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Reproductive dynamics of commercially important penaeid prawn Penaeus merguiensis was investigated in the coastal waters of Maharashtra during 2002-2003 by collecting data from inshore nearshore and offshore, waters. The size at maturity was 123 mm for males and 133 mm for females. The species spawned throughout the year with two spawning peaks, major one during March-May and minor during October-December and spawning area of the species is offshore waters >40 m depth. Ova diameter study showed tendency to shed all their eggs at one instance, but the progression of modal sizes of mature females demonstrated that females with spawning periodicity of 26±5.5 days could spawn about 12 times during their life span. The sex ratio showed that mainly large sized mature females migrate towards offshore deeper waters. Fecundity was exponentially related to length by F= 0.000000528*TL5.2086. The population fecundity index in nearshore and offshore areas indicated two peaks with major spawning activity during March-April and minor during August-September. The egg production by the surviving population in the sea, gave major peak during April-May and a minor during November. The occurrence of juveniles in the catch was bimodal and their mean size declined twice in inshore, nearshore and offshore waters which pointed to two recruitment pulses in March and November in inshore waters and in March and December in nearshore and offshore waters. The percentage of juveniles was the highest in March which suggested that post-monsoon spawning in November was the most effective. The ratio of juveniles and the egg production gave annual survival rate of 0.03%. The monthly survival showed bimodal trend with peak in April (0.07%) and November (0.03%), which suggested that spawning during November-December and May-June was responsible for the two cohorts, the post-monsoon and pre-monsoon, among which the former was more successful. [ABSTRACT FROM AUTHOR]

The banana prawn (Fenneropenaeus merguiensis) is a valuable prawn in the worldwide market. However, cultivation of this species is limited owing to the difficulty in culture management and limited knowledge of reproduction. Therefore, we studied the gene expression and molecular mechanisms involved in oogenesis for elucidating ovarian germ cell development in banana prawns. The tissue-specific distribution of certain genes identified from previous transcriptome data showed that FmCyclinB, FmNanos, and nuclear autoantigenic sperm protein (FmNASP) were only expressed in gonads. The in situ hybridization (ISH) of these three genes showed different expression patterns throughout oogenesis. FmCyclinB was highly expressed in pre-vitellogenic oocytes. FmNanos was expressed at almost the same level during oogenesis but showed the most expression in late pre-vitellogenic stages. Based on the highest expression of FmCyclinB and FmNanos in mid pre-vitellogenic and late pre-vitellogenic oocytes, respectively, we suggested that FmNanos may suppress FmCyclinB expression before initiation of vitellogenesis. Meanwhile, FmNASP expression was detected only in pre-vitellogenesis. Moreover, quantitative real-time polymerase chain reaction (qRT-PCR) analysis of FmNASP expression was supported by FmNASP ISH analysis based on high expression of FmNASP in sub-adult ovaries, which contain most of pre-vitellogenic oocytes. In this study, we found three reliable ovarian markers for banana prawns and also found a dynamic change of molecular mechanism during the sub-stage of pre-vitellogenesis. We determined the expression levels of these genes involved in oogenesis. Our findings provide information for further studies on banana prawn reproduction which may assist in their cultivation.

The high market demand for banana prawn (P. merguiensis) has caused intensive fishing for this resources and tended to threaten their sustainability. Studies of population dynamics and spawning potential ratio are the main foundations for formulating a management for sustainable utilization. The purpose of this study was to determine the population dynamic and spawning potential ratio of banana prawn in Merauke waters, Papua. The study was conducted from 2017 to 2019 using a survey method. The study results revealed that the banana growth pattern was negative allometric and that the ratio of males and females was imbalanced. The spawning season of banana prawn in Merauke waters occurs throughout the year with one peak in August. Based on carapace length measurement, length at first capture (Lc) and length at first maturity (Lm) were 33.5 mm and 32.7 mm respectively. While growth rate (K) and maximum carapace length (Lâ?ž) valued 1.25 per year and 64.85 mm respectively. The estimate total mortality rate (Z) was 3.20 per year, the fishing mortality rate (F) and natural mortality rate (M) were 1.7 per year and 1.49 per year, respectively. The exploitation rate (E) was 0.53 per year and the spawning potential ratio (SPR) was 15 %. Therefore the stock status was categorized as overfishing. In order to ensure the sustainability of the banana prawn, precautionary approach such as reducing fishing effort by 6 % of the current situation is strongly needed to be applied. [ABSTRACT FROM AUTHOR]

Changes in tropomyosin derived antigenicity of banana prawn (Fenneropenaeus merguiensis) due to high pressure processing (HPP) at 600 MPa for 5 or 10 min at various temperatures (40, 80, 120 °C) were investigated. HPP of prawn samples at 40 and 80 °C for 5 min increased tropomyosin derived antigenicity by almost double, whereas HPP at 120 °C for 10 min decreased antigenicity by 65%, detected using ELISA kit. A significant (P ≤ 0.05) reduction of tropomyosin antigenicity after pepsin digestion was noticeable in prawns after HPP, but not in control prawn sample. However, further digestion of the control and HPP sample with pancreatin enzyme decreased antigenicity to ∼0 mg mL-1. The combination of HPP and high temperature (120 °C) in the current study can potentially reduce tropomyosin-derived antigenicity in whole prawn muscle, whereas SIF digestion with pancreatin enzyme may present a new prospective method to produce hypo-antigenic, enzymatically digested prawn products. • HPP of prawn for 10 min at 120 °C decreases tropomyosin antigenicity by 65%. • HPP (600 MPa) of prawn at 40 and 80 °C increases antigenicity by almost double. • Pepsin enzyme digestion significantly reduces antigenicity in HPP prawn samples. • No significant effect of pepsin enzyme on untreated prawn antigenicity. • Further digestion with pancreatin reduces tropomyosin antigenicity to ∼0 mg mL-1. [ABSTRACT FROM AUTHOR]

Summary: Different processing techniques were assessed to attenuate the antigenicity of banana prawn tropomyosin (Fenneropenaeus merguiensis). Frying and boiling at different temperatures, acid treatment using different acids and storage at −20 °C up to 3 months were investigated. Untreated prawn sample was used as a control. Frying significantly increased antigenicity (6–8 times) in temperature‐dependent manner, whereas the trend was fundamentally reversed with boiling. Boiling at 121 °C resulted in the lowest antigenicity (12.99 mg mL−1) among all heat‐treated samples, yet higher than the control (5.06 mg mL−1). Freezing had initially very minor impact, although prolonged storage at −20 °C increased antigenicity slightly (2.29 mg mL−1) compared with control. Antigenicity was impacted the most by a reduction in pH independent on the type of acid as both acetic and HCl acids significantly reduced antigenicity of tropomyosin by ~90% compared with control. This could be considered as a new approach to processing that may potentially reduce tropomyosin‐derived antigenicity in prawns and prawn products. This study also confirmed the actual molecular weight of banana prawn tropomyosin was 37 kDa implementing a new methodology using unstained gel. Effects of selected processing treatments on antigenicity of banana prawn (Fenneropenaeus merguiensis) tropomyosin. [ABSTRACT FROM AUTHOR]

This research was carried out in Strait of Hormuz in 2020. The present study aimed to investigate the migration and growth pattern of tagged shrimps in the study area. Bloodstock shrimps were reared in June (2010). About 50000 juvenile shrimps were tagged by red color florescent elastomeric tag and released in the estuaries of Tiab, Kolahi and Koolgan at night in July 2010. Local people were informed through posters describing the tagging program, as well as articles published in a local magazine. A tagging program film was broadcasted on local television three times prior to the shrimp fishing season and during shrimp catch period. In the catch season, September and November months, 11 tagged prawns (0.022%) were recaptured. Movement direction of tagged prawns was northwesterly of deeper waters of releasing areas. Speed was recorded at 0.33-0.33 km/day and tagged prawns were recaptured 46 km from the released locations. The mean (±SD) weight of released banana prawns and the average weight of the recaptured prawns were1.2±0.2 g and 22.06±4.9 g, respectively. The growth rate of recaptured prawns was 16-26 g and growth speed was 0.88-1.41 g per week. In the study area, the major sea current was from the Oman Sea to the Persian Gulf through Strait of Hormuz probably influencing the pattern of banana prawn movement in Hormozgan

The banana prawn ( Fenneropenaeus merguiensis ) is a valuable prawn in the worldwide market. However, cultivation of this species is limited owing to the difficulty in culture management and limited knowledge of reproduction. Therefore, we studied the gene expression and molecular mechanisms involved in oogenesis for elucidating ovarian germ cell development in banana prawns. The tissue-specific distribution of certain genes identified from previous transcriptome data showed that FmCyclinB , FmNanos , and nuclear autoantigenic sperm protein ( FmNASP ) were only expressed in gonads. The in situ hybridization (ISH) of these three genes showed different expression patterns throughout oogenesis. FmCyclinB was highly expressed in pre-vitellogenic oocytes. FmNanos was expressed at almost the same level during oogenesis but showed the most expression in late pre-vitellogenic stages. Based on the highest expression of FmCyclinB and FmNanos in mid pre-vitellogenic and late pre-vitellogenic oocytes, respectively, we suggested that FmNanos may suppress FmCyclinB expression before initiation of vitellogenesis. Meanwhile, FmNASP expression was detected only in pre-vitellogenesis. Moreover, quantitative real-time polymerase chain reaction (qRT-PCR) analysis of FmNASP expression was supported by F mNASP ISH analysis based on high expression of FmNASP in sub-adult ovaries, which contain most of pre-vitellogenic oocytes. In this study, we found three reliable ovarian markers for banana prawns and also found a dynamic change of molecular mechanism during the sub-stage of pre-vitellogenesis. We determined the expression levels of these genes involved in oogenesis. Our findings provide information for further studies on banana prawn reproduction which may assist in their cultivation.

A major decline in the catch of the banana prawn [shrimp], Penaeus (Fenneropenaeus) merguiensis, occurred over a six-year period in the Weipa region of the northeastern Gulf of Carpentaria, Australia. Three main hypotheses have been developed to explain this decline: (1) prawn recruitment collapsed due to overfishing; (2) recruitment collapsed due to a change in the prawn's environment; and (3) adult banana prawns were still present, but fishers could no longer effectively find or catch them. Qualitative mathematical models were used to link population biology, environmental factors, and fishery dynamics to evaluate the alternative hypotheses. This modeling approach provides the means to rapidly integrate knowledge across disciplines and consider alternative hypotheses about how the structure and function of an ecosystem affects its dynamics. Alternative models were constructed to address the different hypotheses and also to encompass a diversity of opinion about the underlying dynamics of the system. Key findings from these analyses are that: instability in the system can arise when discarded fishery bycatch supports relatively high predation pressure; system stability can be enhanced by management of fishing effort or stock catchability; catch per unit effort is not necessarily a reliable indicator of stock abundance; a change in early-season rainfall should affect all stages in the banana prawn's life cycle; and a reduced catch in the Weipa region can create and reinforce a shift in fishing effort away from Weipa. Results from the models informed an approach to test the hypotheses (i.e., an experimental fishing program), and promoted understanding of the system among researchers, management agencies, and industry. The analytical tools developed in this work to address stages of a prawn life cycle and fishery dynamics are generally applicable to any exploited natural resource. [ABSTRACT FROM AUTHOR]