Morphometric and meristic data were used in this study to establish morphological variations within the largest genetically consistent groups of five wild populations of tilapia from Kyushu and Okinawa ecological regions of Japan. The genetic analysis based on mitochondrial DNA relatedness was used to determine the data range used for the morphological analyses. During the morphological analyses, the

A Correction to this paper has been published: https://doi.org/10.1007/s10641-021-01096-6

The seasonal occurrence and temporal sexual segregation of great white sharks Carcharodon carcharias have been widely documented in various temperate and sub-tropical waters across the globe. Yet, there is limited understanding of the relationship between the life stages and habitat use of C. carcharias, particularly in the Southern Cape. In this study, we investigated the population dynamics of C

This study outfitted wild-caught white seabass (Atractoscion nobilis) with electronic data storage tags (DSTs) to evaluate subsequent movements of adult fish captured along Baja California, Mexico (BC). Cefas G5 DSTs were surgically implanted into 89 wild-caught white seabass ranging in size from 66 to 152 cm TL between La Salina (32.11°N/116.90°W) and San Quintin (30.25°N/115.83°W), BC. Twenty-four

We combined a high-resolution acoustic telemetry array with presence/absence receivers to conduct a preliminary study of the seasonal movements, activity patterns, and habitat associations of the newly described Deacon Rockfish (Sebastes diaconus). Eleven mature female Deacon Rockfish were tagged and monitored during an 11-month period, at a nearshore rocky reef off Seal Rock, Oregon, USA, an area

Species conservation requires a clear understanding of habitat availability and subsequent use of those habitats. In cases where species declines have occurred and gone undetected by conservation managers, habitat alteration, fragmentation, and loss are often the largest contributors. River fragmentation often results in altered flow regimes, subsequently impacting the availability of riverine habitats

Striped Bass naturally inhabit a wide range of temperatures, yet little is known about the processes that control their acute and chronic temperature limits. The objective of this study was to determine the effect of temperature acclimation on acute thermal maxima and physiology of juvenile Striped Bass. Juvenile fish were acclimated to 15, 25 or 30 °C for 4 weeks, then split into two sampling groups:

Giant sea bass (Stereolepis gigas, Polyprionidae) are the largest reef-associated teleost in the northeastern Pacific, considered an important predator in Macrocystis kelp forest and rocky reef ecosystems. Because of the predictability of annual aggregations, giant sea bass (GSB) were fished throughout the twentieth century until they were nearly extirpated from southern California and Baja California

Sockeye salmon that spawn downstream of rearing lakes are an important example of the challenges faced by organisms with complex life histories requiring connectivity in aquatic habitat complexes. Specifically, newly emerged juvenile sockeye salmon must migrate upstream, against the flow of water, if they are to reach lake rearing habitat. Here, we examine the spatial and temporal dynamics of the water

The Potamotrygon from the Potamotrygonidae family is a freshwater stingray that is native to and distributed throughout South American watersheds. The degradation suffered by the environment in recent years, particularly in aquatic habitats, directly affects native fish species. Due to anthropic actions, some species of the genus Potamotrygon are threatened with extinction, encouraging a study on captive

Nurse sharks (Ginglymostoma cirratum, Ginglymostomatidae) are one of the most exhibited shark species in aquariums worldwide. However, in these locations, their reproductive success rate is frequently low. Considering that there is probably an olfactory mediation for nurse shark reproduction, and that environmental enrichment has a potentially positive effect on reproduction of captive animals, the

Much has been written about the abundance of fishes in estuaries, and particularly the value of the littoral zone and associated macrophyte habitats as fish nursery areas. What has not been researched or discussed in the same amount of detail is that estuaries are demanding physico-chemical environments for fishes, yet each year millions of 0 + juveniles are recruited into these supposedly stressful

Our study sought to analyze patterns and overlap in prey items consumed by elasmobranch species in southern Brazil through a complex network analysis. We hypothesized that species with the same habitat use would show greater trophic niche overlap and lower diet specialization than species with different habitat use. We conducted a literature survey of the species recorded in southern Brazil and analyzed

Eel movement patterns have been frequently studied to learn about their movements within the fresh- and brackish waters of the same river before their spawning migrations. Although otolith microchemistry analyses estimated that the eels used fresh-, brackish, and marine water habitats, inter-river movements of Japanese eels via the sea have not been observed. In previous studies silver eels appear

Many fish spawn in aggregations, but little is understood about the dynamics governing the success of spawning interactions. Here, we evaluate the influence that location of lek-like mating territories has on spawning interactions of Gomphosus varius. We used direct observations of spawning and egg predation events as well as local population counts to compare the rates of spawning, spawning interruptions

Many tropical fisheries are data-poor and lack population demographic information needed for effective management and conservation. In this study we used mark-recapture of bonefish, Albula vulpes, an important species in catch-and-release recreational fisheries, to estimate capture probabilities. Moreover, for the first time we generated key demographic parameters including apparent survival, new entries

Population declines and demographic changes of Chinook salmon (Oncorhynchus tshawytscha), have been documented throughout this species’ range, though information on natural and anthropogenic mechanisms related to these changes are not fully understood. To provide insights into marine behaviors and survival of Chinook salmon, 40 pop-up satellite archival tags (PSATs), that collected environmental data

The potential use of Sr/Ca and Ba/Ca ratios in fish otolith, as a complement to 87Sr/86Sr to study movements of Prochilodus lineatus, was evaluated in the La Plata Basin (South America). Water ratios were obtained from samples collected during the high and low water seasons at 42 sites across the La Plata Basin. Elemental and isotopic ratios in water were measured by MC-ICP-MS, ICP-MS and ion chromatography

Topmouth culter (Culter alburnus) is an economically important fish species distributed in rivers, lakes and reservoirs throughout China. This study focused on the genetic diversity and genetic germplasm resources of C. alburnus populations. We developed a set of 14 polymorphic multi-nucleotide repeat microsatellites using specific locus amplification fragment sequencing (SLAF-seq). Based on microsatellites

While it is common knowledge that Red Drum (Sciaenops ocellatus) inhabit oligohaline waters (salinity <5), lifetime reconstructions of salinity histories have been lacking, and this study provides unique insight into interannual and ontogenetic patterns of oligohaline occupancy by this economically valuable sportfish. Growth consequences of oligohaline exposure and the relationship of oligohaline residency

We evaluated how genotype (stock source, parental line, chromosomal sex) and temperature interact to influence gonad development and phenotypic sex of Oncorhynchus mykiss. Embryos were generated from single pair matings of natural-origin and first-generation hatchery-origin O. mykiss held at ambient or elevated (5 °C above ambient) water temperature. Exposure to elevated temperature lasted from fertilization

Decreasing river flows and increasing water temperatures during the summer have been associated with holding behavior by pre-spawning Pacific lamprey Entosphenus tridentatus in the mainstem Willamette River (Oregon, USA). However, it is unclear if microhabitat use (≤ 2 m) by these lamprey is associated with particular habitat structure(s) or thermal refuge. We implanted radio tags into lamprey (n = 425)

We compared body morphology of two freshwater sculpin taxa that inhabit distinct environmental conditions in the Chesapeake Bay watershed of eastern North America: Potomac sculpin (C. girardi, Robins; PS) and checkered sculpin (C. sp. cf. girardi; CS). Both taxa are endemic to the study area, but PS are more broadly distributed than CS which are limited to karst groundwater-dominated streams in the

Shorthead sculpin (Cottus confusus Bailey and Bond, 1963) in Birch Creek, Idaho, were infected with the trematode Euryhelmis cotti (Simon, 1972). Our objective was to determine if intensity of infection had an influence on growth, reproduction, and mortality of shorthead sculpin at two sites in Birch Creek. Prevalence of trematode infection was 100 % at the upstream site compared to 32 % prevalence

Environmental conditions influence ecological processes that shape stream community diversity and abundance. Deforestation has the potential to limit available particulate organic matter and raise stream temperatures. The degree to which tropical stream communities are impacted by these changes is likely to differ between systems, but empirical data from tropical regions are lacking. This lack of baseline

Millerichthys robustus is the only annual killifish distributed in America with phenotypic color variations, not yet described. Accordingly, we first describe the color pattern in both sexes to define its phenotypical variations. We then analyze the frequency of these phenotypes on a geographical scale, in four localities that represent opposite points of Millerichthys’s distribution in the Mexican

Invasions of non-native fishes are recognized as a serious threat to freshwater biodiversity across the globe. Being the China’s second-largest river, the Yellow River has experienced severe invasion pressure of non-native fishes during recent decades. However, much less is known about species composition and distribution of non-native fishes in this river basin. Here, we investigated and summarized

Many river systems have been artificially modified for various reasons worldwide. Although simplified riverbeds due to artificial modifications often alter the species compositions and interactions, methods for mitigating habitat degradation in such rivers are underdeveloped. In this study, we evaluated the effects of tree branches on the survival of juvenile masu salmon Oncorhynchus masou under predation

Many hypoxic freshwater springs have become havens for air-breathing, invasive, loricariid armored catfish. However, this does not seem to be the case for juvenile catfish, which are rarely seen. We wondered if hypoxia and air-breathing influenced habitat selection in juveniles, and so we designed an experiment to test the sensitivity of two size classes of juvenile catfish to varying concentrations

Photo-identification has been proven to be a successful individual recognition tool in seahorse species (e.g., long-snout seahorse Hippocampus reidi (Ginsburg, 1933) and long-snouted seahorse Hippocampus guttulatus (Cuvier, 1829)). Its use was deemed valuable for the assessment of wild populations and to understand variations in abundance over time when capture-recapture methods are needed. In this

Habitat use and diet composition of invasive smallmouth bass, Micropterus dolomieu, Japanese dace, Pseudaspius hakonensis, and pale chub, Opsariichthys platypus, were studied for two years in the Middle Chikuma River, Nagano, Japan. Habitat use of dace and chub overlapped both years but showed differences from smallmouth bass. Additionally, smallmouth bass habitat use differed greatly between years

Age, growth, and reproductive traits of two large emperor fishes Lethrinus olivaceus (n = 144, 26.9–76.8 cm fork length) and L. xanthochilus (n = 127, 24.2–64.8 cm) were investigated in the Yaeyama Islands (24°N, 124°E), Okinawa, southern Japan. Spawning was confirmed from April to June for L. olivaceus and April to May for L. xanthochilus. Otolith opaque zones in both species were found to be formed

Psalidodon paranae is an endemic small Characidae from the Upper Paraná River ecoregion (Neotropical region, Brazil), where many watercourses are affected by anthropic activities. The Verde River (VR) was chosen as a model to study the feeding trends of P. paranae. Based on empirical observations, hypotheses were set concerning its occurrence, the environmental representativeness of its diet and the

The timing of migration and breeding is an important aspect in the study of the migratory ecology of fishes. This timing in fish is generally determined by both genetic and environmental factors but is also subject to anthropogenic selection. Hatchery transplantation practices, where hatchery fish are produced from returned adult salmon and then transplanted into several rivers, have been going on

Physiological traits are key determinants of species success in any given environment. Competing metabolic demands can influence success by limiting the available scope for aerobically-demanding activities, including reproduction and dispersal. The present study investigated whether the aerobic performance of Gambusia holbrooki, one of the most invasive species in the world, was affected by the embryonic

Many animals are sexually dimorphic, whereby males may display brighter body coloration and more distinctive ornamentation than females. Fishes in temperate regions markedly change their energy allocation toward reproduction in response to the seasonal environment. Seasonal change in reproductive investment affects the expression of sexually dimorphic traits in males through gonadal weight change.

The spatial distribution of phenotypes across the environment has important consequences for population biology, community ecology, and evolution. Populations of pumpkinseed sunfish (Centrarchidae: Lepomis gibbosus) have repeatedly diversified between the littoral and pelagic habitats of postglacial lakes, but we know little about the natural history of pumpkinseed in exposed rocky littoral shorelines

Billfishes are considered important fishery resources and the identification of aggregation sites is imperative for proper management. Here we present evidence of a seasonal aggregation site for juvenile istiophorid billfishes in southern Brazil. We discuss the results as they relate with the need for management at a local scale and participatory monitoring with artisanal fishing communities as a way

The oviducal gland is a specialised region of the elasmobranch oviduct that is thought to be a site of sperm storage, among other functions. The phenomenon of female sperm storage in elasmobranchs has implications for the understanding of their reproductive ecology and the management of exploited populations, but relatively little information exists on its taxonomic extent. In the present study, oviducal

The chevron butterflyfish, Chaetodon trifascialis, is among the most specialised coral-feeding fish, and while it is known to be very susceptible to extensive depletion of its preferred coral prey (tabular Acropora spp.), their specific responses to changing coral cover are poorly understood. The purpose of this study was to test for variation in territorial behaviour and condition of C. trifascialis

The frequency of reproduction and homing success are crucial in determining the lifetime reproductive fitness of iteroparous salmonids. We examined consecutive spawning and homing by Sakhalin taimen (Parahucho perryi), one of the least-studied iteroparous salmonids. The average consecutive return rate was 69.5%, the highest ever reported for an iteroparous salmonid. The consecutive return rates were

Large dams disrupt river ecosystems, causing negative effects on fish assemblages. Few studies, however, have investigated how Neotropical fish diversity responds to river regulation in longer temporal scales. In this study, we used a multi-metric approach to investigated temporal changes in taxonomic and functional fish diversity over 15 years-period following the construction of a large dam in the

A significant portion of the threatened ichthyofauna is composed by annual fish, whose gene flow is commonly affected by large water bodies. Austrolebias minuano is an endangered species that lives in temporary wetlands of the Patos-Mirim Lagoon System, in Brazil, inhabiting both margins of the Patos Lagoon. This species has previously been target of taxonomic split, leading to the description of A

Population vital rates, such as stage-specific survival, are influenced by individual behavior and movement patterns. Yet few methods exist to incorporate behavior into predator-prey models, omitting a potentially important source of variability in population dynamics. Here were combine results from an acoustic telemetry study of juvenile Chinook salmon (Oncorhynchus tshawytscha) with an existing predator

We studied the post-release activity of newly tagged fish and determined whether and for how long experimental protocol impacted their behavior. Our study focused on three species (Plectropomus leopardus, Chlorurus microrhinos and Scarus ghobban), including a total of 30 fish. Fish were kept outside their natural environment for several days before release for pre- and post-tagging surveys. Moreover

Euryhelmis cotti (Simon, 1972) is an intestinal fluke with a complex life history with three hosts; in the metacercarial stage, E. cotti infects fish in the family Cottidae. Our objective was to determine the distribution, prevalence, and intensity of infection of E. cotti in shorthead sculpin (Cottus confusus Bailey and Bond, 1963) in Birch Creek, Idaho. We collected shorthead sculpin at five sites

Characterization of essential habitat for sharks is a key requirement for effective conservation of shark populations. In Cuba, shark essential habitat is largely undocumented. Here we present the first study of a shark nursery area in Cuban waters, for the lemon shark. Nursery areas for lemon sharks are typically surrounded by mangroves and contain sandy substrate where the young can feed, grow, move

Knowledge on factors influencing traits during critical early growth periods is essential for predicting population persistence. Genetic effects and microhabitat stream conditions at female selected oviposition sites influence larval phenotypes. However, limited work has examined contributions of both factors across sequential ontogenetic stages for larvae of wild origin. Using a wild population of

To assess genetic variation in pink salmon (Oncorhynchus gorbuscha), the polymorphism of nucleotide sequences of the ND2 and Cytb (mtDNA) genes has been analyzed in 404 individuals of even- and odd-year broodlines from 10 temporal samples collected in different years from one river. The data that earlier indicated a high level of genetic differences between samples of the broodlines spawning in even-

The original version of this article unfortunately contained a mistake.

The Niagara River, which connects two Great Lakes (Erie and Ontario) and forms a border between Canada and the United States, has experienced decades of abiotic and biotic disturbance as well as long-term restoration efforts. Given the iconic riverscape and importance as a binational fisheries resource, a biodiversity assessment of the mainstem Niagara River fish assemblage is overdue. Here, fish assemblage

Carotenoid pigments have myriad functions in fish, including coloration and immunity. The “carotenoid trade-off hypothesis” posits that dietary limitation of carotenoids imposes constraints on animals to allocate to one function at the expense of another. This hypothesis rarely has been tested in fish. We quantified tissue carotenoids in breeding and non-breeding female convict cichlids in Lake Xiloá

Temperature is a key determinant that governs fish survival, reproduction, growth and metabolism. In freshwater ecosystems, anthropogenic influences have resulted in acute and prolonged temperature changes which lead to lethal and sub-lethal impacts on the biota that occupy these environments. We assessed the effects of temperature on somatic and otolith growth and development of three species of native

Endemic marine species often exist as metapopulations distributed across several discrete locations, such that their extinction risk is dependent upon population dynamics and persistence at each location. The anemonefish Amphiprion latezonatus is a habitat specialist, endemic to two oceanic islands (Lord Howe and Norfolk) and the adjacent eastern Australian coast from the Sunshine Coast to Southwest

A large number of studies across many different disciplines have been conducted on the Swartvlei estuarine system over the past five decades, thus providing an ideal opportunity to review spatial and temporal aspects of fish food webs in the lower estuary and upper lake. The aquatic and semi-aquatic macrophytes, together with the physico-chemical environment associated with these two parts of the system

The Strawberry Darter Etheostoma fragi is endemic to the Strawberry River drainage in northcentral Arkansas, where its distribution and status have not been assessed since the mid-1990s. A status survey was conducted during the summers of 2015 and 2016. Sixty-four sites were sampled (32 each summer) within the Strawberry River drainage. Sites were surveyed 4 times each using a kick-seine. A total of

Alteration of flow regimes by anthropogenic activities is one of the primary environmental problems in riverine systems. Understanding how hydrologic conditions can affect ontogenetic habitat shifts of imperiled fishes is important in order to develop conservation and management strategies for each life-history stage. We examined relationships between the abundance of young-of-the-year (YOY) Rio Grande

Winter habitat selection by Striped Bass (Morone saxatilis) has been described as opportunistic, but due to the length and severity of winter at its northern range, winter habitats in the north are predicted to be restricted in distribution and carefully selected. Here we describe the locations and environmental conditions supporting winter aggregations of adult Striped Bass including periods under

Spatial and temporal distribution of anadromous alewife (Alosa pseudoharengus Wilson) spawning and nursery habitats were determined by sampling in the Mullica River – Great Bay watershed (New Jersey, USA) in a combination of long- and short-term observational and quantitative studies. Reproduction was confirmed by examination of developing gonads, visual observations of spawning, and egg collections

White Sturgeon (Acipenser transmontanus) are a long-lived, slow-growing, and late-reproducing anadromous fish common in estuaries and coastal habitats along the North American West Coast. These life history characteristics make populations vulnerable to human impacts and a challenge to study and manage. Previous studies in the San Francisco Estuary, California have provided insights into rearing habitats