Search

The large yellow croaker, an endemic migratory species in China's coastal waters, holds considerable economic importance. It is very necessary and significant to study the spatio-temporal evolution of large yellow croaker fishery based on environmental factors. In this paper, the HY-1C/D Coastal Zone Imager was applied to reveal distributional details of suspended sediment concentration and chlorophyll-a concentration in large yellow croaker fishery. Furthermore, combined with multi-source data, the characteristics of other environmental parameters such as temperature, salinity, current, wind and fronts were analyzed to reveal the changing of large yellow croaker fishery location. The results show that: (1) The environmental factors of large yellow croaker fishery exhibit pronounced spatial and temporal characteristics. Generally, the temperature (9-28°C), salinity (20-34 ‰) and other water environmental factors of the fishing ground are conducive to the survival and growth of large yellow croaker. The formation and change of fishery are closely related to environmental factors in the water. (2) The change of environmental factors in the water may induce the change of large yellow croaker fishery location. Winter sea surface temperature has significantly risen over the past two decades (2004-2023). With the sea surface temperature rising by approximately 2°C west of 125°E, the overwintering ground has expanded westward, increasing by nearly 29%. In addition, the scale and number of offshore windmills increased by 836% and 456% respectively over the decade (2013-2023). In 2023, offshore wind farms cover an area of 145.47 km2 and have 200 windmills. Wind turbine piles resembling artificial reefs. It can not only promote the waters vertical exchange to enhance the nutrients in upper waters but also provide a protective base for fish spawning. Thus, effectively attracting fish species. The construction of offshore wind farms has extended spawning ground north-westward to the mouth of the Yangtze River Estuary, expanding by nearly 21%. This study improved the cognition level of resources, habitat environment and change trend of large yellow croaker. It also provided technical support for the construction and protection of the large yellow croaker fishery. [ABSTRACT FROM AUTHOR]

A large-scale aquaculture of shrimp and crab ponds can be found with a high demand for automatic feeding in China. Automated feeding is crucial to the output and quality of cultivated species, due to cost savings and minimum pollution of aquaculture water bodies. It is also one of the most critical steps to enhance the efficiency of shrimp and crab pond aquaculture in mechanization and automation. Given the limited swimming ability of shrimp and crabs, it is essential to evenly distribute feed throughout the pond, according to their feeding behaviors. Previous research has been increasingly focused on the automatic feeding boats of shrimp and crab ponds, particularly on precise positioning, uniform feeding, automatic navigation, and operation. In this study, a research survey was implemented on the feeding boats for the shrimp and crab ponds in the world. Subsequently, the current research status of automatic feeding boats was outlined for the shrimp and crab ponds. Three key aspects were: the propulsion system of feeding boats, the bait delivery mechanism, and precise feeding control technology. Firstly, the current propulsion systems of feeding boats were primarily paddle wheels and propellers, each of which shared their own strengths and weaknesses suitable for different scenarios. Structural optimizations were conducted to improve the speed, efficiency, and maneuverability. Additionally, the blowers and integrated screw systems were explored for feeding boats, in response to the aquaculture environment with dense aquatic plants. However, two mechanisms were still in the exploratory phase. Secondly, the feeding and scattering mechanisms were designed to achieve the transportation and scattering of feed under various aquaculture conditions. 1) The feeding mechanism mainly included a screw, rotary valve, and vibrating feeding. The lower feed breakage rates and higher transportation speeds were achieved for the high efficiency and accuracy. 2) The scattering mechanism was primarily used as centrifugal scattering discs, particularly for a wide scattering range. Some optimizations were also implemented to achieve higher uniformity in the scattering and lower feed breakage rates using various simulation software. According to the feeding characteristics of shrimp, direct feeding was applied in shrimp ponds. Thirdly, the precise feeding control technology focused mainly on three aspects: 1) According to different breeding needs, path planning involved planning edge-following and coverage paths using a combination of sensors, satellite navigation systems, and path planning. 2) Automatic recognition was used for shrimp and crabs using machine vision and acoustic technology. The feeding boat was formulated feeding strategies, according to their distribution within the aquaculture pond. 3) Precise control was carried out to predict and accurately adjust the amount of feed using deep learning. Furthermore, the limitations of current research were examined to predict future trends: 1) To enhance adaptability and operational reliability in complex environments, 2) To investigate the interaction mechanism among feed particles, feeding boats, and breeding organisms, 3) To improve precision performance using artificial intelligence technologies, and 4) To realize the standardization and systematization. From the perspective of practical application, an emphasis was put on the standardizations of equipment layout, pipeline distribution, and waterweed planting. The findings can offer valuable insights for further research, development, and promotion of automatic feeding boats for shrimp and crab ponds in China. [ABSTRACT FROM AUTHOR]

Sea urchin roe is a high-quality product in terms of its nutritional value, valuable biochemical composition, and acquired taste. Urchin stocks, however, have been overfished worldwide and new candidates for commercial harvesting and aquaculture are required to satisfy the demand from the expanding market. The green sea urchin Strongylocentrotus droebachiensis from Russian waters of the Barents Sea may be considered a new source for potential consumers. We summarized available information regarding distribution patterns, feeding, reproduction, and growth as well as studies focused on farming of this species to assess the fishery and aquaculture potential of the area. This species is abundant in the coastal zone where it is commonly associated with laminarian kelp. The brown algae Saccharina latissima is the primary diet for S. droebachiensis but it also consumes animal foods. Red king crabs are the main predators for sea urchins but they do not significantly affect the S. droebachiensis population. A spawning peak of S.droebachiensis is registered in March–April. Green sea urchins reach a commercial size of 50 mm diameter at age 6 and the estimated stock of commercial urchins is 50,000–81,000 t. The most promising sites for harvesting are Varanger-fjord and Bolshoy Oleniy Island plus Porchnikha Bay. The best harvesting seasons are February–March and September–October. Sea-based rearing systems appear to be the most suitable approach for sea urchin aquaculture based on grow-out of adult animals fed on algal or mixed diets. [ABSTRACT FROM AUTHOR]

The wave of digital development is sweeping across the globe today, exerting profound impacts on various aspects of human society. As an important industry in the national economy, it is worth studying whether the sustainable development of fisheries is influenced by digitalization. Based on this, taking the fishery development in 30 provinces of China from 2011 to 2021 as an example, this article examines how digitalization affects fishery sustainable development, and conducts an expansive study on the fishery regional innovation capacity. The article finds that Chinese fishery digitalization accelerates fishery sustainable development by promoting technological progress and enhancing technological efficiency, and this promotion effect exhibits different characteristics due to varying levels of fishery sustainable development and regional disparities. Furthermore, the exploratory analysis reveals that as the fishery regional innovation capacity improves, the promoting effect of fishery digitalization on sustainable development gradually strengthens. This article has great significance in theory and reality for guaranteeing food security and realizing fishery sustainable development. [ABSTRACT FROM AUTHOR]

The withdrawal of the United Kingdom from the European Union will likely result in reduced fishing grounds for the Belgian fishing fleet. This fleet now targets demersal fish, but there used to be a tradition of catching Atlantic herring (Clupea harengus). After the stock collapse of Atlantic herring in the 1970s, fishing on herring by the Belgian fleet did not recover and herring quotas are now exchanged with the Netherlands and Germany. To assess the feasibility of reintroducing herring fisheries for the Belgian fishing fleet, our study created spatiotemporal species distribution models for Atlantic herring in the Northeast Atlantic Ocean, focusing results on the Belgian Part of the North Sea. In total 30078 occurrence records were derived and processed to fit species-environmental relationships with temperature, salinity, seabed characteristics and plankton concentration using Maximum entropy (Maxent) models. The Area Under the Curve of the Receiver Operating Characteristic plot (AUC) and the True Skill Statistic (TSS) were used to assess model fit. Models performed well (AUC > 0.7 and TSS > 0.6). While a broad spatiotemporal distribution of Atlantic herring in the Northeast Atlantic Ocean was inferred, regional differences show that herring habitat is most suitable during winter months in the Belgian Part of the North Sea for both adult and larval herring (habitat suitability index > 75%). This regional trend in the Belgian Part of the North Sea was negatively correlated (R = -0.8) with the North Atlantic Oscillation (NAO). We anticipate that these findings will provide valuable insights for policymakers to implement sustainable fisheries management practices. [ABSTRACT FROM AUTHOR]

ABSTRACT The Atlantic surfclam, Spisula solidissima supports a lucrative commercial fishery in the Mid‐Atlantic Bight (MAB) worth roughly $30 million in revenue per year. Rapid climate change is expected to modify the geographic range of the Atlantic surfclam, with consequences for the surfclam fishery. This study evaluated fishery‐based indicators projected from 2020 through 2095 based on anticipated changes in the geographic range and biomass of the Atlantic surfclam, using a Spatially Explicit, agent‐based Fisheries and Economics Simulator (SEFES). Simulations generally showed a positive trend in Atlantic surfclam biomass throughout the next three‐quarters of the 21st century as the clam's range continues to shift offshore and northward along the continental shelf. A general decrease in fishing mortality rate is projected given the present fleet capacity, with a simultaneous increase in catch and landings per unit effort (LPUE), signaling future potential growth in the surfclam fishery. Regionally, forecasts show biomass expanding into deeper waters particularly off New Jersey, Long Island, and southern New England starting in the early 2050s, whereas populations on Georges Bank and off Delmarva gradually decline. Trends in time spent fishing, catch, and LPUE parallel those of biomass in each region. These results can inform managers and business interests that rely on this fishery, as well as other users of the continental shelf, to provide a basis for the development of anticipatory management for the socio‐ecological and economic impacts that may result from future changes in the Atlantic surfclam range and carrying capacity consequent of climate change. [ABSTRACT FROM AUTHOR]

Failure to consider population structure when managing harvested fishes increases the risk of stock depletion, yet empirical estimates of population structure are often lacking for important fishery species. In this study, we characterise genetic variation in single nucleotide polymorphisms (SNPs) to assess population structure for three harvested species of tropical snappers across the broad (up to 300 km wide) and extensive (~ 4000 km) continental shelf of north-western Australia. Comparisons across ~ 300 individuals per species, showed remarkably similar patterns of genetic structure among Lutjanus sebae (red emperor), L. malabaricus (saddletail snapper) and Pristipomoides multidens (goldband snapper) despite subtle differences in biological and ecological traits. Low levels of genetic subdivision were reflected in an isolation by distance relationship where genetic connectivity increased with geographic proximity. This indicates extensive but not unlimited dispersal across the north-western Australian shelf. Our findings provide evidence of connectivity between current management areas, violating the assumption of multiple independent stocks. Spatial stock assessment models may be more suitable for the management of these species however demographic connectivity rates cannot be accurately estimated from the conventional population genetic approaches applied in this study. We recommend that managers aim to maintain adequate spawning biomass across current management areas, and assess stocks at finer scales, where practical. [ABSTRACT FROM AUTHOR]

Grimothea monodon, an important fishery resource in the Humboldt Current marine ecosystem (HCE), present two contrasting morphotypes (PM, pelagic morphotype; BM, benthic morphotype). The fishery management of G. monodon is focused on understanding only fishery aspects that apply to a limited area, and there are currently no studies that evaluate the nutritional status of these morphotypes. This study evaluated the biological performance of PM and BM, analyzing the body (size, CL; weight, W; condition factor, Kn) and biochemical condition (glucose, G; proteins, P; lipids, L; fatty acids, FAs). The results reveal that G. monodon showed differences in CL and W between morphotypes, with higher values in BM than PM. The Kn was different between morphotypes with a tendency of isometric growth. In turn, the G contents were higher in PM than BM, while the contents of P, L, and FAs showed an opposite tendency, with higher contents recorded in BM than PM. Our findings suggest that the Kn should be included to strengthen the biological parameters and their relationships used in fishery management models. Differences in the biochemical condition between morphotypes can be considered potentially adaptive, in response to the combined effect of environmental factors that vary in the HCE. [ABSTRACT FROM AUTHOR]

Context: The blackspot shark (Carcharhinus sealei) is a small-bodied coastal shark often incidentally caught in fisheries across South-east Asia. Aims: This study aimed to document the species' biology, ecology, fisheries and markets to inform conservation. Methods: In total, 103 blackspot sharks from Indonesia (n = 101) and Singapore (n = 2) were examined to determine biological parameters (growth rate, age at maturity, reproductive traits and diet). An interview with a Singaporean seafood supplier gave insight to population trends, fisheries and markets. Key results: Males attained a maximum age of 9 years, the smallest mature individual measured 709-mm stretched total length (STL), with 50% reaching maturity at 6.15 years. Females attained a maximum age of 11 years, the smallest mature individual measured 730 mm STL, with 50% reaching maturity at 6.12 years. The species has an overall growth rate (k) of 0.37 year−1. Reproduction was asynchronous, with only two pups produced per litter. Crustaceans dominated the diet of juveniles, whereas bony fishes and cephalopods dominated the diets of adult males and adult females respectively. Conclusions: Blackspot sharks have a moderately fast growth rate, but a late age-at-maturity and a low fecundity. Diet differed between the sexes as well as adults and juveniles. Implications: The low fecundity and late maturity of blackspot sharks increase their vulnerability to exploitation. Blackspot sharks are now listed on CITES-Appendix II, but mortality may remain high because they are reportedly often caught incidentally. Blackspot sharks from Riau Islands, Indonesia, have a late maturity (~6 years old) and low fecundity (litters of two pups). Mature males primarily eat bony fishes, mature females primarily eat cephalopods, whereas juveniles primarily eat crustaceans. A seafood supplier who was interviewed has perceived population declines and stated that the species is mostly caught incidentally. [ABSTRACT FROM AUTHOR]

Abstract Failure to consider population structure when managing harvested fishes increases the risk of stock depletion, yet empirical estimates of population structure are often lacking for important fishery species. In this study, we characterise genetic variation in single nucleotide polymorphisms (SNPs) to assess population structure for three harvested species of tropical snappers across the broad (up to 300 km wide) and extensive (~ 4000 km) continental shelf of north-western Australia. Comparisons across ~ 300 individuals per species, showed remarkably similar patterns of genetic structure among Lutjanus sebae (red emperor), L. malabaricus (saddletail snapper) and Pristipomoides multidens (goldband snapper) despite subtle differences in biological and ecological traits. Low levels of genetic subdivision were reflected in an isolation by distance relationship where genetic connectivity increased with geographic proximity. This indicates extensive but not unlimited dispersal across the north-western Australian shelf. Our findings provide evidence of connectivity between current management areas, violating the assumption of multiple independent stocks. Spatial stock assessment models may be more suitable for the management of these species however demographic connectivity rates cannot be accurately estimated from the conventional population genetic approaches applied in this study. We recommend that managers aim to maintain adequate spawning biomass across current management areas, and assess stocks at finer scales, where practical.

State of stocks and fishery and some general features of biology are considered for saffron cod in the Bering Sea on results of bottom trawl surveys and commercial fishery statistics in 2000–2023. In 2023, the stock in the southwestern part of the sea is estimated in 114 . 103 t, in the northwestern part — in 20 . 103 t, and at the coast of Chukotka Peninsula — in 0.14 . 103 t. The average annual catch of saffron cod in the southwestern and northwestern parts of Bering Sea is amounted in 8.5 . 103 t and 1.1 . 103 t, respectively. The saffron cod fishery at Chukotka is absent.

With the collapse of global populations, New Zealand has one of the last wild abalone fisheries. The blackfoot abalone (Haliotis iris) supports important customary, commercial and recreational harvests, but environmental stressors and overfishing have prompted restoration and stock enhancement efforts. We used field surveys to quantify effects of the 2018 commercial outplanting of 167,000 hatchery-raised juvenile abalone following the catastrophic Kaikōura earthquake. We tested alternative enhancement methods by outplanting swimming larvae and rocks with settled post-larvae. Annual surveys at seven sites found that outplanted juveniles comprised 12% of the sampled population after three years, amid unexpectedly high natural recruitment. Recaptured outplants grew well at c. 25 mm yr−1 but showed poor growth at two densely populated sites. After three years, >50% of recaptured individuals had likely reached sexual maturity. Outplanting 200,000 competent swimming larvae into natural habitats had no effect after three months compared to controls. However, the outplanting of rocks settled with larvae resulted in a significantly greater density of small (≤15 mm) recruits compared to controls, signalling potential for this method as a practical and scalable enhancement strategy. The insights from this research help clarify the benefits and limitations of three stock enhancement methods and inform future efforts. [ABSTRACT FROM AUTHOR]

This study aims to analize the meaning, the decision making and the identification of fishery small entreprise investment. The study locates in Tuban Coastal–East Java Indonesia. It employs qualitative methods with case study. The data are collected through semi-structural interview, observation, and documentation. Techniques and time triangulation are used to check the validity of the data. CV. SAM is a fishery business on aquaculture of shrimp (vanname sp) and catfish (clarisas batracus sp), also makes probiotic and vitamins for fishes. The result shows that the entrepreneur interprets an investment as purchasing an asset to operation the entreprise. The owner decides on an investment for the purpose of expanding business and taking opportunity on the potential big market. Nevertheless, the enterprise identification several risks on their business. Firstly, operational risk; there are fish disease and increasing price of the feed and medicine on vanname that decreasing profit. Secondly, market risk; there are rejection or decline of selling price if the quality on low standart especilly for vanname on foreign markets. The entreprise anticipates operational risk by producing probiotics and vitamins for fish. On the market risks, the entrepreneur hasn’t any action to anticipate and to find solution especially for vanname. To develop the fishery small enterprise, the stakeholders need to support them in getting solution.

Background: Studying habitat use and vertical movement patterns of individual fish over continuous time and space is innately challenging and has therefore largely remained elusive for a wide range of species. Amongst sharks, this applies particularly to smaller-bodied and less wide-ranging species such as the spurdog (Squalus acanthias Linnaeus, 1758), which, despite its importance for fisheries, has received limited attention in biologging and biotelemetry studies, particularly in the North-East Atlantic. Methods: To investigate seasonal variations in fine-scale niche use and vertical movement patterns in female spurdog, we used archival data from 19 pregnant individuals that were satellite-tagged for up to 365 days in Norwegian fjords. We estimated the realised niche space with kernel densities and performed continuous wavelet analyses to identify dominant periods in vertical movement. Triaxial acceleration data were used to identify burst events and infer activity patterns. Results: Pregnant females frequently utilised shallow depths down to 300 m at temperatures between 8 and 14 °C. Oscillatory vertical moments revealed persistent diel vertical migration (DVM) patterns, with descents at dawn and ascents at dusk. This strict normal DVM behaviour dominated in winter and spring and was associated with higher levels of activity bursts, while in summer and autumn sharks predominantly selected warm waters above the thermocline with only sporadic dive and bursts events. Conclusions: The prevalence of normal DVM behaviour in winter months linked with elevated likely foraging-related activity bursts suggests this movement behaviour to be foraging-driven. With lower number of fast starts exhibited in warm waters during the summer and autumn months, habitat use in this season might be rather driven by behavioural thermoregulation, yet other factors may also play a role. Individual and cohort-related variations indicate a complex interplay of movement behaviour and habitat use with the abiotic and biotic environment. Together with ongoing work investigating fine-scale horizontal movement as well as sex- and age-specific differences, this study provides vital information to direct the spatio-temporal distribution of a newly reopened fishery and contributes to an elevated understanding of the movement ecology of spurdog in the North-East Atlantic and beyond. [ABSTRACT FROM AUTHOR]

Mangrove clam is the most sought-after bivalve in the Philippines due to its taste, size, and nutrition. Due to its economic importance, this paper aims to determine the population dynamics of mangrove clam P. philippiana harvested in gleaning sites in the Davao region using the FAO ICLARM Stock Assessment Tool (FISAT II). A total of 2493 clams collected from December 2018-December 2020 with sizes ranging from 14-84 mm SL and 2.2-178.6 g were classified according to size classes with 5 mm intervals. The length-weight relationship was computed and showed negative allometry (a = 0.002, b = 2.6205, R² = 0.89). The estimated growth parameters using ELEFAN I was L∞ = 98.64 mm, K = 1.33 year-1, t0 = -1.07. Length converted catch curve routine estimated Z = 10.27year-1, M = 1.52 year-1, F = 8.75 year-1, E = 0.85, and backward extrapolation generated Lc50 = 34.83 mm SL which is below Lm = 65.76 mm SL. Recruitment patterns were highest during July and August 2020, and VPA showed a high F at 60 mm SL. Beverton and Holt Y/R analysis showed E0.5 = 0.328 and Emax = 0.551, yield isopleths derived from plotted Lc50/L∞ = 0.353 and E = 0.85 values were within quadrant D. The result revealed that Lm>Lc50 implies that mangrove clams gleaned in the area were small and immature. Moreover, F>Fopt and E>Emax and E>E0.5 suggest that mangrove clam fishery in the region was heavily exploited. The study concluded that the mangrove clam Pegophysema philippiana was overexploited and that a management strategy was needed in the Davao Region, Philippines. [ABSTRACT FROM AUTHOR]

The BBNJ Agreement, adopted on June 19, 2023, is considered to be the third implementation agreement of the United Nations Convention on the Law of the Sea after the 1994 Part XI Implementation Agreement and the 1995 High Seas Fisheries Agreement. Of the four themes of the BBNJ Agreement, namely marine genetic resources, area-based management measures, environmental impact assessment, and capacity building and technology transfer, only the part relating to marine genetic resources is explicitly excluded from the scope of the BBNJ Agreement. There are no explicit exclusions in relation to area-based management measures and environmental impact assessments. Therefore, the sections on area-based management instruments and environmental impact assessments may conflict with fisheries issues in other international fisheries instruments during the implementation of the BBNJ Agreement. Although the BBNJ Agreement has a so-called "not-undermine" provision to ensure that it does not conflict with international fisheries instrument represented by the United Nations Convention on the Law of the Sea, the 1995 High Seas Fisheries Agreement, and regional fisheries management organizations, it cannot be ruled out that the BBNJ Agreement may conflict with regional fisheries organizations' area-based management measures and environmental impact assessments. However, the potential for conflicts also implies the potential for developmental outcomes if they are harmoniously interpreted and implemented. First of all, the emergence of the BBNJ Agreement as a comprehensive treaty covering the high seas and the Area provides an opportunity to build an integrated mechanism for international fisheries insturments that were previously fragmented by regions and species. In addition, the BBNJ Agreement can establish a cooperation system with existing regional fisheries management organizations in the process of establishing area-based management measures and environmental impact assessment of cumulative fishing activities. In line with this, regional fisheries organizations may evolve in the future to proactively adopt legal framework changes and environmental protection measures that emerge from the implementation of the BBNJ Agreement. [ABSTRACT FROM AUTHOR]

The European sardine (Sardina pilchardus) is under intense fishing pressure and exhibits distributional/abundance shifts linked to environmental change. The current understanding of population demographics needed for sustainable management is uncertain due to concerns that previous genetic studies lacked resolution and limited sampling of sardine north of the Bay of Biscay. To address these issues, we performed mtDNA sequencing and genome wide SNP analysis of samples collected across the Bay of Biscay, Celtic Sea, English Channel and North Sea. The complete SNP data reported a lack of structure throughout the sampled area compatible with high gene flow. A consensus suite of positive outlier SNPs was identified which reported a significant correlation with geographical distance with the largest differentiation between the southern Bay of Biscay and North Sea samples which also reported a significant mtDNA ΦST. While the roles of dispersal limitation and environmental heterogeneity underpinning this require further study, this adds to growing evidence that selection is influencing sardine population structure against a background of high gene flow. The results indicate that while there may be a level of demographic independence between North Sea and South Biscay sardine, the current delimitation of central (Biscay) and northern (Channel and Celtic Sea) operational stocks may misrepresent connectivity between the Biscay and Channel. The North Sea sample exhibited markedly lower mtDNA and nuclear variation than other samples. As sardine have only recently invaded the North Sea such reduced genetic variation is compatible with predictions for peripheral leading‐edge populations but contrasts with patterns for other small pelagic species and emphasises the need to consider species‐specific genetic structure in ecosystem‐based management. Nascent management of the North Sea sardine fishery must ensure that current low levels of genetic diversity are not eroded further as this may decrease the species adaptive potential and inhibit its expansion. [ABSTRACT FROM AUTHOR]

Under the Programme of integrated teacher education not a single study is recommended, the study of fish and fisheries is recommended with the study of fresh water pollution. This type study may be integrated with the study of Earth and Earth's layers of Atmosphere, Hydrosphere and Lithosphere. Pollutants are spreaded by any source in the air, soil and water. The Pollution may represent as Air pollution, water pollution and soil pollutions. The pollution is named as per their availability:- Air pollution water Pollution and Land Pollution, Land and Air Pollutants may be dissolved in water, to produce more harmful effects on the life of fishes. [ABSTRACT FROM AUTHOR]

The global biodiversity that underpins wild food systems--including fisheries--is rapidly declining. Yet, we often have only a limited understanding of how households use and benefit from biodiversity in the ecosystems surrounding them. Explicating these relationships is critical to forestall and mitigate the effects of biodiversity declines on food and nutrition security. Here, we quantify how biodiversity filters from ecosystems to household harvest, consumption, and sale, and how ecological traits and household characteristics shape these relationships. We used a unique, integrated ecological (40 sites, quarterly data collection) and household survey (n = 414, every 2 mo data collection) dataset collected over 3 y in rice field fisheries surrounding Cambodia's Tonlé Sap, one of Earth's most productive and diverse freshwater systems. While ecosystem biodiversity was positively associated with household catch, consumption, and sold biodiversity, households consumed an average of 43% of the species present in the ecosystem and sold only 9%. Larger, less nutritious, and more common species were disproportionally rep-resented in portfolios of commercially traded species, while consumed species mirrored catches. The relationship between ecosystem and consumed biodiversity was remarkably consistent across variation in household fishing effort, demographics, and distance to nearest markets. Poorer households also consumed more species, underscoring how wild food systems may most benefit the vulnerable. Our findings amplify concerns about the impacts of biodiversity loss on our global food systems and highlight that utilization of biodiversity for consumption may far exceed what is commercially traded. [ABSTRACT FROM AUTHOR]

Despite the government's active promotion of rice production, a significant portion of the population still faces food insecurity. While existing literature often highlights the success of achieving rice surplus, few studies delve into the connections between rice surplus and food security, and critically analyze why food security is persistent. In addressing this issue, the study investigates the underlying causes of food insecurity amidst the government's efforts to increase rice production. The study entails a comprehensive review of existing literature and an examination of food security in three provinces in the Cambodian Mekong Delta. It concludes that while rice intensification has led to increased rice production available for consumption, challenges persist in terms of access to and utilization of rice for food consumption. These challenges are attributed to increased production costs with minimal profit margins, indebtedness, migration, land grabs, water conflicts, and lack of institutional integration in food systems, compounded by the effects of climate change and environmental degradation. As a result, a farming household with one hectare of farmland cannot produce enough rice for food consumption. Consequently, young people opt to sell off their land to settle debts and seek employment opportunities in urban and overseas areas. [ABSTRACT FROM AUTHOR]

Southern flounder are an iconic coastal finfish through the Southeast U.S. Atlantic and Gulf of Mexico. Southern flounder spend the early part of their lives in coastal and estuarine habitats, later moving offshore to spawn. Several decades of research have provided much clarity to the biology, life history, and aquaculture aspects of southern flounder—this information is summarized and reviewed in this study. Despite substantial improvement in understanding the species, major questions remain about their recruitment, offshore behaviors, captive rearing, and management. Recently, southern flounder have also been in focus because of substantial synchronous population declines throughout their range with specific concerns that recruitment failure and possibly climate change may be implicated. Management of southern flounder has thus far taken place within individual states, but coming into focus is the possibility that larger coastwide management approaches may need to be considered due to both the migratory nature of the species and the possibility of population stressors acting at regional scales. Many states have already begun aquaculture and enhancement efforts, with an eye toward supplementing wild populations. Large group efforts, like the symposium that led to this study, will likely be needed to tackle the complex challenges confronting southern flounder. [ABSTRACT FROM AUTHOR]

The large yellow croaker, an endemic migratory species in China’s coastal waters, holds considerable economic importance. It is very necessary and significant to study the spatio-temporal evolution of large yellow croaker fishery based on environmental factors. In this paper, the HY-1C/D Coastal Zone Imager was applied to reveal distributional details of suspended sediment concentration and chlorophyll-a concentration in large yellow croaker fishery. Furthermore, combined with multi-source data, the characteristics of other environmental parameters such as temperature, salinity, current, wind and fronts were analyzed to reveal the changing of large yellow croaker fishery location. The results show that: (1) The environmental factors of large yellow croaker fishery exhibit pronounced spatial and temporal characteristics. Generally, the temperature (9-28°C), salinity (20-34 ‰) and other water environmental factors of the fishing ground are conducive to the survival and growth of large yellow croaker. The formation and change of fishery are closely related to environmental factors in the water. (2) The change of environmental factors in the water may induce the change of large yellow croaker fishery location. Winter sea surface temperature has significantly risen over the past two decades (2004-2023). With the sea surface temperature rising by approximately 2°C west of 125°E, the overwintering ground has expanded westward, increasing by nearly 29%. In addition, the scale and number of offshore windmills increased by 836% and 456% respectively over the decade (2013-2023). In 2023, offshore wind farms cover an area of 145.47 km2 and have 200 windmills. Wind turbine piles resembling artificial reefs. It can not only promote the waters vertical exchange to enhance the nutrients in upper waters but also provide a protective base for fish spawning. Thus, effectively attracting fish species. The construction of offshore wind farms has extended spawning ground north-westward to the mouth of the Yangtze River Estuary, expanding by nearly 21%. This study improved the cognition level of resources, habitat environment and change trend of large yellow croaker. It also provided technical support for the construction and protection of the large yellow croaker fishery.

The withdrawal of the United Kingdom from the European Union will likely result in reduced fishing grounds for the Belgian fishing fleet. This fleet now targets demersal fish, but there used to be a tradition of catching Atlantic herring (Clupea harengus). After the stock collapse of Atlantic herring in the 1970s, fishing on herring by the Belgian fleet did not recover and herring quotas are now exchanged with the Netherlands and Germany. To assess the feasibility of reintroducing herring fisheries for the Belgian fishing fleet, our study created spatiotemporal species distribution models for Atlantic herring in the Northeast Atlantic Ocean, focusing results on the Belgian Part of the North Sea. In total 30078 occurrence records were derived and processed to fit species-environmental relationships with temperature, salinity, seabed characteristics and plankton concentration using Maximum entropy (Maxent) models. The Area Under the Curve of the Receiver Operating Characteristic plot (AUC) and the True Skill Statistic (TSS) were used to assess model fit. Models performed well (AUC > 0.7 and TSS > 0.6). While a broad spatiotemporal distribution of Atlantic herring in the Northeast Atlantic Ocean was inferred, regional differences show that herring habitat is most suitable during winter months in the Belgian Part of the North Sea for both adult and larval herring (habitat suitability index > 75%). This regional trend in the Belgian Part of the North Sea was negatively correlated (R = -0.8) with the North Atlantic Oscillation (NAO). We anticipate that these findings will provide valuable insights for policymakers to implement sustainable fisheries management practices.

Abstract Natural resources such as fish are vital for improving human livelihood and serving as sources of food, income and employment opportunities in Ethiopia. But, its degradation and overexploitation lead to anxiety about the living standards of human beings and other living things. The degradation of these resources, which is caused by the less common participation of all stakeholders in protecting the resources, is the most challenging issue in the country. The objective of this paper is to review fishery production and management and their challenges, the extent of the overexploitation of natural resources, the contributions of collective action in fishery production and management, and fishery collective action challenges in Ethiopia. The review paper identified that the existence of a lack of strong coordination among different actors like local communities, the government, development agents, research centers and donor organizations whose concern are with the fishery sector caused the degradation of water bodies and fishery resources in Ethiopia. These issues resulted in challenges in fishery resource production and management, mismanagement in solving social differences among local communities, and low cooperation among communities in protecting fish resources. Besides, these challenges also caused a limited expansion of fishery collective action, overexploitation of fishery resources, and less concern for the protection of fish diversity species in the country. Therefore, essential policy implications forwarded are creating and improving joint collaboration between fish users, local communities, government institutions and development agents; organizing and empowering the local communities in collective action to involve them in the fishery sector to contribute to practical improvements in the protection, production, management and sustainability of fish resources.

Catch and distribution of pink salmon in the Primorye fishing subzone are compared for 2000–2023. Dynamics of the spawning run of pink salmon in 2023 is considered in detail. Commercial landing for weak odd-year broodline of this species in Primorye has increased to 1.5.103 t for the first time in the 21 century, whereas has de- creased in Khabarovsk Region. Such redistribution of pink salmon in 2023 occurred on the background of anomalous environmental conditions in the northern Japan Sea and Tatar Strait. Long-term patterns in variability of hydrometeorological parameters are analyzed and a forecast of their influence on anadromous migration of pink salmon in the Japan Sea is developed for 2024−2025.

Data of the trawl surveys for counting of pink salmon in 2022 and 2023 and results of pink salmon fishery in the main areas of the Russian Far East in 2023 are presented and the studies for understanding the state of the main pink salmon stocks and regional complexes are overviewed. The total catch in the Far-Eastern fishing basin was 478.5.103 t in 2023, including 182.4.103 t in the Bering Sea (total run — 247.1.106 ind.) and 280.8.103 t in the Okhotsk Sea (total run — 292.4.106 ind.). These values slightly exceed the forecasts of pink salmon run and catch in the Bering and Okhotsk Seas (estimated catch rates 140–150.103 t and 240–255.103 t, runs 210.106 ind. and 260–270.106 ind., respectively). For the forecast for the Okhotsk Sea, materials on differentiation of mixed pink salmon assemblages were analyzed by specialists of the Kamchatka branch of VNIRO, using both traditional methods (as morphological express- method and genetic method based on mt-DNA analysis) and a new method based on SNP-locus variability.

Results of salmon fishery in Kamchatka Region in 2023 are overviewed. Data of fishery statistics on catches of pacific salmon are presented, by fishing districts. Feasibility of fishery forecasts is estimated. Seasonal dynamics of landing is shown for the main stocks of five salmon species. The spawning stocks on the eastern and western coasts of Kamchatka are assessed.

Seasonal dynamics for expected and actual catches of pink salmon on the northeastern and southeastern coasts of Sakhalin and on Iturup Island are compared for 2018–2023. The actual values differed from the expected ones on average by a factor of two. Large errors in the forecast were caused by both objective reasons (unaccounted random natural cases) and subjective reasons (inaccuracy of the primary data used in calculations).

Seasonal and bathymetric distribution of the main age groups of pacific cod in the northern Japan Sea are considered on the data of bottom trawl surveys in 1980–2023. The main wintering and spawning accumulations, where the fish concentrate from December to January and then spawn in February-March, are formed on the external shelf and the upper continental slope along the western coast approximately between Peter the Great Bay and 47о N and along the eastern coast between Cape Krillon and 47о 30′N. The juveniles have feeding migrations from April to May, while older age groups complete the migrations a month later. They migrate in three main directions: from the areas at the mainland coast – southwestward and northeastward and from the areas at western Sakhalin — southward. The juveniles feed on shallows in Peter the Great Bay, northern Tatar Strait, and on southwestern shelf of Sakhalin between the Nevelsky Bay and Cape Krillon, whereas the feeding grounds for older groups occupy two vast areas including Peter the Great Bay with the adjacent southeastern shelf of Primorye and the shelf of northern Primorye in the Tatar Strait (to the north from 47о N) with the whole shelf of Sakhalin. In the northern Tatar Strait (northward from 48о N), the cod belonged to the Primorye and Sakhalin stocks can feed together. The feeding season lasts from June to September. The older cod feed usually deeper that the juveniles. Back migrations of cod for wintering occur from October to November. Because of a joint feeding area where the mainland and Sakhalin stocks are able to mix, the bottom trawl surveys at Primorye coast cannot be used for correct assessment of the total available catch (TAC) in this fishing district. To improve quality of the cod fishery forecasts, the methods of cohort or production analyses should be used, with the control by bottom trawl surveys data, as alternative information about the state of cod stocks, taking into account the abovementioned patterns of seasonal distribution and migrations.

The escapement objective used to manage fisheries for Sacramento River Fall Chinook (SRFC) Salmon was established in 1984. Despite substantial changes to the system and multiple calls to re-evaluate the objective, data and analytical limitations have slowed progress. Synthesizing the available information is further complicated by the different measurement scales employed by relevant studies. Here, I offer a modeling framework for integrating consideration of established hatchery spawning goals, natural-area production or habitat capacities measured at varying spatial scales, and policy decisions about what fraction of potential natural production is desired along with risk tolerance. The model allows evaluating how likely a potential escapement goal (measured at the currently-used scale of fall-run adults returning to both hatcheries and natural areas throughout the Sacramento River basin) is both to meet hatchery goals and to produce at least a specified fraction of potential natural production. The framework also incorporates consideration of forecasting and ocean harvest planning error into identifying a pre-season planning target and its probability of resulting in escapement at least as high as the goal. The model indicates that the low end of the current escapement goal range of 122,000 to 180,000 adults, if achieved, would be more likely than not to achieve hatchery goals while achieving around 50% of potential natural production. Realized escapement equal to the high end is modeled to be very likely to achieve hatchery goals, and likely to achieve around 75% of potential basin-wide natural production or around 60% of upper Sacramento River potential production. The model indicates diminishing returns from total adult SRFC escapements higher than about 300,000 adults. However, past performance of forecast and harvest-planning models suggest that a pre-season target higher than the ultimate escapement goal is needed to have even a 50% chance of achieving the escapement goal.

Marine protected areas (MPAs) can protect and restore marine biodiversity and fisheries, but there are concerns that they may also benefit invasive species. The spatial and temporal colonization of invasive lionfish (Pterois miles) in the eastern Mediterranean was compared across zones with varying fishing restrictions (no fishing, recreational and commercial fishing, and commercial fishing only), and stations where targeted removal events were conducted by volunteer SCUBA divers. Lionfish density in no fishing areas was nearly double that of areas with commercial fishing only, and over four times greater than in areas where both commercial and recreational fishing were allowed. Lionfish density increased with depth, possibly due to easier human exploitation in shallow waters (0–10 m) that are accessible to recreational spearfishers. Targeted removals by volunteer divers decreased lionfish densities by over 60%, while areas without removals had a 200%–400% increase. Along with management actions, natural and ecological processes might drive lionfish densities within MPAs, and the speed with which lionfish colonized fishery‐restricted zones, emphasized the need for a more sophisticated MPA management strategy that considers invasive species impacts and dynamics in an ecosystem‐based approach. [ABSTRACT FROM AUTHOR]

The document titled "Fishery as Socio-Cultural Symbol: Conceptualising Marine Pollution and the Dynamics of Displacement in Selected Nigerian Novels" explores the use of fishery as a symbol in Nigerian literature to represent socio-cultural issues such as marine pollution and displacement. The authors discuss the significance of tides and fishery in providing insights into these topics and highlight the portrayal of environmental degradation and dispossession in Nigerian novels. The article draws on various sources, including the African Association of Political Science, IDMC Report, and Journal of Sustainable Development in Africa, to support its analysis. [Extracted from the article]

This paper proposes a fishery model with price fluctuations and predators. Under the assumption that the price changes much faster than other variables in the system, the fishery model can be considered as a fast–slow system. Using the approximate aggregation method, a simplified three-dimensional model is used for further research. The results indicate that due to overfishing by fishermen and the presence of predators, fish populations may become extinct, which is also known as catastrophic equilibrium. To avoid this situation, we propose two solutions. The first is to establish marine protected areas (MPAs) that prohibit fishing. We propose a fish population dynamics model with MPA, assuming that fish and predators move freely in protected areas and fishing areas. The results show that it is necessary to establish MPA. The second type is that regulatory agencies can control overfishing by fishermen by increasing taxes, thereby avoiding a catastrophic equilibrium. The ultimate goal is to achieve maximum economic benefits while maintaining balanced development of the ecosystem. [ABSTRACT FROM AUTHOR]

Octopus fisheries face heightened demand driven by depleted fish stocks and escalating economic value, leading to overextraction of octopus populations and magnifying threats to coastal ecosystems and the livelihoods of fishers who depend on them. Implementation of management strategies such as periodic fishing closures can offer sanctuary for octopus, providing the necessary space and time for the growth and reproduction of this rapidly proliferating species. Despite evidence of positive management outcomes, the role of periodic closures in the long-term sustainability of octopus populations remains uncertain. Here, we examine trends in octopus landings over time and the effects of periodic closures along the Mozambique Channel from Comoros to Madagascar (12°-25°S). Long-term trends in octopus landings varied across three regions: generally stable over a 6-year period in Comoros, increasing over a 4-year period in the Barren Isles and declining over a 17-year period in Atsimo Andrefana, Madagascar. We observed a significant increase in mean catch per unit effort (CPUE, kilograms/fisher-day), and mean total catch (kilograms/day) following periodic closures across villages extracting octopus from closure areas. When evaluating each region independently, we observed this positive effect across Comoros and Atsimo Andrefana, Madagascar while trends in the Barren Isles showed no effect of octopus closures. We applied generalized linear mixed models to examine the influence of 10 covariates on mean daily total catch and CPUE within 7 days and 30 days post-closure. Baseline conditions (quantified by the pre-closure CPUE and daily total catch), closure duration and start month of closure had positive, statistically significant correlations with post-closure CPUE and daily total catch. Additionally, closure duration from 13 to 16 weeks and closure size of approximately 70 hectares were qualitatively associated with net gains in CPUE. Although periodic closures yield positive outcomes for octopus fisheries, the effects may be short-lived, as observed in Atsimo Andrefana, Madagascar, where catch declined over the long-term despite temporary improvements. Our findings underscore a need for a diverse portfolio of management strategies to restore and sustain populations over the long-term. [ABSTRACT FROM AUTHOR]

Octopus cyanea (Gray, 1849), abundant in the South‐West Indian Ocean (SWIO), constitutes a vital resource for both subsistence and commercial fisheries. However, despite this socioeconomic importance, and recent indications of overfishing, little is known about the population structure of O. cyanea in the region. To inform sustainable management strategies, this study assessed the spatio‐temporal population structure and genetic variability of O. cyanea at 20 sites in the SWIO (Kenya, Tanzania, Mozambique, Madagascar, Mauritius, Rodrigues, and the Seychelle Islands) by complementary analysis of mitochondrial DNA (mtDNA) noncoding region (NCR) sequences and microsatellite markers. MtDNA analysis revealed a shallow phylogeny across the region, with demographic tests suggesting historic population fluctuations that could be linked to glacial cycles. Contrary to expectations, NCR variation was comparable to other mtDNA regions, indicating that the NCR is not a hypervariable region. Both nuclear and mtDNA marker types revealed a lack of genetic structure compatible with high gene flow throughout the region. As adults are sedentary, this gene flow likely reflects connectivity by paralarval dispersal. All samples reported heterozygote deficits, which, given the overall absence of structure, likely reflect ephemeral larval recruitment variability. Levels of mtDNA and nuclear variability were similar at all locations and congruent with those previously reported for harvested Octopodidae, implying resilience to genetic erosion by drift, providing current stock sizes are maintained. However, as O. cyanea stocks in the SWIO represent a single, highly connected population, fisheries may benefit from additional management measures, such as rotational closures aligned with paralarval ecology and spanning geopolitical boundaries. [ABSTRACT FROM AUTHOR]

In just a few years motorcycles had become an irreplaceable object for the daily life of Indigenous people in the Gran Chaco region. In spite of their pervasiveness, there are still many aspects to this current dissemination that remain to be unraveled. This paper explores the ways in which motorcycles have been incorporated into Indigenous material culture and the ways they are reshaping Indigenous perceptions and relations with the local environment. Starting from the machines and their uses is a way to not confine Indigenous people to a position as victims of modernity, but rather to recognize their proactive role in the ongoing reproduction and transformation of their cultural world. For this purpose, I take the example of the Wichí fishery to see how this cultural practice is changing as fishermen adopt motorcycles as means of transport. I investigate this practice and its transformations based on ethnographic fieldworks carried out with several communities settled on the banks of the Pilcomayo River, as well as readings of the ethnological literature which contains detailed descriptions of this practice. By tracing its past and ongoing transformations, I show how the hold and spatial organization of Wichí fishery has evolved as motorcycles spread to the whole Pilcomayo area. Their adoption redefines fishermen perceptions and relations with the surrounding environment, which is now understood from a new mechanized and motorized perspective of capitalization and exploitation. Indeed, while motorcycles allow them to integrate into the market, they further promote market penetration on Indigenous lands. At the same time, I demonstrate how motorcycles allow fishermen to overcome the inconveniences of an intractable river and new infrastructures that hinder fishing practices, as well as to bypass the attempts to privatize the riverbanks. In a way, the fishermen are more resilient to these sudden changes thanks to motorcycles. [ABSTRACT FROM AUTHOR]

Conservation of flagship and umbrella species has popular support and benefits coexistent species. We investigated whether the Caribbean sharpnose shark Rhizoprionodon porosus gathers necessary attributes of a 'flagship umbrella' species in the region of the Artificial Reef Complex of Guaxindiba (ARCG), southeastern Brazil. To do so, we compared fish community in areas and periods with and without this species, including areas with artificial reefs (ARs) and control areas (CAs); we combined these data with interviews with fishers. Ichthyofauna richness and abundance were higher in co-occurrence with the Caribbean sharpnose shark mainly in ARs. Thus, from an ecological standpoint, this shark can be considered an umbrella species. Moreover, this species raised awareness among fishers for conservation, mainly because of its commercial value and risk of losing their income, characterizing it as a flagship species. Therefore, it is recommended that sharks become symbols in conservation actions aiming the sustainability of the ARCG. [ABSTRACT FROM AUTHOR]

The aggregation location of fish is more difficult to predict, due to the uncertain upstream path in the river. The proficient guidance of fish upstream behavior is essential to enhance the efficiency of fish passage facility inlets. In this research, a fish guide weir was introduced and assessed using three-dimensional numerical simulations of the flow field and the Active Fish Migration (AFM) model. An empirical test was carried out with the live fish within the context of the fish passage facilities in the Yaojiaping Water Conservancy Hub Project at the Hydropower Station. The results showed that the water surface differential between upstream and downstream of the fish guide weir ranged from 0.36 to 0.40 m. The flow velocity over the weir reached 1.5 to 2.8 m/s, indicating the barrier for fish migration. The singular low-flow velocity upstream channel was formed on the downstream side of the guide weir, thus directing fish towards the inlet of the fish collecting channel. The fish guide weir was then validated to select the exclusive route of the fish collecting channel. A fish migration model was used to predict the fish guide performance of the fish guide weir. The results demonstrated that there were over 90% of the fish trajectories in consistent patterns under both high and low downstream water level conditions. Specifically, the fish also migrated upstream along the right bank of the river and the low-flow channel on the downstream side of the fish guide weir. Ultimately, they congregated at the fish inlet of the fish collecting channel. In the fish release test, all tested individuals entered the fish collecting channel, further confirming that the fish guide weir effectively guided the fish swimming paths. A singular aggregation area was established at the fish inlet of the fish collecting channel. The fish guide weir can enrich the form of ecological hydraulic buildings. The finding can also provide a strong reference for the innovative hydraulic design at the inlet of the over-fish facility, particularly for the local improvement of the downstream river. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian Ocean University is the property of Journal of Dalian Ocean University Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract The European sardine (Sardina pilchardus) is under intense fishing pressure and exhibits distributional/abundance shifts linked to environmental change. The current understanding of population demographics needed for sustainable management is uncertain due to concerns that previous genetic studies lacked resolution and limited sampling of sardine north of the Bay of Biscay. To address these issues, we performed mtDNA sequencing and genome wide SNP analysis of samples collected across the Bay of Biscay, Celtic Sea, English Channel and North Sea. The complete SNP data reported a lack of structure throughout the sampled area compatible with high gene flow. A consensus suite of positive outlier SNPs was identified which reported a significant correlation with geographical distance with the largest differentiation between the southern Bay of Biscay and North Sea samples which also reported a significant mtDNA ΦST. While the roles of dispersal limitation and environmental heterogeneity underpinning this require further study, this adds to growing evidence that selection is influencing sardine population structure against a background of high gene flow. The results indicate that while there may be a level of demographic independence between North Sea and South Biscay sardine, the current delimitation of central (Biscay) and northern (Channel and Celtic Sea) operational stocks may misrepresent connectivity between the Biscay and Channel. The North Sea sample exhibited markedly lower mtDNA and nuclear variation than other samples. As sardine have only recently invaded the North Sea such reduced genetic variation is compatible with predictions for peripheral leading‐edge populations but contrasts with patterns for other small pelagic species and emphasises the need to consider species‐specific genetic structure in ecosystem‐based management. Nascent management of the North Sea sardine fishery must ensure that current low levels of genetic diversity are not eroded further as this may decrease the species adaptive potential and inhibit its expansion.

Abstract Seal scarers (or acoustic harassment devices, AHDs) are designed to deter seals from fishing gear and aquaculture operations, as well as to prevent seals from entering rivers to avoid predation on valuable fish. Our study investigated the potential effects of AHDs on non-target species, specifically the Eurasian otters (Lutra lutra), by testing the reaction of two rehabilitated otters to simulated AHDs sounds at 1 and 14 kHz, with a received sound intensity of 105–145 dB re 1 µPa rms. The 1 kHz sounds were used to investigate alternative frequencies for scaring seals without scaring otters. The otters reacted to both 1 and 14 kHz tonal signals when retrieving fish from a feeding station 0.8 m below the surface. Their diving behaviour and time to extract food progressively increased as sound intensity increased for all tested sound levels. Notably, the sound levels used in our tests were significantly lower (40–80 dB) than the source levels from commercial AHDs. These findings highlight the importance of caution when using AHDs in river and sea habitats inhabited by otters, as AHDs can change their behaviour and potentially result in habitat exclusion.

Grimothea monodon, an important fishery resource in the Humboldt Current marine ecosystem (HCE), present two contrasting morphotypes (PM, pelagic morphotype; BM, benthic morphotype). The fishery management of G. monodon is focused on understanding only fishery aspects that apply to a limited area, and there are currently no studies that evaluate the nutritional status of these morphotypes. This study evaluated the biological performance of PM and BM, analyzing the body (size, CL; weight, W; condition factor, Kn) and biochemical condition (glucose, G; proteins, P; lipids, L; fatty acids, FAs). The results reveal that G. monodon showed differences in CL and W between morphotypes, with higher values in BM than PM. The Kn was different between morphotypes with a tendency of isometric growth. In turn, the G contents were higher in PM than BM, while the contents of P, L, and FAs showed an opposite tendency, with higher contents recorded in BM than PM. Our findings suggest that the Kn should be included to strengthen the biological parameters and their relationships used in fishery management models. Differences in the biochemical condition between morphotypes can be considered potentially adaptive, in response to the combined effect of environmental factors that vary in the HCE.