Occurrence Of Fish Research Articles

Environmental Quality of Lake Mainit as a Habitat of Indigenous Goby, Glossogobius giuris (Hamilton, 1882) in Northeastern Mindanao, Philippinese

Changes in environmental quality of Lake Mainit could adversely affect the inhabiting organisms like the indigenous goby, Glossogobius giuris or pijanga. Hence, a thorough 16-month (i.e. December 2016 to March 2018) water quality study was undertaken, specifically on obtaining data for water temperature (OC), Dissolved Oxygen (ppm), pH, nitrate (NO3-N, ppm), ammonia (NH3-N, ppm), nitrite (NO2-N, ppm), phosphate (PO4-N, ppm) and light intensity (Lum/ft2) at the seven (7) established sampling stations within the Lake. Standard collection of water samples and their physico-chemical analyses were done and results were compared to DENR standards for freshwater water bodies. Results showed that the water quality of the Lake were still within the desirable range for Class A and Class C waters. This answered the underlying occurrence of fish kills to other factors and not on water quality changes. Highlight of this study is the notable increase of 0.9oC for surface and vertical temperatures of Lake Mainit over a decade and would show a glaring impact of global warming. Based on the 16 months monitoring, turnover occurred once in the Lake, particularly during northeast monsoon, indicating that Lake Mainit is a “monomictic Lake.”

SCUBA noise alters community structure and cooperation at Pederson’s cleaner shrimp cleaning stations

Recreational SCUBA diving is widespread and increasing on coral reefs worldwide. Standard open-circuit SCUBA equipment is inherently noisy and, by seeking out areas of high biodiversity, divers inadvertently expose reef communities to an intrusive source of anthropogenic noise. Currently, little is known about SCUBA noise as an acoustic stressor, and there is a general lack of empirical evidence on community-level impacts of anthropogenic noise on coral reefs. Here, we conducted a playback experiment on Caribbean reefs to investigate impacts of SCUBA noise on fish communities and interspecific cooperation at ecologically important cleaning stations of the Pederson’s cleaner shrimp Ancylomenes pedersoni. When exposed to SCUBA-noise playback, the total occurrence of fishes at the cleaning stations decreased by 7%, and the community and cleaning clientele compositions were significantly altered, with 27% and 25% of monitored species being affected, respectively. Compared with ambient-sound playback, SCUBA-noise playback resulted in clients having to wait 29% longer for cleaning initiation and receiving 43% less cleaning; however, cheating, signalling, posing and time spent cleaning were not affected by SCUBA-noise playback. Our study is the first to demonstrate experimentally that SCUBA noise can have at least some negative impacts on reef organisms, confirming it as an ecologically relevant pollutant. Moreover, by establishing acoustic disturbance as a likely mechanism for known impacts of diver presence on reef animals, we also identify a potential avenue for mitigation in these valuable ecosystems.

Community associations of birds with amphibians and fish in wetlands created for biodiversity

Conservation initiatives to support declining water-related biodiversity through wetland creation have increased during the last decades. Multiple studies have evaluated the suitability of created wetlands for birds and amphibians, but only a few have considered the species associations that might also affect the outcome. Using joint species distribution models, we explored species associations of birds, amphibians and fish in 52 created biodiversity wetlands in Sweden. As most of these wetlands were primarily created for increasing bird diversity, we asked whether the occurrence of fish and amphibians relates to bird species richness, pair abundance and chick abundance (as a measure of reproductive success) and whether conservation conflicts or synergies between birds, amphibians and fish can be observed. In general, we found positive bird-amphibian association patterns and negative bird-fish association patterns, although the uncertainties were high for these estimates. In line with previous research, the generally negative bird-fish co-variance indicates potential conservation conflicts between wetland creation for birds and fish, where fish might be introduced for recreational fishing or other ecosystem services. Therefore, our results suggest that it can be hard to benefit bird and fish communities with the same wetland, and separate wetland creation with different goals may be needed. The generally positive bird-amphibian species-species associations and the lack of previous studies revealing conflicts indicate synergies between wetland creation for birds and amphibians. However, research needs to further consolidate such synergies, including amphibian reproductive output from bird-rich wetlands.

Trends in Area of Occurrence and Biomass of Fish and Macroinvertebrates on the Northeast U.S. Shelf Ecosystem

AbstractClimate change can affect the habitat of marine species and hence their persistence and adaptation. Trends in area of occurrence and population biomass were examined for 177 fish and macroinvertebrates resident to the Northeast U.S. Continental Shelf ecosystem. Samples of these organisms were taken during a time series of research bottom trawl surveys conducted in the spring and autumn 1976–2019. The occurrence area of each taxon was modeled as the distribution of occurrence probability based on a random forest presence/absence classification model. Following, a population biomass of each taxon was modeled as a minimum swept area estimate, where the ecosystem was stratified biannually based on each taxon's spatial distribution. In both seasons, the sum of occurrence area and biomass across all modeled species increased over the study period. The summation of biomass is problematic since catchability is not known for most species; more importantly, most time series of individual species biomass trended higher. We found that the ratio of biomass to occurrence area, intended as a measure of productivity, showed no change in the autumn and had a weak increasing trend in spring. For the majority of taxa, the rate of change in biomass tracked changes in occurrence area (either positive or negative), but there were cases where the direction of change in biomass was opposite to the direction of change in occurrence area. Thermal conditions in surface waters appear to be a more important driver of occurrence area and biomass change than the change in thermal conditions near the bottom. These findings provide critical insights into the expected changes in ecosystem productivity transpiring with climate change.

The Freshwater Biodiversity Information System (FBIS) fish data: a georeferenced dataset of freshwater fishes occurring in South Africa

Freshwater fishes are recognised as South Africa’s most threatened species group. Reliable, long-term data on fish occurrence records are critical for effectively managing and conserving these species. A comprehensive freshwater fish dataset was compiled and uploaded to the Freshwater Biodiversity Information System (FBIS, freshwaterbiodiversity.org), comprising all available records of formally described freshwater fish species occurring in South Africa. An 18-month historic-data collation effort resulted in the accrual of 35 955 new records of freshwater fish from South Africa spanning 194 years (1828–2022), that have since been uploaded to the Global Biodiversity Information Facility (GBIF). Together with pre-existing GBIF records (24 861), a total of 60 837 freshwater fish records are thus now available for South Africa. The data show a marked decline in the number of native fish occurrence records over the last decade. Conversely, the number of occurrences for non-native fishes increased over the past three decades. A data breakdown is provided for each of South Africa’s nine provinces including total number of records, and the numbers of native, non-native, endemic and threatened species. These data provide a much-needed update of the known status and distribution of freshwater fishes in the country.

Investigation on Ichthyofaunal Assortment and Water Quality Parameters in the Ranganadi River of North-East India

Background: The north-eastern region of India well known its innumerable natural resources. Flanked by two of the biodiversity hotspots of Indian subcontinent, North-East India has rich biological diversity of flora and fauna in its every corner. The present study has undertaken to assess the ichthyofaunal resources and physico-chemical parameters of Ranganadi river which will contribute to the scientific knowledge domain and aid in the planning of much needed conservation strategies. Methods: The ichthyofauna and water quality parameters has been studied from February 2021 to January 2022 on a monthly basis in the three different terrains of Ranganadi river. Result: The study revealed 76 fish species belonging to 9 different orders and 26 families. The major share contributed by the order cypriniformes (47.36%) followed by siluriformes (23.68%), Perciformes (13.15%), Synbranchiformes (5.26%), Anabantiformes (3.94%), Clupeiformes (2.63%), Tetradontiformes (1.31%), Anguilliformes (1.31%) and Beloniformes (1.31%) constitutes total ichthyofaunal composition of Ranganadi river recorded in the survey. During the survey, occurrence of fishes from Endangered (EN), Vulnerable (VU), Near Threatened (NT) category also documented in the river basin. The water quality parameters were found to be in the suitable ranges in contrast to parameters of healthy aquatic bodies.

A sturgeon (Actinopterygii, Acipenseriformes) from the Upper Cretaceous of Africa

A single dorsal bony scute from the uppermost Cretaceous (Maastrichtian) marine phosphatites of central Morocco is identified as an acipenserid fish (sturgeon). The new specimen represents the first occurrence of an acipenseriform fish on the continent of Africa.

The influences of spatial-temporal variability and ecological drivers on microplastic in marine fish in Hong Kong

This study examined microplastic (MP) occurrence and abundance in marine fish collected from the western and eastern waters of Hong Kong during the wet and dry seasons. Over half (57.1%) of the fish had MP in their gastrointestinal (GI) tracts, with overall MP abundance ranging from not detected to 44.0 items per individual. Statistical analysis revealed significant spatial and temporal differences in MP occurrence, with fish from more polluted areas having a higher likelihood of MP ingestion. Additionally, fish collected in the west during the wet season had significantly higher MP abundance, likely due to influence from the Pearl River Estuary. Omnivorous fish had significantly higher MP counts than carnivorous fish, regardless of collection location or time. Body length and weight were not significant predictors of MP occurrence or abundance. Our study identified several ecological drivers that affect MP ingestion by fish, including spatial-temporal variation, feeding mode, and feeding range. These findings provide a foundation for future research to investigate the relative importance of these factors in governing MP ingestion by fish in different ecosystems and species.

Microplastic occurrence in fish species from the Iquitos region in Peru, western Amazonia

ABSTRACT The contamination of aquatic environments by microplastic has become a major threat to biodiversity. The presence of microplastic is documented in the aquatic fauna of the oceans, but, in the Amazon basin, reports on microplastic occurrence are few. The present study surveyed microplastic occurrence in fishes in an area of the Peruvian Amazon. We sampled 61 specimens of 15 commercial species from local markets in the city of Iquitos, Loreto Department. We detected a total of 2337 microplastic particles, 1096 in the gills and 1241 in the internal organs (esophagus, stomach, intestine, liver, gonads, pancreas, swim bladder and heart). The prevalence of microplastic particles was 100% and the overall average abundance was of 38.3 particles per individual (17.9 particles per individual in gills and 20.3 particles per individual in internal organs). Most particles were found in carnivorous fish. There was no correlation of particle abundance with fish standard length and weight. These results provided evidence of the degree of microplastic contamination of the fish fauna in the region of Iquitos.

NEOTROPICAL FRESHWATER FISHES: A dataset of occurrence and abundance of freshwater fishes in the Neotropics.

The Neotropical region hosts 4225 freshwater fish species, ranking first among the world's most diverse regions for freshwater fishes. Our NEOTROPICAL FRESHWATER FISHES data set is the first to produce a large-scale Neotropical freshwater fish inventory, covering the entire Neotropical region from Mexico and the Caribbean in the north to the southern limits in Argentina, Paraguay, Chile, and Uruguay. We compiled 185,787 distribution records, with unique georeferenced coordinates, for the 4225 species, represented by occurrence and abundance data. The number of species for the most numerous orders are as follows: Characiformes (1289), Siluriformes (1384), Cichliformes (354), Cyprinodontiformes (245), and Gymnotiformes (135). The most recorded species was the characid Astyanax fasciatus (4696 records). We registered 116,802 distribution records for native species, compared to 1802 distribution records for nonnative species. The main aim of the NEOTROPICAL FRESHWATER FISHES data set was to make these occurrence and abundance data accessible for international researchers to develop ecological and macroecological studies, from local to regional scales, with focal fish species, families, or orders. We anticipate that the NEOTROPICAL FRESHWATER FISHES data set will be valuable for studies on a wide range of ecological processes, such as trophic cascades, fishery pressure, the effects of habitat loss and fragmentation, and the impacts of species invasion and climate change. There are no copyright restrictions on the data, and please cite this data paper when using the data in publications.

Long term effects of smolt production strategy and early seawater phase rearing environment on mortality, growth, sexual maturation, and vertebra deformities in farmed Atlantic salmon (Salmo salar L.)

The life history of Atlantic salmon is plastic and determined by factors such as daylength and temperature. In aquaculture, artificial long days during smolt production maximize growth and allows for early sea-transfer, occurring between the first summer and autumn after hatching. However, the impact of such intensive rearing strategies on the salmon's welfare is not well understood. In this study, we follow underyearling (0+) juvenile salmon through two different smolt production regimes, either dietary induced seawater tolerance (fed with SuperSmolt®) under continuous light (LLS), or light-induced seawater tolerance, where for six weeks the photoperiod was lowered to 12 h light and 12 h darkness and then increased again to continuous light (LD-LL). Next, the LD-LL and LLS salmon were distributed into indoor seawater tanks where they experienced light and temperature conditions simulating either an August (AUG) or an October (OCT) sea transfer scenario lasting 2 months, after which all fish were transferred into a sea cage and reared there until reaching harvest size (10 months). Welfare parameters were mortality, growth, vertebra deformities (radiology), and sexual maturation. LLS grew faster than LD-LL smolts up until seawater transfer, while LD-LL post-smolts grew faster during the early seawater phase, resulting in equal harvest weights. The simulated AUG transfer gave higher harvest weights than the simulated OCT transfer regardless of smolt production strategy. Mortality during the first period in sea cages was higher in the LD-LL compared to LLS fish within the AUG scenario. At harvest, male sexual maturation was significantly higher in the LLS AUG (21%) group compared to the other groups (∼10%), while the occurrence of fish with vertebra deformities (1 ≥ deformed vertebrae) was highest among LD-LL fish within the AUG scenario (31%). Only the LD-LL fish had severely deformed individuals (fish with >10 deformed vertebrae): 2.8% in AUG and 5.6% in OCT. The present study shows that the incidence of male sexual maturation and vertebral deformities is lower in dietary- and photoperiod-induced smolts, respectively, by transferring them to seawater in autumn rather than summer. However, such a strategy could be expected to reduce the harvest weight of both LD-LL- and LLS-induced smolts.

Toxic metals and aflatoxins occurrence in smoked-dried fish and their health risks assessment

This study investigated the microbiological and toxic heavy metals contamination in smoked-dried fish, and evaluates their health risk implications. Fifteen widely consumed fish species were sampled randomly, and their aflatoxins, mercury “Hg,” cadmium “Cd” and lead “Pb” concentrations were evaluated though standard guidelines. The results revealed that fish flesh Hg level ranged from 0.085–0.258 mg/kg, Cd concentration ranged from 0.092–0.204 mg/kg, and Pb level varied from 0.173–0.329 mg/kg; the mean toxic metals level in the freshwater fish tissue was lower, when compared to the levels in the saltwater fish (seafood). Regarding toxic metal toxicity, the average Hg, Cd and Pb estimated daily intake values for children and adult were 0.1200 and 1.63 × 10−5 mg/kg bw/day, 2.13 × 10−4 and 7.57 × 10−5 mg/kg bw/day, and 2.48 × 10−4 and 1.24 × 10−4 mg/kg bw/day respectively. Likewise, children targeted hazard quotients (THQ) values were Hg (0.585), Cd (0.151) and Pb (0.071), while adult THQ values were Hg (0.293), Cd (0.076) and Pb (0.035). Children and adult hazard index (HI) values were 0.949 and 0.404 respectively; while Carcinogenic Risk (CR) values indicated that Cd had higher chances of cancer risks when compared to Pb. Additionally, the aflatoxins level in the fish species ranged from 0.564–9.422 ppb, with the seafood having lower aflatoxins level when compared to the freshwater fish species. Aflatoxins estimated daily intakes (EDI) exposure was 4.81 × 10−3 and 2.41 × 10−3 μg/kg bw/day for the children and adults respectively; while the aflatoxins HI value for children was 7.300 × 10−4, and for adults was 7.293 × 10−4. Health risks assessment of heavy metal accumulation in the fish, for both children and adults portrayed insignificant adverse health effects (THQ < 1), through the oral consumption of the fishes. Aflatoxins level detected in the all fishes was within acceptable limits (10 ppb) as approved by the World Health Organization; however, some of the values for freshwater fishes were above the allowable limit (2 ppb) approved by the European Union. Though, the results depicted a very low risk of toxic metals and aflatoxins poisoning, there is the need for proper evaluation of current fish processing and storage methods to prevent human exposure to toxic metals and aflatoxins introduced through smoked-dried fish consumption.

Determination of benzothiazoles, benzotriazoles and benzenesulfonamides in seafood using quick, easy, cheap, effective, rugged and safe extraction followed by gas chromatography - tandem mass spectrometry: Method development and risk assessment

The common use of benzothiazoles, benzotriazoles and benzenesulfonamides has led to widespread ubiquity in several environmental matrices. Their occurrence in edible fish could represent an additional exposure route for the population. The present study aims to develop a method for the simultaneous determination of these three compound families in seafood samples. Based on QuEChERS extraction, different salt combinations and clean-up strategies have been evaluated to achieve the highest recoveries while reducing the matrix effect in low and high lipidic content species. The best results were obtained with the original method salts and the lipid-selective push-through clean-up, which combined with gas chromatography-tandem mass spectrometry led to recoveries between 50 and 112% with negligible matrix effects and method detection limits between 0.15–9.50 ng g−1 dw. The application of the method to commercially available samples confirmed the presence of BTs as well as BSAs, with the latter being determined in seafood for the first time. Exposure and risk assessment calculations indicated a minor risk for the population when consuming fish.

Hydraulic gradient and wave height control the success of estuary artificial entrance openings

Intermittently Open/Closed Estuaries (IOCEs) are dynamic, sensitive estuaries that periodically close as a function of competing marine and fluvial energies. Once closed, IOCEs are often artificially opened to relieve localised flooding. Artificial openings are generally effective as a short-term flood mitigation strategy, however, sometimes IOCEs can close immediately after excavation without draining the lagoon. In this situation, the opening does not achieve its management purpose and reimplementation is required – costing many thousands of dollars at a time and leading to adverse impacts on estuary biota. Using a dataset of 137 openings at 37 IOCEs globally, we show that the hydraulic gradient (or grade) at opening and offshore significant wave height determine whether an estuary will remain open and drain its lagoon. The hydraulic gradient represents the energy slope between the estuary and the ocean, and wave height determines the capacity of waves to infill the channel with sediment to counter offshore erosion. Artificial openings are only successful when IOCEs are opened with a hydraulic gradient steeper than 0.017 m/m (equivalent to a grade of 1:60) and when significant wave height is below 4.30 m. These findings highlight that the estuary water level alone is not a good predictor of opening success, despite it being widely used to decide when to implement artificial openings. Using near-continuous monitoring of geomorphic change at 28 artificial openings, we show that the hydraulic gradient (and grade) at the time of opening controls the rate of channel expansion, outflow velocity at the mouth, lagoon drainage rate, and the time to reach peak channel width and outflow velocities. The tidal stage at opening can be used to either speed up or slow down the rates of change, potentially reducing the occurrence of fish kills associated with rapid drainage. Although the decision to open an estuary is a complex balance between environmental, cultural, socio-economic, and practical factors, we present a simple and cost-effective way to predict if artificial openings will be successful. The thresholds of our study can be used to complement existing decision support tools, but as a standalone method, are best suited for emergency openings where draining the lagoon to reduce flooding is the main management priority.

Use of multibeam imaging sonar for observation of marine mammals and fish on a marine renewable energy site.

Environmental data is crucial for planning, permitting, execution and post construction monitoring of marine renewable energy projects. In harsh conditions in which marine renewable energy is harvested, integrated monitoring platforms comprising multibeam imaging sonar systems coupled with other sensors can provide multiparametric data of the marine environment surrounding marine renewable energy installations. The aim of this study was to test the possibilities of observing the occurrence of fish and marine mammals using a multibeam imaging sonar system deployed at a wave power test site. The results obtained from a ten-day data set proved the platform as suitable for long time underwater monitoring and also revealed that the occurrence of fish and marine mammals was distributed across characteristic time and space domains. Large fish [>0.4 m] frequently occurred at night-time and near the benthic zone. Small fish [<0.2 m] frequently occurred during daylight and within the pelagic zone. The occurrence of seals was periodically distributed along a daily cycle, with intervals of 1-2 hours between maxima and minima. In conclusion, the use of multibeam imaging sonar can be a reliable technique for the qualitative and quantitative observations of fish and marine mammals in general and at marine renewable energy sites specifically, including protected and economically important species.

First record of potential epiphyte grazing species in commercial seaweeds (Kappaphycus spp.), Philippines

Commercial seaweeds (Kappaphycus spp.) being widely cultivated at sea face inevitable challenges such as ice-ice disease and epiphyte infestations. Hence, this research provided the first record of potential epiphyte grazing species associated with cultivated seaweeds. A total of 26 seaweed farms were surveyed for 7 months, from April to October 2022, to record the occurrence and abundance of blenny fish. Results from the visual census survey showed a total of 984 sightings of blenny fish (Petroscirtes spp.). The highest occurrence of blennies was recorded in planted seaweeds (81.4%), followed by ropes (12.3%) and floats/buoys (6.3%). Blennies are found to spend the majority of their time resting, swimming, and grazing on the algal epiphytes that are attached to seaweeds. These tiny fish, which are associated with cultivated seaweeds but are overlooked in seaweed farms, are critically important and can contribute little pressure to controlling epiphytes.

Food Composition and Feeding Intensity of Channa Striata from Selected Stations of River Krishna, Andhra Pradesh

Aim of the current piece of work was to study the food composition and feeding intensity of Channa striata from Krishna river from June, 2019 to July 2020. The gut contents were analysed from the three stations to undertaken the food composition of the fish. The major components of food items in the gut of fish was: fishes and their larvae, crustaceans, insect larvae, annelids with semi digested material and unidentified items. Fishes are identified as of teleost, particularly carps and cat fish larvae but most of the fishes leftovers could not be recognized since they are found in advanced phases of digestion with only scales &amp; skeleton remains. Gastropods are identified as polycheate larvae, and Crustaceans are prawn and crab larvae. The percentage occurrence of fishes and their larvae in gut contents and also feeding intensity were indicated that C. striata preferential food was fishes followed by crustaceans.

Spatial and temporal genetic stock composition of river herring bycatch in southern New England Atlantic herring and mackerel fisheries

Anadromous river herring (alewife and blueback herring) persist at historically low abundances and are caught as bycatch in commercial fisheries, potentially preventing recovery despite conservation efforts. We used newly established single-nucleotide polymorphism genetic baselines for alewife and blueback herring to define fine-scale reporting groups for each species. We then determined the occurrence of fish from these reporting groups in bycatch samples from a Northwest Atlantic fishery over four years. Within sampled bycatch events, the highest proportions of alewife were from the Block Island (34%) and Long Island Sound (22%) reporting groups, while for blueback herring the highest proportions were from the Mid-Atlantic (47%) and Northern New England (24%) reporting groups. We then quantified stock-specific mortality in a focal geographic area (∼3500 km2, including Block Island Sound) of high bycatch incidence and sampling effort, where the most accurate estimates of mortality could be made. During this period, we estimate that bycatch took about 4.6 million alewife and 1.2 million blueback herring, highlighting the need to reduce bycatch mortality for the most depleted river herring stocks.

Scale‐dependence of fish habitat associations in a North American river system

Abstract Determining the appropriate measurement scale to assess habitat variables is critical for ecologists assessing biological or ecological conditions. Depth, velocity, substrate, woody debris and other fish cover variables occur on both reach and microhabitat scales, and fish habitat associations with these variables may be scale‐dependent. The aim of this work was to better understand the importance of scale for fish–habitat associations with these variables in a framework consistent with environmental filtering and to test the hypothesis that habitat variable importance is scale‐dependent. I used prepositioned areal electrofishing in wadeable streams of the Delaware River basin to evaluate the associations of fish with the same variables summarised on different reach and microhabitat scales. The importance of scale for fish–habitat associations was assessed using two approaches that approximate an environmental filtering framework: variance partitioning with (1) ordination and (2) generalised linear mixed models. Variables on both the reach and microhabitat scales explained a significant fraction of the total variation in fish community composition (p &lt; 0.05). Variation decomposition of reach‐ and microhabitat‐scale effects revealed 20.2% and 2.0% of all variation were due uniquely to reach and microhabitat scales, respectively. Measures of coarseness, embeddedness, amount of riffle and areal coverage of five fish cover variables were significant explanatory variables of community composition at the reach scale only (p &lt; 0.05). Velocity and mesohabitat (amount or presence of riffle) were the only two habitat features that were significant explanatory variables of fish community composition at both the reach and microhabitat scales (p &lt; 0.05). Individual models of species occurrence revealed similar patterns as seen with analyses of community composition. For many fishes, habitat features quantified at the reach scale were more explanatory than at the microhabitat scale. Longnose dace (Rhinichthys cataractae) were more dependent upon microhabitat variables than reach‐scale variables, relative to other fishes. Mean velocity at the reach scale was the most important explanatory variable for explaining fish community composition and indicated support for the concept of environmental filtering at the reach and microhabitat scales. Few studies of fish occurrence have incorporated a study design and analytical framework that approximates the hierarchical nature of habitat. This study identifies important scales and predictors, demonstrates the importance of a multiscale approach, and provides support for the environmental filtering concept at the reach and microhabitat scales. These findings will allow ecologists to better account for scale‐dependent habitat associations and justify the use of fish habitat associations on reach and microhabitat scales for assessing biotic integrity, restoration and conservation of fishes.

Low functional vulnerability of fish assemblages to coral loss in Southwestern Atlantic marginal reefs

Marginal reefs sustain coral assemblages under conditions considered suboptimal for most corals, resulting in low coral abundance. These reefs are inhabited by numerous fishes with a generally unknown degree of association with corals that might lead to the assumption that corals play minor roles in determining fish occurrence, when corals could be actually sustaining diverse and resilient assemblages. Using site-occupancy models fitted to data of 113 reef fish species of different life stages (adults and juveniles) from 36 reefs distributed across the Southwestern Atlantic (0.87–27.6°S) we first assessed fish assemblage’s response to coral and turf algal cover, and identified coral-associated fish. Then, we simulated the loss of coral-associated fishes and contrasted it with random losses, providing inferences on the resilience of fish assemblage’s functional trait space to species loss. The entire fish assemblage responded more positively to coral than to turf algae, with 42 (37%) species being identified as coral-associated fish. The simulated loss of coral-associated fish reduced up to 5% the functional trait space and was not different from the random loss. These results reveal that marginal reefs of Southwestern Atlantic reefs host resilient fish assemblages that might preserve fundamental ecological functions and ecosystem services even with coral declines.