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Deep-water snapper fisheries in the Mariana Archipelago are important commercial, recreational and subsistence fisheries. Pristipomoides zonatus, one of the top four deep-water snapper species harvested in Guam, lacked life-history information. To fill this gap, a comprehensive life-history assessment for P. zonatus, which included age, growth, mortality and reproduction, was conducted in Guam. The size range of P. zonatus sampled for life history was from 11.5 cm to 40.4 cm (fork length), with ages ranging from 0.5 to 30 years. Von Bertalanffy growth model-combined sex parameters were L∞ = 36.91 cm and K = 0.29. Males obtained a larger average size and a larger asymptotic size (+3.03 cm) than did females. Pristipomoides zonatus matures at a small size and age (L50 ≤ 24.0 cm and A50 ≤ 2.1 years) relative to their maximum size (40.4 cm) and age (30 years). Additionally, P. zonatus has a long spawning season and a short spawning interval, suggesting high reproductive output. Our results expand knowledge on Pristipomoides life history (fast early growth, moderately long-lived, high productivity), providing the necessary information for the management of P. zonatus in Guam.

With the lack of information available globally on the reproductive biology of Sphyraena putnamae, the present study was performed using 908 individuals landed along the western Bay of Bengal from January 2017 to December 2019. Fork length of sampled fshes ranged from 17.4 to 123.0 cm in females and 22.2 to 119.0 cm in males, with a mean length of 41.90±0.63 cm and 39.12±0.71 cm, respectively. Growth was negatively allometric with a signifcant (p0.05) during September to October and April to June indicated that these months were the peak spawning periods. Absolute fecundity increased with fork length and weight and varied from 51,507 to 1,063,438 oocytes with an average of 316,205 oocytes. Asynchronous ovarian development with two distinct modes (0.40–0.49 mm and 0.70–0.79 mm) in the oocyte diameter distribution indicated multiple spawning. The present study from the Bay of Bengal provides a comprehensive account of various reproductive attributes, with many being the frst records for the species. The information generated would contribute signifcantly to its stock management in tropical waters.

Age and growth of southern bluefin tuna (SBT, Thunnus maccoyii) were estimated based on otoliths collected by Korean tuna longline vessels in the Atlantic and Indian Oceans from 2015 to 2019. A total of 739 specimens were used to estimate age and growth of SBT, with sizes ranging from 66 to 181 cm in fork length. It was confirmed that the otolith is a suitable aging characteristic for determining SBT age, and otolith annuli can be used as an annual ring. The relationship between fork length (FL) and total weight (W) was W = 7.7e − 05FL2.722 (R2 = 0.874). The von Bertalanffy’s growth parameters estimated from the non-linear method using length-at-age data were L∞ = 170.0 cm, K = 0.200/year, t0 = − 1.615 years, with 95% confidence intervals between 166 and 175 cm for L∞, 0.17–0.23/year for K, and − 2.27 to − 1.09 years for t0 from bootstrapping. The Kimura’s likelihood ratio test results of the models under assumptions of common and different parameters between female and male concluded that the growth of SBT has no difference between genders.

Burst swimming velocity (Uburst) was compared between wild and hatchery-reared chum salmon fry. In the hatchery-reared fry, Uburst was significantly correlated with the condition factor, but not with the body mass and fork length. In the wild-reared fry, on the other hand, Uburst ranged widely and did not correlate with condition factor. These suggest that well-balanced growth under satisfactory nutrient condition at the early developmental stage improves Uburst, and in the wild-reared fry, their cautiousness and various experiences may override the condition factor dependency of Uburst.

This study reports the first data on length–weight (LWR) and length-length (LLR) relationships, and seasonal body condition factors of Blueline snapper, Lutjanus coeruleolineatus (Ruppell, 1838) inhabiting Salalah Coast, Sultanate of Oman. The regression slopes of LWRs were significantly different between immature and mature groups, and among different seasons, but it was not significant between male and female specimens. The relationships between total and standard length, between standard and fork length, and between fork and total length were linear (r2 > 0.972) regardless of sex. The body condition of fish was significantly higher during the southwest monsoon (both pre- and post-monsoon) than during the non-monsoon seasons. The results from this study contribute to understand biology of L. coeruleolineatus and are useful data for the development of conservation and management plans of this species.

Hatcheries and breeding programs use wild-caught fish reared on artificial diets. Understanding how fish adjust to a new feeding environment in this context might contribute to improving survival and growth outcomes under artificial conditions. In this study, we examined the growth and survival of wild white-spotted charr (Salvelinus leucomaenis pluvius) on a diet of commercial pellets in an artificial rearing environment. Our results revealed that pre-study fork length has a significant influence on pellet consumption, and thereby survival. The primary factor contributing to growth was the number of days until an initial increase in body weight. Post-mortem examination of deceased fish and their condition indicated that in all cases, the most likely cause of death was starvation. These results accordingly indicate that starvation tolerance and the ability to adjust to a new feeding environment are key factors in the survival of wild charr, whereas the time taken to acclimate is a key factor contributing to growth.

Two laboratory studies evaluated small Chinook salmon (Oncorhynchus tshawytscha) (36–99 mm fork length (FL), 0.7%–26.7% tag burden) survival, tag retention, and growth (n = 539) and critical swimming speed (Ucrit; n = 241). Fish were implanted with a new active acoustic tag and compared with untagged controls at 12 and 17 °C. Across studies, no temperature differences were detected. All control fish survived. All tagged fish ≥58 mm FL survived and retained their tags. Regression models predicted ≥98.6% survival and retention for tagged fish ≥58.6 mm FL or ≥1.9 g (4.2% tag burden). No growth differences among treatments were identified. Spline regression analysis indicated Ucrit was similar for control and tagged fish that measured ≥57.3 mm FL. We recommend tagging salmon ≥59 mm FL or ≥1.9 g (≤4.2% tag burden), although the guideline should be confirmed in a field setting. Study results represent an important step towards using the new active tag in acoustic telemetry field studies that estimate short-term (30-day) survival of small salmonids.

We estimated the growth of Jack mackerel (Trachurus murphyi) using increments of daily growth, otolith weight and annual ring reading in sagittal otoliths. The daily micro-increments were used to fit ring density to the otolith radius (n = 4481) and then to estimate the age of the individual in days. The parameters of the von Bertalannfy growth equation were: maximum theoretical fork length, FL∞ = 75 cm; individual growth coefficient, K = 0.16 year-1; theoretical age at which fish length is zero, t0= -0.19 years. The growth parameters of T. murphyi estimated using annual rings reading were: K = 0.10 year-1, FL∞ = 74.7 cm, t0 = -0.50 years. The growth parameters estimated using otolith weight were: K = 0.15 year-1, FL∞ = 75.0 cm, t0 = -0.48 years. The parameter K estimated with the daily micro-increments was similar to the K estimated using sagittal otolith weights. We constructed a size-age key for T. murphyi using otolith weight, OW (milligrams) as a variable was: OW= 0.0323*t-15.197 (r2= 0.68). We recommend using otolith weight to estimate age in T. murphyi due to this technique is statistically reliable, but also cheap and fast.

The crocodile shark (Pseudocarcharias kamoharai) is a small lamniform shark that is occasionally by-caught in pelagic longline fisheries targeting tunas and swordfish. Due to its biological features, this species is highly vulnerable to overexploitation. However, at present, the crocodile shark is not evaluated for its stock status by any of the Regional Fisheries Management Organizations. In this study, the biology of 391 specimens (220 females and 171 males), ranging from 44.2 cm to 101.5 cm fork length (FL), collected from the tropical region of the Atlantic Ocean, was examined. Ages were assigned from growth band counts in vertebral sections, with the modified von Bertalanffy growth model, using a fixed size at birth (L0) at 32 cm FL, producing the best fit: Linf = 105.6 cm FL and k = 0.14 y−1 for females; Linf = 94.6 cm FL and k = 0.18 y−1 for males. Maturity ogives were fitted to both length- and age-based data. The size (L50) and age (A50) at 50% maturity was estimated at 67.2 cm FL (5 years) and 81.6 cm FL (8 years) for males and females, respectively. Mean uterine fecundity was 3.7 pups per litter with a 1:1 embryonic sex ratio. Further work is needed regarding crocodile shark life-history characteristics, especially because there are no age validation studies of the band pair deposition periodicity. However, the parameters now presented can contribute to future evaluations of this species, which is especially important given its potentially vulnerable life history.

Concentrations of total mercury (THg) in the axial musculature of northern pike (Esox lucius), walleye (Sander vitreus), lake whitefish (Coregonus clupeaformis), and sauger (Sander canadensis) were analyzed from several regions of Lake Winnipeg and three main inflows, focusing on Mossy Bay in the North Basin of the lake. Length-standardized means (standard means) indicated THg concentrations in pike of 550 mm fork length (0.44 ppm) and walleye measuring 400 mm (0.38 ppm) from Mossy Bay were highest in 1971 and declined to 0.13 and 0.22 ppm, respectively, by 1974. Standard means of both these species have been similar since 2010 (walleye; approximately 0.11 ppm) and 2013 (pike; approximately 0.17 ppm), except for a significant increase to 0.15 ppm in walleye in 2019, potentially related to concurrent changes in trophic interactions with invasive fish and invertebrate species. Standard means of 300 mm long sauger (0.23–0.29 ppm) did not decline significantly between 1971 and 1974, and those of 350 mm long whitefish ranged from 0.006 to 0.028 ppm from 1983 to 2016 with no clear temporal trend. In concert with data from other areas of Lake Winnipeg and the three inflows for 2000–2019, these results indicate higher contemporary concentrations in the South Basin of the lake. This latitudinal gradient in fish THg is assumed to be a result of continuous mercury inputs from the Red and the Winnipeg River, whereas a former point source of industrial mercury in the Saskatchewan River is no longer relevant. According to human consumption limits based on tolerable daily intake calculations and current THg concentrations of fish from Mossy Bay, substantial quantities of whitefish, pike, and walleye fish can be safely eaten.

Liver and skin tumours in brown bullhead (Ameiurus nebulosus) and white sucker (Catostomus commersoni) have been associated with contamination of the aquatic environment. In this study, we present a Bayesian hierarchical logistic-Bernoulli framework that considers the role of fish covariates (e.g., age, total weight, gonad weight, liver weight, fork length) on tumour prevalence to identify the presence of “hot-spots” around the Canadian waters of the Great Lakes, where high fish tumour frequencies are registered. We developed methods to discern the degree of impairment that are either based on the comparison of tumour frequencies in contaminated (or impacted) sites against those predicted in their corresponding reference areas, or the assessment of the prevailing conditions in impaired sites independently, without the need to establish baseline conditions for comparison purposes. Our modelling study predicts low frequencies of neoplastic tumours in all the impacted locations. In contrast, the same comparisons with the preneoplastic lesions provided evidence of distinct differences between impacted and reference sites in Jackfish Bay, St. Mary’s River, Niagara River, Hamilton Harbour, and Bay of Quinte. We also found weak to moderately strong relationships between tumour occurrence and fish physical characteristics that varied considerably in terms of their strength and nature (sign) among the different locations. Our study concludes that the prevalence of neoplastic tumours appears to have reached acceptable levels around the Great Lakes, but the distinctly higher levels of preneoplasms in several impacted locations underscore the need to improve our understanding of the lesions that may lead to carcinogenesis.

The aim of the current study was to determine the length-weight relationship (LWR) and length-length relationship (LLR) with condition factor (K) values for Oxynoemacheilus angorae from the Perşembe Plateau meandering streams in Ordu, Turkey. A total of 65 fish specimens, which were caught with electrofishing gear, were examined. Fish standard length (SL), fork length (FL), total length (TL), and body weight (W) were determined. There were no statistical differences between the measurements of male and female O. angorae specimens; therefore, the female and male specimens were evaluated together in the current study. The LWR equation and determination coefficient of O. angorae were W = 0.014 TL2.7359 (r2 = 0.9659). The 95% confidence interval of the b value for the O. angorae specimens from the Perşembe Plateau meandering streams was 2.7261 to 2.7435. In the present study, it was determined that O. angorae specimens showed negative allometric growth. Calculations of O. angorae TL-SL, TL-FL, and FL-SL relationship equations and determination coefficients were as follows: TL = 0.2091+1.1646 SL, (r2 = 0.986); TL = 0.1341+1.0301 FL (r2 = 0.9914); and FL = 0.0998+1.1261 SL, (r2 = 0.9868), respectively. A new maximum total length was recorded for O. angorae in this study. The average condition factor value of O. angorae was 0.9954. This value could have indicated that this species was encountering some problems in this habitat. The O. angorae parameters determined were the first data reported for the Perşembe Plateau meandering streams in Ordu, Turkey (Middle Black Sea Region).

The invasive rainbow smelt (Osmerus mordax) was an abundant food source for Lake Winnipeg walleye (Sander vitreus), especially in the north basin of the lake, until the smelt’s collapse in approximately 2013. We quantified changing length-at-age (≈ growth rates) and relative mass (≈ body condition) in Lake Winnipeg walleye caught for a gillnet index data set. Here, walleye showed smaller length-at-age, particularly young fish in the north basin, over time. This approach to assessing growth suggests a constraint in the north basin fish, possibly a nutritional limitation between 2017 and 2018, that was not present in the south. We then analyzed a separate group of walleye (≥452 mm in fork length) sampled in 2017 as part of a large-scale tracking study, which had a similar slope in length-mass relationship to large walleye caught in that year for the gillnet index data. A panel of metabolites in whole blood samples associated with amino acid metabolism and protein turnover was compared. These metabolites revealed elevated essential amino acids in fish caught in the Dauphin River, and suggest that protein degradation may be elevated in north basin walleye. Therefore, based on both growth estimates and metabolites associated with protein balance, we suggest there were spatially distinct separations affecting Lake Winnipeg walleye with decreased nutritional status of walleye in the north basin of Lake Winnipeg being of particular concern.

In the last decades, high concentrations of flame retardants (PBDE) in marine organisms have caused increasing concern among scientists with regards to their biomagnification potential and to human health. Poly-Brominated Diphenyl Ethers have been widely used in the past as flame retardants in various industrial sectors, and their presence in the biota has been associated with different toxicological effects. In this study, concentrations of 9 congeners of PBDE (183, 85, 153, 154, 99, 100, 47, 66 and 28) and morphometric parameters (Total Length, TL; Fork Length, FL in cm and weight) have been measured in muscle of males and females of Atlantic herring (Clupea harengus). Results showed no statistical differences between the concentrations of most of the congeners analysed between the two sexes, except for PBDE 153 (Mean ± standard error in males = 0.034 ± 0.005 μg/kg and in females = 0.086 ± 0.040 μg/kg; p = 0.003). This research contributes to better comprehend the ecotoxicological properties of these molecules and their implications for human consumption.

More than 1000 thermal and mineral water springs with temperatures from 20°C to102°C occur in Turkey. Kangal Balikli Hot Spring is known as psoriasis treatment center is one of the most important among these springs. The main scope of this research was to determine geological, hydrogeological and biological properties and water chemistry of the psoriasis treatment center and the stream running alongside the thermal pools. The spring water is an isothermal-hypotonic and oligometalic mineral water, having average of electrical conductivity: 530 μS cm-1, temperature: 35°C, CO2 8.70 mg l-1, pH 7.30 and O2 4 mg l-1. Calcium, magnesium and bicarbonates are dominant. Neither the chemical figures nor the temperature (35±1°C) of the water shows seasonal change. There are two fish species, Garra rufa and Cyprinion macrostomus, that adapted living at 35°C water temperature. The mean fork length and body weight of the fish living in the psoriasis treatment center is significantly lower than those living at the stream. Some of the fish in the pools showed symptoms of illness such as exophthalmus, scale loose, skin ulceration, pale gills, and bloated appearance. Gut analysis revealed that both species have been feeding on algae, insect parts, fish scales, and debris. In most cases the guts of fish caught in the pools were either empty or had very little content in it. Zooplanktons had little species and were not recorded frequently.

Length–length and length–weight relationships in various length measurement standards were estimated for dominant small pelagic fishes in the Kuroshio–Oyashio current system (Japanese sardine Sardinops melanostictus, Japanese anchovy Engraulis japonicus, chub mackerel Scomber japonicus, and spotted mackerel Scomber australasicus). Fish samples were collected from surface–midwater trawl surveys and commercial purse-seine fisheries between September and October of 2020 in the western North Pacific. Total length (TL), fork length (FL), and standard length (SL) were measured to 0.01 cm, and total body weight (W) was measured to the nearest 0.01 g for each individual. All length–length relationships (TL–FL, TL–SL, and FL–SL) were highly significant (p 0.98 in all species. Length–weight relationships (W–TL, W–FL, and W–SL) were also highly significant (p 0.98 in all species. This study provides new comprehensive information on length–length and length–weight relationships in various length measurement standards for the four small pelagic fish species. These data will be useful references for biological studies and stock assessments of these small pelagic fishes.

We studied life‐history traits focusing on the growth and condition of the pikeperch Sander lucioperca to evaluate its phenotypic plasticity when introduced to new environments. Pikeperch is a non‐native fish introduced to Iberian freshwater fauna in 1998 that quickly spread to other river basins through human‐mediated activities, occupying now a wide variety of habitats along mainland Portugal. Condition (K and SMI), fork length at age, and length–weight relationships were studied for Portuguese populations. Pikeperch fork length for ages 1, 2, 3, and 4 was different between several populations. We applied generalized linear models (GLM) to study the influence of habitat type, latitude, altitude, time after first detection, and fish prey richness on pikeperch populations size at age 4 and condition. We observed higher condition values on populations from lower altitudes at lentic systems more recently introduced. But higher fork length at age 4 was found in populations from higher altitudes, on older populations with higher prey richness. Habitat type, time since first detection, and fish fauna composition are discussed as the main environmental factors explaining the observed phenotypic plasticity with concerns on predatory impact on native fauna., Sander lucioperca is a non‐native fish which colonized a variety of Portuguese freshwaters and showed adaptive phenotypic plasticity on condition and growth to such new environments. Habitat type, time since first detection, and fish fauna composition are discussed as the main environmental factors explaining the observed phenotypic plasticity with concerns on predatory impact on native fauna.

Morphometric and meristic characters are very important for the identification of any fish specimen. The present study aims to describe the morphometric and meristic characters of the indigenous fish Crossocheilus diplochilus (Heckel) from Dal Lake. This fish is commonly known as Kashmir latia and is called tether locally. In the present study, the material analyzed was 70 specimens ranging in size from 6.9–13 cm (TL) with a mean length of 10.8 cm and a weight range of 3.2–24.0 g with a mean weight of 10.1 g. The parameters with the highest correlations with total length were standard length and fork length at 0.983 and 0.989, respectively. Correlation analysis showed that all morphometric characters changed proportionally as total length increased. The meristic counts analyzed in the present study remained constant in fish of different sizes indicating that they are independent of body size. The study of morphometric characters is very important to determine the growth rate of these fish, which, in turn, is required to properly manage its populations.

Age, growth, and reproductive traits of two large emperor fishes Lethrinus olivaceus (n = 144, 26.9–76.8 cm fork length) and L. xanthochilus (n = 127, 24.2–64.8 cm) were investigated in the Yaeyama Islands (24°N, 124°E), Okinawa, southern Japan. Spawning was confirmed from April to June for L. olivaceus and April to May for L. xanthochilus. Otolith opaque zones in both species were found to be formed during spawning season and to be annual marks. Maximum observed ages were 22 years old for L. olivaceus and 17 years old for L. xanthochilus. Estimated von Bertalanffy growth parameters were L∞ = 71.9 cm, k = 0.258 year− 1, t0 = − 0.613 years for L. olivaceus and L∞ = 62.5 cm, k = 0.175 year− 1, t0 = − 2.157 years for L. xanthochilus. Hermaphrodite gonads were observed in adult size of L. olivaceus and immature size of L. xanthochilus. However, dominance of females in young age classes (L. olivaceus: 1–8 years old; L. xanthochilus: 1–4 years) and of males in older age classes (L. olivaceus: >9 years old; L. xanthochilus: >5 years) implied that both species are basically functional protogynous hermaphrodite. Relatively long lives and functional protogyny, which leads to low abundance of males, indicate that both species are vulnerable to fishing pressure.

The accurate estimates of the maximum length of fish within a population are significant issues. Because the parameters related to maximum length, weight and age of fish communities in the ecosystem are constantly used in population dynamics and stock estimation studies, recording of such data is vital for determining the life history of fish. In this connection, a single specimen of Scomber japonicus was captured off Kabatepe Bight (Gallipoli Peninsula) with handline by a commercial fisherman on 21 September 2013. This specimen was 370.00 g in total weight and 34.6 cm in total length (32.0 cm in fork length), corresponding to the second maximum size recorded for Turkish waters. This study aims to contribute to the scientific literature.

Schizothorax labiatus (McClelland) is considered to be one of the most economically important fish species among Schizothorax spp. A total of twenty-four morphometric and five meristic characters were examined; 18 of the morphometric characters as percentages of total length and four characters as percentages of head length were studied. It was found that the characters of standard length, fork length, pre pelvic length, pre anal length, and pre dorsal length had the highest correlations with total length, whereas dorsal fin height followed by caudal fin height had the lowest correlations. In percentages of head length post orbital length had the highest correlation whereas snout length had the lowest correlation. Overall, the results revealed that all the morphometric characters exhibited linear relationships and depicted significantly (P < 0.05) high degree of correlation, while the meristic characters counted were constant in all sizes of S. labiatus, indicating that they were independent of body size. The study provided basic information that will be useful for fish biologists and researchers in the future management and conservation of this fish species.

The fish monitoring effort has been increasing over the past years, due to conservation and management requests demanding more accurate data and consequently raising costs. This is an important challenge especially for remote and disperse locations where fish sampling poses unbearable costs, leading to limited spatial sampling schemes, limited data on rare and occasional landed species, and erroneous and biased observations. In this article, we propose a new autonomous system that can be installed on monitoring spots or on board fishing vessels, which is able to remotely acquire all the landed or captured fish and measure it automatically without any physical interaction. The system uses (i) a camera and a 3D sensor to obtain a complete XYZ reading of the fish and (ii) a convolutional neural network, trained for a representative set of species to detect and measure the individuals visible in a box. The system was validated in real conditions, using continuous observations of the landed fish in three islands of the Azores Archipelago, for 2 years. The aim of this article is to provide an overview of the measuring system and an analysis of the sampled data, by comparing the results of the proposed method with the traditional sampling methodology for a given period.

International audience; Tunas are among the most traded and valued fish species, and good traceability of tuna products in the world market is needed to protect both consumers and tuna stocks. To that purpose, high-resolution proton nuclear magnetic resonance (1H NMR) spectroscopy combined with multivariate data analysis was used to investigate the molecular components of the aqueous extract of white and red muscles in three species of wild tropical tuna species, namely yellowfin tuna (Thunnus albacares), skipjack tuna (Katsuwonus pelamis) and bigeye tuna (T. obesus). Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) applied to the processed 1H NMR spectra showed significant separation according to the species and size category (i.e., small tunas < 80 cm fork length vs large tunas > 80 cm fork length), the storage conditions on-board the purse-seine vessels (i.e., brine- vs deep-freezing), and the geographical origin (i.e., where the tuna was caught: Mozambique Channel vs western-central Indian Ocean). The major groups of metabolites responsible for differentiation in PLS-DA score plots were the dipeptides (anserine, carnosine) and organic acids (lactate, creatine/phosphocreatine) in the white muscle, and the free amino acids, essential nutrients (choline and its derivatives, phosphatidylethanolamine), dipeptides and organic acids in the red muscle. Our results showed that NMR-based metabolomics is a powerful tool to efficiently discriminate specific profiles among wild tuna species, raw muscle tissues, fish storage conditions and tuna geographical origin.

This study presents age-based life history information on three small-bodied species targeted in the American Samoan fishery: Chlorurus japanensis palecheek parrotfish/fuga-alosama, Lethrinus rubrioperculatus spotcheek emperor/fiola pa`o`omumu, and Naso lituratus orangespine unicornfish/ili`ilia. Age and reproductive information were derived from sagittal otoliths and gonads. Maximum observed ages were 7 years for C. japanensis, 10 years for L. rubrioperculatus, and 25 years for N. lituratus. Due to a limited numbers of immature samples, a proxy for size at 50% maturity (L50) was derived from the relationship between asymptotic fork length (L∞) and L50 based on data published for species from similar geographic regions and respective families. L50 was estimated at 20.9 cm for C. japanensis, 20.4 cm for L. rubrioperculatus, and 17.5 cm for N. lituratus. Derived estimates were within 1 % of the L50 calculated for C. japanensis and N. lituratus from the limited number of immature samples collected in this study, indicating that for regions where sampling ability is limited, derived relationships between L∞ and L50 can be used to calculate an appropriate proxy. Naso lituratus demonstrated a biphasic mortality schedule with a higher than expected total mortality rate in the first 7 years of life. The age-based demographic information presented here can be used for future stock assessments and ecosystem models, which should facilitate improved management.

The distribution and early growth of juvenile Pacific bluefin tuna (PBF) Thunnus orientalis were studied based on trawl surveys conducted around Sado Island, eastern Sea of Japan, from late August to early September in 2017 and 2018. Juvenile PBF were mainly collected in an area between the Tsushima Warm Current and land where the surface water (5-m depth) temperature ranged from 22.8 to 27.2 °C. The fork length (FL) of the fish ranged from 12 to 320 mm, and there were modes at 140–170 mm FL in the frequency distribution for both years. In 2018, there was also a mode at around 50 mm FL. Otolith microstructure analysis revealed that hatch date mainly peaked in early and mid July in both years, and in early and mid August in 2018, and corresponded with the modes of FL. In addition, differences in growth were observed between year classes, and between size classes in 2018. Total gill raker number increased with FL and was almost constant at around 100 mm FL. This study provides an update of the distribution of juvenile PBF in the Sea of Japan, which was found to be related to the Tsushima Warm Current, and indicates the importance of the eastern Sea of Japan as a nursery ground for PBF that hatch from July to August.

To manage health conditions of farmed fish and other living creatures, a simple method to measure bioelectric signals of the creatures in seawater is expected. A novel method to measure bioelectric signals by utilizing the conductivity of seawater surrounding the entire body of a fish is proposed. As for the proposed method, a needle-type internal electrode is inserted into the fish’s muscle at a certain measurement point, and an external electrode is sunk in seawater. The internal electrode is isolated from the seawater by virtue of being inserted in the fish. Bioelectric signals generated between the external and internal electrodes are then measured. By sharing the external electrode with the internal electrode, it is possible to measure bioelectric signals with half the number of bioelectrodes used by conventional methods. To demonstrate the practicality of the proposed method, two internal electrodes were inserted into different parts (above the gills and near the tail) of three fish (Parajulis poecilepterus, ca. 20 cm fork length) kept in a tank. The proposed method obtained reliable bioelectric signals corresponding to electrocardiograms (ECGs) and electromyograms (EMGs) from each part of the individual fish.

The effect of incubation and rearing temperature on muscle development and swimming endurance under a high-intensity swimming test was investigated in juvenile Chinook salmon (Oncorhynchus tshawytscha) in a hatchery experiment. After controlling for the effects of fork length (LF ) and parental identity, times to fatigue of fish were higher when fish were incubated or reared at warmer temperatures. Significant differences among combinations of pre- and post-emergence temperatures conformed to 15-15°C > 15-9°C > 9-9°C > 7-9°C > 7-7°C in 2011 when swimming tests were conducted at 300 accumulated temperature units post-emergence and 15-9°C > (7-9°C = 7-7°C) in 2012 when swimming tests were conducted at an LF of c. 40 mm. The combination of pre- and post-emergence temperatures also affected the number and size of muscle fibres, with differences among temperature treatments in mean fibre cross-sectional area persisting after controlling for LF and parental effects. Nonetheless, neither fibre number nor fibre size accounted for significant variation in swimming endurance. Thus, thermal carryover effects on swimming endurance were not mediated by thermal imprinting of muscle structure. This is the first study to test how temperature, body size and muscle structure interact to affect swimming endurance during early development in salmon.

Neolissochilus hexagonolepis (McClelland, 1839) is one among the notable species in snow-fed torrential rivers of Nepal. The present study attempts to investigate some reproductive traits of N. hexagonolepis, including the length at first maturity, fecundity and its relationships with biometric variables like lengths (TL, SL, and FL) and weights (TW and OW) of the fish in the mid-reaches of Tamor River, Nepal. A total of 109 fish samples were collected from the river. For each individual, total length (TL), standard length (SL) and fork length (FL) were measured in a fully stretched condition to the nearest 1mm using a measuring tape and graduated ruler, while total weight (TW) and ovary weight (OW) was measured using a digital balance with the precision of 0.01 g. The mean absolute fecundity (F) was 8356.44 ± 4612.59 and ranged from 2398.6 to 20160. SL was more significantly correlated with absolute fecundity (R2=0.59; p

We examined the sea-entry conditions (i.e., timing and body size) of juvenile chum salmon that improve their survival during their coastal residency. On 25 June 2013, we sampled 365 juvenile chum salmon [57.5–98.6 mm fork length (FL)] off Konbumori, eastern Hokkaido, ⁓ 20 km east of the Kushiro River mouth, which originated from a hatchery in the Kushiro River. Sea-entry conditions of these Konbumori juveniles back-calculated using otolith daily increment analysis were compared with data from 373 juveniles released from the same hatchery that were captured at the mouth of Kushiro River (i.e., just before sea entry) from April to July 2013. Most of the Konbumori fish were estimated to have entered the sea from 25 May to 5 June, when coastal surface temperatures constantly exceeded 5 °C, which is considered favorable for juveniles. The estimated FLs at sea entry of the Konbumori fish were larger than FLs of fish sampled at the river mouth during a comparable period, which suggests that size-selective mortality existed. Back-calculated post-sea-entry growth rates of fish with larger FL at sea entry, particularly those with FL > 65 mm, tended to be high enough for survival among the Konbumori fish. Assuming growth-dependent mortality, this case study suggests that the release of larger-sized juveniles under favorable coastal temperature conditions improves their survival.

The reproductive biology of a commercially important sparid, the goldlined seabream Rhabdosargus sarba, was determined from examination of 802 specimens (443 females, 232 males, 68 fish of undifferentiated sex, and 59 bisexual fish) collected by fisheries operating in the central waters of the Taiwan Strait (henceforth “central Taiwan Strait”) from January to December 2016. Previous studies undertaken in other parts of the world have yielded conflicting information on the reproductive biology of this species. Based on macroscopic appearance, the gonadosomatic index, and histological examination of the gonad tissues, the spawning season of this species in the central Taiwan Strait was determined to be from December to March. R. sarba is an asynchronous spawner, with a mean estimated fecundity of 825,078 ± 431,672 eggs. The sex ratio, 0.66, was significantly different from 0.5, and females predominated in most size classes and monthly samples. Size at 50% maturity was estimated to be 23.7 and 20.9 cm fork length for females and males, respectively. Ovotestes were identified in both young and adult individuals, which suggests that R. sarba is a rudimentary hermaphrodite in the central Taiwan Strait. This finding is similar to that for conspecifics reported from Australia, but differs from those reported for other geographical regions. Monthly variation in the condition factor and in the hepatosomatic index indicated that the energy reserves of the muscles and liver may be closely linked to the spawning activity of this species.

The fork length of the specimens of C. hippurus collected along Karnataka coast ranged from 30- 123 cm and fishes having length range from 33-73 cm represented 79% of the total fish sampled. The estimated b values of C. hippurus for both males and females were less than 3 which indicated negative allometric growth; the fish grows faster in length than weight. The most dominant item recorded in the gut of C. hippurus was pelagic and mesopelagic teleosts. Cephalopods (squids, cuttlefish and octopus) were the second important food constituent while crustaceans consisting of crabs and shrimps formed very less quantity.

The present study was carried out to established the relationship of total length and total weight, the relationship of total length (TL), standard length (SL), and fork length (FL) and also condition factor of native fish species Labeo bata from Kolong River of central Brahmaputra valley of Assam. A total of 334 specimens were collected for this present study from May 2018 to April 2019. The length-weight relationship (LWR) was calculated separately with male, female, and pooled data and growth was shown negative allometric (b

The morphometric analysis was carried out in indigenous cyprinid food fish, Schizothorax labiatus (a species of snow trout) collected from Vishav stream, a perennial cold water stream of Kashmir valley, India, wherein various morphometric characters viz., Total Length (TL), Standard Length (SL), Fork Length (FL), Pre-dorsal Length (PDL), Pre-pectoral Length (PPL), Pre-pelvic Length (PPeL), Pre-anal Length (PAL), Anal Fin Length (AL), Head Length (HL), Height of Dorsal Fin (HOD), Snout Length (SnL), Body Depth (BD), Eye Diameter (ED), Inter Orbital Length (IOL), Caudal Fin Length (CL) and Caudal Depth (CD) of 104 fish specimens were measured, correlated and analysed. The morphometric data was calculated in the percentage of total length except SnL, ED and IOL which were calculated in the percentage of HL. The result revealed that the correlation coefficient ranged from 0.770 to 0.995 in proportion to TL and 0.706 to 0.859 in proportion to HL which indicates that all the morphometric characters are highly correlated. All the correlations were significant at the level of p

Mini purse seine has a major contribution in increasing production of small pelagic catches in Pelabuhan Perikanan Pantai (PPP) Muncar, because it has high productivity and the construction made according to catch schooling fish. This research aims to compare the catches composition and catch rate of mini one-boat and two-boat purse seine in Bali Strait, Indonesia. This research was conducted in Mei 2018 in Muncar, East Java, Indonesia. The method used in this research is survey. The primary data are total catch composition, fork length, individual weight of total catch and operation time of both fishing gears. Data were analysed by main catch and bycatch proportion, legal size proportion and catch rate. The results showed that the mini two-boat purse seine had a greater catch volume compared to the mini one-boat purse seine. The bycatch composition dominates in both fishing gear. The proportion of legal-size catching is 67% of the total. The fork length is not significantly different and for the total catches is significantly different. The catching rate of the mini purse seine one boat catch rate is lower at 4,048.67 kg/hour, compared to the mini two-boat purse seine which is 9,189.18 kg/hour.

Biometric indices of Pomadasys jubelini from Obuama Creek, Rivers state, Nigeria were investigated using length frequency distributions (LFDs), length-weight relationships (LWRs), length-length relationships (LLRs), condition factors (allometric, K A , Fulton’s, K F and relative, K R ). Specimens were captured in a stretch of the creek from March to September 2019. A total of 229 specimens were examined with the total length (TL) and weight (W) ranging from 8.7 to 50.4 cm and 8.7 to 834.5 g respectively. The standard length (SL) ranged from 5.3 to 46.8 cm, fork length (FL) was between 6.5 to 48.7 cm and the girth length (GL) varied from 4.7 to 38.7 cm. The relationships of weight-length showed a negative allometric growth pattern with a value of "b" of 2,666. Fulton's condition factor (K F ) ranged from 0.10 to 5.45, with an average of 1.21±0.66 indicating perfect wellbeing for the species. The LLR's allometric coefficient ' b ' between TL vs. FL and TL vs. GL showed positive allometric growth, while SL vs. FL, SL vs. TL, SL vs. GL, and GL vs. TL showed negative allometric growth, although the values were close to 1. These findings also provided some new and updated information on some of the morphometric characters of Pomadasys jubelini in Obuama Creek that could be useful for fisheries management and fish species protection measures in the creek and adjacent habitats.

Reproductive traits and natural mortality rate of cardinalfish females (Epigonus crassicaudus) were studied from samples collected onboard commercial fishing vessels, from 2012 to 2015, on the Chilean coast. The reproductive cycles of females analyzed thought gonadosomatic index (GSI) showed a maximum reproductive activity in austral fall, between March and May. Length (L50%) and age (A50%) at maturity, estimated using a macroscopic scale of the developed ovary, was 22.3 cm fork length (FL) and 9.3 years, respectively. Natural mortality (M) was estimated by two age-related methods. Using maximum age (tmax) M was estimated in 0.063 yr-1 and through age-at-maturity (A50%) in 0.15 yr-1. A potential bias in the reproductive study is discussed when a macroscopic maturity scale is used. Nevertheless, its usefulness is validated when funding is scarce, and time is limited. Although M uncertainty was not evaluated, the estimated range appears to be into the expected values to long-lived species. The life history parameters estimated in the present study can be used to evaluate possible time variability in maturity and M rates. Also, these results could be used in stock assessment analysis and to apply effective management measures in the fishery.

Steelhead trout (Oncorhynchus mykiss) reared at the Nimbus Fish Hatchery (NFH) and released into the Lower American River (LAR) in California are not part of the native California Central Valley Distinct Population Segment (CCVDPS); listed as threatened under the Endangered Species Act (ESA), and therefore cannot contribute to recovery. In response to this situation, we evaluated the potential of using a CCVDPS stock from the Coleman National Fish Hatchery (CNFH) to aid in recovery. Steelhead from the CNFH were reared in 2015 at NFH along with NFH-origin steelhead. Smolts from both stocks were implanted with acoustic transmitters and released into the LAR. This study assessed: 1) reach-specific, post-release survival of each stock from release to the ocean; 2) the degree to which either stock residualized; and 3) the spatial distribution of post-release mortality in the LAR. Multistate mark-recapture models were constructed to estimate reach-specific survival and entrainment into alternate migration routes. Four models were constructed to test hypothesized relationships between survival and covariates. Covariates included: 1) broodstock origin; 2) release date; 3) fork length; and 4) no covariates. Fork length was the best predictor of reach-specific survival and exhibited a positive relationship with survival in each reach. Juveniles from both stocks emigrated quickly, did not residualize, and exhibited similar survival while emigrating to the ocean. Results suggested the need for additional research to further evaluate CNFH-origin steelhead performance at NFH-origin during additional life stages to support recovery of CCVDPS Steelhead.

Ectoparasitic flatworms of Nasicola (Monogenoidea: Capsalidae), which infect nasal epithelium of true tunas (Thunnus spp.), are not well studied, nor have their impacts on the host's olfactory organ been evaluated. Infections of Nasicola hogansi on Atlantic bluefin tuna, Thunnus thynnus, were investigated with emphasis on the relationship between infection prevalence, abundance and mean intensity with bluefin tuna size, sex, body condition and capture month, as well as histopathological effects. Commercially caught Atlantic bluefin tuna (n = 161, 185-305 cm curved fork length) from the Gulf of Maine were sampled during June through August 2009 for infections by N. hogansi. A total of 247 specimens of N. hogansi were collected, with a prevalence of 45.3%, mean abundance of 1.57 (CI: 1.21-2.03) and mean intensity of 3.45 (CI: 2.91-4.22). Neither fish sex nor landing month had a significant effect on parasite parameters. Larger and better-conditioned Atlantic bluefin tuna had a higher mean intensity of infection. Pathology associated with infection by N. hogansi included extensive necrosis, sloughing of the nasal epithelium and associated inflammation of underlying connective tissues. Further epidemiological and pathological study of this host-parasite system is warranted since impaired olfaction, if present, could adversely affect spawning and migration of this top ocean predator.

This study described about the morphometric characteristics of Botia lohachata, collected from the Kompo River at Rajshahi , were studied for a period of four months from July to October 2014. Length frequency distributions, length-length relationships, length-weight relationship, sex ratio, Fulton's condition factor and fecundity of B. lohachata were studied in the present study. This is the maiden research conducted on B. lohachata in Bangladesh. The highest mean total lengths were 61.16±4.77 mm (combined sex), 63.80±4.79mm (female) and 58.17 ±3.30mm (male). Maximum 43.34% female fishes were belonging to the length category of 61-65 mm where as 61.41% male were belonging to 56-60 mm. Similar findings are also presented for standard length, fork length, body depth, dorsal length, pectoral length, pelvic length and anal length. Linear relationships were also studied among mentioned lengths. Strong positive correlations were observed in all cases. The highest mean body weight was weight 2.67±0.71g (October) in combined sex, this value was 3.10±0.59 in female (September) and 2.25±0.38g in male (September). Strong positive correlations were also observed between total length and body weight. Observed value of sex indicated that 54% specimens were female and remaining 46% were male. The value of chi square (x2) was 2.4 at 1 degree of freedom (p

Ikan tenggiri Papua (Scomberomorus multiradiatus) adalah ikan endemik Papua yang tertangkap hanya di sekitar perairan Merauke. Pemanfaatan ikan ini oleh masyarakat lokal dengan tingkat produksi mengalami peningkatan dari tahun ke tahun. Dalam pengelolaan populasi ikan tenggiri Papua diperlukan kajian ilmiah tentang aspek biologi dan pemanfaatannya dengan menggunakan jaring insang hanyut. Penelitian dilakukan selama 2 (dua) tahun yaitu Maret - Desember 2017 dan April -Desember 2018 dengan metode survei yang dibantu oleh enumerator secara bulanan. Data komposisi hasil tangkapan jaring insang hanyut dominan ikan demersal karena dioperasikan di perairan dangkal yang menyapu hingga ke dasar. Ikan tenggiri Papua hanya sekitar 6-10% dari total tangkapan dengan struktur ukuran dominan pada 40 cmFL (fork length) dan pola pertumbuhan allometrik positif. Nisbah kelamin ikan tidak seimbang dengan dominan jantan dibandingkan betina. Ukuran ikan yang pertama kali tertangkap semakin kecil ukurannya yaitu 32.08 (2017) menjadi 30.50 (2018) yang dapat menjadi indikasi bahwa ukuran ikan semakin kecil. Laju pertumbuhan (K) sekitar 0.64 yang menunjukkan laju pertumbuhan tergolong lambat dengan laju kematian akibat penangkapan (F) lebih tinggi dibandingkan kematian alamiah (M). Pemanfaatan ikan ini sudah mencapai E=0,70 atau 140% sehingga harus dilakukan pengurangan 40% dari upaya saat ini dan dengan mengembangkan kearifan lokal agar ikan endemik terjaga populasinya.

Common carp (Cyprinus carpio) is one of the most important cultured fish in the world aquaculture industry. The aim of this study was to determine the phenotypic parameters of some body measurements in common carp (Cyprinus carpio L., 1758) reared in pools in Kirkuk province of Iraq. In this study, the means of body weight (BW), total length (TL), body depth (BD) and fork length (FL) in common carps were determined as, 2.097±0.034, 45.820±0.242, 14.446±0.240 and 38.040±0.210 for male and 2.050±0.033, 45.850±0.277, 14.120±0.154 and 37.960±0.227 for female (P>0.05), respectively. Besides, condition factor (K) was determined as 2.1829±0.0338 for male and 2.1383±0.0409 for females (P>0.05), respectively.

Ovarian maturation, size at sexual maturity and the annual reproductive cycle of female crimson sea bream Evynnis tumifrons were studied using samples collected from April 2012 to June 2014 off the southwestern coast of Kyushu, Japan. A total of 801 ovaries were examined histologically to estimate the degree of ovarian maturation. E. tumifrons showed an asynchronous ovary signifying multiple spawning in a single reproductive season. Ovarian maturity stages were classified into six categories based on the appearance of the most advanced oocytes, post-ovulatory follicles and atretic oocytes in the ovary as follows: immature, maturing, mature, spawned, spent and resting. Females with ovaries at maturing, mature, spawned or spent stages were defined as sexually mature individuals, and the size at sexual maturity was estimated to be 179-mm fork length based on 50% maturity size. Monthly changes in the gonadosomatic index and the occurrence of mature or spawned maturity stages showed that the spawning season lasts from November to May with an intermission in March 2013. The factor responsible for this intermission was considered to be the low water temperature that occurred in the preceding month.

Simple Summary The Atlantic bluefin tuna Thunnus thynnus is a species characterized by complex trans-oceanic migrations linked to size, which rely on the delicate trade-off between somatic growth and reproduction before and during the migratory movements to reach spawning grounds. Therefore, understanding the processes that drive reproduction and elucidating its age-related regulation is essential in the context of sustainable fishery management. In this study, carried out in the Mediterranean Sea, older bluefin tuna females were found to have greater reproductive performances than younger females according to a molecular biology approach (i.e., gene expression), a result that likely mirrors a better physical condition, different habitat usage or migratory behaviour. This result highlights the importance of preserving large females for their major reproductive contribution at a stock level. Furthermore, the gonad-specific mir-202, which belongs to a class of non-coding RNA, called miRNA, that regulate the post-transcription of protein-coding genes, was identified as a potential candidate to play a role in egg quality and quantity (i.e., fecundity) during ovarian maturation through age- or stage-dependent reproductive processes. Overall, the present study contributes to improve the sustainability of the Atlantic bluefin tuna fishery in the Mediterranean Sea. Abstract In the Mediterranean Sea, a demographic substructure of the Atlantic bluefin tuna Thunnus thynnus has emerged over the last decade, with old and young individuals exhibiting different horizontal movements and spatial–temporal patterns of gonad maturation. In the present study, histology and molecular reproductive markers were integrated with the gonad-specific mir-202 gene expression and ovarian localization to provide a comprehensive picture of the reproductive performances in young and old females and investigate the role played by the mir-202 during gonadal maturation. During the reproductive period, old females (>100 kg; 194.6 ± 33.9 cm straight fork length; 11.3 ± 2.7 years old) were found to have greater reproductive performances than younger females (

Inland fisheries are important socio-economic resources for rural communities in Africa. In Rwanda, about two million people directly depend on capture fisheries from Lake Kivu. Sustainable fisheries management requires monitoring of population dynamics that help devise effective intervention strategies. However, the relevant data such as length-length and length-weight relationships do not exist for most of the key species in Lake Kivu. The present study generated morphometric and body weight data for Limnothrissa miodon (n=82), Lamprichthys tanganicanus (n=55), Haplochromis vittatus (n=51) and Haplochromis graueri (n=34) from Lake Kivu. Length-weight relationships (W=aLb) were highly significant for all species (p < 0.0001), high adjusted R2 = 78 to 98% of the variance in weight explained by total length. Negative allometric length-weight relationships were found with regression slope (b) values of 2.7 for Limnothrissa miodon, 2.8 for H. graueri, and 2.8 for L. tanganicanus, and positive (b=3.4) for Haplochromis vittatus. Length-length relationships were highly significant for all species (p ≤ 0.0001), except for the relationship between total and caudal length for L. miodon, and total and caudal peduncle length for L. tanganicanus, both not significant at p > 0.05. The highest R2 was for the relationships between total and standard length for H. vittatus, and total and fork length for L. tanganicanus. No description of length-length relationships exists for these species in literature or in FishBase database. The data generated in the current study will be used to assess changes in fish populations over time.

Population parameters have been studied in nine of the 21 species of barracudas reported globally. Along the Bay of Bengal, Sphyraena putnamae (Jordan and Seale, 1905) forms a significant fishery; however, no information exists globally with respect to its growth, mortality and exploitation. This maiden study details the population dynamics analysed from samples collected from trawlnetters, gillnetters and hooks and lines along the western Bay of Bengal during January 2017 to December 2019. The mean fork length in the catch was 50.8 cm with the largest individual measuring 108.0 cm, the highest ever length recorded for the species. von Bertalanffy growth equation derived is Lt = 113.87 [1 - e -0.23 (t + 0.0636)]. The fishery was dominated by 1-4 year old age classes and lifespan estimated was 12.98 years. Year-round recruitment with the major peak producing 60.87% of the annual recruits was observed from February to June. Natural, fishing and total mortalities were 0.46, 0.25 and 0.71 per year, respectively. Exploitation rate (E) estimated was 0.35 with the exploitation ratio (U) being 0.18. Though the current status indicates that the stock is underexploited, it is however prudent to adopt a precautionary approach, considering the small size as well as age of exploitation, through adoption of measures such as increase in mesh size of trawlnetters and spatio-temporal fishing restrictions in nearshore nursery waters.

Selectivity is a fishing gear characteristic capable of catching fish of a specific size and species from the existing population distribution. Mesh size is one of the important factors that influence gillnets’ selectivity, because different length-classes of fish are caught by them. This report focuses on the selectivity of two mesh sizes of gillnets (8.89 cm and 10.16 cm) on mackerel's catch and constructing a gillnet in Sungailiat waters. Experimental fishing methods and selectivity analysis were used for the fishing gear’s more selective preparation, if the largest fishing ratio's value at the fork length (L) is high and the standard deviation value (S) is closer to 1. It is concluded that to be more selective a largest S (L) value of 0.999267194 at fork length (L=54.95 cm), and with a larger value of S (L) 0.997096071 and with (L=66.55 cm) for mesh Sizes 8.89 cm and 10.16 cm, respectively. Resumo A seletividade é uma característica das artes de pesca capazes de capturar peixes de determinado tamanho e espécie da distribuição populacional existente. O tamanho da malha é um dos fatores importantes que influenciam a seletividade da rede de emalhar. Devido ao tamanho diferente, eles pegam vários tipos de peixes. Este trabalho centra-se na seletividade de dois tamanhos de malha de emalhar (8,89 e 10,16 cm) na captura de cavala e na construção de uma rede de emalhar nas águas de Sungailiat. O método de pesca experimental e a análise de seletividade foram usados para a preparação mais seletiva das artes de pesca, se o valor da maior razão de pesca para o comprimento do garfo (L) for alto e o valor do desvio padrão (S) for mais próximo de 1. Conclui-se que para ser mais seletivo dev ter um maior valor S (L) de 0,999267194 no comprimento do garfo (L = 54,95 cm), um maior valor S (L) 0,997096071 e com (L = 66,55 cm) para o tamanho da malha 8,89 cm e 10,16 cm respectivamente.

Tetrapturus belone is endemic to the Mediterranean and it is more common in central parts. It is considered very rare in the Levant. On 20 October 2020, a specimen of Tetrapturus belone with 176 cm Lower Jaw Fork Length (LJFL) and weighing 26 kg was captured by a trammel net from the coast of Karantina Island, Urla at a depth of 11 m. This is the second record of the epipelagic T. belone entering the shallow waters of İzmir Bay, nine years after its first record in the same area. This ichthyologic note presents a new occurrence of the Mediterranean spearfish as an incidental catch from the small scale fishery in a certain coastal area of Urla, Izmir Bay.