Otolith Weight Research Articles

Otolith morphometry and its role in determining the growth of Periophthalmus chrysospilos distributed in some coastal provinces in the Mekong Delta

This article first provided information on otolith shapes, the variation of otolith weight by sex, fish size, season, and sampling site, and the linear relationship between otolith weight and fish size. A total of 815 Periophthalmus chrysospilos specimens from Duyen Hai, Tra Vinh; Tran De, Soc Trang; Dong Hai, Bac Lieu; and Dam Doi, Ca Mau in the Mekong Delta ranged from 4.20 to 12.50 cm total length and from 1.26 to 16.88 g weight were analysed. The analysis results revealed that Ps. chrysospilos had a square otolith, deeply notched at the anterior apex and flat at the posterior apex. The weight of the left otolith showed a statistical difference according to survey factors, including gender, fish size, season, and sampling site. The otolith weight had a proportional relationship with to the total length, body weight, and head length of mudskippers (r2 =0.7~0.9), which meant that fish size could be predicted from the otolith weight and about 70-90% of the otolith weight of Ps. chrysospilos varied corresponded the growth of the fish.

Growth parameters of the clupeids Limnothrissa miodon and Stolothrissa tanganicae in northern Lake Tanganyika (Bujumbura sub-basin)

The analysis of growth parameters in fish stocks, such as the asymptotic length (L∞) and the curvature parameter (K), is crucial for the estimation of production rates and total mortality rates in fisheries management. Here, we estimated the growth parameters of the clupeids Limnothrissa miodon and Stolothrissa tanganicae in the northern part of Lake Tanganyika (Bujumbura sub-basin). Both species are important targets of pelagic fisheries, but the available estimates are based on scarce size frequency data, and rarely on size as a function of age data. We provide new estimates of L∞ and K based on size as a function of age data, with age being inferred from otolith weights. Furthermore, we reanalyze several existing length frequency datasets using advanced statistical procedures to test if growth parameters estimated by length frequency analysis are consistent with those obtained from size as a function of age. We found that length frequency analysis consistently underestimates L∞ and overestimates K as compared to length-at-age data. We recommend that length-at-age data are collected at a much broader spatial and temporal scale than currently available to advance our understanding of the growth dynamics of these two sardine species. This will improve the assessment of stock productivity of Lake Tanganyika’s pelagic fisheries and the conservation of these economically important fish species.

Determination of the Length-Weight Relationship and Otolith Biometry Characteristics of Scorpaena scrofa (Linnaeus, 1758) in the Çanakkale Region

This study, conducted from October 2019 to September 2021 in the regions of the Çanakkale Strait and the Northern Aegean incleuding, Kepez, Kumkale, Yeniköy, Dardanos, Güzelyalı, Morto Bay, and Saros Bay. 162 individuals of the species Scorpaena scrofa examined. The total weights and lengths of the individuals were recorded. The average otolith weights of female and male individuals were found to be 0.023 g and 0.023 g, respectively (P

Otolith Mass Asymmetry of Pampus candidus (Osteichthyes, Stromatidae) from Iraqi Marine Waters

The otolith mass asymmetry of the fish species Pampus candidus was assessed. The findings indicated a significant level of asymmetry comparison with similar studies on other fish species. The level of asymmetry was shown to increase with the size of the fish, where the utmost estimate of the otolith weight irregularity was obtained. The detected otolith asymmetry may be linked to pollutants in the sampling area.

The utility of otolith weight in growth studies of young-of-year bony bream (Nematalosa erebi), Australia’s most widespread freshwater fish

Otoliths are calcified structures in the inner ear of fish, the analysis of which can be used to derive important life-history characteristics. Otoliths can be used to age young fish by counting daily growth increments visible in the otolith cross-section; however, this is costly and time-consuming. Otolith weight is a potential surrogate for fish age in growth analysis, providing a rapid alternative. Bony bream (Nematalosa erebi) is Australia’s most widespread freshwater fish and an important component of riverine food webs, yet its life-history characteristics are informed by few publications. We investigated the relationship between assumed fish age derived from otolith increments and otolith weight in young-of-year bony bream. We also assessed the utility of otolith weight for use in relative growth rate analysis. Linear modelling showed a significant positive relationship between increment count and otolith weight. Otolith weight when paired with body length was a reliable alternative to increment count, and thus age, for use in relative growth studies. This method can facilitate research into the factors shaping the life history of this ecologically significant species.

Efficacy of otolith morphometry for rapid discrimination of cryptic fishes

The cryptic external morphology of fishes poses challenges for accurate species identification. This study assessed whether the morphometry of otoliths (and body length) could be used as a method to distinguish among closely related, morphologically similar species that are highly valued by commercial or recreational fishers. The otolith morphometry of fishes within four genera (Centroberyx, Lethrinus, Polyprion and Sillago) were compared. Canonical Analysis of Principal Coordinates that included combinations of morphometric variables (i.e., otolith length, width, thickness, weight, and fish length) produced highly accurate species prediction rates ranging from 92.5 to 99.9% across all genera. When different combinations of morphometric variables were modelled, changes in species prediction accuracy rates were minimal (i.e., up to 3%) for the Centroberyx, Polyprion and Sillago species. The exclusion of otolith weight from the multivariate analysis did not significantly decrease prediction accuracy within all four genera. In contrast, the prediction accuracy of the two lethrinids reduced by 7–25% when fish length was excluded, which may be attributable to the larger size attained by L. nebulosus in comparison to its congener L. punctulatus, as well as the very similar ovate shaped otoliths in younger fish of both species. Simplifying data collection to only length-based otolith measurements (and fish length for lethrinids) would provide a more rapid and cost-effective method for discrimination and be more practical when sampling at sea where obtaining accurate weight measurements of otoliths is typically unfeasible. Spatial variation in otolith morphometrics was evident for C. gerrardi, L. punctulatus, P. oxygeneios and S. vittata, which might be attributed to the differences in length distributions of fish samples from different regions. The misclassified specimens within the species groups were notably smaller individuals, suggesting the complexity of otolith shape increases with ontogeny. Hence, further investigation of variations in morphological characteristics, other than otoliths, may be required for the discrimination of cryptic species during the juvenile stage. This study highlights the robustness of multivariate analysis of otolith morphometric data for discriminating closely-related, cryptic species.

Relationship between fish body and sagittal otolith morphometrics in the pool barb Puntius sophore (Hamilton, 1822) from the Ganga and Punpun rivers of Bihar, India

The present study estimated the morphometric relationships between body and sagittal otolith of the economically and nutritionally important pool barb Puntius sophore (Hamilton, 1822). A total of 266 fish specimens were collected monthly from the Ganga and Punpun rivers of Bihar, India from September 2021 to March 2022 Length-weight relationships (LWRs), length frequency distribution, condition factor and otolith aspect ratio were assessed. The fish length and weight ranged from 5.57 cm to 11.17 cm and 1.18 g to 18.98 g, respectively. The b value in LWRs (b>3) were estimated as 3.20 and 3.17 for Ganga and Punpun, respectively. Condition factors indicated optimal growth conditions for this species in both the rivers. The fish and otolith morphometrics showed a positive correlation, and the highest coefficient of determination (R2) was observed between total fish length and otolith weight (R2= 0.942) followed by fish length and otolith length (R2=0.90). All of these relationships are significant to fisheries management and useful for future time series studies on food-feeding habits, stock structure, environmental change and resource conservation. Keywords : Coefficient of determination, Condition factor, Fish otolith, Growth, Length-weight relationship

The asymmetry in the sagitta of four mugilid species obtained from Köyceğiz Lagoon, Aegean Sea, Turkey.

Otolith features such as size and weight were analysed in 656 fish specimens of Chelon auratus, Chelon labrosus, Chelon saliens and Mugil cephalus collected from the Köyceğiz Lagoon System, Aegean Sea, southwest Turkey. The aim was to calculate the asymmetry value of the otolith length (OL), otolith width (OW) and otolith weight (OWe). The asymmetry value of OL was greater than that of OW and OWe. The asymmetry value of the three otolith parameters increased with an increase in the fish's length. The probable cause of asymmetry in the otolith parameters investigated has been determined relative to the variability in growth prompted by ecological impact linked with the disparity in water temperature, salinity, depth and contaminants existing in the Köyceğiz Lagoon System.

Otolith Biometry of Pikeperch <i>Sander lucioperca</i> from the Lakes Region of Turkey

The present study aimed to confirm the existence of relationships between the otolith size (otolith length, otolith breadht, otolith area, and otolith weight) and the size of Sander. lucioperca (L., 1758) from Eğirdir and Beyşehir Lake, Turkey. The length-weight relationships were defined as W = 0.0030L3.386 (R2 = 0.993) for females, W = 0.0032L3.309 (R2 = 0.987) for males from the Eğirdir Lake, and W = 0.0033L3.339 (R2 = 0.977) for females, W = 0.0024L3.410 (R2 = 0.976) for males from the Beyşehir Lake. No significant relations total length and otolith length (OL), otolith breadth (OB), area (A), and otolith weight (OW) were found both the sexes and all the localities. The maximum coefficient of determination were observed between total length and OL, A and OW, while the minimum was observed for OB. The results showed that can be used for the monitoring of stocks in pikeperch populations benefit otolith size.

Otolith Morphometric and Shape Distinction of Three Redfin Species under the Genus Decapterus (Teleostei: Carangidae) from Sulu Sea, Philippines

Otoliths are paired calcified structures in the inner ear of teleosts that function in hearing and balance. In this study, the use of otolith morphometrics and shape analysis were explored to delineate the redfin species under the genus Decapterus from the Sulu Sea, Philippines, namely, Decapterus kurroides, D. smithvanizi, and D. tabl. Results showed that the mean otolith shapes are unique within species (p < 0.001). The otolith size-related (OW—otolith weight, OL—otolith length, OH—otolith height, OA—otolith area, and OP—otolith perimeter) and shape-related (RE—rectangularity, SQ—squareness, EL—ellipticity, RO—roundness, AR—aspect ratio, FF—form factor, CO—compactness, and CI—circularity) morphometric indices also showed significant variations (p < 0.001) among the three species. Distinct regions differentiating D. kurroides from the other two species were seen along the dorsal margin of the otoliths, which was supported by its significantly higher values for OH (size-related index) and RO (shape-related index). In addition, the morphometric indices showed significant variations (p < 0.001), except for RE. Furthermore, it was revealed that the size-related indices were able to separate D. kurroides from the other two species, which turned out to be indifferent. The results provided relevant data on the use of otoliths as an additional confirmatory tool in species delineation of the identified redfin species, and, therefore, offer opportunities of applying the same method in delineation and, eventually, identification of species from other genera, especially those that closely resemble each other.

Distinct Stocks of the Redtail Scad Decapterus kurroides Bleeker, 1855 (Perciformes: Carangidae) from the Northern Sulu and Southern Sibuyan Seas, Philippines Revealed from Otolith Morphometry and Shape Analysis

A recent study was performed to assess the morphometric variation of otoliths of the Decapterus kurroides collected in the northern Sulu and southern Sibuyan seas in delineating fish stocks. Seven of the otolith morphometric descriptors (otolith length, OL; otolith height, OH; otolith weight OW; otolith area, OA; otolith perimeter, OP; ellipticity, EL; and aspect ratio, AR) demonstrated a significant positive correlation with fish length and six (rectangularity, RE; squareness, SQ; roundness, RO; circularity, CI; compactness, CO; and form factor, FF) demonstrated a significant negative correlation. In terms of intraspecific comparisons, almost all the otolith morphometric descriptors were significantly different between the two sites (except RE and OH). Further, principal component (PC) analysis showed that direct otolith morphometric descriptors such as OL, OH, OW, OA, and OP explained 61.71% of the differences (PC1). In contrast, derived otolith descriptors such as EL, AR, and CO explained 22.00% of the variations (PC2) for a total of 83.71% explained variations with the eight otolith morphometric descriptors. Statistics reveal that D. kurroides from the Sibuyan Sea have significantly larger, heavier, and more elliptical otoliths than those from the Sulu Sea. Results suggested that the D. kurroides from Sulu and Sibuyan seas are two different phenotypic stocks. Further studies such as otolith microchemistry, genetics, other life history-based studies, and present exploitation levels should be carried out to supplement the results of this study to fully establish the D. kurroides stock structures within Philippine waters.

Morphological and morphometric features of the abnormal and normal saccular otoliths in flatfishes.

The fish's inner ear consists of three interconnected semicircular canals and otolith organs located in these canals, which are responsible for balance and hearing. Abnormalities in these organs can affect the vital activities of the fish. The main purpose of this study was to determine the morphological and morphometric characteristics of abnormal and normal sagittal otoliths in the four flatfish species (Lepidorhombus boscii, Platichthys flesus, Solea solea, and Pegusa lascaris) sampled from three seas (Aegean Sea, Mediterranean Sea, and Black Sea). Abnormalities in otoliths are investigated using light microscopy, scanning electron microscopy, and Raman spectroscopy. The otolith morphometric measurements and morphology are recorded for abnormal and normal otoliths for each species. It was determined that the four flatfish species examined in the present study showed differences in the morphological features of normal and abnormal otoliths in the blind and eyed sides. In addition, statistical differences were observed when the weight, length, width, perimeter, and area values of normal and abnormal otoliths of all species were compared (p < .05). The four types of saccular otoliths were defined, one normal (type 0) and three abnormal (type 1, type 2, and type 4) for four flatfish species. The current study presents for the first-time abnormal otolith morphology information on blind and eyed side sagittal otoliths in these flatfish species. Abnormalities in the anatomical structures of bony parts such as otoliths in fish may be caused by pollution, nutritional problems, stress, and environmental factors as well as a combination of these.

Diet and condition of juvenile deep-water hake Merluccius paradoxus on the west coast of southern Africa

The composition of the diet of juvenile deep-water hake Merluccius paradoxus is described and compared for three body-condition groups (below-average, average, and above-average). Diet was analysed using three metrics: occurrence, numeric and gravimetric. Juvenile hakes were caught in January and February of 2012 by means of 28 trawl deployments from the RV Dr Fridtjof Nansen between Orange Banks and Hondeklip Bay on the west coast of southern Africa at depths of 30-232 m. The 300 individuals analysed were a representative sample of all juveniles caught (3 114 fish), ranging in length from 52 to 205 mm (average length 107 mm). Their diet consisted of the euphausiid Euphausia lucens, the hyperiid amphipod Themisto gaudichaudii, the stomatopod Pterygosquilla armata capensis, and mesopelagic fishes Maurolicus muelleri and Lampanyctodes hectoris. The only significant difference in diet between the body-condition groups was for euphausiids and hyperiid amphipods in the numeric metric. A new method of assessing fish condition using otolith weight was tested. Because of the large variability in the data and small sample size, this method could not be applied effectively in this study. However, otolith weight has potential as a new fish condition metric when the variability can be lowered.

Usefulness of Otolith Weight for EstimatingAge‐BasedLife History Metrics of Lake Trout

AbstractTo determine if otolith weight can be used to accurately and precisely estimate age‐based life history metrics of Lake TroutSalvelinus namaycushpopulations, we quantified relationships between Lake Trout otolith age and weight sampled from a wide geographic and size range of North American lakes. Separate nonlinear age–weight models for each of 22 surveys (each year within each area or lake) described 82.8% of variation in the relationship between otolith age and weight, whereas separate age–weight models for each of 13 lakes or areas within lakes (years combined) described only 0.4% less variation. Over all surveys, age increased at an average rate of 1.13 years per milligram increase in otolith weight and the otolith weight–age relationship was significantly nonlinear. Age of individual fish could not be estimated accurately from otolith weight alone, although bias of mean age estimated from mean otolith weight was small, whether using survey‐specific or general otolith age–weight relationships. Age at maturity and survival derived from indirect otolith age–weight relationships were estimated with less bias than growth parameters. We conclude that a general model for estimating Lake Trout age from otolith weight may be more useful for maturity and survival analyses that are less susceptible to estimation error of individual (often old) fish than for growth analysis that can be susceptible to estimation error of individual (often old) fish.

Relationship between fish and otolith dimensions of flathead sillago Sillaginopsis panijus (Hamilton, 1822) (Perciformes: Sillaginidae) in the north-western Bay of Bengal

The present study established the fish body and otolith dimension relationships of flathead sillago Sillaginopsis panijus (Hamilton, 1822), to assist the interpretation of growth. A total of 413 specimens were collected fortnightly from September 2018 to August 2019 off north-western Bay of Bengal. The samples ranged between 142–394 mm in total length and16-413.1 g in total weight. With fish growth, positive correlation was observed between the fish and otolith morphometric parameters. The highest coefficient of determination (R2) was observed between total length and otolith weight (R2=0.9198), followed by otolith weight and otolith width (R2=0.896). These results provide baseline information on the dimensional relationship between fish length and otolith size of this species in Indian waters, which will be helpful in future study on the food and feeding habits, growth and stock structure. Keywords: Coefficient of determination, Correlation, Growth rings, Life history, Morphometry, Sagitta

Information on forage fish ages from otoliths collected in avian stomach contents

Otolith analysis allows studying multiple aspects of fish biology, including age estimation; however, otoliths collected from avian stomach content have not been used to estimate the age of ingested fish. We evaluated the potential ability to estimate the age of Pacific sardine (Sardinops sagax) from otoliths collected from blue-footed booby (Sula nebouxii) stomach contents sampled in the Galapagos Islands. Blue-footed boobies were selected because they mostly forage close to their colony (&lt;100 m) and were, therefore, more likely to have almost intact otoliths. To estimate age, we employed three previously developed methods for otoliths. We then related these estimates to the fish's standard length and compared these relations statistically using the Akaike Information Criterion (AIC) to determine which method was most parsimonious. We collected 32 otoliths in relatively good condition, of which we aged 31 with the surface-reading method, 26 with the otolith weight method, and 29 with the posterior otolith length method. Average ages obtained with the otolith methods were 5.6 ± 1.7 yr (± standard deviation), 5.7 ± 2.0 yr, and 3.9 ± 1.5 yr, respectively. Estimates obtained with the otolith weight method had the highest correlation with standard length and the lowest AIC values of the three suggesting it was the best method for aging. Our results indicate that aging otoliths extracted from bird stomachs are possible; however, their use depends on the availability of previously developed methods and how digested the fish are when the birds return to the colony.

Otolith Weight as an Estimator of the Age of Seriola lalandi Valenciennes, 1833 (Carangidae), in the Southeastern Pacific.

Simple SummaryThe healthy management of fishery resources requires the evaluation of a series of population attributes, such as mortality, fecundity, spawning biomass, recruitment and the age at which fish reach sexual maturity. All these attributes depend on the age of fish. Then, the adequate administration and management of these resources require estimators of fish age. Age is estimated by ring counts in the otoliths, which are hard and calcified structures responsible for the balance of fish; however, this is an expensive and time-consuming methodology. An alternative is the use of otolith weight due to its expected relationship with fish age. Yellowtail king fish is a valuable resource, which arrives at the Chilean northern coast in the summer (southern hemisphere). Many aspects of the biology of this fish, such as age and growth, remain unknown. In this study, we estimated the age and growth using otolith weight, which was measured from fish with a known age, and we calculated parameters explaining growth using four different models. The best model was the seasonalized von Bertalanffy growth function, which takes into account that fish do not grow at the same rate year round.The age and growth of fish populations is a critical issue for stock assessment, population dynamics and fishery management. Spawner biomass, mortality, growth, recruitment and age at maturity can be misconstrued if the age estimator is inaccurate. Age can be estimated by annuli count, but this requires expertise and is expensive. Otolith weight (OW) is a good indicator of how long a fish has lived, because OW increases during an individual’s life. Seriola lalandi is a migratory fish and is an important resource for local fishermen in northern Chile. Aspects of its biology, i.e., age and growth, remain unknown, at least for the population annually arriving in northern Chile. Fish of a known age (n = 105; from 5.5 to 25.7 cm in FL) from yellowtail aquaculture facilities at Universidad de Antofagasta allowed us to estimate the growth rate of OW, and fish obtained from local fishermen (n = 71; from 37.9 to 109 cm in FL) allowed us to estimate the age and growth of S. lalandi from the analysis of OW, without the need for calibration. The following four models were fitted with the known ages and fork lengths: the von Bertalanffy growth function, the Gompertz and logistic models and the seasonalized von Bertalanffy growth function. The latter model showed the best adjustment (according to the Akaike information criterion) with the following parameters: L∞, 98.58 cm.; K, 0.59; t0, 0.07; ts, 0.84; and C, 0.97.

The relationship between fish length and otolith size and weight of the two nearly threatened siluriformes species Ailia coila (Ailiidae) and Ompok pabda (Siluridae) collected from the Ganga River at Narora, India

Relationships between fish length and otolith length, width and mass were investigated in the two nearly threatened silurid species (Siluriformes) Ailia coila (Hamilton, 1822) and Ompok pabda Hamilton, 1822) collected from the Ganga River at Narora, India. The relationships between otolith length (OL) and fish total length (TL), otolith width (OWd) and TL, and otolith weight (OWe) and TL are expressed by linear regression models; for A. coila, OL = 0.0291 TL + 0.8541, OWd = 0.0306 TL + 0.2241, OWe = 0.0246 TL + 0.8595, and for O. pabda, OL=0.0643 TL + 1.3848, OWd = 0.0377 TL + 0.7358, OWe = 0.0461 TL + 0.6761. This study symbolizes the first reference available on the relationship of fish size and otolith size and weight for A. coila and O. pabda in the Ganga River at Narora, India. The data obtained are useful for studying the feeding ecology of these fish, whose numbers are declining due to overfishing.

Relationships between length-weight, length-length, and fish length to otolith morphometry in Rita rita (Hamilton, 1822)

The present study deals with fish length-weight, length-length, length-otolith size and length-otolith weight relationships in Rita rita. Specimens (N = 117) were collected monthly from September 2018 to August 2019 from Narora site of the River Ganga, India. The slope (b) in length-weight relationship equation was 2.40, suggesting a negative allometric growth pattern. The Student’s t-test showed no significant differences in the size of right and left otoliths in Rita rita, therefore, a single linear regression based on left otoliths was used. Fish length was plotted against otolith length, otolith height and otolith weight. The linear regression model was found to fit the data well for fish length to otolith size. Fish length was positively correlated with otolith height (R2 = 0.97), otolith length (R2 = 0.94) and otolith weight (R2 = 0.91). The mean value of condition factor was 1.13, which suggested a good condition of the target fish species in the River Ganga. Findings of this study could be used to study the population characteristics of Rita rita, and to explore the food and feeding biology of piscivores based on correlating the otolith morphometry of the prey items to the fish length at age.

Relationship between fish length and otolith dimensions of Yellow striped goatfish, Upeneus vittatus (Forsskal, 1775) along the Indian coast

Otoliths are widely used to estimate the age and growth of fishes and to identify fish species. This information plays a vital role in fisheries management and population dynamics studies. The information about fish length and otolith dimensions relationship of Upeneus vittatus is lacking from the Indian water. In this study, a total of 237 numbers of individuals were collected from October 2018 to March 2019 and left otolith was studied since there were no significant differences between right and left otoliths. The relationships between total length and otolith dimensions were estimated by linear regression and found a strong positive correlation. The maximum correlation was found between fish length and otolith length for Mumbai populations (R² = 0.9342). In contrast, Kakinada populations had the maximum correlation between fish length and otolith width (R² = 0.8957), and Puri populations had the maximum correlation between fish length and otolith weight (R² = 0.9101). Present study found a strong positive correlation between fish length and otolith dimensions. This finding provides new insights into the field and can be used for the growth study, fish population assessment, and fisheries management.