Contribución INIDEP 2365
Sobrero, L.; Puente Tapia, F.A.; Chiaverano, L.M.; Macchi, G.J.; Schiariti, A. (2025). Predatory impact on ichthyoplankton by Mnemiopsis leidyi (Ctenophora) is size-dependent: an experimental approach. Marine Ecology Progress Series, 758, 195-201. DOI

Abstract
Understanding the size-related predatory effects of Mnemiopsis leidyi on ichthyoplankton is crucial for evaluating its effects on fish populations. This study examines the capability of M. leidyi to consume ichthyoplankton and assesses whether consumption of fish eggs is dependent on ctenophore size. Laboratory experiments indicated that M. leidyi (4.6-10.5 cm total length) ingest fish eggs and larvae of Seriola lalandi. Ingested fish larvae were fully digested, while eggs were often regurgitated undigested; however, most regurgitated eggs were non-viable. Our results also revealed a significant positive relationship between ctenophore size and egg ingestion. These findings suggest that M. leidyi can consume ichthyoplankton. However, the predatory impact that this ctenophore could exert on fish recruitment in areas where these taxa co-occur will most likely depend on ctenophore abundance and body size.

Contribución INIDEP 2367
Ruiz, M.G.; Mattera Coy, M.B.; Carignan, M.C.; Albornoz, M.; Molinari, G.N.; Montoya, N.G. (2025). Seasonal variability of phytoplankton community structure in a coastal station of the Argentine continental shelf based on a chemotaxonomic approach. Marine and Fishery Sciences, 38(1). https://doi.org/10.47193/mafis.3812025010105

Abstract
The composition, abundance and size structure of the phytoplankton community at a coastal time series station (38° 28' S-57° 41' W, EPEA, Argentina) was characterized by applying the chemotaxonomic approach. The seasonal variability of pigment diversity determined by high-performance liquid chromatography (HPLC, n = 171), nutrient concentration (n = 934), and temperature, salinity and degree of stratification of the water column was identified (n = 190 CTD profiles). The CHEMTAX program was used to estimate phytoplankton abundance in terms of contribution to chlorophyll a concentration of the different phytoplankton pigmentary types (PPTs). Two different pigment indices were compared to estimate phytoplankton community size fractions throughout the year, giving contrasting results. Water column was mostly mixed, with minimum temperatures between July and September and maximum between January-March (range: 8-23 °C). Nitrate was the limiting nutrient, with minimal concentrations at the end of summer. It’s range varied between 0.010-13.330 μM, while silicate ranged between 0.016-10.670 μM without major seasonal variations, and phosphate between 0.120-2.180 μM. Fucoxanthin, chlorophyll c2, 19’-hexanoyl-oxy-fucoxanthin, diadinoxanthin, chlorophyll b, chlorophyll c3, peridinin and, alloxanthin, were the most frequent phytoplankton pigments. The PPT DINO-1 (dinoflagellates with peridinin), haptophytes types: HAPTO-6, HAPTO-7 and HAPTO-P showed a seasonal cycle with peaks of abundance in autumn and spring, while the diatoms DIATO-1 was high during the whole year and DIATO-2 mainly during winter. A pigment profile of a group of prymnesiophytes possessing MVChl_c3 was described. It was evident that at this site PPTs having potentially toxic species bloom under different hydrological conditions. DINO-1 is likely to bloom in April (autumn), with temperatures close to 18 °C and weak stratification conditions, while October bloom (spring) occurs with lower temperatures of 10-12 °C. DINO-4 was noted during January and February (summer), when temperature was > 18 °C, salinity < 33.7, and the water column showed maximum stratification. In contrast, the maximum abundances of DIATO-2 occurred between August and September (winter), under completely mixed conditions, high nitrate concentration and low temperature of 10 °C. This work constitutes the first description of the variability of the abundance of the main PPTs in a coastal a time series station in the southwestern Atlantic Ocean shelf throughout the annual cycle, demonstrating the power of chemotaxonomy and CHEMTAX to perform descriptive analysis of a large number of samples.

Contribución INIDEP 2375
Rosenthal A.F.; Seco Pon, J.P.; González Carman, V.; Denuncio, P. (2025). Registros de varamientos de mamíferos marinos en la Provincia de Buenos Aires, 2010-2022: implicancias para la gestión, conservación e investigación. Mastozoología Neotropical, 32(1). https://doi.org/10.31687/saremMN.25.32.01.02.e1075

Abstract
El monitoreo de mamíferos marinos a través del registro de varamientos es un método de bajo costo que permite conocer la diversidad de especies y tener una aproximación del tamaño de sus poblaciones. Si ese monitoreo se mantiene en el tiempo, resulta una valiosa herramienta para determinar y evaluar cambios en un ecosistema dado. En este estudio se presenta un análisis preliminar de los varamientos de mamíferos marinos registrados en playas de la provincia de Buenos Aires, Argentina, entre los años 2010 y 2022, con el objetivo de evaluar su diversidad especíca en la región, abundancia, frecuencia y variaciones inter e intra-anuales. Los resultados demostraron que el ensamble de mamíferos marinos estuvo compuesto por 15 especies, de ellas, Arctocephalus australis, Pontoporia blainvillei y Otaria avescens fueron las más importantes en orden descendente. De las especies halladas, 11 habitan ambientes tanto neríticos como oceánicos, mientras que el resto de las especies son exclusivamente neríticas u oceánicas. La mayor tasa de varamientos fue de 0,13 ejemplares/km en 2015, mientras que la menor fue de 0,04 en 2021 y 2022. Los análisis estadísticos realizados demostraron una fuerte in uencia de las estaciones del año (variación intra-anual) en el número total de animales varados y en las dos especies más numerosas (A. australis y P. blainvillei). Ante el incremento de las actividades antropogénicas en la plataforma argentina adyacente (p. ej., exploración y explotación de hidrocarburos), este estudio constituye una importante línea de base que re eja la diversidad y tasa de varamientos de las especies de mamíferos marinos en las costas del norte de la Argentina.

Contribución INIDEP 2396
Cepeda, G.D.; Becker, É.C.; Derisio, C.; Severo, A.; Acha, E.M. (2025). Spring copepod functional diversity associated with the oceanographic fronts of the Southwestern Atlantic Ocean. Progress in Oceanography, 232, 103421. https://doi.org/10.1016/j.pocean.2025.103421

Abstract
Studies on species’ functional traits are increasingly used to explore the links between zooplankton community structure and ecosystem functioning. This study investigates copepod diversity across the main frontal types along the continental shelf and shelf break of eastern South America (32°S-55°S), using taxonomic and functional diversity approaches. We analyzed 53 copepod species grouped by five key traits, comparing adult copepod diversity, functional traits, diversity indices, and functional space between frontal systems and surrounding control regions. Contrary to expectations, no significant differences in functional or taxonomic diversity were observed between frontal systems and control regions. Instead, a distinct latitudinal pattern in functional group distribution emerged, shaped by reproductive mode, myelination, feeding traits, and body size. This pattern revealed a decline in species richness, taxonomic diversity, functional richness, and functional space toward southern regions. The findings suggest spatial filtering of specific trait combinations: larger and medium-sized broadcasters and herbivore-omnivore current feeders dominate colder southern systems, while warmer northern systems support a broader array of functional groups, including small-sized sac-spawners, omnivores-detritivores, carnivores, ambush feeders, and cruise feeders. The transition from heterogeneous northern waters—populated by species from the Malvinas Current, subtropical, and subantarctic shelf waters—to colder, less heterogeneous subantarctic waters in the south likely accounts for the greater functional diversity in northern latitudes. These results underscore the role of environmental heterogeneity, species interactions, and ecosystem functioning in shaping copepod communities along the eastern South American continental shelf.

Contribución INIDEP 2397
Pavón Novarín, M.; Meretta, P.; Genzano, G.; Schejter, L. (2025). New northernmost record of Clathria (Clathria) unica and updated records of Cliona aff. celata and Spongia (Spongia) magellanica in Mar del Plata, Argentina, SW Atlantic Ocean. Journal of the Marine Biological Association of United Kingdom, 105. https://doi.org/10.1017/S0025315425000219

Abstract
In this study the finding of the sponge Clathria (Clathria) unica in coastal waters of Mar del Plata city (38°14′24″S, 57°27′30″W), Argentina, at the formation called ‘Banco de Afuera’, is reported. This record constitutes the northernmost record of the species, which was known until the present study only from its type locality in San Antonio Oeste, Río Negro province. Additionally, the bathymetric range of the species is updated from intertidal to 20 m. Other two common sponge species, Cliona aff. celata and Spongia (Spongia) magellanica, were also recorded in this environment for the first time.

Contribución INIDEP 2398
Pavón Novarín, M.; Fernández, J.C.C.; Hajdu, E.; Schejter, L. (2025). Revisiting Asbestopluma (Asbestopluma) magnifica in the SW Atlantic: taxonomic amendments, new insights, and evidence for potential conspecificity with Asbestopluma (Asbestopluma) sarsensis. Journal of the Marine Biological Association of United Kingdom, 105, e20. https://doi.org/10.1017/S0025315425000116

Abstract
In the present study we update the distributional, bathymetric ranges and taxonomic characters of the carnivorous sponge Asbestopluma (Asbestopluma) magnifica Lopez, Bravo & Hajdu, 2011 providing new records for Argentinian jurisdictional waters in the SW Atlantic Ocean, including the Marine Protected Area Namuncurá/Burdwood Bank. The shallowest bathymetric range is now changed to the upper bathyal (289 m depth). We also amend the original description after re-examination of type materials, when markedly different micrometric values were observed for their subtylostyles and acanthotylostrongyles. We noticed a remarkable similarity between Asbestopluma (Asbestopluma) sarsensis Goodwin, Berman, Downey & Hendry, 2017 and A. (A.) magnifica and we suspect they may be synonymous, but we refrain from taking a formal decision pending revision of all materials reported for the younger taxon or a genetic analysis.

Contribución INIDEP 2399
Palumbo, E.; Álvarez C.K.; Rodriguez-Heredia, S.; Rosenthal, A.; Vassallo, M.; Bruno, I.M.; Loureiro, J.; Diaz, L.; Faiella, A.; Werneck, M.R.; Diaz, J.L.; González Carman, V. (2025). Parasite diversity in sea turtles of the temperate SW Atlantic: a bridge between systematics and ecology. Marine Biology, 172. https://doi.org/10.1007/s00227-025-04610-x

Abstract
Parasite studies can provide insights into important aspects of host ecology, which can be particularly important for species of conservation concern. This research focused on the parasite diversity of two sea turtle species —the loggerhead Caretta caretta and the leatherback Dermochelys coriacea— in the temperate South West Atlantic, a region and species relatively understudied. Over a 15-year period (2008–2023), 30 sea turtles were sampled from the northern coast of Argentina. Through morphological and molecular tools, we identified five parasite species (the digeneans Pyelosomum renicapite and Pleurogonius longiusculus, the nematodes Kathlania leptura and Sulcascaris sulcata and the leech Ozobranchus margoi) in loggerheads and two digeneans (P. renicapite and Orchidasma amphiorchis) in leatherbacks. All the species constitute the first report of the parasite in Argentina, and O. amphiorchis represents a new host-parasite association for leatherbacks. Comparative biogeographic analysis using the Regional Management Unit (RMU) framework suggested that parasites could reveal connectivity between RMUs, although there are several information gaps. An increasing number of parasite studies can help understand sea turtle feeding ecology, ontogenetic shifts and health status and thus enhance conservation strategies for sea turtles globally.

Contribución INIDEP 2407
Savoca, M.S.; Abreo, N.A.; Arias, A.H.; Baes, L.; Baini, M.; Bergami, E.; Brander, S.; Canals, M.; Choy, C.A.; Corsi, I.; De Witte, B.; Domit, C.; Dudas, S.; Duncan, E.M.; Fernández, C.E.; Fossi, M.C.; Garcés-Ordóñez, O.; Godley, B.J.; González-Paredes, D.; González Carman, V.; Hamilton, B.M.; Hardesty, B.D.; Hong, S.H.; Kahane-Rapport, S.; Kashiwabara, L.M.; Lacerda, M. B.; Luna-Jorquera, G.; Manno, C.; Nelms, S.E.; Panti, C.; Pérez-Venegas, D.J.; Pham, C.K.; Provencher, J.F.; Purca, S.; Rashid, H.; Rodríguez, Y.; Sparks, C.; Sun, C.; Thiel, M.; Tsangaris, C.; Santos, R.G. (2025). Monitoring plastic pollution using bioindicators: a global review and recommendations for marine environments. Environmental Science: Advances, 4(1). https://doi.org/10.1039/D4VA00174E

Abstract
Monitoring the movement of plastic into marine food webs is central to understanding and mitigating the plastic pollution crisis. Bioindicators have been a component of the environmental monitoring toolkit for decades, but how, where, and which bioindicators are used in long-term monitoring programs has not yet been assessed. Moreover, these programs have yet to be synthesized and evaluated globally. Doing so is imperative if we are to learn from these pioneering programs and expand on their efforts. We reviewed global monitoring programs using bioindicators that focus on plastic pollution and found 11 worldwide that met our definition of long-term monitoring. Limited data availability and few programs in the Global South hinder progress on tracking global trends. Most commonly, long-term programs either tracked macroplastics with opportunistic sampling of large vertebrates or monitored microplastics with targeted sampling of invertebrates. These long-term bioindicators could be incorporated as essential ocean variables in the global ocean observing system, and thus provide critical insights into the trajectory and effects of plastic pollution on marine ecosystems. However, to enhance the effectiveness and inclusivity of these monitoring efforts, there is a pressing need for the implementation of harmonized and standardized methods, increased collaboration between regions, and greater support for data sharing and open science practices. By addressing these challenges and expanding the geographic scope of monitoring programs, we can better inform evidence-based policies and interventions aimed at mitigating plastic pollution on a global scale.

Contribución INIDEP 2420
Alves, N.M.; Spinelli, M.L.; Martín, J.; Malits, A.; Capitanio, F.L. (2025). Ecological role of pelagic appendicularians in sub-Antarctic coastal and oceanic waters of the Southwest Atlantic Ocean. Polar Biology, 48, 28. https://doi.org/10.1007/s00300-024-03331-z

Abstract
Appendicularians are recognized as a prominent mesozooplankton group in pelagic environments due to their abundance and their crucial role in food webs, as they bridge the gap between primary producers and higher trophic levels. Samples were collected during three spring oceanographic surveys conducted in 2014, 2015, and 2016, in the coastal area near Staten Island (SI) and the open sea Marine Protected Area Namuncurá-Burdwood Bank (BB). Surface currents and water properties suggest that BB is relatively isolated from the adjacent regions. We conducted a comparative analysis of density, biomass, and maturity stages of two appendicularians species, Oikopleura fusiformis and Fritillaria borealis, in these two areas with contrasting environmental characteristics. O. fusiformis dominated in both areas, while F. borealis was recorded mainly in the coastal. Higher densities of O. fusiformis were associated with higher chlorophyll-a concentrations in SI, as well as with higher density of pico-nanoplankton in the BB area. No correlation was found between the presence of appendicularians and environmental variables, such as temperature and salinity. However, in coastal areas with higher temperatures, smaller size classes were observed. Occasional occurrences of F. borealis on the BB are tentatively related to intrusions of offshore waters into the bank’s plateau. Nano-picoeukaryotes and bacteria were more abundant in the oligotrophic open sea BB, which could explain the high abundance of appendicularians there. Baseline data of these species in protected areas and surrounding areas are crucial to inform stakeholders and guide responses to future regional and global environmental changes.

Contribución INIDEP 2422
Severo, A.; Acha, E. M.; Cepeda, G.D. (2025). Linking copepod functional traits to diel vertical migration at the Patagonian shelf-break. Marine Biology, 172. https://doi.org/10.1007/s00227-025-04624-5

Abstract
Copepod diel vertical migration (DVM) is a significant phenomenon with implications for the biological pump and pelagic food webs; nevertheless, its drivers and ecological significance are not fully understood. This study analyzed the daytime and nighttime vertical density of females, males, and developmental stages of copepods to investigate the role of functional traits, such as spawning strategy, body size, trophic group, and feeding mode, in DVM at the Patagonian shelf-break (44ºS–47ºS and 60ºW–61ºW). Only females and late copepodites exhibited a normal DVM at oceanic stations, showing their weighted mean depth (WMD) near the surface during the nighttime and at greater depths during the daytime. Fourteen dominant species (the most densely and frequently) were identified based on a relative importance index (RII). Females that are sac-spawners, detritivores, carnivores, omnivores, and/or cruise-feeders exhibited normal DVM, such as Clausocalanus brevipes, Oithona atlantica, Ctenocalanus vanus, Clausocalanus laticeps, Scolecithricella minor, Aetideus armatus, Haloptilus oxycephalus, Metridia lucens, and Candacia longimana, presenting their WMD near the surface and at the fluorescence maxima at nighttime, and below the thermocline at daytime. Conversely, females that are broadcasters, large-sized, herbivores, and/or current-feeders did not exhibit consistent DVM patterns, such as Calanus simillimus, Rhincalanus gigas, and Subeucalanus longiceps, presenting their WMD above the thermocline and at the fluorescence maxima during both daytime and nighttime. Copepod depth selection appears to be influenced by a combination of morphological, physiological, behavioral, and life history traits, that, in each case, would optimize predator avoidance, foraging, and reproduction opportunities.

Contribución INIDEP 2425
Schejter, L.; Genzano, G.N.; Gûller, M.; Maenza, R.A.; Zelaya, D.G. (2025). Massive arrivals of egg capsules of the gastropod Pachycymbiola brasiliana and the hydroid Amphisbetia operculata in the beaches of the Southwestern Atlantic Ocean. Regional Studies in Marine Science, 84. https://doi.org/10.1016/j.rsma.2025.104117

Abstract
The phenomenon of subtidal organisms arriving, accumulating, and depositing onto the beach is not unusual, although they have been seldom documented in South America, especially regarding marine invertebrates. In this study twelve major events that happened at the Atlantic South American shorelines between 35° and 38°S during the austral summer of 2022–2023 were investigated. The arrivals were mainly composed by egg capsules of the gastropod Pachycymbiola brasiliana and by colonies of the hydroid Amphisbetia operculata. Prior to these events, persistent winds from the north/northeast quadrant that promoted moderate to strong currents toward the coastline were recorded. The compilation of other historic events reveals that the 2022–2023 are probably the largest and best documented events involving these species. Great mortality of recruits of the gastropod Pachycymbiola brasiliana may have consequences for the species as well as other members of the local assemblages and food webs. Contrarily, to established populations of the hydroid Amphisbetia operculata, these events pose minimal biological or ecological threats. Unpleasant subsequent conditions for tourists at the beaches are caused by the wrack. This contribution also draws attention to the lack of legislation in Argentina regarding how this wrack should be removed from the beaches.

Contribución INIDEP 2428
Bruno, D.O.; Riccialdelli, L.; Becker, Y.; Martin, J.; Victorio, M.F.; Acha, E.M.; Fernández, D.A. (2025). Ichthyoplankton temporal and spatial patterns in sub-Antarctic coastal and oceanic waters of the Southwestern Atlantic. Estuarine, Coastal and Shelf Science, 318, 109260.
https://doi.org/10.1016/j.ecss.2025.109260

Abstract
The southernmost region of the Southwestern Atlantic (SW Atlantic) has a complex environmental structure with different oceanographic conditions that aid the survival of early life stages of sub-Antarctic fish. This study evaluated the spatial and temporal variations in ichthyoplankton composition of SW Atlantic's sub-Antarctic coastal and oceanic waters and the relationship with environmental variables (water temperature and salinity). Six multidisciplinary oceanographic surveys (austral spring of 2014, 2015, 2016, summer of 2015, and autumn of 2016, 2017) were conducted in two coastal and three oceanic zones of the southern SW Atlantic. A total of 425 fish eggs and 871 fish larvae at the yolk sac (N = 37), preflexion (N = 513), flexion (N = 13), and postflexion (N = 308) stages were collected. Eleven fish taxa in the larval stage were identified. The highest abundance of eggs and larvae in the preflexion stage occurred in spring, dominated by the Fuegian sprat (Sprattus fuegensis) in all zones. However, the abundance of fish larvae in the postflexion stage was higher in autumn at the southern slope of the Burdwood Bank, with a dominance of Patagonian cods (Patagonotothen spp.). Water temperature played a significant role in explaining the abundance of larvae in the preflexion stage, whereas water salinity was significant for eggs and larvae in the postflexion stage. Our results allow us to infer the role of this complex oceanographic system in the early life history of fish. Thus, a conceptual framework for the ichthyoplankton distribution patterns in the area is proposed.