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Shellfish reefs, characterized by habitat‐forming bivalves, are increasingly recognized as globally significant coastal ecosystems and valuable fish habitats. Shellfish reefs provide structural refugia, foraging grounds, and nurseries for diverse fish communities, including species with socioeconomic value. However, efforts to quantify the value of shellfish reefs as fish habitats are challenged by the limited and fragmented knowledge of published monitoring practices. Here, we systematically assess 116 peer‐reviewed studies to provide a global overview of literature evaluating fishes in these ecosystems. Research was unevenly distributed, with 67% of the studies concentrated in the United States, 61% on restored reefs, and 83% focused on oyster reefs. Few studies have directly compared fish communities between natural versus restored, or intertidal versus subtidal shellfish reefs. Methods to quantify fishes varied based on research objectives, tidal zonation, and targeted subsets of the fish assemblages. Gill nets, substrate trays, and underwater video stations were the most common methods, with 44% of studies deploying more than two methods to survey fish communities. Differences in the monitoring methods, research designs, and variables reported were also synthesized and discussed. From this review, we identified knowledge gaps and monitoring trends in fish community assessments that can guide future shellfish reef research and conservation efforts. [ABSTRACT FROM AUTHOR]

Kishorekumar, M.; Jayakumar, N.; Jawahar, P.; Neethiselvan, N.; Padmavathy, P.; Karuppasamy, K.; Sudhan, C., and Chandravanshi, S., 2024. Length–weight relationship of nine elasmobranch species landed along the south Tamil Nadu coast, India. Journal of Coastal Research, 40(6), 1160–1165. Charlotte (North Carolina), ISSN 0749-0208. The present study was conducted to establish the length–weight relationship of nine elasmobranch species from the coast of southern Tamil Nadu, India. In total, 2686 specimens of nine species of elasmobranchs belonging to five orders, seven families, and eight genera were collected fortnightly from commercial catches with different fishing gear, such as trawl net, gill net, and deep-sea longline, from the Thoothukudi, Mandapam, and Thengapattanam fishing harbors from December 2022 to November 2023. The results showed that most species exhibited positive allometric growth and that values of b were within the expected range of 2.5 to 3.5. The maximum b value (3.17) was observed for male Pateobatis bleekeri. The total length–weight relationship or disc width–weight relationship showed good fit with r2 values, varying from 0.8374 to 0.9969. The calculated b values in the current study showed that all males, females, and combined sexes of P. bleekeri, Aetobatus ocellatus, and Acroteriobatus variegatus showed negative allometric growth (b < 3). In the study, a new maximum total length is reported for P. bleekeri, and this study provides the first estimate,, of the length–weight relationship for the critically endangered species A. variegatus. The study provides baseline information for biological studies, stock assessment and management, and conservation of elasmobranch resources in a sustainable way along this coast. [ABSTRACT FROM AUTHOR]

Dhanabalan, S.; Neethirajan, N.; Natarajan, J.; Muthupandi, K.; Thangaraji, R.; Sethuraj, A., and Julin, A.S., 2024. Gillnet selectivity for the Coromandel flying fish, Hirundichthys coromandelensis (Hornell, 1923), along the Nagapattinam coast, southeast coast of India. Journal of Coastal Research, 40(6), 1137–1143. Charlotte (North Carolina), ISSN 0749-0208. The Coromandel flying fish, Hirundichthys coromandelensis, forms a seasonal fishery along the Nagapattinam coast of Tamil Nadu, southeast coast of India, from March to August. The peak fishing season for this fish in the small-meshed gillnets operated along the Nagapattinam coast was found to be the month of June. Small-meshed gillnets, locally known as "Kolavalai," with different mesh sizes of 30 mm (net A), 32 mm (net B), and 34 mm (net C) were found to be operated for the capture of H. coromandelensis. Length frequency data collected from March 2023 to August 2023 were used to create gillnet selectivity curves for H. coromandelensis. The length at first capture (Lb) of this species was found to be 149 mm, 160.9 mm, and 172.8 mm for net A, net B, and net C, respectively. The mean selection length (Lc) was estimated as 179.9 mm, 191.9 mm, and 203.9 mm for net A, net B, and net C, respectively. Further, the escapement length (Ld) was found to be 211.8 mm, 223.7 mm, and 235 mm for net A, net B, and net C, respectively. The value of gill selection factor for H. coromandelensis was estimated as 5.99. The mesh sizes for the commercial exploitation of commercially significant length groups (195 mm) and fishable length groups (190 mm) were estimated as 32.5 mm and 31.7 mm, respectively. The selectivity study revealed that among the three different mesh sizes of gillnets analyzed, net A with a mesh size 30 mm needs to be discouraged, as it was found to capture mainly immature and maturing specimens of H. coromandelensis. [ABSTRACT FROM AUTHOR]

Microplastics are emerging pollutants of global concern, and their presence in the aquatic environment poses a serious risk for aquatic biota. While many studies have been conducted on the presence of microplastics in marine habitats, little research has been done in freshwater African reservoirs on microplastic pollution and their impacts on fish within the subtropical regions. To bridge this gap, the current study investigated microplastic abundances and distribution in freshwater fish within Nandoni reservoir, South Africa, across two seasons (i.e., hot–wet, cool–dry). Fish were randomly sampled using seine and gill nets from seven sites within the reservoir. In the laboratory, fish were then sorted according to taxa before dissecting them to remove the gills and the gastrointestinal tract (GIT). The organs were digested using hot hydrochloric acid and hydrogen peroxide, and the microplastics were classified according to their colours and shapes. Among the 94 fishes (i.e., 8 species) examined, microplastics were detected in 86.6% of the eight species caught. Microplastics were dominant in the gills and GIT during the cool–dry and hot–wet seasons, respectively. High microplastic abundances were found in the gills of Micropterus salmoides and the GIT of Coptodon rendalli, where fibres and the transparent colour were the most dominant. The results further showed high microplastic abundances in benthopelagic feeders highlighting that habitat influences fish consumption of microplastics whether directly or indirectly. Significant differences were observed in the feeding zone and season for all microplastic types. Microplastic sources in the reservoirs could be due to anthropogenic activities such as illegal dumping, fishing, and agriculture. Thus, there is a need for further investigation into the relation of fish weight, fish sex and body in relation to microplastic pollution. The highlighted ecological factors should be taken into consideration for future research and management actions aimed at mitigating and protecting the negative impacts of microplastic pollution on environmental and human health. [ABSTRACT FROM AUTHOR]

Panulirus penicillatus is a lobster species primarily found in insular regions but also recorded in coastal continental zones of various countries along the American Pacific. This study reports P. penicillatus for the first time in the coastal area of Manabí Province, mainland Ecuador. Previously, its presence was known only in the Galápagos Islands, where it is a commercial species. The record is based on two adult individuals of P. penicillatus, both collected in October 2023 from fishing activities, one through nighttime apnea diving and the other via artisanal fishing using a gillnet. [ABSTRACT FROM AUTHOR]

To address issues such as insufficient fishing vessel data records, low energy efficiency, and high emissions, this study constructs and validates a predictive model for the maximum power limitation of fishing vessels. Using gillnet fishing vessels as a case study, the Energy Efficiency Existing Ship Index (EEXI) reference line formula for gillnet fishing vessels is fitted using the nonlinear least squares method. Sensitivity analysis reveals power's impact on fishing vessels' energy efficiency. The maximum power calculation method for fishing vessels is derived by combining the EEXI calculation formula, the reference line formula, and the power-speed relationship. Three regression prediction models--Decision Tree, Random Forest, and Gradient Boosting--are used to construct prediction models with gross tonnage, length between perpendiculars, and gross tonnage and length between perpendiculars as inputs, respectively. Results show that power significantly impacts the energy efficiency of fishing vessels. The EEXI reference line formula for gillnet fishing vessels has MAE, MSE, MAPE, RMSE, and R^2 values of 13.3518, 369.5200, 18%, 19.2229, and 0.6366, respectively. The Random Forest regression model with gross tonnage as input performs best in predicting the maximum power limitation of gillnet fishing vessels, with MAE, MSE, MAPE, RMSE, and R^2 values of 5.61423, 6152.40982, 1.90888%, 78.43730, and 0.633062393, respectively. This paper provides a reliable calculation method and prediction model for the maximum power limitation of fishing vessels, offering systematic technical support and decision-making references for limiting the maximum power of fishing vessels. [ABSTRACT FROM AUTHOR]

Inland fisheries development in South Africa has been proposed to improve rural livelihoods and food security. However, inland fisheries are susceptible to collapse through overfishing. Therefore, establishing biological reference points for these fisheries is essential for long-term sustainability. Here, spawner-biomass-per-recruit (SBR) analysis was used to set biological reference points for a gillnet fishery targeting the rednose labeo Labeo rosae and Mozambique tilapia Oreochromis mossambicus at Flag Boshielo Dam on the Oliphants River in Limpopo Province, South Africa. Both species are currently exploited at the impoundment by subsistence fishers that keep their entire catch. The current yields are estimated at 59 and 172 g yr−1 for L. rosae and O. mossambicus, respectively. The per-recruit analysis showed that age-at-first-capture for both species should be 4 years, at minimum lengths of 280 mm TL and 250 mm TL for L. rosae and O. mossambicus, respectively, with fishers using a minimum mesh size of 100 mm to reduce the risk of stock collapse. To maintain a SBR value greater than 25% of a pristine population, the L. rosae yield could be increased to 98 g yr−1, while the O. mossambicus yield could be increased to 176 g yr−1, following implementation of the recommended mesh size and size limits. A per-recruit analysis for O. mossambicus that includes recruitment variability and error to accurately calculate the biological reference points is recommended. [ABSTRACT FROM AUTHOR]

Gill disease is a major threat to aquaculture of Atlantic salmon, with an unknown and likely underestimated contribution from cnidarians such as jellyfish and biofouling hydroids. To better understand the risk and thus enable mitigation, technology for the certain identification of cnidarian-related gill damage is needed. We used the hydroid Ectopleura larynx in a case study to determine whether the exposure of salmon to nematocyst-bearing hydrozoans can be deducted via non-destructive PCR-based methods. In a field experiment, we evaluated (i) whether swabbing the inside of the gill operculum in farmed Salmo salar and subsequent PCR analysis can provide quantifiable information about the presence of E. larynx material in the gill chamber and, if so, (ii) whether the screening results correlate with histological assessments of gill damage. The developed PCR methods were able to detect the presence of biofouling hydroids in ambient water. However, despite exposure to suspended hydroid particle concentrations that did result in gill damage in some salmon, quantitative PCR results did not correlate with histological gill assessments. For opercular swabs to serve as a diagnostic tool for detecting biofouling-mediated gill damage in live salmon, increased specificity of genetic markers and improved sampling methods are needed. Animal trial permit no. 24252 (granted 06.07.2020, Norwegian Food Safety Authority). [ABSTRACT FROM AUTHOR]

Objective: The need to augment of Walleye Sander vitreus populations may increase as these populations face challenges of changing habitats and climatic conditions. Since little has been published outside of agency reports on wild broodstocks, the intent of this study was to describe sex‐specific Walleye spawning participation from a Great Plains broodstock operation. Specific objectives will assess standardization to collect target number of broodstock effort, catch per unit effort, and length and age participation of female and male broodstock. Methods: Walleye were collected at Sherman Reservoir, Nebraska, during April spawn collection operations from 2015 to 2019. Gill nets were used to collect female Walleye, and boat electrofishing was used to collect male Walleye. Catch per effort was calculated for each sex, fish were measured to nearest 1‐cm length‐group, and a dorsal spine was taken from a subset of fish per length‐group. Mean lengths and ages were calculated for each year of the study. Data were combined for all years of the project to display percent contribution by length and age. Result: The amount of effort to capture 100 female and male Walleye varied by 4× and 2.5×, respectively, over the 5 years of sampling. Mean lengths and ages (±SE) of female (65 ± 1 cm; 10.4 ± 0.1 years) and male (43 ± 1 cm; 6.3 ± 0.1 years) Walleye collected were consistent during this study. The female Walleye collected represented 14 different ages, but ages 9–12 comprised 66% of all captured broodstock. The collected male Walleye also demonstrated age‐compressed spawning tendencies, with ages 4–7 accounting for 74% of collected individuals that represented 13 different ages. Conclusion: These results can define the anticipated variability in catch that can be expected at broodstock collection operations along with connection to specific lengths and ages of Walleye. Additionally, recognition that female and male Walleye broodstock contributions are consistently coming from four specific ages that are not the same year‐classes may allow spawning operation staff to anticipate brood availability and ultimately improve the planning efficiency of these operations. Impact StatementWalleye populations throughout North America have declined, with many populations sustained through stocking efforts. Stockings often rely on a manager's ability to find and manage wild sustainable broodstock. Previous research efforts have focused on the collection of broodstock, egg‐take operations, and stocking products, with little research devoted to the population dynamics of the broodstock themselves. We provide this information for a Great Plains Walleye broodstock to provide a benchmark for managers and provide a template of how awareness of broodstock population characteristics can be integrated into the planning of these operations. [ABSTRACT FROM AUTHOR]

Length‐weight relationships are useful for stock assessments and modeling alternative conservation and management strategies for both native and non‐native fishes. We developed length‐weight relationships for 18 native and non‐native riverine fishes in the lower Red River catchment. Fishes were sampled in the summer and autumn seasons between May 2021 and March 2024 via electrofishing and gill nets. Measurements for each specimen consisted of total length (mm) and weight (g). We provide L‐W relationships for 14 native fishes consisting of 5 families (Lepisosteidae, Catostomidae, Ictaluridae, Sciaenidae, and Polyodontidae) and 4 non‐native species belonging to the family Cyprinidae. We collected 6,845 individuals ranging from 67 alligator gar to 1,848 smallmouth buffalo. All the L‐W relationships were significant (p < 0.05), and the majority (72% of species) of relationships between length and weight had r2 values > 0.70. Our findings provide insight into the L‐W relationships of riverine fishes and can be useful for modeling alternatives targeted at native fishes of recreational value and the removal efforts of non‐native fishes. [ABSTRACT FROM AUTHOR]

Gillnets are widely used in research and commercial fishery activities. As passive gear, gillnets can be selective and dependent on the diel migration of fish. In areas with limited littoral extent, inshore–offshore migration may cause bias in the gillnet catch. Our hypothesis was that some factors, such as gillnet saturation, fish depletion, or chemical cues, could be the cause of the bias. We used a total of 66 CEN gillnets deployed at Římov Reservoir parallel to the shore at different positions of littoral-pelagic gradient. Individual fish direction was recorded from inshore, offshore, or unknown direction (i.e., entangled fish). A total of 5791 fishes from nine different species were caught. For most fish, it was possible to determine their directivity, and most fish were captured in littoral or first pelagic gillnets. Shallower and deeper benthic gillnets differed in their bleak (Alburnus alburnus) catch. No significant differences were found between fish directions. At the species level, only asp (Leuciscus aspius) and ruffe (Gymnocephalus cernua) showed differences between the captured directions in one case. The results support the assumption that gillnet capture is a random process that to a great extent is connected to random local movements. This is good news for fish monitoring projects. Sampling catch is likely to reflect true changes in the fish community, and not the effects of the deployment of the sampling gear. The experiment also showed that fish directivity statistics can be used for investigation of fish behavior and gear performance. [ABSTRACT FROM AUTHOR]

The present study aimed to assess the stock of Chloroscombrus chrysurus in the Ivorian coastal waters to support its sustainable management. Approximately 2,520 specimens were collected between July 2022 and June 2023. The fish were captured using beach seines and gillnets, then measured and weighed to the nearest millimeter and gram, respectively. Stock assessment was conducted using the Fisat software, which analyzed pooled length-frequency data. The estimated growth parameters for Chloroscombrus chrysurus were as follows: asymptotic length (L∞) of 22.05cm, growth rate (K) of 0.82 year-1, growth performance index (Φ') of 2.59, theoretical age (t0) of -0.084 years, and life-span (Tmax) of 3.57 years. Instantaneous fishing mortality (F) was estimated at 0.81 year-1, while natural mortality (M) was 1.70 year-1. The exploitation rate (E) was 0.32. The length at first capture (Lo50) was 13.32cm, which is slightly lower than the length at first sexual maturity (13.42cm). The findings indicate that the Chloroscombrus chrysurus population in Côte d'Ivoire's coastal waters is at moderate risk of overexploitation. To mitigate this risk, it is crucial to monitor the fishery and to implement immediate measures, such as increasing the mesh size of the nets and the cod-end or bag of beach seines. [ABSTRACT FROM AUTHOR]

A new fishing technique has been introduced in Lake Kivu, across the Congo side. It consists of gillnets on which light‐emitting diode (LED) lamps are attached. Traditional fishermen have introduced the fishing technique without any studies related to the positive and drawback effects of this fishing technique. We sought to understand whether the gillnets with LED lamps fishing technique improve fishing catches and can be regarded as sustainable for the Lake Kivu ecosystem, or is it just only a marketing strategy for gillnets and LED lamp sellers. Two complementary approaches have been used in this study. Experimental fishing campaigns were conducted from June 2021 to June 2022 and monitoring of fishing team in the field coupled with surveys of fishermen about the effectiveness use of this new fishing technique. We observed that (i) 88% of fishermen using gillnet in the Bukavu sub‐basin have already adopted the recently introduced fishing technique; (ii) the average catch per unit effort of gillnets with LED lamps is higher than those without LED lamps (3.84 ± 1.95 kg/net vs. 2.69 ± 2.04 kg/net); (iii) these gillnets retrieve larger specimens (79.88 mm vs. 76.69 mm) and generate monthly a higher average profit to fishermen ($916.35) than the fishing technique lacking the LED ($807). However, (iv) the gillnets with LED lamps generates a lot of plastic trash: around 2130 kg of plastic bags/month under fishing conditions in the Bukavu sub‐basin. So, this new fishing technique is a real panacea for its practitioners, but a veritable Pandora's box generating plastic pollutants in Lake Kivu. Instead of banning this new fishing technique, we need to adapt it by using submersible LED lamps. [ABSTRACT FROM AUTHOR]

The present study documents the first occurrence of Siganus fuscescens, known as the mottled spine foot, within the inshore waters of Vaan Island (latitude 8°73 N, longitude 78°16 E) and New Fishing Harbor (latitude 8°84 N, longitude 78°22 E), which are located in the Gulf of Mannar region. The species, commonly referred to as rabbitfishes, was captured by bottom-set gill nets deployed in reefassociated areas of the Gulf of Mannar at a depth of approximately 2-3 m. Furthermore, detailed analyses of the morphometric and meristic characteristics of the specimens were conducted using established taxonomic keys. A comprehensive discussion is also presented, elucidating the distribution patterns of Siganus species within the Gulf of Mannar region. [ABSTRACT FROM AUTHOR]

The Xisha Islands constitute the largest coral reef archipelago on the northern margin of the Coral Triangle and are the largest coral reef archipelago among the islands in the South China Sea. This study employed various survey methods including underwater spearfishing, gill netting, handline fishing, longlining fishing, underwater visual surveys, and environmental DNA (eDNA). Additionally, historical data from 1956 to 2023 were reviewed to comprehensively analyze the adaptation characteristics of the fish community structure in the Xisha Islands. The Xisha Islands have documented a total of 874 coral reef fish species, categorized into 27 orders, 102 families, and 337 genera. Of these species, the order Perciformes demonstrated the greatest species richness, which represents 71.05% of the total fish species documented. The structure of coral reef fish communities in the Xisha Islands has undergone significant changes. Firstly, a significant decline in the population of large-sized and carnivorous fish species was observed. The proportion of large-sized fish species diminished by 6.02% (62 species), and the medium-sized fish species saw a reduction of 3.09% (51 species). In contrast, there was a surge of 9.12% in the small-sized fish species population. The carnivorous fish species experienced a decrease of 4.73% (102 species), while an increase was noted in the population of herbivorous and omnivorous fish species. Secondly, the numbers of orders, families, and genera have also significantly decreased, with noticeable declines in the average taxonomic distinctness (Delta +), the variation taxonomic distinctness (Lambda +), functional richness (FRic), and quadratic entropy (RaoQ). Thirdly, the similarity between fish species at different time periods is relatively low. Among different functional groups, large-sized and carnivorous fish species exhibit the lowest similarity, whereas herbivorous fish species exhibit the highest. The turnover of live coral fish species is also evident. Overall, the coral reef fish in the Xisha Islands are showing a trend towards herbivory, miniaturization, and a simplification in species composition and functionality. This study contributes to a better understanding and prediction of the adaptation trends in fish species composition in the Xisha Islands, which is crucial for ensuring the ecosystem services of coral reefs and for the conservation and restoration of ecosystems. [ABSTRACT FROM AUTHOR]

To determine sex and maturity stages accurately without any physical injury and stress, especially for sensitive and high‐value fish species, employing a noninvasive ultrasound imaging technique could be a desirable approach. The ultrasound imaging method as a powerful eco‐friendly tool was established to determine sex, gonad volume, gonadosomatic index (GSI), and reproductive stages in the Indian shad, hilsa (Tenualosa ilisha). About 30 hilsa (15 males and 15 females) of different maturity stages were collected from the river Ganga round the year using gill nets. The ultrasound sonography (USG) was then employed in hilsa to determine the computed GSI. The fresh gonad volume of hilsa was determined using a water displacement method to ascertain actual GSI values. There was no significant difference between the calculated, real, and actual GSIs (P > 0.05) in both males and females. The validation of the precise maturity stages of ultrasound images of the gonad by the histological architecture indicated that USG images of the hilsa gonad depicted exact stages of maturity in both sexes except for stages I and II in males. The sex of the fish was accurately ascertained using ovarian ultrasound scanning for all the specimens. The calculated USG‐based ovarian volume was positively correlated (R2 = 0.97) with the actual and real ovarian volumes. The noninvasive and reliable ultrasonography technique was found to be an accurate and valid tool to track gender and gonadal development and predict the spawning periodicity in hilsa. [ABSTRACT FROM AUTHOR]

This study compiled and remodelled length selectivity studies carried out on fish caught with gill nets and trammel nets in the inland fishery in Türkiye and evaluated them based on both the initial reproduction length and minimum landing size of species. The required data for the study were obtained through a literature review. 34 selectivity studies in total were identified, and 26 (76.5%) of them were carried out with gill net while the remaining 8 (23.5%) were conducted with trammel net. 24 of the studies were carried out according to SELECT (Share Each Length-class's Catch Total) and 10 of them according to Holt (1963). In conclusion, it was found that minimum conservation reference size (MCRS) values determined by the Ministry in the inland fishery in Türkiye were substantially greater than lengths at first maturity (LFMs) of species and that fishing gears used for fishing typically tended to fish mature individuals above MCRS. The major problem in terms of management is that different ideal mesh sizes are applied to different fish species that are in the same fishing place. Set nets with an ideal-mesh size for a species has a potential of catching individuals below LFM of other species in the same fishing grounds. It is thought that this problem can only be resolved with the Ecosystem Approach to Fisheries Management (EAFm). [ABSTRACT FROM AUTHOR]

On February 27, 2018, a female smoothback angelshark, Squatina oculata, was incidentally captured in a gill-net fishery off the Mudanya coast (southeastern Sea of Marmara). An opportunistic photographic record confirmed the emergence of S. oculata in the Sea of Marmara, where its status in the area is considered questionable because of its absence for many years in the region. The current opportunistic records are valuable data sources, which can provide complementary information to fill the knowledge gaps in the life histories of rare, rarely caught, or endangered sharks and rays. [ABSTRACT FROM AUTHOR]

This study analyzed the catch of the ponyfish (Leiognathus equulus) landed at Muara Kintap Fishing Port in South Kalimantan, Indonesia. Local fishermen used various gear types especially bottom trawls, beach seines, drift gillnets, and encircling gillnets within Indonesia's Fisheries Management Area (FMA) 712. While bottom trawls displayed the highest efficiency, peaking at 65,956kg, representing 98.26% of the annual total catch. Moreover, they also indicated potential overfishing, particularly in 2022. The ponyfish catches were dominated by individuals measuring between 130- 134mm and weighing 35- 39g. Length-weight relationship data revealed an isometric growth pattern (b = 2.98) for the ponyfish, suggesting good overall health (K = 1.68± 0.17). However, CPUE (Catch per Unit Effort) data from 2022 raised concerns. The peak CPUE of 89.13kg/ trip, alongside a substantial total catch of 67,122kg across 753.1 trips, significantly surpassed the catch-maximum sustainable yield (CMSY) of 28,748kg/ trip and the optimal effort (Fopt) of 882 trips/year. This suggests overfishing and a potential decline in the ponyfish stock by 2023, representing a substantial loss of USD 3,934. Monthly catch data for 2022 further supported this, highlighting a fishing season from August to October, peaking in October (16,376kg) and continuing into December. To ensure the sustainability of the ponyfish population and fish processing industry, the fishing port authority should prioritize addressing the impact of overfishing practices, particularly trawling. Furthermore, continuous monitoring efforts are crucial to establish data-driven fisheries management practices. [ABSTRACT FROM AUTHOR]

Large whale entanglements are considered a significant threat to populations on a global scale. In the Mexican Pacific and Baja California Peninsula (1996–2021) a total of 218 confirmed entangled whales, from which 99 (45.4%) whales were fully released (66 by the Mexican Whale Disentanglement Network, known as RABEN). Five whale species were reported in confirmed entanglements: humpback (Megaptera novaeangliae, n = 187), gray (Eschrichtius robustus, n = 19), sperm (Physeter macrocephalus, n = 5), Bryde's (Balaenoptera edeni, n = 4), and fin (Balaenoptera physalus, n = 3). Eight types of fishing gear were identified out of 209 different gear sets; gill nets were the most common (n = 101, 48.3%), followed by pots (n = 49, 23.4%). Entanglements were reported in sixteen locations, and Banderas Bay had the most entanglement reports (n = 81, 32.8%). Several entanglements were tracked across multiple locations (n = 7), involving two teams with the most successful releases (n = 5), proving the efficiency of the RABEN entanglement response network. This information can be used to better understand entanglement impacts on large whales in the North Pacific and particularly in Mexico, to work towards mitigation of a problem that affects both whales and fishermen. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigated how different fish species are distributed in the sea based on where they are relative to the oceanic current region and how deep the water is. Researchers collected fish samples over four seasons from May 2018 to March 2019 along the coasts of the East Sea in Korea. They used special commercial gill nets to catch the fish at different depths, ranging from shallow to deeper waters. Overall, they found 73 different fish species and collected over 6000 specimens. Depending on the oceanic current region, they found different fish species in each study site. For example, in one area called Ayajin, they mostly found fish like blackfin flounder (Glyptocephalus stelleri), Pacific cod (Gadus macrocephalus) and mailclad sculpin (Icelus cataphractus). In another area called Hupo, different fish species were more common, such as blackfin flounder, Sohachi flounder (Cleisthenes pinetorum), and flathead flounder (Hippoglossoides dubius). The researchers also noticed that the types of fish varied depending on how deep the water was. This study helps us understand how fish populations change in different parts of the sea based on the oceanic current region and at different depths. This study assessed variations in demersal fish assemblages with respect to the study site and water depth. Seasonal samplings from May 2018 to March 2019 were conducted along the northern (Ayajin, Goseong) and southern (Hupo, Uljin) sites of the East Sea off the Korean coast, using commercial gill nets. Samples were collected at depths of ~50, ~80, ~150 m across the study sites, with concurrent monitoring of water column structures. A total of 73 species and 6250 specimens were collected. Distinctive fish species compositions were observed according to the study site and depth. Although Glyptocephalus stelleri was the most abundant fish species in both Ayajin and Hupo, Gadus macrocephalus, Icelus cataphractus, and Alcichthys elongatus were most predominant in Ayajin, whereas Cleisthenes pinetorum, Hippoglossoides dubius, and Gymnocanthus herzensteini were more prevalent in Hupo. In terms of depth layer, in Ayajin, G. stelleri dominated in both intermediate and deeper layers, with Hemilepidotus gilberti, A. elongatus, Enophrys diceraus common in shallower depths. Conversely, in Hupo, G. stelleri, C. pinetorum, and A. nadeshnyi dominated across all depth layers, whereas Dasycottus setiger and G. herzensteini dominated in deeper and shallower depths, respectively. Significant influences of the study site and water depth on fish assemblage structures were observed due to variations in water temperature at the seasonal thermocline boundary. [ABSTRACT FROM AUTHOR]

Artisanal fishing is an important subsistence practice in freshwater habitats worldwide, but overexploitation threatens the conservation of several nontarget species including crocodylians. We investigated the effects of artisanal fishing on the distribution of a population of broad‐snouted caiman (Caiman latirostris) inhabiting the Tapacurá reservoir, within the highly altered and threatened Atlantic Forest biome.We conducted spotlight surveys to detect caimans and gillnets deployed in the reservoir from April 2015 to June 2022. We evaluated temporal differences in gillnet encounter rates and the relationship between caimans and gillnet distribution.Gillnet encounter rates remained consistent year‐round, while caiman encounter rates were highest near gillnets, especially in the river channel and in forested margins. Caimans are opportunistic predators attracted by tangled fish in gillnets and likely prefer habitats with increased fish abundance.Future research should continue monitoring the interaction between caimans and fishing and include local communities in conservation efforts. [ABSTRACT FROM AUTHOR]

Objective: In 2000, the Laguna Atascosa National Wildlife Refuge acquired the Bahia Grande (Texas) management unit, a space that had lain barren and arid for 70 years. A large cooperative partnership launched a restoration project to replenish the basin and recover its original tidal hydrology. In 2005, the construction of a pilot channel successfully restored water throughout the basin, and plans to eventually widen the channel were developed. Our study aims to evaluate an estuarine habitat restoration by assessing ecological drivers and the impacts on species diversity. Methods: We evaluated species richness, detection/occupancy rates, and species–habitat relationships, and we estimated the sampling effort required to achieve a given level of relative precision if relative abundance was used instead of occupancy to inform future sampling. Sampling gear included bag seines for juvenile life stages and gill nets for capturing subadult and adult life stages. For analysis, we used a Bayesian negative binomial linear mixed‐effects model to evaluate richness–habitat relationships and a hierarchical Bayesian multispecies model to evaluate individual species–habitat relationships, and we calculated the total number of fish captured and relative standard error by gear and sample year to produce a precise estimate of relative abundance. Result: Overall, 29 species were caught between 2018 and 2021. Salinity emerged as a clear driver in the Bahia Grande, as both species richness and individual‐level responses were negatively associated with high salinity values. We found that catch estimated as relative abundance had much variability, as is typical of most survey programs assuming constant detectability, and the number of net sets or seine hauls required to achieve a given level of relative precision varied considerably depending on the species, season, year, and gear type. The most collected species were found in the upper extremes of their salinity tolerances—potentially a unique adaptation to this hypersaline system. Conclusion: Baseline data suggest that for the channel widening to be successful, there must be a noticeable increase in suitable habitat characteristics throughout the basin. Impact statementHabitat restoration is a unique opportunity to assess changes in aquatic communities. We used hierarchical Bayesian models to describe prerestoration community relationships for one of the largest coastal restorations in Texas. This flexible framework can be applied to other complex habitat restorations. [ABSTRACT FROM AUTHOR]

Sexual size dimorphism (SSD) is a widespread phenomenon in the animal world resulting from differential selection on the sexes. The northern pike (Esox lucius) is a freshwater apex predatory fish species that exhibits female-biased SSD, but the degree to which SSD varies among populations and what variables might dictate variation in SSD in this species remain poorly understood. We sought to quantify the degree of variation in SSD among northern pike populations across a large portion of their North American range, as well as evaluate associations between the magnitude of SSD in northern pike populations with environmental variables and life history traits of populations. We quantified SSD in 102 populations of northern pike across the province of Ontario, Canada, using a standardized gillnetting database, and investigated the degree to which both environmental variables (cisco [Coregonus artedi] abundance as catch-per-unit-effort, lake surface area, and latitude) and northern pike life-history traits (early growth and mortality rates) explained variation in female-biased SSD using linear models. Female-biased SSD in mean weight of northern pike increased with increasing cisco abundance, and the difference in female and male mean age increased with increasing latitude. Furthermore, SSD was greater in populations with lower female mortality and early growth rates. These results indicate that slow-growing, long-lived populations of northern pike should exhibit greater female-biased SSD, and that these conditions may be facilitated by the availability of large, energy-dense prey and cooler temperatures at northern latitudes. [ABSTRACT FROM AUTHOR]

A study was conducted on the design and the operational details of fishing gears and craft operated from 54 fishing villages bordering the Pulicat lagoon, one of the important lagoons of India (lat. 13.5593° N, long. 80.2098° E). Information was collected from 320 respondents covering a minimum of 5-7 fishermen from each fishing village. The investigation revealed the existence of 26 types of traditional fishing gear belonging to 15 categories. The pattern of operation of fishing gears used by fishermen was as follows: stake nets (33%), drift gillnets (24%), set gill nets (19%), drive-in nets (14%), and other gears (<10%). Among the 26 types of fishing gears analyzed, 7 gears, viz., hand-lift net, crab fishing gear, lighted crab scoop net, prawn fishing gear, wooden cover pot, cradle trap, and mono line with multiple hooks, were found to be ecofriendly. Further, the multi-stick drag net was found to be a detrimental fishing gear as its operation leads to indiscriminate fishing with a high contribution of juveniles fishes with higher growth potential. The study revealed that the fishing pattern with traditional gears being practiced in the Pulicat lagoon might be continued without further introducing detrimental fishing gear such as gill nets or mini trawl that are operated adjacent to this lagoon in the sea to sustain the fishery of this lagoon. [ABSTRACT FROM AUTHOR]

The Garua bacha, Clupisoma garua, holds considerable commercial and nutritional significance as a fish species. This study investigates the relationships between GSI (gonadosomatic index) and eco-climatic conditions, and provides comprehensive insights into several facets of reproduction, such as size at first sexual maturity (Lm), spawning season, peak spawning period, and proposes sustainable management strategies for C. garua in the Ganges River, northwestern, Bangladesh. Since January to December 2017, 570 female individuals have been gathered from the Ganges River using cast nets, gill nets, and square lift nets on a monthly basis. The total length (TL) of the specimens varied from 3.90 to 26.30 cm. Lm was estimated as 14.30 cm based on the results of the TL vs. GSI, MGSI (modified gonadosomatic index), DI (Dobriyal index), 14.00 cm through TL-FL regressions, and 15.18 cm depending on Lmax for this species. Furthermore, the spawning period was observed from May to August, peaking in June and July, based on greater GSI, MGSI, and DI values. Throughout the peak spawning season, there was not a significant differ from a value of 100 in the relative weight (WR) of the female species. During the spawning season, a substantial association between temperature and GSI (p = 0.0038); rainfall and GSI (p = 0.0043); DO and GSI (p = 0.0043); pH and GSI (p = 0.0002); and alkalinity and GSI (p = 0.0001) was detected. Analyzing a 55-year data series (1964–2018), it became clear that an increase in average air temperature of 0.0289 °C and a decrease in rainfall of 2.988 mm per year might possibly delay the spawning season of this species. As a consequence, the results of this study provide crucial information for developing management strategies to safeguard C. garua populations in the Ganges River and its adjacent ecosystems. [ABSTRACT FROM AUTHOR]

Pterygoplichthys pardalis is an invasive fish species that grows rapidly in Lake Tempe, Kabupaten Wajo, and has disturbed the existence of native, endemic, and introduced fish. This study aimed to analyze the reproductive biology of this species in terms of population control. The research was conducted from January to April 2023 at Tempe Lake, Wajo Regency, South Sulawesi. Fish samples were caught using gill nets, cleaned, and stored in a coolbox for observation in the laboratory. Reproductive biology observations began with the separation of male and female fish, measuring the length and weight of each with a fish measuring board and analytical scales. Samples were dissected for maturity gonad and fecundity observations. Length-frequency distribution of male fish ranged from10.08- 41.58cm, while that of female fish ranged from 10.08- 35.28cm. The overall sex ratio between male and female fish was 1:1 (balanced), while the sex ratio between mature males and females (maturity stage IV) was 1:2 (polygamy). The growth pattern exhibited a negative allometric trend, with a long spawning season reaching its peak in March. The species is considered a partial spawner. The length at first maturity of gonads (Lm) for male and female fish were 28,99 and 25.98cm, respectively. Moreover, the fecundity ranged from 201- 5,050 eggs with an average of 1,762± 966 eggs. [ABSTRACT FROM AUTHOR]

Reproduction is among the most vital biological processes in the life cycle of any organism, such as fish. The biology of Oreochromis niloticus reproduction in Lake Nasser and Lake Nubia was studied using different mesh sizes of gill nets. A total of 480 Oreochromis niloticus were caught from Lake Nasser, Egypt, and 369 from Lake Nubia, Sudan, from January through December 2021. Sex ratio size at first maturity and maturity stages of O. niloticus were examined. In Nasser's Lake, the sex ratio of male to female was 1:1.02, whereas in Lake Nubia, it was 1:0.89. The first maturity length in Lake Nasser was 27.5cm for males and 27cm for females, while in Lake Nubia, it was 32cm for males and 26cm for females. The gonado somatic index indicated that the species breeds in Lake Nasser and Nubia during summer and spring, respectively. [ABSTRACT FROM AUTHOR]

River impoundment is usually accompanied with consequences of alteration in the hydrological system and change in the biodiversity composition of the ecosystem. This study investigated the impact of the dams built on Challawa (that is, Challawa George-Dam) and Kano (that is, Tiga Dam) on the fish biodiversity of the reservoir and below-dam sections of the two rivers. Fish sampling was done using long lines, Malian traps, cast and gill nets from stations on the reservoir and below-dam sections of the rivers. Ten fish species were identified from the reservoir and the below-dam sections of Challawa River belonging to nine families and four orders. Fish communities of the reservoir and below-dam sections of Kano River consisted of 28 species belonging to 12 families and 7 orders. Results of the Shannon diversity index (H' ) indicated that the two reservoirs have relatively higher fish species diversity measures (that is, Challawa=1.948 & Kano=2.294) than the below-dam parts (that is, Challawa=1.833 & Kano=2.247) of their respective rivers. Non-metric Multidimensional Scaling (NMDS) analysis produced two-dimensional maps with stress values of 0.0554 and 0.0537, an indication that the model provided good representation of the original data in reduced-dimensional space. The ordination map indicated wide dissimilarities between fish communities of the impounded and below-dam sections. Furthermore, a one-way analysis of similarity indicated significant difference (P=0.0001) and high dissimilarities (R=0.643) between fish communities in the two sections of Challawa River and also in Kano River (P=0.001, R=0.929). Analysis of Similarity Percentage indicated 74.45% of the dissmilarities between fish communities in the two sections were cummulatively contributed by four species in Challawa River and 72.18% by five species in Kano River. The distinct differences in fish abundance and richness between the two sections is ascribed to increased ecosytem productivity often associated with the inundated portion of dammed river. It is recommended that more water flow across the dams should be encouraged as a mitigating measure to boost basin sizes of the rivers at the below-dam sections. [ABSTRACT FROM AUTHOR]

Balasubramanian, A.; Meenakumari, B.; Pravin, P.; Boopendranath, M.R.; Rajani, M., and Erzini, K., 2024. Mesh and hook selectivity of larger carangid Caranx ignobilis (Forsskal, 1775), captured along the Kanyakumari coast of India. Journal of Coastal Research, 40(3), 554–562. Charlotte (North Carolina), ISSN 0749-0208. The larger carangid Caranx ignobilis is one of the key commercial fisheries operated by traditional fishermen on the Kanyakumari coast of Tamil Nadu, India, using larger meshed gillnet and drift hand lines. No selectivity study was conducted for this species in chosen study area; selectivity studies were conducted for C. ignobilis using different larger meshed gillnets having mesh sizes of 13.5, 14.0, 14.5 and 15.0 cm and hooks No. 5,6,7, and 8. Catch data obtained from gillnets and hooks were appropriated into various uninormal models (i.e. normal scale, normal location, log-normal, and gamma model) and a binormal model for finding the best fit that employs the share each length catch total (SELECT) methodology incorporated in Generalised Including Log-Linear N Estimation Technique (GILLNET) software. The estimated parameters of these models were evaluated using the statistical tools (i.e. model deviance, dispersion parameter, residual plots) to determine the best fit of the selectivity data. The binormal model under equal fishing power and fishing power proportional to hook size were found as best fit for the gillnet and hook selection data respectively. For all meshes and hooks tested, mesh size of 14.5 cm and hook No. 5 showed good catching efficiency capturing the respective modal length of fish 63.3 cm and 62.4 cm, which revealed that modal length of fish caught in the experimental mesh size is greater than the gears used by the traditional fishermen. Gillnet catch data appropriately converged into unimode in the selection curve, whereas the hook catch data appeared with bimode under the binormal model. Over dispersion was common phenomena in catch data obtained from gillnet and hooks because of the dispersed nature of population and the abundance of a larger size of fish in the study area. [ABSTRACT FROM AUTHOR]

Background: The estimated biodiversity indices showed spatial and temporal variations in the biodiversity of finfish and shellfish among the three stations of Ennore Creek, from September 2018 to August 2019 and from September 2022 to August 2023 at fortnightly intervals. Methods: A total of three sampling sites (S1, S2 and S3) were chosen in ennore creek for the present research. Occurrence data of finfish and shellfish species caught using gill nets were collected at the three selected sites of ennore creek. PRIMER v7 (Plymouth routines in multivariate ecological research), a statistical software tool created at the plymouth marine laboratory in the united kingdom (Clarke and Gorley, 2006) was used. Result: The findings showed that within the study area, there were more species, higher abundances, larger individuals and a higher percentage of least concern (77.6%), not evaluated (16.3%) and data deficient (6.1%). For every species of shellfish that has been documented, the IUCN classification is 100% not evaluated. But there are very few species of shellfish and finfish. Significant variations in fish abundance were found when the mean abundance of vulnerable, endangered and least concerned species for the assessed, unprotected areas were analysed. [ABSTRACT FROM AUTHOR]

The distinct origin and hydrological characteristics of reservoirs, shaped by fluctuating water levels and seasonal variations, play a crucial role in determining aquatic species assemblages across diverse limnological zones. This study aimed to analyze fish and crayfish assemblages in the nearshore area of a canyon-shaped Mediterranean reservoir, seeking to identify seasonal and spatial convergent patterns and infer the factors influencing them. Samplings were conducted at five stations along the longitudinal profile of the reservoir at depths around 7 m using gillnets and hoops nets. A seasonal pattern emerged regarding species abundance and biomass, with higher values recorded during the warmer period. Additionally, a spatial trend was observed, indicating higher species abundance in the middle part of the reservoir and lower abundance near the dam, particularly during the colder period. Water transparency, temperature, and the distance from the dam were identified as the most significant factors affecting species assemblages in terms of abundance and biomass. This research provides valuable insights into the intricate interplay between environmental factors, seasonal changes, and the assemblages of aquatic species in a Mediterranean reservoir, contributing to our understanding of its ecological dynamics. [ABSTRACT FROM AUTHOR]

Visual line‐transect surveys are widely used to estimate the abundance of cetacean populations; however, this method can be prohibitively expensive. Thus, a less expensive alternative method was investigated in the present study, i.e., whether temporal changes in the bycatch per unit effort (BPUE) of cetaceans could be used to index the changes in their abundance. Specifically, the relationship between the annual BPUE of two main bycatch fisheries and the relative abundance of common dolphins (Delphinus delphis) was examined in 2012, 2013, 2015, and 2017 when vessel‐based line‐transect surveys were conducted in the coastal region of the East Sea of Korea. The encounter rate (individuals/km) by study year was significantly correlated with the annual BPUE of set nets. An increase in the density (individuals/km2) of common dolphins, estimated according to a hazard‐rate key function by study year, was associated with an increase in the BPUE of set nets. These results suggest that the annual BPUE of common dolphins could be used to index the species' relative abundance. The BPUE of set nets, which are fixed in coastal regions, reflect the densities of common dolphins in the coastal regions better than that of gill nets used in coastal and offshore regions. [ABSTRACT FROM AUTHOR]

Gizzard shads are facing a continual decline in population, necessitating the implementation of selective gear design for effective resource management. This study aims to prevent the bycatch of young gizzard shads, a non-target fish species, and to derive mesh sizes appropriate for fishery management. Experimental fishing (n = 11) was conducted by manufacturing gillnet fishing gear with different mesh sizes (50.5, 55.1, 60.6, and 67.3 mm) in the coastal waters of the southern Gyeongsang Province. Two methods were employed to estimate the appropriate mesh size of the shad gillnet as follows: firstly, by analyzing the selectivity curve based on body length data; secondly, by developing a complex machine learning model considering biological and economic factors. Model 1 was constructed using mesh variables to classify the score groups. As a result of this study, the total length with a 0.5 gillnet selection ratio. which was estimated to be 179.3, 195.6, 215.1, and 238.9 mm for the 50.5, 55.1, 60.6, and 67.3 mm mesh sizes, respectively. In Model 1, a mesh size of 57.85 mm or less was determined as the most appropriate mesh size. Therefore, considering both biological and economic aspects, shad gillnets should have a mesh size in the 50.5 to 55.1 mm range. [ABSTRACT FROM AUTHOR]

This work describes the length–weight relationship (LWR) and various reproductive parameters of Sardinella melanura caught by artisanal fishers using gillnets along the coast of Phetchaburi. The LWRs were significant (p < 0.001) in female, male, and combined sexes, with corresponding LWR equations of W = 0.0077L3.0616 (r2 = 0.867), W = 0.0067L3.1055 (r2 = 0.890), and W = 0.0061L3.1473 (r2 = 0.893), respectively. Regression coefficients (b) indicated isometric growth in females and males, while in pooled samples, b showed positive allometric growth. The relative condition factors (Kn) (mean ± SE) were 1.02 ± 0.004 in females and 0.99 ± 0.004 in males, and reached a peak in September. The gonadosomatic index (GSI) reached a peak in September, and the breeding season was between August and October. The relative fecundity estimates (mean ± SE) were 2249.3 ± 80.8 eggs⋅cm–1 and 1037.7 ± 27.9 eggs⋅g–1. The relationship equations for fecundity–length and fecundity–weight were F = 2.6943 SL3.79 (r2 = 0.587) and F = 603.5 + 1012.9 W (r2 = 0.512), respectively. Examples are presented to show how the results of this study could help fishery managers develop appropriate conservation management strategies for this species in the Inner Gulf of Thailand. [ABSTRACT FROM AUTHOR]

Background: The level of diversity has a crucial role in the stability of the ecosystem. The higher the variety, the more stable an ecosystem, including agricultural land cultivated by farmers. Increasing of population affected the higher demanding of community towards their consumption activities. Especially, the natural resources that comes from local area such as Sukamaju District. Biodiversity of resources urgently needed to preserve the ecosystems meanwhile being the potential source to fulfilled nourishment of the people. This study aims to determine the diversity of peatland ecosystems by using a purposive sampling method in every selection of subject groups based on the characteristics or characteristics of a specific population. Methods: Field and Laboratory activities are needed in this research. Sample collection using several methods according to the targeted sample. Most of the sample using purposive sampling but also line intercept transect method. Fish sampling used a fishing gear called a gill net with a mesh size of 2-7 inches. The fish caught is placed in a labeled coolbox. Insect collection was running in the morning at 07.00-11.00 and in the afternoon at 3-5 pm (UTC+09:00). Sampling is held once a month for three months at predetermined coordinate points. Diversity was analyzed using Shannon-Wienner diversity, evenness index, dominance index and intensity on peatlands. Result: The results found seven orders and 30 families, with a total population of 1,231 individuals. The most dominant types of insects are the orders Coleoptera, Hemiptera and Lepidoptera. High diversity index (H'=3.021), high evenness index (E=0.86243) and low dominance index (D=0.3101). Fish community structure obtained diversity index (H') included in the medium category, for uniformity values in the high class and dominance index values in the low sort. The dominant fish species found were Channa striata, Anabas testudineus, Lates calcalifer, Mugil cephalus, Plotosus papuensis and Toxotes chataerus, while Oreochromis niloticus, Oreochromis mossambicus, Hexanematichthys sagor and Megalops cyprinoides. While the types of molluscs found to have the highest abundance were Pila ampullacea, Pomacea canaliculata and Pilsbryoconcha exilis. [ABSTRACT FROM AUTHOR]

This article explores the historical battle for fishing rights by Native Americans in Michigan. In the 1970s and 1980s, Native American tribes faced challenges to their treaty rights, particularly regarding their right to fish in their ancestral homelands. The use of gill nets became a symbol of their fight for fishing rights. The conflict between commercial and sport fishing, as well as economic motivations, contributed to the tension between Native Americans and the state. The article emphasizes the cultural significance of fishing rights to Native American communities and the broader context of Indigenous rights movements during this time. It discusses the legal battles and conflicts surrounding Native American fishing rights, including court cases, resistance, and advocacy efforts. The article also addresses the ongoing controversy over fishing rights, with a recent proposed consent decree facing opposition from sport anglers. [Extracted from the article]

Background: Since the late 1990s, bigheaded carps (largely silver carp [Hypophthalmichthys molitrix] but also bighead carp [H. nobilis]) have established throughout the lower Mississippi River basin. Using previously studied oxbow lakes in the lower White River basin, Arkansas, we compared current (2017, "post-carp" establishment) fish assemblages to historical (2002, "pre-carp" establishment) fish assemblages. Fish assemblages were comprehensively assessed using multiple gears, including boat electrofishing, mini-fyke nets, and experimental small-mesh gill nets. Results: T-tests suggested that fish assemblage indices of richness, diversity, evenness, and dominance were often greater (P < 0.05) during the post-carp period as reflected by boat electrofishing and experimental gill nets. However, all indices were generally similar (P > 0.05) between the pre-carp and post-carp period with fish assemblages depicted using mini-fyke nets. Nonmetric multidimensional scaling analyses indicated that fish assemblages differed structurally between pre-carp and post-carp periods. Assemblage differences were linked to both small and large abundance changes for more than 20 species. Abundances of gizzard shad (Dorosoma cepedianum), emerald shiner (Notropis atherinoides), pugnose minnow (Opsopoeodus emiliae), crappies (Pomoxis spp.), bluegill (Lepomis macrochirus), orangespotted sunfish (L. humilis), and yellow bass (Morone mississippiensis) declined between the pre-carp and post-carp periods. Conversely, abundances of weed shiner (N. texanus), pallid shiner (Hybopsis amnis), longear sunfish (L. megalotis), buffalofishes (Ictiobus spp.), and gars (Lepisosteus spp.) generally increased during the same period. Conclusions: Although not possible to conclude assemblage shifts were entirely related to bigheaded carps due to the absence of an appropriate reference system where carps did not establish, the wide establishment of these carps is one of the most pervasive changes to have occurred in the lower White River ecosystem during the past two decades. Thus, it is probable to conclude that post-carp establishment observations from this study were at least, in part, attributable to bigheaded carp establishment. Impacts of further range expansions by bigheaded carps in the White River and other lower Mississippi River sub-basins are unclear, though this study suggests probable effects on native fish assemblages, underscoring the need for further research and monitoring. [ABSTRACT FROM AUTHOR]

Studies on the production of Pimelodidae catfish in the Amazon are generally carried out in large fishing centers. However, the data referring to small-scale fisheries have gaps that can represent a risk to the activity. This study evaluated the volume produced and the revenue obtained from migratory catfish of the Pimelodidae family of commercial interest landed in Humaitá, Amazonas, Brazil, from May 2018 to April 2019. Daily monitoring was carried out with the Z-31 Fishermen's Colony through questionnaires to fishermen for each vessel docked. The total production was 6013.93 kg, with 1,689 fish counted and 13 species. A total of 186 landings by 122 fishermen in 24 fishing sites characterized as rivers, lakes, and "igarapés" were evaluated. The average selling price was R$5.57/kg, and the highest volumes were obtained from July to September, mainly with gillnets, where the "Surubim" Pseudoplatystoma punticfer had the highest volume and revenue. Low productivity was verified in most localities, characterizing the fishing as artisanal. The lack of adequate conditions for storing and transporting fish, the local hydrological variations, and the presence of hydroelectric plants on the Madeira River are major factors limiting the fishing expansion in southern Amazonas. [ABSTRACT FROM AUTHOR]

Length-weight relationships are presented for twelve fish species collected at 22 sampling points in the Heishui River, a priority tributary for fish conservation in the mainstream of the Baihetan Reservoir area, China. A combination of gill nets was used for sampling over a period between November 2018 and May 2021. The gill nets consisted of 12 nets per point with dimensions of 20 × 2 m (length and width), mesh size ranging from 20 to 80 mm, and soaking depth ranging from 40 to 160 cm. In addition, fixed gill nets were employed, with 10 nets per point having dimensions of 10 to 30 m in length and 1.5 to 2.5 m in width. The mesh size of these fixed gill nets was 10, 15, or 20 mm. This study presents the length-weight relationships of twelve species for the first time in the Heishui River Basin, including the new maximum body length of Pseudorasbora parva (Temminck and Schlegel, 1846). The slope (b) values for the assessed species ranged from 2.5 to 3.5. All the estimated relationships are highly significant (P < 0.05) with a high coefficient of determination R 2 ranging from 0.9574 to 0.9997. It is expected that the results obtained from this study will contribute to filling the knowledge gap in this area and also assist fisheries scientists in future assessment studies. [ABSTRACT FROM AUTHOR]

The present study evaluates stocks of Etroplus suratensis concerning length-weight relationships (LWRs), condition factor (K), and truss analysis from different habitats, viz., West Bengal (freshwater hatchery), Gujarat (brackish water grow-out pond), and Odisha (Chilika lagoon) in India. All the stocks were collected using gill nets with various mesh sizes of 20–50 mm and cast nets with mesh size of 15 mm from February 2021 to September 2021. The total length (L), weight (W), and digital pictures were taken for LWRs and principle component analysis (PCA). The total length (L) and total weight (W) were measured to the nearest 0.1 cm and 0.01 gm, respectively, followed by regression analysis. The values of parameters "b" in the LWRs equation were estimated within the range of 2.50–3.82 and intercept "a" values (0.235–0.779) and "K" (1.07–3.37), respectively, for all different habitats and ecosystems with significant correlation values ( R 2 ≥ 0.85). In truss morphometric analysis, principal component 1 (PC1) contributed the highest (93.1%) and principal component 2 (PC2) contributed 4.6% to the size and shape variation amongst the stocks from different habitats and ecosystems. The scatter plot analysis and canonical variate analysis (CVA) have shown that the Gujarat and West Bengal stocks are closely placed and separated from the Chilika-Odisha stock. Similar variations were also observed in the ANOSIM boxplot analysis, where Chilika-Odisha stock scored higher than the other two stocks. Since data available regarding LWRs and truss morphometry studies of E. suratensis from different habitats are limited, the present study will provide a clear insight into the differentiation of E. suratensis stocks from different habitats in India. The overall findings of the present study could be utilized for the conservation and sustainable management of E. suratensis. [ABSTRACT FROM AUTHOR]

Background: The present study of the length-weight relationship and condition factors of two Eutropiichthys vacha and Rita kuturnee, from Godavari River Andhra Pradesh, from the year August 2021 to July 2023 at fortnightly intervals. Methods: The log transformation formula was employed to establish length-weight relationships (LWRs) [3]. The length-weight equation used was W=aLb, in the usual notations. Linear regression of the log-transformed equation, log(W) = log(a) + b log(L), was utilized to calculate the parameters 'a' (intercept) and 'b' (slope) of the relationship. Result: A total of 1453 specimens of E. vacha and 1273 specimens of R. kuturnee were collected by using gill nets. The collected specimens exhibited a total length range of 10 to 27 cm for E. vacha and 7 to 18.5 cm for R. kuturnee. Correspondingly, the body weight range was recorded as 12 to 140 gm for E. vacha and 8 to 50 gm for R. kuturnee. Statistical analysis revealed a negative allometric growth trend for both males and females of E. vacha and R. kuturnee, with b values ranging from 2.569 to 2.711 for E. vacha and 2.53 to 2.61 for R. kuturnee. The fluctuation in the relative condition factor ranged from 1.06 to 1.09 for E. vacha and 1.001 to 1.12 for R. kuturnee. Furthermore, the overall health conditions of these two species were determined to be favorable. [ABSTRACT FROM AUTHOR]

Information on yellow perch Perca flavescens population dynamics and responses to various abiotic and biotic factors in oligotrophic, north‐temperate inland lakes is limited. Water level fluctuations are known to influence available habitat and biological communities within the littoral zones of lakes, yet research is lacking for yellow perch in Wisconsin. The goal of our study was to characterize yellow perch population‐level responses to natural water level fluctuations in four northern Wisconsin lakes using a 39‐year time series. On average, increasing water level periods correlated with lower mean fyke net and gill net relative abundances (catch‐per‐unit‐effort), though generally not statistically significant. Yellow perch mean relative weight varied among lakes and was significantly greater during increasing water level periods for all lakes except one. The lack of statistically significant findings potentially suggests a buffering mechanism of north‐temperate oligotrophic lakes due to their small surface area to volume ratios, relative lack of nutrients, and(or) littoral structural habitat compared to other systems (e.g., shallow eutrophic lakes). Our results suggest that natural water level fluctuations may not be an environmental concern for yellow perch populations in some north‐temperate oligotrophic inland lakes. [ABSTRACT FROM AUTHOR]

The idea of the article was to verify the thesis that acoustic studies of ichthyofauna in lakes provide sufficient information to determine the necessity (or lack thereof) of carrying out a full procedure for assessing the ecological status based on fish. The manuscript compares acoustic data collected in 2008 and 2021 in Lake Dejguny (Poland) as a result of acquisition carried out with the same EY-500 echosounder, on the same routes (transects), and the echogram analyses were carried out using software dedicated to this echosounder. Target strength (TS) distribution was determined in the lake and in individual water layers with a thickness of 2 m, as well as, using the mapping method, changes in the distribution of fish in selected water layers. Large changes in TS distribution in the vertical profile were demonstrated between both years of the study, as well as a clear reduction in the space available for fish in waters below 24 m in 2021, which was associated with a reduction in the concentration of dissolved oxygen below this depth to a value lower than 2.5 mg L−1. It was suggested that it could be possible to develop a simple index enabling the assessment of changes in fish structure, based, similarly to the Large Fish Index, on the ratio of the number of large fish to small fish. The obtained results confirmed that the proposed methods of acoustic data analysis can be the basis for the decision on the necessity (or lack thereof) of conducting an assessment using the Polish national LFI-EN method based on the results of one-off fishing with Nordic multimesh gillnets. [ABSTRACT FROM AUTHOR]

Objective: The present research was conducted on the existence and species diversity of fish in the Shuhada River, one of the Kokcha River tributaries situated in Badakhshan Province, Afghanistan. There has not been a previous study on fish species diversity; this is the first attempt to fill out this gap and identify the fish species of the river. Materials and Methods: Fish specimens were collected from three selected sites in the Shuhada River. The study was performed twice in each season of the year 2022, by using a variety of fishing nets, like gill nets with a length of 5 m and a height of 2 m, although with meshes ranging from 3 to 3 cm knot to knot and hooks. Two samples were taken from each site in each season. Results: Generally, 463 fish specimens were collected from the three selected zones. The Futtah was one of the selected zones that had the highest number of fish species (38.8%), followed by Yasich (34.04%), and the least number of fish species (28.07%) were collected from the Maidan zone. It found that Salmo trutta is the most abundant species at 52.9%, followed by Schizothorax curvifrons at 34.5% and Paracobitis longicauda at 12.5% was the least abundant species. During the cold seasons of autumn and winter, fish migrate down in the Kokcha River, and in spring and summer migrate to the upper zone in cold water. Conclusion: During the current study, three fish species, Salmo trutta, Schizothorax curvifrons, and Paracobitis longicauda, were documented in the study area. Fish hunting and flooding are the main harmful forces causing the reduction of fish diversity in the Shuhada River. [ABSTRACT FROM AUTHOR]

The Giant Sea Bass is an apex predator of southern California kelp forests that historically supported large commercial and recreational fisheries but whose population was drastically reduced due to overfishing. Although regulations have been in place to protect Giant Sea Bass for over 30 years, there is concern for continued allowance of their incidental take in commercial gill net fisheries. Through landing records, logbooks, and federal observer data, we examined the commercial take of Giant Sea Bass to determine the: magnitude, location, age, and disposition of catch; whether this take was incidental or targeted; and its impact on the current population. We found that Giant Sea Bass landings declined since gill netting was banned in state waters in 1994 and their overall landings decreased by 75% since becoming protected in 1981. Over time, a greater proportion of older fish was seen in the landings with an increase in mature individuals over 13 years of age since 2000. We found no evidence that commercial fishers are targeting Giant Sea Bass. On average, Giant Sea Bass were landed on 4.2% of gill net trips from 1994 to 2021. Additionally, over the past decade the majority of Giant Sea Bass landings came from only 15 permit holders, but this made up only ~2% of their total landings in pounds as these are the most active permittees, bringing in the highest landings of White Seabass or California Halibut. Assessing gill net observer data, we found the mortality of released Giant Sea Bass is high at 72%, although despite this level of mortality, multiple fishery independent sources indicate Giant Sea Bass populations are increasing, suggesting that current protection measures may be effective. Despite these findings, it is challenging to interpret the full impact of the commercial fishery on Giant Sea Bass as an accurate measure of total discards is unknown without consistent observer coverage. [ABSTRACT FROM AUTHOR]

Waterbodies are polluted by human activities or the increasing intensity of these activities, and this affects fish populations. The quality of the water fish inhabit directly impacts their growth and overall health. Length-weight relationships (LWRs) and relative condition factors (Kn) were estimated for three freshwater fish species from the Sutlej River of India from October 2020 to May 2022. A total of 232 fish specimens were caught with cast and gill nets in Gobindsagar Reservoir, Himachal Pradesh and Ropar Wetland, Punjab. Total length was strongly correlated with all the morphological characters (p < 0.001). The growth coefficients calculated (b) for Bangana dero, Cyprinus carpio, and Sperata seenghala were 2.858, 2.506, and 2.555, respectively, and indicated negative allometric growth. The correlation coefficients (r) indicated strong linear relationships between the weights and lengths of all three fish species. The outcomes of this study will help fisheries researchers, environmentalists, and scientists to develop future monitoring and conservation strategies for these fish species. [ABSTRACT FROM AUTHOR]