Fulton's Condition Factor Research Articles

Assessing integrated biomarkers of triplefin fish Forsterygion capito inhabiting contaminated marine water - A multivariate approach

The presence of multiple chemicals in aquatic ecosystems makes evaluation of their real impact on the biota difficult. Integrated biomarkers are therefore needed to evaluate how these chemicals contribute to environmental degradation. The aims of the present study were to evaluate responses to and effects of marine pollution using a series of biomarkers through multivariate analyses. Transcriptional responses of cyp1a (cytochrome P450), mt (metallothionein), vtg (vitellogenin) and cyp19b (cytochrome P450 aromatase); branchial and hepatic histological alterations; and Fulton condition factors (CF) were evaluated, as well as the metals and polycyclic aromatic hydrocarbons present in Forsterygion capito in Auckland, New Zealand. Sites were selected along a contamination gradient: four highly contaminated sites and four less contaminated. Molecular responses with a higher relative expression of the mt and cyp1a genes were detected at a highly contaminated site (Panmure). Several histological lesion types were found in the livers of fish inhabiting both types of sites, but gill lesions were present primarily at highly contaminated sites. In terms of general health status, the lowest CF values were overwhelmingly found in fish from the same site (Panmure). The multivariate approach revealed that telangiectasia and hyperplasia were associated with the presence of chemicals, and these showed negative associations with the CF values, with fish from three highly contaminated sites being most affected. In conclusion, the multivariate approach helped to integrate these biological markers in this blennioid fish, thus providing a more holistic view of the complex chemical mixtures involved. Future studies should implement these analyses.

Bir Ada Ekosistemindeki (Gökçeada, Türkiye) Dört Aşılanmış Tatlısu Balığı Türünün Kondisyon, Boy-Boy ve Boy-Ağırlık İlişkileri

The present study aims to investigate the condition, length-weight (LWRs) and length-length relationships (LLRs) of four introduced freshwater fish species (Carassius gibelio, Cyprinus carpio, Gambusia holbrooki, and Pseudorasbora parva) inhabited in the inland waters of Gökçeada (Çanakkale, Turkey). Fish samples were collected using electrofishing from one lentic (Büyük Stream) and four lotic (Aydıncık, Dereköy, Gökçeada, and Uğurlu Reservoirs) ecosystems between April 2019 and September 2020. The calculated values of parameter b in the LWRs were 3.275 and 3.230 for G. holbrooki (Uğurlu and Büyük populations, respectively), 3.031 and 2.937 for C. carpio (Aydıncık and Dereköy populations, respectively), 3.129 for C. gibelio and 3.047 for P. parva. Values of Fulton's condition factor (K) varied between 1.72 ± 0.23 (P. parva, Gökçeada population) and 3.60 ± 0.33 (C. carpio, Dereköy population). The coefficients of correlation (r) for all the LLR equations were greater than 0.95 and significantly linear. The present study provides the first knowledge about the selected biological parameters for four introduced freshwater fish species in Gökçeada.

Hazardous pollutants in the environment: Fish host-parasite interactions and bioaccumulation of polychlorinated biphenyls

The present paper reports on the interrelationships of fish, parasites and the bioaccumulation of hazardous organic compounds in the Zemplínska Šírava water reservoir in eastern Slovakia, which is heavily polluted with polychlorinated biphenyls (PCBs). The concentrations of these contaminants were measured in various fish matrices (dorsal and abdominal muscle tissues, hepatopancreas, intestine wall and adipose tissue) of the freshwater bream, Abramis brama (Cyprinidae), and in its intestinal parasite Caryophyllaeus laticeps (Cestoda), which was used for the first time as a model for a PCB bioaccumulation study. Regarding the fish, the highest concentrations of PCBs were found in the intestine, followed by hepatopancreas and muscle tissues. The amounts of PCBs were higher in abdominal muscles than in their dorsal parts. Concentrations of ∑PCBs above the limits set by European regulations were detected in both muscle parts in the fish, confirming the persistent unfavorable conditions in this locality and high risk for biota and humans. Based on bioconcentration factor values (BCFs), PCBs reached much higher levels in cestodes compared to bream matrices. Some significant differences in PCB amounts between infected and uninfected bream were determined. Fulton's condition factor (CF) significantly differed in infected and non-infected fish (p ˂ 0.05), with CF values surprisingly lower in fish free of parasites compared to parasitized fish, which suggests a “mutualistic” relationship between the parasite and its host.

Biological Aspects of Waanders’s Hard-lipped Barbs (Osteochilus waandersii) in Tambatan River, North Sumatera, Indonesia

Background: Waanders’s hard-lipped barbs or scientifically known as Osteochilus waandersii belong to the family Cyprinidae with the potamodromous category. This fish can be found in the Tambatan river. It has the potential for commercial consumption or ornamental fish. Methods: This study was conducted in the Tambatan river from November to January 2021. The determination of three research stations was carried out using a purposive sampling method. Sampling was undertaken using cast nets. Furthermore, data analyzed were growth patterns, condition factors, and gonad maturity levels. Results: The growth patterns of male (1.944) and female (2.379) Osteochilus waandersii were in a negative allometric category. Besides, The Fulton's condition factor for male fish ranged from 0.42 - 3.43 with an average of 1.05, while that for female fish ranged from 0.59 - 3.67 with an average of 1.47. The result of the observation on the gonad maturity level for male and female O. waandersii in the Tambatan river indicated that they were dominated by fish with gonad maturity stage I (immature). Conclusions: Waanders’s hard-lipped barbs O. waandersii found were in the stage towards the mature level.

Aksu Çayı (Adıyaman- Türkiye) Garra turcica Karaman, 1971 popülasyonu için bazı popülasyon dinamiği parametreleri

In order to determine some biological characteristics of Aksu stream Garra turcica population, 168 individuals were examined between 2013-2014. The ages of the examined individuals are between 0 and IV. it was determined to be between. Total lenght and weight values were calculated as 3.9-16.6 cm (8.54 ± 2.36 cm) and 0.81-58.50 g (9.40 ± 8.30 g), respectively. The length-weight relationship was determined W = 0,0145L2.9172. Growth parameters were estimated as L∞ = 21.77 cm, k = 0.31 and to = -0.836. Growth performance index and Fulton's condition factor were calculated as Φꞌ = 2.17 and K = 1.23, respectively. Death rates due to total, natural and fisheries were calculated as Z: 0.94, M: 0.63, F: 0.30, and the level of utilization from stock as E: 0.32, respectively.

Populasi Kepiting Bakau (Scylla serrata) di Perairan Muara Sungai Barumun Kabupaten Labuhanbatu Ditinjau dari Pola Pertumbuhan dan Faktor Kondisi

Mangrove crab (Scylla serrata) is one of the prima donna sources of protein caught by fishermen around mangrove forest waters in the waters of the Barumun River Estuary, Labuhanbatu Regency. This study aims to inform about condition factors, growth patterns of crab populations, and reproductive aspects in the form of abundance of Gonad Maturity Level (TKG). Determination of 3 sampling points is done by using purposive random sampling method. Scylla serrata sampling was carried out using Bubu. Data analysis presents information on the abundance of gonadal maturity level, growth pattern, and Fulton condition factor (K), which is presented quantitatively. The results showed that male and female Scylla serrata growth patterns were categorized as negative allometric b < 3, with carapace width growth being faster than weight gain. Fulton condition factor (K) values obtained ranged from 50.14-132.75 for male Scylla serrata, and female ranged from 80.34-123.94. The gonadal maturity level of Scylla serrata was dominated by TKG II crabs, and the lowest abundance of gonad maturity was in TKG IV crabs. This indicates that, in December-February, the condition of the Scylla serrata population around the mangrove forest waters of the Barumun river estuary, is predicted to be in the stage of adult dominance that is ready to reproduce and prepare to spawn.

Bioekologi Udang Swallow (Penaeus merguiensis)

This study aims to examine the bioecological aspects of P. merguiensis around the estuary of the Berombang river in terms of growth patterns, the abundance of gonad maturity and condition factors. The method used in this research is purposive sampling. Shrimp sampling was carried out using arad nets which were stocked at low tide. The results showed that the composition of the abundance of the gonadal maturity level of P. merguiensis shrimp at three sampling stations was dominated by immature gonadal shrimp (BMG) to TKG 2. The growth pattern of P. merguiensis shrimp based on the length-body weight relationship in the Berombang river was classified as positive allometric. Fulton condition factor (K) ranged from 0.14 to 4.68, with an average total body length ranging from 2.35 to 13.70 cm. In conclusion, the condition factor of P. merguiensis shrimp in the Berombang river was classified as a plump category with shrimp weight gain being faster than body length growth, with female plumpness being greater than males.
 Keywords: Fulton Condition Factor, Gonad Maturity, Growth Pattern, P. merguiensis, Berombang River

Faktor Kondisi dan Pola Pertumbuhan Oxygaster anomalura

This study aims to obtain information related to the biological and ecological aspects of the Oxygaster anomalura in the Mailil River, Bandar Kumbul Village. The method used in this research is exploratory. Sampling was done using a fishing rod. The growth pattern was calculated using the length-weight relationship using the Linear Allometric Model (LAM), while the condition factor used the Fulton formula (K) and relative weight (Wr). The results showed that as many as 30 samples of Sulum Fish (Oxygaster anomalura) were caught during the study. Analysis of the length-weight relationship showed a negative allometric relationship with a value of b=1.94 (b>3). The Fulton condition factor (K) value is 1,195, while the value of the relative condition factor (Wr) is 169.42. In conclusion, the Mailil River as an ecosystem and habitat for O. anomalura fish is balanced.
 Keywords: Condition Factor, Oxygaster anomalura, Mailil River

Conjoint applications of meta-analysis and bioinformatic data toward understanding the effect of nitrate on fish

The extensively accumulation of nitrate in different water resources is currently regarded as one of the most predominant threats facing aquatic organisms on worldwide scale. In recent years, a growing body of evidences have been attempting to uncover the influences of nitrate on fish growth and health, thereby evaluating its environment security. However, the systematic assessment and intrinsic mechanism of such influences are apparently devoid. Hence, this investigation employed systematic analysis, meta-analysis and bioinformatic analysis to evaluate the nitrate biotoxicity. We first speculated two levels of nitrate concentration according to forty-four published bibliographies. Systematic analysis indicated that the broad variations of fish sensitivity to chronic and acute nitrate exposures were found in juvenile and larval stage, respectively, comparing to egg. Meta-analysis further revealed that survival rate, CF and SGR were significantly improved in low nitrate concentration during chronic exposure. Such improvements were reflected by Total mean differences (TMD) and 95% CIs (Confidence Intervals): Survival rate (−4.06 [−7.67, −0.45]), Fulton's condition factor (CF) (−0.03 [−0.03, −0.02]) and Specific growth rate (SGR) (−0.10 [−0.16, −0.04]). To trace the impact, the alternations of molecular expression and histology in brain, gill, liver, intestine, and blood suggested that the chronic and acute nitrate exposures could result in abnormal tissue structures and molecular dynamics. Moreover, omics analysis via integrating intestinal microbiome (microbial composition; %) and liver transcriptome (Gene Ontology: biological processes) revealed that the low concentration exposure induced a weakly immune response in fish liver and it matched to the intestinal immune response. Overall, current study has filled the gaps in the field of nitrate toxicity. It could also provide a novel insight for the evaluation of pollutant toxicity on aquatic species.

Integrated Biomarker Response for Environmental Assessment Using the Gastropod Phorcus turbinatus along the Northern and the Northeastern Coasts of Tunisia.

This work aims to assess the spatial and temporal variations of four biomarkers activities and to integrate their biological responses in a battery using the gastropod Phorcus turbinatus. The monitoring was carried out during the period between April 2014 and January 2015 at six stations along the northern and the northeastern coasts of Tunisia. The Fulton condition factor was estimated and the activities of catalase, acetylcholinesterase and glutathione-S-transferase were evaluated by spectrophotometry. A multi-biomarker battery approach was used to assess ecosystems’ condition and to identify environmental impacts on the organisms. The results suggest that the enzymatic activities of CAT and GST depend especially on seasons. As for AChE activity, it was similar between seasons and stations. The values of the integrated biological response were maximal at Jarzouna in summer and at Sidi Daoued in winter, indicating the presence of severe stressors suffered by the organisms. This perturbation may be due to the enrichment of the waters by xenobiotics, namely polycyclic aromatic hydrocarbons, insecticides, phosphate wastes, PCBs and pesticides. Thus, P. turbinatus seems to be a good bioindicator of chemical pollution, constituting an adequate tool for a bio-monitoring program.

Effect ofSaccharomyces cerevisiae addition to feed contaminated with aflatoxin B1 on the health and performance indices of tambaqui (Colossoma macropomum) fingerlings

The objective of this study was to evaluate the effects of the addition ofSaccharomyces cerevisiae to feed contaminated with aflatoxin B1 (AFB1) on the performance and health of tambaqui fingerlings. A fully randomised study design was used, represented by four treatments: (T1) with 0.0 μg/kg of AFB1 and 0.0 colony forming unit (cfu)/g of yeast (control); (T2) with 0.0 μg/kg of AFB1 and 106 cfu/g of yeast; (T3) with 100 μg/kg of AFB1 and 0.0 cfu/g of yeast and (T4) with 100 μg/kg of AFB1 and 106 cfu/g of yeast, with four repetitions per treatment. Over a period of 34 days, 192 fingerlings with an initial weight of 2.9±0.2 g and length of 26.1±1.3 mm were used, distributed in 16 tanks with 12 fish per experimental unit. The following parameters were evaluated: water quality, zootechnical performance, histopathological analysis, counting and isolation of yeasts from the feed and intestine. No significant differences were observed (P>0.05) in the initial weight, initial length, final length, specific growth rate, mean length gain, Fulton condition factor (K Factor) or survival rate of the tambaqui fingerlings during the trial period. Statistical differences (P<0.05) were found between the treatments with respect to fingerling final weight, mean weight gain and average feed intake. Histopathological changes in the liver and kidney tissues from tambaqui fingerlings were more pronounced in T3 and T4. Based on histopathological findings, the yeast was unable to reduce the characteristic effects of aflatoxicosis in tambaqui fingerlings fed with 100 μg/kg AFB1. TheS. cerevisiae A8L2 strain was able to colonise the intestine of tambaqui fingerlings, however, its addition in conjunction with 100 μg/kg AFB1 to fingerling feed did not promote improvements in performance indices or the histopathological parameters of these animals.

The role of energy reserves in common carp performance inferred from phenotypic and genetic parameters

In temperate zones, energy reserves of fish are closely related to survival during the first winter of their life. In this study, the genetic and phenotypic background of the accumulation, mobilization and utilization of energy reserves was investigated in Amur mirror carp. To achieve this, the role of traits related to energy reserves on fish performance during the first winter and further periods of rearing was investigated. The experimental stock was established by four full-factorial matings of 5 dams and 10 sires to generate up to 200 full-sibling families. The offspring were sampled before and after the first winter rearing period. Seasonal variation in direct and indirect measures of energy status was examined using Fulton's condition factor (FC), hepato-somatic index (HSI), visceral index (VSI_NO), glycogen, fat and protein in hepatopancreas (HP) and muscle fat content. Other performance traits were also recorded (weight, resistance to koi herpesvirus disease). All traits related to energy reserves, except HP protein, were significantly lower after the first winter. Overall, HP glycogen and fat from muscle, HP and viscera were mobilized during winter. However, genetic correlations between same traits recorded in autumn and spring were lower than 0.8 for most of the traits, implying that not all families responded to overwintering in a similar manner. Heritability also differed before and after the first winter. Before the first winter, all traits had low to medium heritability (0.05–0.35), but after the winter the same traits were moderately or highly heritable (0.22–0.58). Interestingly, HP glycogen traits, unlike HP fat and HP protein, and HSI recorded in yearlings were positively genetically correlated with survival during the third growing season (rg = 0.49–0.72). This study provides the first evidence of a genetically based strategy for energy mobilization related to overwintering of common carp. Measuring of FC and HSI could be used to monitor the energy status of common carp and to provide a supplementary tool for management of carp stocks.

The addition of moringa flour (Moringa oleifera) to the diet of nile tilapia (Oreochromis niloticus) and its effect on productive parameters

Due to the importance of finding sustainable protein sources, that could partially or totally replace fish meal, several studies have demonstrated the potential of Moringa oleifera in Oreochromis niloticus diets. The aim of the present study was to evaluate the addition of four different percentages of M. oleifera flour in O. niloticus diets on productive parameters.  Water quality was monitored daily, and biometrics were carried out every 15 days.  Four isoproteic diets were formulated that included 30% total protein, and isoenergetic (3900 kcal/kg).  Moringa flour was included at percentages of 0%, 10%,15% and 20% (T0, T10, T15 and T20 treatments, respectively).  Growth development was evaluated for 60 days based on: specific growth rate (SGR), weight gain (WG), Fulton's condition factor (FC), absolute growth rate (AGR), food conversion rate (FCR) and survival rate (SR). Significant differences (p < 0.05) were observed between T0 and T15 with T30 and T45 treatments at 30 days, the first two showing the highest values. From 60 days onwards, there was a decreasing relationship between the inclusion level and the total weight. There was an inverse relationship between the inclusion of M. oleifera flour and the main growth parameters of O. niloticus, while there were no differences in terms of SR and FCR.

Length-weight relationship and condition factor of freshwater blenny Salaria fluviatilis (Asso, 1801) in Asi River (Hatay, Turkey)

In this study, a total of 109 specimens (57 female and 52 male) of Salaria fluviatilis were captured by tulle net and scooped net between October 2017 and March 2018 from the Asi River system, Turkey. The length-weight relationship was W =0.0013L3.054 (r²= 0.967) for both sexes with isometric growth. The values of the exponent b of the length-weight relationships (LWRs) were 3.055 for females and 3.052 for males. The b values for females, males, and both sexes were not significantly different from 3.0 (P>0.05). Fulton condition factor (CF) was calculated 1.3955±0.034 for females, 1.4495±0.042 for males and 1.4212±0.027, for both sexes. Estimations of LWRs and CF for both sexes of S. fluviatilis, captured from Asi River, were provided for the first time.

Effects of the cranial parasite Tylodelphys sp. on the behavior and physiology of puye Galaxias maculatus (Jenyns, 1842).

Diplostomatid digeneans are well-known manipulators of the behavior of their intermediate hosts. Unencysted metacercariae of Tylodelphys sp. inhabit the cranial cavity of the fish Galaxias maculatus; however, to date they have not been documented to alter their host behavior. The goal of this study was to evaluate the potential effects of Tylodelphys sp. inhabiting the cranial cavity of Galaxias maculatus on host physiology and swimming behavior as well as its reaction to a simulated predation attempt. Blind experiments in the lab were carried out on 56 fish that were filmed individually. The Fulton condition factor (K) was used as an approximation of nutritional status and a respirometry chamber was used to evaluate oxygen consumption rates of fish. Of the 56 fish, 21 were parasitized by Tylodelphys sp. (mean intensity = 30, range from 1 to 101). Parasitized and non-parasitized fish were similar in condition factor and oxygen consumption rates. Furthermore, the oxygen consumption rate of G. maculatus was not correlated with the abundance of Tylodelphys sp. However, parasitized fish more frequently swam close to the water surface, whereas non-parasitized fish more frequently swam at intermediate depths. When faced with a simulated predator attack, unparasitized fish showed more frequent fleeing behavior as well as a more intense post-fleeing activity. Collectively, these results suggest that Tylodelphys sp. inhabiting the cranial cavity of fish may alter their behavior predisposing them to predation by birds.

Acute toxicity and effects of the Roundup Transorb®, a glyphosate-based herbicide, on freshwater teleost matrinxã, Brycon amazonicus

The aim of this study was to evaluate the susceptibility of the Neotropical freshwater fish matrinxa, Brycon amazonicus, exposed to Roundup Transorb®, a newer commercial formulation 50% stronger than the ordinary mixtures and with a new technology for quicker absorption and faster translocation. The median lethal concentration (96 h-LC50) was determined, and the effects of a sublethal concentration on oxidative stress biomarkers were evaluated in the liver, gills, white muscle, and heart. During the acute toxicity test, fish mortality progressively increased with RT concentration along with behavioral abnormalities were detected. The calculated 96 h-LC50 value of RT was found as 1.21 mg/L. Fish exposed to 0.5 mg/L of RT (40% of 96 h-LC50) showed a significant increase in the hepatic somatic index (HSI) with a concomitant decrease in Fulton's condition factor (K). The sublethal exposure also induced significant increases (p < 0.05) in the hepatic lipid peroxidation (LPO) levels, reduced glutathione (GSH) content, and catalase (CAT) activity, with a concomitant decrease in the glutathione S-transferase (GST) activity. In the gills, RT exposure induced significant increases in the GST activity, GSH and LPO levels, whereas CAT activity was inhibited. RT also induced CAT and GST activities together with the content of GSH and LPO levels in the white muscle. On the other hand, significant decreases in the CAT and GST activities were detected in the heart with a marked increase in the GSH content and no changes in LPO levels. Therefore, the exposure to 0.5 mg/L of RT induced oxidative stress in the liver, gills and white muscle with tissue-specific responses related to antioxidant defenses. This study demonstrated that B. amazonicus is sensitive to Roundup Transorb® at sublethal and environmentally relevant concentrations, even at short-term exposures. The use of Roundup Transorb® should be carefully monitored due to its adverse non-target impacts.

Life‐history traits of three Ambassid fishes (Chanda nama, Parambassis lala and Parambassis ranga) from the Mathabhanga River, southwestern Bangladesh

ABSTRACTThe present study provides the first indication of the life‐history traits, including, population structure, growth pattern, condition factor, form factor (a3.0), size at first sexual maturity (Lm), natural mortality (MW) and optimum catchable length (Lopt), of three Ambassid (Chanda nama, Parambassis lala and Parambassis ranga) fishes from the Mathabhanga River in southwest Bangladesh. A total of 370 individuals were occasionally collected from August 2017 to July 2018 with cast nets, gill nets, square lift nets, and conical‐ and box‐traps. The total length (TL) ranged from 2.4 to 7.5 cm for C. nama, 1.9–3.8 cm for P. lala and 1.8–6.5 cm for P. ranga. The length‐frequency distributions (LFDs) showed the 4.0–5.0 cm TL size group for C. nama and the 3.0–4.0 cm TL size group were numerically dominant for P. lala and P. ranga. The length–weight relationships (LWRs) indicated isometric growth for C. nama, and positive allometric growth for P. lala and P. ranga. All the LWR values were very significant (p &lt; .001), with all r2 values &gt; .950. Based on the Spearman rank correlation test, body weight (BW) versus Fulton's‐condition factor (KF) was extremely correlated (p &lt; .001), indicating a better wellbeing for these species. The a3.0 value was 0.0082, 0.0138 and 0.0104 for C. nama, P. lala and P. ranga, respectively. Based on the maximum length (Lmax), the Lm was 4.4 cm TL for C. nama, 2.5 cm TL for P. lala, and 4.0 cm TL for P. ranga. Based on the asymptotic length (L∞), the Lm was 4.88 cm TL for C. nama, 2.63 cm TL for P. lala, and 4.28 cm TL for P. ranga. The MW value was 2.2, 3.3 and 2.7/year for C. nama, P. lala and P. ranga, respectively. The optimum catchable length (Lopt) was 5.36 cm TL for C. nama, 2.75 cm TL for P. lala and 4.65 cm TL for P. ranga. The findings of the present study should be very useful for effective and sustainable management of these fishes in the Mathabhanga River and the connecting ecosystems.

First report on reproductive features of the Hooghly croaker Panna heterolepis Trewavas, 1977 from the Bay of Bengal in relation to environmental factors.

This study highlights the reproductive biology of Hooghly Croaker, Panna heterolepis Trewavas, 1977 which is one of the dominant fish in the Bay of Bengal (Bangladesh) based on monthly sampling of 569 female individuals from January to December 2019. We observed the effect of different environmental factors (temperature, rainfall, dissolved oxygen, and pH) on the reproduction of P. heterolepis. Measurements of each individual like total length (TL) and body weight (BW) were taken by using of measuring board and digital balance. Gonads were carefully removed through ventral dissection from females and weighed to 0.01g accuracy. To assess the size at sexual maturity (Lm), spawning season, and its peak, the GSI (gonadosomatic index in %), MGSI (modified gonadosomatic index in %), and DI (Dobriyal index) were considered. Based on these indices, the Lm was documented 15.0cm in TL. Moreover, L50 was predicted by logistic calculation as 15.0cm TL. Furthermore, greater values of GSI, MGSI, and DI values denoted the spawning season as of January to July, with a peak in February. Additionally, Fulton's condition factor (KF) was significantly correlated with GSI values. In addition, GSI was statistically correlated with temperature. However, other environmental factors (rainfall, dissolved oxygen, and pH) did not show any significant relation with GSI. Finally, the outcomes of our study might be useful to carry out specific management programs for P. heterolepis in the Bay of Bengal and nearby aquatic ecosystem.

The length-weight relationship and condition factor of yellowspotted puffer Torquigener flavimaculosus Hardy &amp; Randall, 1983 in the Eastern Mediterranean (Yumurtalık Bight, Turkey)

The length-weight relationships (LWRs) of fish are helpful in fisheries science. A total of 504 yellowspotted puffer (Torquigener flavimaculosus) specimens (257 female and 247 male) were caught from the Yumurtalık coast of Turkey (Eastern Mediterranean Sea) between 2018 and 2019 by using a trammel net set with a depth range between 5 and 42 m. The sex ratio was found 1:1.08 for males and females, respectively. The length-weight relationship was described for combined both sexes by the following formula W = 0.00130×L3.094 (r2 = 0.918) with a positive allometric growth. Fulton condition factor (CF) was calculated as 1.713 ± 0.145 for combined sexes. This study presents the first results available for the length-weight relationships and condition factor of T. flavimaculosus according to both sexes in the Yumurtalık coast of Turkey.

Composition, size distribution, length-weight relationship of sympatric mud crab species (Scylla) and the case of presumed hybrids

Multiple species of mud crabs are known to co-exist sympatrically within the same ecosystem. However, little is known about the potential factors influencing their community composition. In addition, four types of presumed hybrids (SH 1–4) of the genus Scylla with distinct variations in morphological and morphometric characters were reported recently at Kota Marudu Mangrove Forest, Sabah, Malaysia. Therefore, this study described the species composition and investigated the potential species composition-regulating factors of mud crabs in Kota Marudu Mangrove Forest, Sabah, Malaysia. Further, the size distribution, length-weight relationships, and Fulton's condition factors (Ks) of Scylla species, including S. olivacea, S. tranquebarica, S. paramamosain and presumed hybrid SH 1 were also estimated and compared. Interchanging distribution patterns were observed between the two dominating species – S. paramamosain and S. tranquebarica. Interestingly, all four presumed hybrids were only found in September and October 2012. Poisson regression showed that species, sex, and sampling period were influencing factors of Scylla's composition variation. In terms of size, S. tranquebarica was the heaviest and the largest amongst other species. Based on their length-weight relationships, females exhibited negative allometry whereas males showed positive allometry, except S. olivacea males due to their low sampling size. The K values were similar among species and sexes, except S. tranquebarica females with significantly lower mean K values. The results of this study contribute towards the understanding of the relationship between sympatric Scylla species and provide a basis for future hybrid confirmation studies. The description of length-weight relationships and K values of each Scylla species and group serves as essential baseline data for future fisheries management.