Relationship between Otolith and Fish Sizes: Validation Using Their 3D Shape Analysis

Relationships between fish length and otolith length, width, and weight were studied in three lethrinid species Lethrinus borbonicus Valenciennes 1830, Lethrinus lentjan (Lacepède 1802), and Lethrinus mahsena (Fabricius, 1775) collected from the south of the Red Sea at the costs of the Republic of Yemen. These relationships are important for future research into the biology of these species, including their diet, feeding habits, age, and growth. Linear regression models were used to investigate the relationships between otolith length and total fish length (TL), otolith weight and TL, and otolith width and TL. A non-linear regression model was used to investigate the relationship between otolith weight and TL. The morphometric relationships indicated that otolith length exhibited the highest correlation with total fish length among the other two otolith variables. This study is the first to examine the relationship between fish size and otolith size and weight in three lethrinid species obtained from the coast of the Red Sea in Yemen.

Relationships between fish length and otolith length and width were examined in the blueline snapper Lutjanus coeruleolineatus (Lutjanidae) collected from the coasts of Oman, Arabian Sea. The values of exponent b from the relationships between fish total length and otolith length and total length and otolith width were estimated representing the close fitness of otolith size with fish size. Both relationships were statistically significant, which means both otolith length and width can be used to retrieve the fish original size. The analysis of covariance (ANCOVA) was used to test the effect of the categorical factor of species in the fish length and otolith length relationship. This study represents the first reference available on the relationship of fish size and otolith size for L. coeruleolineatus in the Arabian Sea area. Results from this study will offer original data on quantitative biometric relationships between body and otolith measurements of fish species in Arabian Sea region. By obtaining the mathematical model showing the relationship of the otolith size and fish length will enable fisheries biologists to know the size of the fish that has been eaten an information which important for fish biologists.

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.

Reliable and detailed knowledge regarding the relationship between otolith size and the size of fish is important for fisheries management and for ecological studies on predicting fish size and on predator–prey interactions. Therefore, these relationships are estimated for three sprat (genus Clupeonella) species, including C. caspia, C. engrauliformis and C. grimmi from the Caspian Sea. The relative size and mass of the otoliths corrected for body size and mass were also estimated for the three sprat species. After biometry of collected specimens, the Sagittal otoliths were extracted from the cranium of collected specimens and photographed. Photos were used to estimate length and width of otoliths. The results revealed significant relationships between otolith length and width vs. fish length and otolith mass vs. body mass in all three species (r2 > 0.5). The higher coefficient of determination (r2) for relationships between total length (fish) – Otolith length and width was concluded in comparison with relationships between fish mass and otolith mass in the studied sprat species. Otoliths of C. grimmi showed the highest relative length and were significantly (P < 0.05) heavier than sagittal otoliths of two other sprat species. There is no previous report on size–mass relationships between fish and otolith measurements among the three studied sprat species. These estimated equations can be used in back-calculation studies, especially for these three sprats as the dominant prey for piscivorous predators such as Caspian seals and sturgeons, in their habitats.

In this study, relationships between fish length and otolith length, width and weight of Sardinella sindensis from Bandar Lengeh and Qeshm Island, Persian Gulf were analyzed. In total, 128 and 120 fishes collected from Commercial catches during March 2011-February 2012 in the Bandar Lengeh and Qeshm Island repectively. There were no significant differences between left and right otolith (t-test, P>0.05) and between males and females otolith (ANCOVA, P>0.05). For these reasons, only right otoliths were used for next analysis and data of each two sex were pooled. Relationships between length and otolith length, width and weight described by linear regression models and high correlation showed for all relationships. The highest correlation was between fish length and otolith length (Bandar Lengeh, R2=0.8722; Qeshm Island, R2=0.8661) and relashionship between fish length and otolith width was less correlation than other relathionships (Bandar Lengeh, R2=0.7355; Qeshm Island, R2=0.7275). These results showed that fish length and otolith growth have a positive relashionship, so can be useful tools for determining fish species, size and age.

The length-weight relationships and the regressions between otolith size (length and width) and fish length of some mesopelagic and bathypelagic fishes living in the central Mediterranean Sea were provided. Images and morphological description of otoliths (sagittae) from 16 species belonging to the families of Gonostomatidae (1), Microstomatidae (2), Myctophidae (8), Phosichthyidae (2), Sternoptychidae (2) and Stomiidae (1) were given. The length-weight relationship showed an isometric growth in 13 species. No differences between right and left otolith sizes were detected by t-test, so a single linear regression was plotted against standard length (SL) for otolith length (OL) and otolith width (OW). Data fitted well to the regression model for both OL and OW to SL, for each species (R2 > 0.8). These relationships offer a helpful tool in feeding studies and also provide support to palaeontologists in their research on fish fossils.

This paper contributed data on otoliths morphometry and their relationships with the size of Periophthalmodon septemradiatus . A total of 135 specimens (86 males and 49 females) were collected from the five sites in branches of the Bassac River, Vietnam. Length, width, and weight of left otoliths were similar to those of the right otoliths. These otolith parameters of did not change with gender, but vary significantly in five sites, reaching the highest point in the upstream of Bassac River in Binh Duc, Long Xuyen, An Giang where fish total length and body weight reached the highest values. The otolith length, width, and weight had strong relationships with fish total length and body weight due to the high value of determination coefficients ( r 2 ). Among the three dimensions of otoliths, otolith length was the most positive relationship with fish size since r 2 of this regression reaches the highest value. The results suggested that otolith dimensions could be used for fish size determination.

Otolith morphology analysis is one of the main tools used for fish or fish stock identification. Moreover, otolith shape can also be used in animal dietary studies (stomach content) for the identification of prey fishes and their size according to the relationship between fish and otolith sizes. In the present study, the relationship between fish length and otolith morphological dimensions was investigated for the sabre squirrelfish, Sargocentron spiniferum (Forsskål, 1775) (family: Holocentridae). Samples of 185 fish were collected from the coast of the Red Sea, Egypt. To analyze the relationship between fish and otolith, otolith morphometric measurements (length, width, area, perimeter, weight, sulcus, and ostium) and shape factors (aspect ratio, compactness, form factor, rectangularity, roundness, ellipticity, squareness) describing the outline shape were extracted using image analysis. Generalized linear models were applied for the relationship between body length and each otolith morphology feature. From the relationships between the total length of fish and fourteen morphology features, only otolith length, caudal length, and squareness were significantly correlated with fish size. Our results provide more information for the relationship between fish length and otolith morphometric features.

Relationships between fish length and otolith length, width and mass were examined in the Australian anchovy Engraulis australis (White, 1790) recovered from the food of Gannet examined from colonies at islands of Horuhoru Rock and Mahuki Islands in the Hauraki Gulf, New Zealand. The relationships between otolith length- fish total length (TL), otolith-weight-TL, and otolith-width-TL were investigated by means of non-linear regression models (TL = 0.54 OL 16.86, TL = 4.39 OW 7.61 and TL = 26.19 OWe 2.2). This study characterizes the first reference available on the relationship of fish size and otolith size and weight for E. australis obtained from bird’s food in the Pacific Ocean region

Relations between fish size and otolith size of stargazer (Uranoscopus scaber) were studied in this study. A total of 268 samples were obtained from the coastal shelf of Ordu Province (south-eastern Black Sea) by commercial trawling and gillnetting operations. It was found that there were high correlations between fish size and otolith size. It was concluded that all measurable body sizes could be effectively used to estimate otolith length, width and weight. Similarly, estimation of the age of fish from otolith length and weight was also possible with high significance. The results of this research will be useful for others working on this fish, being a first study in the field. The ages of stargazer were determined between 0+ and 4+. Relationships were determined as OW = 0.001 × OWi2.76, OW = 0.35 × 10−3 × OL2.54 with high correlation coefficients of r = 0.965 and r = 0.949, respectively.

In this study, total length (TL) – total weight (TW) relationship, age, growth, and the morphometric relationships of otolith between otolith length (OL) and otolith weight (OW), total length (TL) and otolith length (OL), total weight (TW) and otolith length (OL), otolith width (OWi) and otolith length (OL) of Pagrus pagrus were investigated in Saros Bay (North Aegean Sea). A total of 100 specimens were measured as minimum TL 9.6 cm, maximum TL 44.4 cm, and minimum TW 17.1 g and maximum TW 1372.5 g. A total of 55 otoliths were measured as minimum OL 0.52 cm, maximum OL 1.17 cm, minimum OW 0.0181 g, and maximum OW 0.1456 g. The relationships between TL and TW, OL and OW, TL and OL, OL and TW, OL and OWi were determined as TW=0.021*TL2.885 (r2=0.98), OW=0.105*OL2.609 (r2=0.929), OL=0.024*TL+0.249 (r2=0.839), TW=0.235*OL0.237 (r2=0.814), and OWi=0.501*OL+0.116 (r2=0.832), respectively. Maximum age was 9 years for P. pagrus and von Bertalanffy growth parameters were estimated as L∞=51.59 cm, K=0.12 year-1 and t0=-1.13 year.

Fluctuating asymmetry was calculated for the otolith length, width, and thickness in the adult fish Liza klunzingeri . The results showed that the level of asymmetry of the otolith width was the highest among the three asymmetry values obtained. The asymmetry value was zero for the otolith thickness. The results also showed that the lowest level of asymmetry in the otolith length was at the fish length ranging between 14.1-15.0 mm, and the higest at the fish length 17.1-18.0 mm, while asymmetry was zero at fish length 12.1-13.0. For the otolith width, the lowest level of asymmetry is at the fish length ranging between 13.1-14.0 mm and the highest at the fish length ranging between 17.1-18.0 mm while the value of asymmetry was zero in the fish length ranging from 12.1-13.0 mm. The possible cause of the asymmetry in this species has been discussed in relation to the general presence of pollutants in the area. An increasing asymmetry with the fish length (age) was noticed.

Fluctuating asymmetry was calculated for the otolith length and width of the adult fishes Chlorurus sordidus and Hipposcarus harid . The results showed that the level of asymmetry of the otolith length was the higher than that of the otolith width in both species. For C. sordidus , the lowest level of asymmetry in the otolith length was at the fish total length ranging between 150-260 mm, and the highest at the fish total length 160-260 mm. For the otolith width, the highest level of asymmetry is at the fish length ranging between 24-26 mm and it has zero value in the other length groups. For H. harid , the lowest level of asymmetry in the otolith length was at the fish length ranging between 160-170 mm, and the highest at the fish length 240-260 mm. For the otolith width, the highest level of asymmetry is at the fish length ranging between 240-260 mm and it has zero value in the other length groups. The possible cause of the asymmetry in these species has been discussed in relation to the general presence of pollutants in the area. An increasing asymmetry with the fish length (age) was noticed.

This study aims to determine the biometric comparison of otoliths of Banggai cardinal fish based on gender and to determine the comparison of otolith biometrics at two locations in the Waters Front of TPI Dudepo Kab. South Bolaang Mongondow and in the Lembeh Strait, Bitung City. Data collection in the field using the roaming survey method. Fishing is done by snorkelling, catching a minimum of 50 individuals representing each size class using Chang net/Sibu fishing gear. The differences in otoliths in male and female sexes have seven different otolith characters in otolith length (OL), otolith width (OW), otolith area (OA) and otolith perimeter (OP), roundness (Rnd), ellipticity (Ell) and aspect ratio (Ar), and three characters that do not show significant differences, namely form factor (Ff), circularity (Cir), rectangularity (Rec). The differences in otoliths based on location in front of the Dudepo TPI and in the Lembeh Strait have seven different otolith characters in otolith length (OL), otolith width (OW), otolith area (OA) and otolith perimeter (OP), roundness (Rnd), ellipticity (Ell). and aspect ratio (Ar), and three characters that do not show significant differences, namely form factor (Ff), circularity (Cir), rectangularity (Rec).
 
 Keywords: Biometrics, cardinal proud fish, comparison
 
 Abstrak
 Penelitian ini bertujuan untuk mengetahui perbandingkan biometrik otolit ikan kardinal banggai berdasarkan jenis kelamin dan mengetahui perbandingan biometrik otolit pada dua lokasi di Perairan Depan TPI Dudepo Kab. Bolaang Mongondow Selatan dan di Selat Lembeh Kota Bitung. Pengambilan data di lapangan menggunakan metode survei jelajah. Penangkapan ikan dilakukan dengan penyelaman snorkling, penangkapan minimal 50 individu yang mewakili setiap kelas ukuran dengan alat tangkap Chang net/Sibu. Perbedaan otolit pada jenis kelamin jantan dan jenis kelamin betina memiliki tujuh perbedaan karakter otolit pada panjang otolit (OL), lebar otolit (OW), area otolit (OA) dan perimeter otolit (OP), roundness (Rnd), ellipticity (Ell) dan aspect ratio (Ar), dan tiga karakter yang tidak menunjukkan perbedaan yang signifikan, yaitu form factor (Ff), circularity (Cir), rectangularity (Rec). Perbedaan otolit berdasarkan lokasi di depan TPI Dudepo dan di Selat Lembeh memiliki tujuh perbedaan karakter otolit pada panjang otolit (OL), lebar otolit (OW), area otolit (OA) dan perimeter otolit (OP), roundness (Rnd), ellipticity (Ell) dan aspect ratio (Ar), dan tiga karakter yang tidak menunjukkan perbedaan yang signifikan, yaitu form factor (Ff), circularity (Cir), rectangularity (Rec).
 
 Kata kunci: Biometrik, ikan banggai kardinal, perbandingan

The relationships between fish size and sagitta otolith measurements were calculated for the first time for 15 species belonging to six families from the northern Brazilian coast. A total of 220 fish were sampled from the bycatch landed by the bottom-trawl industrial shrimp-fishing fleet between August and September 2016. All species had strong relationships between otolith measurements and fish total length with the coefficient of determination (r 2) ranging between 0.71 and 0.99. The variable most strongly related to fish total length was found to be the sagittal otolith length (OL) with 98% of the variability. These relationships are a useful tool to estimate length and mass of preyed fish from otoliths found in stomach contents of marine predators.