Instituto de Ciencias Naturales Alexander von Humboldt

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A New Species of Encotyllabe Diesing, 1850 (Monopisthocotylea: Capsalidae), from the Pharyngeal Plates of Sciaena deliciosa (Tschudi, 1846) (Eupercaria: Sciaenidae) in Peru, with Notes on the Nomenclatural Status of E. callaoensis Tantaleán, 1974
(MDPI, 2025) Huerta, Andrés; Villena, Carlos; Ramos, Moises; Rojas, Joana; Milla, Kely; Mondragón-Martiínez, Aarón; Ñacari, Luis; Cruces, Celso Luis; Chero, Jhon Darly
A new species of Encotyllabe Diesing, 1850 (Monopisthocotylea: Capsalidae), Encotyllabe tantaliani n. sp., is described from the pharyngeal plates of the Lorna drum, Sciaena deliciosa (Tschudi, 1846) (Eupercaria: Sciaenidae), collected from two localities along the Peruvian coast. This new species was originally proposed as E. callaoensis Tantaleán, 1974, in an unpublished doctoral thesis, and is herein recognized as a nomen nudum under the International Code of Zoological Nomenclature (ICZN). Encotyllabe tantaliani n. sp. is distinguished from all known congeners by the following combination of morphological features: (1) an anteriorly tapering body proper, (2) slightly lobed testes markedly larger than the ovary, (3) vitelline follicles beginning at the level of the male copulatory organ (MCO) and absent from the regions of the reproductive organs, (4) a genital pore positioned posterolateral to the pharynx, and (5) an oblong-shaped MCO. Phylogenetic analysis based on cox1 sequence places E. tantaliani n. sp. in a clade with Encotyllabe percussa Morales-Ávila, Jufaili & Ogawa, 2024, a parasite of Lethrinus nebulosus (Forsskål, 1775) (Eupercaria: Lethrinidae) from the Arabian Gulf. Pairwise genetic distances support the distinctiveness of the new species from its closest congeners. Encotyllabe tantaliani n. sp. represents the first species of the genus described from a host belonging to the Sciaenidae host.
Morphological and molecular characterization of Chauhanellus peruvianus sp. nov. (Dactylogyridea, Dactylogyridae) from Galeichthys peruvianus (Siluriformes, Ariidae) in the Southern Pacific Ocean
(Magnolia Press, 2025) Cruces, Celso L; Ñacari, Luis A; Mondragón-Martiínez, Aarón; Simões, Raquel; Luque, José L; Chero, Jhon D
A new species of Chauhanellus Bychowsky & Nagibina, 1969 is described from the gills of the Peruvian sea catfish, Galeichthys peruvianus L & uuml;tken (Siluriformes, Ariidae), collected from the Southern Pacific Ocean off the coast of Peru. The description of the new species is based on an integrative taxonomic approach, incorporating morphological data, 28S rDNA sequencing, and phylogenetic analysis. Chauhanellus peruvianus sp. nov. can be distinguished from all its congeners by possessing a tubular MCO with proximal and distal curvatures and a spear-shaped distal extremity, as well as an elongated, grooved accessory piece that is proximally expanded and distally hook-shaped. Phylogenetic analyses based on 28S rDNA sequences recovered C. peruvianus sp. nov. in a clade with C. boegeri Domingues & Fehlauer, 2006 and an unidentified Chauhanellus species from Genidens genidens (Cuvier), forming a well-supported Neotropical lineage. However, the genus Chauhanellus was recovered as non-monophyletic, with a separate Indo-Malayan lineage comprising seven species. The description of C. peruvianus sp. nov. represents the first record of Chauhanellus in the Southeastern Pacific and raises the number of species reported from South America and globally to eight and 32, respectively.
Energetic convergence drives metabolic adaptation in lirima chilean high-altitude hydrothermal system
(Springer Nature, 2025) Paquis, Pablo; Pardo Esté, Coral; Tapia, Joseline; Florez, July Z; Pérez, Vilma; Molina, Verónica; Cornejo-D'Ottone, Marcela; Pérez, Pablo A; Harrod, Chris; Jeffrey, Wade H; Calabrese, Sergio; Quatrini, Paola; Tassi, Franco; Hengst, Martha B
High-altitude hydrothermal systems provide laboratories for understanding microbial adaptation to extreme conditions. Here we investigated thermodynamic controls on metabolic transitions in Lirima hydrothermal system (Chile, 4000 meters above sea level) calculating affinities of competing carbon and sulfur reactions across pools (53-75 degrees C). Through geochemistry, numerical thermodynamic modeling, and stable isotope analysis, we identify Energetic Convergence Nodes where chemical affinities of competing pathways become equal. Calculations reveal hydrogenotrophic and carboxydotrophic methanogenesis converge with sulfate reduction at 63-64 degrees C. This corresponds with responses: carbon isotopes shift from -17.2 parts per thousand to -27.7 parts per thousand, sulfur isotopes from -20.5 parts per thousand to -9.1 parts per thousand, and carbon-to-sulfur ratios drop from similar to 10 to <1, indicating transition from carbon to sulfur-dominated metabolism. Microbial activity collapses at this temperature, while metagenomics validates both pathways. Independent analysis confirms convergence at 63-64 degrees C, establishing Energetic Convergence Nodes as predictive frameworks for metabolic boundaries with applications for early Earth biogeochemistry and extraterrestrial biosignature detection.
Unveiling Macroecological Patterns of Elasmobranchs in the Eastern Pacific Ocean
(Wiley, 2025) Navia, Andrés F; Alfaro-Shigueto, Joanna; Ágreda-Arango, Jose; Areano, Elisa; Avalos-Castillo, Cristopher; Bizzarro, Jospeh J; Bustamante, Carlos; Cevallos, Adriana; Concha, Francisco J; Cruz-Escalona, Victor H; Ebert, David A; Espinoza, Maria; González Leiva, Alberto; Guzmán, Héctor M; Hearn, Alex; Hleap, José S; Mangel, Jefrrey C; Mejía-Falla, Paola A; Morales-Saldaña, Jorge M; Santana, Heriberto; Sosa-Nishizaki, Oscar; Tovar-Ávila, Javier; Vélez-Zuazo, Ximena
AimTo examine the species richness, distribution and macroecological patterns of elasmobranch assemblages across a broad latitudinal gradient in the Eastern Pacific Ocean (EPO).LocationThe study area encompasses the Pacific coast of the American continent, spanning from 65 degrees N to 60 degrees S, and extending from the coastline to approximately 1000 km offshore, encompassing the oceanic archipelagos.TaxonElasmobranchs.MethodsUtilising the established distribution ranges of 190 elasmobranch species (comprising 89 sharks and 101 rays), we assessed the richness and spatial distribution of these species across the EPO. Subsequently, three macroecological patterns were scrutinised: Rapoport's rule, the Mid Domain Effect with its association to Mean Sea Surface Temperature, and the correlation between body size and latitudinal distribution.ResultsThe analysis of species richness along latitudinal gradients unveiled a bimodal pattern, reaching peaks between 30 degrees to 20 degrees N and 10 degrees N to 5 degrees S. A decline in species richness was observed from tropical to polar regions. Contrary to Rapoport's Rule, Stevens' and midpoint methods demonstrated higher geographic range values at lower latitudes, diminishing towards higher latitudes. Additionally, the mid-domain effect model exhibited a robust correlation with the mean sea surface temperature. Exploring the interspecific relationship between body size and extent of occurrence, it was found that 29 out of 190 species are more susceptible to extinction.Main ConclusionMarine elasmobranchs of the EPO defy conventional latitudinal richness patterns and deviate from Rapoport's rule. Furthermore, our findings indicate a robust correlation between observed richness and both sea surface temperature and environmental heterogeneity. The proportion of species vulnerable to human or stochastic impacts potentially leading to extirpation in relation to their geographic range was low across the majority of examined provinces.
Shortfalls in the protection of Important Shark and Ray Areas undermine shark conservation efforts in the Central and South American Pacific
(Elsevier, 2025) Mouton, Théophil L; González-Pestana, Adriana; Rohner, Christoph A; Charles, Ryan; García-Rodríguez, Emiliano; Kyne, Peter M; Batlle-Morera, Amanda; Di Sciara, Giuseppe Notarbartolo; Armstrong, Asia O; Acuña, Enzo; Alfaro-Shigueto, Joanna; Arauz, Randall; Avalos-Castillo, Cristopher G; Augustinus, Ely; Bessudo, Sandra; Barraza, Enrique; Bustamante, Carlos; Chávez, Elpis J; Espinoza, Eduardo Ramon; Espinoza, Mario; Hacohen-Domené, Ana; Hearn, Alex R; Hernández, Grettel M; Galván-Magaña, Felipe; González Leiva, José A; Ketchum, James T; Ladino, Felipe; Lara-Lizardi, Frida; Morales-Saldaña, Jorge Manuel; Morales Serrano, Naití; Madrigal-Mesén, Jeffry; Mejía-Falla, Paola A; Navia, Andrés F; Ochoa, Gabriela M; Palacios, Marta D; Peñaherrera-Palma, César R; Polanco-Vásquez, Francisco; Rodríguez-Arriatti, Yehudi; Saldaña-Ruiz, Luz E; Sosa-Nishizaki, Oscar; Tovar-Ávila, Javier; Vega, Ángel J; Vélez-Zuazo, Ximena; Villate-Moreno, Melany; Zanella, Ilena; Jabado, Rima W
Global biodiversity targets require nations to designate 30 % of their marine waters as protected areas by 2030. Sharks, rays, and chimaeras (hereafter ‘sharks’) are key components of aquatic ecosystems; however, over a third are globally threatened with extinction. Across the Central and South American Pacific Ocean region, we (i) assessed trends in Marine Protected Area (MPA) expansion and extent across the 12 nations of the region; (ii) quantified the spatial overlap between MPAs and Important Shark and Ray Areas (ISRAs); and (iii) evaluated the effectiveness of the current MPA governance structure at protecting sharks and their critical habitat. There has been a recent rapid increase in the establishment of MPAs with 90 % of current MPAs designated since 2010. Yet, El Salvador, Guatemala, Peru, and Honduras still protect less than 10 % of their waters. We find that ISRAs overlap with all MPAs by only 15.6 % and with no-take MPAs by 7.3 %. This raises concerns about the low level of protection afforded to critical shark habitats in the region. Of 182 MPAs identified, 41.8 % do not have a management plan, comprising 39.8 % of the total MPA surface area. Mexico, Costa Rica, and Colombia have relatively strong governance frameworks in place and, along with Panama, Honduras, and Ecuador, represent the highest overlap between MPAs and ISRAs. However, the contribution of the remaining six countries to shark protection via MPAs is low based on limited spatial overlap with ISRAs (<2 %). As countries mobilise to meet the 30×30 target, we propose considering ISRAs as a key component of spatial planning when designing new MPAs, designating existing partially protected areas as no-take zones, or reshaping the boundaries of existing MPAs.
New evidence confirms the presence of the diamond stingray Hypanus dipterurus (Jordan & Gilbert 1880) in Chile and extends its southern range
(Wiley, 2025) Almendras, Diego; Villafaña, Jaime A; Bustamante, Carlos; Contreras, Ignacio; Campoy, Ana N; Dufflocq, Pablo; Rivadeneira, Marcelo M
The diamond stingray (Hypanus dipterurus) is a species of cartilaginous fish that,according to the IUCN, is globally in a vulnerable state of conservation and its popula-tions show a decline. New records of this ray species in southern Peru and northernChile have expanded their known range. The species is distributed in the EasternCentral Pacific, from southern California to San Andres, on the central coast of Peru,but is poorly known in Chile. Angler records mined from social media and historicaldata confirmed the presence of H. dipterurus along southern Peru and northern Chile,extending southward over 1250 km. A species distribution model (SDM) based onprevious global occurrences combined with oceanographic layers was built to identifyareas of potential and undocumented presence of H. dipterurus. The SDM showedhigh accuracy (area under the curve = 0.95) and predicted the potential presence ofH. dipterurus along vast areas of the Peruvian and Chilean coasts, where the presenceof the species was poorly documented. Comprehensive surveys are required tounderstand the distribution, population dynamics, habitat requirements, and threatsto effective conservation efforts in the southern region of its distribution range.
Physiological capacity of Pinctada mazatlanica to receive xenografts from Pteria sterna, as a criterion to improve pearl production and quality
(Elsevier, 2025) Trejo-Rodriguez, Karla; Granados-Amores, Andres; Arellano-Martinez, Marcial; Acosta-Salmon, Hector; Campa-Cordova, Angel I; Rojas-Figueroa, Alejandro; Saucedo, Pedro E
This study reports the survival, hemocyte count and physiological response indicators of pearl oysters Pteria sterna and Pinctada mazatlanica seeded with allografts and xenografts for pearl culture. Two treatments of oysters receiving an allograft (both donor and host were Pt. sterna) or a xenograft (donor was Pt. sterna and host was P. mazatlanica) were compared against two control groups of unseeded oysters (allografts and xenografts) at 0, 0.5, 2, 24, and 72 h. While survival was not affected by any particular treatment, the number of circulating hemocytes was inversely proportional in both species; it did not vary in Pt. sterna after allografting from t0 to 2 h, but then gradually increased and reached a 4-fold peak at 72 h that differed significantly from its control group and t0. In P. mazatlanica, the hemocyte count increased significantly (3-fold) at 0.5 h after xenografting, but then gradually decreased to equal the value of its control group and t0 at 72 h. In Pt. sterna, glycogen and mucopolysaccharide indices decreased >50 % at 2 h and gradually returned to the initial value at 72 h. In contrast, neither index varied significantly in P. mazatlanica, indicating almost no use of energy stores to compensate for the effects of xenografting, as well as little mucus production due to tissue irritation, compared to allografting in Pt. sterna. The lipofuscin index followed a relatively stable pattern over time in treatments A and X and changes with respect to their control groups CA and CX were not significant up to 72 h. Our results indicate that P. mazatlanica responded significantly faster to xenografting and wound healing than Pt. sterna to allografting, and may be a viable host to receive Pt. sterna xenografts. This could contribute to improve pearl yield and quality in Pt. sterna.
Morphological and molecular characterization of Neodiplostomum vaucheri Dubois, 1983 (Digenea: Diplostomidae) from Trachops cirrhosus (Spix, 1823) (Chiroptera: Phyllostomidae) in the southern Peruvian Amazon using third-generation sequencing (Oxford Nanopore)
(Cambridge University Press, 2025) Cacique, E. R; Barriga, N; Bello, R; Pino, J; Salcedo-Mejia, L; Nacari, L; Cruces, C; Mondragon-Martinez, A; Chero, J. D
Neodiplostomum vaucheri Dubois, 1983 is a digenean trematode originally described from the intestine of the woolly false vampire bat, Chrotopterus auritus (Peters, 1856), in the northwestern Peruvian Amazon. Decades later, it was also reported from the fringe-lipped bat, Trachops cirrhosis (Spix, 1823), in Ecuador. During a helminthological survey of phyllostomid bats at the Kawsay Biological Station in Madre de Dios, southeastern Peruvian Amazonia, specimens of Neodiplostomum Railliet, 1919 were recovered from the intestine of T. cirrhosus. Morphological comparisons with the holotype confirmed these specimens as conspecific with N. vaucheri. Phylogenetic inference supported the morphological identification, recovering the Peruvian isolate with an N. vaucheri isolate from another South American region within the same clade, with strong support (ML = 90; BI = 0.9587). The observed genetic divergence (4.47% under the Kimura two-parameter model and 4.27% based on uncorrected p-distances) in the partial cox1 sequence may indicate cryptic diversity, as previously noted in congeners. This represents the first integrative characterization of a digenean from a bat host in Peru, contributing to our understanding of parasite diversity in neotropical chiropterans. Furthermore, the use of third-generation sequencing technology (Oxford Nanopore) proved effective for generating reliable partial gene sequences, underscoring its applicability in molecular helminthology.
Modelling 22-years of changes in productivity of the red sea urchin Loxechinus albus in southern Chile using the pre-image population analysis: insights for fishery and conservation management
(Elsevier, 2025) Ortiz, Marco; Diaz, Josue
Pre-image population analysis (PPA) corresponds to a graphic method which allows modelling population dynamics, being able to estimate local population growth parameters using time series of biomass and/or abundance. In this work, PPA was performed using two different types of biomass time series of the exploited red sea urchin Loxechinus albus (Molina, 1782) that inhabit three geographical areas in southern Chile estimating changes in productivity over a period of 22 years. Although the magnitudes of biomass in the time series seem to fluctuate in the analyzed time period, the PPA model parameters in terms of x* (equilibrium values) and r (growth rate, used as a proxy for productivity) showed a reduction between ~15 - 37 % and ~60 - 71 % respectively, highlighting that the Aisen Region (XI) showed the lowest values in both model parameters. Despite the above, the productivity (r) exhibited chaotic dynamics, reaching a flat level in last years. Based on current outcomes, it is suggested to consider the inter-annual magnitudes of equilibrium values (x*) and productivity (r) when determining the exploitation levels for L. albus. Likewise, the direction of change in transient values of productivity (r) could facilitate the monitoring of local populations of L. albus, providing useful information for the adoption of management decisions, such as the setting of fishing quotas and bans. Therefore, PPA could be a useful and complementary technique in estimating dynamic reference points that improve fisheries-management and conservation programs. Finally, it is recommended that PPA could be used as an easy single-species technique to assess the population dynamics of exploited and protected species.
Exploring sustainable scenarios for the brown algae fishery in the intertidal zone along the central Chilean coast (Maule region)
(Elsevier, 2025) Berrios, Fernando; Ortiz, Marco
This work presents the outcomes from five semi-quantitative loop models of different levels of complexity, built to explore and quantify the stability and resilience (used as proxies for sustainability) of the ecological and eco-social systems where intensive artisanal fishing activity of the algae Durvillaea incurvata (Di) and Lessonia spicata (Ls) is occurring in central Chile (Maule Region). The average values for Routh-Hurwitz local stability criterion 1 (Fs) and for Levins’ criterion (Fn) showed that the model systems achieved the desired stability and resilience only when both algae exhibit asymmetric level of abundance (avoiding symmetric competition). Furthermore, both species should exhibit self-negative feedback, that is, their abundances should fluctuate between k/2 and maximum abundance (according to logistic growth). The latter results imply that both algae were the most sensitive to perturbations, regardless of their level of complexity, which limits exploitation strategies and emphasizes the need for integrated management. The substrate (S) also emerged as sensitive in the system. When fishers (F) and demand (D) are dominated by self-negative feedback, the average values of local stability (Fs) and resilience (Fn) were higher than when F and D exhibited self-positive feedback. Therefore, to ensure a sustainable exploitation of both algae, it would be necessary to: maintain the asymmetry of abundance (regardless of which of the two dominates), monitor the quality of the coastal rocky substrate to ensure the colonization of new plants, particularly L. spicata and D. incurvata, and design and implement policies that promote control over the activity of fishers and demand.
High rate of ship strike to large whales off Chile: Historical data and proposed actions to reduce risk
(Elsevier, 2025) Toro, Frederick; Buchan, Susannah J; Alvarado-Rybak, Mario; Bedrinana-Romano, Luis; García Cegarra, Ana M; Hucke-Gaete, Rodrigo; Olavarria, Carlos; Sepulveda, Maritza; Galletti-Vernazzani, Barbara; Sielfeld, Walter; Aguayo, Anelio; Capella, Juan; Perez-Alvarez, Maria Jose; Viddi, Francisco; Caceres, Benjamin; Gibbons, Jorge; Acevedo, Jorge; Guzman, Hector; Guerra, Jorge; Saez, Ricardo; Seguel, Mauricio; Fishbach, M. Michael
Ship strikes are a worldwide threat to large whales as a major cause of mortality and injury. In the Southeast Pacific, this has been poorly studied. In the last decade, an increase in ship strikes has been observed off Chile. This study assesses ship strike mortality in large whales off Chile using data on fatal strandings from the past 52 years, (1972-2023) and vessel traffic patterns. In 63 out of 226 strandings (28 %), ship strike was the direct or probable cause of mortality, i.e. the primary cause of non-natural death in whales. Fin whales (B. physalus) suffered highest total ship strikes (n = 23; 37%), followed by humpback (M. novaeangliae) (n =13; 21 %), blue whales (B. musculus) (n = 7; 11 %), sei (B. borealis) and sperm whales (P. macrocephalus) (n = 6; 10 %). Ship strikes were highest in the Regions of Valparaiso, Coquimbo, Atacama and Antofagasta (Central-Northern Chile), Los Lagos, Aysen and Magallanes (Southern Chile). Since 2013, when necropsies began to be systematically performed, an average of 5 individuals/year have been killed by ships, mostly between January and May. We review all ship strike studies globally and compare rates in Chile with those elsewhere. Based on data between 2013 and 2023, Chile is the country with the highest ship strike mortality globally; considering the entire time series since 1972, Chile ranks number six worldwide. We identify major knowledge gaps and recommend policy measures, including establishing High-Risk Areas and the implementation of shipping lanes modifications and vessel speed restrictions.
Assessing the food web structure of the mesozooplankton community in the highly variable coastal upwelling system of the southeast Pacific
(Elsevier, 2025) Cabrera-Nunez, Susana; Fernandez-Urruzola, Igor; Bode, Antonio; Hernandez-Trujillo, Sergio; Hidalgo, Pamela; Escribano, Ruben
Zooplankton are a key component in the food web of highly productive coastal upwelling systems linking primary producers to higher trophic levels. However, the complex taxonomy, wide size spectrum, and diverse trophic behaviors of zooplankton make it challenging to characterize their food web structure. This study proposes a Trophic Behavior Index (TBI) to assess the trophic structure of zooplankton and test the hypothesis that key biological attributes such as body size, diel vertical migration (DVM) behavior and trophic interactions, rather than environmental factors, primarily shape the food web dynamics of mesozooplankton communities. To this end, we analyzed depth-stratified daytime and nighttime samples of mesozooplankton collected from the upper 900 m at three oceanographically contrasting stations in the Southeast Pacific upwelling system. Vertical gradients in temperature, chlorophyll-a and dissolved oxygen were examined in relation to zooplankton abundance and composition, their DVM behavior, biomass size spectra and trophic position. The proposed TBI was constructed from zooplankton body size assessed by automated image analysis, DVM amplitude and trophic position of taxonomic groups derived from nitrogen stable isotope composition. This index was then compared across environmental conditions, allowing the classification of mesozooplankton into four major trophic functional groups: low predators (primary consumers), moderate predators, strong predators and top predators (very strong predators). Variability in oceanographic conditions influenced the zooplankton community composition and size spectrum; however, our findings suggest that zooplankton body size, DVM behavior and trophic position are the primary determinants of trophic structure. This is reflected in the relative abundance of functional groups, with strong and very strong predators prevailing in offshore areas, whereas the coastal zone was dominated by primary consumers and moderate predators. Overall, our findings support the TBI as a robust community descriptor of zooplankton trophic structure across highly variable oceanographic settings.
Environmental Stability Drives and Maintains the Global Patterns of Phylogenetic Endemism in the Marine Realm
(Wiley, 2025) Rivera, Reinaldo; Gonzalez, Carolina E; Hidalgo, Pamela; Urbina, Mauricio A; Escribano, Ruben
Aim: Endemism is a critical aspect of biological diversity, yet the mechanisms driving it remain unclear. The leading hypoth-esis posits that prolonged environmental stability fosters speciation and reduces extinction rates, promoting endemism. Whileterrestrial studies exist, marine environments remain underexplored. This study analysed the global distribution and drivers ofphylogenetic endemism in two marine taxa: Calanidae copepods and Blenniidae fish.Location: Global.Time Period: From the Last Glacial Maximum (LGM, past 24,000 years) to the current period.Taxa: Calanidae copepods and Blenniidae fish.Methods: We assessed taxonomic and phylogenetic diversity, endemism and areas of paleo- and neo-endemism usingCategorical Analysis of Neo- and Paleo-Endemism and Piecewise Structural Equation Modelling to evaluate the influence ofpresent-day and historical environmental variables.Results: Results showed consistent diversity patterns and significant endemism hotspots, with Calanidae in the SouthernHemisphere and Blenniidae in the Northern Hemisphere. Tropical regions, particularly the Indonesian-Australian Archipelago(IAA), exhibited high species richness and endemism for both groups. Paleo- endemism was observed in the Pacific for Calanidaeand the IAA for Blenniidae, suggesting that these areas are either relict diversity centres or diversification hubs.Main Conclusions: The Mediterranean and Caribbean Seas emerged as biodiversity cradles for Calanidae and Blenniidae re-spectively. Phylogenetic endemism is driven by both historical and contemporary factors, with centres of endemism emergingin regions where past environmental fluctuations have been moderate (hypothesis 1) and where cold, productive ocean currentsfoster the development of endemic areas (hypothesis 2). These findings underscore the importance of historical stability in oceantemperatures in shaping phylogenetic endemism, indicating that long-term environmental stability sustains marine endemism
Fishery biology of the Crevalle jack Caranx hippos (L) from the Colombian Caribbean
(Elsevier, 2025) Pacheco, Carlos; Cusba, Jose; Bustamante, Carlos
The crevalle jack Caranx hippos is a significant fishery resource in the Caribbean Sea; however, biological information necessary for its effective management is currently lacking. To address this gap, this study conducted an integrated multiannual analysis of fishery-dependent data on the size structure, maturity, and spatiotemporal dynamics of landings in six Colombian Caribbean regions. This study found that encircling gillnets, drift gillnets, and seine nets yielded a higher catch in terms of mass, whereas handlines, encircling gillnets, and fixed gillnets captured small and immature specimens. These practices, which affect both adult and immature populations, appear to pose a significant threat to stock health, highlighting the need for preventive approaches to fishery management in Colombian waters. Additionally, the results revealed sexual dimorphism, with females being smaller than males, and the size at maturity of females was estimated at 54.2 cm LT (81 % immature and 19 % mature). Furthermore, this study recorded annual fluctuations in the number of landed specimens at all sites, with La Guajira in the northeastern area of the Colombian Caribbean and Atlántico in the southwest area showing the highest values. The findings suggest a decrease in the size at maturity of C. hippos over a span of ten years, with an average reduction of 2.25 cm LT per year, in response to fishing pressure. In addition, spatiotemporal factors that affect fleet operations play a key role in these fluctuations. This study emphasises the need to adopt comprehensive approaches to improve our understanding of the reproductive dynamics of crevalle jack stocks to ensure the sustainability of artisanal fishing.
Is parasitic infection a buffer against metal pollution?
(Cambridge University Press, 2025) Leiva, N. V; Montenegro, D; Castro, C; Silva, M; Vidal, R; Gonzalez, M. T
Metal pollution is a major global issue in aquatic environments, affecting environmental quality and potentially altering host-parasite dynamics. This study evaluates the buffering role of a larval trematode Himasthla sp. under experimental conditions to test the effect of copper (Cu) exposure on the survival of the marine snail Echinolittorina peruviana. Snails were collected from intertidal rocky pools over a two-month period from Coloso (23 degrees 45'S, 70 degrees 28'W), northern Chile, and identified as parasitized or unparasitized. Both groups were then exposed to Cu concentrations (3 and 6 mg/L). Kaplan-Meier curves were used to determine the percentage of survival over time and the respective confidence intervals (CI). A nested ANOVA was conducted to assess whether rediae abundance per snail varied by experiment time, snail status, and Cu concentration. Snail survival was affected by both Cu-concentrations, but the effect was greater at 6 mg/L. At 3 mg/L, 57% (CI: 49.9-66.6%) of unparasitized snails were alive at 192 h, while 56% (CI: 46.6-67.4%) of parasitized snails survived at 216 h. At 6 mg/L, 42% (CI:35-51%) of unparasitized snails survived at 192 h, while 48% of parasitized snails survived at 216 h (CI:39-59%). Regardless of Cu concentration, after 240 h, all unparasitized snails had died, while 15% of parasitized snails remained alive. Dead snails harboured 125 +/- 53 rediae, while survivors had 194 +/- 73 rediae, with no significant differences between treatments. Our results show that parasitized snails survived longer than unparasitized snails, suggesting a trade-off between parasitism and host survival in polluted environments.
Site fidelity and external health of two distinct fin whale populations from the Northeast and Southeast Pacific Ocean
(Elsevier GmbH, 2025) Guevara, Consuelo; Arriagada, Aracelli; Fishbach, Michael; Van Bressem, Marie-Francoise; Van Waerebeek, Koen; García Cegarra, Ana M
Human activities such as marine traffic, fishing, and pollution are the main threats to large cetaceans, especially to resident whale populations inhabiting heavily exploited enclosed seas or gulfs. Skin is indicative of whale health status because it can display wounds and scars from interactions with fishing gear, boat strikes and natural predators as well as infectious diseases. We evaluated the residence time of two fin whale, Balaenoptera physalus (Linnaeus, 1758) populations: one resident in the Gulf of California (GC), Mexico, and another potentially migratory found at Mejillones Peninsula (MP), Chile. We also compared skin conditions by analyzing photographs for the period 2016–2022. The results show that the GC population is closed while the MP population has a low residence time (5–6 months). The GC population has a significantly higher prevalence of the mesoparasite Pennella sp., commensal Xenobalanus globicipitis and scars from collision with vessels than its MP counterpart. The MP population has a significantly higher prevalence of skin conditions of natural origin such as cookie-cutter shark (Isistius sp.) bites, predation by killer whales, Orcinus orca (Linnaeus, 1758), and orange-brown and green–brown diatom patches than the GC population. These results show that a fin whale population residing year-round in an area with high industrial, fishing, and marine traffic presents more skin conditions related to anthropogenic origin than an oceanic migratory population, which mainly presents scars of natural origins (predation). It is recommended to review the conservation status of the GC resident fin whale population and propose management strategies to guarantee their long-term conservation and welfare.
A genome-based phylogeny for Mollusca is concordant with fossils and morphology
(American Association for the Advancement of Science, 2025) Chen, Zeyuan; Baeza, J. Antonio; Chen, Chong; Gonzalez, Maria Teresa; Gonzalez, Vanessa Liz; Greve, Carola; Kocot, Kevin M; Arbizu, Pedro Martinez; Moles, Juan; Schell, Tilman; Schwabe, Enrico; Sun, Jin; Wong, Nur Leena W. S; Yap-Chiongco, Meghan; Sigwart, Julia D
Extreme morphological disparity within Mollusca has long confounded efforts to reconstruct a stable backbone phylogeny for the phylum. Familiar molluscan groups-gastropods, bivalves, and cephalopods-each represent a diverse radiation with myriad morphological, ecological, and behavioral adaptations. The phylum further encompasses many more unfamiliar experiments in animal body-plan evolution. In this work, we reconstructed the phylogeny for living Mollusca on the basis of metazoan BUSCO (Benchmarking Universal Single-Copy Orthologs) genes extracted from 77 (13 new) genomes, including multiple members of all eight classes with two high-quality genome assemblies for monoplacophorans. Our analyses confirm a phylogeny proposed from morphology and show widespread genomic variation. The flexibility of the molluscan genome likely explains both historic challenges with their genomes and their evolutionary success.
Mild Impact of the 2023 El Niño on Oceanographic and Biological Conditions in the Humboldt Current System
(American Geophysical Union, 2025) Aguilera, Victor M; Barranco, Linda; Dewitte, Boris; Gonzalez, Carolina E; Oerder, Vera; Escribano, Ruben
El Niño is an oceanographic‐atmospheric perturbation that originates atthe equator and subsequently moves poleward along the coasts of the American continent, alteringenvironmental and biological conditions of marine ecosystems. Upwelling supplies nutrients and concentratesplankton near the surface in some of these ecosystems, although it also promotes the transport of water andplankton to the open ocean. We recorded the ecosystem alterations associated with the El Niño 2023 in theHumboldt Archipelago, a biodiversity hotspot situated in a Chilean upwelling region of the Humboldt CurrentSystem. To this end, the abundance of plankton organisms (both phytoplankton and zooplankton), particulatecarbon and oceanographic conditions were assessed during eight nearly‐monthly campaigns. Planktonabundance in the archipelago depends also on local currents that disperse or concentrate particles. Thesecurrents originate from the interaction of winds and a canyon crossing the archipelago. Upwelling persistedduring the period despite the arrival of a warm Kelvin wave in June–July that elevated the sea level andtemperature. The phytoplankton abundance was the lowest after the warm wave, whereas particulate carbon andzooplankton were stable, but there was a significant surface increase during spring. The zooplankton abundancewas related to local environmental conditions, such as food and currents.
Origin, trophic transfer and recycling of particulate organic matter in two upwelling bays of Humboldt Current System: Insights from compound-specific isotopic compositions of amino acids
(Public Library of Science (PLOS), 2025) Srain, Benjamin; Flores, Edgart; Valdes, Jorge; Camano, Andres
The Chilean upwelling bays are highly productive ecosystems shaped by their inter-actions with the open ocean. Although significant knowledge exists regarding their hydrodynamic and ecological processes, the spatial dynamics of trophic transfer and heterotrophic resynthesis of organic matter remain insufficiently understood. To address these knowledge gaps, we conducted a compound-specific isotope analysis of amino acids (CSIAA) on suspended and sinking particulate organic matter from Mejillones and Antofagasta bays, two oceanographic environments characterized by contrasting hydrodynamic conditions and topographic orientations. In Mejillones Bay, the CSIAA trophic positions for metazoan (1.7 ± 0.5) and protozoan (2.3 ± 0.3) were significantly higher compared to those in Antofagasta Bay (metazoans: 1.3 ± 0.6; protozoans: 1.5 ± 0.3), highlighting protozoans as primary trophic vectors. MixSIAR analysis indicated that phytoplankton is a key source of particulate organic matter in both bays; however, Mejillones Bay exhibited a greater proportion of microbially degraded organic matter. Enhanced heterotrophic resynthesis in Mejillones Bay (ΣV: 1.9–2.5) was associated with lower oxygen levels, increased concentrations of NO₂⁻ , and heightened stratification of the water column. Additionally, depth-dependent variations in δ15N for phenylalanine and threonine indicated a greater solubilization of particles, which contributed to a reduction in the export of particulate organic matter (averaging 9 ± 2 mg C/m²/d). These findings underscore the critical role of the intricate interactions between the bay’s topographic features and the physical and biological processes that ultimately influence the cycling trajectories of particulate organic mat-ter in upwelling bays
Unveiling a new species of Trapania (Gastropoda: Nudibranchia: Goniodorididae) from the South-eastern Pacific using anatomical and molecular tools
(Cambridge University Press, 2025) Uribe, Roberto A; Mendivil, Alejandro; Pastor, Ruslan; Atoche-Suclupe, Dennis; Aleman, Solange; Flores, Lorenzo; Sepulveda, Fabiola
Morphological and molecular methods were used to describe a new species ofTrapaniaPruvot-Fol, 1931 from shallow water kelp forests on the north-central coast of Peru. Thenew species,Trapania huarmeyana sp. nov., is distinguished from other species along theEastern Pacific by external morphological characters such as its translucent white bodywith brown stripes and small spots on the dorsum, blotches on the base of the extra-branchialprocesses, extra rhinophoral processes and gill branches. Internally,T. huarmeyanasp. nov. isdistinguishable by several morphological characteristics of the radula, jaws and genital organs.Phylogenetic trees recovered using Bayesian Inference and Maximum Likelihood analysis ofDNA sequences support its distinct status and clarify its relationship to other species fromthe Eastern Pacific. This new species constitutes the first record ofTrapaniafrom theHumboldt Current Ecosystem, contributing to our understanding of the distribution of thegenus in the South-eastern Pacific.

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