A new pathology in the red abalone Haliotis rufescens (Mollusca: Gastropoda) cultured in Baja California, Mexico, associated with macro-crystal inclusions in gonadal tissue

A new severe pathological alteration in the gonadic tissue of red abalone was observed, which compromises reproduction of affected organisms. The alteration is related to the presence of numerous extracellularmacro-crystal inclusions (Mci) reaching up to 300 ?m in size. These Mci may be surrounded by hemocytes, cellular debris, and deposition of fibroblasts. Moreover, hypertrophy of the nuclei of cells in the topgerminal epithelium and presence of brown cells in trabeculae were observed. The normal architecture of the tissue looks entirely altered and destroyed in some cases. No gonadal development was observed.The chemical nature of the Mci is unknown, but it is possibly related to inorganic toxic compounds. No previous records of similar alterations in abalone are known to exist. This record could help determine if this pathology has been observed in other abalone culture areas in the world, its possible origin, and if control is necessary

Early Gametogenesis of Kumamoto oyster (Crassostrea sikamea)

The Kumamoto oyster, Crassostrea sikamea, starts gametogenesis as young as 71 days old from spawning (35 days from postsettlement) with a mean shell height of 3.0 mm. This information constitutes a new record in age-size for gametogenesis in oysters for commercial importance and adds another biological difference comparing this species with the Pacific oyster Crassostrea gigas

Mass Mortality of Cultivated Northern Bluefin Tuna Thunnus thynnus orientalis Associated With Chattonella Species in Baja California, Mexico

In 2016 a mass mortality period (MMP) of cage cultured tuna occurred in the northwest coast of Baja California, Mexico. Nine die-offs occurred from May 31st to August 2nd in Todos Santos Bay, Salsipuedes Bay and Coronado Islands. The organisms were disoriented, gasping, swimming erratically, and died hours after these signs were detected. Necropsies and histopathological analyses were performed on dead organisms. Abundant mucus and congestion was observed in the gills. Histopathological analysis of the gills showed hyperplasia, fusion of gill filaments and lamellae, telangiectasia, edemas, increased numbers of mucus cells, and in some cases severe hemorrhage. Water samples were analyzed and a sampling campaign was implemented in some cultivation areas to evaluate the presence of ichthyotoxic microalgae. Chattonella spp. (mainly C. cf. marina) were detected in the water column during the MMP. At the end of May abundances of 5 × 103 cells L−1 were detected in sea surface samples and Chattonella spp. represented ~20% of the microphytoplankton community. Abundance of these species at surface increased to 33 × 103 cells L−1 in June and represented 85% of the phytoplankton community. No other environmental stressful variables were detected during the MMP. The presence of Chattonella spp. in the water column explains the dead of the tuna since behavior, necropsies, and histopathological analyses of the gills indicate a severe reaction to an environmental noxa that could be related to the characteristic toxic effect of these species. Before the MMP, ichthyotoxic species have not been reported in the phytoplankton community of the region. Accumulation of Chattonella spp. was probably associated with abnormally high temperatures present during the two previous years before the MMP. Surface temperature anomalies of 3°C were registered during 2015. Mesoscale oceanographic and atmospheric phenomena brought the environmental conditions for a change in the phytoplankton community in the region. Phytoplankton biomass was low and associated with a decrease in the abundance of diatoms and dinoflagellates. The absence of diatoms together with upwelling events followed by stratification before the MMP probably favored the accumulation of Chattonella spp. that affected importantly tuna ranching activities in Northwest Baja California

Estudio comparativo del zooplancton (biomasa y composición) en dos bahías del Mar Caribe Mexicano

Existen diferencias notables en biomasa, composición y distribución del zooplancton, entre las bahías de la Ascensión y de Chetumal, en el· litoral oriental de la Península de Yucatán. La de Chetumal representa un sistema heterogéneo desde el punto de vista hidrológico y la comunidad zooplánctica local está representada básicamente por especies eurihalinas; las larvas de peces y decápodos son un componente importante del zooplancton local; esto indica que esta bahía es propicia para la crianza de estas especies. Sin embargo, es probable que la mayor parte de las larvas sean exportadas o bien, emigren del sistema a partir de sUs etapas juveniles o autónomas. El aislamiento de la influencia marina y la baja energía interna restringen la productividad y riqueza faunística de la Bahía de Chetumal. La Bahía de la Ascensión es un sistema hidrológicamente más homogéneo, con mayor influencia marina; su fauna zooplánctica local es más diversa y abundante, yes probable que la emigración de larvas de peces y de decápodos sea menos intensa que en el caso de la Bahía de Chetumal.Strong differences were observed in zooplankton biomass, composítion and distribution in Chetumal and Ascension bays, eastern coast of the Yucatan Península, Mexico. Chetumal Bay is an hydrologically heterogeneous system and the local zooplanktic cornmunity is represented mainly by eurihaline elements. Fish and decapod larvae are relevant eonstituents of the local zooplankton, suggesting a significant breeding area. However, mos! of these larvae migrate passively or actively when reaching juvenile, autonomous stages. The isolation from (he influence of marine water and the internal low energy restríet both productivity and faunistic diversity in Chetumal. Ascensión Bay is, hydrologically, a more homogeneous system, with higher marine input. Its local zooplanktic fauna is more diverse and abundant. Probably, the passive migration of fish and decapod larvae is lower than in Chetuma

Variación espacio-temporal de la biomasa de zooplancton en un sistema estuarino del Caribe Occidental durante dos ciclos anuales

The bay of Chetumal, in the Western Caribbean, is regarded as an uniformly hypohaline and oligotrophic system. In order to define if the zooplankton biomass shows a homogeneous behavior in this coastal system we analyzed the spatio-temporal variation of this parameter (wet weight: mg m-3) during two years (1996, 1997). During 1996, the average annual biomass (11.56 mg m-3) was significantly lower than that recorded during 1997 (16.18 mg m-3). Slightly lower biomass values were observed in northerlies during both years, followed by dry and wet periods, thus suggesting seasonality in the dynamics of this factor in the zooplankton community. Monthly variations were also considerable and suggest that important changes could also be occurring at scales smaller than the seasonal or interannual. Between 45 and 51% of the biomass in 1996 and 1997 was distributed at the outermost and more saline stations of the bay regardless of the season. The high primary production usually related to the inner zone of the bay was not reflected in the zooplankton biomass; this was explained by local distributional restrictions of the resident herbivorous zooplankton and possibly to hypoxia related to local eutrophication. The interannual differences, with higher biomass, temperature, and salinity found in 1997 and also the weak seasonality of that year could be related to the regional effect of El Niño 1997-98. The zooplankton biomass in the bay was relatively low year-round regardless of the season; this was attributed to its low internal hydrographic energy, scarce aquatic vegetation, and to its isolation from the marine influence.La Bahía de Chetumal, en el Caribe Occidental es considerada uniformemente hiposalina y oligotrófica. Para definir si la biomasa de zooplancton muestra un comportamiento homogéneo en este sistema costero se analizó la variación temporal y espacial de este parámetro (peso húmedo: mg m-3) durante dos ciclos anuales (1996, 1997). Se obtuvieron muestras bimensuales en las épocas de nortes, secas y lluvias. Durante 1996, la biomasa anual promedio (11,56 mg m-3) fue significativamente menor a la de 1997 (16,18 mg m-3). Se observaron biomasas ligeramente mayores durante nortes en ambos años, seguidas por secas y lluvias, lo que sugiere una estacionalidad en el comportamiento de este factor de la comunidad del zooplancton. Las variaciones mensuales también fueron considerables y sugieren que podría haber cambios importantes a escalas menores a la estacional o interanual. Entre el 45 y 51% de la biomasa en 1996 y 1997 se distribuyó en las localidades más externas y salinas de la bahía independientemente de la época. La alta producción primaria que usualmente se asocia a la zona interna de la bahía no se reflejó en la biomasa del zooplancton, lo que se atribuyó a las limitaciones en la distribución local de los herbívoros del zooplancton residente y posiblemente a la hipoxia relacionada con eutrofización local. Las diferencias interanuales, con mayores valores de biomasa, temperaturas y salinidades en 1997, así como la débil estacionalidad de ese año (nortes) podrían estar asociadas con el efecto regional de El Niño 1997-1998. La biomasa de zooplancton en la bahía fue relativamente baja durante todo el año, independientemente de las épocas climáticas, lo que se atribuyó a su baja energía hidrográfica interna, su escasa vegetación acuática y a su aislamiento de la influencia marina

Histopathology of cultured juvenile Totoaba macdonaldi associated with bacterial isolates molecularly identified as Vibrio spp. during a temperature increase event

Totoaba macdonaldi is an endangered species of croaker endemic to the Gulf of California, Mexico. This species has been cultured for the repopulation of wild stocks and commercialization at the Wildlife Management and Conservation Unit for the culture of T. macdonaldi at the Universidad Autónoma de Baja California, Mexico. A mortality episode was observed in 50 day-old juveniles, that coincided with an increase of temperature from 16 to 25.5˚C that affected the aquaculture facility. Histopathological and bacteriological analysis of survivor fishes were conducted to investigate the possible causes of mortality. Gill damage including severe congestion in gill filaments, necrosis, and epithelial dissociation of lamellae were observed. Moreover, epidermal, hypodermic necrosis, as well as diffuse bacterial colonization of the dermis was detected. Severe congestion and hemolysis were detected in the heart’s atrium and hepatic portal vessels. From the skin lesions, eight colonies of bacteria were isolated, these corresponded to four species of genus Vibrio, tentatively identified by partial sequence of the 16S rRNA gene as Vibrio harveyi, V. rotiferianus, V. brasilensis and V. shilonii. From them, V. harveyi corresponded to 4 of the 8 isolates and was found in all moribund fishes. Characteristics of the tissue alterations related with these opportunistic Vibrio spp. suggest an acute mortality event favoured by a temperature increase. This is the first record of the histopathology of T. macdonaldi juveniles that suffered an unusual mortality event under an increase of temperature in cultured conditions associated with Vibrio spp.Totoaba macdonaldi es una especie de corvina en peligro de extinción endémica del Golfo de California, México. Esta especie ha sido cultivada para el repoblamiento de stocks silvestres y comercialización en la Unidad de Manejo y Conservación de Vida Silvestre para el cultivo de T. macdonaldi de la Universidad Autónoma de Baja California, México. Se observó un episodio de mortalidad en juveniles de 50 días de edad, que coincidió con un aumento de temperatura de 16 a 25,5˚C que afectó a la instalación acuícola. Se realizaron análisis histopatológicos y bacteriológicos de los peces sobrevivientes para investigar las posibles causas de mortalidad. Se observaron daños en las branquias, incluida una congestión severa en los filamentos branquiales, necrosis y disociación epitelial de las laminillas. Además, se detectó necrosis epidérmica e hipodérmica, así como colonización bacteriana difusa de la dermis. Se detectaron congestión severa y hemólisis en la aurícula del corazón y vasos portales hepáticos. De las lesiones cutáneas se aislaron ocho colonias de bacterias, correspondientes a cuatro especies del género Vibrio, identificadas tentativamente por secuenciación parcial del gen 16S rRNA como Vibrio harveyi, V. rotiferianus, V. brasilensis y V. shilonii. De ellos, V. harveyi correspondió a 4 de los 8 aislamientos y se encontró en todos los peces moribundos. Las características de las alteraciones tisulares relacionadas con estos Vibrio spp. oportunistas, sugieren la ocurrencia de un evento de mortalidad aguda favorecido por un aumento de la temperatura. Este es el primer registro de la histopatología de juveniles de T. macdonaldi que sufrieron un evento inusual de mortalidad ante un aumento de temperatura en condiciones de cultivo asociado con Vibrio spp

Histopathology of cultured juvenile Totoaba macdonaldi associated with bacterial isolates molecularly identified as Vibrio spp. during a temperature increase event

ABSTRACT | Totoaba macdonaldi is an endangered species of croaker endemic to the Gulf of California, Mexico. This species has been cultured for the repopulation of wild stocks and commercialization at the Wildlife Management and Conservation Unit for the culture of T. macdonaldi at the Universidad Autónoma de Baja California, Mexico. A mortality episode was observed in 50 day-old juveniles, that coincided with an increase of temperature from 16 to 25.5˚C that affected the aquaculture facility. Histopathological and bacteriological analysis of survivor fishes were conducted to investigate the possible causes of mortality. Gill damage including severe congestion in gill filaments, necrosis, and epithelial dissociation of lamellae were observed. Moreover, epidermal, hypodermic necrosis, as well as diffuse bacterial colonization of the dermis was detected. Severe congestion and hemolysis were detected in the heart’s atrium and hepatic portal vessels. From the skin lesions, eight colonies of bacteria were isolated, these corresponded to four species of genus Vibrio, tentatively identified by partial sequence of the 16S rRNA gene as Vibrio harveyi, V. rotiferianus, V. brasilensis and V. shilonii. From them, V. harveyi corresponded to 4 of the 8 isolates and was found in all moribund fishes. Characteristics of the tissue alterations related with these opportunistic Vibrio spp. suggest an acute mortality event favoured by a temperature increase. This is the first record of the histopathology of T. macdonaldi juveniles that suffered an unusual mortality event under an increase of temperature in cultured conditions associated with Vibrio spp. RESUMEN | Totoaba macdonaldi es una especie de corvina en peligro de extinción endémica del Golfo de California, México. Esta especie ha sido cultivada para el repoblamiento de stocks silvestres y comercialización en la Unidad de Manejo y Conservación de Vida Silvestre para el cultivo de T. macdonaldi de la Universidad Autónoma de Baja California, México. Se observó un episodio de mortalidad en juveniles de 50 días de edad, que coincidió con un aumento de temperatura de 16 a 25,5˚C que afectó a la instalación acuícola. Se realizaron análisis histopatológicos y bacteriológicos de los peces sobrevivientes para investigar las posibles causas de mortalidad. Se observaron daños en las branquias, incluida una congestión severa en los filamentos branquiales, necrosis y disociación epitelial de las laminillas. Además, se detectó necrosis epidérmica e hipodérmica, así como colonización bacteriana difusa de la dermis. Se detectaron congestión severa y hemólisis en la aurícula del corazón y vasos portales hepáticos. De las lesiones cutáneas se aislaron ocho colonias de bacterias, correspondientes a cuatro especies del género Vibrio, identificadas tentativamente por secuenciación parcial del gen 16S rRNA como Vibrio harveyi, V. rotiferianus, V. brasilensis y V. shilonii. De ellos, V. harveyi correspondió a 4 de los 8 aislamientos y se encontró en todos los peces moribundos. Las características de las alteraciones tisulares relacionadas con estos Vibrio spp. oportunistas, sugieren la ocurrencia de un evento de mortalidad aguda favorecido por un aumento de la temperatura. Este es el primer registro de la histopatología de juveniles de T. macdonaldi que sufrieron un evento inusual de mortalidad ante un aumento de temperatura en condiciones de cultivo asociado con Vibrio spp

Optimizing surveillance for early disease detection: Expert guidance for Ostreid herpesvirus surveillance design and system sensitivity calculation

To keep pace with rising opportunities for disease emergence and spread, surveillance in aquaculture must enable the early detection of both known and new pathogens. Conventional surveillance systems (designed to provide proof of disease freedom) may not support detection outside of periodic sampling windows, leaving substantial blind spots to pathogens that emerge in other times and places. To address this problem, we organized an expert panel to envision optimal systems for early disease detection, focusing on Ostreid herpesvirus 1 (OsHV-1), a pathogen of panzootic consequence to oyster industries. The panel followed an integrative group process to identify and weight surveillance system traits perceived as critical to the early detection of OsHV-1. Results offer a road map with fourteen factors to consider when building surveillance systems geared to early detection; factor weights can be used by planners and analysts to compare the relative value of different designs or enhancements. The results were also used to build a simple, but replicable, model estimating the system sensitivity (SSe) of observational surveillance and, in turn, the confidence in disease freedom that negative reporting can provide. Findings suggest that optimally designed observational systems can contribute substantially to both early detection and disease freedom confidence. In contrast, active surveillance as a singular system is likely insufficient for early detection. The strongest systems combined active with observational surveillance and engaged joint industry and government involvement: results suggest that effective partnerships can generate highly sensitive systems, whereas ineffective partnerships may seriously erode early detection capability. Given the costs of routine testing, and the value (via averted losses) of early detection, we conclude that observational surveillance is an important and potentially very effective tool for health management and disease prevention on oyster farms, but one that demands careful planning and participation. This evaluation centered on OsHV-1 detection in farmed oyster populations. However, many of the features likely generalize to other pathogens and settings, with the important caveat that the pathogens need to manifest via morbidity or mortality events in the species, life stages and environments under observation

Multigenetic characterization of ‘Candidatus Xenohaliotis californiensis’

Cicala, Francesco, Moore, James D., Cáceres-Martínez, Jorge, Del Río-Portilla, Miguel A., Hernández-Rodríguez, Mónica, Vásquez-Yeomans, Rebeca, Rocha-Olivares, Axayácatl (2017): Multigenetic characterization of 'Candidatus Xenohaliotis californiensis'. International Journal of Systematic and Evolutionary Microbiology 67 (1): 42-49, DOI: 10.1099/ijsem.0.001563, URL: http://dx.doi.org/10.1099/ijsem.0.00156