Papers by Ramiro Castillo
Boletin Instituto del Mar del Perú
El 2021 se realizaron dos cruceros de Evaluación Hidroacústica de Recursos Pelágicos en toda la c... more El 2021 se realizaron dos cruceros de Evaluación Hidroacústica de Recursos Pelágicos en toda la costa peruana, teniendo como apoyo de investigación embarcaciones industriales de la Sociedad Nacional de Pesquería (SNP). El primer crucero 2102-07, se efectuó del 17 de febrero al 01 de abril, completado del 19 de junio al 13 de julio, el segundo crucero 2109-11 fue del 22 de setiembre al 03 de noviembre 2021. En este artículo se presenta la distribución y biomasa de la anchoveta, así como del: jurel, caballa, samasa, bagre, munida, pota y vinciguerria en la Región Norte del Sistema de la Corriente de Humboldt (RNSCH). Los resultados mostraron que la anchoveta es la especie de mayor abundancia, su población se encontró saludable, favorecida por las condiciones oceanográficas ligeramente frías a neutras, manteniendo su comportamiento estacional; en el crucero 2102-07 se encontró hasta 80 mn de la costa con altas concentraciones y biomasa de 12,03 millones de toneladas; mientras que, en e...
Boletin Instituto Del Mar Del Peru, 2000
1. Understanding the ecological processes that underpin species distribution patterns is a fundam... more 1. Understanding the ecological processes that underpin species distribution patterns is a fundamental goal in spatial ecology. However, developing predictive models of habitat use is challenging for species that forage in marine environments, as both predators and prey are often highly mobile and difficult to monitor. Consequently, few studies have developed resource selection functions for marine predators based directly on the abundance and distribution of their prey. 2. We analysed contemporaneous data on the diving locations of two seabird species, the shallow-diving Peruvian Booby (Sula variegata) and deeper diving Guanay Cormorant (Phalacrocorax bougainvilliorum), and the abundance and depth distribution of their main prey, Peruvian anchoveta (Engraulis ringens). Based on this unique data set, we developed resource selection functions to test the hypothesis that the probability of seabird diving behaviour at a given location is a function of the relative abundance of prey in the upper water column. 3. For both species, we show that the probability of diving behaviour is mostly explained by the distribution of prey at shallow depths. While the probability of diving behaviour increases sharply with prey abundance at relatively low levels of abundance, support for including abundance in addition to the depth distribution of prey is weak, suggesting that prey abundance was not a major factor determining the location of diving behaviour during the study period. 4. The study thus highlights the importance of the depth distribution of prey for two species of seabird with different diving capabilities. The results complement previous research that points towards the importance of oceanographic processes that enhance the accessibility of prey to seabirds. The implications are that locations where prey is predictably found at accessible depths may be more important for surface foragers, such as seabirds, than locations where prey is predictably abundant. 5. Analysis of the relative importance of abundance and accessibility is essential for the design and evaluation of effective management responses to reduced prey availability for seabirds and other top predators in marine systems
Trends in spatio-temporal distribution of Peruvian anchovy and other small pelagic fish biomass from
Boletín de Investigaciones Marinas y Costeras
The present study determined the distribution and biomass of the Peruvian anchovy and pelagic red... more The present study determined the distribution and biomass of the Peruvian anchovy and pelagic red squat lobster related to the oceanographic characteristics in the marine protected area of the Paracas National Reserve in the Northern Humboldt Current System. Acoustic, biological, and oceanographic information was collected on the pelagic habitat in surveys carried out by the Peruvian Marine Research Institute during the summer and spring of 2018, 2019, and 2020. The results obtained indicated that the spatial occupation of the pelagic habitat of Peruvian anchovy and pelagic red squat lobster were influenced by the dynamics of upwelling, water masses, and a shallow and intense Oxygen Minimum Zone. Spatial overlap of high biomass of Peruvian anchovy and pelagic red squat lobster were recorded in the surface layer during the night. Although, with the presence of dense swarms of múnida in anoxic intermediate waters of the Oxygen Minimum Zone during the day. The Marine Protected Area off...
Marine and Fishery Sciences (MAFIS)
En el presente estudio se caracterizaron agregaciones de krill (Euphasia superba) identificadas e... more En el presente estudio se caracterizaron agregaciones de krill (Euphasia superba) identificadas en el Estrecho de Bransfield y los alrededores de la Isla Elefante. Los datos fueron recolectados con una ecosonda multifrecuencia SIMRAD EK80 durante tres veranos australes 2018, 2019 y 2020. Para la detección de agrega-ciones de krill se utilizaron dos frecuencias (38 y 120 kHz) y un algoritmo incluido en un programa destinado para el post procesamiento denominado Echoview versión 9, automatizado con el paquete EchoviewR en R. Se detectaron un total de 22.221 agregaciones. Los descriptores acústicos fueron analizados con la correlación de Pearson. Para la caracterización de agregaciones de krill se aplicó un análisis de componentes principales (PCA), seguidamente de un agrupamiento jerárquico. Para determinar las diferencias temporales de los clústeres fue aplicado un análisis de varianza ANOVA. Además, a las agregaciones de krill se le asignaron las variables ambientales superficiales ...
Se empleó el método de evaluación hidroacústica durante el crucero BIC Humboldt, Olaya y SNP2 020... more Se empleó el método de evaluación hidroacústica durante el crucero BIC Humboldt, Olaya y SNP2 0209-11, desde Tacna a Piura. El muestreo se realizó de acuerdo a la metodología establecida por el IMARPE. La anchoveta (7.433.429 t) fue la especie más abundante, mostró una distribución costera, continua desde Paita a San Juan, y discontinua hacia el sur de esta localidad; tuvo la mayor abundancia frente al área desde Paita a Punta La Negra y desde Cerro Azul a Tambo de Mora. La múnida (2.418.569 t) fue la segunda especie de mayor abundancia en las aguas costeras frías (ACF), se detectó continua desde Chicama a Pucusana y discontinua de Pisco a Morro Sama. Fueron escasos el jurel (446.782 t) y la caballa (66.246 t); la disminución de estas dos especies se ha registrado desde septiembre 1998. La samasa (28.606 t) se halló costera y escasa; la vinciguerria (5.790.910 t), ampliamente distribuida en el área evaluada, fue más frecuente entre Punta Infiernillos e Ilo, y más abundante desde Chala a Ilo. El bagre (146.362 t), generalmente costero y disperso, frecuente entre Mórrope y Casma y en áreas aisladas de Huarmey a Tambo de Mora, mezclado con la múnida y anchoveta. La pota (878.920 t) se registró en diversas áreas alejadas de la costa, principalmente en aguas subtropicales superficiales (ASS) y en el sur, mezclas ACF + ASS, y hacia el norte, aguas ecuatoriales superficiales (AES) y ACF, tuvo mayor concentración en la zona centro (Punta Bermejo a Pisco). Palabras clave: recursos pelágicos, distribución, biomasa, primavera 2002, mar peruano.
Ecology, 2016
In fluctuating environments, matching breeding timing to periods of high resource availability is... more In fluctuating environments, matching breeding timing to periods of high resource availability is crucial for the fitness of many vertebrate species, and may have major consequences on population health. Yet, our understanding of the proximate environmental cues driving seasonal breeding is limited. This is particularly the case in marine ecosystems, where key environmental factors and prey abundance and availability are seldom quantified. The Northern Humboldt Current System (NHCS) is a highly productive, low-latitude ecosystem of moderate seasonality. In this ecosystem, three tropical seabird species (the Guanay Cormorant Phalacrocorax bougainvillii, the Peruvian Booby Sula variegata, and the Peruvian Pelican Pelecanus thagus) live in sympatry and prey almost exclusively on anchovy, Engraulis ringens. From January 2003 to December 2012, we monitored 31 breeding sites along the Peruvian coast to investigate the breeding cycle of these species. We tested for relationships between br...
During the BIC Humboldt, Olaya y SNP2 0209-11 cruise, the hydroacoustic evaluation method was use... more During the BIC Humboldt, Olaya y SNP2 0209-11 cruise, the hydroacoustic evaluation method was used. The sampling was done according to the methodology established by the IMARPE. The Peruvian anchoveta (7,433.429 t) was the most abundant species; it showed a coastal distribution, continuous from Paita to San Juan, and dashed towards the south of this locality, reached the greater abundance off Paita to Punta La Negra and off Cerro Azul to Tambo de Mora. The vinciguerria (5,790.910 t), widely distributed in the area evaluated was more frequent off Punta Infiernillos and Ilo, and more abundant from Chala to Ilo. The carrot lobster (2,418.569 t) was the second most abundant species in cold coastal waters (CCW), it was found continuous off Pucusana to Chicama and discontinuous off Pisco to Morro Sama. Jack mackerel (446,782 t) and Pacific mackerel (66,246 t); were scarce; the reduction of these two species has been recorded since September 1998. The longnose anchovy (28,606 t) was found ...
The Hydroacoustic Pelagic Resources Assessment survey (Cruise 1909-11) was conducted along the Pe... more The Hydroacoustic Pelagic Resources Assessment survey (Cruise 1909-11) was conducted along the Peruvian coast (03°23'S-18°21'S) between 29 September and 15 November 2019 with the participation of three scientific research vessels from the Peruvian Marine Research Institute (Instituto del Mar del Peru, IMARPE), the R/V Jose Olaya Balandra, the R/V Flores Portugal and the R/V Humboldt. Using the acoustic data collected by the three scientific vessels we estimated the anchoveta biomass using seven hydroacoustic methodologies by applying the following three types of techniques in the processing and subsequent analysis of the eco-acoustic records for the frequencies of 120 and 38 kHz: stratification by isoparalitoral areas; stratification by transects; and by geostatistics. The three best anchoveta biomass estimates were 8.37 million tons obtained with the method of stratification by isoparalitoral areas using the 120 kHz acoustic frequency data; 8.47 million tons obtained with t...
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Papers by Ramiro Castillo