Relationships between fish size and otolith size of four bathydemersal fish species from the south eastern Arabian Sea,India

The objective of this study was to estimate a prey body size from the hard parts (e.g. otoliths) of a fish species frequently found in the guts of predators. Length–weight relationships between otolith size (length, height, weight and aspect ratio) and fish size (total length and weight) were determined for four fish species captured in the Arabian Sea by bottom trawl (2015 survey on‐board FORV Sagar Sampada, 200–300 m depth), off the west coast of India: Psenopsis cyanea, Pterygotrigla hemisticta, Bembrops caudimacula and Hoplostethus rubellopterus. No significant differences were noted between the size of the left and right otoliths (t test) in any of the four species. The length–weight relationship of the otolith in all four species showed a negative allometric growth pattern (t test, p < .05). The data fitted well to the regression model for otolith length (OL), otolith height (OH) and otolith weight (OW) to total length (TL) and total weight (TW). Results showed that these relationships are a helpful tool in predicting fish size from the otoliths and in calculating the biomass of these less‐studied fish species during feeding studies and palaentology.     

Biometric relationships between body and otolith measurements in nine demersal fishes from north‐eastern Tasmanian waters,Australia

Relationships between fish and otolith measurements were analyzed in nine demersal fishes from the north‐eastern Tasmanian waters: Foetorepus calauropomus, Trachurus declivis, Parequula melbournensis, Neosebastes scorpaenoides, Platycephalus aurimaculatus, Platycephalus bassensis, Platycephalus conatus, Lepidotrigla mulhalli and Lepidotrigla vanessa. The values of exponent b from the relationships between fish weight and fish total length, total length and otolith length, total length and otolith width, and fish weight and otolith length were estimated. All above relationships were statistically significant. 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. Significant differences in fish length and otolith length relationship between species were highlighted in both gurnards and flatheads. Results from this study will provide novel information on quantitative biometric relationships between body and otolith measurements of fish species in Australian waters.     

Sexual dimorphism in the otolith shape of shi drum,Umbrina cirrosa (L.), in the eastern Mediterranean Sea: Fish size–otolith size relationships

Little is known about possible differences in sagitta otolith size and shape between sexes of the shi drum, Umbrina cirrosa, and relationships between their body and otolith size. Thus, this study aimed to fill this knowledge gap via examination of 414 sagittal otoliths from 108 male (total length 13.8–26.8 cm) and 99 female (13.5–26.7 cm) U. cirrosa caught between May 2017 and April 2018 in gillnets set at a depth of ~15 m in Mersin Bay, Eastern Mediterranean Sea. No statistical differences were observed between the shape indices of the left-sided and right-sided sagitta. However, there were significant differences in the size and shape of otoliths between males and females. The slopes of allometric power functions from otolith width × fish sizes gave significant differences between males and females (ANCOVA, P < 0.05). The relationship for length × weight of otoliths from both males and females showed isometric growth, whereas the relationship of otolith width × otolith weight showed positive allometry. Negative allometric growth was observed for the relationship otolith length × otolith width. In summary, this study revealed the presence of sexual dimorphism in the otolith shape of U. cirrosa, and the data on regression relationships of fish-otolith sizes can be used to estimate fish size from U. cirrosa otolith sizes.     

Length–weight relationships of four fish species from Vembanad-Kole Wetland (Kerala,India)

The length–weight relationships (LWRs) of four fish species were determined from Vembanad-Kole Wetland, Kerala, India between June 2015 and May 2016. Fish samples were collected monthly from various fishing gears such as gill nets (50 m long and 1.5 m height, mesh sizes 30–100 mm, soaking time 8 hr) and seine nets (mesh sizes 8–16 mm). Values of the parameter b ranged from 2.896 to 3.165 and such values are within the expected range. This study reports the new maximum total length for Channa pseudomarulius and Hyporhamphus xanthopterus.     

Length‐weight relationship and GSI index of smallhead hairtail,Eupleurogrammus muticus (Gray, 1831), northern Persian Gulf,Hormozgan coastal waters

Length–weight and length–length relationships (LWR and LLR) and the gonadosomatic index (GSI) were estimated for smallhead hairtail (Eupleurogrammus muticus). A total of 441 fish were collected on a monthly basis from October 2011 to August 2012 using a bottom trawl net at depths of 5–30 m. The length‐weight relationship did not differ significantly between males and females (P > 0.05). Data on the gonadosomatic index (GSI) revealed that spawning is principally from January to June.     

The relationships between fish size and otolith dimensions in the common sole (Solea solea (Linnaeus, 1758)) captured in the Northeastern Mediterranean

Fish specimens were captured by a commercial bottom trawler at a depth of 50–80 m from Iskenderun Bay (Hatay, Turkey) between December 2017 and May 2018. The bottom trawl gear used was equipped with a 44 mm stretched mesh size net at the cod-end. Blind side and eyed side otolith lengths (OL), otolith breadths (OB) and otolith weights (OW) were measured from each specimen to the nearest 0.001 mm and 0.0001g respectively. A total of 110 fish (43 females and 67 males) were collected. Total length ranged from 20.8 to 28.2 cm and 68.0 to 166.1 g (males) and 21.1 to −28.5 cm and 74.5 to 201.4 g (females). The coefficients of determination between fish weight and otolith weight, and total length and otolith weight (sexes combined) were found as R² = .7694 (0.77) and R² = .6274 (0.63), respectively. A moderate positive relationship between the total length-otolith dimensions, and fish weight-otolith dimensions, was also demonstrated.     

Length‐weight relationships of 79 marine fish species from the coastal waters of Hong Kong

Dedicated benthic fisheries‐assessment surveys with beam trawls (2 cm mesh size) were used to sample demersal fish communities at depths 7–35 m along four transects in each of the western, southern and eastern waters of Hong Kong monthly for >24 months. We report length‐weight relationships (LWRs) for 79 species (11 orders, 37 families) of fishes for which LWRs are presently absent or scarce. For 56 of these species, relationships between total length and standard length or disc width were also derived.     

Length–weight and length–length relationships of 20 fish species from the upper Yangtze River,southwest China

Length–weight (LWR) and length–length (LLR) relationships were estimated for 20 species of fish from the upper Yangtze River, southwest China. Samples were collected using multiple types of gear (2–6 cm mesh trammel nets, 2 cm mesh trap nets, and baited hooks) in Jiangjin and Yibin sections from 2007 to 2009. New maximum lengths for 16 species were recorded for FishBase. LWRs were significant for all species. Standard length–total length equations for converting size measurements for these 20 species are also presented. The results provide primary data for future fish research and conservation.     

Relationships between fish and otolith size of nine deep‐sea fishes from the Andaman and Nicobar waters,North Indian Ocean

The study presents for the first time the otolith morphology of nine species of deep‐sea fishes. This study was based on sampling carried out on‐board FORV Sagar Sampada (Cruise No 349) during March‐April 2016, along the continental margin of the Andaman and Nicobar Islands in the Bay of Bengal using high speed demersal trawl. Unbroken (complete) otoliths from Polymixia fusca Kotthaus, 1970, Neoepinnula orientalis (Gilchrist & von Bonde 1924), Chlorophthalmus nigromarginatus (Kamohara, 1953), Cubiceps baxteri (McCulloch, 1923), Bembrops caudimacula (Steindachner, 1876), Neoscopelus microchir (Matsubara, 1943), Ostracoberyx dorygenis Fowler, 1934, Synagrops japonicus (Döderlein, 1883), and Bathyclupea hoskynii Alcock 1891) were used for this study. Length–weight relationships (LWR) and the regression between otolith size (width, weight, area and perimeter) and fish length (TL) of nine deep‐sea Fishes were considered. Numerical relationships derived from the relationship between otolith size and the fish can be used as predictors to estimate the prey size as well as to understand trophic relations and food web dynamics of these hitherto unexamined deep‐sea ichthyofauna. LWR showed negative allometric otolith growth in five species; four species showed positive allometric growth. Otolith size to fish size (TL) relation is explained by a simple linear regression considering otolith width (OW), otolith weight (OWe), otolith area (OA) and otolith perimeter (OP). Stronger r² values (>.76) indicate robustness, except for Cubiceps baxteri (r² = .65), and give better estimates for the TL of the fish.     

Length–weight and length–length relationships of 11 fish species from the Sea of Okhotsk

Estimated length–weight relationships are presented for 11 marine fish species representing six families, found above the continental shelf and in the pelagial of the Okhotsk Sea. A total of 13,841 specimens were caught by trawls that were equipped with a 1.0 by 1.2 cm mesh webbing inset. The period between 1974 and 2015 comprised mostly spring and autumn months. All length–weight relationships were highly significant (r² ≥ .95) on a log scale. None of the species had previous length–weight estimates, and two species had no previous length–length estimates in the FishBase.     

Length–weight relationships for six fish species from the middle of the Yalu Tsangpo River,China

This paper reports the length–weight relationships for six fish species belonging to the Cyprinidae from the middle of the Yalu Tsangpo River in China. Samples were obtained by electroshock and drift net fishing techniques (mesh size 2 cm × 3 cm; 200 m net length) in April and September to October 2014. Length–weight relationships estimates for these species were not available in FishBase. A total of 737 specimens were used to estimate the a and b parameters. New maximum total lengths are also reported for six species. The r² values range from 0.98 to 0.99. Values of b vary from 2.88 to 3.19.     

Morphometric analysis of otoliths of juvenile crucifix sea catfish Sciades proops (Valenciennes, 1840)

The objective of this study was to analyze the morphometry of otoliths for Sciades proops juveniles by testing the hypothesis of equality in morphometric relationships for the right and left otoliths, which could then be interchangeably used to estimate fish size or weight. Samples were obtained monthly directly from anglers after each event that took place off the state of Sergipe from March/2014 to April/2015. Anglers used rod and reel during these events, with no restriction on hook size or line thickness. Each fish specimen sampled had their total weight (W, g) and total length (TL, cm) measured and their lapillus otoliths removed and stored separately. Each otolith had its length (OL), width (OWi), and thickness (OT) measured (all in mm) under a stereomicroscope. Otoliths were weighed using a precision scale (OW, g). A total of 883 specimens were sampled: TL = 12.0–60.5 cm and W = 9.8–1880 g. The weight‐length relationship for the juvenile fishes was W = 0.0052TL^3.086 and for their otoliths was OW = 0.0002OL^3.177. The weight‐length and length‐length relationships fitted for each otolith (right and left) were not statistically different and thus all relations were estimated for grouped otoliths. The length‐length relationships for the otoliths were: OWi = 0.947OL?0.205 and OT = O.484OL?0.698. The relationship estimated for juvenile fish and otolith weight was Wj = 1076.1OW?9.120. For juvenile fish total length and otolith length, width and thickness, the following relationships were estimated: TLj = 4.028OL?3.199, TLj = 4.208OWi?2.091, and TLj = 7.824OT + 3.659, respectively. Relationships between fish and otolith size, and between fish and otolith weight indicated a change in slope close to L_m50, which should be better explored when more adult specimens are available.     

Length–weight relationships of 10 freshwater fish species from an intermittent river basin,semi‐arid region,Brazil

The length–weight relationships for 10 freshwater fish species from an intermittent river basin in a semi‐arid region of Brazil were analyzed. Specimens were caught using a dragnet (3.5 × 2.5; stretched mesh size 5 mm) during running and pool phases from January to November 2015. The specimens were measured for total length and weight. Previously unavailable in FishBase, the detailed length–weight relationships of Compsura heterura, Phenacogaster calverti, and Serrapinnus piaba are reported for the first time. All fish collected presented total lengths (TL) lower than the maximum reported in FishBase.     

Length–weight relationships of five fish species associated with krill fishery in the Atlantic sector of the Southern Ocean

Length–weight relationships (LWRs) of five fish species commonly associated with Antarctic krill fishery, were determined. Samples were collected with Chinese krill trawler (codend mesh size 2 cm) in the Atlantic sector of the Southern Ocean from January to August 2016. Data on LWRs and the relationships between weight and standard length as well as weight and total length of those species were updated for the database of FishBase. Those data on fish species derived from Antarctic krill fishery will be very helpful in understanding the interaction between krill fishery and the associated fish community.     

Length–weight relationships of 43 fish species from Haizhou Bay,central Yellow Sea

Specimens of 43 fish species belonging to 25 families were collected from seasonal bottom trawl surveys in Haizhou Bay from March to December 2011. The length–weight relationships (LWRs) of these fish species were estimated, with 22 species presented for the first time. Maximum total length records of ten species exceeded those in FishBase. The effects of sex, season and growth phase on the relationships for some of these species were taken into account whereby one species had significantly (P < 0.05) different LWRs by sex, and eight species exhibited significantly different LWRs by season. Two different growth stanzas were detected for two species using the double‐logarithmic plot of body weight versus total length.     

Length–weight and length–length relationships of 26 fish species from the Yiluo River,a tributary of the Yellow River,China

From February to October 2016, a total of 9,754 fish specimens were collected from the Yiluo River, a tributary of the Yellow River, China's second longest river. Based on these samples, length–weight relationships (LWRs) and length–length relationships (LLRs) were estimated for 26 species. Among these data, LWRs for 1 species, LLRs for 11 species, and maximum total lengths for six species were not previously recorded in FishBase. The a values of the LWRs varied between 0.0019 and 0.0116, and b values from 2.805 to 3.883. All regressions for LWRs and LLRs were highly significant (p < .001). These results will be useful for sustainable management and conservation of the fish resources in the Yiluo River and the Yellow River ecosystem.     

Length–weight relationships for three fish species from the Yalong River,southwestern China

Length–weight relationships were determined for three fish species: Gymnodiptychus pachycheilus (Herzenstein, 1892), Discogobio yunnanensis (Regan, 1907), and Triplophysa pseudostenura (He, Zhang & Song, 2012). Samples were collected from the Yalong River, southwestern China using fishing gear (gillnets, 30 × 15 m, mesh‐size 5 mm) and electroshock fishing (CWB‐2000 P, 12 V, 250 HZ) in June 2007. Prior to this study, length–weight relationships for these three species were unknown. For two of the species [Discogobio yunnanensis (Regan, 1907) and Triplophysa pseudostenura (He, Zhang & Song, 2012)], new maximum standard lengths not yet reported in the scientific literature were noted.     

Length–weight and length–length relationships of fish species from the Chi River,northeastern Thailand

The relationships of total length (TL), fork length (FL) and standard length (SL) are presented for four fish species and the relationships between TL and wet weight for 23 fish species from the Chi River in northeastern Thailand. All length–length relationships were linear (r² > 0.95). Slope (b) of the length–weight relationships showed values between 2.5073 and 3.4896.     

Length–weight relationships of five fish species from the Hongshui River,China

The length–weight relationships (LWRs) of five Chinese endemic fish species caught by cast nets (mesh size 1 cm) and gillnets (mesh size 4 cm) in the Hongshui River in June and July 2011 and October to November 2012 were determined. These are the first LWRs records for the five little‐known species.     

Length–weight relationships of eight fish species from Guyana coastal drainages,Amapá, Brazil

The present study provides the length–weight relationships (LWR) for eight fish species in 19 streams from the Pedreira River basin, a small tributary of the Guyana coastal drainages from Amapá State, Brazil. Fishes were collected at two occasions, one in November 2016, the other in July 2018, using hand nets, with 0.5 mm of mesh size and 0.25 m² of mouth area, and trawl nets, with 0.5 mm of mesh size and 3 m long. Standard length and total weight were measured to determine the LWRs. The results show that the coefficient b varied between 2.798 and 3.380 and thus the values were within the expected range.