Papers by Jean-Christophe Joyeux
MARINE ECOLOGY PROGRESS SERIES, 2023
Herbivorous fishes can be sensitive to environmental fluctuations, which influence both availabil... more Herbivorous fishes can be sensitive to environmental fluctuations, which influence both availability of food resources and metabolic rate, and thus nutritional requirements. Impacts on herbivore nutritional ecology may result from seasonal variations in temperature and meteoceanographic shifts such as wind-induced upwelling events. We evaluated the effects of seasonal changes on the nutritional ecology of 3 nominally herbivorous fishes (Acanthurus chirurgus, Sparisoma axillare and Kyphosus vaigiensis) in a subtropical rocky reef on the southeastern Brazilian coast using a combination of gut content analysis (at 2 scales of magnification) and stable isotope analysis. Sampling of in situ water temperature covered both patterns of seasonal variation in sea surface temperature, and seasonal occurrence of upwelling. Local upwelling occurred throughout the year but less frequently in winter. Diet and isotopic niche displayed little seasonal variation. Species-specific patterns of seasonal variation indicated distinct responses to environmental fluctuations. Temperature alone cannot explain the locality-specific variation in the nutritional ecology of herbivorous reef fish, and contrary to predictions that digestion in herbivorous fishes is impaired by cooler temperatures, no significant shifts in species’ nutritional ecology were detected.
Regional Studies in Marine Science, 2023
The present study investigates the spatial and temporal patterns of species richness and assembla... more The present study investigates the spatial and temporal patterns of species richness and assemblage structure of decapod and stomatopod crustaceans in the area impacted by the Fundão dam collapse (Rio Doce basin, Brazil) in November 2015. From October 2018 to September 2019, monthly bottomtrawl samples were collected in estuarine and marine waters of the Rio Doce (directly impacted area) and three other localities. Forty-one crustacean species were recorded, with the overall community structure dominated by six species. The seabob shrimp Xiphopenaeus kroyeri was the most common species, with the coastal marine area near to the Rio Doce mouth being an important fishery ground. Species composition changed significantly among localities, habitats, and seasons, with marine and estuarine assemblages shaped by freshwater discharge. Distribution patterns of species were significantly influenced by the environmental variables potentially altered by tailings, such as turbidity and pH. Species richness and abundance differed among localities; as expected, they were generally higher on the inner shelf than in estuaries and higher during the dry season than the rainy season. Due to the lack of information before the disaster, the low number of species found in the Rio Doce estuary cannot be solely attributed to the disaster but also its freshwater condition. This is the first broad study of the estuarine and coastal marine decapod and stomatopod crustaceans in the region, and we suggest the need for long-term monitoring considering that the effects of this disaster are not easy to detect and probably need multi-year study to be evidenced.
Spinger, 2023
Intertidal ecology has been considered the cradle of modern marine ecology with insightful invest... more Intertidal ecology has been considered the cradle of modern marine ecology with insightful investigations on the biological and ecological mechanisms allowing “life between the tides”. Most of the early investigations focused on macrophytes (seagrasses and macroalgae) and benthic invertebrates inhabiting emerged intertidal substrata. However, tidepools also shelter a rich fauna, including fishes, which display a wide diversity and a variety of ecological interactions and functions. Here, we review the diversity, ecology, evolution and conservation of the American tidepool fshes, from defnition to trophic roles, ecological vulnerabilities and societal importance that reveal an extraordinary biodiversity and the important roles fshes play in the coastal ecosystems. Tidepool fsh studies increased sharply from the mid twentieth century onwards, but many geographic gaps still exist. Tidepool fishes connect marine and terrestrial communities via substantial predation upon insects and exporting energy to land as prey for terrestrial fauna. Sea-level rise driven by climate change will reduce or eliminate current intertidal habitats, where little or no space is available for landward accommodation in the supralittoral zone. Concurrently, tidepool habitat would be ‘squeezed’ to a narrow intertidal stripe by ‘coastal squeeze’ process. Endemic, habitat-restricted, and specialist species could be particularly afected by human-induced habitat loss on the coastal stripe. Tidepool fshes provide many ecological services, such as well-being, environmental awareness, outdoor recreation, and bioinspiration for ancient and current societies. The level of intertidal rocky shore protection varies among American countries, but in most cases rocky shores are included in the least efective protection categories allowing extractive activities.
Coral Reefs, 2024
Deposits of seabird guano on marine shores
have drawn the attention of companies and naturalists ... more Deposits of seabird guano on marine shores
have drawn the attention of companies and naturalists for
centuries. Among notable efects, allochthonous energy/
matter inputs by seabirds are responsible for shifts in
ecosystem functioning next to colonies. Here, we used
stable isotopes of nitrogen-15 (ratios of 15N: 14N, expressed
as δ15N) to trace guano incorporation in the intertidal
reef community (fsh and crab). The study areas were the
Saint Peter and Saint Paul Archipelago (SPSPA), a remote
and very small group of islets in the equatorial Atlantic
Ocean, and two reference Atlantic islands where intertidal
environments are not subject to the infuence of guano.
SPSPA intertidal reef fauna presented 3–7‰ higher δ15N
values in comparison with local seabirds and with the
intertidal reef fauna of reference islands. The intertidal food
web of SPSPA appears supplemented by guano subsidies
with carnivores, omnivores and herbivores 15N-enriched in
relation to a local seabird. While no diference in intertidal
biota δ15N values was detected between references sites,
15N-enrichement observed for SPSPA intertidal reef fauna
is supported by guano subsidies. With emerged area < 0.02
km2, SPSPA is one of the world’s smallest archipelagos and
only its main islet (Belmonte Island) has a few tidepools
apt to be inhabited by fsh. As guano readily drains into
tidepools and reef crevices adjacent to the seabird colony,
allochthonous nutrients become available and support
habitat-restricted species in this small and isolated location.
Biodiversity and Conservation, 2023
Fishes are conspicuous and threatened components of reef ecosystems. Understanding the role of th... more Fishes are conspicuous and threatened components of reef ecosystems. Understanding the role of the variables that shape their assemblages is important to buffer species, fishery stocks, and habitats from anthropogenic threats. So, the influence of depth and topographic complexity on trophic guilds and body size of reef fishes was assessed by underwater visual censuses (UVCs) conducted in biogenic reefs, rocky reefs, and rhodolith beds interspersed with algae, invertebrates, and sand. The study area lies in the southern continental shelf of Espírito Santo state, Brazil, a region that has lacked thorough UVC surveys of biogenic reefs and rhodolith habitats. A total of 105 species belonging to 42 fish families were registered. Among the eight trophic guilds registered, mobile invertebrate feeders and herbivores were the most representative in terms of density and biomass. Biogenic and rocky reefs showed higher biomass, density and richness than rhodolith habitats due to greater topographic complexity, which promotes more food resources and shelter. The five habitats hosted distinct fish assemblages (guilds and taxonomic diversity) probably because of the varying ability of resources they provide. Nevertheless, all habitats were dominated by species of low trophic level. Large fish, especially macrocarnivores, were mostly found in the deepest zones. This pattern is associated with ecological preferences but could also be strengthened by overfishing on shallower sites, decreasing the abundance of top predators and influencing their depth distribution. Our results provide a baseline for future studies, presenting subsidies for the management of human activities and the conservation of marine ecosystems in southeastern Brazil.
Biodiversity and Conservation, 2022
Rhodolith beds harbor a highly diverse associated biota. The Brazilian coast encompasses the worl... more Rhodolith beds harbor a highly diverse associated biota. The Brazilian coast encompasses the world's largest rhodolith beds of the world that occur along a wide latitudinal expanse, from off the Amazon River mouth in northern Brazil (5°N/49°W) to Santa Catarina State in southern Brazil (27°S/48°W). Although recent studies revealed diverse fish communities dwelling in these megahabitats, profound scientific gaps concerning the fish fauna associated with rhodolith beds at the province scale still persist. Herein, we accessed the biogeographic patterns of fishes associated with rhodolith beds along the Brazilian Biogeographic Province by analyzing a matrix of 168 species versus 17 sites distributed in coastal and oceanic regions. Our results revealed that the biogeographic patterns of fishes associated with rhodolith beds were similar to those previously described for fishes associated with macroalgae beds and coral/rocky reefs. Our findings indicate the eastern coast as a "biogeographical ecotone" between the tropical and subtropical regions, therefore, the most diverse portion of the Brazilian Province considering species richness, functional diversity and endemism. Such remarkable biogeographic transitional zone should be considered as a priority region for conservation. Oppositely, the region suffers from intensive extraction of rhodoliths for the conversion into fertilizers. Conservation strategies/initiatives and longterm monitoring programs are thus urgently needed.
The genus Acyrtus (Gobiesocidae) is represented by four valid species distributed in the western ... more The genus Acyrtus (Gobiesocidae) is represented by four valid species distributed in the western Atlantic, and a recently described fifth species from the eastern Pacific. Here, we describe a new species endemic to Trindade Island, Brazil, and provide the first phylogenetic inference for the genus including all representatives. The new species can be distinguished from all its congeners by meristic and morphometric characters, as well as genetic differences. It presents low genetic diversity and, contrarily to other Trindade Island endemic fishes, shows no evidence of recent population growth. Our phylogeny reveals cryptic species and the paraphyletic nature of Acyrtus, which included Arcos nudus (western Atlantic) in a clade that separated from Arcos erythrops (tropical eastern Pacific) around 20 Mya. The three species found in the Brazilian Province, including one that remains undescribed, form a monophyletic clade which colonized the western South Atlantic around 2.6 Mya. Our study suggests that Arcos nudus should be placed in Acyrtus, and that the relationships among the closely-related Gobiesocidae genera Acyrtus (mostly from the Atlantic Ocean) and Arcos (from the Pacific Ocean) need further investigation.
Neotropical Ichthyology, 2022
Supplementary material S2: TABLE S2 | Summary of historical human main impacts on the Doce River ... more Supplementary material S2: TABLE S2 | Summary of historical human main impacts on the Doce River basin during the 20th and 21st centuries – for purpose of Fig. 4.
Neotropical Ichthyology, 2022
supplementary Material S1: List of fishes of Doce River estuary with additional information abou... more supplementary Material S1: List of fishes of Doce River estuary with additional information about collection year, fishing gear, vouchers and references for trophic guild.
Neotropical Ichthyology, 2022
The Doce River has undergone severe changes over the last centuries (e.g., flow regulation, pollu... more The Doce River has undergone severe changes over the last centuries (e.g., flow regulation, pollution, habitat and species loss). Here, we present the first comprehensive fish biodiversity assessment of the Doce River estuary and a summary of the main impacts and their drivers for the whole river since the early 18th century. C arangiformes, Siluriformes and Eupercaria incertae sedis were the most representative orders for the 115 species recorded. Most species are native (87.8%), euryhaline/peripheral (80%) and zoobenthivorous (33.9%). Threatened (Paragenidens grandoculis, Genidens barbus, and Lutjanus cyanopterus) and near threatened (Cynoscion acoupa, Dormitator maculatus, Lutjanus jocu, Lutjanus synagris, and Mugil liza) species are peripheral. Thirteen species are exotic at the country (Butis koilomatodon, Coptodon rendalli, and Oreochromis niloticus) or the basin level (e.g., Pygocentrus nattereri and Salminus brasiliensis). The catfish Cathorops cf. arenatus is reported for the first time on the eastern coast of Brazil and Paragenidens grandoculis, considered extinct in the Doce River, was discovered in the estuary.
Neotropical Ichthyology, 2022
Material Supplementar
Neotropical Ichthyology, 2022
The genus Acyrtus (Gobiesocidae) is represented by four valid species distributed in the western ... more The genus Acyrtus (Gobiesocidae) is represented by four valid species distributed in the western Atlantic, and a recently described fifth species from the eastern Pacific. Here, we describe a new species endemic to Trindade Island, Brazil, and provide the first phylogenetic inference for the genus including all representatives. The new species can be distinguished from all its congeners by meristic and morphometric characters, as well as genetic differences. It presents low genetic diversity and, contrarily to other Trindade Island endemic fishes, shows no evidence of recent population growth. Our phylogeny reveals cryptic species and the paraphyletic nature of Acyrtus, which included Arcos nudus (western Atlantic) in a clade that separated from Arcos erythrops (tropical eastern Pacific) around 20 Mya. The three species found in the Brazilian Province, including one that remains undescribed, form a monophyletic clade which colonized the western South Atlantic around 2.6 Mya. Our study suggests that Arcos nudus should be placed in Acyrtus, and that the relationships among the closely-related Gobiesocidae genera Acyrtus (mostly from the Atlantic Ocean) and Arcos (from the Pacific Ocean) need further investigation.
SUPPLEMENTARY MATERIAL ( 1 to 4) to Niche availability and habitat affinities of the red porgy Pa... more SUPPLEMENTARY MATERIAL ( 1 to 4) to Niche availability and habitat affinities of the red porgy Pagrus pagrus (Linnaeus, 1758): An important ecological player on the world's largest rhodolith beds
SUPPLEMENTARY MATERIAL to Ecological Links between Pelagic and Mesophotic Reef Fishes in an Ocean... more SUPPLEMENTARY MATERIAL to Ecological Links between Pelagic and Mesophotic Reef Fishes in an Oceanic Archipelago of the Equatorial Atlantic Ocean
SUPPLEMENTARY MATERIAL to Limited human access is linked to higher effectiveness in a marine sanc... more SUPPLEMENTARY MATERIAL to Limited human access is linked to higher effectiveness in a marine sanctuary
SUPPLEMENTARY MATERIAL to The evolutionary history of Priolepis (Gobiidae) in the Atlantic Ocean
SUPPLEMENTAR MATERIAL TO Variability in nearshore fih biodiversity indicators after a mining disa... more SUPPLEMENTAR MATERIAL TO Variability in nearshore fih biodiversity indicators after a mining disaster in eastern Brazil
SUPPLEMENTAR MATERIAL to Marine fish assemblages of Eastern Brazil: An update after the world's l... more SUPPLEMENTAR MATERIAL to Marine fish assemblages of Eastern Brazil: An update after the world's largest mining disaster .....
Journal of Environmental Management, 2022
Marine Protected Areas (MPAs) are a widely used tool for coral reefs conservation, but massive to... more Marine Protected Areas (MPAs) are a widely used tool for coral reefs conservation, but massive tourism activities inside MPAs worldwide can challenge their effectiveness. This study investigated the role of different levels of protection strictness (no-entry, low and high tourism-allowed zones) set for a marine sanctuary in shaping benthic cover and reef fish community structure in the richest and largest coral reef system of the Southwestern Atlantic. Reef fish community structure and benthic cover differed between protection levels. No-entry zones showed significant higher coral coverage and biomass of piscivores and herbivores than tourism-allowed zones. Highest differences were found between no-entry and high tourism intensity zones. Despite the fact that protection from fishing by itself can ensure conservation benefits, we show here that the establishment of no-entry zones improve MPAs effectiveness.
Fisheries Management and Ecology, 2022
Fishing monitoring to gather fishery dynamic data is usually land-based or carried from onboard i... more Fishing monitoring to gather fishery dynamic data is usually land-based or carried from onboard inspections. However, direct georeferencing of fishing activities using aerial drones is a versatile and easy option that can potentially improve fishery studies, especially in Marine Protected Areas. We investigated the utility of aerial images to understand spatial displacement and fishing territoriality in a Brazilian MPA system under risk of deregulation. Survey flights were conducted in the multiple use area where fishing is allowed in the Fernando de Noronha Archipelago, located in the South Atlantic Ocean and considered one of the main ecotourism destinations and marine conservation sites in Brazil. An aircraft was used to map and detect several aspects of fishing activities and shallow seabed characteristics to demonstrate its utility for fishery management. We recorded 89 fishing activities in the marine area and 75 shore fishers on beaches. Results documented areas most intensively targeted by fishers, and operational aspects of fishing effort, both onboard and shoreline activities targeting shoals. Enforcement and monitoring efforts must be strengthened to assess the impact of expanded fishing activity in this marine sanctuary, mainly due to fading conservation rules imposed by top-down political decisions. This aerial approach demonstrates the utility of quantifying and mapping fishing activities to assist both MPA and fisheries management aligned to benchmarks for biodiversity conservation and human-based demands.
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Papers by Jean-Christophe Joyeux
have drawn the attention of companies and naturalists for
centuries. Among notable efects, allochthonous energy/
matter inputs by seabirds are responsible for shifts in
ecosystem functioning next to colonies. Here, we used
stable isotopes of nitrogen-15 (ratios of 15N: 14N, expressed
as δ15N) to trace guano incorporation in the intertidal
reef community (fsh and crab). The study areas were the
Saint Peter and Saint Paul Archipelago (SPSPA), a remote
and very small group of islets in the equatorial Atlantic
Ocean, and two reference Atlantic islands where intertidal
environments are not subject to the infuence of guano.
SPSPA intertidal reef fauna presented 3–7‰ higher δ15N
values in comparison with local seabirds and with the
intertidal reef fauna of reference islands. The intertidal food
web of SPSPA appears supplemented by guano subsidies
with carnivores, omnivores and herbivores 15N-enriched in
relation to a local seabird. While no diference in intertidal
biota δ15N values was detected between references sites,
15N-enrichement observed for SPSPA intertidal reef fauna
is supported by guano subsidies. With emerged area < 0.02
km2, SPSPA is one of the world’s smallest archipelagos and
only its main islet (Belmonte Island) has a few tidepools
apt to be inhabited by fsh. As guano readily drains into
tidepools and reef crevices adjacent to the seabird colony,
allochthonous nutrients become available and support
habitat-restricted species in this small and isolated location.
have drawn the attention of companies and naturalists for
centuries. Among notable efects, allochthonous energy/
matter inputs by seabirds are responsible for shifts in
ecosystem functioning next to colonies. Here, we used
stable isotopes of nitrogen-15 (ratios of 15N: 14N, expressed
as δ15N) to trace guano incorporation in the intertidal
reef community (fsh and crab). The study areas were the
Saint Peter and Saint Paul Archipelago (SPSPA), a remote
and very small group of islets in the equatorial Atlantic
Ocean, and two reference Atlantic islands where intertidal
environments are not subject to the infuence of guano.
SPSPA intertidal reef fauna presented 3–7‰ higher δ15N
values in comparison with local seabirds and with the
intertidal reef fauna of reference islands. The intertidal food
web of SPSPA appears supplemented by guano subsidies
with carnivores, omnivores and herbivores 15N-enriched in
relation to a local seabird. While no diference in intertidal
biota δ15N values was detected between references sites,
15N-enrichement observed for SPSPA intertidal reef fauna
is supported by guano subsidies. With emerged area < 0.02
km2, SPSPA is one of the world’s smallest archipelagos and
only its main islet (Belmonte Island) has a few tidepools
apt to be inhabited by fsh. As guano readily drains into
tidepools and reef crevices adjacent to the seabird colony,
allochthonous nutrients become available and support
habitat-restricted species in this small and isolated location.