Reproduction in the protogynous black grouper Mexico (Mycteroperca bonaci (Poey)) from the southern Gulf of Mexico

An analysis was made of sexual pattern, spawning season, sizes at sexual maturation, and sex change in black grouper (Mycteroperca bonaci) from the southern Gulf of Mexico. Samples were taken between 1996 and 2000, from industrial and small-craft commercial fi sheries, in offshore and inshore waters of the continental shelf of the Yucatan Peninsula (Campeche Bank), including the shallow waters of National Marine Park Alacranes Reef. For all collected specimens (n=1229), sex and maturation condition were determined by histological analysis of the gonads. The offshore sample consisted of 75.1% females, 24.3% males, and 0.6% transitional-stage fish. All individuals collected from inshore waters were females. Gonadal structure and population structure characteristics for Campeche Bank black grouper were consistent with the characteristics of monandric protogynous hermaphrodism for a serranid fish. Sexually active males and females were observed year-round, although ripening females, with stage-III, -IV, and -V vitellogenic oocytes in the ovaries, dominated in samples taken between December and March. In addition, peak occurrence of ripe-running females with hyaline oocytes or postovulatory follicles (or both) in the ovaries was recorded in January and February. A few precocious females began spawning in October and November, and others were still in spawning condition in May and June. Fifty percent maturity of females was attained at 72.1 cm fork length (FL). Median size at sexual inversion was 103.3 cm FL, and 50% of the females measuring 111.4 cm FL had transformed into males. The southern Gulf of Mexico grouper fishery was considered deteriorated and lacked a well-defined management strategy. Results of the present study provide helpful information on black grouper reproduction in this area and could help Mexican authorities choose appropriate management strategies for this fishery, such as minimum size limit, closed fishing season, and protection of spawning aggregations

Estudio de las ferias agrpecuarias, caso feria de la parroquia Cumbe y propuestas para su mejoramiento

EconomistaCuenc

Potential Impact of Climate Change on Fish Reproductive Phenology: A Case Study in Gonochoric and Hermaphrodite Commercially Important Species from the Southern Gulf of Mexico

In tropical regions, temperature is the fundamental environmental factor controlling the reproduction-related physiological activities of fish. Tropical fish are particularly sensitive to climate change since they develop in a relatively stable thermal environment. A review was done to assess the potential effect of temperature rise on reproduction and population structure in the commercially important hermaphrodite grouper and wrasse species, and in gonochoric snapper species in the southern Gulf of Mexico. Temperature increase can disturb the aromatase synthesis and/or activity, which can affect the reproductive cycle and sexual differentiation in all studied species and the sexual inversion process in sequential hermaphrodites. Moreover, a mistiming or discontinuity in spawning seasonality could occur, with an alteration in the sex ratio in favor of males and a consequent reduction in populations’ fecundity. Furthermore, if the level of fishing exploitation enhances species’ sensitivity to environmental changes, then the stock of red grouper Epinephelus morio would be more affected by temperature increases than other species because it is the only fish population in the Campeche Bank currently assessed as overexploited

Growth stanzas in an Epinephelidae-Lutjanidae complex: considerations to length-weight relationships

Growth stanzas or abrupt changes in growth rates are present throughout the life span of fish. Identifying growth stanzas will help to adequately described growth taking into account that fishes are indeterminate growers. In this study, we used length-weight (L-W) relationships to analyze the growth stanzas in the Grouper-Snapper complex of Southern Gulf of Mexico. For this, the type of sexuality, sex and different sexual maturity phase were considered in the analyses of three species of gonochoric Snappers (Lutjanidae) and six species of protogynous hermaphrodite Groupers (Epinephelidae). Welch ANOVA tests were carried out to determine the existence of differences in length and weight between juveniles and adults per sex. According to the observed differences, L-W relationship parameters (a and b), standard error (SE b) and coefficients of determination (R2) were calculated for all species separately by sex and sexual maturity phase. Snappers’ juvenile-females b-value ranged for 2.44-2.77, juvenile-males from 2.16-2.94, adult-females from 2.63-2.80 and adult-males form 2.63-2.98. Groupers’ b-value ranged for juvenile-females 2.66-3.20, adult-females from 2.73-3.31 and for adult-males 2.93-3.29. For each relationship b-value was t-tested (t-Student) to explore differences from the allometric coefficient (b=3), which indicated changes in body form. Hypothesis test, for regression slopes (b) between Snappers’ juvenile-females vs. adult-females and juvenile-males vs. adult-males and Groupers’ juvenile-females vs. adult-females and adult-females vs. adult-males, indicated different growth stanzas related to gonadal development for Snappers, and to gonadal development and sex change in Groupers. The identification of growth stanzas is crucial to avoid an overestimation or misleading growth rate which is used in fisheries management to establish some target reference points, such as maximum sustainable yield or yield-per-recruit

Modelo de Gestión Integral de Bienestar (GESIB) a través de la herramienta de segmentación

El presente trabajo de investigación fue planteado bajo el análisis de una problemática que enfrentan las organizaciones en la actualidad, no sólo en el Perú sino en el mundo entero: El problema de la retención de colaboradores y la alta rotación de personal que existe en las organizaciones. Existen diversos motivos que llevan a enfrentar esta problemática, principalmente en países con economías en expansión y pujantes como es la peruana. Debido a esta situación nos interesamos en replantear las políticas actuales de retención del talento en las organizaciones y desarrollar un modelo que nos ayude a gestionar el bienestar de los colaboradores pero teniendo como base el diseño y aplicación de una adecuada herramienta de segmentación. Esto consideramos, ayudará no sólo a disminuir los índices de rotación en las organizaciones sino también a incrementar los niveles de motivación y mejorar el clima laboral a favor de los colaboradores, así como también, a gestionar de forma más eficiente el presupuesto designado para tales fines. Nuestro objetivo es proponer un Modelo de Gestión Integral de Bienestar - GESIB a través de la herramienta de Segmentación. Nos apoyamos en una herramienta inicialmente creada con el fin de estudiar y dividir mercados y clientes, ya que la segmentación es una herramienta básica del Marketing, y logramos adecuarla para un uso dirigido a organizaciones y colaboradores. GESIB a través de la herramienta de Segmentación y creemos que el éxito de este proyecto y del modelo radica en segmentar a las organizaciones de acuerdo a los siguientes puntos: Buscar la homogeneidad de los grupos formados para que éstos cuenten con características similares y equiparables, así como conocer a profundidad a nuestra población (colaboradores) y asimismo, conocer en qué grupo se ubica cada colaborador. Finalmente planteamos establecer beneficios que puedan ajustarse a las diferencias de cada grupo identificado. Nuestra investigación explica en primer lugar en su marco teórico la problemática actual en la que se encuentran las organizaciones, analizando el problema de la rotación y lo importante de la conciliación entre la vida laboral y la familiar. En segundo lugar pasamos a proponer el modelo desarrollado que cuenta con cinco fases que hemos identificado de la siguiente manera: Conociendo, Descifrando, Dibujando, Actuando y Acompañando Finalmente planteamos una serie de conclusiones y recomendaciones que consideramos nos permitirán cerrar adecuadamente las ideas expuestas, sentar líneas de acción para la correcta aplicación de nuestro Modelo de Gestión Integral del Bienestar - GESIB y contar con lineamientos clave para promover su evolución en el tiempo

Assessing the Speciation of <i>Lutjanus campechanus</i> and <i>Lutjanus purpureus</i> through Otolith Shape and Genetic Analyses

Based on their morphological and genetic similarity, several studies have proposed that Lutjanus campechanus and Lutjanus purpureus are the same species, but there is no confirmed consensus yet. A population-based study concerning otolith shape and genetic analyses was used to evaluate if L. campechanus and L. purpureus are the same species. Samples were collected from populations in the southwestern Gulf of Mexico and the Venezuelan Caribbean. Otolith shape was evaluated by traditional and outline-based geometric morphometrics. Genetic characterization was performed by sequencing the mtDNA control region and intron 8 of the nuclear gene FASD2. The otolith shape analysis did not indicate differences between species. A nested PERMANOVA identified differences in otolith shape for the nested population factor (fishing area) in morphometrics and shape indexes (p = 0.001) and otolith contour (WLT4 anterior zone, p = 0.005 and WLT4 posterodorsal zone, p = 0.002). An AMOVA found the genetic variation between geographic regions to be 10%, while intrapopulation variation was 90%. Network analysis identified an important connection between haplotypes from different regions. A phylogenetic analysis identified a monophyletic group formed by L. campechanus and L. purpureus, suggesting insufficient evolutionary distances between them. Both otolith shape and molecular analyses identified differences, not between the L. campechanus and L. purpureus species, but among their populations, suggesting that western Atlantic red snappers are experiencing a speciation process