Age and growth assessment of the near-threatened fish Rita rita (Siluriformes: Bagridae) in the Ganges basin

Introduction: Rita rita is a freshwater catfish under threat of extinction, mainly from loss of breeding and nursing grounds. A reliable method for age and growth estimation is needed by fishery managers. Objective: To identify the best body structure for age and growth estimation. Methods: We assessed estimates precision based on Average Percent Error (APE), Coefficient Variation (CV), and Percent Agreement (PA) between readers separately analyzed each calcified structure. We used 390 fish samples from three rivers, Ganga, Yamuna and Ramganga, from September 2018 to August 2019. Results: The three indicators favored the use of vertebrae for age estimation; the growth band seems to be annual and formed from May to September. The growth equations were Lt = 90.19(1-e-0.145(t+0.51)) for Ganga; Lt = 91.19 (1-e-0.14(t+0.59)) for Yamuna and Lt = 89.63 (1-e-0.15(t+0.68)) for Ramganga. Conclusion: This species reaches moderate growth in these rivers, where vertebrae are the recommended age estimation structure, followed, in case of need, by sectioned otoliths, whole otoliths and opercular bones. Pectoral spines should be avoided, especially in older fish.

Introducción: Rita rita es un pez de agua dulce bajo amenaza de extinción, principalmente por la pérdida de sitios de reproducción y crianza. Un método fiable para las estimaciones de edad y crecimiento es necesario para los administradores de recursos pesqueros. Objetivo: Identificar la mejor estructura corporal para estimaciones de edad y crecimiento. Métodos: Evaluamos la precisión de las estimaciones mediante el Porcentaje de Error Promedio (APE), Coeficiente de Variación (CV), y Porcentaje de Acuerdo (PA) entre lecturas para cada estructura calcificada. Usamos 390 muestras de peces de tres ríos, Ganga, Yamuna y Ramganga, de setiembre 2018 hasta agosto 2019. Resultados: Los tres indicadores favorecieron el uso de vértebras para la estimación de edad; la banda de crecimiento parece ser anual y se forma entre mayo y setiembre. Las ecuaciones de crecimiento fueron Lt = 90.19(1-e-0.145(t+0.51)) para Ganga; Lt = 91.19 (1-e-0.14(t+0.59)) para Yamuna y Lt = 89.63 (1-e-0.15(t+0.68)) para Ramganga. Conclusión: La especie alcanza un crecimiento moderado en estos ríos, dónde las vértebras son la estructura de estimación etaria recomendada, seguido de, en caso de ser necesario, los otolitos segmentados, otolitos enteros y huesos operculares. Debe evitarse el uso de espinas pectorales, especialmente en peces de mayor edad.

Response characteristics of vestibular evoked myogenic potentials recorded over splenius capitis in young adults and adolescents.

BACKGROUND AND OBJECTIVES: Examine vestibular evoked myogenic potential (VEMP) responses recorded from surface electrodes over Splenius Capitis (SPC) in a seated position. SPECIFIC AIMS: (1) validate response characteristics of VEMP recordings from surface electrodes over Sternocleidomastoid (SCM) and over SCP and (2) assess age effects on responses in adolescents and young adults. MATERIALS AND METHODS: Simultaneous surface VEMP was recorded bilaterally from electrodes placed over the dorsal neck musculature at a location known from previous work to record from SPC in 15 healthy participants during trials with head rotation toward and away from the stimulated ear. VEMP was also recorded from electrodes over SCM, ipsilateral to the stimulus ear, in the same participants in a supine, head lift/turn position. RESULTS: Response amplitudes significantly increased with contraction strength and decreased with age. Participants were able to maintain sufficient contraction strength (amplitude) with head rotation to reliably measure over SPC. Normalized response amplitudes measured from electrodes over contralateral SPC were largest with head rotation contralateral to the stimulus ear. Normalized amplitudes and peak latencies were comparable to the same measures from SCM obtained in supine, head lift/turn position. CONCLUSIONS: Otolith generated myogenic responses can be recorded seated from electrodes over the dorsal neck with head rotation contralateral to the stimulus ear. In this position, contralateral recordings are consistent with responses known from previous work to arise from SPC; ipsilateral recordings may include crosstalk from activated muscles nearby, including ipsilateral SCM. Overall, techniques targeting contralateral SPC during contralateral head turn may provide additional methods of recording VEMPs.

Response characteristics of vestibular evoked myogenic potentials recorded over splenius capitis in young adults and adolescents

Background and objectives: Examine vestibular evoked myogenic potential (VEMP) responses recorded from surface electrodes over Splenius Capitis (SPC) in a seated position. Specific aims: (1) validate response characteristics of VEMP recordings from surface electrodes over Sternocleidomastoid (SCM) and over SCP and (2) assess age effects on responses in adolescents and young adults. Materials and methods: Simultaneous surface VEMP was recorded bilaterally from electrodes placed over the dorsal neck musculature at a location known from previous work to record from SPC in 15 healthy participants during trials with head rotation toward and away from the stimulated ear. VEMP was also recorded from electrodes over SCM, ipsilateral to the stimulus ear, in the same participants in a supine, head lift/turn position. Results: Response amplitudes significantly increased with contraction strength and decreased with age. Participants were able to maintain sufficient contraction strength (amplitude) with head rotation to reliably measure over SPC. Normalized response amplitudes measured from electrodes over contralateral SPC were largest with head rotation contralateral to the stimulus ear. Normalized amplitudes and peak latencies were comparable to the same measures from SCM obtained in supine, head lift/turn position. Conclusions: Otolith generated myogenic responses can be recorded seated from electrodes over the dorsal neck with head rotation contralateral to the stimulus ear. In this position, contralateral recordings are consistent with responses known from previous work to arise from SPC; ipsilateral recordings may include crosstalk from activated muscles nearby, including ipsilateral SCM. Overall, techniques targeting contralateral SPC during contralateral head turn may provide additional methods of recording VEMPs.(AU)

Antecedentes y objetivos: Examinamos las respuestas de los potenciales evocados miogénicos vestibulares (PEMV) recogidas de los electrodos de superficie sobre el músculo esplenio (ME) en posición sentada. Objetivos específicos: 1) validar las características de los registros de la respuesta de los PEMV recogidos de los electrodos de superficie sobre el músculo esternocleidomastoideo (SCM) y el ME, y 2) evaluar los efectos de la edad en adolescentes y adultos jóvenes. Materiales y métodos: Se registraron simultáneamente los PEMV bilaterales de los electrodos situados en la musculatura dorsal del cuello, en un sitio conocido de un estudio anterior para obtener registros del ME en 15 participantes sanos durante los ensayos, con rotación de cabeza hacia y fuera del oído estimulado. También se registraron los PEMV de los electrodos situados sobre el SCM, en posición ipsilateral al oído estimulado, en los mismos participantes, en posición supina y con elevación/giro de cabeza. Resultados: Las amplitudes de la respuesta se incrementaron significativamente con la fuerza de la contracción y disminuyeron con la edad. Los participantes fueron capaces de mantener suficiente fuerza de contracción (amplitud) con la rotación de cabeza, para realizar mediciones fiables sobre el ME. Las amplitudes de la respuesta normalizada medidas en los electrodos sobre el ME contralateral fueron mayores con la rotación de cabeza contralateral al oído estimulado. Las amplitudes normalizadas y las latencias máximas fueron comparables a las mismas medidas del SCM obtenidas en posición supina, y elevación/giro de cabeza. Conclusiones: Las respuestas miogénicas generadas por otolitos pueden registrarse en posición sentada a partir de los electrodos situados en la parte dorsal del cuello, contralateral al oído estimulado. En esta posición, los registros contralaterales son coherentes con las respuestas conocidas de un estudio previo, derivadas del ME; los registros ipsilaterales pueden incluir interferencias de los músculos activados cercanos, incluyendo el SCM ipsilateral. En general, las técnicas centradas en el ME contralateral durante el giro de cabeza contralateral pueden aportar métodos adicionales de registro de los PEMV.(AU)

Response characteristics of vestibular evoked myogenic potentials recorded over splenius capitis in young adults and adolescents.

BACKGROUND AND OBJECTIVES: Examine vestibular evoked myogenic potential (VEMP) responses recorded from surface electrodes over Splenius Capitis (SPC) in a seated position. SPECIFIC AIMS: (1) validate response characteristics of VEMP recordings from surface electrodes over Sternocleidomastoid (SCM) and over SCP and (2) assess age effects on responses in adolescents and young adults. MATERIALS AND METHODS: Simultaneous surface VEMP was recorded bilaterally from electrodes placed over the dorsal neck musculature at a location known from previous work to record from SPC in 15 healthy participants during trials with head rotation toward and away from the stimulated ear. VEMP was also recorded from electrodes over SCM, ipsilateral to the stimulus ear, in the same participants in a supine, head lift/turn position. RESULTS: Response amplitudes significantly increased with contraction strength and decreased with age. Participants were able to maintain sufficient contraction strength (amplitude) with head rotation to reliably measure over SPC. Normalized response amplitudes measured from electrodes over contralateral SPC were largest with head rotation contralateral to the stimulus ear. Normalized amplitudes and peak latencies were comparable to the same measures from SCM obtained in supine, head lift/turn position. CONCLUSIONS: Otolith generated myogenic responses can be recorded seated from electrodes over the dorsal neck with head rotation contralateral to the stimulus ear. In this position, contralateral recordings are consistent with responses known from previous work to arise from SPC; ipsilateral recordings may include crosstalk from activated muscles nearby, including ipsilateral SCM. Overall, techniques targeting contralateral SPC during contralateral head turn may provide additional methods of recording VEMPs.

Using otolith weight to predict the age of different stocks of Sperata aor (Siluriformes: Bagridae) from the River Ganga

Estimation of accurate fish age is considered as an essential step for the understanding of life history characteristics, population dynamics, and the management of the fisheries resources. The otolith weight keeps on increasing because of continuous deposition of material on the otolith surface; therefore, otolith measurements are successfully used to infer fish age. The present study was conducted to estimate the relationship between otolith weight and observed age (estimated by counting annuli on the sectioned otoliths) for the stocks of Sperata aor. A total of 315 samples were collected from January 2016 to April 2017 from three different stocks of S. aor i.e. Narora-Kanpur, Varanasi and Bhagalpur from the River Ganga. Linear regression analysis was applied between otolith weight and observed age to predict the age of the fish of each stock from otolith weight. Significant relationships between otolith weight and fish age were observed for the three stocks of the selected fish species from the River Ganga (R2 > 0.9, P 0.05). Overall, 88.5, 88.8, and 87.2 % of the predicted ages were correctly classified to their observed ages for Narora-Kanpur, Varanasi, and Bhagalpur stock, respectively. Thus, it can be concluded that the relationship between otolith weight and fish age can provide a surrogate method of age estimation, and can be used to examine the age structure of the three stocks of S. aor from the River Ganga.

La estimación precisa de la edad de peces es considerada un paso esencial para la evaluación de su historia natural, dinámica de población y manejo de pesquerías. El otolito sigue creciendo debido a la continua deposición de material en la superficie; por lo tanto, las medidas del otolito son un buen indicador para inferir la edad del pez. En este estudio se evaluó la relación entre el peso de los otolitos y la edad observada (estimada contando los anillos de los otolitos seleccionados) de individuos de Sperata aor. En total se recolectaron 315 muestras entre enero 2016 y abril 2017 en tres zonas de S. aor en el Río Ganga (Narora-Kanpur, Varanasi y Bhagalpur). Se aplicó un análisis de regresión lineal entre el peso de los otolitos y la edad observada para predecir la edad de los peces de cada zona a partir del peso de los otolitos. Se observaron relaciones significativas entre el peso de los otolitos y la edad de los peces de las zonas del Río Ganga (R2 > 0.9, P 0.05). En general, 88.5, 88.8 y 87.2% de las edades predichas se clasificaron correctamente con respecto a las edades observadas para Narora-Kanpur, Varanasi y Bhagalpur, respectivamente. Se puede concluir que la relación entre el peso de los otolitos y la edad de los peces puede proveer un método para la estimación de la edad y puede ser usado para examinar la estructura de edades en tres stocks de S. aor en el Río Ganga.

Relationships between fish and otolith dimensions of Pomatomus saltatrix (Linnaeus, 1766) (Perciformes: Pomatomidae) in southeastern Brazil

The bluefish, Pomatomus saltatrix (Linnaeus, 1766), was used as a species-specific model to study morphometric relationships between otolith size and relative growth variables. Length-weight relationships between Otolith (Length-OL, Height-OH, and Weight-OW) and fish measurements (Total Length-TL and Total Weight-TW) were determined for fishes captured monthly during the year 2015 off the southeastern coast of Brazil. The ANCOVA and Kruskal-Wallis analysis did not indicate significant differences in the relative growth constants between sexes and length frequency distributions (p > 0.05). The condition factor also did not present significant differences between sexes, and right and left otolith measurements (p > 0.05). A total of 398 specimens were sampled: TL = 43.6-67.0 cm, TW = 365-2400 g, OL = 9.65-15.25 mm, OH = 3.65 - 5.45 mm and OW = 0.03-0.11 g. The LWR for grouped sexes was TW = 0.050TL2.55 and otoliths OW = 6.17E-05OL2.59. The best adjustments were TL vs OL (r2 = 0.90); OL vs OW (r2 = 0.90); TW vs OW (r2 = 0.81); and TW vs OL (r2 = 0.80). These results showed that such relationships are helpful tools for predicting the fish size and weight from otoliths, which may be used in food habits and paleontology studies, and other fisheries management applications.(AU)

A anchova, Pomatomus saltatrix (Linnaeus, 1766), foi usada como modelo espécie-específico de relações morfométricas de otólitos e variáveis de crescimento relativo. As relações peso-comprimento entre otólito (comprimento-CO, altura-AO e peso-PO) e tamanho do peixe (comprimento total-CT e peso total-PT) foram determinadas para indivíduos capturados mensalmente durante o ano de 2015 na costa sudeste do Brasil. As análises de ANCOVA e Kruskal-Wallis não indicaram diferenças significativas para as constantes de crescimento relativo entre os sexos e distribuições de frequência de comprimento (p> 0,05). O fator de condição também não apresentou diferenças significativas entre os sexos, e medidas do otólito direito e esquerdo (p > 0,05). Um total de 398 espécimes foram amostrados: CT = 43,6-67,0 cm e PT = 365-2400 g. A RPC para peixes foi PT = 0.050CT2,55 e para os seus otólitos foi PO = 6.17E-05CO2,59, CO = 9.65-15.25 mm, AO = 3.65 - 5.45 mm and PO = 0.03-0.11 g. Os melhores ajustes foram observados para CT vs CO (r2 = 0,90); CO vs PO (r2 = 0,90); PT vs PO (r2= 0,81) e PT vs CO (r2 = 0,80). Os resultados mostraram que essas relações são ferramentas úteis na geração de estimativas de tamanho e peso dos peixes a partir dos otólitos, permitindo a sua aplicação em estudos em outras áreas, incluindo hábitos alimentares, paleontologia e manejo da pesca.(AU)

Sexual dimorphism in the catfish Genidens genidens (Siluriformes: Ariidae) based on otolith morphometry and relative growth

Genidens genidens is a species susceptible to population declines in view of their reproductive biology peculiarities. Morphometric differences between sexes are observed in the literature, and these differences should also be evident in otolith development. Growth patterns are one of the most important biological characteristics regarding population dynamics and management. In this context, the aim of the present study is to describe this species relative growth and identify differences between sex life cycles. Somatic growth-otolith growth relationships and somatic length-weight relationships were estimated based on two methodologies; the Huxley and the polyphasic allometric models. Both models demonstrated different growth patterns between sexes. The three axes of otolith growth were adequate descriptors of growth, and the results of the Huxley model demonstrated distinct growth patterns between sexes, with male otoliths larger in all three measured axes. In the polyphase model, male otoliths were thicker, while female otoliths were longer and higher. Both sexes presented similar length-weight relationships, which may indicate that oocyte production and parental care lead to similar costs for this species.(AU)

Genidens genidens é uma espécie suscetível a declínios populacionais, tendo em vista as peculiaridades de sua reprodução. Diferenças morfométricas entre os sexos são observadas na literatura, e essas diferenças também devem ser evidentes no desenvolvimento dos otólitos. O padrão de crescimento é uma das características biológicas mais importantes no que diz respeito à dinâmica populacional e manejo. Assim, nosso objetivo é descrever o crescimento relativo da espécie e identificar diferenças entre os ciclos de vida dos sexos. A relação crescimento somático-crescimento do otólito e a relação comprimento-peso somáticos foram estimados com base em duas metodologias, os modelos alométricos de Huxley e polifásico. Ambos os modelos demonstraram diferentes padrões de crescimento entre sexos. Os três eixos dos otólitos descreveram adequadamente o crescimento, e os resultados do modelo de Huxley demonstraram padrões de crescimento distintos entre os sexos, com os otólitos dos machos sendo maiores em todos os três eixos medidos. No modelo polifásico os otólitos dos machos foram maiores em espessura, enquanto os otólitos das fêmeas exibiram maior comprimento e altura. Ambos os sexos apresentaram relações de comprimento-peso semelhantes, o que pode indicar que a produção de ovócitos e o cuidado parental apresentam custos semelhantes para essa espécie.(AU)

Otolith morphometry provides length and weight predictions and insights about capture sites of Prochilodus lineatus (Characiformes: Prochilodontidae)

Here we choose the sábalo Prochilodus lineatus, to answer the following questions: How the otolith length and weight are correlated to fish measurements (length and weight)? How reliable are the otoliths measurements to predict the length and age of P. lineatus? Finally, we propose predictive equations of the length and weight of the fish using length and weight of the otolith. The otoliths were sampled from individuals collected in the Upper Paraná River floodplain during 2012 and 2013 years. The relationships among the otolith measurements and both length and weight of the fish were performed using linear regressions. To test whether the length and weight of the otolith differ between the sampled sites, Variance Analysis was performed. Finally, we made analysis of Kruskal-Wallis to verify if the measurements obtained through the otoliths could be used to distinguish the age of the fish. We demonstrate that the length and weight of the otolith are good proxies to predict the length and weight of the fish. Although some ages were statistically different, this result does not support the idea that the age of the fish can be accurately inferred only using otolith measures.(AU)

Neste trabalho o curimba Prochilodus lineatus foi utilizado para responder as seguintes questões: Como o comprimento e o peso dos otólitos são correlacionados com o comprimento e o peso do peixe? Até que ponto as medidas dos otólitos são confiáveis para predizer a idade do P. lineatus? Finalmente, nós propomos equações preditivas do comprimento e peso do peixe utilizando o comprimento e o peso do otólito. Os otólitos foram amostrados de indivíduos coletados na planície de inundação do alto rio Paraná durante os anos de 2012 e 2013. As relações entre as medidas dos otólitos e o peso e comprimento do peixe foram verificadas utilizando regressões lineares. Para testar se o comprimento e o peso do otólito diferem entre locais foram utilizadas Análises de Variância e para testar se as medidas dos otólitos são suficientes para distinguir as idades foram utilizados testes de Kruskal-Wallis. Nós demonstramos que o comprimento e o peso do otólito são bons preditores do comprimento e peso do peixe. Embora algumas idades foram estatisticamente diferentes entre as medidas dos otólitos, esse resultado não suporta a ideia de que a idade do peixe pode ser inferida de forma acurada somente utilizando as medidas dos otólitos.(AU)

Impacto de las Maniobras de Reposicionamiento en el grado de discapacidad de pacientes con Vértigo Posicional Paroxístico Benigno del conducto semicircular posterior

Introducción. El Vértigo Posicional Paroxístico Benigno (VPPB) del canal semicircular posterior es una enfermedad crónica que afecta severamente la calidad de vida de los pacientes que lo sufren. Para su manejo existen las Maniobras de Reposicionamiento, que son una serie de ejercicios secuenciales de la cabeza en 4 posiciones. El propósito de la maniobra es reposicionar los otolitos desde el conducto semicircular posterior dentro del vestíbulo a los sitios de donde migraron para dejar de producir vértigo. Permaneciendo en cada posición aproximadamente 30 segundos. Las maniobras han demostrado gran eficacia a corto plazo. Los resultados son medibles por medio de un cuestionario conocido como Dizziness Handicap Inventory (DHI). Objetivos: Medir el impacto de las maniobras de reposicionamiento en la discapacidad en los pacientes con Vértigo Posicional Paroxístico Benigno del conducto semicircular posterior, mediante el uso del DHI. Metodología. Es un estudio comparativo que utiliza la T de Student para muestras pareadas donde cada paciente es su propio control, se tomó una muestra de 20 pacientes diagnosticados con Vértigo Posicional Paroxístico Benigno del conducto semicircular posterior que serán tratados con maniobras de reposicionamiento, serán evaluados mediante la herramienta (DHI) que será completada por los pacientes al inicio del estudio, al día 7 y día 30, luego de realizadas las Maniobras de Reposicionamiento. Resultados: Las mujeres son las más afectadas por el (VPPB) del canal semicircular posterior en una relación de 2.1 aproximadamente. El grado de discapacidad fue medido por el resultado del DHI, el cual muestra para los días 1, 7, y 30 una media de 50.4, 30.4 y 24.2 respectivamente. La escala con mayor punteo durante los días 1, 7, y 30 fue la escala funcional mostrando una media de 20, 12.2, y 9.5 respectivamente. Las diferencias entre las medias fueron estadísticamente significativas. (p= 0.00006, 0.000002 y 0.03701). Conclusiones: El padecimiento de VPPB del conducto semicircular posterior afecta la calidad en el estilo de vida de las personas. Las maniobras de reposicionamiento son estadísticamente significativas para disminuir la incapacidad generada por el vértigo posicional paroxístico benigno del conducto semicircular posterior por lo que es importante acudir rápidamente al médico especialista cuando se manifiesten los primeros signos y evitar así aumentar la discapacidad total asociada al vértigo. Palabras Clave: Vértigo Posicional Paroxístico (VPPB), otolitos, Dizziness Handycap Inventory (DHI).

Introduction. Benign Paroxysmal Positional Vertigo (BPPV) of the posterior semicircular canal is a chronic disease severely affecting quality of life. Repositioning Maneuvers is a way of relieving it, consisting of a series of sequential exercises of the head into 4 positions. The purpose of the maneuver is to reposition the otoliths from the posterior semicircular canal inside the lobby to the sites where they migrated to stop producing vertigo. Each position has to remain for approximately 30 seconds. The maneuvers have proven to be highly effective in the short term. The results are measurable by means of a questionnaire known as Dizziness Handicap Inventory (DHI). Objectives: To measure the impact of repositioning maneuvers on disability in patients with BPPV of posterior semicircular canal, using the DHI. Methods: A comparative study using T-test for paired samples where each patient is his own control was used in a sample of 20 patients diagnosed with BPPV of posterior semicircular canal were studied and treated with repositioning maneuvers. Results were evaluated by DHI and ran in day 1, day 7 and 30 after Repositioning maneuvers performed. Results: Females are most affected by BPPV in a ratio of approximately 2.1. The degree of disability was measured by the result of DHI, which shows for days 1, 7, and 30 an average of 50.4, 30.4 and 24.2 respectively. The scale with a higher score were days 1 and 7 then showing a marked decreased on day 30. Mean results were the 20, 12.2 and 9.5 respectively. The differences between the means were statistically significant. (P = 0.000062, 0.000002 and 0.037010). Conclusions: BPPV affects the quality of life. Repositioning maneuvers are statistically significant to reduce the disability caused by BPPV of the posterior semicircular canal so, it is important to quickly see a specialist when first signs manifest and that way avoid increasing the total disability associated with vertigo. Keywords: Paroxysmal Positional Vertigo (BPPV), Otolith, Dizziness Handicap Inventory (DHI)

Individual, spatial and inter-sex variation in somatic growth: a study of Piaractus mesopotamicus (Characiformes: Serrasalmidae), a long-distance freshwater Neotropical migratory fish

Growth is a fundamental biological process, driven by multiple endogenous (intra-individual) and exogenous (environmental) factors that maintain individual fitness and population stability. The current study aims to assess whether individual, spatial (headwaters and floodplains) and inter-sex variation occurs in the growth of Piaractus mesopotamicus in the Cuiabá River basin. Samples were collected monthly from July 2006 to July 2007, at two areas in the Cuiabá River basin (headwaters and floodplain). Three growth models (individuals; individuals and sex factors; individuals and areas factors) were developed and compared the fish growth parameters using Akaike information criterion (AIC). The best fit to the length-at-age data was obtained by a model that considered individual variation and sex. The theoretical maximum average length ( L∞ ) was 64.99 cm for females, and 63.23 cm for males. Females showed a growth rate (k) of 0.230 yr-1and males of 0.196 yr-1. Thus, could be concluded that individual variability and sex were the main sources of variation in P. mesopotamicus somatic growth parameters.(AU)

O crescimento é um processo biológico fundamental, impulsionado por múltiplos fatores endógenos (intra-individual) e exógenos (ambientais) que mantém o fitness individual e a estabilidade populacional. Este trabalho tem como objetivo avaliar se ocorre variação individual, espacial (região de cabeceira e planície de inundação) e entre sexo no crescimento de Piaractus mesopotamicus na bacia do rio Cuiabá. Amostragens foram realizadas mensalmente entre julho de 2006 a julho de 2007, em duas áreas da bacia do rio Cuiabá (região de cabeceira e planície de inundação). Três modelos de crescimento (indivíduos, indivíduos e sexo como fator, indivíduos e área como fator) foram elaborados e comparados os parâmetros de crescimentos dos peixes com base no critério de Informação de Akaike (AIC). O melhor ajuste aos dados de comprimento na idade data foi obtido pelo modelo que considerou a variação individual e o sexo. O comprimento médio máximo teórico ( L∞ ) das fêmeas foi 64,99 cm e para os machos 63,23 cm. O coeficiente de crescimento (k) médio foi de 0,230 yr-1 e 0,196 yr-1, respectivamente para fêmeas e machos. Portanto, pode-se concluir que variabilidade individual e sexo foram as principais origem de variação dos parâmetros de crescimento somático de P. mesopotamicus.(AU)

Morphological and biometrical characteristics on otolith of Barbus tauricus Kessler, 1877 on light and scanning electron microscope / Características morfológicas y biométricas de los otolitos de Barbus tauricus Kessler, 1877 bajo microscopio de luz y electrónico de barrido

The otolith morphology, biometry and the relationship between the otolith size and fish length were examined. The weight, length, width, area and perimeter were recorded for each pair of otoliths. The values of form factor (FF), roundness (RD), aspect ratio (AR), circularity (C), rectangularity (R) and elipticity (E) were calculated and the relationships between otolith length (OL) and shape indices were showed with graphics. According to paired t-test results, difference between right and left otoliths was important statistically (P<0.05), except otolith length. It is the first time, the difference of otolith variables were observed not only right and left pairs but also females and males of fish a member of Cyprinidae. While the otolith weight had the lowest coefficient of determination (r2) such as 0.69; 0.59; 0.65, otolith length had the highest 0.80; 0.81; 0.80, for female, male and all specimens, respectively. In addition, SEM images were firstly shown for otoliths of B. tauricus to determine the otolith morphology.

Se examinó la morfología de los otolitos, su biometría y la relación entre el tamaño de ellos y la longitud de los peces. Se registró el peso, longitud, grosor, área y perímetro para cada par de otolitos. Se calcularon y se identificaron en los gráficos los valores de factor de forma, redondez, relación de aspecto, circularidad, rectangularidad, elipticidad y las relaciones entre la longitud del otolito y los índices de la forma. De acuerdo con los resultados, la diferencia entre otolitos derechos e izquierdos fue estadísticamente significativo (P<0,05), excepto la longitud del otolito. Esta es la primera vez que se observa la diferencia de las variables de otolitos, no sólo ente los pares de derecha e izquierda, sino también entre peces hembras y machos. Mientras que el peso de los otolitos tuvo el menor coeficiente de determinación (R2), tales como 0,69; 0,59; 0,65, la longitud de los otolitos presentó un R2 más alto: 0,80; 0,81; 0.80, para hembras, machos y todas las muestras, respectivamente. Además, las imágenes de miscroscopía electrónica de barrido son las primeras en mostrar los otolitos de B. tauricus para determinar la morfología de éstos.

Depressed resilience of bluefin tuna in the western atlantic and age truncation.

Following intense overfishing in the 1970s, the western stock of Atlantic bluefin tuna (Thunnus thynnus) experienced a long period of depressed abundance, which has been attributed to failure of the population to periodically produce large numbers of juveniles, the western stock mixing with the more highly exploited eastern stock (fisheries in the Northeast Atlantic Ocean and Mediterranean Sea), and regime shift in the population's ecosystem resulting in lower replacement rates. To evaluate the presence of relatively strong years of juvenile production, we analyzed age structure from a recent sample of otoliths (ear stones) collected from the western stock (2011-2013, North Carolina, U.S.A., winter fishery). Mixing levels for the recent sample were analyzed using otolith stable isotopes to test whether age structure might be biased through immigration of eastern stock bluefin tuna. Age structure from historical samples collected from United States and Canadian fisheries (1975-1981) was compared with more recent samples (1996-2007) to examine whether demographic changes had occurred to the western stock that might have disrupted juvenile production. Relatively high juvenile production occurred in 2003, 2005, and 2006. Otolith stable isotope analysis showed that these recruitments were mostly of western stock origin. However, these high recruitments were >2-fold less than historical recruitment. We found substantial age truncation in the sampled fisheries. Half the historical sample was >20 years old (mean age = 20.1 [SD 3.7]; skewness = -0.3), whereas <5% of the recent sample was >20 years old (mean age = 13.4 [SD 3.8]; skewness = 1.3). Loss of age structure is consistent with changes in fishing selectivity and trends in the stock assessment used for management. We propose that fishing, as a forcing variable, brought about a threshold shift in the western stock toward lower biomass and production, a shift that emulates the regime shift hypothesis. An abbreviated reproductive life span compromised resilience by reducing the period over which adults spawn and thereby curtailing the stock's ability to sample year-to-year variability in conditions that favor offspring survival (i.e., storage effect). Because recruitment dynamics by the western stock exhibit threshold dynamics, returning it to a higher production state will entail greater reductions in exploitation rates.

Edad y crecimiento del jurel Trachurus murphyi en el Perú

Se determinó la edad y se estimó el crecimiento del jurel Trachurus murphyi Nichols 1920, mediante la lectura y medición de anillos anuales de crecimiento en 977 pares de otolitos de especímenes entre 3 y 71 cm de longitud total colectados dentro del dominio marítimo peruano durante el año 1978 y parte de 1977 y 1979. Se comprobó la validez de las marcas anuales en 50 otolitos con 5 marcas o zonas anuales, y también con el análisis del incremento marginal mensual en 240 otolitos de especímenes entre 35 y 39 cm obtenidos entre julio 1977 y junio 1979. A partir de las medidas de los anillos anuales y sus respectivas tallas retrocalculadas se estimaron los parámetros de crecimiento en longitud y peso de la ecuación de von Bertalanffy: longitud infinita (L∞) =80.77 cm, peso infinito (W∞) = 3744.10 g, coeficiente de crecimiento (k) = 0.155 y edad teórica a la longitud 0 (t0) = -0.356. Se discuten las diferencias y semejanzas con las curvas y parámetros de crecimiento calculados por otros autores, haciendo énfasis en aquéllos cuyos resultados contribuyen a validar los estimados en el presente trabajo. Según los parámetros estimados, el T. murphyi peruano tendría una velocidad de crecimiento mayor que el T. murphyi de más al sur

The age and growth of Jack mackerel Trachurus murphyi Nichols 1920 was determined by the reading and measuring annual growth rings from 977 pairs of otoliths from specimens between 3 and 71 cm total length collected within the Peruvian maritime domain during 1978 and part of 1977 and 1979. The validity of the annual marks was confirmed with 50 otolith with 5 marks or annual zones, and also with the analysis of the monthly marginal increment in 240 otoliths of specimens between 35 and 39 cm obtained from July 1977 to June 1979. From the annual rings measurements and their respective retroestimated sizes, the following parameters of the von Bertalanfy ecuation for growth in length and weight were estimated: infinite length (L∞) = 80.77 cm, infinite weight (W∞) = 3744.10 g, growth coefficient (k) = 0.155, and theoretical age at length 0 (t0) = -0.356. The estimated parameters suggest that the Peruvian T. murphyi has a faster growth rate than the more southern T. murphyi

Crecimiento somático y relación ARN/ADN en estadios juveniles de Eucinostomus argenteus (Pisces: Gerreidae) en dos localidades del Caribe de Venezuela / Somatic growth and RNA/DNA rate of Eucinostomus argenteus (Pisces: Gerreidae) juveniles stages at two localities of the Venezuelan

Somatic growth and RNA/DNA rate of Eucinostomus argenteus (Pisces: Gerreidae) juveniles stages at two localities of the Venezuelan Caribbean. In order to evaluate the association among growth indices of marine fishes at early life stages, the somatic growth rate and physiological conditions of Eucinostomus argenteus were estimated at two Venezuelan North-East zones: Mochima Bay and Cariaco Gulf. The age and somatic growth rate were estimated based on daily growth increments in sagitta otoliths. The physiological conditions were evaluated with proteins concentrations and RNA/DNA rate, which were estimated by spectrofluorometric and fluorometric techniques, respectively, on muscle tissue. Juvenile standard length ranged from 9.80 to 39.20mm from 21 to 73 days of age. At all the study localities there were significant and positive correlations between age, otolith diameter and body size, and fitted to a linear regression model. The values of recent growth rate ranged from 0.178 to 0.418mm day-1, backcalculated growth rate oscillated between 0.295-0.393mm day-1, and RNA/DNA rate ranged from 1.65 to 6.97. Differences were not found between study zones, but there were differences between localities. Despite the fact that there was no correlation between juvenile´s somatic growth and RNA/DNA rates, the reported values suggesting a E. argenteus juvenile’s positive growth in their natural habitat at localities studied. Nevertheless, in some localities values that indicate poor nutritional conditions were registered, which could affect other future demographic rates as survivor and fecundity.

Con la finalidad de evaluar la asociación de índices de crecimiento en estadios tempranos de peces marinos, se estimó la tasa de crecimiento somático y las condiciones fisiológicas de Eucinostomus argenteus en dos zonas del nor-oriente venezolano: Bahía de Mochima y Golfo de Cariaco. La edad y el crecimiento fueron estimados basados en análisis de otolitos sagitta. Las condiciones fisiológicas fueron evaluadas por medio de las concentraciones de proteínas y la relación ARN/ADN, empleando técnicas espectofotométricas y fluorométricas sobre tejido muscular. Las relaciones entre tallas con la edad y el diámetro de los otolitos resultaron positivas, significativas y ajustadas a un modelo de regresión lineal. Los valores de la tasa de crecimiento reciente oscilaron entre 0.178 y 0.418mm día-1, la tasa de crecimiento retrocalculado varió entre 0.295 y 0.393mm día-1, y la tasa ARN/ADN osciló entre 1.65 y 6.97. No se registraron diferencias entre las zonas de estudio, sin embargo se reportaron diferencias entre localidades. A pesar de no encontrarse correlación entre la tasa de crecimiento y la relación ARN/ADN, los valores reportados sugieren crecimiento positivo de los individuos silvestres en las localidades evaluadas. No obstante, ciertas localidades mostraron valores que indican pobres condiciones nutricionales, pudiendo afectarse a futuro otras tasas vitales.

Estudo preliminar da utilização de otólitos de Cynoscion acoupa sobre o processo de neoformação óssea em ratos / Preliminary study of using otoliths of Cynoscion acoupa upon the process of bone regeneration in rats

INTRODUÇÃO: Otólitos são concrescências calcárias presentes no ouvido interno de peixes. Por serem ricos em minerais considerados essenciais ao processo de mineralização óssea sobre uma matriz proteica (otolina), sugere-se que otólitos poderiam funcionar como biominerais. OBJETIVO: Avaliar a capacidade de regeneração de defeitos ósseos tratados com preparado gelatinoso estéril de otólitos. MATERIAL E MÉTODO: O experimento foi realizado com 20 ratos Wistar, distribuídos aleatoriamente em dois grupos, nos quais se realizou defeito ósseo na tíbia, sendo o grupo 1 (G1) experimental, cujas lojas ósseas foram preenchidas com preparado de otólitos, e o grupo 2 (G2) controle, cujas lojas ósseas não receberam tratamento adicional. Os animais foram sacrificados 14 dias após os procedimentos cirúrgicos; as tíbias foram removidas, fixadas em formalina a 10 por cento, descalcificadas em ácido nítrico a 5 por cento e processadas histologicamente. Antes dos sacrifícios, foram coletadas amostras sanguíneas para avaliação das dosagens séricas de cálcio (Ca) e fosfatase alcalina (Alkp). RESULTADOS: As secções histológicas revelaram que o trabeculado ósseo neoformado mostrou-se mais denso e com atividade osteorreabsortiva periosteal menos conspícua no grupo experimental. Entretanto, não demonstraram diferenças estatisticamente significativas na área de neoformação óssea entre G1 (1,9 ± 0,3 mm²) e G2 (1,5 ± 0,4 mm²) (p = 0,0617). Os parâmetros bioquímicos (Ca e Alkp) apresentaram-se dentro dos limites de normalidade. DISCUSSÃO/CONCLUSÃO: Os dados sugerem que os otólitos podem desempenhar papel adjuvante na dinâmica da regeneração óssea.

INTRODUCTION: Otoliths are calcareous concrescences present in the inner ear of fishes. Since they are rich in minerals considered essential to the bone mineralization process on a protein matrix (otolin), it has been suggested that otoliths may work as biominerals. OBJECTIVE: The objective in this study was to analyze the regeneration capacity of bone defects treated with sterile gelatinous otolith preparation. MATERIAL AND METHOD: The experiment was performed with 20 Wistar rats randomized into two groups, in which a bone defect was inflicted in the tibia. In group 1 (experimental), bone cavities were filled with otoliths. In group 2 (control), bone cavities did not receive any additional treatment. The animals were sacrificed 14 days after surgical procedures. The tibias were removed, fixed in formalin at 10 percent, decalcified in nitric acid at 5 percent and histologically processed. Before sacrifice, blood samples were collected to evaluate serum dosage of calcium (Ca2+) and alkaline phosphatase (Alkp). RESULTS: Histological sections revealed that the newly formed trabecular bone was denser and the periosteal reabsorptive activity was less conspicuous in the experimental group. However, there was no statistically significant difference in the area of bone formation between G1 (1.9 ± 0.3 mm²) and G2 (1.5 ± 0.4 mm²) (p = 0.0617). Biochemical (Ca2+ and Alkp) parameters were within normal range. DISCUSSION/CONCLUSION: These data suggest that otoliths may be an adjuvant to the dynamics of bone regeneration.

Formation of ring marks in stocked tilapia juveniles (Oreochromis aureus/O. niloticus) (Perciformes: Cichlidae)

Lake Metztitlán was dried up completely in the spring of 1998 and refilled in August of that year. In the period September-November, two cohorts of 1.6 million juveniles of a tilapia hybrid were stocked (Oreochromis aureus/O. niloticus), and monitored every month for one year. Since the date of birth of these juveniles was known, the analyses focused on whether the ring marks of the scales, sagittae and opercula or the circuli of the scales could be used to age them. The ring marks of the scales and opercula showed great variability, and the sagittae had a significant relationship with length, but it is unclear if at least the first ring mark could be formed at the hatchery and reflect changes in diet and/or tank movements in the fish farm. The circuli had a continuous regular behavior, with a formation rate of 10.38±0.93 and 11.38±0.95 circuli/month for the first and second cohorts, respectively. This proportion was maintained during the study period, and could be of help to calculate an approximate age of juveniles, especially in stocked fish that show multiple ring marks because of manipulation in fish farms and stocking events. Rev. Biol. Trop. 55 (3-4): 1005-1013. Epub 2007 December, 28.

El lago de Metztitlán se secó completamente en la primavera de 1998, inundándose nuevamente en agosto del mismo año para ser repoblado entre septiembre y noviembre con 1.6 millones de jóvenes de un híbrido de tilapia (Oreochromis aureus/O. niloticus) en dos periodos. Ambas cohortes fueron monitoreadas mensualmente durante un año. Debido a que la fecha de nacimiento era conocida, el objetivo del estudio fue evaluar si las marcas anulares de las escamas, las sagittae y los opérculos, o los circuli de las escamas pueden usarse para estimar la edad. Los anillos de las escamas y opérculos mostraron gran variabilidad, mientras que las de las sagittae se relacionaron significativamente con la longitud, sin embargo no quedó claro si al menos el primer anillo podría haber sido formado por cambios en dieta o movimientos en los tanques de la granja de cultivo. Por el contrario los circuli mostraron una formación regular con una tasa de formación de 10.38±0.93 y 11.38±0.95 circuli/mes para la primera y segunda cohortes, respectivamente, proporción que fue mantenida durante el periodo de estudio y que puede ser usada para calcular la edad de los jóvenes, especialmente en organismos que muestran numerosos anillos debido a la manipulación sufrida en las granjas o debido a las "siembras".

Influencia vestibular en la respuesta a la maniobra de Bielschowsky en parálisis del cuarto nervio craneal / Vestibular influence in the response to Bielschowsky maneuver in fourth cranial nerve palsy

Objetivo: Describir en una serie de pacientes con parálisis unilateral del cuarto nervio craneal, la diferencia de la desviación vertical en posición erecta y supina. Material y método: Se incluyeron pacientes con diagnóstico de parálisis del cuarto nervio craneal unilateral, realizando exploración oftalmológica completa así como medición de la desviación con prismas y oclusión alterna en posición erecta y en posición supina realizando la maniobra de Bielschowsky. Resultados: Se exploraron 13 pacientes con el diagnóstico antes mencionado; la mayor parte de ellos presentaron menor desviación vertical en posición supina; así mismo al realizar la maniobra de Bielschowsky, la respuesta en posición supina fue menor que la presentada en posición erecta. Conclusiones: Los reflejos vestíbulo oculares, responsable de la mayor desviación vertical al inclinar la cabeza hacia el lado parético en casos de parálisis del nervio troclear, se atenúan en posición supina. La explicación fisiológica se basa en el control de los movimientos oculares por parte de los otolitos, los cuales reciben estimulación de a cuerdo a su posición en relación a la gravedad; esta observación clínica apoya la explicación propuesta por Bielschowsky sobre la participación del aparato vestibular en uno de los principales signos clínicos de esta entidad.

Purpose. To describe vertical deviation differences in a group of patients with unilateral fourth cranial nerve palsy in erect versus supine position. Methods. We included patients with unilateral fourth cranial nerve palsy who underwent full ophthalmologic exploration and measurement of the vertical deviation with prisms and alternate occlusion in erect and supine position performing Bielschowsky´s test. Results. Thirteen patients were explored; most of them showed less vertical deviation in the supine position, the response to the Bielschowsky´s test was smaller in the supine position than in the erect patient. Conclusion. The vestibulo-ocular reflexes responsible for the larger vertical deviation when tilting the head to the paretic side, are attenuated in the supine position; the physiologic explanation of this phenomenon is based on the otholits role in the control of ocular movements; these receptors are stimulated according to their position in relation to gravity. This clinical observation supports the explanation proposed by Bielschowsky about the role of the vestibular system in one of the main clinical sings of this entity.

La estimación visual de lo que está vertical en alteraciones vestibulares / The subjective visual vertical in vestibular disease

Objective. To assess and compare the accuracy to perceive visual verticality, with and without trunk-head tilt in the frontal plane (30°), in patients with peripheral or central vestibular disease. Methods. Thirty eight patients accepted to participate, 23 with peripheral disease and 15 with central disease. We also evaluated 40 healthy subjects. Subjects were seated facing a screen with an anchored motorized bar (20 cm). They were asked to bring the line to vertical, using a joystick, 10 times while seated upright and 10 times while tilted 30° to each side. An average of the distance from true vertical was calculated to determine the tilt of the visual vertical on each posture. Results. Always, estimations made by healthy subjects were < 2° from true vertical. In patients, in upright posture the largest tilt of the visual vertical was observed in patients with peripheral disease and spontaneous nystagmus. However, in all patients the accuracy to estimate the true vertical decreased when they were evaluated with trunk-head tilt (p < 0.05). In this condition the sensitivity of the test increased from 34 to 85% and the efficacy from 68 to 93% (p < 0.05). Conclusion. Trunk-head tilt in the frontal plane decreases the accuracy of patients with vestibular disease to visually perceive verticality. This finding shows that head-trunk tilt can improve the sensibility and efficacy of this test to assess the vestibular function.

Objetivo. Identificar y comparar la precisión de la estimación visual de lo que está vertical, con y sin inclinación tronco-cefálica en el plano frontal (30°), en pacientes con enfermedad vestibular periférica o central. Métodos. Participaron 38 pacientes con enfermedad vestibular, periférica en 23 y central en 15, además de 40 sujetos sin enfermedad vestibular. Se les instruyó a colocar en posición vertical una barra motorizada de 20 cm, manipulada por control remoto, mientras se encontraban sentados a 30 cm de una pantalla, sin guías visuales. Después de 10 determinaciones con el tronco y la cabeza erguidos y 10 determinación con inclinación tronco-cefálica de 30° a cada lado, se calculó el promedio del error de las estimaciones efectuadas en cada postura. Resultados. En sujetos sin enfermedad vestibular el error de la estimación en cualquier posición fue siempre menor a 2°. En posición erguida, el mayor error en la estimación se observó en pacientes con enfermedad periférica con nistagmus espontáneo. En todos los pacientes el error aumentó significativamente con inclinación tronco-cefálica (ANOVA, p < 0.05), particularmente en aquellos con afección de sistema nervioso central. Al efectuarse la prueba con inclinación tronco-cefálica la sensibilidad de la prueba para identificar a pacientes con enfermedad vestibular aumentó de 34 a 85% y la eficiencia de 68 a 93% (p < 0.05). Conclusión. La inclinación tronco-cefálica en el plano frontal aumenta la desviación de la percepción de lo que está vertical en pacientes con lesión vestibular periférica o central, lo que mejora la utilidad de la prueba para evaluar la función vestibular.

Seleção das estruturas calcificadas para determinação da idade da piracatinga Calophysus macropterus Lichtenstein (Siluriformes: Pimelodidae) na Amazônia Central, Brasil / Selection of calcificated structure for aging of the piracatinga, Calophysus macropterus Lichtenstein (Siluriformes: Pimelodidae) in the Central Amazon, Brazil

O objetivo deste trabalho foi identificar a estrutura calcificada mais adequada para a determinação da idade da piracatinga (Calophysus macropterus). Foram analisados 440 indivíduos procedentes da pesca comercial e experimental do Baixo Solimões. Deste total, foram analisados opérculos, otólitos (asteriscus) e vértebras de uma sub-amostra de 130 indivíduos. Para a observação dos anéis de crescimento nos otólitos, foram testadas duas técnicas de clarificação e quatro técnicas de coloração nas vértebras. A análise das estruturas calcificada demonstrou que os otólitos são estruturas pouco translúcidas e apresentam dificuldades para a observação das marcas de crescimento. Por outro lado os opérculos não apresentaram marcas visíveis de crescimento, e nas vértebras foi observado um padrão nítido e estável de marcação de anéis de crescimento. Portanto, as vértebras foram as estruturas mais adequadas para determinar a idade da piracatinga, além de apresentar uma relação linear significativa entre o raio total das vértebras e o comprimento do peixe (r=0,91; P<0,05). Entre os métodos testados para a visualização dos anéis nas vértebras de peixes teleosteos, a técnica nova a de Hiper-oxidação e Descalcificação Química (HDQ), mostrou ser a melhor. As marcas de crescimentos em vértebras foram validadas utilizando o método de incremento marginal relativo. A piracatinga forma duas marcas de crescimento por ano nas vértebras; o primeiro durante a vazante (agosto) e o segundo durante a enchente (janeiro).

The goal of this study was to identify the best calcified structure for determination of the age of the piracatinga (Calophysus macropterus). A total of 440 specimens from commercial samples and experimental fishing in the Solimões River. Were used for analysis: Opercula, otoliths, and vertebrae were analyzed from a sub sample (n=130). Two clarification techniques were used for visualization of growth rings in the otoliths and four coloration techniques for vertebrae. The otoliths were not translucent and it was very difficult to see the growth rings. The vertebrae were the best calcified structure because the radius of the vertebrae and the length of fish had clear significant linear relationship (r= 0.91; P<0.05) and a clear visualization of the growth rings. Among the techniques used for examining vertebrae of the teleostean fishes, the chemical decalcification, hyper-oxidation technique, was the best to observe the growth rings in the vertebrae. The seasonal rings were validated using relative marginal incremental analysis. Two annual rings are formed in the vertebrae of Calophysus macropterus, being the first during low water (August) and the second during high water season (January). On the vertebrae, a maximum of seven rings were observed.