Genetic Signature of Rapid IHHNV (Infectious Hypodermal and Hematopoietic Necrosis Virus) Expansion in Wild Penaeus Shrimp Populations

Infectious hypodermal and hematopoietic necrosis virus (IHHNV) is a widely distributed single-stranded DNA parvovirus that has been responsible for major losses in wild and farmed penaeid shrimp populations on the northwestern Pacific coast of Mexico since the early 1990's. IHHNV has been considered a slow-evolving, stable virus because shrimp populations in this region have recovered to pre-epizootic levels, and limited nucleotide variation has been found in a small number of IHHNV isolates studied from this region. To gain insight into IHHNV evolutionary and population dynamics, we analyzed IHHNV capsid protein gene sequences from 89 Penaeus shrimp, along with 14 previously published sequences. Using Bayesian coalescent approaches, we calculated a mean rate of nucleotide substitution for IHHNV that was unexpectedly high (1.39×10−4 substitutions/site/year) and comparable to that reported for RNA viruses. We found more genetic diversity than previously reported for IHHNV isolates and highly significant subdivision among the viral populations in Mexican waters. Past changes in effective number of infections that we infer from Bayesian skyline plots closely correspond to IHHNV epizootiological historical records. Given the high evolutionary rate and the observed regional isolation of IHHNV in shrimp populations in the Gulf of California, we suggest regular monitoring of wild and farmed shrimp and restriction of shrimp movement as preventative measures for future viral outbreaks

Multiscale characterization of the sea temperature in an area of abalone banks (Haliotis spp.) at Bahia Asuncion, Baja California Sur, Mexico

The Baja California abalone is one of the most important Mexican fisheries because of its high economic value. Despite strong management efforts, this fishery has faced dramatic fluctuations attributed mainly to overfishing and variability of the marine climate. In this report we analyze sea temperature variability off Bahía Asunción, Baja California Sur (Mexico), at temporal scales that may affect abalone biological processes, such as mortality, reproduction, recruitment, and individual growth rate. Since the analysis is based on different data sources, we conducted a series of correlation analyses to determine the coherence between them. We report the average daily cycle and its variations throughout the year and between years for the period 1997–2000, the seasonal cycle and interannual deviations for the period 1992–2000, the behavior of the decadal scale variability based on annual values for the period 1959–1997, and the long-term trends after analyzing the entire 20th century. Furthermore, we conducted a spectral density analysis to estimate the proportional contribution of each temporal scale to the entire variability signal. Results from the high-frequency variability (daily to interannual) suggest a relationship between temperature and the abalone reproductive cycles, a potential negative effect of the very strong ENSO events on the postlarvae, and a differential effect of temperature on juveniles of different species. Regarding the low-frequency variability (decadal to century), we show that recent years represent a much warmer period compared to previous decades, suggesting a different biological community structure between periods. The spectral density analysis indicates seasonal variability as the major contributor to the regional variability, followed by the interannual (related to ENSO). There is almost no information of the marine climate in this region, particularly in regard to fine and high-resolution observations. This contribution will provide new quantitative elements for studies dealing with the ecology of these coastal productive systems

Modeling winter circulation and particle retention in the Magdalena-Almejas Bay lagoon system (Baja California Sur, Mexico)

Se describe la circulación y el transporte pasivo de partículas en las inmediaciones del sistema lagunar Bahía Magdalena- Almejas mediante un modelo lineal de circulación en el dominio de la frecuencia con el que se obtuvieron los campos básicos de flujo. El modelo está forzado por mareas, marea residual, viento medio, viento periódico para simular el efecto de la brisa marina y una simulación aproximada del efecto de la Corriente de California. Se realizaron dos experimentos principales, uno enfocado a detectar zonas de retención en el interior del sistema lagunar, y el segundo para observar el intercambio de partículas entre el sistema y el océano abierto adyacente. Se encontró que las partículas sembradas en el sistema tienden a quedarse dentro y concentrarse en regiones particulares que se correspondieron con la distribución real de bancos pesqueros de recursos bentónicos y, en segundo término, que durante condiciones poco comunes de viento se pueden presentar intrusiones importantes de partículas de la plataforma continental al interior del sistema lagunar. Los resultados son de importancia para el estudio de la zona en general, y particularmente para la modelación y desarrollo de pronósticos de procesos de deriva larval de recursos pesqueros importantes. We describe circulation and passive particle transport in the Magdalena-Almejas Bay lagoon system through a linear circulation model in the frequency domain to obtain basic flux fields. The model is forced by tides, residual tides, mean wind speed, periodic winds (to simulate sea breeze), and an approximation of advection in the California Current. Two main experiments were performed: one to detect retention zones within the lagoon system and another to evaluate particle exchange between the lagoon system and the open ocean. We found that particles seeded within the system tend to remain inside and concentrate in restricted areas that correspond to the real distribution of benthic fish and that, under rare wind conditions, masses of particles seeded on the continental shelf could enter the lagoon system. The results are relevant for the general study of the system and for modeling and developing forecasts of the larval drift of important fish resources

The Gulf of Tehuantepec and adjacent areas: spatial and temporal variation of satellite-derived photosynthetic pigments

Photosynthetic pigment concentrations retrieved from data generated from 1978 to 1986 by the sensor Coastal Zane Color Scanner were used to describe the seasonal and interannual variation of phytoplankton biomass of the Gulf of Tehuantepec and adjacent areas. The pigment concentrations 0.3 mg m–3 and higher were considered as an index of productive waters. Its spatial coverage shows coastal upwelling in the gulfs of Tehuantepec and Papagayo (in the eastern region of the study area) between October and April. upwelling at the Costa Rica dome during summer. and the transient effect of mixing by tropical storms from July to October throughout the study area. Upwelling events in Tehuantepec and Central America are not synchronous. The region west of the Gulf of Tehuantepec is oligotrophic most of the time (less than 0.2 mg m–3). The most evident interannual variation was the effect of El Niño 1982–1983, with very low pigment concentrations associated with a deep thermocline in the whole study area. Also, there was an anti-El Niño event in 1985 in the eastern region, with high phytoplankton biomass concentrations associated with a shallow thermoclin

Updated checklist and analysis of completeness of the marine fish fauna of Isla del Coco, Pacific of Costa Rica

Isla del Coco, Costa Rica, is one of the five groups of oceanic islands of the Eastern Tropical Pacific (ETP), and is considered one of the most diverse. Since the mid-19th century, it has been the target of a number of scientific research expeditions that have produced specimen collections which are housed in natural history museums around the world. The fish assemblage of Isla del Coco is considered one of the most speciose and best documented group of marine organisms of the island. Despite this, recent work has resulted in a need to update the checklist for this important group. We performed a completeness analysis of the ichthyofauna of Isla del Coco based on scientific publications and reports of expeditions, specimens in foreign and national collections, and field surveys. We confirmed the presence of 514 species of marine fishes, representing an increase of approximately 23 % compared to what was previously reported. From a habitat perspective, 58 % of this assemblage is typically reef fishes, while the remaining 42 % are deep-water, and pelagic species. The average expected reef fish species richness is 318.2 ± 7.3, suggesting that the local inventory represents 93.7 % of the expected total richness. Our updated list and greater number of species has particular relevance to the conservation efforts at Isla del Coco, since current conservation efforts are protecting at least 50 % of ETP fish species and about 40 % of Costa Rica’s Pacific fish species.Fonds Français pour l’Environnement Mondial/[]/FFEM/FranciaConsejo Nacional de Rectores de las Universidades Públicas de Costa Rica/[]/CONARE/Costa RicaUniversidad de Costa/[]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de BiologíaUCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Zootecni