scholarly journals PERFORMANCE OF A FISHERY HARVESTING DIFFERENT MINIMUM SHRIMP SIZES IN THE ARAFURA SEA

2012 ◽  
Vol 18 (2) ◽  
pp. 79
Author(s):  
Purwanto Purwanto
Keyword(s):  
Fishery Management ◽  
Optimal Size ◽  
Natural Mortality ◽  
Economic Approach ◽  
Fishing Mortality ◽  
Arafura Sea ◽  
Total Profit ◽  
Bell Model ◽  
The Impact ◽  
Near Future

Avoiding overfishing and ensuring the sustainability of the shrimp stock in the Arafura Sea are of prime importance for fishery management. Exploited shrimp stock consists of several cohorts, and grows considerably with age. When the shrimps are caught before the cohort has had the opportunity to achieve its optimum biomass level, the fishery will lose much of the potential benefit that could be achieved by catching them in the near future. Therefore, a bio-economic approach was developed, on the basis of the length-based Thompson & Bell model, to evaluate the impact of harvesting different size of shrimps on fishery performance. The result of analysis shows that the fishery achieved the optimal total profit when the shrimp size at first-capture and fishing mortality were 29 mm CL and 0.50, respectively. The total profit to the fishery would be sub-optimal when the shrimp size at-first-capture was smaller or larger than the optimal size. Further, it was more economical to harvest shrimps at the larger size and higher fishing mortality, and resulting in higher total profit, when natural mortality decreased.

scholarly journals Minimizing the Impact of Yellowfin Tuna Thunnus albacares fishing in Banda Sea

2021 ◽  
Author(s):  
Haruna
Keyword(s):  
Fishery Management ◽  
Average Length ◽  
Yellowfin Tuna ◽  
Minimum Size ◽  
Thunnus Albacares ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Mortality Ratio ◽  
Tuna Fisheries ◽  
The Impact

The declining trend of Yellowfin Tuna Thunnus albacares production in Fishery Management Territory of Indonesia 714 nowadays will affect the demand for tuna products in Indonesia and global. Regarding the management purposes, the impact of fishing needs to be minimized. Therefore, the estimation of population structure based on the length and age is very important to be studied. The data were collected from November 2015 to October 2016 from longline and handline catching activities operated in the Banda Sea. The average length of yellowfin tuna caught with longline and handline was 98.5 cm and the first length maturity was Lm 103.6 cm. The result showed that the first yellowfin tuna caught was Lc_opt 125.2 cm, where fishing mortality ratio toward natural mortality was at the level that endangered the sustainability of yellowfin tuna fisheries in the Banda Sea. To minimize the impact, there needs to be a minimum size regulation of yellowfin tuna that should be landed

scholarly journals “The Elephant in the Room”: Exploring Natural Mortality Uncertainty in Statistical Catch at Age Models

2020 ◽  
Vol 7 ◽  
Author(s):  
Alessandro Mannini ◽  
Cecilia Pinto ◽  
Christoph Konrad ◽  
Paraskevas Vasilakopoulos ◽  
Henning Winker
Keyword(s):  
Stock Assessment ◽  
Assessment Process ◽  
Sensitivity Analyses ◽  
Fish Stock ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Food And Agriculture ◽  
Stock Assessments ◽  
The Mediterranean ◽  
The Impact

The natural mortality rate (M) of a fish stock is typically highly influential on the outcome of age-structured stock assessment models, but at the same time extremely difficult to estimate. In data-limited stock assessments, M usually relies on a range of empirically or theoretically derived M estimates, which can vary vastly. This article aims at evaluating the impact of this variability in M using seven Mediterranean stocks as case studies of statistical catch-at-age assessments for information-limited fisheries. The two main bodies carrying out stock assessments in the Mediterranean and Black Seas are European Union’s Scientific Technical Economic Committee for Fisheries (STECF) and Food and Agriculture Organization’s General Fisheries Commission for the Mediterranean (GFCM). Current advice in terms of fishing mortality levels is based on a single “best” M assumption which is agreed by stock assessment expert working groups, but uncertainty about M is not taken into consideration. Our results demonstrate that not accounting for the uncertainty surrounding M during the assessment process can lead to strong underestimation or overestimation of fishing mortality, potentially biasing the management process. We recommend carrying out relevant sensitivity analyses to improve stock assessment and fisheries management in data-limited areas such as the Mediterranean basin.

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
Chesapeake Bay ◽  
Total Mortality ◽  
Management Policy ◽  
Commercial Fishing ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Habitat Productivity ◽  
One Year ◽  
American Eels ◽  
The Impact

<em>Abstract.—</em>We examined the demography of American eels <em>Anguilla rostrata </em>at seven Maryland sites, including six Chesapeake Bay estuaries and one bay adjacent to the Atlantic Ocean. Eels caught by baited pots in estuaries tended to be young and small with rapid growth rates. Large eels were a higher proportion of catch in the Atlantic bay, where exploitation started only recently, than in heavily fished Chesapeake estuaries. Histological examinations indicated that all eels longer than 40 cm were female, but smaller eels were female, male, or undifferentiated in roughly equal proportions. Some eels were captured in commercial fishing gear after only one year in continental waters. Total mortality (<EM>Z</EM>), including postspawning mortality of emigrants, was estimated from catch curve analysis, giving a range of 0.62 to 1.44. Instantaneous natural mortality (<EM>M</EM>) was calculated as 0.25, from 3/maximum age (12). Instantaneous fishing mortality, <EM>Z</EM>–<EM>M</EM>, ranged from 0.37 to 1.19 and, in one case, only five age classes were observed. We considered the impact of latitude, habitat productivity, density, sex ratio, and fishing on eel populations. We postulate that heavy fishing pressure reduced the density and modal size of eels in surveyed estuaries. Changes in management policy to reduce fishing mortality and increase spawning emigration are recommended.

scholarly journals Effects of spatial heterogeneity in growth and fishing effort on yield-per-recruit models: an application to the US Atlantic sea scallop fishery

2015 ◽  
Vol 73 (4) ◽  
pp. 1062-1073 ◽  
Author(s):  
Samuel B. Truesdell ◽  
Deborah R. Hart ◽  
Yong Chen
Keyword(s):  
Spatial Heterogeneity ◽  
Spatial Data ◽  
Egg Production ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Sea Scallop ◽  
The Us ◽  
The Impact ◽  
Yield Per Recruit

Abstract Conventional yield-per-recruit (Y/R) and spawning-stock biomass-per-recruit (SSB/R) models make no allowance for spatial heterogeneity in fishing mortality, natural mortality, or growth across the stock area, although variability in these processes can affect model results. For example, areas with higher growth and/or lower natural mortality rates should be fished at a lower rate to maximize Y/R; however, these areas may be especially attractive to fishers and are often fished harder. Here, Y/R and SSB/R models are developed that simultaneously account for spatial heterogeneity in growth and fishing effort. These models are applied to the US Atlantic sea scallop (Placopecten magellanicus) fishery. The spatial variability in growth uses depth-integrated models from the literature and variability in effort is based on, alternatively, uniform, observed, and relative-optimal spatial harvesting distributions. The observed effort patterns are derived from vessel monitoring system positions, and illustrate one application for these widely collected but underutilized spatial data. In this example, the distribution of observed fishing effort reduces Y/R compared with the relative-optimal, or the uniform effort distribution implicitly assumed by conventional Y/R analysis. SSB/R was in some cases considerably higher under the relative-optimal distribution of effort than when calculated using observed or uniform effort patterns. Such more realistic spatially integrated Y/R and SSB/R models can help to evaluate the impact of effort patterns on fishery yield and stock egg production. These models demonstrate that the spatial distribution of effort can be as important as the overall average fishing mortality when managing fisheries to optimize Y/R, SSB/R, and yield.

scholarly journals Age, growth, mortality, and exploitation rate of blueline snapper, Lutjanus coeruleolineatus (Actinopterygii: Perciformes: Lutjanidae), from Dhofar Governorate, Sultanate of Oman

2021 ◽  
Vol 51 (2) ◽  
pp. 159-166
Author(s):  
Dawood Almamari ◽  
Said Rabia ◽  
Joo Myun Park ◽  
Laith A. Jawad
Keyword(s):  
Fishery Management ◽  
Growth Parameters ◽  
Total Mortality ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Fishing Mortality ◽  
Sultanate Of Oman ◽  
Commercial Fish ◽  
Exploitation Rate ◽  
Reported Study

The blueline snapper, Lutjanus coeruleolineatus (Rüppell, 1838), is a significant commercial fish species harvested from the traditional fishery in the Sultanate of Oman. Deficient data on this species, however, make the management strategies challenging, especially in fisheries ecology. A total of 978 specimens were obtained from Dhofar Governorate off the coast of the Arabian Sea during the period between February 2015 and March 2016. In total, 296 sectioned otoliths were analyzed and growth was estimated from non-seasonal growth by using von Bertalanffy method. The parameters of von Bertalanffy growth function, total mortality (Z), natural mortality (M), fishing mortality (F), and exploitation rate (E) were determined and compared with those for Lutjanidae fishes elsewhere. The age structure of male fishes was between 1 and 14 years for males while the age of females ranged from 1 to 18 years. Growth rate (K) was 0.21 y–1 and 0.16 y–1 for males and females, respectively. The hypothetical length of female (L∞ = 46 cm) was relatively higher than that of male (L∞ = 42 cm). The natural mortality (M) was 0.296, total mortality (Z) was 0.372, fishing mortality was 0.076, and exploitation rate (E) was estimated as 0.2. The presently reported study is conducted to examine this fish in relation to growth parameters by analyzing otolith structure. The results of the presently reported study will contribute towards planning the regional fishery management policies in Oman.

scholarly journals PARAMETER POPULASI UDANG DOGOL (Metapenaeus ensis) DAN UDANG WINDU (Penaeus monodon) DI LAUT ARAFURA

2017 ◽  
Vol 9 (1) ◽  
pp. 57
Author(s):  
Ali Suman ◽  
Budi Iskandar Prisantoso ◽  
Duranta D. Kembaren
Keyword(s):  
Population Dynamic ◽  
Carapace Length ◽  
Total Mortality ◽  
Growth Parameter ◽  
Assessment Tools ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Exploitation Rate ◽  
Tiger Prawn ◽  
Arafura Sea

Sumber daya udang di perairan Arafura merupakan salah satu modal menuju kemakmuran bagi bangsa, apabila dikelola secara berkelanjutan. Kajian dinamika populasi udang, merupakan salah satu dasar utama dalam merumuskan pengelolaan tersebut menuju pemanfaatan sumber daya yang lestari. Tujuan penelitian ini adalah untuk mengetahui dinamika populasi udang dogol dan udang windu di perairan Arafura dan sekitarnya. Penelitian dilakukan dari bulan Januari 2013 sampai dengan Nopember 2013 dan analisis dilakukan dengan menggunakan FAO-ICLARM Fisheris Stok Assessment Tools (FISAT). Hasil penelitian menunjukkan bahwa laju pertumbuhan (K) udang dogol sebagai 1,33 per tahun dan panjang karapas maksimum (L) sebagai 52,0 mm. Untuk udang windu didapatkan nilai K sebagai 1,45 per tahun dan nilai L sebagai 62,5 mm. Laju kematian total (Z) udang dogol sebagai 4,79 per tahun, laju kematian karena penangkapan (F) dan laju kematian alami (M) masing-masing 2,91 per tahun dan 1,88 per tahun. Untuk udang windu didapatkan nilai Z sebagai 6,13 per tahun, nilai F dan nilai M masing-masing 4,24 dan 1,89 per tahun. Laju pengusahaan (E) udang dogol 0,61 per tahun dan nilai E udang windu sebagai 0,69 per tahun. Tingkat pemanfaatan sudah berada dalam tahapan overfishing dan perlu dilakukan pengurangan jumlah upaya 22% untuk udang dogol dan 38% untuk udang windu.Shrimp resources within Arafura Sea if under sustainably management it would contribute a significant role as a source of nation welfare. Scientific advice on population dynamic are required as an input to support an apropriate fisheries management. The purpose of the study was to identify population parameters of the endeavour shrimp and tiger shrimp in Arafura Sea. Study on the population dynamic of endeavour shrimp and king tiger prawn were conducted in Arafura Sea based on data collected during period of survey, January 2013 to November 2013. The analysis is using the FAO-ICLAM Fisheries Stock Assessment Tools (FiSAT). Result showed that the growth parameter of endeavour shrimp was 1.33/year with maximum carapace length (L) of 52.0 mm. Instantenous total mortality (Z) and natural mortality (M) were 4.79/year and 1.88/year, respectively. While fishing mortality (F) and exploitation rate (E) of endeavour shrimp respectively were 2.91/year and 0.61/year. The growth parameter of king tiger prawn was 1.45/year with maximum carapace length (L) of 62.5 mm. Instantenous total mortality (Z) and natural mortality (M) were 6.13/year and 1.89/year, respectively. While fishing mortality (F) and exploitation rate (E) of king tiger prawn respectively were 4.24/year and 0.69/year. The exploitation rate of endeavour shrimp and king tiger prawn in Arafura Sea was overfishing. It was, therefore, recommended that fishing effort of 22% the endeavour shrimp and 38% king tiger prawn in that waters should be reduced in the next year.

scholarly journals Viewpoint: the interface between scientific advice and fisheries managementa

2007 ◽  
Vol 64 (4) ◽  
pp. 846-850 ◽  
Author(s):  
Kjartan Hoydal
Keyword(s):  
Fisheries Management ◽  
Fishery Management ◽  
Objective Assessment ◽  
Social Constraints ◽  
Scientific Advice ◽  
Fishing Mortality ◽  
Management Framework ◽  
The North ◽  
Sustainable Fishery ◽  
The Impact

Abstract Hoydal, K. 2007. Viewpoint: the interface between scientific advice and fisheries management. – ICES Journal of Marine Science, 64: 846–850. Basic elements in responsible, robust, and sustainable fishery management frameworks are well understood and easily listed. Common sense and international law underline the prominent role of science in management. Most managers request peer-reviewed advice based on an objective assessment of the impact of fisheries on marine ecosystems, to create a basis for sustainable and profitable fisheries. Management systems in the North Atlantic rely extensively on advice on total allowable catches (TACs) to control fishing mortality in stocks under regulation. This leads to an unhelpful focus on inherently uncertain catch forecasts. With the wisdom of hindsight, TACs have rarely led to the predicted reduction in fishing mortality. And because of the focus on TACs, other elements in the management framework, notably overcapacity and other economic and social constraints, do not receive the necessary attention. A comparison of the way fishing advice is acquired with the same process in the hydrocarbon extraction industry draws attention to the multi-user problem in marine fisheries management.

Syrian Crisis and Migration

2015 ◽  
Vol 12 (3) ◽  
pp. 181-192 ◽  
Author(s):  
Pinar Yazgan ◽  
Deniz Eroglu Utku ◽  
Ibrahim Sirkeci
Keyword(s):  
Human Mobility ◽  
Special Issue ◽  
Host Countries ◽  
Syrian Crisis ◽  
Mass Migration ◽  
Large Numbers ◽  
And Migration ◽  
Europe Today ◽  
The Impact ◽  
Near Future

With the growing insurrections in Syria in 2011, an exodus in large numbers have emerged. The turmoil and violence have caused mass migration to destinations both within the region and beyond. The current "refugee crisis" has escalated sharply and its impact is widening from neighbouring countries toward Europe. Today, the Syrian crisis is the major cause for an increase in displacement and the resultant dire humanitarian situation in the region. Since the conflict shows no signs of abating in the near future, there is a constant increase in the number of Syrians fleeing their homes. However, questions on the future impact of the Syrian crisis on the scope and scale of this human mobility are still to be answered. As the impact of the Syrian crisis on host countries increases, so does the demand for the analyses of the needs for development and protection in these countries. In this special issue, we aim to bring together a number of studies examining and discussing human mobility in relation to the Syrian crisis.

The Supply-Demand Research of Cultural and Tourism Industries Policies in China with the Impact of COVID-19

2020 ◽  
Vol 11 (1) ◽  
pp. 24-24
Author(s):  
Dr. Jianfei Yang
Keyword(s):  
Tourism Industry ◽  
Chinese Government ◽  
Cultural Industries ◽  
Real Situation ◽  
The Real ◽  
The World ◽  
The Impact ◽  
Near Future ◽  
Post Period

COVID-19 has made a bad influence on economic and society including cultural and tourism industry in China，2020.The industry has received a huge loss in the first quarter of the year and the situation is getting worse in the near future. It is believed that there will be a long impact for the country even the world. In order to recover the industry, Chinese government has published series of policies to support the enterprises and clusters to reduce the bad influence of COVID-19. This paper mainly uses filed survey and documentary research to map the real situation of the industry. It tries to find the policy demand of the industries and then analyze the policies published by government to conquer COVID-19. Meanwhile it will focus on whether the supply meet the demand and give suggestions on how to promote the policy efficiency in the post period of COVID-19 in China. Keywords: Evaluation; Cultural Industries; Policy; Park; Pandemic

scholarly journals Using Satellite Data for CBRN (Chemical, Biological, Radiological, and Nuclear) Threat Detection, Monitoring, and Modelling

2021 ◽  
Author(s):  
Gary Sutlieff ◽  
Lucy Berthoud ◽  
Mark Stinchcombe
Keyword(s):  
Satellite Data ◽  
Meteorological Data ◽  
Atmospheric Composition ◽  
Chemical Detection ◽  
List Type ◽  
Data Types ◽  
Wide Range ◽  
Future Technologies ◽  
The Impact ◽  
Near Future

Abstract CBRN (Chemical, Biological, Radiological, and Nuclear) threats are becoming more prevalent, as more entities gain access to modern weapons and industrial technologies and chemicals. This has produced a need for improvements to modelling, detection, and monitoring of these events. While there are currently no dedicated satellites for CBRN purposes, there are a wide range of possibilities for satellite data to contribute to this field, from atmospheric composition and chemical detection to cloud cover, land mapping, and surface property measurements. This study looks at currently available satellite data, including meteorological data such as wind and cloud profiles, surface properties like temperature and humidity, chemical detection, and sounding. Results of this survey revealed several gaps in the available data, particularly concerning biological and radiological detection. The results also suggest that publicly available satellite data largely does not meet the requirements of spatial resolution, coverage, and latency that CBRN detection requires, outside of providing terrain use and building height data for constructing models. Lastly, the study evaluates upcoming instruments, platforms, and satellite technologies to gauge the impact these developments will have in the near future. Improvements in spatial and temporal resolution as well as latency are already becoming possible, and new instruments will fill in the gaps in detection by imaging a wider range of chemicals and other agents and by collecting new data types. This study shows that with developments coming within the next decade, satellites should begin to provide valuable augmentations to CBRN event detection and monitoring. Article Highlights There is a wide range of existing satellite data in fields that are of interest to CBRN detection and monitoring. The data is mostly of insufficient quality (resolution or latency) for the demanding requirements of CBRN modelling for incident control. Future technologies and platforms will improve resolution and latency, making satellite data more viable in the CBRN management field

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