Stock Size Research Articles

Optimization of a Marine Fish Release Strategy: A Case Study of Black Sea Bream Acanthopagrus schlegelii in the Zhanjiang Estuary, Northern South China Sea

The release strategy (choice of the species and locations stocked, releasing mode, and stocking size and times) is an important part of quantitative evaluations of marine fish stock enhancement, while optimization of the release strategy can contribute to assess the stocking success intended to alleviate declining fishery resources and to increase the income of fishers. In this study, a typical fish species released in the northern South China Sea, black sea bream Acanthopagrus schlegelii, was taken as the research object. The biological characteristics of this sparid were determined from samples collected from waters in the Zhanjiang estuary during June, July, and September 2020 to April 2021, and the data were applied to estimate its length frequency and its growth parameters using the ELEFAN I run in FiSAT II. We then simulated and evaluated the stocking effects of five scenarios under different release strategies, while assuming a fixed total quantity of released fish and a constant of mortality rate at different life stages. The results showed that (1) the breeding season of black sea bream in this region is mainly from December to March of the next year, which is also the period when most significant sexual reversal in this species occurs, and (2) the relationship between standard length and weight in black sea bream is W = 5.092 × 10–5L2.906, L∞ = 54.39 cm, K = 0.15, and t0 = −0.967. (3) The recommended period to release black sea bream in Zhanjiang waters is from June to October. It appears more productive if the total quantity of fish released can be divided into two batches. The growth potential of released juvenile fish in this study was evaluated based on a density-dependent theory, and the stocking effect of released stocks was simulated with the consideration for biological parameters and field sampling technique. This study provides a reference for the optimization of fish release strategies in coastal waters.

Treatment with Oral Appliances in Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a disorder caused by a number of factors like an obstruction of the upper airway during sleep because of insufficient motor tone of the tongue and/or airway dilator muscles or inadequate growth of the maxillary jaw bone etc. Oral appliances (OAs) are commonly used as a non-invasive treatment for obstructive sleep apnea syndrome. The primary oral appliance (OA) used in obstructive sleep apnea (OSA) treatment is the mandibular advancement device (MAD). Tongue-retaining devices or tongue-stabilizing devices (TSDs) are a second type of OA, which displace the tongue anteriorly and may be customized or come in different stock sizes. This review article aims to examine the best in class on this particular subject of treatment of OSA with oral appliances, explaining acceptability of an appliance in patients on the basis of its construction and results, while providing enough cognizance regarding the diagnosis, management and causes of discontinuation.

Carbon stocks differ among land-uses in agroforestry systems in western Canada

Agroforestry systems (AFS) are increasingly being recognized as sustainable land-use systems that can increase carbon (C) sequestration and improve food security. However, the relative contributions of various C pools to the overall C stock of AFS and their dependence on factors such as tree age, species diversity and density is still unclear in many regions. Using an equivalent soil mass approach, we investigated the effect of three different AFS (hedgerow, shelterbelt, and silvopasture) and their component land-use types (treed areas and adjacent cropland/grassland) on various C pools across 36 sites in central Alberta, Canada. On average, the treed area within AFS stored 178.5 t ha−1 more C relative to adjacent cropland or grassland, although the total C stock did not differ among the three AFS types. Most of the C in the treed area of AFS was stored in the mineral soil (61%), overstory trees (28%), and the LFH (litter, partially decomposed litter and humus, 10%) layer, while midstory trees, shrubs, and understory vegetation together accounted for the remaining 1% of the C storage. The C stock size in the treed area was closely associated with tree stand characteristics of the three AFS, with the C pool size in the LFH positively related to tree age. Our results highlight that the amount of C stored in the LFH layer is substantial and should be considered when assessing C storage within AFS and suggest that investing in AFS can be an effective strategy for meeting part of Canada's C reduction goals to mitigate climate change.

ANALYSIS OF THE VOLUME OF PASSENGERS AND CARGO IN RAIL AND ROAD TRANSPORT IN POLAND IN 2009-2019

Transport plays an important role in the economy of any country. Efficient and developed transport infrastructure of various modes of transport significantly affects the availability of transport services, and consequently, the well-being of citizens. This article presents an analysis of the volume of passengers and cargo transport using rail and road transport in Poland in 2009-2019. These analyses were carried out based on data obtained from the Central Statistical Office. All data concerns Polish entities that provide services in the field of passenger and freight transport in Poland and focuses on such information as the volume of passengers and cargo by individual means of transport, broken down into domestic and international transport. Further, the presented analyses concern the length of the available rail and road routes, tracks, the size of the rolling stock as well as the groups of transported loads.

РАЗВИТИЕ МЕТОДИЧЕСКОГО ИНСТРУМЕНТАРИЯ ВНУТРЕННЕГО КОНТРОЛЯ ДВИЖЕНИЯ ЗАПАСОВ

One of the factors for the effective development of enterprises is the rational management of stocks, the state of which affects its production and financial activities. For the rational management of stocks, their effective control should be organized, taking into account the specifics, scale and features of production technology. The purpose of the research is to improve the methodological support of internal control over the movement of stocks. In the course of the study, the main stages of internal control of the movement and the efficiency of using stocks, consisting in planning and carrying out control measures, were considered. In order to comply with the principles of rationality, priority and consistency in the conduct of internal control, it was proposed to use the working document “The program for internal control of the movement and efficiency of inventory use”. Checking the correctness of the estimate of stocks when they are received, procured, or purchased is possible using the internal control working document “Checking the correctness of stock estimates”. It makes it possible to identify errors in the assessment of stocks and the formation of their actual cost, which affects production costs and the final financial result. For the analysis of the movement of stocks, we can recommend the internal control working paper “Analysis of the movement of stocks”. It allows you to control the compliance of the actual size of stocks of the most important types of raw materials and materials with the normative ones. By comparing the incoming and outgoing stocks on the basis of this document, it is possible to identify excessive and unclaimed material resources in the production and financial activities of the enterprise, to establish stocks for which there is a shortage, to prevent a decrease in the quality of products, a decrease in production volumes, a decrease in profits

Analisis Kinerja Keuangan Dan Ukuran Perusahaan Terhadap Harga Saham Studi Empiris Pada Perusahaan Sektor Finansial Yang Terdaftar Di Bursa Efek Indonesia Periode 2017-2019

Stock prices show a reference for investors in making investment decisions, stock prices often change according to supply and demand teams. period 2017-2019. Sample selection was done by using purposive sampling technique. In this study, the sample used was the Financial Sector companies listed on the Indonesia Stock Exchange for the 2017-2019 period as many as 52 companies with the amount of data processed for 3 years, namely 156 companies. The type of data used is secondary data obtained from the Indonesia Stock Exchange website, namely www.co.id in the form of company financial statements. In this study using multiple analysis tools using the SPSS program with version 21.0. The regression equation of this study is Y = -1.523 + 0.863 X1 + 0.603 X2. The results of this study indicate that ROA has no effect on stock prices. while Roe has a positive and significant influence on stock prices. Meanwhile, Roi has no effect on stock prices and Size has no effect on stock prices.

Prospects for a saturation of humanity’s resource use? An analysis of material stocks and flows in nine world regions from 1900 to 2035

Material stocks in infrastructure, buildings and machinery shape current and future resource use and emissions. Analyses of specific countries and selected materials suggest that material stocks might saturate, which would be important for a more sustainable social metabolism. However, it is unclear to what extent the evidence holds for a wider range of stocks and flows, as well as for world regions or globally.We present an inflow-driven dynamic stock-flow model for 14 bulk materials, end-of-life outflows, recycling, and waste flows for nine world regions from 1900 to 2015, extended with trend scenarios until 2035. Material stocks are growing in all regions and show little signs of saturation yet. In 2015, China used half of global stock-building materials, overtook everyone in stock size around 2012 and grows its stock at ∼8%/year. The Industrialized regions, including the Former Soviet Union, are slowly expanding their high stock levels at ∼1%/year. Stocks in all other regions, inhabited by 60% of the world population, grow at ∼3–5%/year. Inequalities in per capita stocks between regions are large. Trend scenarios suggest potential absolute or per capita stock saturations in some of the industrialized regions, while all other regions are expected to continue high stock growth.Accumulated stocks drive future end-of-life materials and substantial maintenance and replacement requirements. Growing material stocks hamper a potential stabilization or reduction of resource use. Low stock levels in most world regions suggest a crucial window of opportunity for avoiding resource-intensive stock development. In the industrialized regions and especially China, stabilising and reducing resource use requires halting net stock expansion and transforming existing stocks. More materials- and energy-efficient and long-lived stocks which deliver high quality services, and improved reuse, repair and recycling of increasing end-of-life materials to close loops and actually replace virgin resources, are crucial for a more sustainable social metabolism.

The sociometabolic transition of a small Greek island: Assessing stock dynamics, resource flows, and material circularity from 1929 to 2019

Their geomorphological characteristics make island systems special focal points for sustainability challenges. The Circular Economy (CE) Action Plan of the European Union foresees tailored solution sets for Europe's outermost regions and islands to tackle region-specific sustainability challenges. We address the question of how islands can achieve more sustainable resource use by utilizing the socioeconomic metabolism (SEM) framework to assess and explore CE strategies for the Greek island of Samothraki. For this purpose, we apply material and energy flow analysis on a regional level and derive, as one of the first studies, a complete time series from 1929 to 2019 for socioeconomic biophysical stocks and flows according to mass-balance principles for an island economy. Results show that in the past 90 years Samothraki's material stocks grew fivefold, domestic material consumption threefold, and solid waste generation fivefold. Samothraki transitioned from an almost entirely circular biophysical economy toward one in which 40% of input materials and 30% of output materials are estimated as non-circular. This transition resulted in an accumulated solid waste stock on the island almost half the size of current material stocks in use. With this study we aim at providing ideas and opportunities for achieving more sustainable and circular material use on small islands. The published SEM database aims at supporting the public and the private sector and the island community at large with information key to establishing more sustainable material and energy use patterns on Samothraki. This article met the requirements for a Gold–Gold JIE data openness badge described at http://jie.click/badges.

Kinerja Produksi Ikan Lele (Clarias gariepinus sp) dengan Ukuran Tebar Berbeda Pada Sistem Akuaponik

Catfish (Clarias gariepinus Burchell, 1822) is a type of freshwater fish that is prospectively cultivated. This study aims to analyze the production performance and economic analysis of catfish on aquaponics technology with floating raft systems. This research was conducted descriptively with two treatments and four replications. The treatments included fish sizes, which were 6-9 cm (A) and 3-4 cm (B). The fish used were fish with an initial weight of 7.13±1.30 g and 4.11±0.43 g, the plant used was water spinach (Ipomoea reptans poir) with an initial height of 8-10 cm. The results showed that there was a trend of increasing fish weight during the study from 7.13±1.30 g and 4.11±0.43 g to 110.02±6.09 g and 86.44±5.00 g at the end of the study. . The survival rate value during the study was 100% for all treatments, the feed conversion value ranged from 1.48-1.59. The highest specific weight growth rate was 1.60%/day. Water spinach production during catfish rearing can be done for 3 harvests. The analysis of the aquaponics business of the floating raft system is very efficient and profitable. The value of R/C ratio > 1 in all treatments means that the cultivation business is said to be feasible. Payback period of 0.57 years (A) and 0.19 years (B), the fastest return on investment is in treatment B. Aquaponics floating raft system with catfish stocking size 3-4 cm for 60 days of maintenance period provides the best production performance with SR value was 60.78%, specific weight growth rate was 0.051%/day, feed conversion was 1.18 and the best kale production was 75 kg. Economically, this research is feasible to do.

Boosting the Equity Momentum Factor in Credit

Machine learning techniques have gained popularity in recent years but only to a limited extent in fixed-income research. This article shows some new work in the application of “boosted regression trees” for the equity momentum factor in the corporate bond market. We report significant performance gains to investors from using machine learning–driven forecasts, roughly doubling the alpha and information ratio of better known equity momentum strategies. In addition to past equity returns, we include size and liquidity of stocks and bonds in our model framework.

Linking soil organic carbon stock to microbial stoichiometry, carbon sequestration and microenvironment under long-term forest conversion

Forest conversion can drastically impact carbon (C) and nutrient processes and microbial stoichiometry, which will modify soil organic C (SOC) stock. However, SOC stock dynamics and its underlying mechanisms induced by long-term forest conversion remain unclear. Three well-protected plantations converted from natural forests for 36 years were compared, i.e., Cryptomeria fortunei (CF), Metasequoia glyptostroboides (MG) and Cunninghamia lanceolata (CL), with a natural forest (NF) as a control. SOC stock size and stability across three soil depths (0–10, 10–30 and 30–60 cm) were examined with aggregate-based method. Forest floors and fine roots were treated as C and nutrient inputs while soil respiration (Rs) was treated as C output. Soil microbial biomass C, nitrogen and phosphorus were measured to calculate microbial stoichiometry, as well as microenvironment and soil physicochemical properties. The relationships between SOC stock (size and stability) and these factors were explored using structural equation model. The results showed that microbial stoichiometry had strong or strict homeostasis at each soil depth. At 0–10 cm soil deep, SOC stock size varied with tree species (following the rank of CL > NF ≈ CF > MG) but its stability increased in all forest conversion types, regulated by forest floor quantity and quality associated with Rs; at 10–30 cm soil deep, the SOC stock sizes decreased in CF and MG, but SOC stock stability increased in MG, jointly driven by fine root quality and microenvironment; at 30–60 cm soil deep, SOC stock size decreased but its stability increased in MG, whereas both its size and stability had few changes in CF or CL, modified by soil physicochemical property associated with microbial stoichiometry and Rs. Overall, the effects of microbial stoichiometry and microenvironment on SOC stock were not pronounced. Thus, SOC stock size changed with soil depth and tree species but its stability tended to be steady at all depths varying with tree species. These results suggest that SOC stock size and stability are mainly determined by self-regulation process of forest ecosystems over more than three-decade after forest conversion, which will help us more accurately assess C sequestration strategies regarding long-term forest conversion.

Absolute Abundance Estimates for Red Snapper, Greater Amberjack, and Other Federally Managed Fish on Offshore Petroleum Platforms in the Gulf of Mexico

AbstractOffshore petroleum platforms provide habitat utilized by an array of reef fish that are valuable to both commercial and recreational fishers. However, thousands of offshore platforms have been decommissioned in the Gulf of Mexico over the past decade, with many of the removals being accomplished using explosive severance methods. Here, we estimate the impact of platform removal in the Gulf of Mexico on five stocks of federally managed reef fish based on the percentage of each stock that is resident on platforms. We conclude that the gulfwide impact of removal will be relatively minor (1% to 8% of the estimated stock abundance) for four species, Red Snapper Lutjanus campechanus, Gray Triggerfish Balistes capriscus, Vermilion Snapper Rhomboplites aurorubens, and Cobia Rachycentron canadum. In contrast, losses for the Greater Amberjack Seriola dumerili stock would potentially represent 45% of the known stock. An alternative explanation is that the actual abundance of Greater Amberjack is much larger than the most recent stock size estimate; in either case, we suggest this issue needs further examination. Removal impacts could also be significant for reef‐fish fisheries (especially the Red Snapper fishery) in areas where platforms are presently abundant but other high‐relief natural or artificial reefs are not present. Removal of the platforms from these areas will greatly impact the local fisheries.

Genetic parameters and genotype by environment interaction for production traits and organ weights of gilthead seabream (Sparus aurata) reared in sea cages

Gilthead seabream is a key fish species for farming in the Mediterranean region and is farmed in a large geographical area under various production circumstances. However, more than 80% of the genetically improved fingerlings originate from a single country, Greece, which poses a potential risk for genotype by environment interaction (GxE). Therefore, the objective of this study was to quantify GxE for several traits of gilthead seabream in two distinct commercial production sites, one in south of Greece (Galaxidi Marine Farm) and another in southeast of Spain (Cudomar). For this GxE experiment, a population of juveniles was produced by mass spawning of 33 males and 20 females on a single day. These juveniles were stocked in sea cages in both locations when they reached stocking size (~3 g) and grown under commercial conditions. Management conditions during the grow-out period were kept the same between the production sites, while the fish were subject to naturally occurring differences such as water temperature, dissolved oxygen, and salinity. Phenotypes were recorded when the fish reached commercial harvest size (~400 g). Genetic parameters were estimated by using a genomic relationship matrix that was built by using ~30 k SNP. All traits studied had higher genetic variation and heritabilities in Cudomar. For instance, the heritability of harvest weight was 0.37 ± 0.05 in Galaxidi and 0.55 ± 0.05 in Cudomar. GxE was estimated as genetic correlations between the same trait measured on different fish in the two environments. Moderate GxE was found for harvest weight (0.45 ± 0.11), growth (0.43 ± 0.11), fillet weight (0.49 ± 0.12), liver weight (0.61 ± 0.11), and viscera weight (0.62 ± 0.10). Weak GxE was found for fillet fat (0.87 ± 0.06), heart weight (0.76 ± 0.11), cardiosomatic index (0.93 ± 0.14), viscerosomatic index (0.90 ± 0.05), and hepatosomatic index (0.79 ± 0.09). In conclusion, moderate GxE estimates for growth traits indicate that with a single breeding program, performance data from both environments should be included, or that two separate breeding programs may be needed for the two environments. The higher genetic variances observed in Cudomar suggest that this environment is a more suitable test environment for selective breeding.

РЫБОХОЗЯЙСТВЕННАЯ ХАРАКТЕРИСТИКА ЩУКИ ESOX LUCIUS (L.) ТОПО-ПЯОЗЕРСКОГО ВОДОХРАНИЛИЩА (ВОДОСБОР БЕЛОГО МОРЯ)

The article presents the results of the work carried out within the framework of forecast topics and economic contractual topics aimed to assess the stock and production of pike in the Topo-Pyaozero (Kumskoe) Reservoir. There have been studied its main biological and structural-population indicators. Calculations of indicators of pike’s abundance and biomass at the present stage, necessary for the rational regulation of the fishery have been carried out. It was found that the fishing possibilities of the presented pike populations correspond to the production possibilities of its sexually mature part and the value obtained as a result of the biomass increase. Pike should be taken into the commercial operation from the age of 4+ years and older. The performed calculations of the stock size based on the materials of 2009–2020 recommend the volume of the pike total allowable catch at the present stage not less than 36 tons, or 21% of the value of the commercial stock (at the maximum rate of 23.4%). From the results of observations it follows that the abundance and stocks of pike in the Topo-Pyaozero Reservoir make it possible to provide large volumes of catch at the present time, and the total catch can be increased to the calculated values the volume of the allowable catch, provided that a rational fishery is maintained in water bodies. The intensity of fishing and an increase in pike catches in the reservoir should be considered as mandatory measures in terms of biological reclamation in reservoirs

The stock market as a casino: Associations between stock market trading frequency and problem gambling.

Background and aimsPersonal investors decrease their stock market investment returns by trading frequently, which the behavioral finance literature has primarily explained via investors' overconfidence and low levels of financial literacy. This study investigates whether problem gambling can help account for frequent trading in a sample of active gambler/investors, as suggestive of frequent trading being in part driven by a behavioral addiction to gambling-like activities.MethodsA retrospective cross-sectional study of 795 US-based participants, who reported both being active gamblers and holding stock market investments. Recollected stock trading activity (typical portfolio size, purchases and sales of stocks) was compared with scores on the Problem Gambling Severity Index, a financial literacy scale, and a measure of overconfidence.ResultsSelf-reported relative stock portfolio turnover was positively associated with problem gambling scores. This association was robust to controls for financial literacy, overconfidence, and demographics, and occurred equally among investors of all self-reported portfolio sizes.Discussion and conclusionsThis study provides support for the hypothesis that behavioral addiction to gambling-like activities is associated with frequent stock market trading. New investment products that increase the ease of trading may therefore be detrimental to some investors.

Validating a biophysical dispersal model with the early life-history traits of common sole (Solea solea L.).

Larval dispersal and juvenile survival are crucial in determining variation in recruitment, stock size and adult distribution of commercially important fish. This study investigates the dispersal of early-life stages of common sole (Solea solea L.) in the southern North Sea, both empirically and through modeling. Age at different life-history events of juvenile flatfish sampled along the coasts of Belgium, the Netherlands and the United Kingdom in 2013, 2014 and 2016, was determined through the counting of daily growth rings in the otoliths. Juveniles captured between August and October were estimated to be on average 140 days old with an average pelagic larval duration of 34 days. The hatching period was estimated between early April and mid-May followed by arrival and settlement in the nurseries between May and mid-June. Growth rates were higher off the Belgian coast than in the other nursery areas, especially in 2013, possibly due to a post-settlement differentiation. Empirical pelagic larval duration and settlement distributions were compared with the Larvae&Co larval dispersal model, which combines local hydrodynamics in the North Sea with sole larval behavior. Yearly predicted and observed settlement matched partially, but the model estimated a longer pelagic phase. The observations fitted even better with the modelled average (1995–2015) distribution curves. Aberrant results for the small juvenile sole sampled along the UK coast in March 2016, led to the hypothesis of a winter disruption in the deposition of daily growth rings, potentially related to starvation and lower food availability. The similarities between measured and modelled distribution curves cross-validated both types of estimations and accredited daily ageing of juveniles as a useful method to calibrate biophysical models and to understand early-life history of fish, both important tools in support of efficient fisheries management strategies.

An Acoustic Study on the Overwintering Black Sea Anchovy in 2020

The Black Sea anchovy (Engraulis encrasicolus ponticus) is not only the top commercial species with around 250 thousand tonnes of annual catch but a key species of the Black Sea ecosystem facilitating the flow of energy within the food chain. The General Fisheries Commission for the Mediterranean has assessed the status of its stock for the Mediterranean since 2013. Underlining the shortcomings in the assessments, the commission has recommended diversifying and strengthening the data used and promote methods that provide biomass and abundance indices, such as hydroacoustics. This study aims to help fulfill the underlined deficiency by pursuing the implementation of the hydro-acoustic research surveys in the Turkish Black Sea EEZ. The survey was carried in November/December 2020, when the anchovies were accumulated within the Turkish EEZ, and cruise tracks were designed to cover the distribution areas of juvenile (0-year-old) and adult (Age 1 and over) anchovies displaying different distribution patterns within the Turkish EEZ in winter. The results show that the stock size is noticeably smaller than in previous years. Pelagic trawl sampling conducted alongside the acoustic data collection to estimate the size composition of anchovies indicated that the juvenile fish constitute an alarmingly large part of the overwintering stock.

Influence of Steelhead Trout Stocking Size and Location on Emigration and Adult Returns

AbstractEffective stocking programs are an essential part of maintaining most high‐quality tributary steelhead Oncorhynchus mykiss fisheries in the Great Lakes, requiring sufficient numbers of stocked fish to survive, imprint, and return as adults. New York’s Lake Erie tributaries have long supported popular and economically important recreational steelhead fisheries, attracting anglers from across the country. Recent research has illustrated New York’s dependence on “stray” steelhead from other jurisdictions, making New York fisheries vulnerable to other agencies’ management decisions. We hypothesized that the limited contribution by New York‐stocked steelhead was attributable to poor poststocking survival and imprinting due to the smaller stocking size relative to other Lake Erie jurisdictions. We took an experimental approach to describe how the combination of stocking size and within‐stream stocking location interact to influence emigration and adult returns and identify mechanisms that may be driving these relationships, with the goal of identifying stocking strategies that improve adult returns. Stocked steelhead >150 mm total length emigrated from the stream by the end of May; small‐size steelhead tended to remain in the stream and exhibited upstream migration. The residual population of steelhead lost body condition and likely experienced high mortality. Adult returns from large‐size fish that were stocked 6.4 km upstream were 4.1 times greater than small‐size fish stocked upstream and six times greater than fish stocked near the lake confluence (0.8 km upstream). We conclude that many of the steelhead stocked by New York are too small to imprint and emigrate, instead remaining as stream residents that experience poor survival and ultimately make minimal contributions to the adult fishery. Increases in the stocking size of New York steelhead coupled with stocking well upstream of the lake confluence would result in increased adult returns of New York‐stocked fish to their streams of origin and improved fishery performance and resiliency.

Spatio-temporal interactions between Northeast Atlantic Mackerel and its fishery - Simulating different futures

The mackerel (Scomber scombrus) stock is one of the commercially most important pelagic species in the Northeast Atlantic, being targeted by various nations. Environmental and stock size changes caused a stock expansion after 2007, initiating a yet unresolved dispute between the European Union, United Kingdom, Iceland, Greenland and the Faroe Islands. We analyze the impacts of different Total Allowable Catches (TACs) on the mackerel stock and possible adaptations in simulated fleet behavior by applying an age-structured bio-economic optimization and simulation model, FishRent. We implement dynamic seasonal migration patterns, which alter the spatial extension of mackerel depending on biomass levels, assuming density dependent mechanisms. If true, this is an important consideration because it may provide the possibility for major fishing parties (the European Union, Norway and the UK) to exclude minor parties (Iceland) from fishing mackerel by selecting a high enough fishing pressure and therefore keeping the stock from migrating further north. This can, for instance, be achieved by setting a corresponding TAC. When applying a TAC under a business-as-usual scenario or higher, the stock biomass decreased close to BMSY on the long-term. In this case, the Danish fleets would benefit, increasing their profit up to 80%. All other fleets were negatively affected with a profit decreasing between 50% and 100% depending on the scenario. When applying a TAC according to the stock advice, the stock biomass was estimated to increase on the long-term. This benefitted the Irish and British fleets, but effects on the Icelandic fleet were neutral.

Stock Size Assessment, Distribution and Biology of the Surf Clam Mactra stultorum (Mollusca: Bivalvia) Along the Sfax Coasts (Tunisia, Mediterranean Sea)

Stock Size Assessment, Distribution and Biology of the Surf Clam Mactra stultorum (Mollusca: Bivalvia) Along the Sfax Coasts (Tunisia, Mediterranean Sea)