scholarly journals TIPE PERIKANAN DAN STATUS SUMBERDAYA IKAN TERUBUK (Tenualosa macrura, Bleeker 1852), DI PERAIRAN ESTUARIN BENGKALIS DAN SELAT PANJANG

2018 ◽  
Vol 23 (4) ◽  
pp. 261
Author(s):  
Suwarso Suwarso ◽  
Muhammad Taufik ◽  
Akhmad Zamroni
Keyword(s):  
Sex Ratio ◽  
Species Conservation ◽  
Fishing Effort ◽  
Conservation Area ◽  
Gill Net ◽  
Spawning Stock ◽  
The Status ◽  
Long Time ◽  
Protandrous Hermaphrodite ◽  
Average Size

Ikan terubuk (Tenualosa spp.) adalah ikan estuarin bersifat ‘protandrous hermaphrodite’ dan endemik di estuarin sekitar Bengkalis. Jenis Tenualosa macrura ditemukan di sekitar Bengkalis (Riau), jenis T. ilisha di sekitar Labuhan Batu dan Labuhan Bilik (Sumatra Utara), sedangkan T. toli ditemukan di perairan pantai barat Pemangkat (Kalbar). Sumber daya terubuk di sekitar Bengkalis saat ini sangat menurun akibat eksploitasi dan recruitment overfishing meskipun pembatasan penangkapan telah diterapkan. Tulisan ini membahas status sumber daya ikan terubuk di sekitar Bengkalis dan Selat Panjang berdasarkan data monitoring hasil tangkapan periode 2014-2016 dan observasi lapangan selama 2015-2016. Ikan terubuk merupakan ikan dominan dari enam jenis hasil tangkapan pada gill net, jumlahnya sekitar 15% dari total hasil tangkapan, upaya penangkapan tergolong intensif sehingga penurunan upaya yang dilakukan ternyata kurang signifikan, bahkan pada saat close season dan close area (September sampai November) upaya penangkapan cenderung tinggi. Kondisi ini tentu tidak sesuai dengan tujuan perlindungan terbatas dan konservasi jenis yang diterapkan. Penurunan populasi terubuk tampak nyata dalam bentuk hasil tangkapan (CPUE), sex ratio maupun produksi pendaratan. Ikan kategori “Pias” (ikan jantan) tetap dominan dan semakin banyak, sebaliknya kategori “Terubuk” (ikan betina matang gonad) semakin sedikit, artinya ukuran rata-rata ikan juga semakin kecil. Keberadaan populasi ikan terubuk di sekitar P. Tiga (Kab. Kepulauan Meranti) dengan kondisi matang gonad dan secara genetik memiliki pola DNA yang sama dengan yang berada di Bengkalis. Perluasan daerah konservasi dan perlindungan terbatas terhadap stok-stok tersebut disarankan.The terubuk (Tenualosa spp) or shads, is a estuarine and endemic ‘protandrous hermaphrodite’ fish species. Species Tenualosa macrura is found in estuarine waters around Bengkalis (Riau Province), T. ilisha around Labuhan Batu and Labuhan Bilik (North Sumatera Province) while T. toli in west coast of Pemangkat (West Kalimantan Province). The terubuk reosurce in Bengkalis water is heavily degraded due to high exploitation and recruitment overfishing eventhough fishing limitation is applied. This paper is discussing the status of terubuk/longtail shad (Tenualosa macrura) resources in Bengkalis estuarine and Selat Panjang waters (Kabupaten Kepulauan Meranti) base on data of 2014-2016 catch monitoring data and field observation during 2015-2016. Terubuk is one of 6 dominant catches from gillnet, contributing about 15% of all catch. The fishing effort was so intensive even though management measure is applied to reduce its exploitation. During the close season when fishing on terubuk is banned (in September to November) as well as the ban in close area , the fishing effort has been still high. This condition is not in line with the objective of protecting the terubuk resources. Therefore, this condition must be changed and returned to objective of “limited protection” and “species conservation” by adopting a more strict rule on limiting fishing effort on terubuk through an evaluation. The decreasing of terubuk population can be seen from CPUE, sex ratio and also in landing, short time (2012 – 2016) and long time (18 years). In overall, the “Pias” (adult male) individuals remainned dominant and wereeven getting more in number, while the “Terubuk” (adult female) on the contrary, which means that the average size of actual fish cought was getting smaller. The existence of terubuk population around Pulau Tiga (Kabupaten Kepulauan Meranti) with mature gonad would share the same genetic pattern with population from Bengkalis. This explaines the connectivity between two stocks, at least there might be another spawning stock other than Bengkalis’s. The expand of the conservation area and limited protection on those stocks is highly recommended.

scholarly journals Sustainable exploitation of temperate fish stocks

2009 ◽  
Vol 6 (1) ◽  
pp. 124-127 ◽  
Author(s):  
Henrik Sparholt ◽  
Robin M. Cook
Keyword(s):  
Species Interactions ◽  
Fishery Management ◽  
Regional Scale ◽  
Single Species ◽  
Fishing Effort ◽  
Theoretical Concept ◽  
Maximum Sustainable Yield ◽  
Production Model ◽  
The Status ◽  
Long Time

The theory of maximum sustainable yield (MSY) underpins many fishery management regimes and is applied principally as a single species concept. Using a simple dynamic biomass production model we show that MSY can be identified from a long time series of multi-stock data at a regional scale in the presence of species interactions and environmental change. It suggests that MSY is robust and calculable in a multispecies environment, offering a realistic reference point for fishery management. Furthermore, the demonstration of the existence of MSY shows that it is more than a purely theoretical concept. There has been an improvement in the status of stocks in the Northeast Atlantic, but our analysis suggests further reductions in fishing effort would improve long-term yields.

Different but not opposed: perceptions between fishing sectors on the status and management of a crab fishery

2019 ◽  
Vol 77 (6) ◽  
pp. 2354-2368 ◽  
Author(s):  
Clara Obregón ◽  
James R Tweedley ◽  
Neil R Loneragan ◽  
Michael Hughes
Keyword(s):  
Fishing Effort ◽  
Environmental Pressures ◽  
Face To Face ◽  
The Social ◽  
The Status ◽  
Management Approaches ◽  
Sustainable Fishery ◽  
Average Size ◽  
Source Of Information ◽  
Western Australian

Abstract Fisher perceptions are a useful source of information that allows changes in stocks to be detected quickly and indicate the social acceptability of different management regulations. Yet traditionally, such information is rarely employed when developing management approaches. Face-to-face interviews were used to elicit recreational and commercial fishers’ perceptions of a crab (Portunus armatus) fishery in three south-western Australian estuaries. Differences in the perceived changes in the average size of crabs and fishing effort, reported concerns and supported solutions were detected among the recreational fishers utilizing the three estuaries and between recreational and commercial fishers in the Peel-Harvey Estuary. However, some common views were expressed by recreational and commercial fishers, with both sectors stating concerns over recreational fisher compliance and increased fishing and environmental pressures. While both sectors believed that reducing fishing and increasing compliance would benefit crab stocks, the mechanisms for achieving this differed. Recreational fishers favoured increasing the length of the seasonal closure, while commercial fishers favoured the introduction of a recreational shore-based fishing licence. These findings suggest that sector- and estuary-specific management rules may better facilitate the amelioration of pressures affecting individual estuaries and could contribute towards a more socially and biologically sustainable fishery.

Assessing abundance and catch selectivity of Octopus cyanea by the artisanal fishery in Lakshadweep islands, India

2018 ◽  
Vol 31 ◽  
pp. 10 ◽  
Author(s):  
Aditi Nair ◽  
Sutirtha Dutta ◽  
Deepak Apte ◽  
Balasaheb Kulkarni
Keyword(s):  
Sex Ratio ◽  
Stock Assessment ◽  
Fishing Effort ◽  
Local Economy ◽  
Fishing Activity ◽  
Island States ◽  
Juvenile Abundance ◽  
Long Time ◽  
Female Bias ◽  
Lakshadweep Islands

Subsistence fishery for cephalopods contributes significantly to the local economy of several Asian, African and island states. In addition to being unregulated and undocumented, recent studies indicate that low-scale fisheries can have detrimental effects on marine ecosystems. In the Lakshadweep islands, men, women and children have been involved in spear fishing for octopus for a long time, but there is a paucity of information on the biology and fishery of the octopus species in Indian waters. In this study, we estimated the population abundance, morphometry and sex ratio of Octopus cyanea. Moreover, we examined whether the current octopus spear fishing activity displayed size or sex selectivity, given that larger individuals are easier to spot and brooding females spend more time in crevices. O. cyanea surveys were conducted by snorkeling in the lagoons of Kavaratti and Agatti islands between November 2008 and April 2012. The estimated mean density of O. cyanea was 3 and 2.5 individuals per hectare in Agatti and Kavaratti, respectively. Individual mean weight was 923.36 g and 846.26 g in Agatti and Kavaratti and the male:female sex ratio 1.35:1 and 3.8:1, respectively. Comparison between visual counts and fisheries landings indicated that fishing effort was concentrated in areas of high juvenile abundance but without female-bias. Constructing a long-term database of fishery catches will help with stock assessment and understanding the factors that influence octopus populations. Implementation of a lower size limit of 500 g would act as a precautionary measure against catching very small octopuses.

scholarly journals Stock collapse or stock recovery? Contrasting perceptions of a depleted cod stock

2019 ◽  
Vol 76 (4) ◽  
pp. 787-793 ◽  
Author(s):  
R M Cook
Keyword(s):  
Mortality Rate ◽  
Gadus Morhua ◽  
Fishing Effort ◽  
Assessment Model ◽  
Fishing Mortality ◽  
Benchmark Assessments ◽  
Spawning Stock ◽  
The Status ◽  
Fishery Exploitation ◽  
Management Advice

Abstract ICES assessments of cod (Gadus morhua) in the west of Scotland (ICES Division 6a) suggest the biomass has collapsed and that fishing mortality rate (F) has remained high. In contrast, other stocks in the same fishery, and adjacent cod stocks all show marked declines in fishing mortality and some recovery of the biomass. The perception of the status of 6a cod appears to be dependent on the assumption that the fishery exploitation pattern is flat topped. An assessment that allows the exploitation to take a domed shape produces results that suggest a marked decline in fishing mortality rate and that the spawning stock biomass has recovered to the minimum biomass reference point, Blim. The reduction in F is consistent with substantial reductions in fishing effort and shows a similar pattern to stocks taken within the same fishery. The management implications arising from the two assessments differ substantially. The analysis indicates that benchmark assessments need to test assessment model conditioning assumptions more widely and that management advice needs to consider a more comprehensive range of information about the stock and fishery.

Fishery simulation model for sharks applied to the Gummy Shark, Mustelus antarcticus Gunther, from Southern Australian waters

1992 ◽  
Vol 43 (1) ◽  
pp. 195 ◽  
Author(s):  
TI Walker
Keyword(s):  
Sex Ratio ◽  
Simulation Model ◽  
Mesh Size ◽  
Fishing Effort ◽  
Probability Density Distribution ◽  
Natural Mortality ◽  
Sex Ratio At Birth ◽  
Gill Nets ◽  
Gill Net ◽  
Number Of Births

A dynamic pool simulation model is derived and applied to the gummy shark stock of the southern shark fishery. Inputs to the model are fishing effort reported by fishers for hooks and for gill-nets with mesh sizes of 6 inches (152 mm), 7 inches (178 mm) and 8 inches (203 mm) along with estimates for growth, natural mortality, catchability, hook and gill-net mesh selectivity, size at maturity and fecundity of females, sex ratio at birth, and length-weight relationships. Growth is described by the von Bertalanffy equation; hook selectivity is constant with length for sharks recruited to the fishery; gill-net selectivity is based on the probability density distribution of the gamma function where selectivity varies with the mesh size of the gill-nets and the length of the sharks; number of births is related to the proportion of females mature at each length, and the relationship between number of births and maternal weight is linear; parturition is annual and time is standardized so that parturition occurs at the beginning of each year; sex ratio at birth is based on observations of a 1: 1 sex ratio of embryos; and allometric weight-length is based on the power curve. Natural mortality of recruits, catchability, reproduction and growth parameters are held constant, but density-dependent natural mortality of prerecruits is varied in proportion to stock abundance. The model is used to simulate effects of historical longline fishing effort and gill-net fishing effort for each mesh size on stock biomass, numbers of sharks in the stock, and numbers of births. The performance of the model is evaluated by comparing simulated annual catches and the simulated mean weight of sharks captured with annual catches reported by the fishers and the mean weight of sharks sampled in commercial landings. Uncertainties surrounding estimates of some of the parameters are discussed. Notwithstanding its shortcomings, the model indicates that the stock of gummy shark has been severely reduced and is in danger of further depletion unless immediate action is taken to reduce the commercial catch.

Euratom and Brexit: Could the United Kingdom Maintain One Foot in the European Union? Current Scenarios and Future Prospects of British withdrawal from the EAEC

2018 ◽  
Vol 18 (2) ◽  
pp. 134-151
Author(s):  
Andrea Circolo ◽  
Ondrej Hamuľák
Keyword(s):  
European Union ◽  
United Kingdom ◽  
Independent Solution ◽  
Legal Regulation ◽  
The European Union ◽  
The United Kingdom ◽  
The Status ◽  
Long Time ◽  
Energy Community ◽  
The Impact

Abstract The paper focuses on the very topical issue of conclusion of the membership of the State, namely the United Kingdom, in European integration structures. The ques­tion of termination of membership in European Communities and European Union has not been tackled for a long time in the sources of European law. With the adop­tion of the Treaty of Lisbon (2009), the institute of 'unilateral' withdrawal was intro­duced. It´s worth to say that exit clause was intended as symbolic in its nature, in fact underlining the status of Member States as sovereign entities. That is why this institute is very general and the legal regulation of the exercise of withdrawal contains many gaps. One of them is a question of absolute or relative nature of exiting from integration structures. Today’s “exit clause” (Art. 50 of Treaty on European Union) regulates only the termination of membership in the European Union and is silent on the impact of such a step on membership in the European Atomic Energy Community. The presented paper offers an analysis of different variations of the interpretation and solution of the problem. It´s based on the independent solution thesis and therefore rejects an automa­tism approach. The paper and topic is important and original especially because in the multitude of scholarly writings devoted to Brexit questions, vast majority of them deals with institutional questions, the interpretation of Art. 50 of Treaty on European Union; the constitutional matters at national UK level; future relation between EU and UK and political bargaining behind such as all that. The question of impact on withdrawal on Euratom membership is somehow underrepresented. Present paper attempts to fill this gap and accelerate the scholarly debate on this matter globally, because all consequences of Brexit already have and will definitely give rise to more world-wide effects.

The Life-History of Badumna-Candida (Araneae, Amaurobioidea)

1993 ◽  
Vol 41 (5) ◽  
pp. 441 ◽  
Author(s):  
MF Downes
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Production Cycle ◽  
Social Spider ◽  
Social Spiders ◽  
Primary Sex Ratio ◽  
The Social ◽  
The Status ◽  
History Of ◽  
Changes Over Time

A two-year study of the social spider Badumna candida at Townsville, Queensland, provided information on colony size and changes over time, maturation synchrony, temperature effects on development, sex ratio, dispersal, colony foundation, fecundity and oviposition. Key findings were that B. candida outbred, had an iteroparous egg-production cycle between March and October, had an even primary sex ratio and achieved maturation synchrony by retarding the development of males, which matured faster than females at constant temperature. There was no overlap of generations, the cohort of young from a nest founded by a solitary female in summer dispersing the following summer as subadults (females) or subadults and adults (males). These findings confirm the status of B. candida as a periodic-social spider (an annual outbreeder), in contrast to the few known permanent-social spider species whose generations overlap. Cannibalism, normally rare in social spiders, rose to 48% when spiders were reared at a high temperature. This may be evidence that volatile recognition pheromones suppress predatory instincts in social spiders.

scholarly journals RELATIVE IMPACTS OF DIFFERENT DIETS ON THE QUALITIES OF ERI SILK COCOON AND ERI SILK YARN OF FOUR DIFFERENT MUTANTS STRAINS OF PHILOSAMIA RICINI Bsd.

2016 ◽  
Vol 4 (11) ◽  
pp. 77-81
Author(s):  
Akhilesh Kumar Gahlaut ◽  
Arjun
Keyword(s):  
Food Plants ◽  
Relative Impact ◽  
Shell Weight ◽  
Silk Cocoon ◽  
Average Production ◽  
The Status ◽  
Average Size ◽  
Eri Silk ◽  
Better Than ◽  
Silk Yarn

The relative impact of different food plants (diets) namely foliages of castor, kesseru , payam and Topioca plants on the four different mutant strain viz; yellow plain, yellow zebra ,G.B Plain ,G.B Zebra in respect of qualities of their eri cocoon and eri silk yarn have been evaluated under the reeling parameters.Result indicate that among the four different food plants like foliages of castor followed by kesseru have been found evidently better than the foliages of payam and Topiocal in respect of average cocoon weight (gm)4.10,3.55,3.98,3.10,Average shell weight (gm) 0.55,0.45,0.52,0.41,Average shell ratio 13.91,12.0,13.0,11.55,Average lengt- h of  silk yarn (mtrs) 2510,2350,2498,2285,Average size of erisilk(D)13D,11D,12D,19D,Average production of eri silk per hr(gm)13.70,12.50,13.10,11.95,Average tenacity of fibre (g/d) 14.0,11.0,12.0,10.0.As far as qualitative differences of all the four food plants in relation to qualities of eri cocoon and eri silk yarn are concerned the castor alongwith kesseru food plants have achieved the status of supremacy primary food plant and payam and tapioca the states of secondary food plants .These variation show that the qualities and production of eri silk cocoon and eri silk yarn depends on the different food plants.

scholarly journals The generality of post-antimicrobial treatment persistence of replicatively-attenuatedBorrelia burgdorferiin a mouse model

2019 ◽  
Author(s):  
Emir Hodzic ◽  
Denise M. Imai ◽  
Edlin Escobar
Keyword(s):  
Mouse Model ◽  
Antimicrobial Agents ◽  
Basic Feature ◽  
Antimicrobial Treatment ◽  
Therapy Failure ◽  
Treatment Persistence ◽  
Disease Resistant ◽  
C3h Mice ◽  
The Status ◽  
Long Time

ABSTRACTA basic feature of infection caused byBorrelia burgdorferi, the etiological agent of Lyme borreliosis, is that persistent infection is the rule, not the norm, in its many hosts. The ability to persist and evade host immune clearance poses a challenge to effective antimicrobial treatment. A link between therapy failure and the presence of persister cells has started to emerge. There is growing experimental evidence that viable, but non-cultivable spirochetes persist following treatment with several different antimicrobial agents, then resurge after 12 months. The current study utilized the mouse model to evaluate if persistence and resurgence occur following antimicrobial treatment in a disease-susceptible (C3H/HeN) and disease-resistant (C57BL/6) mouse strain infected withB. burgdorferistrains N40 and B31, to confirm the generality of these phenomena. The status of infection was evaluated at 12 and 18-months after treatment. The results demonstrated that persistent spirochetes remain viable for up to 18 months following treatment, but divide slowly, thereby being tolerant to the effects of antimicrobial agents, as well as being non-cultivable. The phenomenon of persistence and resurgence in disease-susceptible C3H mice is equally evident in disease-resistant B6 mice, and not unique to any particularB. burgdorferistrain. The results also demonstrate that following antimicrobial treatment, both strains ofB. burgdorferi, N40 and B31, lose one or more small plasmids, resulting in attenuation. The biological relevance of attenuatedB. burgdorferispirochetes is probably inconsequential. The study demonstrated that non-cultivable spirochetes can persist in a host following antimicrobial treatment for a long time but did not demonstrate their clinical relevance in a mouse model of chronic infection.

scholarly journals Micronuclei in blood lumphocytes of existing and former coal miners: evaluation of the effect of anthracosilicosis

2019 ◽  
Vol 17 (4) ◽  
pp. 57-64
Author(s):  
Vladimir G. Druzhinin ◽  
Svetlana V. Apalko ◽  
Elizaveta D. Baranova ◽  
Valentin P. Volobaev ◽  
Tatiana Yu. Drobchik ◽  
...  
Keyword(s):  
Coal Dust ◽  
Additional Contribution ◽  
Coal Miners ◽  
Genotoxic Effects ◽  
The Status ◽  
Long Time ◽  
Inflammatory Processes ◽  
Simultaneous Decrease ◽  
Genotoxic Risk ◽  
Cytogenetic Parameters

Background. The purpose of this study was to investigate the genotoxic risk in anthracosilicosis patients and in those with occupational exposure to coal dust. Materials and methods. We studied micronuclei (MN) and other cytogenetic lesions in blood lymphocytes in three groups of men comparable in age: 74 coal miners suffering from anthracosilicosis (AS), 41 healthy miners, and 70 control donors. Results. A significant increase in the frequency of MN was revealed with a simultaneous decrease in proliferative activity in samples of healthy and sick miners compared with the control. The level of MN in the lymphocytes of patients with AS significantly exceeded the corresponding indicator in the sample of healthy miners (1.22 0.05% versus 1.03 0.07%; p 0.01). The age of the subjects and the status of smoking did not have a significant effect on the frequency of cytogenetic parameters. Conclusion. AS in miners makes an additional contribution to the formation of DNA damage in lymphocytes. This contribution is probably due to oxidative stress accompanying inflammatory processes in pulmonary fibrosis. The results of the study also indicate the absence of differences in the frequency of MN when comparing subgroups of current and former miners. This means that the genotoxic effects in the lymphocytes of miners are able to persist for a long time after the termination of exposure by adverse factors in coal mining.

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