Abstract Nototheniidae is the most numerous family of notothenioids and, although they are mainly Antarctic, they are also well represented in Patagonian waters. In both Antarctic and sub-Antarctic waters, they adopt a wide variety of reproductive strategies. In Antarctic waters they usually have a biennial reproductive cycle, whereas in sub-Antarctic ones, they reproduce annually or biannually. In the intertidal zone of central Patagonia the most abundant nototheniid fish is Patagonotothen cornucola and, despite this, there is little information about their biology. The aim of this work was to study its reproductive cycle in a rocky intertidal coast of Argentine Patagonia by means of histological and morphological analyses. Samples were collected monthly at two intertidal sites in the San Jorge Gulf. Condition factor, gonadosomatic and hepatosomatic indexes were calculated and thin sections of gonads were stained with one-step trichrome to determine gonadal stages. Relative and potential fecundity were also estimated. Males and females mature synchronously and reach maximum gonadosomatic index between July and August. In females the hepatosomatic index increases synchronously with gonadosomatic index, while in males it remains constant throughout the cycle. It is concluded that P. cornucola has an annual reproductive cycle and that spawning occurs in winter. Maximum potential fecundity is approximately 27,095 oocytes in a 11.7 cm female and it increases with size.

Resumen La familia Nototheniidae es la más numerosa entre los nototénidos y, a pesar de ser principalmente Antárticos, están muy bien representados en aguas patagónicas. Desde la Antártida hasta las aguas de Sudamérica, han adoptado una gran variedad de estrategias reproductivas. Los peces antárticos suelen tener un ciclo reproductivo bienal mientras que en aguas sub-antárticas los nototénidos pueden reproducirse anualmente o bianualmente. En la zona intermareal de la Patagonia central, el pez más abundante es Patagonotothen cornucola y, a pesar de esto, hay poca información sobre su biología. Por esto, el objetivo principal de este trabajo fue estudiar su ciclo reproductivo en la zona intermareal rocosa usando métodos histológicos y morfológicos. Las muestras fueron recolectadas mensualmente en dos sitios intermareales en el Golfo San Jorge, y se calculó el factor de condición, índices hepatosomáticos y gonadosomáticos y se realizaron cortes histológicos de las gónadas que fueron teñidas con tricrómico de un tiempo para determinar los estadios gonadales, además se estimó la fecundidad potencial y relativa. Se determinó que machos y hembras maduran sincrónicamente alcanzando los valores máximos de índices gonadosomáticos entre julio y agosto. En las hembras el índice hepatosomático aumenta simultáneamente con el gonadosomático mientras que en machos se mantiene constante durante todo el ciclo. Se concluye que P. cornucola tiene un ciclo reproductivo anual y que el desove ocurre en el invierno. La fecundidad potencial máxima fue de 27.095 oocitos en una hembra de 11,7 cm y se incrementa con la talla.

Abstract Introduction: The species of the Crinoidea and Asteroidea classes are distributed in a wide variety of habitats in all oceans from the intertidal zone to great depths, there are few Mexican records in depths greater than 200 m, the few existing records date from historical documents in the specialized literature and the specimens are kept in foreign scientific collections. Objective: Contribute to the collection of information on the specimens kept in the Colección Nacional de Equinodermos (CNE) of Instituto de Ciencias del Mar y Limnología (ICML), UNAM and provide an inventory of the species of crinoids and asteroids that inhabit deep areas of the slope of the Yucatan Peninsula, Mexico. Methods: From 2005 to 2014, specimens of crinoids and asterioids were collected through four cruises in the B/O “Justo Sierra” BIOREPES 1 and 2 and COBERPES 2 and 6, shrimp net trawls were carried out at 80 sampling stations. Results: The taxonomic list includes 1146 specimens, of which 204 crinoids are of the order Comatulida, distributed in three families, three genera and three species and 942 asteroids distributed in six orders, 11 families, 21 genera and 28 species. New records were obtained for CNE: Democrinus rawsonii and Atelecrinus balanoides in crinoids. Astropecten alligator, Hymenaster modestus, Calyptraster personatus, Pteraster militarioides militarioides, Sclerasterias contorta in asteroids. With this information, the records of crinoids and asteroids (deeper than 200 m) increase for the states of Yucatan (16) and Quintana Roo (16).

Resumen Introducción: Las especies de las clases Crinoidea y Asteroidea se distribuyen en gran variedad de hábitats en todos los océanos desde la zona intermareal hasta grandes profundidades, existen pocos registros en aguas mexicanas, a profundidades superiores a los 200 m, los escasos registros existentes datan de documentos históricos de la literatura especializada y los ejemplares se resguardan en colecciones científicas extranjeras. Objetivo: Contribuir a la recopilación de información de los ejemplares resguardados en la Colección Nacional de Equinodermos (CNE) del Instituto de Ciencias del Mar y Limnología (ICML), UNAM y proveer un inventario de las especies de crinoideos y asteroideos que habitan en zonas profundas del talud de la Península de Yucatán, México. Métodos: Del año 2005 al 2014 se recolectaron ejemplares de crinoideos y asteriodeos en cuatro cruceros en el B/O “Justo Sierra” BIOREPES 1 y 2 y COBERPES 2 y 6. Se realizaron arrastres con red camaronera en 80 estaciones de muestreo. Resultados: El listado taxonómico comprende 1146 ejemplares, de los cuales 204 son crinoideos del orden Comatulida, distribuidos en tres familias tres géneros y tres especies y 942 asteroideos distribuidos en seis órdenes, 11 familias, 21 géneros y 28 especies. Se obtuvieron los registros nuevos para la CNE: Democrinus rawsonii y Atelecrinus balanoides en crinoideos. Astropecten alligator, Hymenaster modestus, Calyptraster personatus, Pteraster militarioides militarioides, Sclerasterias contorta en asteroideos. Con esta información se incrementan los registros de crinoideos y asteroideos (de profundidad mayor a 200 m) para los estados de Yucatán (16) y Quintana Roo (16).

Resumo As espécies simpátricas de caranguejo-da-lama Panopeus americanus e Panopeus austrobesus são encontradas em ambientes entremarés associados a habitats lamacentos e rochosos, bem como em simpatria na costa do Atlântico Ocidental. Portanto, constituem um sistema modelo adequado para ser utilizado em estudos focados na investigação de aspectos de coexistência biológica entre espécies semelhantes, como estrutura populacional e habitat. Os objetivos do presente estudo são descrever e comparar a microdistribuição de duas espécies simpátricas de caranguejo-da-lama – P. americanus e P. austrobesus – com base na avaliação de sua distribuição espacial e temporal, em uma área estuarina complexa e com baixo impacto antrópico. A hipótese de que estas duas espécies apresentam microdistribuição semelhante, embora uma espécie seja mais abundante que a outra, foi testada. A amostragem foi realizada na zona entremarés de uma área específica do complexo estuarino de Cananeia, Estado de São Paulo, Sudeste do Brasil, em diferentes períodos durante dois anos. Ambas as espécies apresentaram microdistribuição e frequência semelhantes, principalmente nas zonas entremarés média e alta. Entretanto, Panopeus americanus foi mais abundante e apresentou menor tamanho médio em todas as zonas amostrais. A pronunciada disparidade de tamanho entre as espécies sugere preferências alimentares divergentes, potencialmente relacionadas ao tamanho das presas possibilitando a coexistência dessas espécies simpátricas. A predominância dessas duas espécies nas zonas intermareais superiores também indica uma estratégia para evitar a competição com os camarões alfeídeos. caranguejodalama caranguejo da lama rochosos Ocidental Portanto semelhantes habitat P temporal antrópico semelhante outra testada Cananeia Paulo Brasil anos alta Entretanto amostrais divergentes alfeídeos

Abstract Sympatric mud crab species Panopeus americanus and Panopeus austrobesus are found in intertidal environments associated with muddy and rocky habitats in the Western Atlantic coast. Therefore, they are a suitable model system to be used in studies focused on investigating biological coexistence aspects between close species, such as population structure and habitat. The aims of the current study are to describe and compare the distribution of two sympatric mud crab species – P. americanus and P. austrobesus – based on their spatial and temporal distribution, in a low human impact estuarine complex area. The hypothesis that these two species show similar distribution, although one species is more abundant than the other, was herein tested. Sampling was carried out in the intertidal zone of a specific area in Cananeia estuarine complex, São Paulo State, Southeastern Brazil, in different periods of time for two years. Both species presented similar pattern distribution and frequency, with predominance in the middle and high intertidal zones, including all demographic categories. However, Panopeus americanus was more abundant and presented smaller mean size in all sampling zones. The pronounced disparity in size between the species suggests divergent dietary preferences, potentially related to prey size allowing the coexistence of these sympatric and syntopic species. The predominance of these two species in the upper intertidal zones was understood as a strategy for avoiding competition with the intertidal alpheid shrimps. coast Therefore habitat P other tested State Brazil years frequency categories However preferences shrimps

Resumen Introducción: La contaminación por microplásticos es un problema global en los ecosistemas marinos, con impacto sobre microorganismos y ecosistemas en varios niveles espaciales. Las playas arenosas son ambientes de deposición donde se tiende a acumular gran cantidad de microplásticos. La co-ocurrencia de meiofauna intersticial y microplásticos en granos de arena plantea la pregunta de que si la acumulación de microplásticos en sedimentos afecta la abundancia y composición de comunidades de meiofauna. Objetivo: Probar la hipótesis de que microplásticos afectan la meiofauna de playas arenosas urbanas. Métodos: Estudiamos las tres principales playas arenosas urbanas de Santa Marta, Colombia: El Rodadero, Bahía Santa Marta y Taganga. Estas son similares en morfología y presiones externas, y difieren de las otras playas de la región. En abril 2019 recolectamos 81 muestras de arena, distribuidas de manera equidistante en la zona intermareal (nivel intermareal superior, medio y bajo). Aplicamos modelos lineales generalizados de abundancia, y pruebas permutacionales multivariantes a la composición de comunidades. Resultados: Identificamos 17 grupos taxonómicos de meiofauna, y partículas de microplástico (principalmente fibras de 45-500 micras) distribuidos equitativamente a lo largo de las playas y niveles intermareales. Hubo más meiofauna en el nivel intermareal medio, y en sedimentos de grano mediano y fino. A niveles intermareales más bajos, sitios con más microplásticos tuvieron menos meiofauna. La abundancia de los microplásticos explicó el 39 % de la variación en comunidades de meiofauna a niveles intermareales bajos. Conclusión: La acumulación de microplásticos podría tener un impacto negativo sobre las comunidades de meiofauna intersticial. Esto no es de sorprender: si los microplásticos ocupan el mismo volumen físico que estos animales, estos podrían presuntamente modificar la estructura de sedimentos y la composición del agua intersticial.

Abstract Introduction: Pollution by microplastics is a global problem in marine environments, which impacts microorganisms and ecosystems at several spatial levels. Sandy beaches are depositional environments where microplastics tend to accumulate in large quantities. The co-occurrence of interstitial meiofauna and microplastics in sand grains raises the question on whether the accumulation of microplastics in the sediments affects the abundance and composition of the meiofaunal communities. Objective: To test the hypothesis that microplastics affect the meiofauna of urban sandy beaches. Methods: We studied the three main urban sandy beaches of Santa Marta, Colombia: El Rodadero, Santa Marta Bay, and Taganga. All are similar in morphology and external pressures, and differ from other beaches in the region. In April 2019 we collected 81 sand samples, equally distributed in the intertidal zone (upper, mid, and lower intertidal levels). We applied generalized linear models to abundance, and multivariate permutational tests to community composition. Results: We identified 17 taxonomic groups of meiofauna, and microplastic particles (mainly 45-500 micron fibres) evenly distributed across beaches and intertidal levels. There was more meiofauna at the mid intertidal level, and in fine and medium grain sediment. At the lower intertidal level, sites with more microplastics had less meiofauna. Abundance of microplastics explained 39 % of the variation in meiofaunal community composition at lower intertidal levels. Conclusions: The accumulation of microplastics might have a negative impact on these meiofaunal interstitial communities. This is not surprising: if microplastics occupy the same physical space as these animals, they might presumably modify the structure of sediments and the composition of interstitial water.

ABSTRACT Background. Coastal environments such as the intertidal zone and rocky and coral reefs are exposed to natural disturbances such as tides, storms, hurricanes, and cyclones and human activities such as fishing, tourism, and pollution. The deep reef refuge hypothesis posits that organisms that can inhabit greater depths would be less vulnerable to anthropogenic impacts, greenhouse warming of the sea surface, and ocean acidification caused by the increased partial pressure of CO2. Consequently, deep rocky or coral reefs can function as “insurance” against the effects of climate change. Objective. To analyse biotic and abiotic variables of the mesophotic ecosystem of Archipelago Espíritu Santo to assess it as a refuge against climate change-related disturbances. Methods. Bathymetry, profiles of temperature, salinity, and dissolved oxygen; determination of the euphotic zone, sampling in shallow and deep waters collecting water for analysis of carbonate system, video transects with remotely operated vehicles for the identification of benthic species and estimation of their abundance including those of commercial importance or conservation. Calculation of ecological indices and the reef-functional index. Results. Deepest recorded point was 78m, shallowest mesophotic zone was 11m. Temperature does not show a stratification either in April or in October 2021, but the salinity registers a peak near 30 m depth, and the dissolved oxygen decreases at 20 m. Ω Aragonite is below 3.0; there is spatial variation in the structural indices of the benthic community, and the reef-functional index is between 0.16 and 0.65. Conclusions. There are sharp spatial variations within the same locality, limiting the assertion that mesophotic ecosystems can serve as a refuge from climate change.

RESUMEN Antecedentes. Los ambientes costeros como la zona entremareal y los arrecifes rocosos y coralinos están expuestos a perturbaciones naturales como las mareas, tormentas, huracanes y ciclones y actividades humanas como la pesca, turismo y contaminación. La hipótesis del refugio profundo postula que los organismos que pueden habitar a mayores profundidades serían menos vulnerables a los impactos antropogénicos, el calentamiento superficial del mar derivado del efecto invernadero y a la acidificación del océano provocada por el incremento en la presión parcial de CO2. En consecuencia, los arrecifes rocosos o coralinos profundos podrían funcionar como un “seguro” contra los efectos del cambio climático. Objetivos. Analizar variables abióticas y bióticas del ecosistema mesofótico del archipiélago Espíritu Santo, BCS para considerarlo como refugio ante perturbaciones relacionadas con el cambio climático. Métodos. Batimetría, determinación de la zona euofótica, perfiles de temperatura, salinidad y oxígeno disuelto, muestreos en aguas someras y profundas, recolección de agua para análisis del sistema de carbonatos, videotransectos con vehículos de operación remota para la identificación de especies bénticas y estimación de su abundancia, incluyendo las de importancia comercial o de conservación. Cálculo de índices ecológicos y del índice de función arrecifal. Resultados. La profundidad máxima registrada fue de 78 m y el inicio de la zona mesofótica (10% de penetración luminosa) más somero fue de 11 m; la temperatura no muestra una estratificación ni en abril ni en octubre de 2021, pero la salinidad registra un pico cerca de los 30 m de profundidad y el oxígeno disuelto disminuye a los 20 m. La Ω aragonita está por debajo de 3.0; hay variación espacial en los índices estructurales de la comunidad béntica y el índice de función arrecifal se encuentra entre 0.16 y 0.65. Conclusiones. Hay variaciones espaciales que limitan afirmar que el ecosistema mesofótico pueda servir de refugio ante el cambio climático en esta localidad.

Abstract Calloplax vivipara (Plate, 1899) is formal recorded for the first time in the southern Peruvian coast. Four specimens were found in rocky intertidal environment under blocks of stones in Islay, Arequipa, in December 2013 and October 2019. A female of 9.2 mm body length collected in the spring of 2013 presented six juveniles in the external part of the insertion zone of the ctenidia in the pallial groove, constituting the first case of an incubating chiton in Peru.

Resumen Calloplax vivipara (Plate, 1899) se registra formalmente por primera vez en el litoral sur peruano. Cuatro ejemplares fueron encontrados en el intermareal pedregoso debajo de bloques de piedras en Islay, Arequipa, en diciembre de 2013 y octubre de 2019. Una hembra de 9.2 mm de longitud del cuerpo colectada en la primavera del 2013 presentó seis juveniles en la parte externa de la zona de inserción de los ctenidios en el surco paleal, constituyendo el primer caso de un quitón incubador en Perú.

Abstract: Background and Aims: Since the publication of the book on Cuban marine macroalgae in 2015, new records have been found and taxonomic changes have been published. Therefore, the objective of this publication is to present a fifth updated systematic review, that includes Ochrophyta (Class Phaeophyceae), Rhodophyta and Chlorophyta. Methods: These results were recorded from information available in scientific papers, bachelor, master and doctoral theses, as well as scientific-technical reports from recognized specialists, considering those not included in the last review or that were published after 2015. The taxa were systematically ordered, the names and synonymy were reviewed according to Algaebase and the most recent scientific literature. Species were arranged alphabetically within each family. The distribution of each taxon was resumed for nine Ecological Districts (zones) of the Cuban shelf. Key results: An updated floristic list with 569 species, one subspecies, 25 varieties, and 21 forms is presented. Thirty-seven species are added to the previous review of which seven are new records for Cuba: Hydrolithon boergesenii, Neogoniolithon mamillare, N. propinquum, N. rhizophorae, Lithothamnion crispatum, Liagoropsis schrammii, and Peyssonnelia rubra. The distribution of these taxa in the nine zones of the Cuban shelf is provided. Conclusions: The zones showing more species have had a greater sampling effort or were predominantly rocky reef bottoms. However, macroalgae have not been inventoried in detail in the intertidal zone, bays, and coastal lagoons. Zones with fewer species coincide in having a narrower shelf where rocky substrates dominate, although macroalgae have not been inventoried in the intertidal zone, bays, and coastal lagoons.

Resumen: Antecedentes y Objetivos: Desde la publicación del libro sobre las macroalgas marinas de Cuba en 2015 se han publicado nuevos registros y cambios taxonómicos. Por lo anterior, el objetivo del presente trabajo fue presentar una quinta revisión sistemática actualizada, que incluye Ochrophyta (Clase Phaeophyceae), Rhodophyta y Chlorophyta. Métodos: Se recopiló la información disponible en publicaciones científicas, tesis de licenciatura, maestría y doctorado, e informes científico-técnicos de especialistas reconocidos, considerando aquellas que no fueron comprendidas en la revisión anterior o que fueron publicadas después de 2015. Los taxones encontrados fueron ordenados sistemáticamente, los nombres actualizados y la sinonimia revisada según AlgaeBase y la literatura más reciente. Las especies se ordenaron alfabéticamente dentro de cada familia. La distribución de cada taxón se resumió para nueve zonas consideradas como Distritos Ecológicos (zonas) de la plataforma cubana. Resultados claves: Se presenta un listado florístico actualizado con 569 especies, una subespecie, 25 variedades y 21 formas. Se añaden a la anterior revisión 38 especies, de las cuales siete son nuevos registros para Cuba: Hydrolithon boergesenii, Neogoniolithon mamillare, N. propinquum, N. rhizophorae, Lithothamnion crispatum, Liagoropsis schrammii y Peyssonnelia rubra. Se da la distribución de cada uno de estos taxones en las nueve zonas de la plataforma cubana. Conclusiones: Las zonas que presentaron más especies son aquellas que han tenido un mayor esfuerzo de muestreo o donde predominan los fondos rocosos arrecifales, aunque no se han inventariado detalladamente las macroalgas en la zona mesolitoral, bahías y lagunas costeras.

Abstract The physiological process to counteract environmental stress are extremely diverse in marine species that inhabit intertidal zones. Ecological approaches have demonstrated a variety of adaptations among narrowly distributed species. The present study is focused on physiological responses of two key marine gastropods from Atlantic Patagonia living in one of the most stressful intertidal rocky shores of the world: Tegula patagonica and Trophon geversianus. We evaluated the body temperature and its heat-shock response by Hsp70 expression. Our results suggest that T. geversianus, inhabiting the mid-intertidal zone and exposed for longer to aerial conditions, presents better physiological and behavioral adaptations to temperature than T. patagonica, living in the low intertidal with less physical stress. Tegula patagonica seems to have an inefficient thermal defense, an inability to upregulate Hsp70 expression against water temperature increase. Contrariwise, a significant upregulation of Hsp70 was registered in T. geversianus added to a protective behavior of hiding during periods of high tempera ture. These results will be useful as a reference for monitoring sentinel species to assess real-time changes in coastal intertidal communities due to global warming.

Resumen Los procesos fisiológicos para con trarrestar el estrés ambiental en las especies marinas que habitan las zonas intermareales son extremadamente diversos. Los enfoques ecológicos han demostrado una variedad de adaptaciones entre especies de distribución limitada. El presente estudio se focaliza en las respuestas fisiológicas de dos gasterópodos marinos clave de la Patagonia atlántica que viven en una de las costas rocosas intermareales más estresantes del mundo: Tegula pata gonica y Trophon geversianus. Evaluamos la temperatura corporal y su respuesta al choque térmico mediante la expresión de Hsp70. Nuestros resultados sugieren que T. geversianus, habitante del intermareal medio y expuesto por más tiempo a las condiciones aéreas, presenta mejores adaptaciones a la temperatura en comparación a T. patagonica, que habita en el intermareal bajo con menor estrés físico. Tegula patagonica parece tener una defensa térmica ineficiente, incapaz de incrementar la expresión de Hsp70 frente al aumento de la temperatura del agua. Por el contrario, se registró un aumento significativo de Hsp70 en T. geversianus sumado al comportamiento defensivo de esconderse durante los períodos de alta temperatura. Estos resultados serán útiles como referencia para monitorear especies centinela y evaluar cambios en tiempo real en las comunidades intermareales costeras debido al calentamiento global.

Resumen: En el Ecuador, el estudio de equinodermos se ha enfocado en Áreas Protegidas (AP), propiciando nuevas investigaciones en otras zonas rocosas externas a una AP. El objetivo de esta investigación fue describir la composición y estructura comunitaria de los equinodermos estableciendo una línea base de especies identificadas. Se registraron in situ un total de 17 ,766 individuos pertenecientes a 10 especies de equinodermos; para la clase Echinoidea: 1 especie; Clase Ophiuroidea: 2 especies; Clase Holothutoidea: 3 especies; Clase Asteroidea: 4 especies. La especie E. vambrunti fue la más representativa con un total de 11 ,744 ejemplares. Los parámetros ambientales tomados fueron pH, salinidad y oxígeno, pese a tener relación con los organismos no influyen en su presencia; los resultados presentaron una baja riqueza (10 especies) y una alta abundancia (17,766 organismos) que se evidenció con el promedio de 1,2 ± 0,56; el índice de uniformidad de Pielou llegó a su media estadística de 0,14, indicando que la riqueza específica de los equinodermos es independiente de la zona muestreada, obteniendo que el sitio de investigación presentó una zona con alta abundancia y baja diversidad.

Abstract: In Ecuador, the study of echinoderms has focused on protected areas (PAs), leading to new research in other rocky areas outside of a PA; The objective of this research was to describe both the composition and community structure of echinoderms by establishing a baseline of identified species. A total of 17,766 individuals belonging to ten species of echinoderms were recorded in situ, indicating; for the class Echinoidea: 1 species; the class Ophiuroidea: 2 species; the class Holothutoidea: 3 species; and the asteroid class: 4 species. The species E. vambrunti was the most representative with a total of 11,744 specimens. The environmental parameters taken where pH, salinity and oxygen, which, although related to the organisms, did not influence their presence. The results showed a low richness (10 species) and a high abundance (17,766 organisms) that is evidenced by the average of 1,2±0,56; the Pielou uniformity index reached its statistical average of 0,14, indicating that the specific abundance of echinoderms is independent of the sampled area, implying that the research site showed a high abundance and low diversity.

ABSTRACT. Sea cucumbers (holothuroids) play a major role in coastal environments; their detritivore conduct favors oxygen penetration in the sediments and the disposal of pathogens on the sea floor. This study determined holothuroid diversity in the rocky intertidal zone of Matanchén Bay, Mexico. Sampling campaigns were carried out in January, March, May, and July 2018. Linear transects (10 m length and 1 m width) perpendicular to the coastline in rocky areas (0-3 m depth) were established, where the density (ind m-2) and proportion (%) of sea cucumbers were estimated. Organisms were photographed, examined live, and preserved in 70% alcohol for subsequent identification utilizing ossicle characterization. Our results show the presence of four sea cucumber species: Holothuria (Halodeima) inornataSemper, 1868, Holothuria (Selenkothuria) lubricaSelenka, 1867, Holothuria (Selenkothuria) portovallartensisCaso, 1954, and Holothuria (Mertensiothuria) viridiaurantiaBorrero-Pérez & Vanegas-González, 2019. The average density per species was 0.208, 0.108, 0.017, and 0.025 ind m-2, respectively; each species' proportion was 58.1, 30.2, 4.7, and 7.0%, respectively. Due to the above values, we found that the number and spatial distribution of sea cucumber species vary in Matanchén Bay.

Abstract Carapace width-carapace length (CW/CLRs), carapace width-weight (CW/WRs), and carapace length-weight (CL/WR) relationships are presented for the portunid species Callinectes bocourti A. Milne Edwards, 1879, Callinectes danae Smith, 1869, and Callinectes ornatus Ordway, 1863 from the northern coast of Brazil. A total of 85 crabs were collected between May and October 2015 in intertidal zones of the Caeté, Pirabas and Salinas estuaries. All species had strong relationships between measurements with a coefficient of determination (r 2) ranging between 0.97 and 0.99. The variable most strongly related to CW was CL with 99 % of the variability provided by C. ornatus. These relationships are a useful tool for field ecologists to estimate length and/or mass of portunid species, and it is not necessary to euthanize the organism to collect body measurements. Additionally, this study describes the first reference of CW/CLRs and CL/WRs for these portunid species in the region. The Callinectes species in Amazon estuaries are still poorly studied, and there is a need for monitoring their stocks due to its importance for artisanal fishery. The present data are important for supplying biological information required for an adequate management of this fishery.

Abstract Background Animal social systems can be described through four main components: social structure, social organization, mating system, and care system. Social structure describes the relationships between individuals in a population, while social organization describes the group composition, size, and spatiotemporal variation of a population. We use the frameworks of social structure and social organization to study the social system of Microlophus atacamensis, a lizard found in the rocky intertidal zone along the Chilean coast. The area M. atacamensis inhabits poses specific challenges stemming from their use of two distinct habitat types in the intertidal zone: they forage in the cool areas near the water's edge and use large rocks in more inland areas for basking and refuge. Methods Our assessment of their social system focused on two separate populations: one to characterize social structure by means of focal observations and social network analysis, and a second to assess social organization via home range and core area analyses. Further, we examined the social system in two habitat types that comprise the intertidal zone: cobble fields and interspersed large rocks. Results Social network analysis revealed an interconnected network with a few highly central individuals. Body size influenced the outcomes of aggressive interactions, with interactions being more common in cobble fields where males had more associates and more repeated interactions than females. Spatial analyses revealed that the social organization of M. atacamensis is characterized by (1) high home range overlap, specifically in the cobble fields and (2) relatively exclusive core areas dispersed across both habitat types. Conclusion A social system is composed of both cooperative and competitive behaviors. While our study focused on competitive interactions, the extent and influence of cooperative behaviors is still unclear and merits future research. We suggest that M. atacamensis has a variable social system in which territoriality on large rocks affects access to stationary resources in that habitat (e.g., basking sites and refuges), while competition in the cobble fields could lay the foundation for a system of dominance relationships controlling access to variable food resources in cobble field areas of the intertidal zone.

ABSTRACT In this paper, the natural distribution pattern of modern bone remains in different parts of the Moat Bay coastal area is analyzed. The purpose of this analysis is to assess the areas with ahigher probability of bone remains accumulation and dispersion, and to generate expectationsabout the integrity of archaeological sites. Additionally, the natural modifications that occur onthe cortical surface of bones are evaluated. Results show that intertidal zone dynamics has adissimilar effect in bone assemblage formation, and that theseprocesses have different impact leveldepending on location and coastal landform type. Furthermore, different taphonomic trajectoriesfor birds and mammals were identified. Results allow predicting the integrity level of the siteslocated in the environmental contexts under study and provide valuable decision-making toolsfor archaeological projects in this region.

RESUMEN Se analiza el patrón de la distribución natural de huesos actuales en los distintos sectores de la franja costera de bahía Moat. Con este fin se busca evaluar los espacios donde existen mayores posibilidades de acumulación y dispersión de restos óseos y de generar expectativas sobrela integridad de los sitios arqueológicos. Asimismo, se evalúan las modificaciones naturales quese producen en la superficie cortical de los huesos. Los resultados muestran que la dinámicadel intermareal actúa de manera disímil en la formación de los conjuntos óseos y que dichosprocesos impactan en diferentes grados según la ubicación y la geoforma costera. Además, seidentificaron distintas trayectorias tafonómicas para las aves y los mamíferos. Los resultadospermiten predecir el grado de integridad de los sitios ubicados en los contextos ambientales aquíestudiados y constituyen herramientas valiosas para tomar decisiones en el marco de proyectosarqueológicos regionales.

Resumo O objetivo principal deste estudo foi investigar as variações sazonais de peixes e crustáceos em relação à composição taxonômica, riqueza de espécies e diversidade no habitat de praias arenosas. Para esse fim, investigamos a área da lagoa Sonmiani Hor durante quatro estações distintas, ou seja, monção nordeste (NE), pré-monção, monção sudoeste (SW) e pós-monção, por um ano. Durante cada transporte, a rede foi puxada cerca de 100 m ao longo da praia, a 0,5 m de profundidade. Os resultados mostraram uma forte correlação linear entre o índice de diversidade e a equitabilidade de peixes (r = 0,978). O índice de diversidade apresentou forte correlação negativa com a abundância e a biomassa (r = -0,978 e -0,972, respectivamente). Os atributos físicos, como temperatura da água da superfície do mar e salinidade, apresentaram forte efeito negativo sobre o conjunto de espécies (r = -0,981 e -0,943, respectivamente). A temperatura média do ar e da água teve uma diferença de aproximadamente 3 °C durante a monção NE e a pré-monção. No entanto, salinidade, pH e condutividade elétrica não apresentaram variabilidade sazonal significativa. A respeito dos índices ecológicos, as espécies de peixes apresentaram maior diversidade (H’ = 3,19) durante a monção SW, enquanto a menor diversidade observada foi na pré-monção (H’ = 1,58). A equitabilidade e a riqueza de espécies, no entanto, permaneceram mais perceptíveis durante a monção SW (J’ = 0,81). O número total de peixes e crustáceos foi de 4.799, com 3.813 peixes e 986 crustáceos. Foram registradas 27 famílias de peixes e 5 famílias de crustáceos, com 30 gêneros e 38 espécies de peixes, além de 10 gêneros e 17 espécies de crustáceos. Liza subviridis apresentou a maior abundância entre as espécies de peixes amostradas. Em conclusão, as espécies de peixes constituíram uma parte significativa da fauna costeira na área de estudo. As variações sazonais apresentaram variações distintas na composição e diversidade das espécies de peixes.

Abstract The primary objective of this study was to investigate the seasonal fish and crustacean variations concerning taxonomic composition, species richness, and diversity in sandy beach habitat. For this purpose, we investigated the Sonmiani Hor lagoon area during four distinct seasons, i.e., northeast (NE) monsoon, pre-monsoon, south-west (SW) monsoon, and post-monsoon for one year. During each haul, the net was pulled about 100m along the beach in 0.5m depth. The results showed a strong linear correlation between the diversity index and equitability in fishes (r = 0.978). The diversity index was strong negatively correlated with the abundance and biomass (r = -0.978, -0.972, respectively). The physical attributes like sea surface water temperature and salinity showed a strong negative effect on species assemblages (r = -0.981 and -0.943, respectively). The mean air and water temperature illustrated approximately 3°C difference during NE and pre-monsoon seasons. However, salinity, pH, and electrical conductivity did not show any significant seasonal variabilities. Under the ecological indices, the fish species displayed higher diversity (H’ = 3.19) during SW monsoon, whereas the lowest diversity was observed during pre-monsoon (H’ = 1.58). The equitability and species richness, however, remained more noticeable during SW monsoon (J’ = 0.81). The total number of individuals of fish and crustaceans reached 4799 with 3813 fish individuals and 986 individuals of crustaceans. A total of 27 families of fish while five crustacean families comprising of 30 genera and 38 fish species while ten genera and 17 species of crustaceans were recorded. Liza subviridis displayed the highest abundance among the sampled fish species. In conclusion, fish species constituted a significant part of the coastal fauna in the study area. The seasonal variations displayed distinct variations in fish species composition and diversity.

Resumen Introducción: El intermareal rocoso constituye un paisaje marino costero dominante en el Pacífico Tropical Oriental, albergando comunidades biológicas altamente diversas y funcionalmente complejas. El conocimiento sobre la diversidad y los diversos procesos biológicos que ocurren en tales ambientes es, no obstante, bastante limitado a escala regional. Objetivo: Cuantificar, describir y comparar (a escala regional) la diversidad ictiológica asociada al intermareal rocoso del Área de Conservación Guanacaste (ACG), Costa Rica, así como evaluar y discutir algunos patrones biogeográficos y ecológicos. Métodos: Entre 2014 y 2019 se muestrearon un total de 49 pozas de marea en siete ubicaciones dentro del ACG. Se obtuvieron datos sobre diversidad absoluta (presencia/ausencia de especies), además de algunos datos ecológicos (estatus de residencia, estadio(s) de desarrollo, gremio trófico, hábitos de agrupación y crípticos y distribución generalizada) los cuales se compararon con datos publicados de otros estudios/inventarios llevados a cabo en diversas localidades (20) a lo largo de la costa del Pacífico Oriental. Por medio de un análisis de similitud se evaluaron posibles patrones de agrupamiento entre localidades (según su composición de especies) y, bajo una perspectiva biogeográfica, hipótesis previas de regionalización. Resultados: Se registraron un total de 67 especies de peces óseos asociadas al intermareal rocoso del ACG, siendo la localidad con datos publicados, más diversa a nivel del Pacífico Oriental. En el ACG los componentes/categorías transitorio con 30 especies (44.8 %), juveniles con 38 especies (55.9 %), carnívoros con 47 especies (70.1 %), solitarios con 32 especies (47.8 %) y endémico del PTO con 66 especies (98 %), fueron dominantes. A nivel regional se recopilaron datos para un total de 246 especies. Los resultados del análisis de similitud soportaron el esquema de división biogeográfico, definido a priori, a nivel regional, con las localidades ubicadas dentro de las provincias Californiana, Cortez, Mexicana, Panámica y Peruana-Chilena recuperadas como grupos altamente consistentes. Esta estructura es consecuente con el efecto de barreras como las brechas arenosas de Sinaloa y Centroamericana, entre otras, limitando el flujo de especies entre unidades biogeográficas. Conclusiones: El ACG presenta una elevada diversidad ictiológica asociada a su intermareal rocoso producto de una combinación de factores única a nivel regional. Los resultados de este estudio refuerzan además la necesidad de realizar más estudios básicos y aplicados a diferentes escalas local y regional con el objetivo de ayudar a comprender y conocer mejor diversos aspectos clave de la dinámica y procesos físico-químico-biológicos ocurriendo en las zonas intermareales, de su riqueza biológica asociada, de su importancia dentro del paisaje marino-costero como un continuo y de las posibles afectaciones que estos podrían sufrir debido al impacto de las actividades humanas.

Abstract Introduction: The rocky intertidal constitutes a dominant coastal seascape in the Eastern Tropical Pacific, harboring highly diverse and functionally complex biological communities. The knowledge about the diversity and the diverse biological processes that occur in such environments is, however, quite limited on a regional scale. Objective: Quantify, describe and compare (on a regional scale) the ichthyological diversity associated with the rocky intertidal zone of the Guanacaste Conservation Area (ACG), Costa Rica, as well as to evaluate and discuss some biogeographic and ecological patterns. Methods: A total of 49 tide pools were sampled between 2014 and 2019, at seven locations within the ACG. Data on absolute diversity (presence/absence of species) were obtained, in addition to some ecological data (residence status, development stage (s), trophic guild, aggregation and cryptic habits and generalized geographic distribution), these data were compared with published records from other surveys/inventories carried out at various locations (20) along the Eastern Pacific coast. Through a similarity analysis, both possible clustering patterns between localities (according to their species composition) and previous hypotheses of regionalization, under a biogeographic perspective, were evaluated. Results: A total of 67 species of bony fish were recorded in the rocky intertidal area of the ACG, being this the most diverse locality (with published data) in the Eastern Pacific. The components/categories “transitory” with 30 species (44.8 %), “juveniles” with 38 species (55.9 %), “carnivores” with 47 species (70.1 %), “solitary” with 32 species (47.8 %) and “endemic to the ETP” with 66 species (98 %), were dominant (in terms of the total number of species) within the ACG. The results of the similarity analysis supported the biogeographic division scheme, defined a priori; with the localities within the Californian, Cortez, Mexican, Panamic and Peruvian-Chilean provinces recovered as highly consistent groups. This structure is consistent with the effect of barriers such as the sandy gaps of Sinaloa and Central America, among others, limiting the flow of species between biogeographic units. Conclusions: The ACG has a high ichthyological diversity associated with its rocky intertidal zone, which is product of a unique combination of factors at the regional level. The results of this study reinforce the need to carry out more basic and applied studies with the aim of helping to better understand and know different key aspects of the dynamics and physical-chemical-biological processes occurring in intertidal zones, of its associated biological diversity, of its importance within the marine-coastal landscape as a continuum and of the possible effects that these environments could suffer due to the impact of human activities.