Using Observed Residual Error Structure Yields the Best Estimates of Individual Growth Parameters

Marcelo Vidal Curiel Bernal EUGENIO ALBERTO ARAGON NORIEGA MIGUEL ANGEL CISNEROS MATA LAURA SANCHEZ VELASCO SYLVIA PATRICIA ADELHEID JIMENEZ ROSENBERG ALEJANDRO FRANCISCO PARES SIERRA (2021, [Artículo])

"Obtaining the best possible estimates of individual growth parameters is essential in studies of physiology, fisheries management, and conservation of natural resources since growth is a key component of population dynamics. In the present work, we use data of an endangered fish species to demonstrate the importance of selecting the right data error structure when fitting growth models in multimodel inference. The totoaba (Totoaba macdonaldi) is a fish species endemic to the Gulf of California increasingly studied in recent times due to a perceived threat of extinction. Previous works estimated individual growth using the von Bertalanffy model assuming a constant variance of length-at-age. Here, we reanalyze the same data under five different variance assumptions to fit the von Bertalanffy and Gompertz models. We found consistent significant differences between the constant and nonconstant error structure scenarios and provide an example of the consequences using the growth performance index _0 to show how using the wrong error structure can produce growth parameter values that can lead to biased conclusions. Based on these results, for totoaba and other related species, we recommend using the observed error structure to obtain the individual growth parameters."

multimodel inference, error structure, totoaba, growth performance BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) FISIOLOGÍA ANIMAL FISIOLOGÍA ANIMAL

Insights into the transboundary stock structure of white seabass, Atractoscion nobilis, along the coast of California and Baja California

Perspectivas sobre la estructura del stock transfronterizo de la corvina blanca, Atractoscion nobilis, a lo largo de la costa de California y de Baja California

ARTURO FAJARDO YAMAMOTO (2023, [Tesis de doctorado])

The white seabass (Atractoscion nobilis) is a transboundary fishery resource that ranges from California, U.S., to Baja California Sur, Mexico, and within the north of the Gulf of California. It has been proposed two stock structure hypotheses that exist across their range in the eastern Pacific. However, still there are important data gaps to fill to understand the stock structure of this species. The aim of this study was to develop more information to understand the Pacific stock structure of the white seabass by (1) enhancing the baseline (catch-effort) information for the Mexican WSB fishery, (2) estimating the size-at-maturity and (3) describe the horizontal movement patterns and habitat utilization of adult WSB. Results suggest that the landings of the Mexican white seabass fishery showed an overall increase over the past 70 years. Landing fluctuations were associated with shifts in contextual factors, such as market changes and geopolitical events. For the past 20 years, the majority of harvest has come from Baja California Sur, with landings concentrated primarily in the fishery offices of Ciudad Constitución, Punta Abreojos, and San Carlos. White seabass females from southern Baja California mature at a size of 72.7 cm, while the males mature at a size of 58 cm. Moreover, regional differences of maturity were estimated where WSB from California matures larger than those from southern Baja California. A connectivity degree of white seabass adult was estimated between the coast of California and the west coast of the Baja California Peninsula. Overall, areas around islands and coastal areas are high-use areas for adult WSB. The Channel Islands, the region off Coronado Islands-Ensenada, the San Quintin region, and the Vizcaino Bay region are essential areas for WSB since different WSB ontogenic stages have been recorded. The spawning (March-September) and none spawning (October-February) seasons for adult WSB have marked differences in habitat utilization. Two migration pathways were estimated: one, a dispersal movement where adult white seabass moved northward to an area around the Channel Islands in California and a southward movement along the coast of the west coast of the Baja California Peninsula where multiple high-use areas were occupied and, second a return movement from north and south areas to a constrained and restricted area off the coast of Tijuana and San Quintin. Considering the information generated in this thesis, we have ...

La corvina blanca (Atractoscion nobilis) es un recurso pesquero transfronterizo que se extiende desde California, EE. UU., hasta Baja California Sur, México, y dentro del norte del Golfo de California. Se han propuesto dos hipótesis que describen la estructura del stock de la corvina blanca a lo largo de su área de distribución en el Pacífico oriental. Sin embargo, aún quedan vacíos en la información biológica-pesquera que nos permita comprender de una manera más robusta la estructura del stock. El objetivo de este estudio fue el desarrollar más información que nos permita comprender la estructura del stock de la corvina blanca que habita el Pacífico mediante (1) la reconstrucción de los desembarques de la pesquería mexicana, (2) la estimación del tamaño de madurez y (3) la descripción de los patrones de movimiento horizontal y el uso de hábitat de la corvina blanca adulta. Los resultados sugieren que los desembarques de la pesquería mexicana de corvina blanca mostraron un aumento en los últimos 70 años. Durante los últimos 20 años, la mayor parte de la captura proviene de Baja California Sur, concentrándose los desembarques en las oficinas pesqueras de Ciudad Constitución, Punta Abreojos y San Carlos. Las hembras de corvina blanca del sur de la Península de Baja California Sur maduran a una talla de 72,7 cm, mientras que los machos lo hacen a una talla de 58 cm. Además, se estimaron diferencias regionales de madurez, siendo que las corvinas blancas de California maduran a una talla mayor que las del sur de la Península de Baja California. Se estimó un cierto grado de conectividad de la corvina blanca adulta entre la costa de California y la costa oeste de la península de Baja California. En general, las áreas alrededor de las islas y las zonas costeras son zonas de alto uso para la corvina blanca adulta. Las islas del Canal, la región frente a las islas Coronado-Ensenada, la región de San Quintín y la región de la bahía Vizcaíno son zonas esenciales para la corvina blanca, ya que se han registrado diferentes fases ontogénicas en dichas zonas. El uso del hábitat de las corvinas blancas adultas durante la temporada de desove (marzo-septiembre) y la no desove (octubre-febrero) fue diferente. Se estimaron dos rutas migratorias: una, con movimientos de dispersión donde la corvina blanca adulta se desplazó hacia el norte alcanzando el área alrededor de las Islas del Canal en California, y un movimiento hacia el sur, a lo largo de la costa del litoral oeste...

White seabass, stock structure, landings reconstruction, size-at-maturity, habitat utilization Corvina blanca, estructura del stock, reconstrucción de desembarques, talla de madurez sexual, uso de hábitat CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS PECES Y FAUNA SILVESTRE DINÁMICA DE LAS POBLACIONES DINÁMICA DE LAS POBLACIONES

Contrasting spatial patterns in active-fire and fire-suppressed mediterranean climate old-growth mixed conifer forests

Danny L. Fry  (2014, [Artículo])

In Mediterranean environments in western North America, historic fire regimes in frequent-fire conifer forests are highly variable both temporally and spatially. This complexity influenced forest structure and spatial patterns, but some of this diversity has been lost due to anthropogenic disruption of ecosystem processes, including fire. Information from reference forest sites can help management efforts to restore forests conditions that may be more resilient to future changes in disturbance regimes and climate. In this study, we characterize tree spatial patterns using four-ha stem maps from four old-growth, Jeffrey pine-mixed conifer forests, two with active-fire regimes in northwestern Mexico and two that experienced fire exclusion in the southern Sierra Nevada. Most of the trees were in patches, averaging six to 11 trees per patch at 0.007 to 0.014 ha-1, and occupied 27-46% of the study areas. Average canopy gap sizes (0.04 ha) covering 11-20% of the area were not significantly different among sites. The putative main effects of fire exclusion were higher densities of single trees in smaller size classes, larger proportion of trees (≥56%) in large patches (≥10 trees), and decreases in spatial complexity. While a homogenization of forest structure has been a typical result from fire exclusion, some similarities in patch, single tree, and gap attributes were maintained at these sites. These within-stand descriptions provide spatially relevant benchmarks from which to manage for structural heterogeneity in frequent-fire forest types.

article, climate, controlled study, ecosystem fire history, forest structure, geographic distribution, geographic mapping, land use, mathematical computing, mathematical model, Mexico, spatial analysis, taiga, United States, comparative study, conife CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA