Journal of Fisheries (University of Rajshahi)
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Population dynamics of bearded croaker Johnius dussumieri (Cuvier, 1830) from Pakistani waters
Get PDFIn this study the length frequency data of 2510 bearded croaker Johnius dussumieri (Cuvier, 1830), collected from the coast of Pakistan during 2015, were analysed. Total length of the specimens (male and female combined) varied from 4 to 25 cm with dominant individuals ranged between 12 and 15 cm whereas the body weight varied between 3 and 155 g. The length frequency data were analysed for the estimation of population dynamics and the power coefficient b of length weight relationship was estimated as 2.83. Other measurements were as follows: asymptotic length, L∞ = 26.25 cm; growth coefficient, K = 1.00 year–1; total mortality, Z = 2.43 year–1; and natural mortality, M = 1.82 year–1. The fishing mortality (F) and exploitation ratio (E) were 0.61 year–1 and 0.251 respectively. The Biological Reference Points (BRPs) with Gulland method for this fishery (Fopt) was estimated 1.82 year–1 which is higher than current fish mortality. Therefore the present study shows that the J. dussumieri fishery is safe in Pakistan
Prevalence of white spot virus and monodon baculovirus in shrimp culture systems of West Bengal, India
Get PDFThe global shrimp aquaculture is impacted by episodes of viral diseases resulting in huge income losses. This communication presents the results of the polymerase chain reaction (PCR) based surveillance of white spot virus (WSV) and monodon baculovirus (MBV) in shrimp culture systems of West Bengal, India. The WSV was detected in 14.87% of the total samples (N = 121) by first PCR and 16.53% of samples by nested PCR. The WSV infection was noticed in 12 of 65 Penaeus monodon, 6 of 39 Litopenaeus vannamei and 2 of 11 Macrobrachium rosenbergii samples. The MBV was detected in 8 of 65 P. monodon samples by non-nested PCR and all were also positive for WSV, thus indicating concurrent infection of shrimp. The results emphasized the need to observe strict quarantine measures during the seed selection to prevent the introduction of viral pathogens in grow-out systems
Delineation of seven species of genus Channa from upper Assam region, India using sagittal otolith morphology
Get PDFMorphology of sagittal otoliths of seven species of genus Channa from upper Assam, India was studied to obtain baseline information for their prospective role in taxonomic studies. In the present study, variations were recorded in morphological characteristics of sagittal otolith among the studied species. Of all the studied parameters, otolith shape, sulcus acusticus, ostium, and cauda, in particular, were found to be taxonomically important features for the identification of the species. The pentagonal shape of sagitta in Channa punctata, pseudo-ostiocaudal sulcus acusticus in C. marulius, bent concave ostium in C. stewartii, straight cauda in C. bleheri were found to be species-specific features. Sagitta size was smallest in C. gachua while the largest was recorded in C. striata. The proposed taxonomic keys enumerated through the combination of different otolith characters from the present investigation will be useful in the identification of these species when standard methodologies fail to deliver satisfactory results
Meristic and morphometric characteristics of the Black Sea salmon, Salmo labrax Pallas, 1814 culture line: an endemic species for Eastern Black Sea
Get PDFThe Black Sea salmon Salmo labrax Pallas, 1814 is an essential species for the Turkish aquaculture sector, given increasing trends of the annual productions. To date, there are few studies on meristic and morphometric characteristics of this species. In this study, the fifth filial generation of the species was specified and studied for meristic and morphometric characteristics. The results obtained in this study were compared with available literature and a similarity was found between the study specimens and wild individuals. The morphological characteristics of any cultured species is valuable especially when a new culture generation is formed and therefore this study outcomes may provide important information to the literature
Fish stock demographics of skipjack tuna (Katsuwonus pelamis) from Kavaratti in Lakshadweep, Southern Arabian Sea
Get PDFMarine fish stocks are depleting at an alarming rate. Skipjack tuna, Katsuwonus pelamis has been exploited in Lakshadweep Island area in the Indian Ocean mainly by pole and line fishery which constituted one-third of its production in the country. Age, growth, demographics and stock assessment of this species were investigated from the Lakshadweep waters. The von Bertalanffy growth factors were estimated as asymptotic length 72.5 cm, growth constant 0.480 and the theoretical age at zero-length as –0.1097. This study showed that skipjack grows from 30 to 68.26 cm from first to sixth year. The natural mortality, fishing mortality and total mortality were 0.82, 1.51 and 2.33 respectively. The exploitation ratio was 0.65, while the exploitation which maximises relative yield per recruit (Emax) was 1.0. Recruitment pattern showed that young recruits entered the fishing grounds in most months, with peaks during June–July. Length based Virtual Population Analysis indicated that the major loss in its stock up to 22 cm was due to natural causes. At the same time, higher fishing mortality was registered in 40–60 cm length group. The present study provides knowledge on the demographics of K. pelamis, pertinent for formulating an effective fisheries management in the region
The stock status of the pelagic fishes in Banyuasin coastal waters, Indonesia
Get PDFInformation on the condition of pelagic fish stocks in Banyuasin coastal waters is currently very limited. This study aimed to estimate the stock status of Auxis spp., Scomberomorus commerson, Selaroides leptolepis and Rastrelliger spp. based on the time series catch and effort data from 2008 to 2016 in the Banyuasin coastal waters, South Sumatra Province, Indonesia. All seven surplus production models, model performance, and fish stocks status were estimated. In order to determine the best-fitted model, several indicators of model performance were required. The Pella and Tomlinson model was the best-fitted model for S. commerson while the best-fitted model for Rastrelliger spp., Auxis spp. and S. leptolepis was the Fox model. The optimum effort (EMSY) value for S. commerson, Rastrelliger spp., Auxis spp. and S. leptolepis were 68677, 18226, 23402 and 22403 trips respectively. The maximum sustainable catch (CMSY) value for S. commerson, Rastrelliger spp., Auxis spp. and S. leptolepis were 1845, 515, 286, 667 tons respectively. In 2016 the stock of S. commerson was in recovery condition whereas it was subjected to overfishing for Auxis spp. and depleted for S. leptolepis and Rastrelliger spp
New record of parasitic isopod (Isopoda: Bopyridae) infecting the branchial chamber of blue swimming crab Portunus pelagicus (Linnaeus, 1758) (Decapoda: Portunidae) in the Philippines
Get PDFA parasitic disease causing swollen carapace in commercially important blue swimming crab (Portunus pelagicus L.) has not received considerable attention; neither its causative agent is identified nor its seasonality is recorded. This study aimed to identify the parasite in P. pelagicus inhabiting the Manila Bay. Parasite found in the branchial chamber were isolated, preserved in ethanol and examined. A total of 292 crab specimens were examined and ten were found to be infected (3.42% prevalence with 0–2 parasites per host). Infections were only observed in November 2014 and between January and June 2015. The highest prevalence of infection (10.34%) was recorded in January 2015 whereas the greatest intensity of infection (up to two parasites per infected crab individual) was recorded from February to April 2015. The parasite, based on morphology, was identified as Allokepon monodi. This study presents the third record of female and second record of male A. monodi infecting a crab species. It also represents the first record of male A. monodi in P. pelagicus and in the Philippines. We recommend further studies on the impacts and economic implications of the disease
Seasonal variation of cladocera in a perennial pond, Ambajogai (Maharashtra), India
Get PDFA systematic investigation on seasonal variations of cladocera in Udayan Sarovar, a perennial pond near Swami Ramanand Teerth Mahavidyalaya at Ambajogai (Maharashtra, India) was carried out for a period of one year from June 2018 to May 2019. A total of 9 species of cladocera were identified. The cladoceran diversity fluctuated seasonally and the maximum number of 240 organisms L–1 was recorded during month of April and minimum number of 22 organisms L–1 during the month of September
Quality and shelf life of vacuum- and nitrogen-packed dried barb fish (Puntius spp.)
Get PDFVacuum and modified atmosphere packaging are widely used for preserving food items including fish. In this context, the quality and shelf life of air- (control), vacuum- and nitrogen-packed dried barb fish (Puntius spp.) stored at ambient temperature were evaluated through biochemical and microbial analyses for 90 days. In most of the storage days, significantly lower values of moisture, total volatile base-nitrogen (TVB-N) and peroxide value (PV) were observed in the vacuum pack sample compared to control. However, the TVB-N, PV, total coliforms and faecal coliforms counts were within the acceptable limit in all groups. The total plate count (TPC) increased gradually with time from an initial value of 4.29 log CFUg–1. However, compared to control, significantly lower TPC were found on and after the 30th day of storage in vacuum and nitrogen pack samples. Considering the TPC value of 5 log CFUg–1, the shelf life was determined at approximately 15 days for control, 35 days for nitrogen pack and 45 days for vacuum pack samples. Therefore, the vacuum pack is considered the best packaging, which may be utilised by the processors to produce and retail the dried products with prolonged shelf life
Age, length-weight relationships and condition factors of endemic Antalya barb Capoeta antalyensis (Battalgil, 1943)
Get PDFThe aim of this study was to determine the length-weight, length-length relationships (LWR and LLR) and condition factors of Antalya barb Capoeta antalyensis, an endemic species to Turkey. The specimens (N = 125) were caught using the gill nets in the Sorgun Dam (Aksu, Isparta). The age of the study specimens varied between one and six years. The total length and body weight of the specimens varied from 17.7 – 36.7 cm and 57.03 – 526.91 g respectively. A negative allometric growth (b = 2.7743) was recorded for the species whereas the LWR and total length (TL) – fork length (FL) equations were W = 0.0203 × TL2.7743 (R2 = 0.95) and TL = 0.402 + FL × 1.061 (R2 = 0.99) respectively. The condition factor was determined for every specimen. In light of the results obtained in the study this species may be considered for aquaculture ensuring sustainable population in the wild. This study provides new information that can play an important role in the sustainable management this species