrometry (n = 157). Elemental concentrations in water were also measured with inductively coupled plasma mass spectrometry and found to differ among sites and between habitats, indicating that variation in otolith microchemistry was likely. Aluminum, barium, copper, iron, potassium, lithium, magnesium, sodium, phosphorus, and strontium in the edge region of otoliths differed significantly among Common Carp from all capture sites. Barium, iron, lithium, manganese, and phosphorus differed significantly among juvenile Common Carp from three nursery basins. Aluminum, barium, copper, iron, potassium, lithium, sodium, phosphorus, and strontium were significantly different between nursery and nonnursery habitats. We then investigated the ability to use these elemental otolith edge signatures to differentiate capture locations and distinguish between locations that are active and putative nursery habitats. Quadratic discriminant analysis could classify otoliths to collection site with an accuracy of 54%. Quadratic discriminant analysis had increased accuracy when restricted to juvenile Common Carp (76%) and when classifying Common Carp to nursery and nonnursery habitat types (87%). Further analysis of otolith and water microchemistry indicates temporal instability and suggests a need to collect a multiyear library of otoliths prior to utilization by managers.

Comparison of Otolith Microstructure of Herring Larvae and Sibling Adults Reared Under Identical Early Life Conditions

Atlantic herring (Clupea harengus) is a euryhaline species, occupying fully marine habitats (35 psu) in the North Atlantic, as well as brackish waters (<20 psu) such as in the adjacent Baltic Sea. We co-reared Atlantic purebreds and Atlantic/Baltic F1 hybrids in two salinity regimes (16 and 35 psu) in a common garden experiment for 3 years until their first maturity. This setup enabled for the first time a direct comparison between adults and their larval siblings at respective salinity regimes in terms of larval growth indicated by otolith microstructure. We validated that otolith microstructure analysis of adult otoliths is reflecting the experienced otolith growth during the larval stage. No major selection in terms of otolith growth had taken place during the juvenile stage, except for one experimental group. Surviving adult Atlantic purebreds reared at 16 psu had higher otolith growth compared to their larval stages. The validation that otolith microstructure analyses of adult herring can reliably be extracted and used to examine larval growth even after several years adds strong support for further use of such analyses. Among the parental generation, Baltic herring had a faster initial otolith growth than Atlantic herring. The growth of their laboratory-reared F1 progeny was intermediate compared to their parents. In general, larval growth of both Atlantic purebreds and Atlantic/Baltic hybrids reared in 16 psu was significantly larger than for those herring reared at 35 psu. There was no significant difference in larval growth between Atlantic purebreds and Atlantic/Baltic hybrids reared at 35 psu, but hybrid larval growth was significantly higher compared to larval growth of Atlantic purebreds at 16 psu. This was not reflected at the adult stage where purebreds were ultimately larger than hybrids (Berg et al., 2018). This indicates the influence and importance of environmental and genetic factors throughout the life of Atlantic herring, along with genetic contributions to phenotypic variability.

Phenotypic/genotypic sex mismatches and temperature-dependent sex determination in a wild population of an Old World atherinid, the cobaltcap silverside Hypoatherina tsurugae.

Several New World atheriniforms have been recognized as temperature-dependent sex determined (TSD) and yet possess a genotypic sex determinant (amhy) which is primarily functional at mid-range temperatures. In contrast, little is known about the sex determination in Old World atheriniforms, even though such knowledge is crucial to understand the evolution of sex determination mechanisms in fishes and to model the effects of global warming and climate change on their populations. This study examined the effects of water temperature on sex determination of an Old World atheriniform, the cobaltcap silverside Hypoatherina tsurugae, in which we recently described an amhy homologue. We first assessed the occurrence of phenotypic/genotypic sex mismatches in wild specimens from Tokyo Bay for three years (2014-2016) and used otolith analysis to estimate their birth dates and approximate thermal history during the presumptive period of sex determination. Phenotypic sex ratios became progressively biased towards males (47.3%-78.2%) during the period and were associated with year-to-year increases in the frequency of XX-males (7.3%-52.0%) and decreases in XY/YY-females (14.5%-0%). The breeding season had similar length but was delayed by about 1month per year between 2014 and 2016, causing larvae to experience higher temperatures during the period of sex determination from year to year. Larval rearing experiments confirmed increased likelihood of feminization and masculinization at low and high temperatures, respectively. The results suggest that cobaltcap silverside has TSD, or more specifically the coexistence of genotypic and environmental sex determinants, and that it affects sex ratios in wild populations.