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Inland rift valley lake systems have been sustaining humanity for a long time. Only recently have commercial fisheries entered these systems and for Lake Malawi, this occurred in the mid-1970s upon successful experimental trawl fishing. Lake Malawi with the highest diversity of freshwater fishes in the world has had fisheries for centuries. Previous assessment of the impact of commercial trawl fisheries revealed significant changes in stock composition and overall biomass. The study evaluates the state of fisheries resources using novel techniques developed using integrated assessment methods amenable to data poor fisheries. Data from biomass assessment surveys and landed catch from 2016 to 2019 were examined to determine the status of selected fish stocks over time. Stock Synthesis for Data Limited tools in R environment were used to run the models. The Surplus Production Models and Statistical catch-at-age models that were used to examine alternative hypotheses on life history parameters on the key stocks exploited primarily by the commercial trawl fishery and evaluate long-term trends on these populations. The study results revealed that Mcheni (Rhamphochromis spp.), Ndunduma (Diplotaxodon limnothrissa) and Utaka (Copadichromis virginalis) stocks are within the sustainable limits, while Chambo (Oreochromis karongae), Chisawasawa (Lethrinops gossei), Mlamba (Bathyclarias nyasensis) and Kampango (Bagrus meridionalis) appear to be overfished in recent years, though Kampango may have recovered recently. Given, the large uncertainties with productivity of most tropical fishes with climate change, as well as large uncertainties due to inaccurate and untimely data submissions, it is recommended that a systematic monitoring and evaluation program, like the one being conducted in Lake Malawi should be developed for other inland lake systems. If stocks are facing overfishing by both the small-scale and commercial trawl fisheries, limits to overall catch and size should be implemented possibly through output controls such that the fisheries remain sustainable for the long term. [ABSTRACT FROM AUTHOR]

Elasmobranchs are declining worldwide due to overfishing. In developing countries and island states in tropical regions, small-scale and recreational fisheries can significantly impact the dynamics of neritic species. We investigated elasmobranch diversity at Reunion Island, a marine biodiversity hotspot in the Western Indian Ocean. Combining information from the literature, catches from the local shark control program, results from a survey of local recreational fishing, and through barcoding of some specimens, we updated the list of elasmobranchs to 65 species. However, uncertainties remain about the actual presence of some species, such as the three sawfish species. Results highlight the disappearance of most coral reef-associated species, as already suspected. Results also suggest that local populations of scalloped hammerhead shark (Sphyrna lewini) and bottlenose wedgefish (Rhynchobatus australiae) seem healthy, in contrast with their decline in the region. For some species, such as bull sharks (Carcharhinus leucas) and scalloped hammerhead sharks, Reunion Island is a site of reproduction, and as such, the species are exploited at both juvenile and adult stages, which likely increases their vulnerability. In the context of global elasmobranch decline, it is urgent to clarify the conservation status and evaluate the degree of isolation of local populations to identify research and conservation priorities. [ABSTRACT FROM AUTHOR]

Abstract. The Fez-Meknes basin consists geomorphologically of the Meknes plateau to the west and the saïss plain to the east, separated by the Ain Taoujtat flexure. It is characterized by a semi-arid climate. Hydrogeologically, the basin contains two important aquifer reservoirs, a free and a captive water table. The first one circulates in the Plio-Villafranchian formations, while the second one is deep in the dolomitic limestone of the Lias. These two aquifers communicate with each other in some places, either directly through flexures and faults or indirectly through upward drainage. They are the main sources of drinking water and irrigation. These two aquifers have been overexploited due to successive years of drought and agricultural use. Thus, this work aims to monitor the piezometric level of the free water table through several field trips, technical data sheets of the drillings, geological and topographical maps. The analysis of rainfall data in the stations located around the piezometers in the study area allowed to distinguish a low water period (June, July, August and September) and a high-water period (March, April and May). The piezometric maps were made on the basis of the comparison between kriging and TIN during the low and high-water period. The TIN method has been recommended as the most reliable one.

Aim Location Methods Results Main Conclusions Land‐use change and overexploitation are major threats to biodiversity, and climate change will exert additional pressure in the 21st century. Although there are strong interactions between these threats, our understanding of the synergistic and compensatory effects on threatened species' range geography remains limited. Our aim was to disentangle the impact of habitat loss, hunting and climate change on species, using the example of the endangered Chacoan peccary (Catagonus wagneri).Gran Chaco ecoregion in South America.Using a large occurrence database, we integrated a time‐calibrated species distribution model with a hunting pressure model to reconstruct changes in the distribution of suitable peccary habitat between 1985 and 2015. We then used partitioning analysis to attribute the relative contribution of habitat change to land‐use conversion, climate change and varying hunting pressure.Our results reveal widespread habitat deterioration, with only 11% of the habitat found in 2015 considered suitable and safe. Hunting pressure was the strongest single threat, yet most habitat deterioration (58%) was due to the combined, rather than individual, effects of the three drivers we assessed. Climate change would have led to a compensatory effect, increasing suitable habitat area, yet this effect was negated by the strongly negative and interacting threats of land‐use change and hunting.Our study reveals the central role of overexploitation, which is often neglected in biogeographic assessments, and suggests that addressing overexploitation has huge potential for increasing species' adaptive capacity in the face of climate and land‐use change. More generally, we highlight the importance of jointly assessing extinction drivers to understand how species might fare in the 21st century. Here, we provide a simple and transferable framework to determine the separate and joint effects of three main drivers of biodiversity loss. [ABSTRACT FROM AUTHOR]

The unsustainable harvest of species for the global wildlife trade is a major cause of vertebrate extinction. Through the anthropogenic Allee effect (AAE), overexploitation to extinction can occur when a species' rarity drives up its market price, enabling profitable harvest of all remaining individuals. Even in the absence of rarity value, however, the harvest of other species can subsidize the overexploitation of a rare species to the point of extinction, a phenomenon termed opportunistic exploitation. These two pathways to extinction have been considered independently, but many traded species experience them simultaneously.In this study, we develop a simple model that incorporates these mechanisms simultaneously and demonstrate that including multiple harvest strategies with market‐based feedbacks fundamentally alters rare species extinction risk and the rate at which overexploitation occurs. As a pertinent case study, we consider the harvest of ground pangolins Smutsia temminckii.Our results show that pangolin extinction was generally associated with high rarity value, the use of multiple harvest strategies and the simultaneous harvest of a common species that has a fast life history. Pangolin population depletion and short‐term extinction risk were greatest when harvesters used a combination of pursuit and opportunistic (i.e. multi‐species) harvest strategies.Policy implications. Our results suggest that feedbacks between multiple financial incentives to overharvest can exacerbate the risk of extinction of rare species. As a result, continuing to address AAE and opportunistic exploitation as separate extinction pathways may insufficiently capture extinction risk for many exploited species. Criteria for assessing extinction risk or harvest sustainability of exploited species should incorporate multiple drivers of harvest pressure, with an expanded focus on including species with high rarity value that are exploited in multi‐species harvest regimes. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigated Reeves' turtle (Mauremys reevesii) using radiotelemetry to determine its habitat selection and home range in Qichun County, Hubei Province, China. The results show that this is a semi-aquatic species and not purely aquatic, as previously categorized. When active in terrestrial habitats, these turtles prefer low-canopy cover habitats near the edges of fields with abundant shelter. They also prefer areas with many shelter opportunities in aquatic habitats, particularly shallow habitats near the water's edge. Our study's average home range area was larger than those noted in previous studies. Furthermore, many human activities occurred within their active area, threatening the Reeves' turtle population. Protecting the habitat of Reeves' turtles is crucial for their survival, and efforts should be made to preserve some of their original habitat from exploitation. Our results fill a gap in knowledge of the natural history of this endangered species. Habitat selection and range are crucial factors in understanding the life history of species. We tracked 23 adult wild Reeves' turtles (Mauremys reevesii) from August 2021 to August 2022 in Qichun County, Hubei Province, China, to study their habitat selection, home range, and the characteristics of chosen habitats. Significant differences were observed in aquatic habitats, regarding shelter cover (Z = −6.032, p < 0.001), shelter height (Z = −6.783, p < 0.001), depth of water (Z = −2.009, p = 0.045), and distance from the edge (Z = −4.288, p < 0.001), between selected and random habitats. In terrestrial habitats, significant differences were observed in canopy cover (Z = −2.100, p = 0.036), herbage cover (Z = −2.347, p = 0.019), distance from the field edge (Z = −2.724, p = 0.006), dead grass cover (Z = −2.921, p = 0.003), and dead grass thickness (t = 3.735, df = 17, p = 0.002) between the selected and random habitats. The mean home range area observed for this turtle population was 14.34 ± 4.29 ha, the mean core home range was 2.91 ± 2.28 ha, and the mean line home range was 670.23 ± 119.62 m. This study provides valuable information on this endangered species, providing a foundation for the development of conservation plans. [ABSTRACT FROM AUTHOR]

The Upper Victoria Nile (UVN) flows from Lake Victoria into Lake Kyoga, spanning 117 km and supports a diverse aquatic fauna that sustains livelihoods of riverside communities. The UVN is habitat to critically endangered (Labeo victorianus), near threatened (Oreochromis variabilis and Oreochromis esculentus), and rare species (Neochromis simotes). Four hydropower dams were built on the UVN to provide energy for industrial and socioeconomic development, notwithstanding consequential environmental and socioeconomic impacts. The impacts of Bujagali hydropower (BHP) dam on fisheries and livelihoods were assessed biannually (April and September) from 2006 to 2019, using fishing effort, species abundance, catch composition, and economic beach revenue at upstream, mid‐reservoir, and downstream transects. The fishing boats increased from 31 in 2009 to 293 in 2019 and fishers from 83 to 500 over the monitoring period. Maximum annual catch of 461.4 t was recorded in 2014 and lowest of 54.2 t in 2009. In all transects, Protopterus aethiopicus and Labeo victorianus were least in the commercial catches and the use of Mormyrus kannume juveniles as bait for Nile perch fishery corresponded with increased catches from 3.3 t in 2009 to 148.2 t in 2019. Women were mostly engaged in post‐harvest activities such as fish drying, smoking, and food vending. These observations suggest coupling effects of the hydropower dam and ineffective fisheries management. The harvest of M. kannume wild stocks for bait should be banned and research in possible domestication of the species undertaken. There is a need to strengthen fisheries enforcement to curb illegal effort and overexploitation and to implement conservation actions to mitigate potential biodiversity impacts from the hydropower dam operations. [ABSTRACT FROM AUTHOR]

Lake sturgeon (Acipenser fulvescens) was historically abundant in Lake of the Woods, Canada/USA, and was the first species to be commercially harvested from that waterbody commencing in 1888. The number of pound nets used annually was documented from 1888 to 1910 and used as a surrogate for effort in a surplus-production model using a Bayesian approach. Mean dressed weight was 11.35 kg; therefore, the total biomass and approximate number of sturgeon harvested could be estimated. Over the 23-year period, 5348 tonnes were harvested peaking at 813.3 tonnes in 1893. Effort peaked in 1896 whereas catch-per-unit-effort peaked in 1891 at 11.4 tonnes per pound net year. The estimated historical initial biomass (B0) was 4493 tonnes (2059–9689; 95% CIs) and population was 395,859 sturgeons (181,409–853,656). Carrying capacity was estimated at 10,825 tonnes (2676–40,697; 95% CIs) and the intrinsic growth rate (r) was estimated to be 0.092 (0.009–0.272; 95% CIs). Maximum sustainable yield was 235 tonnes (14–1012; 95% CIs) which was exceeded 3.5 times by the third year (1891) of commercial harvest and extended seven more years until the population declined. The mean rate of exploitation was 13.2% over the 23-year period, peaked at 36.5% in 1896 and declined to approximately 10% after the 1900s. The population in Lake of the Woods in 1910 was estimated to be 34,397 (13,814–80,966; 95% CIs) representing a decline of 91.1% from the beginning of the commercial harvest in 1888. [ABSTRACT FROM AUTHOR]

The article presents the discussion on sustainable use of wild species benefitting biodiversity and human well-being in South Africa. Topics include South Africa's National Development Plan 2030 reducing poverty and inequality supporting more inclusive rural and urban economies; and enabling South African perspectives informing the global assessment and policy recommendations.

Seawater intrusion represents a high risk for the water supply, the agriculture and industry activities in the lower Seybouse region of North-Eastern Algeria. In order to analyze this risk, a three-dimensional model was developed using the MODFLOW and MT3DMS codes to predict seawater intrusion in the coastal aquifer. The application of this model indicates that the groundwater withdrawals result in a continuous decrease of the water level and in an increase of chloride concentration. Moreover, the salt front could progress by 300 to 2500 m in the land. These results show the necessity of adequate measures for the protection of the aquifer. Numerical predictions for 2045, considering an increase of groundwater withdrawals by 20%, show a fairly significant decrease in water levels, up to -6 m with respect to the mean sea level, and an increase of Cl- concentrations up to about 10 km inland.

The Socotra Archipelago (Yemen), a group of four islands off the north-eastern tip of Africa in the western Indian Ocean, has a population that relies heavily on small-scale fishing for livelihoods and food security. However, the reporting of fisheries catches by Yemen has consistently been incomplete, with artisanal (small-scale, commercial) catches underreported and small-scale non-commercial subsistence and recreational catches not reported at all. Here, we reconstruct the total small-scale catches and fishing effort from the waters of the Socotra Archipelago for 1950 to 2019, and derive catch-per-unit-effort (CPUE) estimates for these fisheries. The catch officially reported by the Food and Agriculture Organization on behalf of Yemen that was assumed taken from the archipelago is thought to be around 20% of the total reconstructed catch for the archipelago. The reconstructed small-scale catch increased from ~1,500 t in 1950 to an all-time peak of 12,000 t in 2000 before declining to 3,300 t by 2014. Thereafter, catches increased again slightly to just over 3,700 t·year-1 by 2019. Artisanal catches accounted for around 70% of total small-scale catches prior to 2010, but made up only around 46% by 2019. Conversely, subsistence catches increased from ~1,000 t in 2010 to ~2,000 t in 2019, and accounted for 54% of total catches by 2019. Small-scale fishing effort increased by over 1000% since 1950 and reached over 11 million kWdays by 2019. The CPUE derived for small-scale fisheries declined by 78% since 1950, from 1.4 kg·kWday-1 to 0.3 kg·kWday-1 in 2019, with most of the decline occurring after 2000. Our findings suggest resource overexploitation, and may assist efforts to more sustainably manage the Socotra Archipelago’s fish stocks. Small-scale fisheries support food and nutrient security of the local population, not least during political and humanitarian crises such as in Yemen.

The sustainable exploitation of natural resources constitutes a real-world problem of interest for many fields. In this work, we study those situations in which the exploiting agents have information about the state of the resource and their own benefits and costs but not about the behavior or performance of the rest of the agents. Cognitive Hierarchy Theory provides a framework for those low-information scenarios by focusing on the assumptions that agents make about other individuals’ behavior. Motivated by this theory, we introduce a theoretical agent-based model in which agents exhibit varying degrees of rationalization when exploiting the resource, and this resource’s evolution is driven by a differential equation that mirrors the dynamics of real-world resource growth. Our results show that, although most regimes imply depletion, higher benefits and sustainability are obtained when agents assume overexploitation by the rest and try to compensate for it. Furthermore, many exploiting agents and a long-term perspective also involve a better resource state, reaching the optimal exploitation level when all these factors come together.

Muraenesox bagio (black eel) and Congresox talabonoides (brown eel) are two major eels (Muraenesocidae) species which are commercially significant in the marine catch of Bangladesh, but population dynamics and stock assessment of marine eel fishery in Bangladesh are yet to be studied. This study is the first endeavour to analyze the population dynamics and stock assessment of this marine eels collected from July 2021 to May 2022 using three length-based methods namely TropFishR, the Length Based-Spawning Potential Ratio (LB-SPR) & the length-Based Indicators (LBI) and two catch-based methods including Depletion-Based Stock Reduction Analysis (DB-SRA) and the Catch-Maximum Sustainable Yield (CMSY). A slightly positive allometric growth pattern (b=3.10) for the black eel and a negative allometric growth pattern (b=2.33) for the brown eel were observed in the length-weight relationship. The parameters of von Bertalanffy Growth Function (VBGF) and the linearized length-converted catch curve (LCCC) analysis for black eel and brown eel were L∞=190.67cm and 166.63cm, k=0.18 year-1 and 0.16 year-1, and the total mortality, Z=0.70 year-1 and 0.45 year-1. The eel fishery is calculated to be overfished due to overexploitation and the stock’s spawning biomass (SPR=19% for black eel and 21% for brown eel) is close to the limit reference point but well outside the targeted range because the majority of the catches were found to have below-maturity levels. This study advised an optimum length limit to catch from 93 to 114 cm for black eel and 83 to 101 cm for brown eel. Though the estimated reference points of the CMSY were more optimistic than those from the DB-SRA, the tendency of the status of eel stock has been displayed moving towards overexploitation from a safe stock scenario. This study, therefore, recommended an annual landing limit of 250 mt as OFL (Over fishing limit) for the next ten years in association with existing management measures to maintain the present stock biomass of eel fishery over the BMSY level.

The aim of this study is to assess the main climatic characteristics and their impact on the hydrological regime at the watershed and the hydrodynamic functioning of the aquifer in the Eastern Mitidja plain (Algeria, 2,382 millions km2). In detail, specific objectives are to determine the recharge mode of the aquifer, to propose solutions for the groundwater overexploitation and to remedy the seawater problem in its northeastern part. The application of three statistical methods (Pettitt’s, Buishand’s U statistic and, Lee and Heghinian’s tests) and two drought indices (SPI and Ipmc) allowed identifying the wet and dry periods for the time interval 1906-2018. In addition, the piezometric maps analysis for the years 1973, 1981, 2015 and 2020 was carried out to investigate the hydrodynamic behavior of the study area and to determine the effect of the hydrological regime on the hydrogeological functioning of the aquifer. Results obtained by the application of the three statistical methods and two drought indices indicate two distinct periods. The first period is wet and it extends from 1906 to 1973, while the second period is dry and it goes from 1974 to 2018. It is characterised by a rainfall deficit between 15% and 19% compared to the previous period (1906-1973). Furthermore, a significant drawdown in the piezometric levels is observed from 1973 to 2020, varying between 10 and 80 m, that indicates a negative trend of piezometric levels. This drawdown coincides with the rainfall deficit noticed during the period 1973-2018. Also, seawater intrusion was observed in the northeastern part of the plain. To enhance groundwater management, an effective remediation strategy is to use an artificial recharge technique from the existing wastewater treatment plants in the region, complemented by stopping the pumping of wells in coastal zones that are affected by seawater intrusion supplemented by a hydro-chemical monitoring of the groundwater.

The world's biodiversity is in peril. The major threats to biodiversity globally are habitat change, overexploitation, climate change, invasive species and pollution. Not only do these stressors impact free-living organisms, but they affect parasitic ones as well. Herein, this perspective examines the potential consequences of these anthropogenic perturbations on helminth populations and communities, with emphasis on significant developments over the past decade. Furthermore, several case studies are examined in more detail for each of these threats to biodiversity. While effects are widespread and diverse, for the most part all these environmental stressors have negative effects on parasite populations and communities. Those parasites with complex life cycles that are trophically transmitted are often more at risk, although larval parasites with a wide host spectrum, and directly transmitted ectoparasites, appear less threatened and may even benefit. However, differential effects on hosts and parasites, on parasite life cycle stages and on host–parasite interactions made specific predictions difficult and context-dependent. Experimental laboratory and mesocosm studies on specific parasites that test effects on the different life cycle stages, hosts and host–parasite interactions, permitting the determination of net effects of an environmental stressor, yield insightful and sometimes counterintuitive results, although they remain a simplification of real-world complexity. Recent advances in the use of parasites as bioindicators of effects also are discussed. [ABSTRACT FROM AUTHOR]

The Fez-Meknes basin consists geomorphologically of the Meknes plateau to the west and the saïss plain to the east, separated by the Ain Taoujtat flexure. It is characterized by a semi-arid climate. Hydrogeologically, the basin contains two important aquifer reservoirs, a free and a captive water table. The first one circulates in the Plio-Villafranchian formations, while the second one is deep in the dolomitic limestone of the Lias. These two aquifers communicate with each other in some places, either directly through flexures and faults or indirectly through upward drainage. They are the main sources of drinking water and irrigation. These two aquifers have been overexploited due to successive years of drought and agricultural use. Thus, this work aims to monitor the piezometric level of the free water table through several field trips, technical data sheets of the drillings, geological and topographical maps. The analysis of rainfall data in the stations located around the piezometers in the study area allowed to distinguish a low water period (June, July, August and September) and a high-water period (March, April and May). The piezometric maps were made on the basis of the comparison between kriging and TIN during the low and high-water period. The TIN method has been recommended as the most reliable one. [ABSTRACT FROM AUTHOR]

In this paper, we propose a Rosenzweig--MacArthur predator-prey model with strong Allee effect and trigonometric functional response. The local and global stability of equilibria is studied, and the existence of bifurcation is determined in terms of the carrying capacity of the prey, the death rate of the predator and the Allee effect. An analytic expression is employed to determine the criticality and codimension of Hopf bifurcation. The existence of supercritical Hopf bifurcation and the non-existence of Bogdanov--Takens bifurcation at the positive equilibrium are proved. A point-to-point heteroclinic cycle is also found. Biologically speaking, such a heteroclinic cycle always indicates the collapse of the system after the invasion of the predator, i.e., overexploitation occurs. It is worth pointing out that heteroclinic relaxation cycles are driven by either the strong Allee effect or the high per capita death rate. In addition, numerical simulations are given to demonstrate the theoretical results. [ABSTRACT FROM AUTHOR]

The exploitation status of Tenualosa ilisha (hilsa) stocks from the riverine and marine region of West Bengal was compared in this study for the first time. The study showed that both the values of exponent and condition factor for hilsa reduced over time when compared with previous studies from the same region. Population dynamics study showed the exploitation rate (E) for the riverine hilsa stock were 0.74, 0.79, and 0.78 during pre-monsoon, monsoon, and post-monsoon, respectively, whereas in marine stock, the values were 0.59, 0.64, and 0.71 during pre-monsoon, monsoon, and post-monsoon indicating higher fishing pressure on the riverine hilsa stock. The riverine fishing mortality rate (F) (pre monsoon, 0.83 year−1; monsoon, 11.1 year−1; post-monsoon, 11.5 year−1) was higher than the marine sector (pre monsoon, 0.33 year−1; monsoon, 0.50 year−1; post-monsoon, 0.41 year−1). The fishery in both these sectors was capturing the first spawners of the hilsa population with a 75% probability. Thus, it was evident that the fishing practice in both the studied regions was unsustainable in nature and the exploitation of hilsa in the riverine part was more intense compared to the marine region. All these changes were causing altered population dynamics and fluctuation in the recruitment pattern of hilsa in West Bengal leading towards the dwindling of annual catch of this species. [ABSTRACT FROM AUTHOR]

The black pomfret (Parastromateus niger) is one of the high-income-generating carangid fish species and the only known member of its genus. This study aims to identify existing gaps in stock status and population demography of this species and provide viable management recommendations to enhance the sustainability of this fishery. Therefore, three methodological approaches have been used in this study; TropFishR to present the current exploitation status, the length-based spawning potential ratio (LB-SPR) to quantify stock spawning biomass, and Froese's sustainability indicators (LBI) to establish a basic standard for sustainable management of the fishery. In the length-weight relationship of black pomfret, an allometric growth pattern (b = 2.19) was found. The VBGF life history parameters for black pomfret were L∞ = 55.25 cm, K = 0.54 year−1, and based on LCCC analysis, the total mortality (Z = 1.61 year−1), natural mortality (M = 0.69 year−1) and fishing mortality (F = 0.91 year−1) are calculated. The result reveals that this fishery is currently suffering from overexploitation and the stock's spawning biomass (SPR = 13%) is below the limit reference point because most of the catch (82%) was found to be under the maturity level. Based on the results, this study recommended strictly maintaining the mesh size of the net to ensure not to catch immature fish with a length smaller than 30.63 cm, recommended the length to catch be between 29 and 35 cm, and reducing fishing pressure by one-third to ensure the sustainability of the black pomfret fishery. [ABSTRACT FROM AUTHOR]

Reeves' turtle (Mauremys reevesii) originated in China and was once one of the most widely distributed and abundant hard-shelled turtles in China; however, overharvesting has led to a sharp decline in its wild populations. A survey of Reeves' turtle was conducted from July 2021 to March 2022 in Qichun County, Hubei Province, China. A total of 74 individuals were caught in 26 ponds (1078 trap-days), indicating a catch effort population density of 0.07 individuals/trap-day. The 840 similar ponds in the field-surveyed towns indicate a population number of 2391 individuals and density of 4 individuals/km2. Our preliminary results suggest that Reeves' turtle populations face serious threats from human hunting activities, habitat destruction, and artificial release and urgently require an aggressive conservation program to ensure their survival. [ABSTRACT FROM AUTHOR]

One‐third of the world's trees are at risk of extinction, with large, old, long‐lived trees among the most vulnerable. Long‐lived trees in arid and semi‐arid biomes are particularly at risk, including Australian sandalwood (Santalum spicatum, Santalaceae), which is experiencing substantial population decline due to a suite of natural and anthropogenic drivers, with no appreciable recruitment estimated for more than 80 years. To contextualize this range‐wide collapse and quantify regional variation in population dynamics across Australia's western rangelands, we investigated the size‐class profiles of 12 sandalwood populations in a 1,500‐kilometre arc between Shark Bay and the Gibson Desert in central Western Australia including Indigenous Protected Areas, pastoral leases and public and private conservation parks and reserves. Stem diameters, indicative of age using known growth rates, were recorded for 1,355 sandalwood plants, along with a set of another plant structural and ecological parameters. Using size‐class profiles and associated demographic data, we estimated the population age structure and trajectory to determine whether each population was increasing, stable or declining. Our surveys revealed sandalwood populations are declining and are composed almost entirely of very old trees in advanced states of senescence. Of 1,355 plants sampled, 1,198 (88.4%) individuals were large (old) trees. A total of 23 seedlings and 21 saplings were recorded across all sites, almost all of which (22 and 19, respectively) were in one population, and located under the canopies of parent trees where they would not be expected to survive to maturity. Our findings reinforce the urgent need to list Santalum spicatum as a threatened species in Western Australia (where wild plants are still being commercially harvested) and to initiate effective conservation actions to secure the species' continued existence across its natural range. [ABSTRACT FROM AUTHOR]

As the country with the world's largest fishing capacity, China suffers from the depletion of living marine resources, mainly caused by overexploitation, the effects of which also distinctly influence global sustainable utilization of marine resources and maritime order. The country has implemented a series of measures to control its national fishing capacity, notably since the late 1980s, and strongly expressed its responsibility and commitment to sustainable resource utilization in the 13th Five-Year Plan (2016–2020). This study quantitatively assesses the effect of China's fishing capacity management efforts by examining changes in the fishing capacity of marine capture fisheries by region from 1979 to 2019 in Chinese waters, based on window data envelopment analysis (DEA), and further proposes directions for policy adjustment. The results suggest that China's coastal and offshore fisheries are still subject to overcapacity of approximately 20%, despite major corrective efforts invested in past decades. This implies that China needs to further improve its fishing capacity management and set clear objectives, as determined by the availability of resources and regional features. Global fisheries management's focus is shifting from input to output control, but overcapacity still threatens the sustainable use of fisheries resources in China and poses obstacles to other systems. [ABSTRACT FROM AUTHOR]

Groundwater depletion in the Urucuia Aquifer System (UAS) has concerned the Brazilian water agencies since it is the principal water source in the arid length of the São Francisco river. In contrast, the irrigation fields increasing and uncertainty regarding climate variability have impaired the management of this important hydrograph region of Brazil. Therefore, the proper management of the UAS relies on the correct definition of the factors that are impacting most of the ground and surface waters, i.e., whether they are from climate or anthropogenic activities. Relying on Artificial Intelligence (AI) modeling and hydrological signatures, this study proposed a methodology to disentangle the role of climatic variability and groundwater pumping on streamflow dynamics by rebuilding natural time series in four watersheds within the UAS's boundaries. By comparing the natural to the observed streamflow time series, the long-term 90th percentile (Q_90) discharge, from which 80% can be granted for multiple uses in the State of Bahia, decreased by up to 50% in the UAS. Yet, the watersheds' productivity, given by the 90% specific yield, ranged from −52.3% (3.8 L/s.km2 to 1.8 L/s.km2) to −74.0% (23.4 L/s.km2 to 6.1 L/s.km2). Low flow duration was ∼1650 days in natural conditions and increased to 10,354 days in the current land use and cover scenario. Changes in the maximum low flow duration length ranged from 191.7% to 1315.7%, and in the low flow, deficits were up to 7150%. These results highlight that groundwater pumping is the principal factor of the UAS's dryness since climate variability could not track streamflow decreases. However, climate variability is secondary because of the intensification of the atmosphere demand. Although it is a Brazilian application, the proposed methodology can be applied in other aquifer systems to guide decision-makers' management strategies worldwide. [Display omitted] • Groundwater overexploitation decreased the water availability in the UAS. • The proposed methodology is a tool to direct the management strategy. • Anthropogenic activities are the main cause of groundwater depletion in the UAS. • Climate variability can intensify low flow regimes and increase water demand. [ABSTRACT FROM AUTHOR]

Sea cucumbers are important ecological engineers in marine ecosystems. However, the fishery demand of some species, especially large-epifaunal and commercially used (LEC) sea cucumbers, has risen drastically, resulting in serious depletion of local populations for many species. Despite this problem, basic ecological data on sea cucumbers, such as population densities and preferred habitats, are often still insufficient. Here, we report on the population densities of multiple LEC sea cucumber species, and their ambient benthic communities at eight sites around Okinawa Islands. Further, we discuss the correspondence between sea cucumber densities and the surrounding coral communities. Our results show two sites within national or quasi-national parks, Aka and Manza, where stricter rules have been placed on fisheries and land reclamation compared to other areas, had the highest and third highest sea cucumber population densities among sites, respectively. Holothuria atra was observed at all survey sites and made up the majority of sea cucumber populations at all sites except for Chatan and Sesoko, where Holothuria leucospilota and Stichopus chloronotus were most abundant, respectively. Regarding the relationships between benthic composition and LEC sea cucumber species, S. chloronotus was significantly correlated with dead corals, scleractinian corals, and coralline algae. As well, H. leucospilota had significant correlations with rubble. Although there were no significant correlations between any specific scleractinian coral genus and sea cucumber densities, S. chloronotus was marginally insignificant with Platygyra and Psammocora. Notably, medium- to highly valued species were sparse in our surveys, and most of them appeared at only one site. Additionally, at one site (Odo), only three LEC sea cucumber individuals were observed. Combining these facts with relatively low population densities around the Okinawa Islands compared to densities reported in previous research from the Indo-West Pacific Ocean region, we conclude that Okinawan LEC sea cucumber populations have been and are being impacted by high levels of direct (e.g., overexploitation, as well as coastal development) and indirect anthropogenic pressure (e.g., decreasing water quality). To address the current situation, repeated monitoring and more detailed investigations to reveal the drivers that determine LEC sea cucumber species aggregations and population densities are urgently needed, along with more robust management of remaining LEC sea cucumber populations. [ABSTRACT FROM AUTHOR]

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Archived logbooks detailing landings at Scottish shore‐based whaling stations between 1903 and 1951 were used to map whale catch locations. Historical distribution and occurrence are inferred and summary statistics on total landings are updated for blue (Balaenoptera musculus), fin (Balaenoptera physalus), humpback (Megaptera novaeangliae), North Atlantic right (Eubalaena glacialis), sei (Balaenoptera borealis) and sperm (Physeter macrocephalus) whales: a total of 9,996 whales were caught during this period, which is 3.7% higher than previously reported and 25% higher for blue whales.The most frequently caught species were fin and sei whales. Whaling off Scotland in the 1920s contributed to the likely extinction of right whales in the eastern North Atlantic. Blue whales, once regularly hunted to the west of Scotland, are now rarely documented there and North‐east Atlantic whaling appears to have had a significant and lasting impact on sei whales.Analysis of whaling effort indicates that catch rates remained high despite the depletion of some species. This, may be a consequence of two features of Scottish shore‐based whaling: (1) the mixed species catch composition; and (2) the catching of whales as they migrated through Scottish waters.The findings of this study highlight the historical significance of the shelf‐seas around Scotland as a habitat for some species, which was not apparent from previous studies. These results can inform where there may be potential for the recovery of some species in the future.Current major threats in the North Atlantic include entanglement, ship strike and displacement owing to the effects of climate change. The baseline and historical information on distribution and seasonal occurrence examined here is important for informing spatial and temporal measures to reduce these threats. If populations are to recover post‐whaling there is an increasing need to reduce threats such as ship strikes and entanglement, whose magnitude is proportional to whale density. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Groundwater constitutes the main source of water in the province of Ciego de Ávila, Cuba; especially in agriculture, which occupies the main economic line, however the overexploitation of aquifers in the southern basin of the province puts the sustainability of this important resource at risk, which is renewed through the natural recharge of rainfall. Objective: To determine the relationship between precipitation and groundwater levels in the hydrogeological sectors CA-II-2 and CA-II-3 of the Ciego de Ávila South Basin, which can constitute a way for the efficient use of water for irrigation purposes in this area of ​​great agricultural importance. Methodology: In the development of the research, different methodologies were used: selection of the most representative rain gauges, calculation of effective precipitation, determination of accumulated monthly and annual rainfall; as well as the annual rainfall of the wet and dry periods, completion of rainfall series by the linear regression method, use of the HidroEsta 2 program to obtain the mean hiperanual rainfall and the historical mean levels, absolute minimum and maximum of all the selected wells. The mean rainfall of the area of ​​the sectors was determined with the Isohyet method and the charts of hiperanual limnigrams were constructed using the BARHIS software. Results: The investigation showed that the average rainfall in the area is 1303.6 mm, higher than the historical average for the province. The water levels in the aquifer range between 0.84 and 12.98 m; where 7.21 m is the absolute average value. The year 1988 had great variations in rainfall, levels and the exploitation of groundwater. This study suggests the need to take measures that contribute to the rational use of groundwater in this overexploited basin due to the intensive use of water resources in agricultural irrigation. Conclusions: The study carried out was able to verify that the average rainfall in the area is 1303.6 mm, higher than the historical average for the province. The water levels in the aquifer range between 0.84 and 12.98 m, with absolute averages of 6.52 and 7.21 m respectively. The year 1988 presented high variability in rainfall, underground levels and the exploitation of groundwater.

The Mediterranean coastal aquifer system of the Grombalia basin (NE Tunisia) offers immense potential as a source of fresh water for agriculture, industry, and drinking water supply. Nonetheless, due to its intricate hydrogeological characteristics and the prevailing issue of groundwater salinity, comprehending its groundwater system behavior becomes crucial for the effective and sustainable management of this aquifer system. Based on the hydrogeological characterization of the Grombalia basin, a novel 3D hydrogeological conceptual model was developed to enhance the understanding of its complex aquifer system. The integration of insights from geological, hydrogeological, hydrodynamic, and hydrochemical components facilitated the construction of the hydrogeological conceptual model. Although the model’s validity faced initial uncertainties due to spatial interpolation of lithological sequences, this study’s thorough and encompassing hydrogeological investigation overcame these limitations. As a result, a more informed comprehension of the aquifer system complexities was achieved. This study reveals that the basin is underlain by an extensive, cohesive Mio–Plio–Quaternary aquifer system. The model demonstrates vertical and lateral hydrogeological continuity between the Quaternary and underlying Mio–Pliocene deposits, enabling groundwater flow and exchange between these layers. Over-abstraction of the Mio–Plio–Quaternary aquifer system has led to a significant drop in piezometric levels and raised the risk of seawater intrusion. These findings emphasize the critical necessity of taking into account the interconnections among hydrogeological units to ensure sustainable groundwater management. The developed conceptual model offers a key tool for understanding the hydrodynamic functioning of the Grombalia aquifer system with a view toward guiding future groundwater management strategies. The application of this approach in the Grombalia basin suggests its potential applicability to other regional aquifers facing comparable challenges.

Context: Shark and ray fisheries in the southern Gulf of Mexico (GOM) are multispecific and use diverse fishing gear in multiple coastal areas. Aim: Because no catch and fishing effort records by species exist, the aim of this study was to estimate the species' vulnerability to fisheries through limited-data assessment methods. Methods: The vulnerability to 14 fisheries through the productivity and susceptibility analysis (PSA) and rebound-potential method were estimated for 14 elasmobranchs. Key results: Carcharhinus falciformis , Carcharhinus plumbeus and Sphyrna lewini among sharks, besides Hypanus americanus and Aetobatus narinari among rays, had the highest vulnerability and the lowest rebound potential. The sensitivity tests showed that the most significant differences in cumulative vulnerability (Cv) occur between two alternative widely applied PSA approaches. Cv determined from scores averaged over a range of susceptibility attributes tends to be higher than the product of the scores of four standard susceptibility attributes. Conclusions: Significant correlations between Cv of Approach 1 and rebound-potential scenarios were estimated, indicating a general pattern in which the species' rebound-potential increases while the vulnerability decreases. Implications: The correlation between Cv (Approach 1) and rebound-potential highlights the suitability of PSA when enough information is available on the interactions of fisheries and populations. Vulnerability of elasmobranchs to multiple fisheries was estimated through the productivity and susceptibility analysis (PSA) and rebound potential method. Among sharks and rays, the silky shark, sandbar shark and scalloped hammerhead, and southern stingray and spotted eagle ray had the highest vulnerability and the lowest rebound potential. In addition, significant correlations between rebound potential and the cumulative vulnerability of the approach that averaged susceptibility attributes were estimated, indicating a general pattern in which the species' rebound potential increases while the vulnerability decreases. [ABSTRACT FROM AUTHOR]

China is the biggest fish producing country in the world. Its marine waters are frequently declared as over-harvested. Therefore, accessing the exploitation status of commercial fishery resources becomes very important for their proper management. This study uses catch statistics, 2007-2018, of a vital fishery resource, viz., Ammodytes personatus (Girard, 1856) to know its stock status and ongoing economic implications. For this purpose, Surplus Production Models (SPMs) were applied to the data through two world famous fishery routines, viz., Catch and Effort Data Analysis (CEDA) and A Stock Production Model Incorporating Covariates (ASPIC). In CEDA, we applied two SPMs, viz., Fox, Schaefer and Pella Tomlinson Models abbreviated as FM, SM and PTM, in that order. On the other hand, in ASPIC, we sued two SPMs, viz., FM and Logistic Model (LM). For principle IP 0.9, CEDA calculated MSY in a range between 13500 t and 30500 t whereas the estimates of ASPIC remained between 71500 t and 85000 t. Maximum sustainable yield (MSY) estimates are considerably lower than recent catch statistics which evidently indicates overexploitation. It is suggested that the target catch of this fishery resource should be between 14000 t and 20000 t. Moreover, it is highly recommended to conduct further more comprehensive and detailed studies on A. personatus fishery resource as this study is just a first step. [ABSTRACT FROM AUTHOR]

This study aimed to determine the age and growth parameters of the African catfish Clarias gariepinus (Burchell, 1822) from the Asi River. A total of 185 fish samples have been collected from the Asi River, located in the Eastern Mediterranean region of Turkey, from December 2018 to March 2019. Samplings were carried out with fyke-nets. Lengths and weights of samples ranged from 20.47 to 62.46 cm and 74.4 to 1874.2 g, respectively. The sex ratio (1:1.06) was biased toward males (p>0.05). In terms of length-weight relationship, b-values were calculated as 2.98, 2.83, and 2.94 for female, male, and whole samples, respectively. Isometric growth was determined. The Fulton condition factor (CF) value for all samples was calculated as 0.7591±0.009. The ages of fish samples ranged from I to IV, and the dominant age and total length (TL) groups of the population were the I and II age groups. The von Bertalanffy growth parameters were estimated as L∞=58.5 cm, K=0.41 year-1, t0 = -0.7, Φ'=3.15 for females; L∞=68.3 cm, K=0.35 year-1, t0 = -0.6, Φ'=3.21 for males and L∞=58.2 cm, K=0.39 year-1, t0 = -0.4, Φ'=3.12 for whole collected samples. As a result, climate change and its effects, especially the construction of dams in certain parts of the river for agricultural irrigation purposes and the resulting lack of management negatively affect the natural living stocks of the Asi River. Therefore, it can be said that the C. gariepinus stocks in these areas are overexploited. Legal arrangements should be made in this region to correct these conditions. [ABSTRACT FROM AUTHOR]

The aim of this article is to present the multidimensional challenges associated with the exploitation of small pelagic fish in the West Africa region. The method involved collecting statistical data on the production and trade of these fish from research centres located in countries along the West African coastline. Field surveys were also conducted with experts and key stakeholders in fisheries to gather qualitative information on fisheries resource governance and working conditions within the value chain. These empirical data are enriched by a narrative review of scientific literature. Our results show an average annual production of small pelagic fish estimated at 1.3 million tonnes. Although this performance has improved over the past decade, primarily due to increased catches in Mauritania, it remains insufficient to meet the needs of a rapidly growing population. Indeed, per capita consumption of small pelagic fish has decreased by two kilograms over the past decade, currently standing at five kilograms per individual per year. The trade deficit in pelagic fish is increasing. This situation is set to worsen in the coming years due to various factors such as the current state of overexploitation of pelagic stocks, degradation of marine ecosystems, and climate change. Additionally, the emergence of fishmeal and fish oil industries, as well as the lack of adequate port infrastructure, hampers the value addition of the small pelagic fish value chain for human consumption. On the governance front, several challenges remain. Current public policies are often directive and ineffective, particularly concerning artisanal fisheries. The management of migrant fishers also remains problematic, exacerbating the pressure on already vulnerable stocks. Despite the establishment of regional institutions, interviews with experts highlight a lack of integration and synergy in fisheries resource governance. In a context where issues of food security and climate change are becoming increasingly urgent, it is imperative to design and implement robust regional strategies to address these critical challenges.Haut du formulaire Bas du formulaire • The study analyses the multidimensional challenges facing West African fisheries. • The article highlights the need for local stakeholder integration in decision making. • The study offers a comprehensive diagnosis as a basis for targeted interventions. • Criticism of small pelagics management and a call for strong regional policies. • The study links regional analysis to global food security and climate change issues. [ABSTRACT FROM AUTHOR]

The paper aims to provide a postdictive answer to why Central Asia is continuously investing or aspiring to invest in irrigation infrastructure and further contributing to the overexploitation of renewable and non-renewable endowments of its steppe zones even when the conventional economic rationale loses its worth. The study devises its analytical framework around the Hungry Steppe case. The analyses explain such instances with the sunk-cost effect resulting from complexity investments as part of a positive feedback loop that eventually locked the Steppe in the intensive cropping system and land degradation. The paper justifies the discourse of the sunk cost role in the Hungry Steppe lock-in phenomenon using game modelling. The work presents two alternative scenarios based on its game-theoretic model. Both scenarios reveal that most strategic interactions between the State and resource users are subject to multiple equilibria under both bureaucratic and private arrangements. Though the private arrangement scenario expects better infrastructure, both keep locking the Steppe in the positive feedback loop of land degradation and intensive cropping. The paper provokes the discourse on alternatives to intensive cropping in the Steppe, suggesting the collapse of irrigated agricultural production practices to solve the vicious cycle of resource over-exploitation.

Abstract Determining the dynamics and sustainability of human interactions with threatened species is essential to inform evidence‐based conservation, but data can be challenging to collect across large areas and multiple user groups. Chinese giant salamanders Andrias spp. are critically depleted across China. Wild populations were exploited during the 20th century, and more recently to support a large‐scale farming industry. However, robust data remain largely unavailable on the timing of population declines in relation to changing human pressures, on primary drivers of exploitation, or on the effectiveness of conservation legislation. We conducted a series of large‐scale interview surveys across the range of giant salamanders in China, targeting potential rural and urban user groups, and stakeholders involved with giant salamander exploitation and policy management (comprising 2,932 rural households, 66 salamander farms, 115 county government officials and 835 urban consumers). Giant salamander populations were probably declining from at least the 1980s due to exploitation for food, and negative cultural values associated with these animals have not prevented rural consumption. There has been a major escalation in exploitation following the establishment of a large‐scale giant salamander farming industry in the 2000s. Our results demonstrate wide‐scale and largely unregulated illegal hunting to stock farms at a country‐wide scale in order to support demand by urban consumers for high‐prestige rare meat. We estimate there were at least 42,000 wild‐caught breeding adult giant salamanders and 164,000 wild‐caught subadults in farms across China at the time of our survey. Salamander farming probably poses unsustainable pressure on giant salamander populations. Existing legislation has clearly proved ineffective at preventing the stocking of farms with wild‐caught animals, and our findings highlight an important gap in the effectiveness of China's conservation protection for some of its highest‐priority threatened species. Tackling this problem will likely require multiple coordinated approaches, including enforcement of legislation, increased penalties for removing giant salamanders from the wild, permanent identification of captive‐bred giant salamanders, and consumer‐focused interventions to reduce urban demand. A free Plain Language Summary can be found within the Supporting Information of this article.

Abstract Sidi Bel Abbes plain, in Western Algeria, covers an area of 813 km2 and holds an important groundwater reservoir, providing the region with a large water potential. It displays characteristics of a peri-urban aquifer, with a large agricultural sector. The climatic variations that affected this region, the development of industrial and agricultural activities along with the over-exploitation of the groundwater resource negatively impact the aquifer's hydrodynamic balance. This work is structured around a multiapproach process based mainly on geophysical data to determine the reservoir bathymetry, rainfall data, humidity data using the standardized precipitation index (SPI), piezometric maps, hydrodynamic data, and groundwater extraction rate. Results revealed a significant decrease in humidity values over time. This negatively influences the water potential of the alluvial aquifer and induces a lateral recharge from adjacent aquifers (overfilling). Indeed, the rainfall contribution to the recharge appears low compared to that of the surrounding aquifers. However, total annual rainfall above 500 mm/year may reduce the input of the adjacent aquifers. Besides, our study indicates a well-defined hydrodynamic pattern in the alluvial aquifer, due to the bowl-shaped bedrock of the aquifer and the excessive overexploitation, especially downstream (the region of Sidi Bel Abbes). Thus, this aquifer adapted to such exploitation, through continuous and systematic recharge of drainage flows by the upstream groundwater (regions characterized by a wall uplift). The aquifer’s pluviometric dependence occurs clearly in its south-western part. A 50% humidity value implies a 0–10 m increase in the water table.