Coastal Fisheries Research Articles

Composition and structure of the mangrove fish and crustacean communities of Vanga Bay, Kenya

Mangroves support coastal fisheries, particularly by providing nurseries for juvenile fish. However, much remains unknown about the fish and crustacean communities in mangroves and about the lifecycles and behaviours of individual species. This study is the first to describe the fish and crustacean communities in the Vanga mangrove ecosystem, the largest mangrove forest and the most important marine fisheries landing site in southern Kenya. Using fyke nets, 14 mangrove creek sites were sampled once every 3 months during spring tides, between September 2015 and September 2017. The sampling period covered the north east (NEM) and south east (SEM) monsoon seasons. A total of 1,879 fishes and 1,132 crustaceans were caught, represented by 59 and 16 species, respectively. Over 95 % of the fishes caught were juveniles with 50 % of both fish and crustacean species being of commercial importance. About 70 % of the catch was dominated by only 6 fish species with Yarica hyalosoma and Acropoma japonicum contributing 44 % of the total abundance. Penaeus semisulcatus and Penaeus indicus dominated the crustaceans. Fish abundances differed significantly between seasons, with the SEM catches almost three times higher than those in the NEM, while crustaceans displayed no clear seasonality. The study documents for the first time the fish and crustacean communities in Vanga mangroves and confirms their importance as juvenile habitat for commercial species. The importance of mangrove and near mangrove habitat as nursery habitat for both fish and crustaceans emphasizes the need for conservation particularly of seaward edges

Is Diversity the Missing Link in Coastal Fisheries Management?

Fisheries management has historically focused on the population elasticity of target fish based primarily on demographic modeling, with the key assumptions of stability in environmental conditions and static trophic relationships. The predictive capacity of this fisheries framework is poor, especially in closed systems where the benthic diversity and boundary effects are important and the stock levels are low. Here, we present a probabilistic model that couples key fish populations with a complex suite of trophic, environmental, and geomorphological factors. Using 41 years of observations we model the changes in eastern Baltic cod (Gadus morhua), herring (Clupea harengus), and Baltic sprat (Sprattus sprattus balticus) for the Baltic Sea within a Bayesian network. The model predictions are spatially explicit and show the changes of the central Baltic Sea from cod- to sprat-dominated ecology over the 41 years. This also highlights how the years 2004 to 2014 deviate in terms of the typical cod–environment relationship, with environmental factors such as salinity being less influential on cod population abundance than in previous periods. The role of macrozoobenthos abundance, biotopic rugosity, and flatfish biomass showed an increased influence in predicting cod biomass in the last decade of the study. Fisheries management that is able to accommodate shifting ecological and environmental conditions relevant to biotopic information will be more effective and realistic. Non-stationary modelling for all of the homogeneous biotope regions, while acknowledging that each has a specific ecology relevant to understanding the fish population dynamics, is essential for fisheries science and sustainable management of fish stocks.

Salt marsh restoration: an overview of techniques and success indicators.

Coastal wetlands including salt marshes are among the most productive ecosystems on Earth. They are known for improving the quality of coastal water and provisioning coastal fisheries. However, this ecosystem is under potential threat due to urban coastal land reclamation, limited sediment supply, increased nutrient/eutrophication, and sea level rise. Therefore, restoration efforts to protect the degraded salt marsh habitat are considerably increasing worldwide. In this paper, we present an overview of salt marsh restoration techniques and success indicators. Published scientific literature in English language was collected by searching the most relevant keywords from popular search engines, namely, Google Scholar, Scopus, and Mendeley to get the information about salt marsh restoration techniques and success indicators. This study comprehensively reviewed data from 78 peer-reviewed papers. Results indicated that much of the salt marsh was restored through assisted abiotic strategies (e.g., recovery of tidal exchange, managed realignment, and sediment level amendment). A total of 214 indicators were found, spanning over six major ecological attributes such as structural diversity, ecosystem functions, physical conditions, species composition, external exchange, and absence of threat. Author keywords analysis revealed several hotspots for recent research (e.g., 16s rRNA, fungi, microbial communities, carbon accumulation, and blue carbon). This paper proposes a model for restoring degraded salt marsh, as well as tracking their success.The information presented here will assist the marine ecosystem restoration practitioners in getting a comprehensive understanding of salt marsh restoration success evaluation.

种间互作对雷州湾海域鱼类群落结构的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 种间互作对雷州湾海域鱼类群落结构的影响 DOI: 10.5846/stxb202108212330 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划"蓝色粮仓科技创新"重点专项资助（2020YFD0901103）；南方海洋科学与工程广东省实验室（湛江）资助项目（ZJW-2019-06） Importance of species interactions in structuring fish community of Leizhou Bay waters, northern South China Sea Author: Affiliation: Fund Project: The National Basic Research Program of China (973 Program),其他 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:从鱼类种间互作及其生态网络特征视角研究鱼类群落结构特征，对解析多鱼种共存机制和基于群落水平的多鱼种资源管理均具有重要意义。为分析鱼类资源利用的竞争互作对群落结构稳定性的影响，根据2016-2018年8个航次的雷州湾海域底拖网调查的鱼类数据，将空间生态位重叠理论和生态网络建模相结合，从种间互作的角度应用加权聚类系数C、加权平均路径长度A、关联度Co等指标分析鱼类的群落结构。结果表明：①鱼类生态位重叠所形成的种间互作网络季节变动较大，而年度变动则相对较小，共包含鱼类58-122种，种间互作的关系数量1318-7103。②雷州湾海域鱼类群落内种间互作密集，聚合程度高（C介于0.84-0.98）且能量传递效率高（A介于0.02-0.09），呈现互作弱化之趋势（Co介于0.32-0.48），群落结构总体较稳定。③小尺度范围（20°40'-21°00'N，110°30'-110°45'E）内，鱼类群落内种间互作特征是维持多种鱼类共存的重要内因。该特征表现为季节和年度的变化总体上相似，种间直接关联程度与种间互作强度呈正相关（P<0.01），而局部聚合程度与种间直接关联、互作强度均呈负相关（P<0.01）。本研究可为鱼类群落结构稳定性的量化评价和资源养护的管理规划提供参考依据。 Abstract:The interactions between fish species and their roles in the ecological network on structuring the fish community is a matter of great concern not only for understanding the species coexistence, but also for the multispecies fishery management and conservation at the community level. The data from the bottom trawl surveys of eight cruises in Leizhou Bay waters northern South China Sea during 2016 and 2018 were applied to analyze how the species interactions (interspecific competition in limited resources and space) affected the stability of fish community structure in seasons and years. Combining theories on spatial niche overlap and the ecological network modeling, six indicators such as the weighted clustering coefficient (C), weighted average path length (A), connectance (Co), degree (K), weighted node strength (Si), and locally weighted clustering coefficient (Ci) were respectively applied to measure the degree of community aggregation, the overall energy transfer efficiencies between species, interspecific connectivity, the degree of directly interspecific associations, the intensity of species interactions, and the degree of local aggregation between species. And then we analyzed the importance of species interactions in structuring fish community of Leizhou Bay waters. The results showed that:①the network of species interaction which formed by spatial niche overlap of fishes varied more widely in seasons, but comparatively minor between years, including 58-122 kinds of fishes, and 1318-7103 lines (links between species interactions). ②The fish community was characterized with the intensive interactions, high degrees of aggregation (C ranged between 0.84 and 0.98), high energy transfer efficiencies (A ranged between 0.02 and 0.09), with a weakening tendency of species interactions (Co ranged between 0.32 and 0.48) from 2016 to 2018. The fish community of Leizhou Bay waters was kept in a state of stability in all. ③At the local small scale (20°40'-21°00'N, 110°30'-110°45'E), traits of species interactions of the fish community were similar on the seasonal and annual scale. Two traits were the important internal factors driving the coexistence of multiple fish species in the Leizhou Bay waters. The first was the degree of directly interspecific associations which was positively correlated with the intensity of species interactions (P<0.01). And the second was the degree of local aggregation which was negatively correlated with both the degree of directly interspecific associations and the intensity of species interactions (P<0.01). This study provides clues for the quantitative analysis on the stability of fish community structure and planning of effective coastal fishery resources management and conservation. 参考文献 相似文献 引证文献

Three-dimensional Sustainability Profile of the coastal fishery of Jalisco State, Mexico

Sustainability is a basic tool in decision-making regarding human resources distribution for government programs applied to communities. The sustainability index reflects the level of impact on the effectiveness of its application. It is important to mention that a study of this nature has not been reported in the scientific literature for Mexican fishery activity on Jalisco Coast, Mexico. Thus, the results of this research will support the fishermen's federations in decision-making about their productive work. The main objective was to determine the sustainability index for Cihuatlán, La Huerta, Tomatlán, and Puerto Vallarta municipalities of Jalisco state, Mexico by applying the IRS methodology. Even when the productive activity is economically profitable, its do not contribute positively to the Social and Environmental sustainability indices. The index of the three-dimensional sustainability of the Jalisco Coast, Mexico fishing activity is 2,33, which is considered very low about what is desirable, which should be greater than 4. In other words, there is no positive development in the quality of life of fishermen and environment care for the catch areas and species of interest for commercial fishing activities.

Local Ecological Knowledge in Community-Based Management as Smart Management Options for Coastal Fisheries: A Review of the Sri Lanka Context

Even though small-scale fisheries throughout the globe are based on local ecological knowledge (LEK), it is often not involved in the decision-making process. An attempt is made to review the potential of using LEK of traditional coastal fisher communities in Sri Lanka and self-governing institutions in managing fisheries commons sustainably. Fisheries management in Sri Lanka is mainly a top-down system through the state legislation, while many fishing communities still maintain some level of informal or traditional management systems. The traditional community-based fisheries management (CBFM) systems in coastal fisheries of Sri Lanka, which are essentially based on LEK of fisher communities, hold long history from several decades to centuries. In active fisheries, i.e ., beach seining and stilt fishing, traditional fishers accurately use LEK for day-to-day fishing activities for predicting harvests before operating the fishing gear. Long-term viability of beach seining, stilt fishing, brush park fishing, kraal fishing and stake net fishing systems in coastal fisheries of Sri Lanka confirms that CBFM systems in coastal fisheries provide better economic and livelihood standards for fisher communities. Empirical studies confirm that the coastal fisher communities manage fisheries commons through self-governing institutions through which the property rights are vested to fisher communities averting the common pool dilemma. This synthesis confirms that fishers’ LEK is an integral part of CBFM systems of coastal fisheries, which strengthen the collective action of the fishers, and is invaluable for sustaining the CBFM systems for the long run. It is clear that CBFM systems governed through robust customary institutions and evoked by traditional authority and LEK of fishers are vital for the sustainability of the coastal fisheries. In conclusion, CBFM systems and LEK can be hailed as smart management options, which can be an alternative to centralized fisheries management in Sri Lanka.

Emerging Information and Communication Technologies for Monitoring India's Marine Small-Scale Fisheries, Opportunities for Inclusion, Risks of Exclusion

Adaptive, inclusive and effective management of fisheries resources is dependent on knowledge from multiple quantitative and qualitative sources. As technology advances, there is an increasing interest in digital and automated solutions for gathering fisheries data. Small-scale fisheries (SSF) have presented a persistent challenge to many centralized quantitative data collection systems, and frequently maintain the status of ‘unreported’. This unreported nature often implicates SSF in the definition and discussions of illegal, unreported and unregulated (IUU) fishing. Monitoring, control and surveillance are seen as a vital part of the solution to IUU fishing, with substantial investment being put into increasingly sophisticated technology for tracking fishing vessels. For the past few years, India has been attempting to pass legislation to require all vessels, from small-scale to industrial, to install vessel monitoring systems on the grounds of national security and combating IUU fishing. However, there are concerns that a securitized and top-down approach to implement vessel tracking is not only wasteful but risks further marginalization of small-scale fishers from the resource, and fisheries groups from governance processes. India should seek to solve the underlying causes of IUU fishing while also developing collaborative monitoring and community-based management models. In this paper, we review evidence of emerging information and communication technologies and approaches in SSF and discuss how, if introduced and managed through collaborative processes, they could be used as a platform to strengthen inclusive governance, increase sustainability and improve wellbeing in coastal fisheries in India.

Mangrove crab intestine and habitat sediment microbiomes cooperatively work on carbon and nitrogen cycling.

Mangrove ecosystems, where litter and organic components are degraded and converted into detrital materials, support rich coastal fisheries resources. Sesarmid (Grapsidae) crabs, which feed on mangrove litter, play a crucial role in material flow in carbon-rich and nitrogen-limited mangrove ecosystems; however, the process of assimilation and conversion into detritus has not been well studied. In this study, we performed microbiome analyses of intestinal bacteria from three species of mangrove crab and five sediment positions in the mud lobster mounds, including the crab burrow wall, to study the interactive roles of crabs and sediment in metabolism. Metagenome analysis revealed species-dependent intestinal profiles, especially in Neosarmatium smithi, while the sediment microbiome was similar in all positions, albeit with some regional dependency. The microbiome profiles of crab intestines and sediments were significantly different in the MDS analysis based on OTU similarity; however, 579 OTUs (about 70% of reads in the crab intestinal microbiome) were identical between the intestinal and sediment bacteria. In the phenotype prediction, cellulose degradation was observed in the crab intestine. Cellulase activity was detected in both crab intestine and sediment. This could be mainly ascribed to Demequinaceae, which was predominantly found in the crab intestines and burrow walls. Nitrogen fixation was also enriched in both the crab intestines and sediments, and was supported by the nitrogenase assay. Similar to earlier reports, sulfur-related families were highly enriched in the sediment, presumably degrading organic compounds as terminal electron acceptors under anaerobic conditions. These results suggest that mangrove crabs and habitat sediment both contribute to carbon and nitrogen cycling in the mangrove ecosystem via these two key reactions.

Dwindling Coastal Fisheries Biodiversity of Bangladesh: The Causes and Effects

Being a sub-tropical nation in the Ganges-Brahmaputra-Meghna (GBM) Delta with long shoreline along the Bay of Bengal, the coast of Bangladesh is blessed with rich living resources. The country has a coastline of about 710 km and an Exclusive Economic Zone of 121,110 km2. Bangladesh’s coastline extends from St. Martin’s living coral island in the south-east to the Sundarbans-world’s largest adjoining mangrove-in the south-west. The coast holds diverse habitats- coral, sandy, muddy and rocky beaches, salt marshes, grass beds and mangroves - with uniquely diversified faunal configurations. So far, 730 fishes, 150 crustaceans and 336 mollusks have been recorded from the coastal waters of Bangladesh, apart from a number of cephalopods, sea turtles, reptiles, and mammals. Increasing population, destruction of mangroves, pollution, overfishing, and illegal/destructive fishing using set bag nets and monofilament gillnets and an extensive collection of shrimp larvae are the root causes of biodiversity loss in the coast. Already, the near-shore fish stocks are overexploited and catch per unit fishing effort is falling and many shrimp and fish stocks are in the decline. The percentage contribution of marine segment in the fisheries sector of the country is decreasing every year. About 28% of the coastal fishes assessed by IUCN (International Union of Conservation of Nature) are now placed under IUCN Red List of ‘threatened species’. To ensure sustainable fisheries management, a number of laws have been put in place, but the implementation of these laws and regulations is constrained due to conflicts and non-compliance by the stakeholders. Hence, Bangladesh needs a robust legal and policy framework for conservation and sustainable utilization of the coastal resources. Establishment of sanctuaries and marine protected areas following a co-management approach can achieve notable success in protecting coastal biodiversity. Strict enforcement of legal measures aimed at protection of mangroves, development of eco-coastal tourism and social safeguards for resource conservation and management, is needed for long-term and sustainable management of coastal biodiversity of Bangladesh.

Managing Marine Mammals and Fisheries: A Calibrated Programming Model for the Seal-Fishery Interaction in Sweden

This paper develops a model based on the concept of Positive Mathematical Programming (PMP) that is useful for ex-ante analyses of how policy measures affect commercial fisheries. PMP models are frequently used in agriculture, but rarely for analyzing fisheries. Fisheries often face a large set of constraints such as effort regulations and catch quotas of which some might be binding and others not. An econometric approach is developed for calibrating models with both binding and non-binding constraints. The interaction between seals and Swedish fisheries is used as an empirical application. Seal interaction is modeled as seals predating fish from passive gear (nets and hooks), which is primarily an issue for the coastal fishery. The model contains 24 fleet segments involved in 247 different fishing activities in 2012. The results show that if no further management action is taken, fisheries using passive gear will reduce their activities from about 46 000 days at sea per year to about 41 000 and reducing their economic performance from losses of about 2 million Euros to about 3.3 million. The impact from seals can be reduced by reducing the seal population or providing economic compensation.

Air bubbling assisted solar-driven submerged vacuum membrane distillation for aquaculture seawater desalination

Submerged vacuum membrane distillation (S-VMD) was proposed in this work to desalinate aquaculture seawater. In this S-VMD without feed-pumping system, the hydrophobic hollow fibre membranes are fully immersed in the feed tank with internal coil heated by solar evacuated tube collector. In this study, indoor test under steady-state condition was compared to the outdoor test under solar intensity variation. The system’s feasibility and practicality were investigated. In the daily outdoor performance test, the solar-powered S-VMD system obtained permeate flux at 2.1–5.2 kg/m2h, depending on the solar intensity profile. Air bubbling as enhanced flow promoter and anti-fouling technique was employed to overcome the polarizations at the membrane boundary layer. Compared to non-bubbling, the bubbling approach in the S-VMD system effectively achieved higher flux and fouling reduction with better permeate quality. It is suggested that the system can be applied in energy-deprived and space-constricted remote area, particularly marine aquaculture farm to produce clean water for coastal fishery communities.

Monitoring coastal aquaculture devices in Taiwan with the radio frequency identification combination system

ABSTRACT Marine debris significantly influences the environment and economics of marine ecosystems. Measures to ban illegally discarded materials using monitoring techniques are expected to mitigate marine debris mismanagement. For example, derelict oyster farming rafts along the southwestern coast of Taiwan have been a source of marine debris pollution since the 1980s. An efficient inspection system is an urgent requirement for monitoring oyster farming areas and, is expected to implement control and surveillance measures for litter discarded from coastal fisheries. To address this issue, this study examined combinations of radio frequency identification (RFID), drone archiving, and onshore receiving systems to ascertain the positions of oyster rafts and their owners with digitally tagged labels. The results showed that the two proposed monitoring systems are feasible for use in marine environments. The RFID signals archived by the drone reached 100% of the 200 tags with a spatial bias ranging from 2.38 to 59.99 m. RFID-GPS hybrid tag signals received by the onshore station covered 100% of the 20 tags with spatial bias ranging from 1.27 to 10.47 m. The RFID-GPS hybrid system was confirmed as a feasible approach for monitoring oyster rafts within 3 km of the coast. The real-time (1 h intervals) position and attributes of each raft detected by the system indicated that our designed techniques enhance responsible fishery surveillance and management of coastal aquaculture worldwide.

Relative importance of habitat mosaics for fish guilds in the northeastern coast of Brazil

The identification of patterns in habitat use by fish guilds may provide an integrated perspective of coastal mosaics. Thus, we used multivariate analyses to assess the relative importance of habitat types for fish guilds based on density and species composition throughout a seasonal event in the northeastern coast of Brazil. Our results showed a great variability of responses found for each functional group, with species composition of guilds that are estuarine-related being affected by habitat types (p=0.001) and seasons (p=0.008), whereas the facultative estuarine users showed no significant relationship with both variables (p=0.95). Specific habitat association patterns were not found for guilds, though solely estuarine species (p=0.041) and marine straggler fishes (p=0.027) were related to environmental conditions that varied greatly with seasonality (i.e., rainfall and salinity rates), indicating that temporal changes in the region allow species from different guilds to explore the whole coastal mosaic at different scales of space and time. For this reason, we highlight that the integrated protection of beaches, mangroves and seagrass compose an imperative strategy to sustain the complexity of inshore coastal areas that are highly productive for coastal fisheries and fundamental to maintain coastal livelihoods.

Socio-ecological change in the Ruvu Estuary in Tanzania, inferred from land-use and land-cover (LULC) analysis and estuarine fisheries

Ecosystem goods and services derived from estuaries have sustained coastal livelihoods in the Western Indian Ocean (WIO) region throughout recorded history. Estuaries provide fertile and seasonally irrigated space for planting crops, mangrove products for construction and fuel, and fish as a protein source. Human population growth and an escalating demand for natural resources threaten estuarine critical habitats and their functioning, exacerbated by the effects of climate change. Decadal and seasonal land-use and land-cover (LULC) changes in the Ruvu Estuary in Tanzania were investigated through analysis of Landsat 5/8 and Sentinel-2 satellite images. The estuary is river-dominated and truncated near the coast during high river flow, with tidal influence extending approximately 12 km upstream during low river flow. LULC change detection targeting nine classes (water, developed, barren, forest, grasslands, cultivated, mangroves, wetlands and mudflats) showed that estuary-associated wetlands and mangroves had declined significantly over the past two decades (1995-2016) making way for developed land (growth of Bagamoyo Town), cultivated land (agricultural expansion with increasing population) and grasslands (coastal habitat changes). Seasonal LULC changes were conversion of wetlands to cultivated land after the wet season, and transformation of fallow wetlands to grasslands. The estuarine fishery relied on a small number of mainly freshwater and marine migrant species, compared to a highly diverse mix of mainly marine species in the nearby coastal fishery. The sparsity of quantitative fisheries data, spectral confusion when modelling land-cover change, and absence of household survey data to assess livelihood activities remain major information gaps. Generalized recommendations for improving socio-ecological change studies in WIO estuarine systems are provided.

Modeling the Habitat Distribution of Acanthopagrus schlegelii in the Coastal Waters of the Eastern Taiwan Strait Using MAXENT with Fishery and Remote Sensing Data

Black sea bream, Acanthopagrus schlegelii, is among the most commercially valuable species in the coastal fishery industry and marine ecosystems. Catch data comprising capture locations for the gillnet fisheries, remotely sensed environmental data (i.e., sea surface temperature, chlorophyll-a concentration, and current velocity), and topography (bathymetry) from 2015 to 2018 were used to construct a spatial habitat distribution of black sea bream. This species is concentrated in coastal waters (&lt;3 nm) from December to April (spawning season). The maximum entropy (MaxEnt) method and corresponding habitat suitability index among seasons were used to clarify the species’ spatial distribution and identify the seasonal variations in habitat selection. The patterns corresponded closely to the changes in oceanographic conditions, and the species exhibited synchronous trends with the marine environment’s seasonal dynamics. Chlorophyll-a concentration and bathymetry substantially influenced (80.1–92.9%) black sea bream’s habitat selection. By applying the MaxEnt model, the optimal habitats were identified with four variables including depth and satellite-derived temperature, current velocity and chlorophyll-a concentration, which provides a foundation for the scientific assessment and management of black sea bream in coastal waters of the Eastern Taiwan Strait.

A study on improvement off isheries resources management through analysis of fishing capacity of coastal and offshore fisheries

A study on improvement off isheries resources management through analysis of fishing capacity of coastal and offshore fisheries

Spesifikasi dan Identifikasi Hasil Tangkapan Garok Rajungan di Pelabuhan Perikanan Pantai (PPP) Bondet Kabupaten Cirebon, Jawa Barat

Crayfish (Portunus pelagicus) is the leading export commodity of Indonesian fishermen. The increasing demand for exports and high selling prices have made fishermen at the Bondet Beach Fishing Port, Cirebon Regency, use garok crabs to maximize their catch. The purpose of this study was to identify tool specifications, catch yields, selectivity and productivity of garok crab fishing gear operated at the Bondet Coastal Fishery Port, Cirebon Regency, West Java. The research was carried out in April – June 2021. The method used was a case study method with quantitative descriptive analysis to determine the specifications of the tools and catches taken by interviewing fishermen. The results showed that the crab claws were included in the dredge gear category. Its components consist of body mouth, garok, frame, nets, and ropes of various sizes. The main catch of garok crab in Cirebon Regency consists of small crab (Portunus pelagicus), and by-catch in the form of shellfish, shrimp, cuttlefish, and demersal fish, with a total of 14 species. This tool is classified as non-selective because of the small size of the bag mesh construction (30 mm) so that this tool catches many species with large and small size fish caught. The average catch obtained from 5 trips was 23.8 kg, with the lowest catch on the 2nd trip, which was 19.7 kg and the highest on the 5th trip, which was 31.3 kg, while the average sweep area was 0.0040 km2 with an average productivity of 3.97 kg/hour and the highest catch rate value was obtained on the 5th trip, which was 5.21 kg/hour, while the lowest catch rate was found on the second trip, which was 3.28 kg/hour.

Faktor-Faktor yang Mempengaruhi Tingkat Kesejahteraan Nelayan Jaring Rampus (Bottom Gill Net) di Pelabuhan Perikanan Pantai (PPP) Bondet Kabupaten Cirebon, Jawa Barat

Bondet Coastal Fishery Port (PPP) is located in Cirebon Regency, which is adjacent to Grogol Village, Gunung Jati District, Cirebon Regency, where Grogol Village is one of the villages as a center for fishing fishermen with fishing gear mostly rampus nets. The rampus net (bottom gill net) is one of the fishing gear that can generate a source of income for fishermen in Grogol Village, Gunungjati District, Cirebon Regency which can be operated and produce fish almost every month. The purpose of this study is to explain the welfare of fishermen which can be analyzed in terms of income and expenditure. Bottom gill net fishermen. The method used in this research is descriptive method. This study uses a survey technique, which is a way of collecting data from a number of units or individuals at the same time. The data obtained were analyzed through financial analysis of the fishing business using rampus nets at the Coastal Fishery Port (PPP) Bondet, Cirebon Regency. The results showed that there was income inequality among Bottom Gill Net fishermen in Grogol village with a Gini coefficient value (inequality) of 0.24. Based on welfare indicators, according to BPS and the results of the summation of scores, it is known that bottom gill net fishermen in Grogol village have a high level of welfare (scores 20-24) with a total score of 23, and based on statistical analysis using NTN, the NTN value for bottom gill net fishermen in Grogol village is equal to 9,6 %, where NTN &gt; 1, it can be stated that all Bottom Gill Net fishermen respondents are prosperous. There is no difference in the final result of the level of welfare according to BPS and NTN.

Mackerel (Scomber australasicus) Reproduction in Northeastern Taiwan

Blue mackerel (Scomber australasicus) is a crucial target species for coastal fisheries in Taiwan, and additionally it has maintained its status as the highest-produced species. The timely measurement of spawning status is crucial for determining the correct management strategy for this species. The objective of this study was to determine size at maturity, fecundity, batch fecundity, and spawning frequency on the basis of samples collected from Nan-Fang-Ao fishing port in Yilan, during the spawning season from 2017 to 2019. Histological sections indicated that the blue mackerel were multiple spawners; a higher percentage of female fish spawned at the peak of the gonadosomatic index. The 50% sizes at maturity were 32.02, 32.13, and 29.64 cm. Mean total fecundity (batch fecundity) was 165 (103), 229 (96), and 210 (68) oocytes per ovary-free weight (g) for 2017, 2018, and 2019, respectively; fecundity was determined through observation of postovulatory follicles (POFs). The spawning frequencies (spawning fraction) in 2017, 2018, and 2019 were 3–10 days (0.13), 4–14 days (0.08), and 4–12 days (0.09), respectively. The spawning frequencies determined through the three estimated methods, namely the sums of (a) hydrated and Day 0 POFs; (b) Day 1+ POFs, and (c) all data combined, were 1 spawning event per 8, 10, and 9 days, respectively. The reproduction of the blue mackerel was greater in 2017 than it was in 2018 or 2019, as indicated by the higher batch fecundity and shorter spawning seasons. Environmental factors should also be considered as a major factor influencing successful reproduction and spawning season

Characterizing Changes in Participation and Diversification in Small-Scale Fisheries of Virginia, USA

Small-scale coastal fisheries are a key feature of Virginia’s cultural heritage, account for a significant portion of the state’s annual landings, and employ thousands of individuals. Despite the value of these fisheries, the number of commercial licenses sold has declined more than 15% since 1994. Using state license and permitting data, this research investigates participation and diversification in wild fisheries and marine-related economic industries through structural change and multiple correspondence (MCA) analyses. Results indicate evidence of instability in participation and diversification since the mid-1990s. The percentage of fishermen with diverse fishing portfolios accounts for less than half of those licensed and has not varied widely. Diversification into marine-related industries, however, has increased, likely due to aquaculture expansion. While some changes can be characterized as long-term trends, others indicate that participation and diversification may change considerably over shorter periods of time. MCA indicates evidence of similarity, in terms of license and permit holdings, between participants of several wild fisheries, including fishermen with a blue crab and finfish license or permit. Participation characteristics of individuals in marine-related business has changed since 1994 with more overlap between commercial fishing and seafood sales and processing in later years. Understanding participation and diversification patterns can aid managers in assessing impacts to individuals and fishing communities during adverse events and allow for consideration of social identity in management decisions. Furthermore, understanding and contextualizing resource dependency of commercial fishers, as well as the connectivity across species and sectors, may support the long-term goals of ecosystem-based management.