Salmo fahrettini, a new species, is distributed in the northern tributaries of the Euphrates River. It differs from other Salmo species in adjacent waters by a combination of the following characters: a greyish body; one black spot behind the eye and on the cheek; three to six black spots on the opercle; numerous black spots on the back (missing on the predorsal area), flank and middle part of body

This study investigates the effect of water temperature on the development rate of eggs and larvae, the duration of the endogenous feeding period and its consequences for recruitment of smelt (Osmerus eperlanus) in Dutch lakes IJsselmeer and Markermeer. This study measured temperature‐dependent egg and larval development rates as well as mortality rates from fertilization till the moment of absorption

Limited data pertaining to life history and population connectivity of the data‐deficient southern stingray (Hypanus americanus) are available. To determine potential vulnerabilities of their populations, this study aimed to analyse their movement patterns and genetic variability. A population of southern stingrays encompassing nine sites around Cape Eleuthera, the Bahamas, has been monitored using

The lionfish, Pterois miles, is one of the most recent Lessepsian immigrants into the Mediterranean Sea and it poses a serious threat to marine ecosystems in the region. This study assesses the basic biology and ecology of lionfish in the Mediterranean, examining morphometrics, reproduction and diet as well as population structure and distribution. The population density of lionfish increased dramatically

Blood sampling via the caudal vasculature is a widely used tool in fish biology for investigating organismal health and physiology. In live fishes, it can provide a quick, easy and relatively non‐invasive method for obtaining a blood sample (c.f. cannulation & cardiac puncture). Here, we provide a general set of recommendations for optimizing the blood sampling protocol that reflects best practices

Multiple paternity seems common within elasmobranchs. Focusing on two deep‐sea shark species: the velvet belly lanternshark, Etmopterus spinax, and the slendertail lanternshark, Etmopterus molleri, we inferred the paternity in 31 E. spinax litters from Norway (3–18 embryos per litter) and 6 E. molleri litters from Japan (3–6 embryos), using 21 and 10 specific microsatellites, respectively. At least

The anthocyanin delphinidin is a natural compound found as water‐soluble pigment in coloured fruits and berries. Anthocyanin‐rich diets have been proposed to have bone protective effects in humans and mice, but the underlying mechanisms remain unclear. In this study, we used a medaka (Oryzias latipes) osteoporosis model to test the effects of delphinidin on bone cells in vivo. In this model, inducible

Two geographically nonoverlapping species are currently described within the sparid genus Spondyliosoma: Spondyliosoma cantharus (Black Seabream) occurring across Mediterranean and eastern Atlantic waters from NW Europe to Angola and S. emarginatum (Steentjie) considered endemic to southern Africa. To address prominent knowledge gaps this study investigated range‐wide phylogeographic structure across

One of the most frequently applied techniques in zebrafish (D. rerio) research is the visualisation or manipulation of specific cell populations using transgenic reporter lines. The generation of these transgenic zebrafish, displaying cell‐ or tissue‐ specific expression of frequently used fluorophores such as GFP or mCherry, is relatively easy with modern techniques. Fluorophores with different emission

The effect of a dietary phosphorus regime in freshwater on vertebra bone mineralisation was assessed in diploid and triploid Atlantic salmon Salmo salar. Fish were fed either a low phosphorus (LP) diet containing 10.5 g kg‐1 total phosphorus or a normal phosphorus (NP) diet containing 17.4 g kg‐1 total phosphorus from ∼3 to ∼65 g (day 126) in body weight. Two further groups were fed the NP diet from

As a first attempt to assess bone health in cleaner fish production, wild and cultured ballan wrasse Labrus bergylta and lumpfish Cyclopterus lumpus were examined by radiology. In C. lumpus, wild fish (57%) had more vertebra deformities (≥1 deformed vertebrae) than cultured fish (2‐16%). One wild C. lumpus had lordosis and another was missing the tail fin. In L. bergylta, wild fish (11%) had less vertebra

Medaka (O. latipes) and zebrafish (D. rerio) are two teleost fish increasingly used as models to study human skeletal diseases. Although they are similar in size, swimming pattern and many other characteristics, these two species are very distant from an evolutionary point of view (by at least 100 million years). A prominent difference between the skeletons of medaka and zebrafish is the total absence

Coping style is defined as a set of individual physiological and behavioural characteristics that are consistent across time and context. In the zebrafish Danio rerio, as well as in many other animals, several covariations have been established among behavioural, physiological and molecular responses. Nonetheless, not many studies have addressed the consistency in behavioural responses over time starting

Hyphessobrycon chiribiquete n. sp. is described from the Río Caquetá drainage in Colombia and the Río Ucayali drainage in Peru, western Amazon. The new species is diagnosed from its congeners by having the following combination of characters: a conspicuous narrow midlateral stripe, starting on the sides of the body behind the opercle near the lateral line; lateral stripe overlapped anteriorly with

The purpose of this study was to test the effects of high CO2 exposure on wound healing rates in an elasmobranch fish (Urobatis jamaicensis). Small dermal injuries (8 mm biopsy) closed by 22 days post wounding with a decrease in haematocrit. High CO2 exposure (ΔpH = 1.4) did not influence healing rate or haematocrit. Combined, these data provide evidence that minimally invasive scientific procedures

Lutjanid snappers belonging to the subfamilies Apsilinae and Etelinae are commercially valuable components of tropical deepwater fisheries throughout much of the Indo–Pacific region. Based on age assessment using sagittal otoliths, the age‐specific demographic characteristics of four deepwater snappers, Eteis coruscans, Paracaesio caerulea, Pristipomoides filamentosus, and Pristipomoides sieboldii

When considering relationships between genotype and phenotype we frequently ignore the fact that the genome of a typical animal, notably including that of a fish and a human, harbors a huge amount of foreign DNA. Such DNA, in the form of transposable elements, can affect genome function in a major way, and transgene biology needs to be included in our understanding of the genome. Here we examine an

The Cape Horn Biosphere Reserve, one of the last wild areas of the planet, is not exempt from the pressures of global change, such as non‐native species introductions. During 2018 and 2019 we studied the Róbalo river basin in order to update the diversity and distribution of fishes. Here, we report for the first time the native and endangered “Peladillas” Aplochiton taeniatus and the non‐native coho

The European weather loach (Misgurnus fossilis) is a cryptic and poorly known fish species of high conservation concern. The species is experiencing dramatic population collapses across its native range to the point of regional extinction. Although environmental DNA (eDNA)‐based approaches offer clear advantages over conventional field methods for monitoring rare and endangered species, accurate detection

A single albino specimen of the lanternshark, Lucifer's shark (Etmopterus lucifer), is reported here. The specimen was found amongst museum collections, having been captured near Cape Palliser, off the North Island of New Zealand in 1984. Morphometrics are reported, and with no retainment of pigmentation, the specimen is considered a complete albino. This is the first record of albinism for the family

A laboratory flume was constructed to examine substrate effects on aquatic development. The flume was designed as a once through system with a submerged cobble filled corebox. Lake whitefish (Coregonus clupeaformis) embryos and temperature probes were deployed at multiple sites within the cobble and in the open water channel. Embryos were incubated in the flume for two different experimental periods;

Long‐chain polyunsaturated fatty acid biosynthesis, a process to convert C18 polyunsaturated fatty acids to eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or arachidonic acid (ARA) requires the concerted activities of two enzymes, the fatty acyl desaturase (Fads) and elongase (Elovl). This study highlights the cloning, functional characterisation and tissue expression pattern of a Fads and

In the southern Gulf of Mexico, the bonnethead shark, Sphyrna tiburo, is one of the most frequently captured species in landings of small‐scale fisheries. Based on the analysis of two fishery‐dependent sampling periods (1993–1994 and 2007–2014), this study aimed to determine reproductive parameters and identify temporal differences between the two time periods. In the first sampling period (FSP), 776

The onset of piscivory in fish, resulting in a shift from zooplankton or invertebrate to fish prey, was studied on pikeperch (Sander lucioperca) larvae displaying and not displaying piscivorous behaviour at different ages (23, 30, 37, 44 and 52 days post‐hatching) using behavioural (attack, capture and swimming activity), morphological (allometry) and digestive enzymatic (trypsin, α‐amylase and pepsin)

Anadromy was documented in 16 lake trout, Salvelinus namaycush, from Canada's central Arctic using capture data and otolith microchemistry. For the first time, estuarine/marine habitat use was described for five individuals using acoustic telemetry. Age-at-first migration to sea was variable (10-39 years) among individuals and most S. namaycush undertook multiple anadromous migrations within their

Previous results show that juvenile shortnose sturgeon are steady swimmers and, compared with salmonids, generally have low critical swimming (UCrit) and endurance swimming capacities. Most studies on swimming capacities of sturgeon, and other fishes, include those where fish have only been swum once and metrics of swimming performance are assessed (e.g., time swum, speed achieved). Under natural conditions

Length–weight relationships (LWRs) were estimated for 36 mesopelagic fish species collected from the equatorial and tropical Atlantic encompassing several oceanographic regions: oligotrophic, equatorial, Cape Blanc, Cape Verde and the Canary Islands. The sample was composed of myctophids (25 species), gonostomatids (5), sternoptychids (3), stomiids (2) and phosichthyids (1). The species were clustered

In the present study we evaluate the putative cases of sympatric speciation in the genus Herichthys by studying the variation of the head shape using principal component analysis, phylomorphospace and reconstructions of the ancestral states of feeding preferences. Herichthys includes both allopatric as well as sympatric sister-species, as well as sympatric unrelated species and offers thus great potential

Plasma concentrations of progesterone (P4) and 17β‐oestradiol (E2) in juvenile, pre‐ovulatory, early, mid‐ or late pregnancy stages of female blue sharks Prionace glauca were analysed. Concentrations of P4 were significantly higher in pregnant than in non‐pregnant individuals, whereas E2 concentrations increased with embryonic and follicular development. A highly accurate (86.1%) random forest classification

Using social media, the Greenland Institute of Natural Resources collected data on the occurrence of pink salmon (Oncorhynchus gorbuscha) in 2019. Eighty‐four pink salmon were reported from 22 locations across Greenland. This comprised 76 specimens from 2019 and 8 specimens from 2013 to 2018. Of these, 12 were caught in fresh water, and a single pink salmon was from the bottom of the Nuuk Fjord near

Lgp2 (laboratory of genetics and physiology 2) is a cytosolic viral sensor of the RLR (retinoic acid‐inducible gene 1 like receptor) family member without the caspase recruitment domain, having both inhibitory and stimulatory roles in RLR‐signalling pathway. In India, Labeo rohita (rohu) is one of the leading and economically favoured freshwater fish species. Several immunological sentry proteins have

Grey mullets are remarkably characterized by their overall uniform external morphology. Species identification as well as positioning the Mugiliformes in a phylogenetic context is rather difficult. Most recently they were placed in the newly erected Ovalentaria, but more detailed relationships to potential sister taxa were not resolved. Studying the internal morphology, especially the osteology, might

Limia islai, new species of livebearing fish, is described from Lake Miragoane in southwestern Haiti on Hispaniola. The new species herein described has a conspicuous barred pattern consistent in several (4 to 12) black bars along the body, ray 4p serrae of the gonopodium in males with 10 segments and origin of dorsal fin in females slightly behind of origin of anal fin. Although the new species color

A new species of Trichomycterus endemic endemic to the Ribeira de Iguape River basin, southeastern Brazil, is proposed based on morphological and molecular evidence. The new species is diagnosed by having the outer layer of coloration composed of scattered, round, black or dark brown spots smaller or equivalent in size to the eye circumference, eight pectoral-fin rays, 28-29 opercular odontodes, 54-56

A new species of Brachychalcinus is described from the Rio Trombetas basin, Brazil. It differs from congeners by possessing a conspicuous second humeral spot rounded. Additionally, our new species differs from B. nummus, B. orbicularis, and B. reisi by the a higher number of branched dorsal-fin rays, and from B. parnaibae by having a lower head depth. This article is protected by copyright. All rights

Myeloid differentiation factor 88 (Myd88) plays an important role in both innate and adaptive immune response. In this study, the full‐length complementary DNA (cDNA) of myd88 from Misgurnus anguillicaudatus was characterized. The myd88 cDNA is 1333 bp in length and contains an 855 bp open reading frame encoding a predicted protein of 284 amino acids. The predicted protein possesses typical Myd88 domain

Barbus xanthos, new species, is described from the EŞen, Dalaman, Tersakan and Büyük Menderes River in southwestern Anatolia. It differs from other Barbus species in the adjacent basins by having 53-60 lateral line scales, a weakly ossified last unbranched dorsal-fin ray about 33%-50%, numerous small irregular shaped black or dark brown spots smaller than scales, often forming large, black or dark-brown

A new species of Megaleporinus is described from the Rio de Contas, a coastal drainage of eastern Brazil, and its phylogenetic relationships are studied using molecular data. The new species is unique among Anostomidae by possessing two exclusive features: an irregular dark longitudinal stripe from supracleithrum to second midlateral blotch and anterior cranial fontanel partially closed. In addition

Trichomycterus spectrum is described as a new species from the Alejo cave, drained by the Ranchería River basin, in La Guajira department, northeastern Colombia; being the first troglomorphic species described from this region. The new species shows an advanced degree of troglomorphisms expressed as eyes absent, long barbels, and body depigmented. Trichomycterus spectrum is diagnosed by the putatively

The Mekong delta is host to a large number of freshwater species, including a unique group of facultative air breathing Anabantiforms. Of these, the striped snakehead (Channa striata), the climbing perch (Anabas testudineus), the giant gourami (Osphronemus goramy) and the snakeskin gourami (Trichogaster pectoralis) are major contributors to aquaculture production in Vietnam. Here we detail the gastrointestinal

PIT-tagging is commonly used in behavioural studies of fish, although long-term evaluations of effects from tagging under natural conditions are scarce. We PIT-tagged common bream Abramis brama, European perch Perca fluviatilis, pike Esox lucius and roach Rutilus rutilus, released them in their lakes of origin and recaptured them after 103-3269 days. Overall, tagged fish did not differ in condition

This study developed a portable, low-cost field respirometer for measuring oxygen consumption rates of large-bodied fishes. The respirometer performed well in laboratory tests and was used to measure oxygen consumption rates (MO2 ) of bull sharks Carcharhinus leucas (mean: 249.21 ± 58.10 mg O2 kg-1 h-1 at 27.05 °C). Interspecific comparisons and assessments of oxygen degradation curves indicated the

Studies of pulse-type gymnotiform electric fishes have suggested that the electric organ discharge waveforms (EODw) allow individuals to discriminate between conspecific and allospecific signals, but few have approached this experimentally. Here we implement a phase-locked playback technique for a syntopic species pair, Brachyhypopomus gauderio and Gymnotus omarorum. Both species respond to changes

Spatial management of fish populations can potentially be optimised by determining the area of influence of a particular species. We performed an acoustic tagging study implemented on Denis Island in the Seychelles to assess the area of influence of the heavily targeted shoemaker spinefoot, Siganus sutor. We investigated whether this species acts as a mobile link between coral patches and seagrass

The American eel (Anguilla rostrata) is an imperilled fish hypothesized to use conspecific cues, in part, to coordinate long distance migration during their multi-stage life history. Here, holding water and tissue from multiple American eel life stages was collected and analysed for the presence, profile, and concentration of bile acids. Distinct bile acid profiles were identified in glass, elver,

Larval dispersion rather than adult migration generally leads to the worldwide expansion of fishes. Species of the genus Gymnocanthus have expanded geographically while undergoing allopatric speciation. Of this genus, while Gymnocanthus tricuspis inhabits the Arctic Ocean and surrounding area, G. herzensteini and G. intermedius occur around northern Japan. Larval early life histories of G. herzensteini

One specimen of the boreal Clupea harengus (Clupeidae) was caught southerly, in the Gulf of Cádiz (southern Spain), whereas a specimen of the subtropical Epinephelus aeneus (Serranidae) was caught northerly, in Galician waters (north-west of Spain). These catches represent a new southernmost record in the eastern Atlantic for C. harengus and the second northernmost for E. aeneus. The co-occurrence

We assessed the effects of sexual maturity on space use in Atlantic salmon (Salmo salar) parr as facultative early maturation enables us to work on individuals belonging to the same cohort. We monitored the space use of 40 1-year-old males in natura throughout a breeding season. First, mature individuals covered longer distances (absolute and upstream) and located within broader home ranges than immature

Stable nitrogen (δ15 N) and carbon (δ13 C) isotope ratios from muscle, liver and yolk were analysed from the mother and embryos of an ovoviviparous shark, Hexanchus griseus. Embryonic liver and muscle had similar δ15 N and δ13 C ratios or were depleted in heavy isotopes, compared to the same maternal somatic and reproductive yolk tissues, but no relationship existed between δ15 N or δ13 C and embryo

This study reports the phenotypic and genetic differences between individuals of puyen Galaxias maculatus from two sites in the same river basin in Tierra del Fuego National Park, southern South America. Individuals from the two sampling sites presented morphometric and genetic differences. The morphometric differences indicated that individuals from Laguna Negra (LN) were short and more robust and

Humans introduce non-native species by means such as the deliberate release of fish into fresh waters and through commercial trade. The guppy Poecilia reticulata Peters, 1859, is commonly kept in aquaria and controls disease vectors, and now it occurs in many areas outside its natural distribution. Its initial habitat in Brazil was identified, and a study was performed to determine whether the density

Boldness and risk-taking behaviours in animals are important traits to obtain advantages such as habitation, food resources, reproductive success and social dominance. Risk-taking behaviour is influenced by physiological and environmental conditions; however, whether individual fish become bolder by the presence of conspecifics remains unknown. In this study, a light-dark preference test was conducted

We examined the reproductive life history of calico surfperch (Amphistichus koelzi), including mating season, pregnancy, gestation and multiple paternity utilizing restriction site-associated DNA sequencing. Furthermore, we compared the mating season of calico with barred (Amphistichus argenteus), walleye (Hyperprosopon argenteum) and silver (Hyperprosopon ellipticum) surfperches to determine if the

The European river lamprey Lampetra fluviatilis and the European brook lamprey Lampetra planeri (Block 1784) are classified as a paired species, characterized by notably different life histories but morphological similarities. Previous work has further shown limited genetic differentiation between these two species at the mitochondrial DNA level. Here, we expand on this previous work, which focused

Environmental temperature is one of the critical factors affecting fish development. The aim of this study was to examine the impact of three different rearing temperatures (16, 19 and 22°C) throughout the endogenous feeding phase of the Siberian sturgeon Acipenser baerii. This was performed by assessing (a) larval survival and growth; (b) immunofluorescence localization and expression of genes involved

Hemigrammus xaveriellus sp. nov. is described from the upper Río Vaupés basin (Amazon basin), Departamento Guaviare, Colombia. It is distinguished from all congeners by the combination of the following characters: presence of a conspicuous, dark, longitudinal midlateral stripe extending along the body; presence of a conspicuous rounded, horizontally elongated humeral blotch anterior to the beginning

The teleost zebrafish (Danio rerio), an established model for human skeletal diseases, is reared under controlled conditions with defined parameters for temperature and photoperiod. Studies aimed at defining the proper rearing density have been performed with regard to behavioural and physiological stress response, sex ratio and reproduction. Studies concerning the effect of rearing density on the

Within a comparative morphological framework, Hippopotamyrus aelsbroecki, only known from the holotype originating from Lubumbashi, most probably the Lubumbashi River, a left bank subaffluent of the Luapula River, is reallocated to the genus Cyphomyrus. This transfer is motivated by the fact that H. aelsbroecki possesses a rounded or vaulted predorsal profile, an insertion of the dorsal fin far anterior

New collections from the Yangambi Biosphere Reserve (YBR) and Okapi Wildlife Reserve (OWR) revealed the presence of two groups of specimens similar to, but different from Marcusenius moorii. To study both these groups, an integrated morphological and genetic (mtDNA, cytb) approach was used. This study revealed that one of the two groups is conspecific with Marcusenius lambouri, a junior synonym of

Most extant vertebrates display a high variety of tooth and tooth‐like organs (odontodes) that vary in shape, position over the body and nature of composing tissues. The development of these structures is known to involve similar genetic cascades and teeth and odontodes are believed to share a common evolutionary history. Gene expression patterns have previously been compared between mammalian and