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Despite Batesian mimicry often eliciting predator avoidance, many Batesian mimics, such as some species of hoverfly (Syrphidae), are considered to have an "imperfect" resemblance to their model. One possible explanation for the persistence of apparently imperfect mimicry is that human perceptions of mimicry are different from those of natural predators. Natural predators of hoverflies have different visual and cognitive systems from humans, and they may encounter mimics in a different way. For example, whilst humans often encounter hoverflies at rest on vegetation, or in photographs or textbooks, where they are typically viewed from above, natural predators may approach hoverflies from the side or below. To test how viewing angle affects the perception of mimicry, images of mimetic hoverflies and their models (wasps and bees) were shown from different angles in an online survey. Participants were asked to distinguish between the images of models and mimics. The results show that the viewing angle does affect perceived mimicry in some species, although it does not provide a complete explanation for the persistence of imperfect mimicry in nature. The effect is also highly species-specific. This suggests that to understand better how selection has shaped mimetic accuracy in hoverflies and other taxa, further study is required of the viewing angles that predators utilize most commonly in nature. [ABSTRACT FROM AUTHOR]

Traditional methods for collecting robust samples of recreational effort and catch data from offsite mail or telephone surveys are becoming increasingly difficult to obtain. Smartphone applications (apps) that allow recreational fishers to report their effort and catch are a potentially viable data collection tool, but may be biased. We evaluated demographics, effort, and catch of freshwater anglers in south‐west Western Australia by comparing independent data from concurrent phone‐recall and app‐diary surveys for a 12‐month period in 2017–2018. Survey modes differed, with higher proportions of app respondents angling in freshwater and being avid anglers. For both survey modes, unweighted mean effort (days fished) was higher in dams than rivers, but was higher from the phone‐recall survey for dams and rivers. The unweighted distribution of kept and released catches (number of fish per angler) of rainbow trout (Oncorhynchus mykiss) and redfin (Perca fluviatilis) were similar between survey modes, with higher retention of redfin and higher release of rainbow trout. Kept and released rates of freshwater cobbler (Tandanus bostocki) and brown trout (Salmo trutta) were less common in both survey modes. Lower response rates and higher survey participation by avid anglers (≥20 days per year) from the app‐diary survey may bias survey data. Such bias needs to be addressed when using digital data collection methods, along with improving recruitment and retention of app participants. [ABSTRACT FROM AUTHOR]

Freshwater biodiversity is rapidly declining worldwide, especially in tropical island environments which appear to be particularly vulnerable to alien species. Monitoring biodiversity using effective methods is crucial for conservation efforts. This study aims to examine the capacity of the eDNA-based method to provide accurate measures of fish and crustacean biodiversity, and how it can be implemented in the French West Indies. To this end, we conducted eDNA and electric fishing capture-based surveys in parallel, both upstream and downstream, in nine Guadeloupean rivers and during two different seasons. While both methods were congruent in terms of species richness and composition, the eDNA-based method generally exhibited greater efficacy and reliability in assessing biodiversity. The exception to this trend was observed during the second campaign for the crustacean community. The quantitative data (the numbers of individuals and percentages of sequences) also proved to be uncorrelated for crustaceans during the second campaign, indicating that further knowledge of crustacean biology is needed. Nevertheless, the eDNA-based method was able to detect the presence of alien, rare and cryptic species, showing that it can be used in tropical island conditions for biodiversity assessment or conservation purposes. [ABSTRACT FROM AUTHOR]

Ongoing efforts to improve U.S. Caribbean fisheries management include increased consideration for human dimensions data and increased stakeholder input and engagement. Given the significant pressure that the local fisheries have sustained due to environmental degradation, climate change, storms and hurricanes, and overharvesting, combined with the critical data gaps that exist in both natural and human dimensions, it becomes particularly important to understand fishers' perceptions and aspects influencing them to promote efforts that will maximize the wellbeing of these social-ecological systems. In this study, data collected through surveys with fishers in the U.S. Virgin Islands were used to develop a correlation model to test relationships between variables using a heuristic model, the Anthropic Impact Assessment Model (AIAM) as the basis. Findings support the application of heuristic models, such as the AIAM, to develop hypotheses and test relationships to understand complex fishery social-ecological systems. The most significant findings with implications for decision making in the region include support for considering fishers' wellbeing as an indicator of ecosystem health and for using fishers' local ecological knowledge in the management process, particularly under data-poor conditions, for information that can be used to better target outreach and education efforts, as well as more effective recovery plans to promote resilience and adaptation to environmental change, including the impacts of natural disasters. Results of this study and future analyses using similar approaches can be used to guide the incorporation of human dimensions data into the decision-making process in the U.S. Caribbean and elsewhere. [ABSTRACT FROM AUTHOR]

This study used the Chub mackerel Scomber japonicus and Blue mackerel S. australasicus samples derived from both scientific survey and fishing vessels between 2020 and 2023, and analyzed the influence of species identification, different data sources and time variations on individual growth. The results revealed that the fattiness of samples from fishing vessels was slightly lower than that of scientific survey, and the body mass of samples from scientific survey grew faster. The length-body mass relationship showed that under the same fork length, the body mass of Blue mackerel was lighter than that of Chub mackerel. The range of condition factor was 1.886x10-6-6.721x10-5, with the exponent coefficient b mostly greater than 3. Heterogeneity analysis indicated that there were significant influence of data sources and years on the mackerels' growth, without significant growth difference between Chub mackerel and Blue mackerel in Northwest Pacific Ocean. Therefore, time-varying growth parameters and their uncertainties from different data sources of mackerels are strongly suggested to be considered during the stock assessment and fishery management which require life history traits. Additionally, species distinguishment between two mackerels could be given lower priority during data collection and management, but still deserve concern in the future research. [ABSTRACT FROM AUTHOR]

We comprehensively assessed marine recreational fishing of threatened guitarfishes (Pseudobatos percellens, Pseudobatos horkelii, and Zapteryx brevirostris) in Southern and Southeastern regions of Brazil. A dual‐method approach integrated social media reports and in‐person interviews to explore practices, challenges, and conservation implications of recreational fishing for these species. Seasonal capture of guitarfishes required the promotion of catch‐and‐release, especially during gestational periods, and the development of best angling practices manuals and accessible identification guides. With a focus on land‐based activities and engagement with fishers, our findings underscored the importance of collaboration among researchers, recreational fishers, and conservationists to map and monitor recreational capture and contribute to guitarfish research and conservation. [ABSTRACT FROM AUTHOR]

Observations of Black Spot Syndrome (BSS), a pigmented dermatopathy in marine fishes, have been increasingly reported in important grazers such as surgeonfish and parrotfish in the Caribbean. This condition has been linked to infection by the trematode parasite, Scaphanocephalus spp., although relatively little is known about the environmental drivers of infection and how they vary spatially. This study introduces a non-invasive, video-based method to survey BSS presence and severity in ocean surgeonfish (Acanthurus tractus). Application of the approach across 35 coastal sites in Curaçao was used to evaluate the influence of environmental factors on BSS, including longitude, herbivorous fish density, wave energy, depth, nutrient pollution, and inhabited surface area. Of the 5123 fish surveyed between February 2022 and January 2023, 70% exhibited visible signs of BSS, and the average number of lesions per fish increased by ~ fivefold from eastern to western sites along the leeward coastline. Within a site, estimates of BSS severity were broadly consistent between different divers, different reviewers of video footage, and the date of sampling, emphasizing the robustness of the surveillance approach. Analyses of environmental factors indicated that BSS decreased with wave intensity while increasing in association with higher nutrient runoff and fishing pressure. This study provides insight into environmental correlates of BSS severity while highlighting the use of video-based surveillance as a non-invasive survey method. The mechanisms linking environmental factors with BSS as well as its consequences for affected fish remain unknown, emphasizing the need for long-term and experimental studies in this system. [ABSTRACT FROM AUTHOR]

This study presents a survey of small-stream fish species from the Purus-Madeira interfluve, collected in four streams near Humaitá on the highway BR-319. The results reveal a rich and diversified ichthyofauna with 3016 collected individuals distributed in 84 species, six orders, 25 families, and 60 genera. Of all the specimens collected, the Characiformes was the most representative, with eight families, 26 genera, and 42 species, followed Siluriformes, with nine families, 20 genera, and 23 species. In terms of families, Characidae had the highest number of species (25), followed by Loricariidae (9), and Cichlidae (8). Among the 95 captured species's 11 are the first records for the region, evidencing a high diversity in these environments. Of the 84 species recorded in this study, 15 have not been assessed by the IUCN, while the remaining 62 include 23 listed as Least Concern (LC), three as data deficient (DD), and one as Near Threatened (NT). The southeastern Amazon region still has few fish surveys, especially in the region comprising the Purus-Madeira Interfluve, which highlights the importance of surveys to fill gaps and understand the biodiversity distribution patterns in the region. [ABSTRACT FROM AUTHOR]

The catch composition of a coastal gillnet fishery in the Eastern Mediterranean Sea was analyzed through a two-year experimental fishing survey. Seven fish species occurred regularly in the hauls. Surmullet, Mullus surmuletus, which is the most valuable demersal fish in Greek waters and the intended target of the gillnets in small-scale fisheries, was the most abundant and systematically caught species. Almost all surmullets were larger than their minimum conservation reference size. However, three commercially exploited species (Diplodus annularis, Pagellus acarne, and P. erythrinus) were caught systematically as undersized individuals. In addition, these three species were caught mostly as immature individuals. Moreover, the operational season of the surveyed métier overlapped completely with the reproductive period of five commercially exploited species (D. annularis, M. barbatus, M. surmuletus, Sphyraena sphyraena, and Trachurus trachurus). Improvements and the establishment of additional technical measurements should be considered for the small-scale gillnet fisheries in the studied area to attenuate their detrimental effects and achieve a better compromise between sustainable exploitation of the local multi-species fish resources and the need for an economically sustainable practice. [ABSTRACT FROM AUTHOR]

Dams and weirs impede the continuity of rivers and transit of migratory fish. To overcome this obstacle, fishways are installed worldwide; however, management after installation is important. The Miyanaka Intake Dam has three fish ladders with different flow velocities and discharges and has been under adaptive management since 2012. Fish catch surveys, conducted as an adaptive management strategy, place a heavy burden on fish. Furthermore, a large number of investigators must be mobilized during the 30-day investigation period. Thus, a monitoring method using environmental DNA that exerts no burden on fish and requires only a few surveyors (to obtain water samples) and an in-house analyst was devised; however, its implementation in a fishway away from the point of analysis and with limited flow space and its effective water sampling frequency have not been reported. Therefore, in 2019, we started a trial aiming to evaluate the methods and application conditions of environmental DNA surveys for the continuous and long-term monitoring of various fish fauna upstream and downstream of the Miyanaka Intake Dam. To evaluate the fish fauna, the results of an environmental DNA survey (metabarcoding method) for 2019 to 2022 were compared to those of a catch survey in the fishway from 2012 to 2022. The results confirmed the use of environmental DNA surveys in evaluating the contribution of fishways to biodiversity under certain conditions and introduced a novel method for sample collection. [ABSTRACT FROM AUTHOR]

Coastal rocky fish species support important fishing activities, but basic information is lacking for many before catches decline. Monitoring and management of coastal rocky fish species is urgently needed in Chile, but knowledge of these species is fragmentary at best. Performance of Baited Remote Underwater Video Stations (BRUVS) for assessing rocky fish assemblages was evaluated in south‐central Chile. Seven medium‐ to large‐sized exploited species dominated fish assemblages in the survey area, including five small cryptic rocky reef fishes, one agnathan and a catshark species. These seven species represented 78% of the species targeted by commercial fishing in the survey area. Furthermore, this tool provided new information on behaviour of rocky fish species. The simple, inexpensive and light nature of single‐camera BRUVS may be crucial for maintaining monitoring programs along remote areas of Chile. [ABSTRACT FROM AUTHOR]

Recreational fisheries represent a socially, ecologically, and economically significant component of global fisheries. The U.S. Inland Creel and Angler Survey Catalog (CreelCat) database includes inland recreational fisheries survey data across the United States to facilitate large‐scale analyses. However, because survey methods differ, a statistical method capable of integrating these surveys is necessary to assess patterns and relationships across regions. Here, we developed a hierarchical generalized linear mixed modeling approach to estimate the relationship between daily recreational fisheries catch and effort based on waterbody, socio‐economic, and ecological covariates. We applied this approach to CreelCat data on lentic waterbodies and found that recreational fisheries catch and effort were non‐linearly related (i.e., catch per unit of effort declined as effort increased), where effort varied regionally and by waterbody area, median county age, and distance to nearest primary road. This modeling approach could be used to inform data‐poor regions or waterbodies, make comparisons across spatial scales, and, with the inclusion of socio‐economic and ecological factors, inform management techniques in an era of shifting demographics and landscapes. [ABSTRACT FROM AUTHOR]

Objective: Crevalle Jack Caranx hippos are important coastal predators and support an increasingly popular catch‐and‐release sport fishery. However, population declines have recently been perceived by stakeholders in parts of the species' range. Here, we aimed to provide distribution and harvest trends for Crevalle Jack in the northwestern Gulf of Mexico. Methods: Long‐term fishery‐independent and fishery‐dependent data were collected by the Texas Parks and Wildlife Department from 1983 to 2021. Bag seine, bay trawl, and gill‐net samples were collected in conjunction with angler creel surveys. Crevalle Jack that were observed in fishery‐independent sampling were used to assess patterns in both juvenile and adult relative abundance, distribution, and seasonality. In addition, boosted regression tree models were used to highlight important predictors of Crevalle Jack presence. Crevalle Jack harvest observed during angler surveys was used to describe the fishery, including differences in inshore and offshore catch patterns. Relative abundance of both juveniles and adults was variable across years but displayed no trend throughout the time series. Result: Crevalle Jack of all sizes were found within inshore waters, with subadults and large adults particularly reliant on estuarine systems. Recruitment peaked in early summer, with juveniles occupying all major estuaries along the coast. Shifts in recruitment were evident in bag seines, as the mean date of catch trended almost 2 weeks earlier over the study period. The Crevalle Jack fishery was spread across inshore and offshore waters, with significantly larger fish harvested offshore during summer. The majority of anglers who harvested Crevalle Jack stated that they were specifically targeting other species, thus supporting the notion that the targeted fishery is mainly catch and release. Conclusion: As Crevalle Jack declines have been noted elsewhere in the species' range, these results could help to inform future management decisions in Texas. Impact statementCrevalle Jack are an important sport fish in the eastern Gulf of Mexico. However, anglers have noted population declines in parts of their range. Here, we examined seasonality, distribution, and recruitment of Crevalle Jack in Texas. Results indicate that populations are stable and provide important insights into Crevalle Jack ecology. While the fishery is largely catch and release, the reliance of large Crevalle Jacks on estuaries and nearshore waters could see them increase in popularity as an accessible sport fish. These findings will be important to inform future management decisions. [ABSTRACT FROM AUTHOR]

Traps (or pots) are one of the oldest and most widespread scientific survey gears for fish and decapod crustaceans around the world. Here, I review and synthesize the extensive scientific literature describing the various benefits and drawbacks of using traps as a survey gear in scientific studies. The widespread use of traps in fish and decapod surveys is due to several characteristics like their low cost, flexible design, ease of use, ability to fish unattended, and being amenable to pairing with other gears. However, there are a number of significant drawbacks of using traps, including highly variable catches due to environmental fluctuations or behavioral interactions or lost traps that continue catching and killing animals, that must be considered and accounted for when initiating trap surveys. This study highlights the types of habitats and species most and least suited for monitoring by traps, and emphasizes the importance of matching the goals and objectives of a trap survey with the correct trap design, mouth entrance, bait type, soak time, and pairing of gears. Pilot studies are also recommended before surveys are initiated to quantify the selectivity patterns of traps and identify the various factors that may influence trap catch. [ABSTRACT FROM AUTHOR]

Herein we report the first known collection of a larval Cryptobranchus a. alleganiensis (Eastern Hellbender) from Mississippi. We also document an extension of the known range of the species in Mississippi. Nearly all records of Eastern Hellbender in the state are from mainstem Bear Creek except for 1 collection in Pickwick Reservoir in 1981. However, we collected a larval Eastern Hellbender from Cripple Deer Creek, a tributary of Bear Creek, on 11 April 2023 while surveying for fish and crayfish. The individual was collected via kick sampling with a seine behind a half-submerged log. While habitat at the site of discovery did not seem typical of preferred Hellbender habitat, the streambed of Cripple Deer Creek at other locations may contain sandstone and limestone outcrops based on the surface geology of Mississippi. The collection of a wild-caught larval Hellbender is rare but encouraging for the conservation status of this species in Mississippi. Attempts in the last decade to detect Hellbenders in Bear Creek produced a single adult individual in 2015. To the authors' knowledge, no known studies have taken place within the inaccessible reaches of Cripple Deer Creek, and additional surveys are underway to assess if Cripple Deer Creek supports a reproducing population of Eastern Hellbenders. [ABSTRACT FROM AUTHOR]

Rodríguez-Rey and Whittaker (Hydrobiologia 850:2089–2100, 2023, https://doi.org/10.1007/s10750-023-05220-8) recently investigated the ecological niche of lumpfish (Cyclopterus lumpus) in the Atlantic Ocean using species distribution models. They utilise occurrence records of lumpfish from the Global Biodiversity Information Facility (GBIF) and environmental data extracted from Bio-ORACLE v2.0. A premise of their analysis is that that the GBIF data reflects the relative distribution of lumpfish in the North Atlantic. However, this assumption does not hold true, as evident from the geographic imbalance observed between the GBIF samples and the data obtained from commercial fisheries for lumpfish, as well as fish surveys conducted across the North Atlantic. There is also a concern that only 11% of the individuals listed in the dataset overlapped with the time period from when environmental parameters were estimated (2000–2014). Comparing the suitability index calculated using output from the species distribution models raises concerns about its reliability as it conflicts with the actual distribution of lumpfish from survey data in the eastern Atlantic. This conflict suggests serious problems with the model, and any projections into the future should be treated with caution. [ABSTRACT FROM AUTHOR]

The problem of calculating the normalized vegetation index (NDVI) from satellite data is considered. The index values calculated from the MODIS/Aqua radiometer data by the SeaDAS software package algorithm are compared with the values obtained at the La Crau research site (France) for 7 years. The site is located near the Mediterranean coast and is a flat field where grass grows. The measurements are carried out by the ROSAS automatic photometric station. Calculations show the proximity of satellite and field measurements: bias of 0.005 and standard deviation of 0.03. The algorithm used does not take into account the effect of aerosol on the NDVI value. However, the errors due to the lack of accounting for aerosol lie within the limits of the total calculation error. There is a slight dependence of the error on the zenith angle of the sun, which varied in the range from 20° to 70°. The bidirectional reflectance distribution function of the surface on the site is uniform, except for the directions close to the sunbeam. The measurements were far from the sunbeam zone. However, the accuracy of the calculation depends on the difference between the azimuth angle of the site survey and the azimuth to the sun. NDVI mismatches due to differences in the central wave numbers of different satellites also turned out to be significant. The comparison was made for the following radiometers: MODIS/Aqua, Landsat-8/OLI-1, Landsat-9/OLI-2, and Kanopus-V/MSS. [ABSTRACT FROM AUTHOR]

This study was designed as a brief survey of the marine community at Rincon Island, a human-made island off the coast of California that was constructed in 1957 for oil and gas production and processing. The purpose of the study was to inform the State of California about the ecological conditions at the island for decommissioning planning. The biota at the island had not been comprehensively surveyed since the 1970s. We conducted scuba belt-transect and photoquadrat surveys of the fishes, invertebrates and algal cover at Rincon Island and nearby natural reefs in the fall of 2020. Changes at the island have occurred over time; for example, we found a lack of red urchins, a paucity of sea star diversity, and an invasive bryozoan previously not observed at the island. However, many fauna and flora have persisted as dominant species for five decades. Our findings indicate that the island's complex armor revetment extending from the seafloor to above the splash zone and the varied wave exposure and currents around the installation provide a locally unique ecosystem that is significantly different from the small nearshore rocky reefs scattered in an area of predominately silt and sand. As found in many studies of other kinds of artificial habitats, the island supports a diversity of marine life greater than what would have been found in the area without its presence. [ABSTRACT FROM AUTHOR]

Blue sucker (Cycleptus elongatus) populations occur in the Mississippi River and Gulf of Mexico drainages of North America and are negatively affected by habitat fragmentation and flow regime alteration caused by dams. During fish assemblage surveys in August of 2022, we collected five juvenile blue suckers (312–428 mm total length) in the Angelina River upstream of Sam Rayburn Reservoir in East Texas (46,335 ha surface area) where the occurrence of the species was previously unconfirmed. Given this unexpected finding, we (1) analyzed mesohabitat associations to compare habitats we sampled with reports in the literature and (2) reviewed blue sucker occurrences in state, national, and global databases across historical (1950–1980) and contemporary (1981–2022) time periods to assess occurrence across gradients of habitat fragmentation and streamflow regulation. The blue sucker population in the Angelina River upstream of Sam Rayburn Reservoir was previously unconfirmed but is within the native range. Mesohabitats occupied by blue suckers were consistent with literature reports, including fast velocity, shallow depth, and coarse substrates. The low degree of regulation (19% of natural runoff stored by upstream reservoirs) and a high degree of habitat connectivity (287 rkm of unfragmented mainstem habitat) for the Angelina River upstream of Sam Rayburn Reservoir matched range‐wide patterns of persistence within relatively intact (unfragmented and unregulated) or remnant (fragmented but unregulated) riverscapes. Our review reveals that blue sucker populations might persist (1) in remnant river fragments where local habitat conditions are appropriate and (2) where effects of habitat fragmentation and flow regulation are not coupled. [ABSTRACT FROM AUTHOR]

We extend the modal decomposition method, previously applied to compress the information in the real-space bispectrum to the anisotropic redshift-space galaxy bispectrum. In the modal method approach, the bispectrum is expanded on a basis of smooth functions of triangles and their orientations, such that a set of modal expansion coefficients can capture the information in the bispectrum. We assume a reference survey and compute Fisher forecasts for the compressed modal bispectrum and two other basis decompositions of the redshift-space bispectrum in the literature, one based on (single) spherical harmonics and another based on tripolar spherical harmonics. In each case, we compare the forecasted constraints from the compressed statistic with forecasted constraints from the full uncompressed bispectrum which includes all triangles and orientations. Our main result is that all three compression methods achieve good recovery of the full information content of the bispectrum, but the modal decomposition approach achieves this the most efficiently: only 14 (42) modal expansion coefficients are necessary to obtain constraints that are within 10 (2) per cent of the full bispectrum result. The next most efficient decomposition is the one based on tripolar spherical harmonics, while the spherical harmonic multipoles are the least efficient. [ABSTRACT FROM AUTHOR]

The United States Inland Creel and Angler Survey Catalog (CreelCat) contains a national compilation of angler and creel survey data collected by natural resource management agencies across the United States (including Washington, D.C. and Puerto Rico). These surveys are used to help inform the management of recreational fisheries, by collecting information about anglers including what they are catching and harvesting, the amount of effort they expend, their angling preferences, and demographic information. As of May 1, 2023, CreelCat houses over 14,729 surveys from 33 states, Puerto Rico, and Washington, D.C., comprising 235 data fields across 8 tables. These tables contain 235,015 records of fish catch and harvest metrics, 27,250 angler preference metrics, 14,729 records of survey characteristics, 13,576 records of effort metrics, and 409 records of angler demographics. Though individual creel surveys are often deployed to meet local science and management objectives, creel data aggregated across jurisdictions has the potential to address larger scale research and management needs. [ABSTRACT FROM AUTHOR]

Nichols' common goby Rhinogobius cliffordpopei (Nichols, 1925) is a small-bodied benthic carnivorous fish, and native to central and southeast China. Due to the interregional commercial exchanges of aquaculture and aquatic trade, it has widely introduced numerous water bodies outside the original range in China, but has not been found in Tibet. During a fish survey in May 2022, we collected 22 individuals of R. cliffordpopei, including five juveniles, from four sites in the Yarlung Zangbo River in Tibet. This finding suggests that R. cliffordpopei has established wild populations in the Yarlung Zangbo. To protect the endemic species, government departments should strictly limit the release to reduce the potential risks of non-native species. [ABSTRACT FROM AUTHOR]

Population abundance is a critical metric in fisheries and conservation, but it is very difficult to measure accurately. Existing estimation methods present significant challenges: mark–recapture methods are time- and labour-intensive, and hydroacoustic echo counting methods face issues with target identity and the habitat types where they can be effectively applied. We present a new methodology for abundance estimation that can improve the reliability of echo counting methods. Split beam hydroacoustic survey data are integrated with telemetry data from fish bearing acoustic transponder tags. These tags are counted by a spatially and temporally concurrent multibeam acoustic survey to produce mark–recapture abundance estimates. We assessed this approach on four wild lake trout populations, ranging in abundance from ∼200 to ∼3000 adults. Our abundance estimates were consistent with those derived from conventional Schnabel and Jolly–Seber mark–recapture studies. We show that the precision achievable with this method in 1 year of field work rivals that provided by long-term (>10 years) continuous mark–recapture studies. We also discuss other ecological questions that could be addressed with this approach. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the characteristics of an attractive white female jaw angle in the three dimensions. An online survey of photographs of celebrities and laypeople was used to rate their attractiveness using 6 questions and a 3-item Likert scale. If ≥ 80% of participants rated a model as having attractive aesthetic features, it was considered attractive. The following features were considered important: a gonial angle in profile of 125.5° and in anterior view of 142°, an intergonial-interzygomatic width ratio of 0.83 and the vertical position of the jaw angles at the level of the stomion or upper lip. Surgeons can use these consensus criteria to help design a jaw angle implant, define orthognathic surgical strategies, or shape the angle using injectables. [ABSTRACT FROM AUTHOR]

Biodiversity conservation and management requires surveillance that captures the full spectrum of taxa. Here, we showcase the potential for a portfolio of visual, extractive, and molecular methods for detecting previously hidden components of tropical fish biodiversity in an economically and culturally valuable marine site that spans a tropical‐temperate ecotone—the Ningaloo Coast World Heritage Area. With scale and practicality in mind, we demonstrate how environmental DNA (eDNA) methods deployed in a stratified sampling design can yield a more comprehensive monitoring program for species presence than current alternatives (e.g., extractive sampling via anesthetic). eDNA from filtered water samples detected up to six times as many cryptobenthic fish species per site than samples collected with anesthetic, indicating it is a potentially powerful tool for assessing biodiversity of tropical fishes. However, there were also species that were only found when using anesthetic and the contribution of cryptobenthic species to overall diversity of the fish assemblage was unexpectedly low, suggesting not all cryptobenthic fish species have been detected with eDNA. There were also distinct differences in cryptobenthic assemblages both among sites and sample depths (2–3 m) when using eDNA from filtered water, suggesting this technique may be able to identify fine scale spatial differences in cryptobenthic fish assemblage. eDNA collected from water detects the most cryptobenthic species and is therefore an efficient tool for rapidly assessing biodiversity, but extractive techniques may still be required for biological and monitoring studies, and when combined with eDNA sampling provides the most comprehensive assessment of cryptobenthic fishes. [ABSTRACT FROM AUTHOR]

The surf zones are significantly affected by tides, however, several gaps still in knowledge of fish assemblages in surf zones response to spring‐neap and daily tidal cycles. We investigated fish assemblages in a surf zone of Gaolong Bay in China. The dynamics of fish assemblages were examined during the neap tide and the spring tide to test the hypotheses that (1) fish assemblages reflect a combination of species from around coastal habitats, and (2) dynamics of the fish assemblages were determined by both the spring‐neap cycles and diel rhythms of fish species. We collected 46 fish species comprising 16 coral reef‐seagrass species, 24 mangrove‐estuarine species, and 6 common coastal species. Fish abundance and richness were significantly higher during the neap tide than during the spring tide. Furthermore, during the neap tide, fish assemblages were mostly carnivorous coral reef‐seagrass species at night and were mostly omnivorous and planktivorous species during the daytime. However, no clear diel patterns were observed during the spring tide. We suggested that dynamics of the fish assemblages were mainly shaped by the diurnal rhythms of fish during the neap tide and by the tidal cycle during the spring tide. Our results support the notion that surveys of fish assemblages during the neap tide could collect more abundance and rich species of multiple ecotypes of fish to evaluate fish resource status in the around coastal habitats. Consequently, management approaches around surf zones with heterogeneous seascapes can lead to positive outcomes for inshore fish resources and ecosystem conservation. [ABSTRACT FROM AUTHOR]

Our knowledge of sawfishes remains scant for Latin America. Pristis pristis (largetooth sawfish) and Pristis pectinata (smalltooth sawfish) are critically endangered. In the Yucatán Peninsula (YP), P. pristis and P. pectinata inhabit coastal landscapes.A total of 290 surveys of fishers' local ecological knowledge (LEK), including a geospatial component, were collected; 74 literature sources and available archaeological data for the region were reviewed.Interdisciplinary results show the following: the common past presence of sawfishes, their cultural significance for coastal societies, and the contemporary absence of sawfishes in coastal areas where they existed historically; sightings of juveniles were only documented by elder fishers, and only two recent narratives mention sawfishes caught incidentally 5 years ago.Geospatial results provide evidence for 52 geographic sites where sawfishes were common in the YP.Results support the development of research methodologies to study human–nature interactions integrating LEK. This matters in the YP, where sociocultural values and landscapes have changed rapidly through increasing tourism development and human overcrowding.The results can help conservation managers understand the past presence and contemporary loss of sawfishes, and their habitat, and contribute to understanding the defaunation of megafauna in the YP through time. This is critical for tourism and fishery ecosystem services on which communities of the YP rely for their economies. [ABSTRACT FROM AUTHOR]

Objective: Since 2010, three spatially disjunct reef fish video surveys have provided fishery‐independent data critical to the assessment and management of reef fishes in the Gulf of Mexico. Although analytical approaches have recently been developed to integrate data from these surveys into a single measure of relative abundance and size composition, a more parsimonious approach would be to integrate survey efforts under a single Gulf‐wide survey design. Accordingly, we conducted a retrospective analysis of historical video‐ and habitat‐mapping data to develop a novel stratified random sampling design for conducting surveys of natural and artificial reef habitats. Methods: We conducted a series of classification and regression tree analyses to delineate both spatial and habitat strata, and conducted simulations to assess the performance of an optimized survey design. Result: Spatially, classification and regression tree results identified three depth strata (10–25 m, >25–50 m, >50–180 m) and three regional strata (north‐central Gulf, Big Bend, southwest Florida) in the eastern Gulf. For both natural and artificial reefs, habitat strata were delineated based on a combination of relative relief (low, medium, high) and size of the individual reef feature, although reef scale differed markedly between natural (<100 m2, 100–1000 m2, >1000 m2) and artificial habitats (<25 m2, 25–100 m2, >100 m2). To optimize effort among sampling strata, effort was allocated proportionally based on a combination of habitat availability and managed‐species richness for each stratum. Simulation results indicated that relative median biases were <10% and relative median absolute deviations <30% on estimates of abundance for most species examined on natural reefs under the optimal design, except Greater Amberjack Seriola dumerili. These measures of bias and imprecision were similar or higher for most species simulated using simple random and stratified random survey designs. Estimated relative median bias and relative median absolute deviations were notably higher for artificial reef surveys. Conclusion: Based on these results, survey efforts were integrated as the Gulf Fishery Independent Survey of Habitat and Ecosystem Resources (G‐FISHER) in 2020. Impact statementData from reef fish video surveys were analyzed to develop a new survey design in the Gulf of Mexico. The new design provides better estimates of reef fish abundance from natural and artificial reef habitats and will improve the assessment and management of multiple reef fishes. [ABSTRACT FROM AUTHOR]

The abundance of pike, a keystone top-predator, have declined dramatically in the Baltic Sea since the 1990s likely owing to recruitment failure. It has been proposed that wetland restoration can aid the recovery of the pike stock by increasing the number of recruits produced by anadromous populations. Yet, no previous studies have addressed whether wetland restorations are associated with higher abundances of adult pike in the coastal habitat. To address this, we performed standardised rod-and-reel survey fishing in paired bays with and without wetlands across three coastal areas and 3 years. To estimate dispersal and the contribution of wetland pike to the coastal stock, we tagged captured pike with passive integrated responders (PIT) and employed PIT reader stations in wetland inlets. The results showed that pike abundances were on average 90% higher in bays with an adjacent wetland although the effect varied among areas. Moreover, PIT-data uncovered that wetland pike constituted a high proportion of the pike found in adjacent coastal habitats and that some wetland fish dispersed up to 10 km. These results support that wetland restoration is a valuable tool to aid the coastal pike stock and ultimately restore the function and services of the coastal ecosystem. [ABSTRACT FROM AUTHOR]

The Mekong River is one of the most biodiverse, productive rivers in the world, supporting more than 1000 fish species and the livelihoods of tens of millions of people. The spatial dynamics and population status of many Mekong fish species, especially megafishes, are poorly understood. Therefore, this information is rarely incorporated into environmental risk assessments for large infrastructure projects, such as mainstream hydropower developments, which have been accelerating rapidly in the Mekong Basin. In this study, we present initial findings from the ongoing, collaborative, transnational acoustic telemetry monitoring of nearly 300 tagged fishes representing 27 species, which yield important insights into the potential impacts that proposed hydropower dams would have on populations of ecologically and economically important fish species. Included in these data are more than ten months of hydrophone records tracking the location of a 300 kg giant freshwater stingray, Urogymnus polylepis (Bleeker, 1852), currently the world's largest known freshwater fish, used to detect its migration behavior and distribution patterns. The telemetry data, combined with fisher surveys used to gather local ecological knowledge, provide evidence that the proposed dams would fragment the existing populations of this iconic species as well as those of other fish species that support river food web balance and local food systems. Furthermore, the existence of giant freshwater stringray populations and other unique megafauna reinforces the universal natural heritage value of the stretch of the Mekong River between the Lao People's Democratic Republic/Cambodia border and the city of Kratie. This stretch of river is located between two proposed megadams, the 900 MW Stung Treng Dam and the 2300 MW Sambor Dam. However, the Cambodian Ministry of Environment has also proposed this area for designation as a UNESCO World Heritage Site (Biosphere Reserve). The documentation of the movement of migratory fishes through this reach of the river using acoustic telemetry, the surprising discovery of the world's largest freshwater fish, the potential threat posed by dam construction, and the management ramifications of UNESCO World Heritage Site designation underscore the importance of scientific research and community involvement in landscape-scale development decisions. The decisions made today will affect the fate of this global biodiversity hotspot, the world's most productive inland fisheries, and the livelihoods of millions of people throughout the Lower Mekong Basin. [ABSTRACT FROM AUTHOR]

While both virulent and putatively avirulent Yersinia ruckeri strains exist in aquaculture environments, the relationship between the distribution of virulence-associated factors and de facto pathogenicity in fish remains poorly understood. Pan-genome analysis of 18 complete genomes, representing established virulent and putatively avirulent lineages of Y. ruckeri, revealed the presence of a number of accessory genetic determinants. Further investigation of 68 draft genome assemblies revealed that the distribution of certain putative virulence factors correlated well with virulence and host-specificity. The inverse-autotransporter invasin locus yrIlm was, however, the only gene present in all virulent strains, while absent in lineages regarded as avirulent. Strains known to be associated with significant mortalities in salmonid aquaculture display a combination of serotype O1-LPS and yrIlm, with the well-documented highly virulent lineages, represented by MLVA clonal complexes 1 and 2, displaying duplication of the yrIlm locus. Duplication of the yrIlm locus was further found to have evolved over time in clonal complex 1, where some modern, highly virulent isolates display up to three copies. [ABSTRACT FROM AUTHOR]

We present a hierarchical model for survey comparative fishing (CF) experiments (x) to utilize data from several species (s) and x to provide improved estimates of the relative efficiency of one survey protocol compared to another. This model is applied to four flatfish s and two x conducted by Fisheries and Oceans Canada (DFO) in 1995 and 1996. We used a monotone increasing function for relative efficiency, and included spatial effects to account for this important source of variation that was not considered in previous analyses of these data. We provide detailed analyses of the anticipated impacts of the various changes in the DFO survey protocols to better understand the reliability of the results. We show that there were important differences in relative efficiency among s, x , and spatial regions, which, combined with low sample sizes and low catch rates, contributed to poor precision in the estimates of relative efficiency. We conclude that stock assessment models in the future should have a goal of using unconverted survey indices, but also include information on the relative efficiency of trawl survey protocols as prior distributions. This will more adequately account for this important source of uncertainty. [ABSTRACT FROM AUTHOR]

Changes in species diversity can be an indicator of ecosystem disturbance, impairment, or recovery. Estimating sampling effort needed to adequately represent stream fish assemblages is necessary for informing conservation actions. Increased sampling intensity can increase species detection, affecting the accuracy and precision of biodiversity indices. Seining is commonly used in fish surveys in sand-bottomed streams of the western USA. Here, we sampled 20, 200-m long stream sites each with 40 consecutive seine hauls to determine how increased within-site effort affected measures of species diversity. An average of 10 seine hauls were required to collect 75% of species present at sites in 40 seine hauls, while 18 seine hauls were required to collect 100% of species observed at a site sampled with 40 hauls. Simpson's diversity index was highly variable when fewer than 7 seine hauls were performed at each site but stabilized when effort was > 15 seine hauls per site. Total dissimilarity and β-diversity components were variable under low sampling effort and also stabilized when effort reached 15 seine hauls per site. However, sampling with more than 18–20 seine hauls per site yielded few additional species. In shallow, sand-bed streams, we suggest sampling with < 5 seine hauls per 200 m of stream can result in unreliable estimates of α-diversity and variation in β-diversity. Increased effort of 15–20 seine hauls per 200 m of stream captured nearly all species present in 40 hauls per 200 m and stabilized species evenness and β-diversity indices. [ABSTRACT FROM AUTHOR]

Marine recreational fishing is popular in Norway, but current estimates of the catches by resident and tourist anglers are lacking due to several challenges, in particular Norway's long and intricate coastline with no defined access points and the large tourist fishery. To test methods for long-term monitoring of boat-based marine recreational anglers, estimate their catches, and characterize the fishery, we conducted a roving creel survey based on a novel spatial sampling frame and a survey of tourist fishing businesses in Troms and Hordaland County. These surveys showed that cod (Gadus morhua) and saithe (Pollachius virens) dominated the catches in Troms, while mackerel (Scomber scombrus) and saithe dominated the catches in Hordaland. The estimated total annual harvest of cod by all marine recreational anglers was 2 160 tonnes (relative standard error, or RSE 44%) in Troms and 73 tonnes (RSE 29%) in Hordaland, of which ∼40% (in weight) were landed in registered tourist fishing businesses, based on data from the tourist fishing survey. The results indicate that recreational anglers in Hordaland harvest more cod in coastal waters than commercial fishers. This study provides information for developing marine recreational fisheries monitoring in challenging survey situations to support science-based fisheries management. [ABSTRACT FROM AUTHOR]

The WALLABY pilot survey has been conducted using the Australian SKA Pathfinder (ASKAP). The integrated 21-cm H  i line spectra are formed in a very different manner compared to usual single-dish spectra Tully–Fisher measurements. It is thus extremely important to ensure that slight differences (e.g. biases due to missing flux) are quantified and understood in order to maximise the use of the large amount of data becoming available soon. This article is based on four fields for which the data are scientifically interesting by themselves. The pilot data discussed here consist of 614 galaxy spectra at a rest wavelength of 21 cm. Of these spectra, 472 are of high enough quality to be used to potentially derive distances using the Tully–Fisher relation. We further restrict the sample to the 251 galaxies whose inclination is sufficiently close to edge-on. For these, we derive Tully–Fisher distances using the deprojected WALLABY velocity widths combined with infrared (WISE W 1) magnitudes. The resulting Tully–Fisher distances for the Eridanus, Hydra, Norma, and NGC4636 clusters are 21.5, 53.5, 69.4, and 23.0 Mpc, respectively, with uncertainties of 5–10 per cent, which are better or equivalent to the ones obtained in studies using data obtained with giant single dish telescopes. The pilot survey data show the benefits of WALLABY over previous giant single-dish telescope surveys. WALLABY is expected to detect around half a million galaxies with a mean redshift of |$z = 0.05 (200\, \mathrm{Mpc})$|⁠. This study suggests that about 200 000 Tully–Fisher distances might result from the survey. [ABSTRACT FROM AUTHOR]

Fishers commonly disagree with stock assessment results, particularly when a stock declines and strict harvest controls become necessary. Such regulations alter fisher perceptions of stock dynamics, contributing to a divergence in perspectives. Some assessments have inconsistent terminal year values (retrospective patterns) which fuel distrust in scientific advice. When assessment and fishery perspectives disagree, independent surveys can help identify biases and interpret discrepancies. We examine fishery trends and assessment results for Atlantic cod in the Gulf of Maine, a stock which has declined for decades. Trends were compared to a scientific industry cooperative trawl survey and a telephone survey of fisher perceptions. Trawl survey results generally corroborate the assessment perspective on population scale and decline, yet suggest a different view of the age structure. Fisher perceptions were at odds with the assessment and trawl survey and likely resulted from regulations that altered fisher behavior, causing catch rates to increase while the stock declined. Divergent perspectives may be an unavoidable consequence of fishery management, yet acknowledging the underlying mechanisms might help avoid future conflict. [ABSTRACT FROM AUTHOR]

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We document that 3 human-infectious trematodes and their introduced first intermediate host snail (Melanoides tuberculata) are widespread throughout southern California. We surveyed 41 fishing localities, 19 of which harbored snails infected with zoonotic trematodes. Two of the parasites, Haplorchis pumilio and Centrocestus formosanus , are fishborne intestinal trematodes recognized as being important human pathogens in other areas of the world; the third, Philophthalmus gralli , can infect the human eye. An additional 5 species detected infecting M. tuberculata are likely of little direct threat to people; however, they may be recently introduced to the Americas, highlighting the risk that additional pathogenic trematodes transmitted by the snail in its native range could be introduced to the United States. The current, possible human-infection risk in California clarifies the need to consider the introduced snail and its parasites from a public health perspective anywhere in the United States the snail has been introduced. [ABSTRACT FROM AUTHOR]

In contrast to the rich collections of articulated spiny-rayed fishes from early Late Cretaceous and Eocene Lagerstätten, similar skeletal remains are sparse in Maastrichtian-Paleocene strata. Here we coin this poorly understood span "Patterson's Gap" and review known articulated skeletons from it, summarizing available information on their phylogenetic affinities, age, and environmental context. Roughly fifty percent of taxa in both the Maastrichtian and Paleocene come from Europe and North America, with percomorphs representing around 60% of the skeletal acanthomorph taxa in each interval. This is higher than the only pre-Maastrichtian assemblage with a reasonable sample of percomorphs, but lower than most Eocene and younger sites. Fossils from Patterson's Gap show a steady accumulation of the principal lineages of spiny-rayed fishes. Material from Paleocene or older strata provides evidence for most of the roughly 20 major acanthomorph divisions recovered by molecular studies. Many fossils from Patterson's Gap remain undescribed and unnamed, and almost none have been included within formal phylogenetic analyses. Revision of existing material, combined with additional fieldwork, should be a priority for future efforts seeking to clarify this murky but significant interval in the evolutionary history of a major vertebrate radiation. [ABSTRACT FROM AUTHOR]

Fishery-independent stock assessment surveys rely on consistent sampling methods, equipment and strategies to minimize variability in the data that could mask or confound trends in the assessed stock. Surveys typically use the same vessel and fishing gear each year as changes in either can affect the catchability of species during the survey, and therefore, the representativeness of the survey data. An unrecognized decline or increase in catchability could be interpreted as a decline or increase, respectively, in stock status. These observations could then lead to ill-informed advice to reduce or increase the level of harvest, respectively, producing hidden economic or conservation consequences. Factors that affect catchability, particularly during trawling surveys, are summarized here to help inform data considerations when there are changes in the vessel or gear used to conduct surveys. Data pertaining to the Greenland Halibut (Reinhardtius hippoglossoides) stock in the Northwest Atlantic Fisheries Organization (NAFO) Subareas 0+1 (offshore) (GH-0+1) are collected during several fishery-independent surveys, as well as through commercial logbooks and at-sea observer records. Fisheries and Oceans Canada (DFO) and the Greenland Institute of Natural Resources (GINR) use data from groundfish-focused surveys conducted in Divisions 0A-South and 1CD and a shrimp and fish focused survey in Divisions 1A to F to assess the status of the GH-0+1 stock. However, additional data are available from the Canadian Northern Shrimp Research Foundation survey and a few less frequent surveys conducted by DFO and the Greenland Institute of Natural Resources (GINR) in Divisions 0A-North, 0B and 1AB. This document summarizes the methods used for each survey, the types of data collected and the years and areas where surveys occurred, to provide an overview of data available for assessment and modelling of the GH-0+1 stock. [ABSTRACT FROM AUTHOR]

Issue addressed: Participants engaged in rock fishing are at risk of drowning. Following coronial investigation of fatalities, a 3‐year safety campaign targeting rock fishers was developed in Victoria, Australia. Key campaign messages were wearing lifejackets, not fishing alone, and checking sea and weather conditions. The reported study provides results from a campaign evaluation. Methods: Evaluation by self‐report and direct observation of safety attitudes and behaviours was undertaken pre‐ and during campaign. Data collections were as follows: (a) online survey of rock fishers recruited from panels, social media and rock fishing networks (n = 350) and (b) rock fisher direct observation and self‐report at selected Victorian rock fishing platforms (n = 282; n = 58, respectively). Results: Safety message recall was reported by 51.7% of rock fishers surveyed online though far fewer recalled campaign key messages. No effect on key safety behaviours or attitudes were detected for fishers on platforms during campaign. Never wearing a lifejacket was reported by 31.8% online, 60.3% at platforms and observed for 97.4%. From direct observation, most participants did not fish alone and checked conditions on arrival. Conclusion: Campaign evaluation measures showed mixed outcomes. Irrespective, most rock fishers carry high drowning risk through failure to wear lifejackets. Legal mandating of lifejackets for identified high‐risk platform is being introduced for Victoria, although careful evaluation is required to detect unanticipated outcomes. Informing future campaign evaluation, complementary methods highlight likely bias in self‐reporting through faulty recall or social desirability. So what?: Future campaigns require innovative or novel design, over longer duration, to capture attention and change rock fisher behaviours. [ABSTRACT FROM AUTHOR]

Although there is great fluctuation in annual recordings of jellyfish along the Moroccan Mediterranean coast and an absence of long-term datasets, there is a common perception that jellyfish numbers are rising. To better understand the possible economic losses sustained by Moroccan fisheries caused by the effects of jellyfish, we undertook a survey among fishers at the Atlantic port of Tangier and the Mediterranean port of M'diq. We focused on fishers' perceptions about jellyfish blooms in Moroccan waters and whether and how blooms affect their fishing activities. Our findings confirm that blooms have negatively affected fishing activities over the past decade in the Moroccan Mediterranean, but that the degree of impact varies considerably by fishery and location. Of the total respondents at M'diq, 86% reported that jellyfish reduced their seasonal revenue. The species mainly responsible for these losses were Pelagia noctiluca, followed by Rhizostoma pulmo and Chrysaora hysoscella. The annual direct damage caused by jellyfish has been estimated to be as high as US$3.26 million per year for the fleet at the port of M'diq. When jellyfish outbreaks occur, fishers must spend time repairing nets damaged by jellyfish, which adds more than 1 783 person-hours of work per year. [ABSTRACT FROM AUTHOR]

A preliminary ichthyofaunal and physico-chemical survey of estuaries on the east coast of South Africa from the Mpande Estuary to the Mtentwana Estuary was undertaken between November 1997 and January 1998. Sixteen estuaries were surveyed along this stretch of coastline and these were grouped into three estuary types: small (< 10 ha) predominantly closed estuaries, moderate to large (> 10 ha) predominantly closed estuaries and predominantly open estuaries. Multivariate analyses revealed significant differences between the three groups in terms of both their physico-chemical characteristics (small predominantly closed estuaries were different from predominantly open estuaries) and their fish communities (all three estuary types were significantly different). The estuaries in the study area fall within the subtropical/warm-temperate transitionzone and north of the subtropical/warm-temperate biogeographic break; tropical species dominated the fish communities of all the estuaries in terms of numbers of species and biomass. This survey represents one of the few fish surveys undertaken along this little-studied section of the coastline. [ABSTRACT FROM AUTHOR]

Simple Summary: An international survey was conducted regarding species used for research, methods of euthanasia, health monitoring, and biosecurity in fish laboratories. A total of 145 facilities from 23 countries contributed. Over 80 different species were reported to be used for research, of which zebrafish (Danio rerio) was the most common by far. Anesthetic overdose was the preferred method for euthanasia for adults, fry, and larvae not capable of independent feeding. For all developmental stages, the most popular anesthetic compound was tricaine. Around half of the respondents did not perform a completion method to ensure death. One-quarter of the responding facilities did not have a health monitoring system in place. Only a small fraction reported quarantine routines to ensure reliable biological barriers. There was little consensus amongst facilities in how to perform biosecurity measures. An international survey was conducted regarding species used for research, methods of euthanasia, health monitoring, and biosecurity in fish laboratories. A total of 145 facilities from 23 countries contributed. Collectively, over 80 different species (or groups of species) were reported to be used for research, of which zebrafish (Danio rerio) was the most common by far. About half of the participating laboratories used multiple species. Anesthetic overdose was the preferred method for euthanasia for adult, fry (capable of independent feeding), and larval (not capable of independent feeding) fish. For all developmental stages, the most popular anesthetic compound was tricaine (MS-222), a substance associated with distress and aversion in several species. Moreover, around half of the respondents did not perform a completion method to ensure death. One-quarter of the responding facilities did not have a health monitoring system in place. While most respondents had some form of quarantine process for imported fish, only a small fraction reported quarantine routines that ensure reliable biological barriers. Furthermore, less than one in five screened fish for pathogens while in quarantine. In sum, there was little consensus amongst facilities in how to perform biosecurity measures. Regarding euthanasia, health monitoring, and biosecurity processes, there is a need for updated and universal guidelines and for many laboratories to adjust their practices. [ABSTRACT FROM AUTHOR]

Developing Species Distribution Models (SDM) for marine exploited species is a major challenge in fisheries ecology. Classical modelling approaches typically rely on fish research survey data. They benefit from a standardized sampling design and a controlled catchability, but they usually occur once or twice a year and they may sample a relatively small number of spatial locations. Spatial monitoring of commercial data (based on logbooks crossed with Vessel Monitoring Systems) can provide an additional extensive data source to inform fish spatial distribution. We propose a spatial hierarchical framework integrating both data sources while accounting for preferential sampling (PS) of commercial data. From simulations, we demonstrate that PS should be accounted for in estimation when PS is actually strong. When commercial data far exceed scientific data, the later bring little information to spatial predictions in the areas sampled by commercial data, but bring information in areas with low fishing intensity and provide a validation dataset to assess the integrated model consistency. We applied the framework to three demersal species (hake, sole, and squids) in the Bay of Biscay that emphasize contrasted PS intensity and we demonstrate that the framework can account for several fleets with varying catchabilities and PS behaviours. [ABSTRACT FROM AUTHOR]

Fish classification (FC) is an expansively studied problem in the domains of image segmentation, pattern recognition, and information retrieval. It has been applied in a countless number of domains including target marketing. Meanwhile, governments are obliged to maintain the fish supply and balance between the ecosystem, commercial, agriculture field, marine scientists, and industrial arena of fish including the nutrition and canning factories. The various FC techniques performance is compared relying on the availability of preprocessing and feature extraction methods, the number of extracted features and classification accuracy, the number of fish families/species recognized. This survey also reviewed the use of Databases such as Fish4-Knowledge (F4K), knowledge database, and Global Information System (GIS) on Fishes and other FC databases. The study on preprocessing methods features extraction techniques and classifiers are gathered from recent works to enhance the understanding of the characteristics of preprocessing methods, features extraction techniques, and classifiers to guide future research directions and compensate for current research gaps. [ABSTRACT FROM AUTHOR]

Theory on access suggests there is a beneficial relationship between access to resources and well-being outcomes. Yet, the intricacies of the relationship between access and well-being have received limited empirical attention - especially in the context of fisheries. To examine this topic, we use a quantitative survey of 444 small-scale fishers in 8 countries in the Mediterranean Sea. We created composite scores from indicators related to fishers' perceptions of availability of resources, access capacities (financial, social, political, physical, human and cultural assets), access rights (formal rights and competing uses) and well-being. We then use descriptive analysis to characterize access and well-being among fishers and modeling approaches to examine how demographic factors are related to access rights and capacities and which factors are predictive of well-being. The research provides several insights. First, SSF had more positive perceptions of their access capacities and access rights than of resource availability. Second, SSF perceptions of resource availability, access rights and capacities varied significantly among sites and countries, but less so for demographic variables. Third, SSFs had a fairly positive perception of their overall well-being, however perceptions were less positive in some countries and for some indicators of well-being. Fourth, while some access capacities (i.e., social, cultural, political and financial assets) were positive predictors of an overall measure of 'human well-being', formal access rights were not a predictor of human well-being. These results highlight that managing SSF for well-being requires a nuanced understanding of and targeted approach to addressing access rights and capacities. • Theory suggests a beneficial relationship between resource access and well-being. • To examine this topic, we surveyed small-scale fishers (SSF) in the Mediterranean Sea. • Social, cultural, political and financial assets were positive predictors of well-being. • Formal access rights were not a predictor of human well-being for SSF. • Managing SSF for well-being requires a nuanced understanding of access. [ABSTRACT FROM AUTHOR]

Acoustic surveys of mixed fish aggregations often rely on manual allocation of acoustic energy to target species, with auxiliary information such as trawl catches and target strength distributions aiding interpretation. However, different teams of experts may use the same auxiliary data differently. In this experiment, seven teams of experts interpreted the same acoustic data, and we compared their classification to target categories to quantify uncertainty in the manual classification process. The teams largely agreed on the total acoustic energy attributable to organisms, but there was significant variation in how the teams split this energy on different target categories. This was caused by differences in applied thresholds for separating plankton and fish, as well as disagreements in species classification. For all target categories, the variation due to teams was lower than the overall variability across acoustic segments, but when scaled up to the number of segments in a typical survey, the team effect either dominated or was of similar magnitude as the segment variability. These results imply a need for further standardisation and uncertainty estimation of expert evaluations in acoustic surveys involving manual interpretation of echo sounder data. [ABSTRACT FROM AUTHOR]

This study investigated the effects of rainbow trout (Oncorhynchus mykiss) invasion on native fish communities in the upper Blyde River catchment. A fish survey was undertaken between September 2017 and October 2018 from 11 sites in the Blyde and Treur Rivers using electrofishing and fyke nets. Differences in species composition, relative abundance, and community structure among sites were tested using multivariate analysis. A total of ten fish species were captured. There were significant differences in composition and abundance between fish communities that could be attributed to O. mykiss invasion and variation in habitats. Populations of native species that historically occurred throughout the upper catchment, such as Enteromius treurensis, were greatly reduced and fragmented in the presence of O. mykiss. However, instream migration barriers such as waterfalls have prevented upstream migration of O. mykiss, and these invasion-free areas have remnant populations of native fishes that appear to be largely intact. This finding is consistent with other studies that have shown that introduced alien predatory fish can have a significant effect on fish communities and highlighted the need to prevent human-facilitated introductions in biodiversity sensitive areas, such as mountain headwater streams, that are inhabited by endemic and range-restricted minnows. [ABSTRACT FROM AUTHOR]

Automated acoustic recording systems deployed on commercial fishing vessels have been used since 1997 to document the distribution and relative abundance of Atlantic Herring from industry vessel surveys and fishing excursions in the Bay of Fundy and coastal Nova Scotia area within Northwest Atlantic Fisheries Organization (NAFO) divisions 4VWX. During the years 2015 to 2017, regularly scheduled surveys at approximately 14 day intervals were again conducted on the main Herring spawning components, and the spawning stock biomass for each component was estimated by summing these results. Six structured surveys were conducted in Scots Bay in 2015, six in 2016, and eight in 2017. Five usable structured surveys were conducted on German Bank in both 2015 and 2016. There were four (plus two) surveys on German Bank in 2017. The September 17 survey was initially excluded because it was nine days after the previous one; however, this resulted in a 28-day gap before the next acceptable survey. Subesquently, at the 2018 assessment meeting, this survey was included. One acceptable structured survey was completed in the Trinity Ledge area in 2015, followed by three in 2016 and four in 2017. There were no structured surveys conducted in 2015 or 2016 for Spectacle Buoy; however, three fall surveys were completed in 2017. In most cases, these surveys provided good coverage of the spawning areas consistent with established protocols. In 2015, the biomass estimate decreased to approximately 4% of the 2014 estimate for the combined survey areas of Scots Bay, Trinity Ledge, and German Bank (known as the Southwest Nova Scotia/Bay of Fundy [SWNS/BoF] [4X] stock). The 2016 estimate for the same overall areas decreased 29% of the 2015 estimate, while in 2017 the biomass increased (20%) above the 2016 estimate. The 2014 and 2015 estimates were above the long-term average since 1999, while the 2016 and 2017 biomass estimates are below the long-term average. These estimates provide mixed indications with regards to the SWNS/BoF stock. The German Bank spawning biomass estimate has decreased at an average annual rate of 9% since 2011. The Trinity Ledge 2017 spawning biomass has increased substantially to be above the long-term average; however, since 2006, the estimates have been well below the average. The recent large fluctuation in the SWNS/BoF spawning complex is occurring in the Scots Bay area; however, the long-term trend is upward. Biomass estimates from surveys of the coastal Nova Scotia spawning components for the Little Hope/Port Mouton, Halifax/Eastern Shore, and Glace Bay areas were also examined. Four (2013), six (2014), and six (2017) surveys were completed for Little Hope, as well as, four (2015), seven (2016), and 10 (2017) surveys for Halifax/Eastern Shore. No surveys were completed in the Glace Bay area. In Little Hope, a substantial increase in the spawning biomass estimate to a historic high was observed in 2015 (145,395 t), a three-fold increase over the 2014 estimate. There was a 57% decrease in the estimate in 2016 (61,408 t) followed by an 8% increase in 2017 to 66,815 t. The estimate is above the long-term average of 38,659 t. The total spawning biomass estimate for the Halifax/Eastern Shore area demonstrated a seven-fold increase from 9.586 t (2014) to 68,564 t (2015). While the biomass decreased to 54,352 t (2015) and 58,681 t (2017), it is above the recent five-year average of 39,602 t, and above the long-term average since 1998 (33,606 t). No survey was completed in Glace Bay during the 2015-2017 period. [ABSTRACT FROM AUTHOR]