Elops Research Articles

Fish species composition, diversity, and migration in the Mekong Delta: a study in the Cua Tieu River, Vietnam.

Southern Vietnam, particularly the Mekong Delta, is popular in inland fish species diversity. In this study, fish species diversity across six stations from the estuary to the upstream of Cua Tieu River, which is situated in the Tien Giang province in Southern Vietnam, has been studied from January 2018 to June 2020. Altogether, 2088 specimens were collected and classified, and these belonged to 115 species, 98 genera, and 54 families of 15 orders that were recognized and identified. The names of species, genera, families, and orders are cited. In the total of 115 species, the Perch-like order (Perciformes) is the most diverse group, with 50 species (consist of 43.48% of total species). The catfish order (Siluriformes) is the second-most diverse group, consisting of 19 species (16.52% of total species). The carp order (Cypriniformes) consists of 8 species (6.96%), and the herring order (Clupeiformes) consists of 7 species (6.09%). Three orders of fishes, needle fish order (Beloniformes), Spiny eel order (Synbranchiformes), and flounder order (Pleuronectiformes), consist of 6 species (5.22%), and other orders consist of 1-3 species (0.87-2.61%). Among the 115 species recorded, 4 species were classified as vulnerable (VU) in the Red Data Book of Viet Nam (2007) (which is 3.48% of the total species collected). These are Elops saurus, Anodontostoma chacunda, Datnioides polota, and Toxotes chatareus. According to the IUCN Red list (2020), 1 species is endangered (EN) (0.87%), 1 species is vulnerable (VU) (0.87%), 3 species of fish are near threatened (NT) (2.61%), 6 species are data deficient (DD) (5.22%), and 58 species are least concern (LC) (50.43%). The result also recorded 41 fish as migratory species (26 freshwater species and 15 marine species), which is 35.65% of total species collected. Some migratory species are important and endemic species of the Mekong River, such as Bagarius yarrelli, Boesemania microlepis, Yasuhikotakia modesta, Cyclocheilos enoplos, Pangasianodon hypophthalmus, Pangasius conchophilus, Pangasius krempfi, Pangasius pleurotaenia, Phalacronotus bleekeri.

Environmental, Biological, and Fishing Factors Influencing Fish Mortality and Development of the Cachirra event, Navío Quebrao Lagoon

Objetive: The present study analyzes environmental, biological and fishing factors incidence in the formation and mortality of the Cachirra event.
 Methodology: We collected samples from fishing nets used by the fishermen of "arranchaderos" community located in Navio Quebrao Lagoon (NQL). IDEAM provided 2017 climatologic data. Physicochemical variables were measured with Spectroquant SQ 118 and other direct measurement electronic devices. SPSS statistical software version 24.0 was used to analyze data and their relationships.
 Results: 12 species intervene in the formation of the Cachirra event, predominantly the Mugilidae family. Salinity was the physicochemical variable that most affected the mortality of the species -October (6.0 PSU) and March (67.4 PSU)-. Conclusions: Fishes die according to their susceptibility to salinity changes, being the most susceptible species Cathrorops spixii and Eugerres plumieri, and the most resistant Elops saurus and Mugil liza. The species present in NQL have sizes well below commercial significance and different condition factor values and repletion index values before and after the Cachirra event.

Phylogenetic Origins and Age-Based Proportions of Malacho (Elops smithi) Relative to Ladyfish (Elops saurus): Species on the Move in the Western Gulf of Mexico

Two species of ladyfish occur in the Gulf of Mexico (GOM), Elops saurus and Elops smithi, that are morphologically indistinguishable except for vertebral counts but can also be identified by mitochondrial DNA haplotypes. Here we expand on previous work, most of which has occurred in Florida, and examine the demography, phylogenetics, geographic distribution, and age—structure of ladyfishes in Texas estuaries. Fishery—independent gill net data demonstrated that ladyfishes increase in abundance from north to south along the Texas coast. The abundance of ladyfishes also increased in Texas waters from 1982–2021, which coincides with recent trends of warmer winters. Genetic data confirmed that both E. saurus and E. smithi occur in Texas waters; however, E. smithi was far less common. Contrary to previous research, we observed higher levels of genetic diversity in E. saurus due to larger sample size and thorough sampling of the western portion of its geographic range. Phylogenetic analysis supported the existence of E. saurus as a distinct species but indicated that E. smithi may be paraphyletic with other species of Elops. Otolith analysis showed that the ages of E. saurus and E. smithi ranged from 0–3 years. The lack of individuals > age—3 suggests that ladyfishes migrate to the offshore GOM at age 3 and do not return to coastal areas. This study enhances knowledge of the biology of ladyfishes in inshore waters of the northwestern GOM. Future management would benefit from expanding this research to the entire geographic range of the genus Elops.

PERFIL DOS PESCADORES RECREATIVOS NA LAGUNA DA JANSEN, SÃO LUÍS, ESTADO DO MARANHÃO

This study provided to analyze the profile of recreational fishermen who frequent Laguna da Jansen on the island of São Luís - MA, Eastern Amazon, because of the socio-economic importance of the activity as an important source of employment and income. Data were collected from June to August 2020 from semi-structured online interviews applied to the study’s target audience using the “snowball” method. 78 questionnaires were applied, of which 95% were men, aged between 26-35 years (35%), 40% with professional occupation in the private sector, and average monthly salary ranging from 1 to 3 minimum wages (47%). Most of the interviewees use: reel and spinning reels (31%), with artificial baits (54%) and landed fishing (37%). They have the snnoks Centropomus spp. (34%), the tarpon Megalops atlanticus (31%), and the ladyfish Elops saurus (15%) as target species. Recreational fishing in Laguna da Jansen has shown to be very promising, but it needs improvements in the local infrastructure, such as the construction of a fishing pier, kiosks with specific stores for fishing materials, and selling food products, cleaning, public lighting, and treatment of domestic effluents and improving the system for opening and closing the gates, optimizing the flow of water exchange, and minimizing eutrophication due to the accumulation of organic matter and other organic and inorganic compounds.

Fisheries discard as an alternative for agricultural feed in the state of Campeche, Mexico

Objective: To determine the incidence of non-target fishing species, in riparianfishing, as a dietary alternative for the agricultural sector in the state of Campeche,Mexico.Design / methodology / approach: The ports surveyed in the state of Campeche:Champotón, Seybaplaya and Campeche. A total of 89 questionnaires were appliedat random and at the free will to participate to coastal fishermen. The obtained datawere analyzed with the R vr 3.4.4 statistical software.Results: The results showed that the coastal fishing catch is 760.1 kg onaverage/week, and fishing discards of 30.42 kg/week. Of the bycatch, 68.8% isdiscarded and the rest sold at a low price (US $ 0.2). Among the waste products,234 species stand out, but seven represent the 58.7% of maximum incidence,mainly Bosh Ariopsis felis, Chac-chi Haemulon plumierii, Cojinuda Caranx crysos,Ixpil Upeneus sp., Macabi Elops saurus, Postà Bairdiella chrysoura and SardinaHerengula jaguana.Delimitations / implications: There is a wide variety of species of which theirpotential as a protein source is unknown, which can be used as input in feed.Findings / conclusions: Registered fishing discards are made up of more than 30non-target species and according to their incidence can be considered as inputs infeed manufacturing for the agricultural sector.

Far from home....the first documented capture of the genus Elops (Actinopterygii, Elopidae) from the Mediterranean

Far from home....the first documented capture of the genus Elops (Actinopterygii, Elopidae) from the Mediterranean

Seasonal variation on diet of juvenile Elops saurus Linnaeus, 1766 (Ladyfish) in the Parnaiba River Delta

Abstract: Aim Identify seasonal variations in the diet of juvenile living in the estuary of the Parnaíba River Delta. Methods Food items were identified through analysis of stomach contents, and later submitted to analysis by regular methods for Frequency of Occurrence (FO), Frequency Numerical (FN), Gravimetric Frequency (FW) and Relative Importance Index (IRI). Results Juvenile diet of Elops saurus that inhabit the lagoons in the Parnaíba delta was composed in order decreasing of importance by Osteichthyes (Teleostei), Insecta and Crustacea in addition to Polychaeta and Nematoda. It was also observed a high frequency of occurrence of fragments of plastics in the diet. In the rainy season, 17 items were recorded in the diet, whereas in the dry season only 7 items were present. Relative Importance Index showed high presence of the Teleostei fish (69.93%) on diet of E. saurus during the rainy season, whereas during the dry period the insects of the families Corixidae (43.25%) and Dysticidae (39.16%). Conclusions With the study it was possible to identify that juvenile are piscivorous in the rainy season when there is a higher availability of prey in the environment and insectivores in the dry season when it reduces the supply of food, indicating feeding flexibility to environmental alterations.

Range distribution and contributions to taxonomy of Elops smithi (ELOPIFORMES: ELOPIDAE).

This study presents the first record of Elops smithi for northern Brazil. The evidence suggests this species is being misidentified incorrectly as Elops saurus in estuaries of the Western Atlantic Ocean. Here, morphological, molecular, and cytogenetic evidence identified all ladyfish specimens from one estuary in the region as E. smithi. Thus, at least Elops smithi occurs in the northern coast of Brazil and it is recommended that specimens from this region identified as E. saurus be further investigated with genetic and cytogenetic tools in order to assure a correct species identification.

Evaluation of Mercury, Lead, Arsenic, and Cadmium in Some Species of Fish in the Atrato River Delta, Gulf of Urabá, Colombian Caribbean

The concentrations of mercury, lead, cadmium, and arsenic were evaluated in 96 samples, 12 by each one of the following eight fish species: snook (Centropomus undecimalis), crevalle jack (Caranx hippos), Serra Spanish mackerel (Scomberomorus brasiliensis), southern red snapper (Lutjanus purpureus), blue runner (Caranx crysos), Atlantic tarpon (Megalops atlanticus), ladyfish (Elops saurus), and Atlantic goliath grouper (Epinephelus itajara), which were collected during 1 year in the Atrato River Delta in the Gulf of Uraba, Colombian Caribbean. Three fish were caught from each of the following sites the community usually uses to catch them (known as fishing grounds): Bahia Candelaria, Bahia Marirrio, Bocas del Roto, and Bocas del Atrato. The quantification of metals was performed by microwave-induced plasma-optical emission spectrometry. The Pb concentration fluctuated from 0.672 to 3.110 mg kg−1, surpassing the maximum permissible limit (MPL = 0.3 mg kg−1) for human consumption for all species. The Hg concentration ranged between < Limit of detection and 6.303 mg kg−1, and in the crevalle jack and Atlantic tarpon, concentrations exceeded the MPL (0.5 mg kg−1). The levels of Cd and As were not significant in the studied species and did not exceed the MPL (0.05 mg kg−1).

Contrasting Mercury Bioavailability in the Marine and Fluvial Dominated Areas of the Jaguaribe River Basin, Ceará, Brazil.

This study evaluates the influence of environmental and biological factors upon the mercury (Hg) concentrations in the aquatic fauna in the Lower Jaguaribe River Basin (LJRB) - NE, Brazil. Two campaigns conducted in 2015 in the fluvial (FDA) and in the marine-dominated (MDA) areas resulted in 830 organisms from 16 species collected (nine of finfish and seven of invertebrates). Among the invertebrates, the highest Hg concentration occurred in the crab Callinectes bocourti (201ngg-1), while among the finfish the highest concentration was found in the ladyfish Elops saurus (109ngg-1), both carnivorous and of high trophic level (TL). Intra-specific comparison showed significant higher Hg concentrations in individuals captured in the MDA. Also, Hg bioaccumulation rate in the shrimp Litopenaeus vannamei was much higher in the MDA. These results, point to a concomitant control of Hg bioavailability by physical-chemical variables along the estuarine gradient of the LJRB.

Stocks Discrimination in Lady Fish, Elops machnata (Forskal, 1775) from Southeast and Southwest Coast of India Based on Morphometric and Meristic Analysis

Morphometric and meristic analysis of ladyfish, Elops machnata, were used to discriminate stocks along the Southeast and Southwest coast estuaries of India. Morphometric and meristic analyses showed a similar pattern of differentiation between E. machnata stocks and revealed a clear discreteness of two groups, an East coast (Marakanam, Parangipettai and Muthupettai) population and a West coast (Cochin) population. Higher total length (TL) (28.00 ± 7.043 cm), fork length (FL) (89.27 ± 2.201% TL) and standard length (SL) (81.77 ± 2.582% TL) were recorded in Cochin population and they were significantly different from the other three populations. Meristic counts were relatively homogenous in all the studied populations. No significant variation was found in counts of dorsal fin ray (DFR), anal fin ray (AFR), pectoral fin ray (PFR) and pelvic fin ray (PLFR). The first and second components (PCA analysis) accounted for about 92.2% of variation in all the morphometric characters. Among them, pre pectoral length (PPL) and pre dorsal length (PDL) showed high loading values in PC1 in all four populations. The overall random assignment of individuals to their original group was higher in morphometric than in meristic analysis. Such a presumption could be authenticated henceforth with molecular markers. Hence, further studies, using molecular markers are still required to precisely evaluate the genetic structure of E. machnata along the Indian coast.

A LATE SANTONIAN FISH-FAUNA FROM THE EUTAW FORMATION OF ALABAMA RECONSTRUCTED FROM OTOLITHS

The otoliths described here from the Late Santonian of the Eutaw Formation of Alabama, represent one of the earliest association of teleost otoliths known from North America and it is remarkable for its good preservation and species diversity. They were collected by the late C.K. Lamber in 1969 from a road cut on the Hurtsboro-Marvyn highway south of Marvyn in Russell County, eastern Alabama. It contains 18 taxa based on sagittae otoliths, of which 14 are identifiable to the species level, 10 species are new to science and five new genera. The new otolith-based genera are: Allogenartina n. gen. (Stomiiformes family indet.), Pseudotrichiurus n. gen. (Aulopiformes family indet.), Eutawichthys n. gen. (Beryciformes family indet.), Cowetaichthys n. gen. (Polymixiidae) and Vox n. gen. (Teleostei family indet.); the new species are: Elops eutawanus n. sp., Genartina cretacea n. sp., Allogenartina muscogeei n. sp., Pseudotrichiurus sagax n. sp., Apateodus ? assisi n. sp., Eutawichthys compressus n. sp., Eutawichthys stringeri n. sp., Cowetaichthys alabamae n. sp., Cowetaichthys lamberi n. sp. and Vox thlotlo n. sp. In addition, 8 different morphologies are recognized based on lapilli otoliths, which however cannot be identified to a distinct taxonomic level except for a species of the Ariidae. Two taxa can be related to otoliths recently recorded in situ, pertaining to the genera Osmeroides and Apateodus. The otolith association bears much similarity with those of the Campanian to Maastrichtian of the USA described previously as indicated by the dominance of otoliths of the genera Eutawichthys and Osmeroides . Differences with those faunas are on the species level as well as in the accessory components. The abundance of otoliths of the albuliforms ( Osmeroides ), putative stomiiforms ( Allogenartina ), beryciform ( Eutawichthys ) and polymixiids ( Cowetaichthys ) characterizes a rather stable faunal composition through the entire Late Cretaceous of locations studied in the USA. The conundrum of interpreting the systematic position of isolated Late Cretaceous otoliths is discussed and the findings are correlated with the rich fish fauna known from articulated skeletons of the coeval Niobrara Formation. We consider the taxonomic position of the majority of isolated otoliths to be more or less consistent with the skeletal findings, but there are also a few otolith morphologies, which do not seem to have a skeletal equivalent in the Niobrara Formation, e.g. in osteoglossiforms, clupeiforms, stomiiforms and Ariidae.

Physicochemical and microbiological properties of Macabi (Elops saurus)-based sausages added with fibres

Physicochemical and microbiological properties of Macabi (Elops saurus)-based sausages added with fibres

Iron, Copper, and Zinc in Some Fish Species of the Atrato River Delta, Colombian Caribbean

ABSTRACTThe concentrations of iron (Fe), copper (Cu), and zinc (Zn) were evaluated in 96 samples of the following eight fish species: Centropomus undecimalis, Caranx hippos, Scomberomorus brasiliensis, Lutjanus purpureus, Caranx crysos, Megalops atlanticus, Elops saurus, and Epinephelus itajara collected in the Atrato River Delta in the Gulf of Urabá. Three fish were caught from each of the following common fishing grounds: Bahía Candelaria, Bahía Marirrío, Bocas del Roto, and Bocas del Atrato. Fish were captured during a one-year period, with one specimen per species in each climatic period: dry, transient, and wet. The quantification was performed by microwave plasma-atomic emission spectroscopy. The highest levels of Fe and Cu were found in Caranx crysos, and highest level of Zn in Megalops atlanticus. According to the percentage of the daily value per food serving, Caranx crysos and Caranx hippos are good sources of Fe, and Caranx crysos is a good source of Cu.

Species-specific development of retinal architecture in elopomorph fishes: adaptations for harvesting light in the dark

Elopomorph fishes are distinguished in part by a shared leptocephalus larval form. These glass-clear, ribbon-like larvae are remarkably similar across the elopomorpha, yet they mature to radically different forms as adults. Along the timecourse of development, they transition through a variety of spectrally distinct habitats, occupying very different temporal niches as adults - some diurnal predators in high-light environments, others crepuscular, and others nocturnal. We found that in concert with these changes, the retinas of a variety of elopomorph fish change in similarly dramatic ways over the course of development. While the mature bonefish [Albula vulpes (Linnaeus,1758)] retina is specialized for visual tasks in a high-light environment, the Atlantic tarpon (Megalops atlanticus Valenciennes, 1847) and ladyfish (Elops saurus Linnaeus,1766) exhibit multiple specializations for function at night or otherwise in very dim light conditions. These include stacked rod photoreceptors that are gathered into massive bundles, retinomotor movement of photoreceptor outer segments, and a highly reflective tapetum. In the adult form, the speckled worm eel (Myrophis punctatus Lutken, 1852) maintains a retina with nearly all rods. The dramatic divergence among taxa over the course of development produces species with distinctly specialized visual capabilities. Moreover, the ability to change over the course of development may underlie the capacity for resilience in the face of anthropogenic insults, including light pollution in increasingly developed coastal zones. On the other hand, if light history can drive retinal change, exposure to artificial light at night may be detrimental to the survival of individuals that move between light-polluted and naturally dark locations.

Estuarine fish behavior around slotted water control structures in a managed salt marsh

Estuaries are composed of multiple interconnected habitat types used by transient fish species during their period of estuarine residency. Structural marsh management restricts habitat connectivity and impedes the movement of fishes among these habitat types by limiting access via water control structures (WCSs) between the managed area and the rest of the estuary. While some general information on fish passage rates is available, species-specific information on passage through WCSs is lacking for salt marsh fishes. We monitored tagged fishes from March 2012 through November 2013 using passive integrated transponder antenna arrays at two identical WCSs in the Calcasieu Lake estuary, Louisiana, USA, to assess the effect of slotted WCSs on fish behavior. A total of 420 individuals of 15 species was tagged and released at the WCSs; of these, 145 individuals representing 11 species were later detected at the WCSs. Five species comprised most (93%) of the detected individuals: Elops saurus (n = 60), Mugil cephalus (n = 43), Sciaenops ocellatus (n = 20), Pogonias cromis (n = 7), and Ariopsis felis (n = 5). Passage rates were low, with most of the observed fishes (n = 80) passing only once through the structures. Other than E. saurus, which was only observed migrating out of the managed marsh, no clear pattern in swimming direction was observed for the other species. Detected species were all present primarily during the summer and fall, however, diel activity at the structures varied by species. The WCSs in our study area appeared to attract and congregate fishes, functioning more like ecological hotspots, rather than simply facilitating fish passage.

Design, technical aspects and operation of cast net without central line and without pockets of Ratnagiri, Maharashtra

The present study encompasses the traditional fishing method of cast net practiced in Ratnagiri, Maharashtra. Cast net without central line and without pockets were made up of 3 to 6 panels joined together vertically by take up ratios to form main conical webbing. PA monofilament having diameter of 0.5 to 1.3 mm was commonly used for construction of main webbing of cast net. Two rows of selvedge meshes of PA multifilament of 210 D×3×3 were provided at bottom edge of the net. Selvedge was absent at the apex end of the net. For all panels of main webbing and for selvedge section, mesh size varied from 20 to 40 mm. At apex, all meshes were closed together and were tied to the pulling chord which was made up of PP twisted multifilament rope of 3 to 4 mm diameter and 4 to 7 m in length. For first three panels, joining of the panels was carried out by 1:2 ratio by making knot locally called as Vasan. From panel number 4 to 6 the ratio was maintained as 2:3. The total depth of net varied from 3 to 5 m. PP twisted multifilament rope of 18 to 26 m in length having diameter of 3 to 5 cm was used as sinker line to which oval shaped lead sinkers having 3 to 4 mm diameter and 180 to 225 in numbers were tied at 12 to 16 cm interval. The fish species harvested by the cast net were mullet, lady fish, silver biddies, glass fish, shrimp and crabs.

ASPECTOS BIOLOGICOS Y ECOLOGICOS DEL MACABI ELOPS SAURUS LINNAEUS (PISCES: ELOPIDAE) EN LA CIENAGA GRANDE DE SANTA MARTA Y COSTA ADYACENTE, CARIBE COLOMBIANO

A sample of 1535 individuals of Elops saurus Linnaeus, 1766, from Ciénaga Grande de Santa Marta (CGSM) and the adjacent sea was examined between February 1987 to January 1988 and May 1990 to February 1992. The main meristic and rriorphometric aspects of the species, as well as the size frequency, are presented. The Lenght-Weight relationship obtained was TW= 2.7399*10-ÿLT5 Q931, and the average condition factor K was 4.74. It was determinated that 96% of the sexed individuals were inmature and sexually undifferenciated and that the female-male ratio was 1.5:1. The smallest mature females collected was 520 mm in TL. We conclude that juveniles live in the CGSM and the adults in the sea, where spawning probably takes place during the whole year. Fecundity was estimated in 519400 eggs for 950 mm TL female. Stomach contents analysis suggest that the main component of the diet are engraulidids fish and penaeids shrimp. Some differences were detected in the diet in relation with seasons and size. The permanent capture of juveniles in the CGSM must be controlled in order to protect the population and avoid further unbalance in the fisheries and the ecosystem.

Ontogenic retinal changes in three ecologically distinct elopomorph fishes (Elopomorpha:Teleostei) correlate with light environment and behavior.

Unlike the mammalian retina, the teleost fish retina undergoes persistent neurogenesis from intrinsic stem cells. In marine teleosts, most cone photoreceptor genesis occurs early in the embryonic and larval stages, and rods are added primarily during and after metamorphosis. This study demonstrates a developmental paradigm in elopomorph fishes in which retinas are rod-dominated in larvae, but undergo periods of later cone genesis. Retinal characteristics were compared at different developmental stages among three ecologically distinct elopomorph fishes-ladyfish (Elops saurus), bonefish (Albula vulpes), and speckled worm eel (Myrophis punctatus). The objectives were to improve our understanding of (1) the developmental strategy in the elopomorph retina, (2) the functional architecture of the retina as it relates to ecology, and (3) how the light environment influences photoreceptor genesis. Photoreceptor morphologies, distributions, and spectral absorption were studied at larval, juvenile, and adult stages. Premetamorphic retinas in all three species are rod-dominated, but the retinas of these species undergo dramatic change over the course of development, resulting in juvenile and adult retinal characteristics that correlate closely with ecology. Adult E. saurus has high rod densities, grouped photoreceptors, a reflective tapetum, and longer-wavelength photopigments, supporting vision in turbid, low-light conditions. Adult A. vulpes has high cone densities, low rod densities, and shorter-wavelength photopigments, supporting diurnal vision in shallow, clear water. M. punctatus loses cones during metamorphosis, develops new cones after settlement, and maintains high rod but low cone densities, supporting primarily nocturnal vision. M. punctatus secondary cone genesis occurs rapidly throughout the retina, suggesting a novel mechanism of vertebrate photoreceptor genesis. Finally, in postsettlement M. punctatus, the continuous presence or absence of visible light modulates rod distribution but does not affect secondary cone genesis, suggesting some degree of developmental plasticity influenced by the light environment.

Epural bones in teleost fishes: a problem of phylogenetic homology

In the past, epural bones of teleost fishes have been labeled sequentially from anterior to posterior (e.g., epural 1, epural 2, etc.) without regard to their position relative to centra and ventral elements of the caudal fin. Recent research on caudal fin development of basal teleosts (e.g., Elops saurus and Hiodon spp.) and salmonids (e.g., Thymallus thymallus and Oncorhynchus spp.) indicates that simple numbering of epural bones is not phylogenetically meaningful. Our purpose is to demonstrate that “higher” teleost fishes show a variety of patterns of epural formation and development and that some of these may be phylogenetically informative characters. We describe the early ontogeny of the caudal fin with special reference to the epurals for selected species of teleosts. Development of epurals is detailed beginning with the earliest detection of chondrocytes in growth series of various teleosts. Epurals form after notochord flexion in the examined otomorphs, salmonids, and Mallotus villosus, as well as in Chauliodus macouni and Synodus foetens. Epurals form before flexion in the examined ctenosquamates, which allows for simple association of an epural with a ventral caudal element (i.e., hypural). After notochord flexion, epurals may reposition relative to their corresponding hypurals and this is a factor that can confuse homology assessment in adult specimens. It is recommended that epurals be named using the polyural terminology according to their position relative to ventral caudal elements early in ontogeny (e.g., epural of preural segment 1 or epural of hypural 2).