Assessment Of Fishery Resources Research Articles

Genetic characterization of minor carp (Labeo gonius) from Indian rivers revealed through mitochondrial ATPase 6/8 and D-loop region analysis: implications for conservation and management

India is the habitat of many freshwater fish species that make a significant contribution to endemism. However, the native species population is declining at a very fast rate due to pollution, habitat loss or degradation, new species introduction, hydrologic alterations, and overfishing. The minor carp, Labeo gonius, is one of the important fish species in the Indian river systems and holds enormous potential in culture fisheries. Therefore, the precise status of population structure is a prerequisite for the management of the species. In the present study, we assessed the potential of mtDNA ATPase 6/8 and D-loop regions as markers to determine the genetic diversity and phylogeography of L. gonius from Indian rivers. We have selected five major Indian rivers for investigation which could represent geographically distant populations of the studied fish. A total of 210 ATPase 6/8 sequences (842 bp) and 203 D-loop region sequences (683 bp) of L. gonius from the five major Indian rivers were submitted to NCBI. Results revealed that ATPase 6/8 has 17 haplotypes and 70 polymorphic sites with an overall haplotype diversity of 0.560 ± 0.036 and nucleotide diversity of 0.00347 ± 0.00. Furthermore, D-loop analysis revealed 58 haplotypes, 67 polymorphic sites, 0.954 ± 0.006 overall haplotype diversity, and 0.01914 ± 0.00 nucleotide diversity. The hierarchical AMOVA analysis indicated that a high proportion of the genetic variation (76.46% and 70.22% for the D-loop and ATPase 6/8 regions, respectively) was attributed to among-population variation under gene pool-1 (considering all the stocks from Ganga, Brahmaputra, Teesta, Narmada, and Mahanadi as a single pool). Furthermore, in gene pool-2, samples were divided into two groups: group 1 (Himalayan rivers)—Ganga, Brahmaputra, and Teesta; and group 2 (peninsular rivers)—Narmada and Mahanadi. Genetic variations in the D-loop and ATPase 6/8 regions were found among populations within groups at 70.65% and 53.48%, respectively. Haplotype network analysis revealed that there were significant differences in distributions and frequencies. The observed unique haplotypes might be useful for differentiating the stocks. In brief, the present study suggested that the D-loop and ATPase 6/8 regions are potential markers and represent a significant contribution to the genetic characterization of the minor carp L. gonius from major Indian rivers. Moreover, the L. gonius population along the east coast especially in the Himalayan rivers (Ganga, Brahmaputra, and Teesta river basin) is found to be genetically more diverse. The results would provide a scientific basis for the assessment of fisheries resources and management of this important species.

An assessment of demersal fisheries by trawling in less than 50 m of water off Egypt’s Mediterranean coast

Trawl fishing is identified as one of the most significant factors that could affect the diversity of demersal fish groups but not for all depth strata. Since the increased exploitation of Non-Indigenous Species (NIS) has caused the trawl fishing grounds to shift towards shallower seas where their biomass density is maximum, this study aimed to assess demersal fisheries by bottom trawls in the Mediterranean water off Egypt at depths less than 50 m. In this study, data from eight bottom-trawl hauls were used to describe the diversity of the demersal fish catch. The hauls varied in their species composition and both in the number and the weight of individuals. The length frequency distribution of the most occurred species was studied. A total of 87 species were identified in the catch, out of which 32 were recognized as NIS. The percentages of most of the NIS decreased from the east to the west of the surveyed area. There are always changes in fish diversity because of increasing fishing efforts on demersal fish communities, but not for all depth strata, therefore, a monitoring program has to be designed for better assessment of fisheries resources in the Mediterranean water off Egypt.

Estimating Spatiotemporal Fishing Effort of Trawlers with Vessel-Monitoring System Data: A Case Study of the Sea Area of the Bohai Sea and the Yellow Sea, China

Measuring the distribution of the fishing effort of trawlers is of great significance for describing marine fishery activities, quantifying fishing systems in terms of marine ecological pressure, and revising the regulations of fishing. The purpose of this paper is to develop an efficient learning algorithm to detect the fishing behavior of trawlers to analyze the distribution of fishing effort. The vessel-monitoring system data of more than 4600 trawlers from September 2019 to April 2023 were used for feature extraction. According to the spatiotemporal information provided by the vessel position data, 11-dimensional features were extracted to form the feature vectors. A Slime Mould Algorithm-optimized Light Gradient-Boosting Machine (SMA-LightGBM) algorithm was proposed to classify the feature vectors to recognize fishing behavior. The presented method showed a remarkable generalization ability and high accuracy, sensitivity, specificity, and Matthews correlation coefficient in the test results, with scores of 98.23%, 98.75%, 97.75%, and 0.9646, respectively. Subsequently, the trained model was used to identify the fishing behavior of trawlers belonging to the coastal provinces of the Bohai Sea and the Yellow Sea in the sea area of 117° E~132° E, 26° N~41° N. The fishing effort was calculated and evaluated according to the fishing behavior recognition results. The mean absolute error was 0.3031 kW·h, and the coefficient of determination score was 0.9772. The thermal map of the fishing effort of the trawler was mapped, and the spatiotemporal characteristics were estimated in the region of interest from 2019 to 2023 with a spatial resolution of 18 degree × 18 degree. This method is an efficient way of analyzing the spatiotemporal characteristics of the fishing effort of trawlers. It provides a quantitative basis for the assessment of fishery resources and can inform fishing policies.

The challenges of modelling and assessing fisheries resources

Abstract Many years after the publication of Beverton and Holt’s on the Dynamics of Exploited Fish Populations in 1957, many of the problems that they highlighted remain unsolved. For example, accurately estimating critical biological and fishing processes such as growth, natural mortality, recruitment, and selectivity continues to be challenging. Despite the lack of progress in some areas, there have been advances in our understanding of other areas of fisheries modelling and analysis, including the development of integrative studies of marine resources for the application of an ecosystem-based fisheries management. In this context, ICES Journal of Marine Science solicited contributions to the themed article set (TS) “Advances and challenges in the modelling and assessment of fishery resources”. Here, we summarize the contributions included in this TS that provide examples of emerging tools that are able to account for different issues of a stocks’ assessments and integrated analyses.

Research and application of fishery resource assessment based on particle filter algorithm physical habitat model

In order to solve the problem of accurately and robustly recovering fish trajectories from videos, the author proposes a physical habitat assessment model for fishery resources based on particle filter algorithm. The idea of “group tracking” was proposed, which divides all targets into several groups based on their mutual distance and processes different groups independently and in parallel, avoiding the extremely high dimensionality caused by estimating all zebrafish parameters simultaneously. The parameters of all individuals in the same group are estimated together, and it handles occlusion by modeling the interaction and occlusion of objects in the same group. The experimental results show that from frame 16 to frame 21, two fish suddenly turn around, especially the fish marked in red; From frame 34 to frame 42, these two fish interact for the first time, but do not intersect; From frame 49 to frame 58, these two fish interact and pass through each other for the second time. The algorithm proposed by the author, GCT, and contrast algorithm CT, can effectively handle the protruding and directional motion of fish. Conclusion: The algorithm is accurate and reliable.

Evaluation of Biological Reference Points of Two Important Fishery Resources in the East China Sea

Fishery resources play an important role in the national economy and ecological diversity in China; it is of great significance to evaluate and rationally exploit the fishery resources. Most fisheries off the coast of China are data-limited, as the complex assessment models are not suitable for its resource assessment. Therefore, data-limited models for fishery resources assessment in China are among the current research hotspots. In this paper, two new data-limited assessment models (Bayesian state–space implementation of the Schaefer production model (BSM) and Monte Carlo MSY estimation model (CMSY)) were used to evaluate the fishery resources of Scomber japonicus and Muraenesox cinereus in the East China Sea. The results showed that the estimated value of MSY of S. japonicus was 220 × 103 t to 240 × 103 t, the estimated value of F/FMSY was greater than one, and the estimated value of B/BMSY was very close to one, indicating that the fishery in the East China Sea had been overfished. The estimated value of MSY for the M. cinereus fishery in the East China Sea ranged from 140 × 103 t to 170 × 103 t. The estimated value of F/FMSY at the biological reference point was greater than one and the estimated value of B/BMSY was less than one, indicating that the fishery had been overfished and resources had declined. Both models can be used for data-limited fisheries offshore of China. To better understand the impact of uncertainty on fishery resource assessment, more research should be carried out on these two data-limited assessment models.

Acoustic Assessment of Fishery Resources in Jinwan Offshore Wind Farm Area

After more than ten years of offshore wind farm (OWF) construction, the total installed capacity of China ranks first in the world. The effect of OWF on fish communities—to attract or banish—differs among fish species and wind farms. Studies on the effects of OWFs are limited in China and results from other regions may not be transferable due to different environmental and biological conditions. In October 2019, an acoustic survey was conducted in Jinwan OWF, outside the Pearl River Estuary, northern South China Sea, China, to assess the fish resources (biomass and abundance), community diversity, and distribution information of this area. According to the Index of Relative Importance (IRI), Harpadon nehereus and Brionobutis koilomatodon were the dominant fish species in the study area. The mean Shannon–Weiner diversity index was 1.74. The mean Margalef richness index and Pielou uniformity index were 2.51 and 0.84, respectively. The ABC curve indicated that the fish community was undisturbed. The mean acoustically-derived biomass and abundance densities were 195.40 ± 254.32 kg/km2 and 6506.83 ± 11,098.96 individuals/km2, respectively. The fishery resources had evident aggregate distribution patterns, and the southern part of the study area had more biomass than the northern part. Seven environmental factors were selected by canonical correspondence analysis (CCA) analysis to reveal the correlation between fish assemblages and environmental factors, including nitrate (NO3−), ammonium (NH4+), dissolved oxygen (DO), water depth, pH, Chlorophyll a (Chl a), and phosphate (PO4+). However, the CCA only accounted for 45.49% of the total variation, indicating that other unexplained stresses affect the fish assemblage in Jinwan OWF. This is the first study to examine the fish distribution patterns and community structures of the Jinwan OWF area. In addition, it will help all sectors of society to more scientifically and objectively understand offshore wind farm projects. In future studies, control areas with more trawl samples can be set up to explore the long-term impact of OWF facilities on local fish communities.

Comparison of Two Types of Survey Designs for Acoustic Estimates of Fish Resources in the Three Gorges Reservoir, China

Pre-planning for a rational survey design is essential to improve the reliability and efficiency of the acoustic assessment of fishery resources in large water bodies. In this study, we compared the differences in acoustic estimates of fish resources between triangular and parallel transect designs in the Three Gorges Reservoir (TGR, China), aiming to provide a reference for fishery acoustic survey planning in such canyon-shaped reservoirs. We conducted hydroacoustic surveys using an echosounder (SIMRAD EY60, 120 kHz) in the Yangtze mainstream near the dam and an adjacent tributary with triangular and parallel designs. The independent samples t-test showed that the acoustic estimates of fish density were not significantly different between these two types of survey designs for both mainstream and tributary. The Fisher’s exact test indicated that there was no significant difference in fish size distributions, as measured by target strength (TS), between survey designs either. In view of reducing time spent in nearshore areas to improve efficiency and ensure safety, we recommend that the triangular design with reliable coverage be given priority for hydroacoustic sampling in the TGR and similar canyon-shaped reservoirs, especially when sampling at night.

Revealing the Effectiveness of Fisheries Policy: A Biological Observation of Species Johnius belengerii in Xiamen Bay

The rapid development of China’s economy has brought tremendous pressure to the marine ecosystem, and about 57% of marine fish populations have been overexploited or collapsed. A series of fisheries policies have been implemented successively to improve the decline of resources. Over the past decade, the fisheries sector has particularly increased focus on resource and ecosystem sustainability, which has led to the wider use of stock management policies in China. Therefore, fishery resource assessment is crucial, such as assessing the long-term changes in biological information. This study is based on biological characteristics of Johnius belengerii captured by bottom trawls in Xiamen Bay during two periods, beginning in 2006 and 2016. Length composition, length–weight relationship, growth, mortality, sexual maturation, and feeding intensity were analyzed. The changes in biological characteristics show that there is a phenomenon of improvement in the later period, of which the changes are closely related to a series of fisheries management strategies, such as setting closed fishing periods and non-fishing areas, and establishing fishery restoration marine protected areas. This result seems to reveal the effectiveness of a long-term series of fisheries policies. It can provide an important basis and visibility for management effectiveness.

Stock Assessment of Four Dominant Shark Bycatch Species in Bottom Trawl Fisheries in the Northern South China Sea

Sharks occupy an important ecological niche in marine ecosystems. As top predators, they can restrict and control the behavior, numbers and composition of other species through downward effects, and play an essential role in ecosystem stability. Shark fishery data are limited, and for most Chondrichthyes species there is no formal fishery resource assessment at a global level. In this study, we applied the length-based Bayesian biomass (LBB) estimation method to assess the stock status of four common shark bycatch species of which more than 100 samples were collected in coastal waters of the northern South China Sea. Estimates of the length of 50% of individuals captured by gear/the length at first capture that maximized the catch and biomass (Lc/Lc_opt) of a species ranged from 0.49 to 1.4; the draughtsboard shark Cephaloscyllium sarawakensis had the highest value, and the shortnose dogfish Squalus brevirostris had the lowest. Estimates of the collected biomass/biomass of the maximum sustainable yield (B/BMSY) ranged from 0.86 to 1.9. Both C. sarawakensis and the spadenose shark Scoliodon laticaudus were fully exploited, while the spatulasnout catshark Apristurus platyrhynchus and S. brevirostris were in good condition. To verify the stability of the LBB, length frequency data for the most common species S. laticaudus were divided into different size-class intervals; simulations revealed estimated parameters based on these to be insensitive to differences in intervals, except for the smallest (10 mm), which did not affect evaluation results. These results can be used to provide a scientific basis on which shark fisheries in this region can be managed and prior parameters for related resource assessment methods can be determined.

Research on Fishery Resource Assessment and Sustainable Utilization (FRASU) during 1990–2020: A bibliometric review

Fishery resource assessment and sustainable utilization (FRASU) is a topic of global concern. Although fishery resources are highly profitable, these are linked to environmental and socio-economic issues. In the context of increasing demand for fishery sustainability, fishery resource assessment is essential to support scientific fishery resource management. Bibliometric techniques and the Web of Science (WOS) database from 1990 to 2020 were employed to analyse the journals, authors, institutions, countries, cited references, and keywords using the CiteSpace (5.3. R11) software and standard bibliometric indicators. A quantitative review of global research related to FRASU identified recent important research topics and allowed prediction of research trends, as well as confirmed that it is an increasing area of concern. A total of 1631 publications were retrieved from 1990 to 2020, and the most active journals, countries, authors and institutions in the field were identified. 'Fisheries Research', 'Ocean Coastal Management' and 'ICES Journal of Marine Science' are the main journals that publish FRASU research. European and North American countries are the main publishers in this field, while the contribution of Asian countries has gradually increased. It is expected that China, Japan, Brazil, and India will make increasingly significant contributions to this field. Groupers, size, catch-per-unit-effort and genetic diversity are important core research areas in this field. Policy, maximum sustainable yield, small scale fisheries, ecosystem management and sustainability frameworks are identified as potential emerging research areas. Furthermore, five key areas of current research trends on FRASU were identified: problems with fishery resource assessment, impact of changes in marine biodiversity on ecosystem services, influence of fishery resource changes on the structure of food webs, ecosystem-based fishery management, and frameworks for sustainable development of fishery resources. The findings from this bibliometric study provide insight into in the growth of research publications and changes in hot areas in the field of FRASU over the past 30 years, including global trends in emerging areas of research.

Composited FishNet: Fish Detection and Species Recognition From Low-Quality Underwater Videos

The automatic detection and identification of fish from underwater videos is of great significance for fishery resource assessment and ecological environment monitoring. However, due to the poor quality of underwater images and unconstrained fish movement, traditional hand-designed feature extraction methods or convolutional neural network (CNN)-based object detection algorithms cannot meet the detection requirements in real underwater scenes. Therefore, to realize fish recognition and localization in a complex underwater environment, this paper proposes a novel composite fish detection framework based on a composite backbone and an enhanced path aggregation network called Composited FishNet. By improving the residual network (ResNet), a new composite backbone network (CBresnet) is designed to learn the scene change information (source domain style), which is caused by the differences in the image brightness, fish orientation, seabed structure, aquatic plant movement, fish species shape and texture differences. Thus, the interference of underwater environmental information on the object characteristics is reduced, and the output of the main network to the object information is strengthened. In addition, to better integrate the high and low feature information output from CBresnet, the enhanced path aggregation network (EPANet) is also designed to solve the insufficient utilization of semantic information caused by linear upsampling. The experimental results show that the average precision (AP)0.5:0.95, AP50 and average recall (AR)max=10 of the proposed Composited FishNet are 75.2%, 92.8% and 81.1%, respectively. The composite backbone network enhances the characteristic information output of the detected object and improves the utilization of characteristic information. This method can be used for fish detection and identification in complex underwater environments such as oceans and aquaculture.

Assessment of fishery resources using environmental DNA: Small yellow croaker (Larimichthys polyactis) in East China Sea.

Species distribution monitoring and biomass assessment are crucial for fishery management and resource conservation. However, traditional methods such as motor trawling are costly and less effective than the novel environmental DNA (eDNA) approach. This study employs eDNA approach to investigate horizontal and vertical distributions of small yellow croaker (Larimichthys polyactis), an economically important species, in the East China Sea. The analysis of 171 eDNA samples collected from 44 stations using the species-specific primers and Taqman probe suggests a presence of small yellow croaker at 28 sampling layers in 44 stations. Significant differences in croaker eDNA concentrations were revealed among sampling stations and layers, consistent with previous findings through motor-trawl capture offshore and nearshore ichthyoplakton surveys, indicating small yellow croaker exhibits strong regional distribution and layer preference. In addition, we found a high eDNA concentration of small yellow croaker in the surface waters beyond the motor-trawl prohibition line, which confirms spawning grounds have been expanded from nearshore to offshore areas. Such expansion of spawning grounds could be a response by small yellow croaker to stressors such as overfishing, climate change, and nearshore environment contamination. To identify environmental variables potentially associated with small yellow croaker presence and absence, we conducted a correlation analysis between eDNA concentration and environmental variables, and the results provide a guideline for further investigation of fishery resources in the future. In conclusion, this study demonstrates the power of the eDNA approach in monitoring small yellow croaker at extensive geographic scales. The developed protocols and the findings are expected to assist in long-term monitoring and protection programs and benefit sustainable fishery in small yellow croaker.

Assessment of fishery resources using environmental DNA: The large yellow croaker (Larimichthys crocea) in the East China Sea

Fisheries management and resource conservation rely upon accurate information on the distribution and abundance of major species. The large yellow croaker (Larimichthys crocea) was once one of the most economically important marine fish in East Asia; however, its wild fishery resource has collapsed since the 1980s. Until recently, the natural resources of L. crocea started to increase due to the practice of stock enhancement and summer fishing moratorium. In this study, we developed the species-specific primers and probe and investigated the distribution and abundance of L. crocea using the environmental DNA (eDNA) approach. We collected 171 samples from 44 stations (190,467 km2 sea areas) in the East China Sea and detected 96 positive eDNA samples of L. crocea (56 %) at 29 stations (66 %). We found a significant difference in eDNA concentrations among different stations, indicating a regional distribution in L. crocea. We observed vertical variations in the eDNA concentrations of L. crocea among different water layers and detected the eDNA signals in water depths around 40 m and the bottom at multiple stations. We discovered eDNA hotspots with high concentrations in the Yushan fishing ground, which suggesting an offshore spawning ground might have been established possibly in response to nearshore environmental pollution and overfishing. We evaluated the effect of environmental variables on the distribution of L. crocea, found total depth and temperature were significantly correlated with the eDNA presence and concentration, and built a general linear model for the presence or absence prediction of L. crocea with environmental parameters. This study demonstrates the robustness of the eDNA approach in investigating and monitoring natural resources of a crucial marine fish and thus contributes to the long-term assessment of stocking and other strategies in fisheries enhancement.

Characterisation of artisanal catches in selected fishing areas of the Lower Tana Delta and Malindi-Ungwana Bay, Kenya

Shore-based assessment of fisheries resources in Ngomeni, Kipini and Ozi fishing areas of Malindi-Ungwana Bay and the Lower Tana Delta on the north coast of Kenya was conducted from January to December 2017 to establish catch composition, species richness, and fishing effort (catch-rate, number and types of fishing gears and crafts) in the marine, estuarine and riverine habitats. Distinct catch composition (R = 0.27, P < 0.05) was observed across the three habitats. Catch composition differed significantly spatially and seasonally across the three fishing areas, and between the north east (NE) and south east (SE) monsoon seasons (R = 0.332, P < 0.05). The wolf herring, Chirocentrus dorab, was the most abundant fish species in Ngomeni, centrally located in Malindi-Ungwana Bay, while the catfishes, Arius africanus and Clarias gariepinus, were the most abundant species in Kipini and Ozi, respectively. Gillnets operated from dhows (mashua) and fibre-reinforced plastic (FRP) boats in Ngomeni (marine), and canoes using-basket traps in Ozi (riverine), landed significantly larger Spanish mackerel, Scomberomorus commerson, and sea catfish, Arius africanus (Kruskal Wallis test: Df = 2; F = 197.141; p < 0.001; Df = 2, F = 490, p < 0.001), respectively. Species diversity by area in combination with habitat and type of fishing craft showed higher diversity for Ngomeni in the marine habitat with mashua fishing crafts than in Kipini. Significantly different catch rates (Df = 2, F = 10.43, p<0.001; Df = 1, F = 5.897, p < 0.021) were observed in the three (3) fishing areas and during the NE monsoon and the SE monsoon, respectively. Canoes were the most common fishing craft used, especially in Ngomeni, accounting for 37.1%, and 97.5% in Ozi, while mashua crafts accounted for 44.5% of the total fishing craft in Kipini. Monofilament nets were most common in Ngomeni (34.0%) while basket traps dominated the Ozi site at 63.6%. The Kipini area was dominated by handlines (28.8%). It is therefore evident that the three (3) fishing areas of the Malindi-Ungwana Bay and Lower Tana Delta showed significant differences in catch composition and size of fish caught, attributed partly to the variation in habitat types and fishing methods between the sites. Overall, the Ngomeni area was characterized by more advanced fishing craft with the majority powered by engines, including mashua and FRP boats, compared to Kipini and Ozi fishing areas where canoes were dominant.

Beak morphological and growth characteristic of Sthenoteuthis oualaniensis in the northwest Indian Ocean in winter and spring

Beak is one of the most important hard tissues of cephalopods, and thus is widely used in the study of cephalopod fisheries ecology and fishery resource assessment. With 1009 Sthenoteuthis oualaniensis samples collected by Chinese light falling-net fishery during February to May in the northwest Indian Ocean, we examined the morphologic and growth characteristics of beak. Results of the principal component analysis showed that the upper hood length (UHL), the upper crest length (UCL), the upper lateral wall length (ULWL), the lower crest length (LCL), the lower wing length (LWL) and the lower lateral wall length (LLWL) could be used as the morphological cha-racteristic parameters to examine the morphological changes of the beak. Results of the analysis of covariance (ANCOVA) showed that there were significant differences in the relationships between all of the morphological characteristic parameters and mantel length (ML) for males and females except UCL. There were significant differences in the relationships between all of the morphological characteristic parameters and body weight (BW) for males and females. The relationships between LCL, UCL and ML were optimally described by the linear functions. Power functions were best for UHL, LWL and linear functions were best for ULWL, LLWL for females. The relationships between ULWL and ML were optimally described by power functions, while the logarithm functions were best for UHL, LLWL and LWL for males. The relationships between all of the morphological characteristic parameters and BW were optimally described by the power functions for females, while the logarithm functions for males except the power function for ULWL. Our results provided scientific basis for the research of the fisheries ecology and stock assessment for S. oualaniensis.

Population dynamics and sustainability of the spiny lobster (Panulirus meripurpuratus Giraldes & Smyth, 2016) fishery on the Amazon continental shelf

The assessment of fishery resources is key to the development of management strategies for exploited stocks. Analysis of specific parameters provides information regarding the state of the stock and indicators of exploitation levels. The aim of the present study was to analyse the growth and mortality parameters, as well as investigate the exploitation status, of Panulirus meripurpuratus caught on the Amazon coast, northern Brazil. Growth parameters and stock assessment were estimated using R with bootstrapping and FISAT II, based on cephalothorax length–distribution frequency. Specimens were collected by the commercial lobster fishery off the coast of the states of Pará and Amapá between 2001 and 2002. The results indicate that the P. meripurpuratus stock assessed is composed of individuals with low growth rates and high estimates of maximum asymptotic length, with relative longevity of 21.37 years. The exploitation rate was operating at near the maximum limit of sustainability in 2001 and 2002. This is the first estimate of the exploitation status of P. meripurpuratus on the Amazon coast. We strongly recommend new monitoring efforts and further studies to support the conservation and management of the spiny lobster stock.

Fish diversity, physicochemical parameters of soil and water, length-weight relationships and condition factor of fishes of Urbashi Dam Karak, KPK, Pakistan

Biodiversity is the difference between life forms that highlights the abundance and significance of living organisms in the ecosystem. Physiochemical parameters of water and soil have utmost importance in the dispersion of aquatic life and also in the breeding of aquatic organisms. Studies on the length-weight relationship are very important to fishing biology and stock assessment of fisheries resources. This research was carried out to elaborate on fish diversity, physicochemical parameters of water and soil, length-weight relationships (LWR) and condition factor (K) of fishes of the Urbashi dam in Karak, Khyber Pakhtunkawa, Pakistan. Fish samples were obtained by the help of local fisherman through nets, gill nets, drag nets, and cast nets from October 2020 to July 2021. The specimens were preserved in a 10% formalin solution. The length and weight of fish samples were determined with the help of a measuring tape and a digital balance. The physiochemical parameters like conductivity, PH, temperature, color, taste, TS, and TDS of water and soil were examined by collecting (n=3) samples from different sites of the Urbashi dam, i.e., the start, mid, and end. During the current research study, 7 species belonging to family Cyprinidae were known at species level. The obtained values of each parameter such as conductivity, PH, temperature, color, taste, TS and TDS of water and soil were compared with the standared values set by the World Health Organization (WHO). According to the findings of this study, all physiochemical parameters were found to be within permissible ranges and non-harmful for culturing and growing fishes, as recommended by the (WHO). Labeo rohita and Tor khudree had positive allometric growth in the length-weight relationship (LWR), while Catla catla, Cirrhinus mrigala, Hypopthalmichthys molitrix, and Cyprinus carpio had negative allometric growth and Carassius auratus had isometric growth.The highest value of condition factor (K) was recorded in Carassius auratus, while the lowest was in Catla catla. Hence, the study explore useful information of ichthyofauna of Urbashi dam, which is beneficial for fisheries management as well as for further research. After analysis, it was concluded from the results that the physiochemical parameters of the water and soil of Urbashi dam lie within a suitable range which is suggested by WHO for fish growth, survival, and reproduction. Hence, the study aimed to enhance some more information in the aquaculture department of the country to narrate the population conditions of the fish species in the Urbashi dam.

Assessment of Fishery Resources in the Lagonoy Gulf, Philippines

Assessment of Fishery Resources in the Lagonoy Gulf, Philippines

Assessment of Fisheries Resources in the Babuyan Channel

Assessment of Fisheries Resources in the Babuyan Channel