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Southern Distinct Population Segment (sDPS) green sturgeon spawn solely in one stretch of the Sacramento River in California. Management of this spawning habitat is complicated by cold water temperature requirements for the conservation of winter-run Chinook salmon. This study assessed whether low incubation and rearing temperatures resulted in carryover effects across embryo to early juvenile life stages on scaling relationships in growth and metabolism in northern DPS green sturgeon used as a proxy for sDPS green sturgeon. Fish were incubated and reared at 11 °C and 15 °C, with a subset experiencing a reciprocal temperature transfer post-hatch, to assess recovery from cold incubation or to simulate a cold-water dam release which would chill rearing larvae. Growth and metabolic rate of embryos and larvae were measured to 118 days post hatch. Reciprocal temperature transfers revealed a greater effect of low temperature exposure during larval rearing rather than during egg incubation. While 11 °C eggs hatched at a smaller length, log-transformed length-weight relationships showed that these differences in developmental trajectory dissipated as individuals achieved juvenile morphology. However, considerable size-at-age differences persisted between rearing temperatures, with 15 °C fish requiring 60 days post-hatch to achieve 1 g in mass, whereas 11 °C fish required 120 days to achieve 1 g, resulting in fish of the same age at the completion of the experiment with a ca. 37-fold difference in weight. Consequently, our study suggests that cold rearing temperatures have far more consequential downstream effects than cold embryo incubation temperatures. Growth delays from 11 °C rearing temperatures would greatly increase the period of vulnerability to predation in larval green sturgeon. The scaling relationship between log-transformed whole-body metabolism and mass exhibited a steeper slope and thus an increased oxygen requirement with size in 11 °C reared fish, potentially indicating an energetically unsustainable situation. Understanding how cold temperatures affect green sturgeon ontogeny is necessary to refine our larval recruitment estimations for this threatened species.

This study analysed commercial 'Srdelara' purse seine landings in the Central Eastern Adriatic from November 2020 to March 2022. The observed commercial landings demonstrated typical seasonal variations, with a peak from September to November and the lowest landings recorded from spring to early summer. Sardines dominated the purse seine landings, comprising 97.9% of the total landing, followed by anchovies at 1.3%, with occasional by-catches or other species. Biological analysis involved collecting samples of eight pelagic fish species (sardine, anchovy, round sardinella, Atlantic bonito, Atlantic horse mackerel, Atlantic mackerel, chub mackerel and bogue) captured by the aforementioned fishing gear during the study period. The length frequency distributions of the investigated fish species were predominantly unimodal, with the exception of the Atlantic horse mackerel. Moreover, the length–weight relationships indicated isometric growth for each examined species. Stable isotope analysis revealed overlapping isotopic niches among the eight analysed fish species, with estimated mean trophic positions ranging from 3.0 to 4.7, indicating consumption of prey across approximately two trophic levels. The round sardinella and bogue had the smallest isotopic niche, while Atlantic mackerel had the widest one. This study highlights the need for further research to evaluate the observed overlap among pelagic species, particularly between small and medium-sized pelagic fish, as this interaction could significantly impact their biomass. Determining the extent of this overlap is crucial for improving management strategies and ensuring the sustainability of pelagic fish stocks in the Adriatic Sea. [ABSTRACT FROM AUTHOR]

A population of teleost fish stone moroko (Pseudorsabora parva) belonging to a Romanian freshwater pond located in Gorj County was analysed in order to reveal the length-weight relationship and condition factor, during two sampling seasons: October 2023 and February 2024. Positive allometric growth was estimated for 418 P. parva collected in 2023 (TW = 0.0065xTL 3.305 ; TW = 0.003 x SL 3.3946 ), while a negative allometric growth pattern was established for 764 P. parva collected in 2024 (TW = 0.0122xTL 2.7309 ; TW = 0.0252 x SL 2.5731 ). The values for condition factor K ranged between 0.47 and 0.74 (2023) and 0.31 and 1.47 (2024). For all individuals included in this study, the values for slope b were within the expected range of 2.5-3.5. In 2023, with b greater than 3, the growth type was estimated as positive allometric, while in 2024, the b lower than 3 indicated a hypoallometric growth type. On the other hand, in April 2024, a questionnaire was created in order to investigate the human knowledge about the traits of stone moroko in Romania. The surveyed fishermen appreciated both the initiative to address the impact of this invasive fish species and the integration of educational information in the questionnaire. Analysing the received answers, it was confirmed that people are aware about the necessary to apply methods in order to limit the reproduction of the stone moroko in Romania. [ABSTRACT FROM AUTHOR]

The sipuncula is an important ecological and economical resource to the inter-tidal ecosystem and humans due to its environmental functions and nutritional as well as medicinal values. Thus, the current study intends to determine systematic validity and to assess the weight-length relationship of the sipuncula living along the central coast of Vietnam. Species identity is evidenced by the key features of external morphology and internal anatomy. The results show that all these sipuncula have striking similarities to the sipuncula Siphonosoma australes (Keferstein, 1865), which has greater than 100 fibrous tentacles around their mouth and 15-17 longitudinal bands running along the body wall. Besides, we detected significant differences body mass, body length, introvert length, BM/BL and IL/BL ratios but not trunk length and diameter, number of tentacles, and longitudinal muscular bands of those thriving at different habitats. Additionally, we examined the growth pattern for the Vietnamese sipuncula using a least-squares regression model computed for weight-length relationships. The BM - BL relationship exhibited a significantly linear regression and a negative allometric growth pattern, indicating faster length increment compared to weight. The present study has contributed important information for assessing the status and density of the S. australe population from the central coast of Vietnam locally and the Indo-West Pacific region generally. [ABSTRACT FROM AUTHOR]

Lane snapper Lutjanus synagis (Linnaeus 1758) is abundant in Northeastern Brazil and economically relevant to the artisanal fishery. Population and reproductive aspects of lane snapper wereinvestigated to assist assessment. Lane snappers were acquired in Pernambuco (n = 406) from 2013 to 2015. Sex ratio is close to 1 : 1 (213 males and 179 females). For males, the total length, TL (mode) ranges from 16.3–27.8 cm (20.4 cm). For females, TL ranges from 17.0–29.9 cm (21.0 cm). The species have negative allometric growth (b < 3). The length that 50% of the population reach maturity (L50) using TL is 17.7 cm for both sexes. Macroscopical and microscopical gonadal stages are described per sex, and the gonadosomatic index indicates that reproduction happens during the dry season, between September and March, and two maturational peaks are observed, the first between September and November and the second between January and March. [ABSTRACT FROM AUTHOR]

Sillago muktijoddhai is a marine fish found along the Bay of Bengal in Bangladesh and the coast of India. However, detailed information on its reproductive biology, length-weight relationship, and feeding habits is lacking. To fill this gap in literature, a research was conducted from August 2022 to October 2023, during which 444 individuals were collected from the Cox's Bazar coast of the Bay of Bengal, Bangladesh. The total length and weight of the fish ranged from 51.23 to 200.5mm and 2.47 to 71.73g, respectively. Analysis of the sex ratio revealed a dominance of males over females, with a ratio of 1.36:1 (X² = 10.41, P< 0.05). The condition factors indicated that males exhibited a better growth pattern than females. The gonadosomatic index suggested that the peak breeding season occurs in November. Histological observations identified four distinct stages of gonadal development for males: immature, maturing, ripe, and spent. For females, the stages were immature, maturing, mature, and ripe. The absolute fecundity ranged from 6,164 to 30,555 eggs per ovary, with a mean value of 12,176 ± 1,050. The regression coefficient (b) for the length-weight relationship was 3.213, indicating a positive allometric growth pattern. Morphometric analysis of the mouth and relative gut length revealed that S. muktijoddhai is a bottom feeder with carnivorous habits. Gut content analysis showed that crustaceans formed the major component of its diet, although zooplankton, gastropods, bivalves, and sand were also present. [ABSTRACT FROM AUTHOR]

A 2-week rapid fishery assessment using various sampling gears was conducted to collect life-history data on rednose labeo Labeo rosae and Mozambique tilapia Oreochromis mossambicus in Loskop Dam on the Olifants River, Mpumalanga Province, South Africa. These native species were the two most-abundant fish species caught in the impoundment during the study. Both species displayed a bimodal population size distribution comprised of recent recruits and large-sized individuals. Isometric growth (b value ∼3), an asymptotic length (L∞) of 447 mm, and length at 50% sexual maturity (Lm50) of 198 mm were estimated for L. rosae. Isometric growth, L∞ of 451 mm, and Lm50 of 124 mm were estimated for O. mossambicus. This rapid assessment at Loskop Dam produced sets of life-history parameters comparable to those previously reported for these two species in Flag Boshielo Dam, ∼80 km downstream. [ABSTRACT FROM AUTHOR]

Squids play vital ecological and economic functions as keystone species in marine food webs and integral components of global capture fisheries. However, a comprehensive understanding of their diversity and life history characteristics in Indonesian waters is still poorly understood. This study aimed to identify squids that inhabited Java's northern and southern coasts and examine their growth pattern through morphometric analysis. Six hundred eighteen squid samples were collected fishers caught from May to September 2022 in Blanakan and Palabuhanratu Bay, representing two areas of interest. The body size and the shape of sucker rings of squids were observed using morphometric method. Kruskall-Wallis test, Principal Component Analysis, and Spearman's correlation were performed to investigate morphometric variation and relationships. The length-weight relationships were estimated for each species. This study reported three species of squid on the north and south coasts of Java, namely the mitre squid (Uroteuthis chinensis), the Indian squid (Uroteuthis duvaucelii), and the purpleback flying squid (Sthenoteuthis oualaniensis). There were significant differences observed in ten morphometric variables among the three species of squid (p < 0.05), with fin width, fin length, and sucker ring teeth identified as the key distinguishing feature for the squids. Spearman's correlation indicated stronger associations between mantle and fin variables (ρ = 0.666-0.967, p < 0.05) than those between mantle and head variables (ρ = 0.380-0.864, p < 0.05). Mantle length-weight relationships revealed a hypoallometric growth pattern for U. chinensis and U. duvaucelii, while S. oualaniensis exhibited an isometric growth pattern. The finding of this study provides valuable insights concerning the growth of squids that reflect variation in ontogenic development, trophic ecology, and environmental conditions in Indonesian waters. [ABSTRACT FROM AUTHOR]

The present study describes the length-weight relationship (LWR) and condition factor of Xenentodon cancila (Hamilton, 1822) on a seasonal basis from upper Brahmaputra basin, NE India. All the relationships between total length and total weight are found to be highly significant (P<0.01) for both the sexes of the species throughout the period of study. The species exhibited allometric growth for most part of the study and found not to be strictly in accordance with the predicted cube law. Seasonal variation in the calculated "b" values for the species also observed ranging from 2.098 (in winter) to 3.401 (in pre-monsoon). Similarly, mean value of relative condition factor (Kn) ranges between 0.991 (in monsoon) and 1.149 (in winter) with minimum seasonal variations for both the sexes while mean value of Fulton's condition factor (K) is found to be slightly higher in females than males except for monsoon. [ABSTRACT FROM AUTHOR]

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In the Mediterranean, the bluespotted cornetfish Fistularia commersonii Rüppell, 1838, presents a minor socioeconomic impact and the assessment of any environmental impact requires more relevant data. The congeneric red cornetfish Fistularia petimba Lacepède, 1803, has expanded its distribution range within the basin but only small numbers have been reported to date. A total of 207 individuals of F. commersonii were collected between April 2021 and March 2022 from the Levantine coast of Rhodes and 92 more from various locations. Additionally, 13 individuals of Fistularia petimba were caught in March 2024 from the Aegean coasts of the island. We aim to assess the current progression of the population of the two cornetfish, the possible further exploitation of F. commersonii to boost the local fishing economy, their possible dietary overlaps and to add valuable biological and ecological data. In F. commersonii, male to female ratio (1:1.33) significantly departed from 1:1, with length–weight relationships exhibiting positive allometric growth. Six age groups were identified. The highest reproductive intensity was observed during summer. The onset of sexual maturity was estimated at 65.52 cm in total length (1.8 years). Longevity was estimated at 11.1 years with females growing larger than males. The exploitation rate (E = 0.47) indicated that the population is underexploited. The optimum and target fishing mortality were higher in comparison with the present fishing mortality (F = 0.48), indicating a potential for commercial exploitation of the species. For F. petimba, the sex ratio was 1:2.25. The species preys on crustaceans, followed by fish and molluscs. The finding of Vanderhorstia mertensi (Klausewitz, 1974) in the stomach content of both cornetfishes constitutes the second published record for Hellenic waters and the first for the Dodecanese Islands.

Graphical Abstract Highlight Research • The results of this research showed that allometric growth in males and females had negative allometric growth characteristics. • The growth condition index in male and female fish is dominated by thin and fat body shapes.The maximum length growth (L∞) and growth speed of males is higher than that of females. • Total mortality and fishing mortality for males is higher than for females, but natural mortality for females is higher than for males. • The exploitation rate of males and females is in the Under-exploitation category because the E value is

This study analyzes the species composition, length–weight relationship (LWR), condition factor, and morphometric and meristic characteristics of eleven freshwater fish species in Kota Panjang Reservoir, Indonesia. Fresh specimens were collected from September 2023 to February 2024. Results show that among the sampled species, two belong to Order Anabantiformes, three to Order Siluriformes, and six to Order Cypriniformes. The Order Siluriformes has the lowest species composition, with Hemibagrus wyckii at 3.09%, while the Order Cypriniformes has the highest, with Barbonymus schwanefeldii at 15.25%. The LWR coefficient b ranges from 1.693 to 3.151. Of the species studied, only Hemisilurus heterorhynchus (b = 2.174), Clarias teijsmanni (b = 2.046), Anabas testudineus (b = 2.375), Labiobarbus festivus (b = 2.305), and Rasbora argyrotaenia (b = 1.693) fall outside the expected range of 2.5 < b less than < 3.5. One species exhibits a positive allometric growth (+), seven show a negative allometric growth (−), and three display an isometric growth (I). Fulton's condition factor (Kc) averages between 0.73 ± 0.15 and 4.96 ± 0.63, indicating morphological variation. The allometric condition factor (Ka) ranges from 0.87 ± 0.18 to 26.25 ± 4.05, reflecting differences in resource availability and competition. Relative condition factor (Kn) values range from 1.00 ± 0.09 to 2.51 ± 0.55, indicating good growth. Morphometric analysis shows that Rasbora argyrotaenia has the smallest average total length, head length, and body depth, while Hemibagrus wyckii has the largest. The results provide new data on the LWR, condition factor, and morphometric characteristics of eleven selected freshwater fish species in Kota Panjang Reservoir, Indonesia, and offer up‐to‐date information on the remaining species in the study area. These findings could have a significant impact on species stock assessments and help identify priority species for domestication. [ABSTRACT FROM AUTHOR]

Length-weight relationships (LWRs) were estimated for 30 fish species, i.e. Abbottina rivularis, Alburnus chalcoides, A. oblongus, A. taeniatus, Carassius gibelio, Channa argus, Cottus spinulosus, Cyprinus carpio, Gambusia holbrooki, Glyptosternon oschanini, Gobio lepidolaemus, Hemiculter leucisculus, Hypophthalmichthys nobilis, Iskandaria kuschakewitschi, Luciobarbus conocephalus, Micropercops cinctus, Opsariichthys bidens, Pelecus cultratus, Petroleuciscus squaliusculus, Pseudorasbora parva, Rhinogobius cf. lindbergi, Rhodeus ocellatus, Sabanejewia aralensis, Salmo oxianus, Schizothorax eurystomus, Triplophysa daryoae, T. elegans, T. ferganaensis, T. labiata, and T. strauchii from the Upper Syr Darya drainage, Uzbekistan. The LWR parameters were determined using a linear logarithmic regression model of the weight against the length, in which values for the slope of the regression, b, that were higher and lower than three indicated positive and negative allometric growth, respectively. The estimated values of parameter b ranged from 2.719 (Cyprinus carpio) to 3.442 (Pelecus cultratus). The correlation coefficient (r2) values varied from 0.945 to 0.998, indicating a strong positive relationship between the length and weight. This study established new maximum TLs for three species (Glyptosternon oschanini, Gobio lepidolaemus, and Petroleuciscus squaliusculus) and presented LWRs for the first time for 17 fish species in the inland waters of Uzbekistan, including seven previously unreported in FishBase. [ABSTRACT FROM AUTHOR]

From December 2012 to June 2014, 796 Pacific guitarfish were caught in 183 fishing sets in northern Peru. Catch occurred in 86.3% of sets. Most individuals caught were mature with a bias toward males. The mean total length for females and males was 83.4 cm, and 91.1 cm, respectively. The capture per unit effort (CPUE) was 12.6 ± 3.4 guitarfish (km.12 h)−1. The length–weight relationships showed that this species presents a sexual dimorphism in growth. These results support the importance of Sechura Bay as a key area for this species. This study represents the first species‐specific fishery data for the Pacific guitarfish. [ABSTRACT FROM AUTHOR]

The present study examined the morphometric characteristics of the European pilchard, Sardina pilchardus (Walbaum, 1792) from Béni-Saf Bay (Algeria), to address the lack of data concerning the exploitation of their stocks in this area. A total of 306 specimens were examined, consisting of 49.35% males, 45.10% females, and 5.56% undetermined individuals. The overall sex ratio was 1.09, slightly favoring males (χ2 = 0,5848; P<0.05). Sixteen measurements were carried out for each specimen; the total length of the observed fish ranged from 6.4 to 22.7 cm. The length-weight relationship for S. pilchardus was determined using the regression equation Wt=aLtb. The model parameters for the relationships (LWR) indicated a positive allometric growth for both sexes (t-test, P<0.05); the coefficient of determination (R²) was 0.97 for males and 0.99 for females, indicating a strong correlation between length and weight. The equations of the length-weight relationship were Wt = 0.0057*Lt3.0981 for males and Wt = 0.0066*Lt3.0602 for females. The results of the model parameters for the relationships Y=aLtb indicate a strong correlation between all morphological measurements and total length. Regardless of sex, all parameters showed a lower growth allometry (negative allometry), with statistically significant results observed in both sexes (t-test, P<0.05). The present study demonstrated that male and female S. pilchardus from Béni-Saf Bay (Algeria) showed sexual dimorphism in favor of the females (F-test, P<0.05). Females fish have longer fin sizes than males and longer heads than males. Furthermore, females possess a longer upper jaw compared to males. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to determine the length-length, length-weight relationships and condition factor values of the Uranoscopus scaber, which is distributed in the Cape Jason from the Central Black Sea. Within the scope of the study, a total of 112 fish individuals, 61 females and 51 males, caught using nets were examined. Standard length (SL), total length (TL) measurements and fish weights (W) of fish individuals were determined. Since statistical differences (t-test, P<0.05) were determined between the measurements of male and female individuals, evaluations were carried out separately for females, males and all individuals. The length-weight relationship equations and correlation coefficients of female, male and all U. scaber individuals are W=0.0099TL3.220 (r²=0.963), W=0.0239TL2.876 (r²=0.953), and W=0.0142TL3.079 (r²=0.956) respectively. It was determined that female individuals of the U. scaber showed a positive allometric growth in this habitat, while male individuals showed a negative allometric growth. Total length-standard lengtht relationship equations and correlation coefficients of female, male and all individuals of U. scaber are TL=1.2009SL+0.81 (r²=0.992), TL=1.267SL+0.0903 (r²=0.992), and TL=1.2269SL+0.5198 (r²=0.992), respectively. The average condition factor values of female, male and all U. scaber individuals were calculated as 1.7979±0.0255, 1.7340±0.0257, and 1.7688±0.0183, respectively. The determined parameters are the first data for the Cape Jason population of U. scaber in the Central Black Sea. [ABSTRACT FROM AUTHOR]

In the Mediterranean, the bluespotted cornetfish Fistularia commersonii Rüppell, 1838, presents a minor socioeconomic impact and the assessment of any environmental impact requires more relevant data. The congeneric red cornetfish Fistularia petimba Lacepède, 1803, has expanded its distribution range within the basin but only small numbers have been reported to date. A total of 207 individuals of F. commersonii were collected between April 2021 and March 2022 from the Levantine coast of Rhodes and 92 more from various locations. Additionally, 13 individuals of Fistularia petimba were caught in March 2024 from the Aegean coasts of the island. We aim to assess the current progression of the population of the two cornetfish, the possible further exploitation of F. commersonii to boost the local fishing economy, their possible dietary overlaps and to add valuable biological and ecological data. In F. commersonii, male to female ratio (1:1.33) significantly departed from 1:1, with length–weight relationships exhibiting positive allometric growth. Six age groups were identified. The highest reproductive intensity was observed during summer. The onset of sexual maturity was estimated at 65.52 cm in total length (1.8 years). Longevity was estimated at 11.1 years with females growing larger than males. The exploitation rate (E = 0.47) indicated that the population is underexploited. The optimum and target fishing mortality were higher in comparison with the present fishing mortality (F = 0.48), indicating a potential for commercial exploitation of the species. For F. petimba, the sex ratio was 1:2.25. The species preys on crustaceans, followed by fish and molluscs. The finding of Vanderhorstia mertensi (Klausewitz, 1974) in the stomach content of both cornetfishes constitutes the second published record for Hellenic waters and the first for the Dodecanese Islands. [ABSTRACT FROM AUTHOR]

Le gobie de Sarasin, Mugilogobius sarasinorum (Boulenger, 1897) est un poisson d'eau douce endémique du Lac Poso, dans la région centrale du Sulawesi, Indonésie. FishBase répertorie M. sarasinorum comme une espèce de pêche commerciale. En 2019, le statut de conservation de cette espèce sur la Liste rouge de l'UICN a été révisée de Vulnérable (VU) à En Danger (EN), en se basant sur des menaces telles que la pression de la pêche, la dégradation de l'habitat et l'introduction d'espèces exotiques, mais les données sur M. sarasinorum sont limitées. Cette étude visait à apporter des données afin de remédier à ce manque. Des spécimens ont été collectés Octobre 2020 (N = 86; longueur totale TL 19,6-44,6 mm; SL 16,8-41,3 mm). Un morceau de tissu d'un des spécimens a été conservé dans de l'éthanol à 96 % pour le barcode ADN (COI, séquençage Sanger). Afin de confirmer l'identification de cette espèce, la séquence a été blastée sur GenBank, puis une analyse phylogénétique a été réalisée dans MEGA 11. Dix-huit caractères morphométriques ont été mesurés et la formule méristique a été déterminée. Le sex-ratio (M:F) était biaisé en faveur des mâles (3,4:1). La relation longueur-poids (W = aLb) est allométrique négative (b = 2,363). [ABSTRACT FROM AUTHOR]

Invasive fish species pose several threats to aquatic biodiversity and health, necessitating a good understanding of their biology and ecology. This study aims to understand the biology of invasive fish species collected from a Langat River tributary, Selangor, focusing on their growth, reproduction, and feeding habits. Fish and water samples were collected between March and August 2022. A total of 171 specimens were recorded, including 71, 55, and 45 individuals of Pterygoplichthys disjunctivus, P. pardalis, and Oreochromis sp. The b values for length-weight relationships of P. disjunctivus, P. pardalis, and Oreochromis sp. were 2.79, 2.92, and 2.89, respectively. The mean condition factor for Oreochromis sp. was significantly (p < 0.05) higher than that of the other two species. There were no significant differences between the observed and expected number of males and females for all three species. The females had higher mean gonadosomatic index values compared to males. The mean fecundity for P. disjunctivus, P. pardalis, and Oreochromis sp. were 973 ± 596, 10562 ± 830, and 1052 ± 1068, respectively. The most important stomach contents of the three species were detritus, mineral particles, and diatoms, with a higher proportion of mineral particles found in the diets of P. disjunctivus and P. pardalis. The information on growth patterns, reproductive strategies, and dietary preferences provides valuable insights for controlling their invasion of local rivers. [ABSTRACT FROM AUTHOR]

Pseudorasbora parva (Temminck and Schlegel, 1842) has a significant potential to spread outside of its current locations and regions, all-continents-spanning invasive range. The invasion of P. parva has threatened the existence of native species. Therefore, evaluation of the condition and fitness of the invasive P. parva population in different regions is necessary. However, no systematic reports of the P. parva length-weight relationships (LWRs) around the world has been documented, especially comparing indigenous and non-indigenous populations. Thus, the goal of the current study was to offer a systematic report of P. parva LWRs worldwide and a comparison of P. parva LWRs in native and non-native regions. In the present results, P. parva showed positive-allometric growth, it became more rounded as the length increases, and both native and invasive populations showed similar growth patterns and form factor. Considering its invasive potential, the harmful effects of this alien species cannot be ignored. The present research will also focus on eliminating or mitigating the adverse effects caused by the further expansion of the species through a series of prevention and management strategies proposed. [ABSTRACT FROM AUTHOR]

Context: The quagga catshark (Halaelurus quagga) is a small-sized (~370-mm total length), deep-water catshark (Family: Pentanchidae), assessed as Data Deficient on the IUCN Red List. Aim: We aimed to bridge critical knowledge gaps on aspects of the life history and exploitation of H. quagga to make a meaningful Red List assessment, and develop management plans. Methods: Specimens landed as bycatch in three harbours along the Laccadive Sea coast of south-western India were examined to gather the first information on exploited length classes and aspects of reproductive biology. Key results: Halaelurus quagga had a female-dominated sex ratio, a positively allometric growth in females, and isometric growth in males. Mature H. quagga males ranged between 294 and 336 mm, and females between 315 and 370 mm, with pregnant females carrying two, three or four egg cases with embryos in each uterus. Conclusions: This study provides the first information on the biology and exploitation of H. quagga , showing that the species is landed (and discarded) as bycatch in trawl fisheries, with the catches comprising a significant amount of reproductively active individuals. Implications: The intense deep-sea bottom-trawling off south-western India is a major threat to H. quagga , and, if left unmanaged, could likely trigger a threatened category on the IUCN Red List. The first study on the exploitation levels and aspects of biology of Halaelurus quagga , a poorly known deep-water catshark, showed a female-dominated sex ratio, a positively allometric growth in females and isometric growth in males. Mature H. quagga males ranged between 294 and 336 mm, and females between 315 and 370 mm, with pregnant females carrying two, three or four egg cases, with embryos in each uterus. This species is landed (and discarded) as bycatch in shrimp fisheries, with the catches comprising a significant amount of reproductively active individuals. [ABSTRACT FROM AUTHOR]

The study was conducted in the Terie River between January and April 2022. The objectives of the study were to assess the fish species composition, determine the length-weight relationship and condition factor and assess the water quality of the river using international water quality guideline for aquatic life. Gillnets with different mesh sizes, 4, 6, 8 and 10 cm were used to collect fish specimens in both dry and wet seasons. Immediately after capture, the total length (TL) and total weight (TW) of each individual were measured in centimeters and grams, respectively, and their relationship was determined using the power function. The physicochemical water quality parameters were analyzed using standard procedures and wagtech portable water quality Kits and Secchi Disk apparatus. A total of 667 fish specimens were collected from the Terie River, 410 and 257 in dry and wet seasons respectively. A total of six fish species, Oreochromis niloticus, Labeobarbus intermedius, Labeobarbus nedgia, Labeobarbus beso, Clarias gariepinus, and Ramius loti were recorded. For length-weight relationship and condition factor analysis, more abundant fish species (O. niloticus and L. intermedius) which were found in both seasons were selected. The length and weight relationship of L. intermedius were TW = 0.0073TL3.04 in dry and TW = 0.0337TL2.59 in we season indicated isometric and negative allometric growth respectively. While O. niloticus showed negative allometric growth, TW = 0.096TL2.44 and TW = 0.0335 TL2.76 in dry and wet seasons, respectively. The mean Fulton condition factor (FCF) of L. intermidus were 0.85 ± 0.03 and 0.94 ± 0.25 in dry and wet seasons, respectively. The FCF of O. niloticus was 1.70 ± 0.13 and 1.73 ± 0.12 in dry and wet seasons respectively. Except for ammonia, the physicochemical water quality parameters were with the permissible limit for aquatic life and are suitable for fishes Terie River. The river has commercially important fish specimens that could be used for food security and livelihood improvement. However, there is very limited fishing activity in the river due to less awareness on the value of fishes. Therefore, sustainable fishery development should be done in the river.

Highlight Research • The mitre squid (Uroteuthis chinensis), the Indian squid (Uroteuthis duvaucelii), and the purpleback flying squid (Sthenoteuthis oualaniensis) were identified. • Morphometric differences among three squid species were analyzed. • Microanatomy observations on the shapes of the sucker rings were important for species identification. • Hypoallometric and isometric growth patterns were observed. Abstract Squids play vital ecological and economic functions as keystone species in marine food webs and integral components of global capture fisheries. However, a comprehensive understanding of their diversity and life history characteristics in Indonesian waters is still poorly understood. This study aimed to identify squids that inhabited Java's northern and southern coasts and examine their growth pattern through morphometric analysis. Six hundred eighteen squid samples were collected fishers caught from May to September 2022 in Blanakan and Palabuhanratu Bay, representing two areas of interest. The body size and the shape of sucker rings of squids were observed using morphometric method. Kruskall-Wallis test, Principal Component Analysis, and Spearman's correlation were performed to investigate morphometric variation and relationships. The length-weight relationships were estimated for each species.. This study reported three species of squid on the north and south coasts of Java, namely the mitre squid (Uroteuthis chinensis), the Indian squid (Uroteuthis duvaucelii), and the purpleback flying squid (Sthenoteuthis oualaniensis). There were significant differences observed in ten morphometric variables among the three species of squid (p < 0.05), with fin width, fin length, and sucker ring teeth identified as the key distinguishing feature for the squids. Spearman's correlation indicated stronger associations between mantle and fin variables (Ï = 0.666-0.967, p < 0.05) than those between mantle and head variables (Ï = 0.380-0.864, p < 0.05).Mantle length-weight relationships revealed a hypoallometric growth pattern for U. chinensis and U. duvaucelii, while S. oualaniensis exhibited an isometric growth pattern. The finding of this study provides valuable insights concerning the growth of squids that reflect variation in ontogenic development, trophic ecology, and environmental conditions in Indonesian waters.

Background Nile tilapia ( Oreochromis niloticus) is predominant cultured species in aquaculture. However, there is a scarcity of literature regarding relationship between guava and star gooseberry leaf extract and the condition factor. Thus, the present study aims to investigate the effect of guava and star gooseberry leaf extract-supplemented diets on the specific growth rate, length-weight relationship, and condition factor of Nile tilapia. Methods Six hundred and thirty Nile tilapia (8.7±0.4 g) were randomly distributed among twenty-one tanks (30 fish per tank) within a recirculation system. Over a 60-day period, the fish were fed diets supplemented with 5g/Kg and 10g/Kg of guava leaf extract (GLE-5, GLE-10), star gooseberry leaf extract (SGLE-5, SGLE-10), and a mixture of both (MxLE-5, MXLE-10). Subsequently, specific growth rate, length-weight relationship, and condition factor were determined. Results After 60 days, the specific growth rate was significantly higher in all the GLE, SGLE, and MxLE groups compared to the control group. The final lengths and weights differed significantly both in the control group and all the GLE, SGLE, and MxLE groups. The analysis of the regression equation indicated a positive correlation (r = 0.970, 0.977, 0.976, 0.974, 0.974, 0.974, and 0.969) between the length and weight of Nile tilapia in the control group and in all the GLE, SGLE, and MxLE groups. The regression exponent “ b” values in all the GLE, SGLE, and MxLE groups were >3, indicating a positive allometric growth pattern in Nile tilapia compared to the control ( b=2.866), which exhibited a negative allometry. The final condition factor values did not differ significantly in either the control group or any of the plant extract groups. Conclusions Nile tilapia exhibited positive allometric growth patterns and maintained good health when fed with GLE, SGLE, and MxLE groups. Therefore, these plant extracts demonstrate suitability for commercial Nile tilapia production.

Length-weight relationship (LWR) is an important parameter in the fish biology study since genetic and environmental factors govern fish growth. This study aimed to understand the growth pattern of Sardinella lemuru, related to different locations and seasons, to estimate S. lemuru fishing grounds with good growth patterns of this fish. Specimens (n=3282) of S.lemuru catch were collected at Pengambengan fishing port, Bali, from April 2022 to January 2023. S.lemuru landed at Pengambengan fishing port were caught from three zones of the fishing grounds in Bali Strait(zones 2, 5, and 6). Monthly data of the study area's environmental parameters, including SST and Chl-a, were downloaded from the Ocean Color-SeaDAS website. The relationship between LWR and the environmental parameters was statistically analyzed using the Partial Least Square (PLS) model. The LWR parameters, intercept 'a' and regression coefficient 'b', varied from 0.00261 to 0.12607 and 2.201 to 3.382, respectively. The condition factor ranged from 0.14 to 1.84. Simultaneously, both environmental variables play an important role in the growth of S.lemuru in all zones of the fishing grounds. The PLS analysis of the regression coefficient of the SST and CHL -a variable has a positive relationship with LWR. Environmental variables proved to have an indirect effect on the growth pattern of S. lemuru. [ABSTRACT FROM AUTHOR]

The present study presents length-weight, length-length, length-girth relationships, and biometry of male and female specimens of saddled seabream, Oblada melanurus(Linnaeus, 1758), in the Turkish Aegean Sea. The length-length and length-weight relationships were calculated by measuring 516 individuals. The total length values of all male and female O. melanurus specimens were in the range of 17.2-30.7 and 18.5-30.0 cm, respectively, and the mean values were 21.84±2.04 and 22.44±2.12 cm, respectively. The length-weight relationships were W=0.0110TL3.057 for males, W=0.0114TL3.043 for females, and W=0.0089TL3.122 for all the specimens. The results denoted a high correlation (r²=0.966; p<0.001) in the length-length relationships. Furthermore, 287 individuals (105 females and 182 males) were examined for length-girth relationships and biometric analyses. Ten morphometric characters were analyzed to analyze biometry. In conclusion, no statistically significant differences were determined in morphology between the sexes (p<0.05). [ABSTRACT FROM AUTHOR]

The study of length-weight relationship and condition factor was carried out on of freshwater catfish, Clupisoma garua. Altogether 280 samples were collected from three different rivers of North India (Gomti, Ganga and Rapti). The value of b ranges from 2.571-2.720 for the length-weight relationship in the current study. The growth pattern showed significant deviation from isometric value (b=3), therefore all the three populations are supposed to follow negative allometric growth pattern. The coefficient of determination (r2) was found to be in the range of 0.8059-0.8587. The value of condition factor in the present study was found to be more than '1' in all the three populations of the fish which indicated the good health conditions. The present study is considered to be important for assessment of the biology of the fish that could help in conservation and management of C. garua in the North Indian Rivers. [ABSTRACT FROM AUTHOR]

Copyright of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Ürünleri Dergisi is the property of Ege Journal of Fisheries & Aquatic Sciences (EgeJFAS) / Su Urunleri Dergisi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Black bullhead Ameiurus melas is a widespread invasive fish in Europe and is considered an ecological and economic threat. Yet, sporadic data are available on its life-history traits. This study assessed the fecundity, growth, and body condition of black bullhead in three oxbows in Hungary. Samples were collected in the resting (October) and pre-spawning (April) periods. Considerable negative allometric growth was observed (b slope ranged between 1.64 and 1.67). The Fulton's condition factor was lower than any previously reported data (mean = 1.01; SD = 0.09). The mean male : female ratio of the three populations was 1.18:1. Mean absolute fecundity was 3,319 eggs (SD = 1521; range = 1,111-12,727), and mean relative fecundity was 78.8 eggs g-1 (SD = 21.8; range = 34.8-146.0). The mean oocyte diameter was 0.39 mm in autumn and 0.41 mm in spring. Oocyte size positively correlated with body length. The mean standard length at age was 76.5-81.00 mm at 1+, 126.23-134.35 at 2+, 153-154.5 mm at 3+, and 180-181 mm at 4+. Our results confirmed the phenotypic plasticity of black bullhead out of its native range. [ABSTRACT FROM AUTHOR]

A population of weatherloach has been detected in the Schadgraben stream at Geispolsheim, near Strasbourg (Rhine catchment, eastern France) in autumn 2021 and identified as the European weatherloach Misgurnus fossilis. Another sixty-three weatherloaches were caught in this location the 19 May 2022. The examination of morphological and molecular data on preserved specimens allows to identify this population as the dojo weatherloch Misgurnus anguillicaudatus, an invasive species. The length-weight relationship of this population highlights its good health and establishment. A review of the knowledges about this invasive species is also done. Monitoring must be put in place in order to follow its propagation, threatening native fishes like the endangered M. fossilis. [ABSTRACT FROM AUTHOR]

The present study reveals toxic metals, proximate composition, and growth conditions in seven fish species, aiding their nutritional importance and conditions. The samples of seven different small indigenous fish species, including Xenentodon cancila, Glossogobious giuris, Pseudambassis ranga, Puntius dorsolis, Mystus vittatus, Dawkinsia filamentosa, and Dawkinsia tambraparaniei, were collected in river Gadananathi, Tamilnadu, India. A total 14 fish samples were analyzed for lead, cadmium, and copper using atomic absorption spectrometry. The standard procedures were used to determine the length–weight and proximate composition of the seven fishes. The findings revealed that the seven fish species had variable amounts of metal buildup. Cu levels were highest in D. tambraparniei gills and lowest in M. vittatus gills and livers; nonetheless, substantial amounts of Cu were found in P. dorsalis livers. In the length–weight correlations of the regression parameters of coefficient value r2, the "a" and "b" values revealed a positive allometric growth rate in all fish species except G. giuris and M. vittatus. However, X. cancila had the highest composition in the proximate analysis, while D. tambraparniei and D. filamentosa had the highest protein content mean value at a significant level (P ≤ 0.05). Overall, discrepancies in nutritional content might be related to species, environmental circumstances, fish age and size, and food availability. [ABSTRACT FROM AUTHOR]

Faunus ater is a pachychilid gastropod known to inhabit brackish water habitats of Western Indo-Pacific countries. This study aimed to analyse the morphometric relationships and condition factor of F. ater collected from the Edava-Nadayara brackish water lake of Kerala, India. Hydrographic parameters of sampling stations were recorded. A total of 1,522 specimens were collected every month from March 2019 to February 2020. The mean values recorded for total length, shell width, body whorl length, opercular length, opercular width, and total weight were 45.38±13.44 mm, 14.47±3.88 mm, 20.81±5.83 mm, 7.71±3.08 mm, 4.62±1.62 mm, and 6.97±3.72 g, respectively. The length-weight relation was obtained as Log W= -1.005+2.871 Log L. The b value (<3) indicated a negative allometric growth of the organism. Regression analysis of other morphometric measurements also showed a positive correlation (P<0.001). The analysis of Fulton's condition factor indicated a state of wellbeing of F. ater in this habitat, with condition factors ranging from 5.87 to 6.99 spatially and 5.48 to 7.00 temporally. This study provides the first detailed investigation of morphometric relationships and condition factors in F. ater. [ABSTRACT FROM AUTHOR]

Fish of the genus Tlaloc are distributed from southern Mexico to Central America and are a distinctive example of the endemic fauna of the Mesoamerican highlands, which has been scarcely studied in Mexico. The present study provides basic life-history data for the species Tlaloc hildebrandi, T. candalarius, and T. labialis, which are native to the headwaters of the Grijalva-Usumacinta basin in southeastern Mexico. We collected 918 specimens to determine their Length-Weight Relationship (LWR), Relative Condition Factor (Kr), sex ratio, Gonadosomatic Index (GSI), fecundity, and size at first sexual maturity. Both sexes of all species had positive allometric growth, except for T. candalarius females (isometric). Mean Kr and sex ratio values differed significantly among species. Females’ GSI values differed significantly among species but were highest during the dry season in all three species. Absolute fecundity was positively correlated with standard length and weight. Sexual maturity was reached at different lengths among species. Based on these results, we suggest that all three species present an opportunistic life strategy, which is very common in fish of the order Cyprinodontiformes. These results represent a first contribution on the life-history of this group of fish and provide basic information that is fundamental to ensuring their conservation.

Background Nile tilapia (Oreochromis niloticus) is predominant cultured species in aquaculture. However, there is a scarcity of literature regarding relationship between guava and star gooseberry leaf extract and the condition factor. Thus, the present study aims to investigate the effect of guava and star gooseberry leaf extract-supplemented diets on the specific growth rate, length-weight relationship, and condition factor of Nile tilapia. Methods Six hundred and thirty Nile tilapia (8.7±0.4 g) were randomly distributed among twenty-one tanks (30 fish per tank) within a recirculation system. Over a 60-day period, the fish were fed diets supplemented with 5g/Kg and 10g/Kg of guava leaf extract (GLE-5, GLE-10), star gooseberry leaf extract (SGLE-5, SGLE-10), and a mixture of both (MxLE-5, MXLE-10). Subsequently, specific growth rate, length-weight relationship, and condition factor were determined. Results After 60 days, the specific growth rate was significantly higher in all the GLE, SGLE, and MxLE groups compared to the control group. The final lengths and weights differed significantly both in the control group and all the GLE, SGLE, and MxLE groups. The analysis of the regression equation indicated a positive correlation (r = 0.970, 0.977, 0.976, 0.974, 0.974, 0.974, and 0.969) between the length and weight of Nile tilapia in the control group and in all the GLE, SGLE, and MxLE groups. The regression exponent “b” values in all the GLE, SGLE, and MxLE groups were >3, indicating a positive allometric growth pattern in Nile tilapia compared to the control (b=2.866), which exhibited a negative allometry. The final condition factor values did not differ significantly in either the control group or any of the plant extract groups. Conclusions Nile tilapia exhibited positive allometric growth patterns and maintained good health when fed with GLE, SGLE, and MxLE groups. Therefore, these plant extracts demonstrate suitability for commercial Nile tilapia production.

For management of fish stocks, assessing the various parameters of population dynamics are regarded as being extremely important. Under this backdrop the population dynamics parameters viz. growth, mortality and recruitment of Pethia conchonius, inhabiting the Dal Lake of Kashmir Himalayas were analysed using FiSAT II software. The analysed specimens were collected from five different sites within the lake and exhibited a total weight range of 0.3 to 6.4 g and a total length range of 3.1 to 7.8 cm. The relative condition factor for the fish was reported to be 1.11. The growth parameter i.e., asymptotic length, age at zero length, growth performance index and growth constant were reported to be 10.0 cm, –0.75 years, 1.48 and 0.30 year–1 respectively. The total mortality of 1.49 year–1, consisting of natural mortality of 0.88 year–1 and fishing mortality of 0.61 year–1 was reported. An exploitation rate of 0.41 is suggestive of a less exploited state of the fish. The length at first maturity was found to be higher than the length at first capture, a condition that can disturb the stock, as such the utility of a net with relatively larger mesh size is advisable. The current research on the population dynamics of P. conchonius can be used as the baseline data for its management practices.

Knowledge about the population dynamics within a specific spatial area is vital for the effective planning and management of important fishery resources. Population parameters, including the asymptotic length (L∞), growth coefficient (K), mortalities (Z, F, and M), recruitment pattern, exploitation level (E), and yield per recruit (Y'/R), of the tropical oyster Magallana bilineata in Mengkabong Bay, Tuaran, Malaysia were analyzed by using the FiSAT software, using on the monthly shell length-frequency data collected from April 2019 to March 2020. A total of 435 oysters with shell lengths ranging from 3.64 to 11.16 cm were analyzed. Habitat water temperature, salinity, dissolved oxygen, hydrogen ion concentration (pH), and chlorophyll concentration were measured at 29.0–33.7 °C, 26.68–35.74 psμ, 3.18–6.99 mg/L, 6.57–8.29 and 1.51–98.93 μg/L, respectively. The logarithmic relationship between the length and weight of Log W = 1.9055 Log L + 0.1049 (R2 = 0.5431) with exponent b of 1.9055 for combined sexes showed a negative allometric growth (b

Biometric evaluation and reproductive biology of Oreochromis niloticus were studied from Geray Reservoir. Between November 2021 and August 2022, 316 O. niloticus specimens were collected from this reservoir. The observed male to female sex ratio was 1:1.14, which was statistically insignificant compared with the hypothetical 1:1 sex ratio (X2 = 1.27, p > 0.05). The length-weight relationship was curvilinear with allometric growth (b < 3) and statistically significant from the expected isometric growth pattern (b = 3). The regression equation for females was TW = 0.0264TL2.72 (r2 = 0.90, n = 168), males (TW = 0.0183TL2.79, r2 = 0.93, n = 148), and combined sexes (TW = 0.0229TL2.76, r2 = 0.91, n = 316). Gonadosomatic index (GSI) ranged from 0.8 to 1.4 (males) and 1.8 to 4.9 (females). The breeding season lasted from March to June, with a GSI peak in April. Fecundity ranged from 279 to 1,528 eggs./fish, with a mean of 1,025 eggs./fish. The correlation between absolute fecundity and length was more significant (F = 0.76TL2.8, R2 = 0.94, p < 0.05) than with weight (F = 17.683TW0.71, R2= 0.92, p < 0.05). This study provides basic information on the biology of O. niloticus in the Geray Reservoir for future fishery management tools for the conservation and utilization of this valuable freshwater fish.

Background Nile tilapia ( Oreochromis niloticus) is predominant cultured species in aquaculture. However, there is a scarcity of literature regarding relationship between guava and star gooseberry leaf extract and the condition factor. Thus, the present study aims to investigate the effect of guava and star gooseberry leaf extract-supplemented diets on the specific growth rate, length-weight relationship, and condition factor of Nile tilapia. Methods Six hundred and thirty Nile tilapia (8.7±0.4 g) were randomly distributed among twenty-one tanks (30 fish per tank) within a recirculation system. Over a 60-day period, the fish were fed diets supplemented with 5g/Kg and 10g/Kg of guava leaf extract (GLE-5, GLE-10), star gooseberry leaf extract (SGLE-5, SGLE-10), and a mixture of both (MxLE-5, MXLE-10). Subsequently, specific growth rate, length-weight relationship, and condition factor were determined. Results After 60 days, the specific growth rate was significantly higher in all the GLE, SGLE, and MxLE groups compared to the control group. The final lengths and weights differed significantly both in the control group and all the GLE, SGLE, and MxLE groups. The analysis of the regression equation indicated a positive correlation (r = 0.970, 0.977, 0.976, 0.974, 0.974, 0.974, and 0.969) between the length and weight of Nile tilapia in the control group and in all the GLE, SGLE, and MxLE groups. The regression exponent ' b' values in all the GLE, SGLE, and MxLE groups were >3, indicating a positive allometric growth pattern in Nile tilapia compared to the control ( b=2.866), which exhibited a negative allometry. The final condition factor values did not differ significantly in either the control group or any of the plant extract groups. Conclusions Nile tilapia exhibited positive allometric growth patterns and maintained good health when fed with GLE, SGLE, and MxLE groups. Therefore, these plant extracts demonstrate suitability for commercial Nile tilapia production.

Spiny lobster species Panulirus versicolor and P. femoristriga in Donggala waters are reported to experience growth overfishing and recruitment overfishing. If this phenomenon continues, it will gradually reduce the spiny lobster population and result in an overall population decline. Information on reproductive biology is needed in the formulation of management and conservation policies for spiny lobsters in Donggala Waters, Central Sulawesi Province. The purpose of this study was to compare and analyze aspects of reproductive biology such as sex ratio, length-weight relationship, and spiny lobster condition factors. The research was conducted from July to December 2020 in the waters of Kabonga Village, Banawa Subdistrict, and Limboro Village, Central Banawa Subdistrict, Donggala District, Central Sulawesi Province. Reproductive biology data analysis applies several analytical models such as Chi-square, linear regression, Fulton condition factor, and Withney-Mann Test. The results showed no difference in sex ratio (balanced population) with negative allometric growth pattern and Fulton's condition factor in good condition (wellbeing) throughout the study in both P. versicolor and P. femoristriga. Population balance is important to ensure the continuity of recruitment, which is supported by adequate food availability, thus maintaining the stability of the spiny lobster population. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Anatolian Environmental & Animal Science is the property of Bulent Verep and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study describes the length-weight relationship (LWR) and condition factor for three important freshwater fish species (Garra mcclenlandi, Danio aequipinnatus and Crossochelius latis) collected from drainage system of Mon, Nagaland, India from 2022 to 2023. During survey a total of 278 specimens of mixed population were examined. 95% confidence level of b values (regression coefficient) of Length-Weight Relationship (LWR) ranged from 2.3616 - 3.1485 indicating positive allometric pattern of growth for D. aequipnnatus, while G. mcclenlandi and C. latis showed negative allometric growth. The highest condition factor (k) 1.0993 was observed in D. aequipnnatus, lowest in G. mcclenlandi with 0.8126 while r2 > 0.90 for all the three species. [ABSTRACT FROM AUTHOR]

Knowledge about the population dynamics within a specific spatial area is vital for the effective planning and management of important fishery resources. Population parameters, including the asymptotic length (L8), growth coefficient (K), mortalities (Z, F, and M), recruitment pattern, exploitation level (E), and yield per recruit (Y'/R), of the tropical oyster Magallana bilineata in Mengkabong Bay, Tuaran, Malaysia were analyzed by using the FiSAT software, using on the monthly shell length-frequency data collected from April 2019 to March 2020. A total of 435 oysters with shell lengths ranging from 3.64 to 11.16 cm were analyzed. Habitat water temperature, salinity, dissolved oxygen, hydrogen ion concentration (pH), and chlorophyll concentration were measured at 29.0-33.7 °C, 26.68-35.74 psµ, 3.18-6.99 mg/L, 6.57-8.29 and 1.51-98.93 µg/L, respectively. The logarithmic relationship between the length and weight of Log W = 1.9055 Log L + 0.1049 (R2 = 0.5431) with exponent b of 1.9055 for combined sexes showed a negative allometric growth (b < 3), indicating that the oysters in Mengkabong Bay are skinny. Several management measures have been proposed to promote high meat growth, including the use of genetically selected seeds, selection of new farming sites and adoption of grow-out methods that favour high meat growth. Asymptotic length (L8) and growth coefficient (K) of the von Bertalanffy Growth Formula (VBGF) for M. bilineata were estimated at 12.13 cm and 1.00 yr-1, respectively. The theoretical ages at length zero (t0) (0.0487) were estimated by substituting L8 and K in Pauly's equation. The sizes attained by M. bilineata were 3.76, 5.04, 6.13, 7.05, 7.83, and 8.49 cm at the end of 2, 4, 6, 8, 10, and 12 months, respectively. The calculated growth performance index (f) for M. bilineata in Mengkabong Bay was 2.168, while the estimated lifespan was 3 years. The recruitment pattern was observed year-round, with higher recruitment activities in September-October 2019 and January 2020. The total mortality (Z) was analyzed using the lengthconverted catch curve and estimated at 3.04 yr-1, fishing mortality (F) at 0.63 yr-1, and natural mortality (M) at 2.41 yr-1. The lower exploitation rate (0.21) compared to the recommended 0.5 and Beverton and Holt's estimated maximum allowable limit of exploitation rate (Emax) of 0.587 indicated that the M. bilineata stock in Mengkabong Bay was under-exploited. Several recommendations that could aid in the development of M. bilineata in Mengkabong Bay include promoting local oysters through collaboration with leading hotels and restaurants, developing food processing technology for downstream products, and establishing a sanitation programme that includes monitoring and enforcing sanitary conditions in the culture, harvest and processing sectors. [ABSTRACT FROM AUTHOR]

Channa marulioides is one of the species that is facing a population decrease due to high fishing activity. This study aims to determine the value of the length-weight relationship and condition factors of C. marulioides in the Kapuas River as a relevant conservation effort. Several sampling areas in this study were used to represent the Kapuas River, including Kapuas Hulu River in Kapuas Hulu Regency, Putussibau District; The central part of the waters area of Sintang Regency in Sintang Regency; and in the downstream waters of Pontianak City. The study carried out the sampling by analyzing the criteria for specimens with a dimension weight > 500 grams and length > 30 cm, with the same amount for each sex. The results showed that the growth type in the upper and middle waters was positive allometric with a value of b 3.1; however, it is negative allometric in the middle and upstream waters with b values of 2.5 and 1.7. After research, the condition factor of the upstream and middle waters was observed to be in good condition with a value of 1. However, in the downstream waters, the condition of the fish was rather bad with a value below 1, namely 0.99. The study concludes there is a decrease in the quality of the aquatic environment and the food availability from the middle waters to the downstream. This is what underlines conservation efforts in the form of domestication activities within the scope of structured fish farming. [ABSTRACT FROM AUTHOR]

Certain benthic polychaetes, such as species within the genus Namalycastis, are employed in the diet of gravid shrimps in aquaculture due to their amino acids and highly unsaturated fatty acid content, enhancing the quality of gravid shrimp. Despite its importance in the rapidly developing shrimp culture industry, the population parameters of this economically valuable species are unknown. Therefore, the present study examines the population parameters of Namalycastis fauveli to assess its occurrence, growth, recruitment, exploitation level, and stock status in Bangladesh. Monthly samplings of N. fauveli and environmental variables were collected from five sites of the Cox's Bazar coast using a square-shaped mud corer with a 0.093 m2 (or 1.0 ft2) mouth opening from August 2020 to July 2021 to measure or estimate. Within the 8.0–30.0 cm depth range of the intertidal zone, polychaete samples were collected from the sediment. The results showed negative allometric growth (b < 3), but there was a significant L–W relationship (p < 0.05, r2 = 0.43 to 0.94). The estimated L∝, K, and ϕ were 22.05 cm, 0.99 year−1, and 2.69, respectively, while total mortality (Z) was 4.56 year−1. It was calculated that the fishing mortality and capture probability proportionally increased with the total length at a certain age. Recruitment mostly occurred in October and March, and temperature had a greater impact than salinity. The evaluated exploitation level (E = 0.57) indicated that the stock was overexploited. Thus, the above results provide some valuable information for shrimp farmers and stakeholders, as well as for policymakers in the move towards restoration, species conservation, and efficient management of N. fauveli natural stocks. [ABSTRACT FROM AUTHOR]

Intertidal fish are a key component of littoral food webs, contributing to the diets of birds and commercial fish species. Ascertaining their growth and condition can therefore help understand the health status of local communities.Lipophrys pholis is a fish of the rocky intertidal with a wide distribution throughout the North‐eastern Atlantic (NE Atlantic) that has been recommended for use as an indicator in the environmental biomonitoring of marine ecosystems. However, it is unclear yet if this species is sensitive to the reserve effect.In this study, the size, growth and body condition of specimens caught at protected and unprotected rocky shores of two contrasting marine provinces of the NE Atlantic were analysed to address whether L. pholis is sensitive to the reserve effect.L. pholis were larger, grew faster in weight and were in better condition in the protected shores of both provinces. A faster growth rate was observed in the populations of the warmer province.Inshore waters of unprotected sites in the Northern European Seas sampled in this study have recently been incorporated into a protected area. Thus, these results can help assess the success of the marine conservation programme and the time L. pholis needs to improve its population's health at these shores.Regulating access to shores to avoid trampling and harvesting is a protection measure that can help enhance the health and conservation of L. pholis populations. [ABSTRACT FROM AUTHOR]