Alejo J. Irigoyen

• Dr.
• Researcher at National Scientific and Technical Research Council

Marine Protected Areas (MPAs) require efficient monitoring tools to assess habitats and biodiversity, particularly in remote or understudied regions. This study demonstrates the utility of the towed video-diver technique combined with high-resolution video for rapidly surveying benthic habitats and associated taxa. Applied in Arredondo, a shallow b...

CAPÍTULO 10. El Golfo San Jorge como área prioritaria de investigación, manejo y conservación en el marco de la Iniciativa Pampa Azul. El Golfo San Jorge (GSJ) fue incluido como una de las áreas geográficas prioritarias en el marco de la Iniciativa Pampa Azul por ser una de las regiones más productivas y con mayor diversidad del Mar Argentino. La...

<<<< 50-day free access link: https://www.ichthyologyandherpetology.org/ihbjbd/ami2023083rf136902dr >>>> Reliable length frequency distributions are useful tools for the assessment and management of fish populations. However, in situ estimation of fish length with single-camera video systems may be inaccurate. The use of allometric changes of the...

Clams belonging to the genus Panopea, part of the Hiatellidae family, are distributed in temperate seas and represent valuable fishing resources in most of the regions where they inhabit. These bivalves tend to aggregate on sandy and/or muddy substrates, exhibiting temporal variations in their abundance, or more precisely, in their detectability. T...

Studies of benthic abundance and biodiversity are essential for fisheries management and environmental impact assessments. In the case of commercial species, such as Tehuelche scallop (Aequipecten tehuelchus), accurate information on the stocks and their densities is crucial. The standard survey method used to estimate abundance of Tehuelche scallo...

The broadnose sevengill shark (Notorynchus cepedianus) is classified as Vulnerable by the IUCN, and its population in the Southwest Atlantic is declining. Despite some progress in understanding the ecological requirements of the sevengill shark, there are still several information gaps. Essential aspects of its trophic ecology, such as main prey it...

Ante la crisis global de pérdida de biodiversidad y deterioro de los ecosistemas, las áreas naturales protegidas tienen un rol preponderante como herramienta de manejo. Sin embargo, la mayoría se basa sobre criterios terrestres, mientras que los organismos de agua dulce son los más amenazados en cuanto a su conservación. En este trabajo se analiza...

Coastal rocky fish species support important fishing activities, but basic information is lacking for many before catches decline. Monitoring and management of coastal rocky fish species is urgently needed in Chile, but knowledge of these species is fragmentary at best. Performance of Baited Remote Underwater Video Stations (BRUVS) for assessing ro...

Essential habitats support specific functions for species, such as reproduction, feeding or refuge. For highly mobile aquatic species, identifying essential habitats within the wider distribution range is central to understanding species ecology, and underpinning effective management plans. This study examined the movement and space use patterns of...

/// Link to full article: https://authors.elsevier.com/a/1gWkGW5UJNpJk /// We investigated changes in the structure of coastal fish assemblages in Northern Patagonia, Southwestern Atlantic, by using baited remote underwater video stations (BRUVS) deployed at increasing distances from rocky reefs: 0–5 m, 15–20 m and 50–60 m. We estimated species ri...

El calentamiento global en los océanos, producido por el incremento de la temperatura, afecta la distribución geográfica de los organismos, así como diversos procesos biológicos (e.g. reproducción, alimentación). Los efectos de las variaciones latitudinales de los hábitats de las especies marinas sobre los ecosistemas y las pesquerías han sido ampl...

The broadnose sevengill shark ( Notorynchus cepedianus ) has been categorized as Vulnerable by the IUCN and shows a declining population trend in the Southwest Atlantic. Bycatch and poaching are the major threats in the region. Although some ecological requirements have been described, there are still several information gaps regarding its ecology....

Population-scale information on the spatial ecology of threatened mobile sharks is required to design more effective management measures. Using an exhaustive collection of presence-only records and relevant predictors, we applied temporally explicit environmental niche modelling to study habitat use by a school shark Galeorhinus galeus population i...

The presence of ladyfish Elops smithi in Patagonian waters is a new addition to the ichthyological fauna of the Argentinean Sea. This record represents a southward ex-tension of its known distribution by 8 degrees of latitude, ~1500 km. It is another ex-ample of the more frequent arrival of tropical or subtropical fish species to Patagonian waters

El Golfo San Jorge (GSJ) fue incluido como una de las áreas geográficas prioritarias en el marco de la Iniciativa Pampa Azul por ser una de las regiones más productivas y con mayor diversidad del Mar Argentino. La región es clave en el ciclo de vida de los recursos pesqueros más importantes de Argentina y cuenta con áreas protegidas destinadas a la...

Cosmopolitan marine pelagic species display variable patterns of population connectivity among the world’s major oceans. While this information is crucial for informing management, information is lacking for many ecologically important species, including apex predators. In this study we examine patterns of genetic structure in the broadnose sevengi...

• Marine protected areas (MPAs) are used as fisheries management and conservation tools. Well‐enforced no‐take zones allow the rebuilding of natural populations of exploited species; however, there is still controversy on the role of buffer zones. • The effectiveness of MPAs could be underestimated, as fish population assessments depend largely on...

A􀑏􀑠􀑡􀑟􀑎􀑐􀑡. Baited Remote Underwater Video Stations (BRUVS) complemented with fishing methods were used to describe the fish assemblage and its seasonal pa􀄴ern in two marine inlets from Patagonia. The combined results for BRUVS and fishing sessions identified 13 fish species. Our results agree with the biogeographic schemes proposed for the southern...

Broadnose sevengill sharks (Notorynchus cepedianus) show great interest for bait and display a repertoire of movements while engaging with it. A novel back-thrust mechanism is described in wild sevengill sharks by which individuals back up from a negative stimulus while interacting with baited video stations. This mechanism initiates upon head cont...

Here we describe massive spawning aggregations and seasonal changes in the large‐scale distribution of the Patagonian grouper Acanthistius patachonicus in the Southwest Atlantic based on three sources of information: (a) data from bottom trawl research surveys covering the distributional range of the species within the Argentine continental shelf;...

En octubre de 2019 se realizó un trabajo de muestreo de Peces en el Parque Nacional el Rey. Se registraron un total de 16 especies, de las cuales, 5 fueron registradas con un único ejemplar, lo cual indica que aún es necesario incrementar considerablemente los esfuerzos de muestreo para tener una muestra representativa de los peces que habitan esta...

Conservation and management measures for large mobile sharks are more effective when information on migratory patterns and environmental cues are known. In the absence of long-term monitoring data or tracking programs, available information is based on occasional catch or sighting records from a variety of sources, usually constrained in space and...

The habitat use, seasonality and demography of the broadnose sevengill shark Notorynchus cepedianus were investigated in central Patagonia, where a data gap exists for the species. Catch and effort and video‐derived indices indicated high relative abundance of sharks during warm months. Video stations revealed differences in the spatial use by shar...

Technological advances in the field of underwater video have led to an exponential increase in the use of drifting cameras (DC) and remotely operated vehicles (ROVs) to monitor the diversity, abundance, and size structure of marine life. Main advantages of DCs relative to ROVs are their lower costs and the much simpler logistics required to operate...

Forage species are key nodes in the energy fluxes between benthic and pelagic zones. The squat lobster, Munida gregaria, is a common forage species of the Southern Hemisphere and its abundance is increasing. This species presents two ecotypes: one (subrugosa) that settles on the sea bottom immediately after the metamorphosis and another (gregaria)...

Low-cost non-scientific echosounders are commonly used for safety and other non-scientific purposes. These echosounders routinely record data which are rarely processed for later use, but which could provide interesting information about the seabed. In this work, we report on the use of a low-cost echosounder for bottom classification in five coast...

Gaining insight on how species relate to the environment and other members of the trophic community is critical for their management. This study investigated habitat use, seasonal patterns of abundance and population structure of the broadnose sevengill shark Notorynchus cepedianus in the marine temperate environment of a northern Patagonian bay (A...

Seasonal fluctuation in environmental parameters can influence immune responses of vertebrates and consequently influence their health and disease resistance. Although seasonality of immune function is well documented in a broad range of vertebrate taxa, this information remains virtually unexplored in cartilaginous fish. Here we examine seasonal v...

Knowledge of the spatial and temporal distribution patterns of chondrichthyans is critical for their effective management. In this study we report and analyze a large-scale latitudinal migration (~ 1,425 km) of a female school shark in the Southwestern Atlantic shelf where it is currently classified as Critically Endangered. During the austral summ...

Underwater visual census (UVC) is the most common approach for estimating diversity, abundance and size of reef fishes in shallow and clear waters. Abundance estimation through UVC is particularly problematic in species occurring at low densities and/or highly aggregated because of their high variability at both spatial and temporal scales. The sta...

In this study the first length–weight relationships are provided for Helcogrammoides cunninghami and Ribeiroclinus eigenmanni inhabiting subtidal rocky areas in northern Patagonia, and for Hypleurochilus fissicornis inhabiting intertidal rocky areas in Buenos Aires Province. Specimens were collected between 2009 and 2016, from seven different locat...

This study aimed to estimate trophic discrimination factors (TDFs) and metabolic turnover rates of nitrogen and carbon stable isotopes in blood and muscle of the smallnose fanskate Sympterygia bonapartii by feeding six adult individuals, maintained in captivity, with a constant diet for 365 days. TDFs were estimated as the difference between δ(13)...

Worldwide, the utilization of underwater video technologies has increased exponentially over the last decades for scientific and commercial purposes. The high quality and diversity coupled with the cost reduction of equipment’s facilitated its utilization among scientists. Remote Operated Vehicles (ROVs) and Drift Cameras (DC) are the most used rem...

La presente invención se refiere a un método para estimar 5 el tamaño de objetos en sistema de video submarino de operación remota y preferentemente se refiere a un método para estimar el tamaño de objetos que utiliza una referencia de tamaño conocida, que al ser captada mediante imágenes de video y/o fotografías, permite escalar y tomar medidas de...

A escala global, los condrictios se encuentran severamente afectados por un amplio rango de actividades antrópicas. Actualmente una gran proporción de poblaciones se encuentran diezmadas y algunas especies son consideradas en peligro de extinción. Los tiburones de gran tamaño y de interés pesquero de la costa Argentina, el escalandrún Carcharias ta...

Pinguipes brasilianus is a conspicuous and abundant rocky-reef fish inhabiting the Northern Patagonian gulfs of Argentina, Southwest Atlantic. This study describes its reproductive biology in this region. We made macroscopic and histological descriptions of the testis and ovary development, analyzed the evolution of the gonadosomatic index (GSI) in...

Knowing the movement patterns of a certain species has substantial implications for its management and conservation, particularly in species that migrate hundreds to thousands of kilometers each year (e.g., many chondrichtyans). The objective of this paper was to study the seasonal abundance in the Golfo Nuevo and the migratory patterns of the scho...

Knowing the movement patterns of a certain species has substantial implications for its management and conservation, particularly in species that migrate hundreds to thousands of kilometers each year (e.g., many chondrichtyans). The objective of this paper was to study the seasonal abundance in the Golfo Nuevo and the migratory patterns of the scho...

In line with global targets agreed under the Convention on Biological Diversity, the number of marine protected areas (MPAs) is increasing rapidly, yet socio-economic benefits generated by MPAs remain difficult to predict and under debate1, 2. MPAs often fail to reach their full potential as a consequence of factors such as illegal harvesting, regu...

In this note, we report the occurrence of H. niveatus at two new locations in Argentine waters, extending its range c.1000 km southwards of the previously reported limit.

The choice of appropriate conservation strategies for reef fishes depends on their mobility, degree of site fidelity and residence times. Here we report the results of a small-scale mark–recapture and resighting study conducted to investigate the spatial dynamics of the Argentine sandperch, Pseudopercis semifasciata. This is the flagship species of...

Statistical models. Hierarchical random-effect model used to estimate variance components for each species. (DOC)

Details of sampling design. Dates and sampling hours for time-of-day and tide experiments. (DOC)

Identifying sources of sampling variation and quantifying their magnitude is critical to the interpretation of ecological field data. Yet, most monitoring programs of reef fish populations based on underwater visual censuses (UVC) consider only a few of the factors that may influence fish counts, such as the diver or census methodology. Recent stud...

Several flexible methods for estimating tag loss rates through mark-resight data have been developed recently. They allow evaluation of different tag shedding modalities and relax the usual assumption of independence between the loss of tags made in classical double-tagging methods. Two conditions limit the applicability of these methods: (1) tagge...

Descripcion de los equipos desarrollados y la tareas realizadas por el grupo de trabajo.

VIII Jornadas Nacionales de Ciencias del Mar, XVI Coloquio de Oceanografía

Changes in macroalgal community structure caused by invasive seaweeds have strong impacts on the associated macrofauna due to the role of macroalgae as autogenic ecosystem engineers. This study investigates the effect of Undaria pinnatifida on the abundance and diversity of benthic macrofauna in Golfo Nuevo, northern Patagonia, using a manipulative...

Since the introduction of Undaria into Nuevo Gulf, Argentina, around 1992, this alien seaweed has now colonized different sites over 700km of coast, forming dense seasonal forests in waters from 0 to 15 meters in depth. In the spring it is common for plants of Undaria to break away from the substrate and be transported by sea currents. As Undaria g...

I Jornadas Patagónicas de Biología y III Jornadas Estudiantiles de Ciencias Biológicas.

A checklist containing 29 species of reef fishes recorded at the gulfs San José and Nuevo in Argentina (~42º–43ºS) is provided. The reef-fish assemblages of the San José and Nuevo gulfs are a mix of warm-temperate fauna from the South-western Atlantic Province, and cold-temperate species from the South-American Province; however, warm temperate fis...

We review the species of Acanthistius Gill (1862) (Osteichthyes, Percoidei) from the South-Western Atlantic, solving a discrepancy concerning the taxonomic status of Acanthistius brasilianus (Cuvier & Valenciennes 1828) and Acanthistius patachonicus (Jenyns 1842), and providing an objective diagnostic key for the two species. While Argentinean fish...

We review the species of Acanthistius Gill (1862) (Osteichthyes, Percoidei) from the South-Western Atlantic, solving a discrepancy concerning the taxonomic status of Acanthistius brasilianus (Cuvier & Valenciennes 1828) and Acanthistius patachonicus (Jenyns 1842), and providing an objective diagnostic key for the two species. While Argentinean fish...

We describe a new manual procedure for catching and tagging fish underwater, the ‘pole-hooking’ method, and demonstrate and discuss its advantages over standard tagging techniques (i.e. hook-and-line fishing). The new technique was designed for tagging Acanthistius brasilianus [Cuvier, M., Valenciennes, L.B., 1828. Histoire Naturelle des Poissons....

FIGURE 1. Geographic ranges of Acanthistius brasilianus (dotted line, 15 º to 23 º S) and A. patachonicus (solid line, 23 º to 48 º S). (1) Type locality of A. brasilianus (15 º S, off Ilehus); (2) Type localities of A. patachonicus, off Argentina (near mouth of La Plata River and 38 ° 20 ’ S).

FIGURE 4. Opercular and preopercular spines. (A) Acanthistius brasilianus. (B) A. patachonicus.

FIGURE 3. Photographs of Acanthistius brasilianus, recently caught (top) and in its natural habitat, Arraial do Cabo, Brazil, March 2007 (bottom).

FIGURE 2. Reference specimens. (A) Syntype of Acanthistius brasilianus (MNHN, Paris). (B) “ Topotypic ” specimen of A. patachonicus collected in the immediacy of one of the two type localities (MACN Buenos Aires 5004, 38.4 ºS, 1963, TL 24.6 cm, preserved in ETOH).

FIGURE 5. Photographs of Acanthistius patachonicus, recently caught (top) and in its natural habitat Golfo Nuevo, Argentina 2006 – 2007 (bottom).

The occurrence of the dusky grouper Epinephelus marginatus in northern Patagonian Gulfs San Matías and Nuevo, Argentina, is recorded. This finding represents the southernmost record of the species for the southern hemisphere.