Penaeus Semisulcatus Research Articles

Morphometric relationships and condition factor of the green tiger shrimp, Penaeus semisulcatus De Haan, 1844 (Decapoda, Penaeidae), from Palk Bay waters of Tamil Nadu

Abstract Morphometric relationships and condition factors are essential for understanding any marine species’ development process, which aids in designing appropriate strategies for management and articulating their balance in the ecosystem — and this includes shrimps. Since only a few studies on these characteristics have been done in Penaeus semisulcatus over the last thirty years, constant updating of these criteria is required to successfully manage the shrimp fishery in Palk Bay. The CL-TW relationship demonstrates negative allometric growth in both males and females, whereas the TL-TW relationship exhibits positive allometric growth. In this present investigation, significant differences in slopes and elevations of the carapace length-total weight, total length-total weight, carapace length-total length, and total length-carapace length have been observed between sexes; considering the condition factors shown in the present investigation, the shrimps in Palk Bay were in good growing condition. This study has demonstrated that updated information on morphometric relationships would help fishery managers effectively manage the fisheries.

Comparative morphological analysis of telson and uropods in Penaeus canaliculatus (Olivier, 1811), Penaeus semisulcatus (De Haan, 1844), and Metapenaeus stebbingi (Nobili, 1904) using scanning electron microscopy and EDX analysis

The telson and uropods collectively form the tail fan, playing crucial roles in locomotion, buoyancy, defense, and respiration. We aimed to compare telson and uropod structures in three shrimp species—Penaeus canaliculatus, Penaeus semisulcatus, and Metapenaeus stebbingi—to identify the species with the most robust telson for its environment. Our analysis involved morphological measurements and scanning electron microscopy (SEM), supplemented by a novel approach—Energy-Dispersive X-ray (EDX) spectroscopy, a technique not previously utilized in studies on these three species. M. stebbingi exhibited the longest telson length, whereas P. semisulcatus had the longest uropod. P. canaliculatus featured a single pair of fixed spines, while P. semisulcatus had evenly spaced small conical spines along the sides of the median elevation and groove. A distinctive feature of M. stebbingi was the telson, which had three pairs of large spines. Diverse setae on telsons included simple, unipennate, and plumose setae. Notably, specialized branched tubular setae on uropods' endopods may aid in grooming or swimming behavior. EDX spectroscopy revealed that the telson cuticle primarily consists of carbon, nitrogen, and oxygen, with significantly high concentrations alongside comparatively lower calcium and phosphorous concentrations. P. semisulcatus exhibited the highest calcium and phosphorus content among the three species. In conclusion, M. stebbingi's telson is structurally robust, emphasizing the importance of morphology, while P. semisulcatus demonstrated a hard telson through EDX analysis. Our study underscores not solely relying on morphology for telson strength assessment but considering telson composition. These variations among species may be attributed to diverse ecological and physiological adaptations.

Length-weight Relationship and Condition Factors of Seven Penaeus Shrimp Species along the Southeast Coast of Tamil Nadu (Southern India)

Background: The present study of the length-weight relationship and condition factors of seven shrimp species on the southeast coast of Tamil Nadu between July (2022) and February (2023) also estimated the coefficient of determination (r2). Methods: For shrimp species, the length-weight relationship shows some species have significant positive coefficients which have a determination by (r2 greater than 0.5) like Penaeus indicus, Penaeus mergiuensis, Penaeus canaliculatus, Penaeus latisulcatus, Penaeus monodon, some species have shown negative as (r2 greater than 0.5) value like Penaeus japonicas and Penaeus semisulcatus. Result: All shrimp species have heterogeneity evident in intercept (a). The growth exponent (b) varied between 0.278 and 2.289 and it significantly (p=0.05) deviated from the value of less than 3 which denoted negative allometric growth for all Penaeus shrimp species.

Study of adsorption isotherms and kinetic models for lead (II) in the mining pit water at Bangka on shrimp waste chitosan

The isotherms and kinetic adsorption models for lead (II) in the mining pit water at Bangka on Shrimp Shells Waste Chitosan (Sw-Chi) was studied. The Sw-Chi from the dried shrimp (generally Penaeus semisulcatus species) waste were extracted via deproteinization, demineralization, decolorization and deacetylation steps at previous work. The chitin deacetylation values of Sw-Chi was 88.98% determined through FTIR spectra using baseline method. The initial lead (Pb (II)) concentration in this study was 0.41 ppm from open-pit water in Sungailiat district, Bangka Island. The performance of Sw-Chi adsorption on lead in the pit water with the ratio of 1:500 (w/v) in variation contact time while stirring at room temperature. The adsorption isotherms and kinetic models for lead in the mining pit water at Bangka follows the pseudo-second-order (PSO) and the Freundlich isotherm (F-Isoth) model. The adsorption mechanism may be due to Van der Waals forces and formed lead multilayer onto Sw-Chi surfaces.

CeO2-CePO4 and Ag@CeO2-CePO4 nanocomposites from Penaeus semisulcatus for heavy metals sensing, UV shielding and cytotoxic applications

CeO2-CePO4 and Ag@CeO2-CePO4 nanocomposites (NCs) were prepared using Penaeus semisulcatus and characterized by various analytical techniques. The NCs exhibited spherical morphology, with average particle sizes measuring 2.36 nm, 3.30 nm and 29.64 nm for the samples air dried, annealed at 550 °C and 800 °C respectively, and the Selected Area Electron Diffraction patterns from HR-TEM revealed their crystalline nature. In 3d X-ray Photoelectron Spectra (XPS) of NCs, the highest binding energies were observed at 916.46 eV (3d3/2) and 898.16 eV (3d5/2) with spin–orbit splitting of 18.3 eV. The X-Ray Diffraction (XRD) patterns of the NCs showed peaks typical of both CeO2 and CePO4 phases. The Fourier Transform-Infra Red (FT-IR) spectrum contained bands due to Ce-O stretching at 560 cm−1 and PO43- groups at 1008 and 711 cm−1, which was further substantiated by Raman spectrum, which had an intense peak at 468 cm−1 corresponding to F2g band of CeO2 and another peak at 976 cm−1 due to PO43- tetrahedron. In the Ultraviolet-Visible Diffuse Reflectance Spectra (UV-Vis DRS), the broad absorption peak at 352 nm and minor peaks around 300 nm confirmed the formation of CeO2-CePO4 NCs. The green synthesized NCs were excellent fluorescence sensors for Pb2+, Cd2+ and Hg2+ in a wide range of concentrations, from 5.0x10-9 M to 4.0x10-5 M. The concentration Vs. emission fitting plot had three distinctive linear ranges. At a low concentration range (5x10-9 to 3.5x10-7 M), the limit of detection for Pb2+, Cd2+ and Hg2+ was found to be 2.41x10-8, 2.56x10-8 and 3.11x10-8 M. The sensitive detection of a mixture of heavy metal ions in ppb levels by biocompatible NCs gained insight in treating aqueous industrial wastes. Further, NCs showed cytotoxicity and UV shielding properties.

The effects of two different net modifications on reducing discards in the trammel net fishery for prawn in Mersin Bay

The discarded species caught in prawn trammel nets damage the nets and cause a serious labor loss problem for fishers. In the present study, a 15 cm high greenhouse plastic film and a greenhouse shade cloth net were fitted between the lower parts of the nets and the lead collars to reduce discards in the trammel net fishery. The modified nets were tested in Mersin Bay with twenty-one fishing operations between September and December 2021. The results showed that, compared to commercial trammel nets, the nets equipped with greenhouse plastic film and greenhouse shade cloth did not significantly reduce the catch of the target species green tiger prawn (Penaeus semisulcatus). However, the total number of discards significantly decreased. The discard rates in the commercial net, greenhouse plastic film net, and greenhouse shade cloth net were 45%, 26%, and 22%, respectively. Furthermore, when the incomes from the nets’ hauls were calculated, the net equipped with greenhouse garden film and the net equipped with greenhouse shade cloth generated 24.77% and 14.41% more profit than the commercial net, respectively.

Relationship fecundity – morphometrics in the green tiger shrimp, Penaeus semisulcatus De Haan, 1844 (Decapoda, Penaeidae), along the Palk Bay, southern Peninsular India

Abstract The green tiger shrimp, Penaeus semisulcatus, is a commercial species supporting important fishery along the Palk Bay coasts. It is a much sought-after seafood commodity influencing the livelihood of the local fishers. This study aims to investigate the fecundity of the species in relation to its morphometry. Fecundity is an index of reproductive capacity used to calculate a stock’s reproductive potential and the egg’s survival. The absolute fecundity of the shrimp ranged from 26 100 to 750 000 ova alive per female, and the mean absolute fecundity from 59 100 to 583 000 ova alive per female. The relationship between fecundity and the morphometric measurements showed a positive exponential correlation. One-way ANOVA indicated a significant difference in the different size classes’ carapace length, total weight, ovary weight, absolute fecundity, stomach weight, and gastrosomatic index. There was no significant difference between the relative fecundity and the gonadosomatic index. This study provides insight into the reproductive potential of P. semisulcatus for efficient management of the resource in Palk Bay, Tamil Nadu, India.

Reproductive biology of green tiger shrimp Penaeus semisulcatus De Haan, 1844 in Palk Bay, southeast coast of India

Penaeus semisulcatus forms a single-species fishery of significant importance along Palk Bay’s southeast coast of India. The reproductive biology of the species was studied from the region as parameters like ovary development, maturity stages, and the spawning season are necessary for better management of the resources. The male testis of P. semisulcatus has eight testicular lobes with oval-shaped ampoules. Chromatin oocytes in immature females, cortical oocytes in mature females, and Atreatic oocytes in mature females were observed. The dark green (or greenish brown) ovary with elongated cortical bodies in the periphery of the ova is fully mature. The spawning season is most active in the post-monsoon and monsoon, with a minor peak in the pre-monsoon. The Lm50 determined was extremely low when compared to other studies conducted on the species, which is attributed to fishing pressure. Males mature earlier than females, and they do not have specific seasons or cyclic changes. The female-to-male ratio was not equal, and females were always found in greater numbers. Beyond 3 Nautical Miles (NM), the entire Palk Bay is designated as a spawning ground, while up to 3 NM, is designated as a nursery ground. These species can be harvested sustainably by imposing a seasonal ban on shrimp fishing during the peak breeding season, regardless of gear.

Effects of the Alga Aurantiochytrium mangrovei FIKU008-Enriched Artemia on Early Stages of the Green Tiger Shrimp, Penaeus semisulcatus

The first aim of the present study was to determine appropriate artemia enrichment levels by using Aurantiochytrium mangrovei FIKU008 served as DHA enrichment source and secondly to test the effects of enriched-Artemia on growth and survival during the early larval stages(M1-PL7) of Penaeus semisulcatus. In the 1st experiment, four different enrichment levels of AUR (0.0,0.6,0.8 and 1.0g/L) against a control commercial solution (S-presso) were tested for 12/24-hours enrichment while in the 2nd experiment, three levels (0.0, 0.6 and 0.8g/L) of AUR enriched-Artemia were fed to larval stages. At the end of both enrichments, DHA and EPA levels were found to be significantly enhanced by using AUR at 0.6 and 0.8g/L. In the 2nd experiment, fatty acid composition of the PL was significantly affected by AUR and the PL fed with enriched diets showed higher n-3 LC-PUFA accumulation in their tissues. The larvae grown from M1 to PL7 displayed higher survivals and growth in the enriched AUR-groups compared to the control(0.0AUR). In conclusion, this study has demonstrated that the use of AUR as enrichment significantly elevated EPA and DHA levels to 0.6-0.8g/L enrichment periods and the enriched-Artemia at such levels were proven to effectively improve growth and survival of the early larval stages of P. semisulcatus.

Occurrence and Characteristics of Microplastics in Wild and Farmed Shrimps Collected from Cau Hai Lagoon, Central Vietnam.

This study investigated the occurrence of microplastics (MPs) in the gastrointestinal tracts (GT) and tissues of four common shrimps (including two wild-caught shrimps and two farmed shrimps) collected from a high-diversity lagoon in central Vietnam. The numbers of MP items in greasy-back shrimp (Metapenaeus ensis), green tiger shrimp (Penaeus semisulcatus), white-leg shrimp (Litopenaeus vannamei), and giant tiger shrimp (Penaeus monodon), determined per weight and individual, were 0.7 ± 0.3, 0.6 ± 0.2, 1.1 ± 0.4, and 0.5 ± 0.3 (items/g-ww), and 2.5 ± 0.5, 2.3 ± 0.7, 8.6 ± 3.5, 7.7 ± 3.5 (items/individual), respectively. The concentration of microplastics in the GT samples was significantly higher than that in the tissue samples (p < 0.05). The number of microplastics in the farmed shrimp (white-leg shrimp and black tiger shrimp) was statistically significantly higher than the number of microplastics in the wild-caught shrimp (greasy-back and green tiger shrimps) (p <0.05). Fibers and fragments were the dominant shapes of the MPs, followed by pellets, and these accounted for 42-69%, 22-57%, and 0-27% of the total microplastics, respectively. The chemical compositions determined using FTIR confirmed six polymers, in which rayon was the most abundant polymer, accounting for 61.9% of the MPs found, followed by polyamide (10.5%), PET (6.7%), polyethylene (5.7%), polyacrylic (5.8%), and polystyrene (3.8%). As the first investigation on the MPs in shrimps from Cau Hai Lagoon, central Vietnam, this study provides useful information on the occurrences and characteristics of the microplastics in the gastrointestinal tracts and tissues of four shrimp species that live in different living conditions.

ANALISIS KUARTIL, DESIL DAN PERSENTIL PADA UKURAN PANJANG UDANG FLOWER (Penaeus Semisulcatus) DI PERAIRAN SAMBOJA KABUPATEN KUTAI KARTANEGARA

Green Tiger Prawn is one of the Prawn from the Penaeidea family and is one the catches caught in the waters of Samboja. This research conducted in October-December 2021 in the waters of Samboja, Kutai Kartanegara catching prawn at night using trawls. The sample used was 129 green tiger prawn with 90 females and 39 males. This study aims to determine the location of quartiles, deciles and persentiles in prawn data assisted by microsoft Excel software and presented in the form of histogram. The results of this study found that the location of the Q1 quartile was 25%, Q2 was 50% and Q3 was 75%. Decile D1 is 10%, D2 is 20% and D3 is 30%. Percentile P25 is 25%, P50 is 50%, dan P90 is 90%.

Influence of different feeding rates of polychaete worms, Eulalia viridis (Annelida, Polychaeta), on the gonad development of male Penaeus semisulcatus (Decapoda, Dendrobranchiata) under captive conditions

Abstract Penaeus semisulcatus is a large growing species, attaining a maximum size of about 250 mm in total length. It is more resistant to white spot syndrome virus (WSSV) than other cultivable penaeid shrimps, which makes it a potential candidate for culture. The present study evaluated the influence of a different feeding rate of polychaete worms on the gonad development of male P. semisulcatus under captive conditions. P. semisulcatus sub-adults were obtained in the wild. The shrimps were fed with three different concentrations of polychaete worms, viz., ad libitum (T1), 5% of body weight (BW) (T2) and 10% BW (T3), and fresh sardines were fed as a Control (C) diet, all for a period of 60 days. Sampling was done once in 15 days and the bio-growth parameters were recorded. The gonads were harvested for histological analysis. The maximum weight gain (10.19 g), mean weight gain percentage (85.20%), mean daily growth rate (DGR) (0.169833) and mean specific growth rate (SGR) (0.45) were found in shrimps fed with the polychaete worm diet at 5% BW. The estimated bio-growth parameter values were statistically significant when analysed using One way ANOVA (). Histological sections of the testis showed variations in the development of the gonad between the treatments with different feeding rates during the 60 days trials. Indeed in all aspects, the development was higher in shrimps fed with polychaete worms at 5% BW. It can be concluded that feeding polychaete worms at 5% BW created a regime able to improve growth rates, gonad maturation, and quality in the development of the captive male brood stock.

Phenotypic and genotypic characterization of pathogenic Escherichia coli identified in resistance mapping of β-lactam drug-resistant isolates from seafood along Tuticorin coast.

The ubiquity of pathogenic E. coli isolate possessing antimicrobial resistance was investigated in seafood samples procured from major seafood supply chain markets established for export and domestic consumption along Tuticorin coast. Out of 63 seafood samples examined, 29 (46%) were found to be contaminated by pathogenic E. coli harbouring one or more genes of virulent potential. Based on virulome profiling, 9.55% of isolates belonged to enterotoxigenic E. coli (ETEC), 8.08% to enteroaggregative E. coli (EAEC), 7.35% to enterohemorrhagic E. coli (EHEC), 2.20% to enteropathogenic E. coli (EPEC), and 2.20% to uropathogenic E. coli (UPEC). All the 34 virulome positive and haemolytic pathogenic E. coli have been serogrouped as O119, O76, O18, O134, O149, O120, O114, O25, O55, O127, O6, O78, O83, O17 and clinically significant O111, O121, O84, O26, O103, and O104 (non-O157 STEC) serotypes in this study. Multi-drug resistance (MDR) (≥ 3 antibiotic classes/sub-classes) was exhibited in 38.23% of the pathogenic E. coli, and 17.64% were extensive drug resistant (XDR). Extended spectrum of β-lactamase (ESBL) genotypes were confirmed in 32.35% isolates and 20.63% isolates harboured ampC gene. One sample (Penaeus semisulcatus) collected from landing centre (L1) harboured all ESBL genotypes blaCTX-M, blaSHV, blaTEM, and ampC genes. Hierarchical clustering of isolates revealed the separation of ESBL isolates into three clusters and non-ESBL isolates into three clusters based on phenotypic and genotypic variations. Based on dendrogram analysis on antibiotic efficacy pattern, carbapenems and β-lactam inhibitor drugs are the best available treatment for ESBL and non-ESBL infections. This study emphasizes the significance of comprehensive surveillance of pathogenic E. coli serogroups that pose serious threat to public health and compliance of AMR antimicrobial resistant genes in seafood that hinder seafood supply chain.

Stock Status of Green Tiger Prawn (Penaeus semisulcatus de haan, 1844) in Bombana and Adjacent Waters, Southeast Celebes, Indonesia

The high market demand for green tiger prawn (Peneus semisulcatus de Haan) has caused intensive fishing for this resources and tended to threaten their sustainability. Studies of stock status are the main foundations for formulating a management for sustainable utilization. The purpose of this study was to determine the stock status of green tiger prawn in the Bombana and adjacent waters, South-east Celebes. The study was conducted from April to November 2021 using a survey method. The study results revealed that the green tiger prawn growth pattern was negative allometric and that the ratio of males and females was imbalanced. Based on total length measurement, length at first capture (Lc) and length at first mature (Lm) were 37.42 cm and 38.72 mm respectively. While growth rate (K) and maximum total length (L∞) valued 1,7 per year and 58.9 mm respectively. The estimate total mortality rate (Z) was 2.57 per year, the fishing mortality rate (F) and natural mortality rate (M) were 1.12 per year and 1.45 per year, respectively. Recruitment pattern occured throughout the year with one peak in June. The exploitation rate (E) was 0.44 per year, therefore the stock status was categorized as fully exploited. In order to ensure the sustainability of the green tiger prawn, precautionary approach such as increasing fishing effort by 10 % of the current situation is strongly needed to be applied

Essential and Non-Essential Metal Concentrations in Shrimps from Iskenderun Bay, Türkiye

Contamination of the aquatic environment and living things with pollutants is increasing daily. Among these pollutants, heavy metals come to the forefront regarding toxicological and public health due to their widespread use, toxicity, and resistance to degradation, as well as accumulation and biomagnification in the food chain. The study aimed to determine the essential (Cr, Cu, Fe, Mn, Ni, Zn) and non-essential (As, Al, Cd, Pb) metal concentrations by ICP-OES of Metapenaeus monoceros, Penaeus japonicus, Penaeus semisulcatus (n=30) caught from the Northeastern Mediterranean, Iskenderun Bay. The concentration of Cd, Cr, Ni, and Pb were under LOD. The concentration (ppm) ranges were Al: 0.73-38.89, As: 2.18-9.68, Cu: 28.96-69.01, Fe: 7.85-241.36, Mn: 0.44-1.28, and Zn: 51.71-108.51 for all species. Except for the As concentrations, the differences between mean concentrations of metals in shrimp species were not statistically significant. When the results of the study are compared with the findings of other studies on shrimps caught from the Iskenderun Bay, it shows that Cd, Cr, Ni, and Pb contamination levels decreased, while Cu, Fe, and Zn contamination levels increased.

MICROPLASTIC FIBER ACCUMULATION IN SOME WILD AND CULTURED SHRIMP SPECIES

This study was conducted to examine the microplastic fiber abundance and its characteristics in two wild and two cultured shrimp species collected at coastal areas in Hoai Nhon district, Binh Dinh Province. A total of 84 individuals of four shrimp species, Litopenaeus vannamei, Penaeus monodon, Metapenaeus ensis, and Penaeus semisulcatus were collected for analysis. All shrimp specimens were dissected to remove the digestive tracts, which were then treated with 10% KOH to collect microplastic fibers by filtering. The microplastic fiber concentrations varied from 1.96 ± 0.09 to 19.33 ± 10.82 fibers/specimen or 0.20 ± 0.12 to 2.26 ± 1.26 fibers/g of wet body weight. The abundance of fibers in the wild shrimps (Penaeus semisulcatus and Metapenaeus ensis) was higher than in the cultured shrimps (Penaeus monodon and Litopenaeus vannamei). Most fibers observed in the four shrimp species had lengths between 300 and 1500 μm, accounting for 78.72% to 92.82% of the total). White fibers were dominant (30.38%), followed by gray (11.87%), and green (10.60%).

Shrimps distribution and their relationship to the environmental variables in Arafura Sea

Arafura Sea is well-known as the important area for commercial shrimp fisheries in Indonesia. The density of shrimps was highly influenced by their fishing pressure and environmental condition. The objective of this research was to study the distribution of shrimps based on its stock density and their relationship with the environmental variables. Trawling swept area method was used in 16 sampling sites of Arafura Sea during the transition monsoon in 2016. Some environmental variables in bottom layers as shrimp habitat were measured, including chlorophyll-a, dissolved oxygen, depth, salinity, temperature and pH. The results showed that the largest density of shrimps was found in the southern coast of Aru where it has the largest concentration of chlorophyll-a and dissolved oxygen. Among all the environmental variables, Chlorophyll-a was the main variable affected the density of shrimps. Three most dominant species were Penaeus semisulcatus, Metapenaeus endeavouri and Metapenaeus ensis. There was indication of the decreasing shrimp stock in Arafura Sea. The ecosystem-based fisheries management should be developed to rebuild the stock density and to enhance the environmental quality of Arafura Sea.

Improvement the Hatchery Seed Production Strategy on Embryonic Development and Larval Growth Performance and Development stages of Green Tiger Prawn, Penaeus semisulcatus Using Environmental Aspects

This investigation aimed to improve the hatchery seed production strategy in terms of chronologies of embryonic and larval development as well as hatching, growth and survival rates, and rearing water quality of green tiger prawn, Penaeus semisulcatus by the integration effects of different water temperatures (23 °C, 26 °C, 29 °C, 32 °C) and probiotic as water additives. The best and shortest chronologies of embryonic development stages were in favor of 32 °C with probiotic. The best hatching rate was in favor of 29 °C with probiotics. The fastest larval development and greatest larval growth as total length until PL1 stage was promoted by 32 °C with probiotic but the best survival rate was recorded at 26 °C with probiotic followed by 29 °C with probiotic treatment. During larval development, the lowest value of NH4–N was recorded under the effect of 26 °C and probiotic. Therefore, probiotics as water additives at 29 and 32 °C water temperatures have a beneficial impact on the hatchery seed production strategy and quality of P. semisulcatus. Our findings could apply to rearing larvae in shrimp hatchery to decrease the chronology of embryonic and larval development, while increase the hatching rate, growth performance, and survival rates as well as improving the water quality.

Bioprocess of astaxanthin extraction from shrimp waste via the common microorganisms Saccharomyces cerevisiae and Lactobacillus acidophilus in comparison to the chemical method

This study compared microbiological and chemical methods used in astaxanthin extraction from the exoskeleton of the shrimp species Penaeus japonicus and Penaeus semisulcatus. The microbiological method was performed using Saccharomyces cerevisiae (bakery yeast) or Lactobacillus acidophilus (from yogurt), followed by solvent extraction with hexane and acetone at different ratios (1:1, 1:2, and 1:3). The chemical method was performed traditionally using hexane. The highest astaxanthin yield from P. japonicus exoskeleton was obtained using either S. cerevisiae or L. acidophilus followed by solvent extraction with hexane and acetone at a ratio of 1:1 (8.5 and 8.1 mg/g waste, respectively) as well as by the chemical method (8.4 mg/g waste). Likewise, the highest astaxanthin yield from P. semisulcatus exoskeleton was obtained using either S. cerevisiae or L. acidophilus followed by solvent extraction with hexane and acetone at a ratio of 1:1 (3.0 and 4.1 mg/g waste, respectively) as well as by the chemical method (3.2 mg/g waste). The values obtained from P. semisulcatus exoskeleton were considerably lower than those attained from P. japonicus exoskeleton. In addition, the nuclear magnetic resonance (C-NMR) analysis confirmed that astaxanthin was the main carotenoid present in the extract. In conclusion, the pretreatment of exoskeleton wastes of P. japonicus using S. cerevisiae followed by solvent extraction with hexane and acetone at a ratio of 1:1 as well as the classical chemical treatment led to the highest astaxanthin content.

Population dynamics of two morphotypes ofgreen tiger shrimp Penaeus semisulcatus de Haan, 1844 in the northern coast of Iran

Population biology of two morphotypes of Penaeus semisulcatus de Haan, 1844 was investigated from January to July 2017 and January 2018 to December 2019 in the Hormozgan coastal waters off Iran. Growth in both sexes was negative allometric. The sex ratio (M:F) was significantly different in terms of month and length classes in both the morphotypes. Year round the female population dominated in the banded morphotype while males in the non-banded morphotype. Size-wise, the male population was more in smaller classes and females in larger classes for both the morphotypes. The spawning peak of shrimps occurred in spring season (from March to May) and in winter-spring (from January to May) for banded and non-banded morphotypes, respectively. The Lm50% for banded and non-banded shrimp was estimated at a carapace length of 37.86 and 43.43 mm, respectively. The K and CL∞ in banded shrimp were 1.6 y-1 and 46 mm for males and 1.8 y-1 and 57 mm for females and in non-banded shrimps were 1.7 y-1 and 55 mm and 2.1 Y-1 and 69 mm for males and females, respectively. The total mortality (Z) and fishing mortality (F) estimated in males were more than in females. The evidence showed that these are probably two different species in the region. Keywords: Growth and mortality, Oman Sea, Penaeus semisulcatus, Persian Gulf, Reproductive biology, Size structure