Tropical Eastern Pacific Region Research Articles

Octocoral Distribution Patterns at the Equatorial Front (Tropical Eastern Pacific): Muricea and Leptogorgia

The Equatorial Front, in the southern part of the Tropical Eastern Pacific (TEP) region, has been characterized as a hotspot of functional biodiversity due to the mixing of warm and cold waters. Nevertheless, the biogeographic patterns for some organisms, such as octocorals, remain unknown in some coastal regions. Therefore, we aimed to assess the distribution of two common octocoral genera in this area, Muricea and Leptogorgia, including 14 species based on museum specimen records, along the mainland coast of Ecuador. Statistical analyses were performed on the environmental and geographical patterns (Sea Surface Temperature (SST), bathymetry, chlorophyll (CHL-a), and Photosynthetic Active Radiation (PAR)) that influence the Equatorial Front, which is subdivided into five biogeographic regions. Our results showed two hotspots of octocoral biodiversity. The SST was found to be the main environmental factor related to octocoral distribution along the Equatorial Front. Finally, the highest abundance of Muricea over Leptogorgia suggests the former species’ higher resilience to thermal fluctuations. We discuss the possible role of substrates at suitable depths, active photosynthetic radiation, and temperature in the occurrence of octocorals in the two hotspots.

Tasas de crecimiento somático de tortuga carey, Eretmochelys imbricata, en el Parque Nacional Natural Gorgona, Colombia, entre 2004 y 2018

La tortuga carey, Eretmochelys imbricata, se encuentra a nivel global en peligro crítico de extinción, y la información demográfica en el Océano Pacífico Oriental es limitada. Por esta razón, esta investigación evalúa las tasas de crecimiento somático en una agregación de individuos inmaduros de tortuga carey empleando el método de captura-marca-recaptura en los arrecifes coralinos de Playa Blanca y la Azufrada en el Parque Nacional Natural Gorgona, Colombia. Entre 2004 y 2018 se realizaron 89 capturas de 49 individuos de tortuga carey. El largo curvo del caparazón promedio (LCC) obtenido fue de 41,6 cm (rango 32-58 cm) y el largo recto del caparazón promedio (LRC) fue de 39,1 cm (rango 30,0-54,1 cm), lo que muestra que estos arrecifes son áreas de forrajeo importantes para individuos inmaduros de esta especie. El índice de condición corporal promedio fue de 1,3 (rango 1,0-1,5). Esto sugiere que las condiciones ambientales mantienen en buen estado la salud de esta agregación. Usando el modelo de crecimiento de von Bertalanffy y estableciendo una talla máxima (L∞) de 63 cm de LCC (donde se obtiene el menor coeficiente de variación), se estimó una k de 0,081 y una tasa anual de crecimiento promedio de 1,5 ± 1,8 cm/año. Esto indica que los individuos en esta agregación estarían alcanzando una LCC de 63 cm entre los 33 y 34 años, talla cercana a la de madurez sexual en la región del Pacífico oriental (aproximadamente 66 cm LCC). Lo anterior ratifica la vulnerabilidad de esta especie debido a las lentas tasas de crecimiento somático y madurez sexual tardía. Se sugiere que los esfuerzos de conservación para esta especie deben ser a largo plazo para procurar su recuperación, en vista de que especies con estas características tienden a expresar tasas de crecimiento poblacional muy bajas.

Historical and contemporary habitat use of sperm whales around the Galápagos Archipelago: Implications for conservation

Abstract Sperm whales have occupied the waters off the Galápagos Islands, Ecuador, for at least the past 200 years. During the 19th century, they were the target of intensive whaling that severely depleted the population. In recent times, after commercial whaling ended, sperm whales in the region remain vulnerable to multiple threats, especially potential entanglement in fishing gear, which may hinder their ability to recover from the whaling era. As a highly mobile, long‐lived species, long‐term analysis of the habitat use of sperm whales is necessary to establish effective conservation and management strategies. Here, contemporary (1985–2014) and historical (1830–1850) sperm whale habitat use off the Galápagos Islands was analysed and contrasted to the extent of the Galápagos Marine Reserve (GMR). Contemporary habitat use and its variability over time were modelled as a function of geographic, oceanographic, and topographic variables using generalized additive models. The fine‐scale habitat (<50 km) used by sperm whales was associated with topographic (i.e. depth and slope) and oceanographic characteristics (i.e. relative sea surface temperature and standard deviation of sea surface temperature), but these preferences varied over time. While historical and contemporary data indicate that sperm whale habitat primarily occurred within the boundaries of the GMR, in recent years, whales were found up to 30.1% of the time outside the GMR, potentially overlapping with commercial fisheries operating in the area. The dynamic nature of the relationship of this nomadic species with its habitat highlights the need of large‐scale conservation efforts across the Eastern Tropical Pacific region, including the wide‐scale enforcement of regulations requiring the use of Automatic Identification System in fishing vessels, the promotion of on‐board fisheries observer programmes, the development of adaptive management strategies, and international collaboration to identify and mitigate threats.

Fish diversity divergence between tropical eastern pacific and tropical western Atlantic coral reefs

A comparison of fish diversity was carried out among 45 sites within four localities in the Mexican Tropical Western Atlantic (TWA) and Tropical Eastern Pacific (TEP) regions. Several taxonomical and functional diversity indices were considered, and their relationships with the coral cover were investigated in each locality. We found that despite a lower number of species, the localities within the Mexican TEP region had equal or even higher functional diversity than the localities in the Mexican TWA region where sites within the Caribbean Sea appeared particularly poorly diversified. Divergent relationships between fish diversity and coral cover were observed between the two oceanic regions. On the one hand, it tended to be positive in the TWA, and on the other hand, it was negative in the two TEP localities. This contrast may be explained by the low coral species richness and the homogeneous habitat (low structural complexity) provided by a high cover of coral in the TEP. This study highlighted how the fish assemblages can be functionally diversified within the TEP, a region generally considered poorly diversified, and how the relationship between fish diversity and coral cover may vary between oceanic regions.

Molecular Phylogenetics of Trapezia Crabs in the Central Mexican Pacific

To date, Trapezia spp. crabs have been considered obligate symbionts of pocilloporid corals. They protect their coral hosts from predators and are essential for the health of certain coral species. However, the basic details of this group of crustaceans are lacking, and there is a need for species-level molecular markers. The Tropical Eastern Pacific (TEP) region harbors important coral communities mainly built by corals of the genus Pocillopora, with three known Trapezia species known to associate with them: Trapezia bidentata, T. formosa and T. corallina. Both taxonomic and molecular analyses were carried out with samples of all three crab species collected from Pocillopora spp. in the Central Mexican Pacific. Analysis of both a mitochondrial and a nuclear gene revealed only two species, T. corallina and T. bidentata. T. formosa however appears to be a morphotype of T. bidentata. The use of integrative taxonomy for this group has increased the knowledge of the biodiversity not only of the study area, but of the whole TEP and will enhance the future study of the Trapezia–Pocillopora symbiosis.

Molecular identification of Haemosporidia in avian endemics of Gorgona Island within a context for the eastern tropical Pacific region

Island bird populations and their obligate blood parasites are of interest for understanding the accumulation of biodiversity and the evolutionary relationship with their mainland congeners. We examined avian Haemosporidia cytochrome b gene among terrestrial birds on Gorgona Island National Park, Colombia. Three Haemoproteus haplotype groups found on Gorgona Island have a higher genetic similarity to Haemoproteus found in the eastern tropical Pacific than those documented in Africa, Asia, Europe and Oceania. Two of the haplotype groups on the island are generalists in terms of infecting multiple hosts and their wide geographical distribution within the eastern tropical Pacific region, a third Haemoproteus haplogroup appears endemic to Gorgona Island. The overall prevalence of haemosporidian parasites is 57,9% for birds on Gorgona island, which is higher than local reports of prevalence documented in other archipelagos or the mainland. The island population of Cyanerpes cyaneus gigas seems to be the most susceptible to Haemoproteus infection when compared to Thamnophilus atrinucha gorgonae and Coereba flaveola gorgonae. Our findings support an ubiquitous pattern of endemism among organisms including avian haemosporidian parasites on Gorgona Island and also highlight the potential exposure of island bird populations to avian malaria.

Habitat mapping of remote coasts: Evaluating the usefulness of lightweight unmanned aerial vehicles for conservation and monitoring

Unmanned aerial vehicles (UAVs) have the potential to be an important tool providing low-cost but sufficiently precise mapping products to support environmental management. In this study, we present possible applications of UAVs to map and monitor three representative coastal tropical habitats: mangroves, rocky shores and coral reefs. We conducted UAVs surveys in a Marine Protected Area (MPA) of the tropical eastern Pacific region to investigate the suitability and usefulness of using this tool in a remote area for a variety of management and monitoring purposes. For mangrove ecosystems, we evaluated the potential of UAV-derived data to estimate canopy cover. On an intertidal rocky shore, we evaluated the potential of UAVs to obtain a detailed relative topographic position index that can be used to correlate the distribution patterns of resident and transient fauna. Finally, we compared the standard diver-based coral reef mapping approach used at the MPA with the use of a map produced with the UAV. Our results suggest that the use of UAVs by conservation practitioners in MPAs with diverse habitats, such as in the tropics, is likely to improve the knowledge of the MPAs environments and provide highly detailed information for monitoring helping to understand the nursery function of these inter-connected tropical habitats, at a reduced cost. This tool, therefore, has the potential to support conservation measures in a more effective way.

Mangroves in the Galapagos: Ecosystem services and their valuation

Mangroves provide many benefits to human welfare, but they are disappearing rapidly; Ecuador and countries within the Tropical Eastern Pacific (TEP) region have lost over 40% of their mangrove coverage in the last 40 years. One reason for this destruction is that the benefits of mangroves have not been valued in a way that policymakers and markets can understand. Here, we present the first economic valuation of multiple ecosystem services (ES) for Ecuador and the TEP using the Galapagos mangroves as a case study. We focused on three ES of high value and policy relevance: carbon storage, support for small-scale fisheries, and mangrove-based tourism. Our data suggest that over 778,000 tons of carbon are stored in Galapagos mangroves, with mean belowground carbon being 211.03 ± 179.65 Mg C/ha, valued at $2940/ha or $22,838/ha depending on the valuation methodology. We identified mangrove-dependent fish targeted by the local finfish fishery, with net benefits of $245 ha−1, making this fishery the second most profitable in the Archipelago. The value of mangrove-based recreation was estimated at $16,958/ha, contributing $62 million to the industry. By accounting for stakeholders and existing property rights, our results allow for the discussion of institutionalizing ES payments for the Galapagos Islands.

Spatial and temporal changes in reef fish assemblages on disturbed coral reefs, north Pacific coast of Costa Rica

AbstractBenthic structure of coral reefs determines the availability of refuges and food sources. Therefore, structural changes caused by natural and anthropogenic disturbances can have negative impacts on reef‐associated communities. During the 1990s, coral reefs from Bahía Culebra were considered among the most diverse ecosystems along the Pacific coast of Costa Rica; however, recently they have undergone severe deterioration as consequence of chronic stressors such as El Niño‐Southern Oscillation and harmful algal blooms. Reef fish populations in this area have also been intensely exploited. This study compared reef fish assemblages during two periods (1995–1996 and 2014–2016), to determine whether they have experienced changes as a result of natural and anthropogenic disturbances. For both periods, benthic composition and reef fish abundance were recorded using underwater visual censuses. Live coral cover (LCC) decreased from 43.09 ± 18.65% in 1995–1996 to 1.25 ± 2.42% in 2014–2016 (U = 36, p < 0.05). Macroalgal cover (%) in 2014–2016 was sixfold higher than mean values reported for the Eastern Tropical Pacific region. Mean (±SD) fish species richness in 1995–1996 (36.67 ± 14.20) was higher than in 2014–2016 (23.00 ± 9.14; U = 20, p < 0.05). Over 40% of reef fish orders observed in 1995–1996 were not detected in the 2014–2016 surveys, including large‐bodied predators. Reduction in abundance of fish predators such as sharks, grunts, and snappers is likely attributed to changes in habitat structure. Herbivorous such as parrotfishes and pufferfishes increased their abundance at sites with low LCC, probably in response to predators decline and increased algal cover. These findings revealed significant degradation and drastic loss of structural complexity in coral reefs from Bahía Culebra, which now are dominated by macroalgae. The large reduction in structural complexity of coral reefs has resulted in the loss of diversity and key ecological roles (e.g., predation and herbivory), thus potentially reducing the resilience of the entire ecosystem.

Pacific Decadal Oscillation: Tropical Pacific Forcing versus Internal Variability

The Pacific decadal oscillation (PDO) is the leading mode of sea surface temperature (SST) variability over the North Pacific (north of 20°N). Its South Pacific counterpart (south of 20°S) is the South Pacific decadal oscillation (SPDO). The effects of tropical eastern Pacific (TEP) SST forcing and internal atmospheric variability are investigated for both the PDO and SPDO using a 10-member ensemble tropical Pacific pacemaker experiment. Each member is forced by the historical radiative forcing and observed SST anomalies in the TEP region. Outside the TEP region, the ocean and atmosphere are fully coupled and freely evolve. The TEP-forced PDO (54% variance) and SPDO (46% variance) are correlated in time and exhibit a symmetric structure about the equator, driven by the Pacific–North American (PNA) and Pacific–South American teleconnections, respectively. The internal PDO resembles the TEP-forced component but is related to internal Aleutian low (AL) variability associated with the Northern Hemisphere annular mode and PNA pattern. The internal variability is locally enhanced by barotropic energy conversion in the westerly jet exit region around the Aleutians. By contrast, barotropic energy conversion is weak associated with the internal SPDO, resulting in weak geographical preference of sea level pressure variability. Therefore, the internal SPDO differs from the TEP-forced component, featuring SST anomalies along ~60°S in association with the Southern Hemisphere annular mode. The limitations on isolating the internal component from observations are discussed. Specifically, internal PDO variability appears to contribute significantly to the North Pacific regime shift in the 1940s.

Assessment of the stock status of small-scale and multi-gear fisheries resources in the tropical Eastern Pacific region

Small-scale multi-gear fisheries contribute half of global fisheries landings but are generally data-poor, hindering their assessment and management. Aiming to overcome various existing challenges, we used two complementary length-based approaches to assess the status of three main target species in the small-scale fisheries of Eastern Pacific countries: Spotted rose snapper Lutjanus guttatus, Pacific sierra Scomberomorus sierra, and Pacific bearded Brotula clarkae, using length-frequency catch data (LFCD) from the Colombian Pacific coast. Two data sources – official governmental data and community-based monitoring from a non-government organization – were used to estimate two sets of stock indicators: one based on the derivation of growth and mortality parameters from modal progression, catch curve analysis and a yield-per-recruit model using TropFishR; and the second based on the relative contribution of fish sizes with regard to proposed reference values for healthy stocks. Growth estimates differed between data sources and exhibited large confidence intervals, indicating an overall high uncertainty underlying the LFCD revealed through a novel bootstrapped approach. Estimated values of stock indicators, exploitation rate, fishing mortality and size-proportions converged in suggesting a state of heavy to over-exploitation for the three assessed species, although differences were observed among data sources that we attribute mainly to fisheries selectivity and sampling design. In order to improve future assessments of stocks in multi-gear and data-poor contexts, estimations of fleet-specific selectivity should be used to reconstruct LFCD prior to analyses. Additionally, sampling design should be based on fishing effort distribution among gears and areas and, when feasible, fishery-independent data on stock conditions should be included.

Composición taxonómica y abundancia espacio-temporal de la ictiofauna del Río Presidio, Sinaloa, México

Taxonomic composition and spatio-temporal abundance of the ichthyofauna in Presidio River, Sinaloa, Mexico. The Rio Presidio in the southern Sinaloa, Mexico belongs to Nearctic-Neotropical zoogeographical transition zone, where its fish fauna could manifest changes in the abundance and distribution of the species during rainy and dry periods. The main objective of this study was to describe the taxonomic composition and spatial and temporal abundance of the fish fauna from the lower and middle Rio Presidio, by means of bimonthly samplings from April 2008 to February 2009. Forty fish species (39 native and 1 exotic) belonging to 32 genera and 19 families were registered. Two families (Gerreidae and Poeciliidae) contained the highest numbers of species (five and four, respectively). Six species (Lile stolifera, Oreochromis aureus, Awaous banana, Anchoa analis, Gobiomorus maculatus and Atherinella crystallina) in this order of importance contributed with almost 49 % of the total fish abundance. Species richness and salinity showed a direct relationship and an inverse relationship with the altitude. Based on the coefficient of similarity of species among sites two fish assemblages were identified. The first assemblage formed by species from marine derivation (peripheral) occurring in the lower part of the river, and the second assemblage by secondary freshwater species in the middle part. The higher fish species similarity observed in August and September was under the influence of the highest flows of the rainy period. Twenty-seven 27 species showed affinity to the Tropical Eastern Pacific Region, six species to the Neotropical region and two to the Nearctic region (Dorosoma smithi and Ictalurus cf. pricei ); one species has an Amphiatlantic distribution (Mugil curema), another is circumtropical (Mugil cephalus), two species have Amphiamerican distribution (A. monticola and G. cinereus), and one is exotic (O. aureus). Rev. Biol. Trop. 66(2): 848-862. Epub 2018 June 01.

Using landing statistics and fishers’ traditional ecological knowledge to assess conservation threats to Pacific goliath grouper in Colombia

Abstract Groupers are vulnerable to fishing pressure largely because of their life‐history traits. The Pacific goliath grouper (PGG; Epinephelus quinquefasciatus), the largest reef fish inhabiting the tropical Eastern Pacific region, is suspected to be subject to high levels of exploitation, but scarce information exists on their population status and the species remains classed as Data Deficient according to the International Union for Conservation of Nature (IUCN) Red List. This study documents for the first time the threats to the PGG along the Colombian Pacific coast, where one of the few active fisheries for this species persists. Reconstructed landings of groupers and traditional ecological knowledge, gathered throughout several coastal villages, were used to obtain a historical and contemporary overview of the PGG status in Colombia. Over the past 20 years grouper landings in the Colombian Pacific have been around 200 tons per year. Landings of PGG have averaged ~35 tons per year and are now close to matching those of the historically most landed grouper on this coast, the rooster hind (Hyporthodus acanthistius). The current small‐scale fishery for PGG focuses on immature small individuals, with most taken from the extensive southern mangroves. Until recently fishers have captured PGG exclusively with handlines, but new fishing practices (spearfishing) and markets commanding higher prices for small individuals are increasing the extinction risk for the PGG. The exploitation of PGG in the Colombian Pacific may not be as severe as in other countries where severe population declines are suspected (e.g. Mexico). Low coastal human population density and the presence of relatively intact mangroves, essential habitat for juvenile fishes, contribute to the persistence of PGG populations throughout the Colombian Pacific. National and regional conservation and management measures should identify and protect mangrove nurseries and offshore spawning aggregation sites. Well‐enforced protected nurseries and spawning aggregation sites will then protect juvenile and adult PGG, improving the sustainability of this fishery.

Diversity and distribution of caprellids (Crustacea: Amphipoda: Caprellidae) in the Eastern Tropical Pacific region: Review of the literature

Antecedentes. Los caprelidos son de los grupos de anfipodos mas diversos y abundantes asociados a ambientes marinos, desempenan un papel fundamental en los ecosistemas como recurso energetico en diferentes niveles troficos y, sin embargo, a pesar de su importancia, su abundancia y riqueza de especies en el Pacifico oriental tropical (POT), es pobremente conocida. Objetivos . El proposito de este trabajo fue recopilar y actualizar el conocimiento existente sobre los caprelidos del POT y describir generalidades sobre su alimentacion, habitat, distribucion, reproduccion y ciclos de vida. Metodos. El trabajo se centro en la busqueda de material bibliografico acerca del POT publicado entre 1903 y 2016, mediante el buscador Google Scholar y las bases de datos Redalyc, Scielo, Science Direct e ISI Web, asi como por referencias cruzadas. Resultados. Se encontro que hasta el momento se han registrado un total de 16 especies agrupadas en cinco generos que se distribuyen principalmente entre 1 y 30 m de profundidad dentro de la zona litoral y particularmente asociados a los ecosistemas coralinos. En la ultima decada, el conocimiento sobre la riqueza de especies de caprelidos registrada incremento 65.5%. Para el POT, el 57% de los registros se han documentado en subregiones del Pacifico mexicano; lo anterior evidencia el gran vacio de informacion para el resto de las subregiones. Conclusiones. Debido a la escasa informacion y al potencial de contar con mas especies en la region, se recomienda incrementar el esfuerzo de muestreo con el fin de contribuir al conocimiento del grupo y generar una linea base de informacion para futuras investigaciones que permita mejorar las estrategias de manejo y conservacion de los ecosistemas marinos.

Diversity and distribution of caprellids (Crustacea: Amphipoda: Caprellidae) in the Eastern Tropical Pacific region: Review of the literature

Antecedentes. Los caprelidos son de los grupos de anfipodos mas diversos y abundantes asociados a ambientes ma - rinos, desempenan un papel fundamental en los ecosistemas como recurso energetico en diferentes niveles troficos y, sin embargo, a pesar de su importancia, su abundancia y riqueza de especies en el Pacifico oriental tropical (POT), es pobremente conocida. Objetivos. El proposito de este trabajo fue recopilar y actualizar el conocimiento existente sobre los caprelidos del POT y describir generalidades sobre su alimentacion, habitat, distribucion, reproduccion y ciclos de vida. Metodos. El trabajo se centro en la busqueda de material bibliografico acerca del POT publicado entre 1903 y 2016, mediante el buscador Google Scholar y las bases de datos Redalyc, Scielo, Science Direct e ISI Web, asi como por referencias cruzadas. Resultados. Se encontro que hasta el momento se han registrado un total de 16 especies agrupadas en cinco generos que se distribuyen principalmente entre 1 y 30 m de profundidad dentro de la zona litoral y particularmente asociados a los ecosistemas coralinos. En la ultima decada, el conocimiento sobre la riqueza de especies de caprelidos registrada incremento 65.5%. Para el POT, el 57% de los registros se han documentado en subregiones del Pacifico mexicano; lo anterior evidencia el gran vacio de informacion para el resto de las subregiones. Conclusiones. Debido a la escasa informacion y al potencial de contar con mas especies en la region, se recomienda incrementar el esfuerzo de muestreo con el fin de contribuir al conocimiento del grupo y generar una linea base de informacion para futuras investigaciones que permita mejorar las estrategias de manejo y conservacion de los ecosistemas marinos

Unusual reef fish biomass and functional richness at Malpelo, a remote island in the Tropical Eastern Pacific

Fish assemblages can vary across temporal and spatial scales due to changes in habitat structure and the influence of local factors such as wave exposure, depth and anthropogenic influence. This study presents a description of species richness, functional richness, density and biomass of fish assemblages of Malpelo Island, a Marine Protected Area located in the Tropical Eastern Pacific (TEP) region and considered a World Heritage site. Underwater visual censuses (n = 103) from two years and a local checklist were used to characterize the reef fish assemblage of Malpelo Island. Our results show a numerical dominance, during both sampling years, by the planktivore species Chromis atrilobata and Apogon atradorsatus, which are regional TEP endemic species. Among the most striking results found were the high biomass values (706.2 g/m2 ± 73.2 in 2010 and 879 g/m2 ± 116.2 in 2015) of large-bodied TEP endemic piscivorous species and the high functional diversity represented mainly by vulnerable species. The dominance in density and biomass of regional endemic species exemplifies the high endemism level within the TEP. High levels of fish biomass and functional richness suggest that Malpelo is one of the most pristine and vulnerable sites within the TEP region. Thus, Malpelo island represents a baseline for untouched assemblages in this marine province, as well as a priority area for conservation at the national and international level.

DNA-assisted identification of Caulerpa (Caulerpaceae, Chlorophyta) reduces species richness estimates for the Eastern Tropical Pacific

Taxonomy and species richness estimates for the genus Caulerpa have proven challenging due to the difficulty of assessing morphological species limits. In the present study we evaluate the taxonomy of the genus and assess species distributions in the Eastern Tropical Pacific (ETP), based on morphology and tufA sequence data. Molecular analyses revealed six species-level clades: C. verticillata, C. sertularioides, C. cupressoides, C. serrulata, C. racemosa and C. chemnitzia (part of C. racemosa-peltata complex). Our results reduce species richness estimates throughout the ETP by over 54% (from 13 to 6). In accordance with recent studies, our morphological and DNA results warrant the recognition of C. chemnitzia to comprise the morphological entities C. laetevirens, C. peltata and C. vanbossea complex. We continue the use of ecads as a practical identification tool for morphological diversity below the species level present in the ETP. In addition we formally recognize the synonymy of C. racemosa var. macrophysa with the lineage of C. racemosa proposed in recent studies. The six species of Caulerpa found in this study are of pantropical in distribution. Within the ETP region, four species have restricted distributions (C. verticillata, C. cupressoides, C. serrulata, C. racemosa), while two show a wide latitudinal distribution (C. chemnitzia and C. sertularioides).

Tidal and Diel Patterns in Abundance and Feeding of a Marine-Estuarine-Dependent Fish from Macrotidal Mangrove Creeks in the Tropical Eastern Pacific (Colombia)

Mangrove ecosystems are nursery habitats for several snapper species worldwide. Yet the short-term dynamics in nursery habitat use of Lutjanidae remain poorly understood, with knowledge biased toward clear water, nonestuarine mangroves. Here, we document the effects of tidal-diel cycles and salinity on patterns in abundance and feeding of the yellow snapper, Lutjanus argentiventris, using samples collected from intertidal creeks in a macrotidal estuarine mangrove during 2009–2010 from Colombia, in the Tropical Eastern Pacific (TEP) region. Abundance and biomass were significantly higher in medium salinity versus low salinity creeks. Contrasting tidal-diel patterns of abundance-densities versus catch mass-biomass were due to a size-based intraspecific variation in mangrove use: fish 20 cm entered at night during both spring and neap tides. L. argentiventris had a generalist diet (mainly fish and porcellanid crabs). Fish <10 cm displayed a narrower diet breadth than larger size classes, with decreasing importance of fish size during ontogeny. The highest stomach fullness index values (especially of individuals <20 cm) during neap tide-daytime inundations contradicted the common assumption that snappers are nocturnal feeders and highlight the role of tidal-diel cycles in determining fish feeding preferences in macrotidal mangrove systems. Comparisons with other studies showed that habitat use and feeding patterns of this and other Lutjanids vary significantly according to size, tidal-diel dynamics, and mangrove settings, e.g., marine microtidal versus estuarine macrotidal systems. Therefore, generalized conclusions derived from a single mangrove setting should be drawn with caution.

Calls of Bryde's whale (Balaenoptera edeni) recorded in the Gulf of California (L).

A total of 109 recordings aiming to identify Bryde's whale calls were collected from the Gulf of California, Mexico, during field trips performed from January 2010 to June 2014. Vocalizations were recorded only when no calves were observed. Four types of calls were identified. Calls similar to the Be4 call type previously reported for the Eastern Tropical Pacific region and South of California were recorded. In addition, three calls, not reported in previous studies of the Bryde's whale, have also been identified. The identification of these calls, which were labeled Be10, Be11, and Be12, enables expansion of the known acoustic repertoire of this species, which is currently poorly documented. The identification of three previously unreported calls and the confidence given by careful visual confirmation of the whale species and number of individuals contribute to make this study a significant contribution toward the acoustic monitoring of Bryde's whale.

Annual rings in a native Hawaiian tree,Sophora chrysophylla, on Maunakea, Hawaiʻi

Abstract:Annual rings are not commonly produced in tropical trees because they grow in a relatively aseasonal environment. However, in the subalpine zones of Hawaiʻi's highest volcanoes, there is often strong seasonal variability in temperature and rainfall. Using classical dendrochronological methods, annual growth rings were shown to occur inSophora chrysophylla, a native tree species on Maunakea, Hawaiʻi. Chronologies were established from nearby non-native, live conifer trees and these were used to verify the dates from a total of 52 series from 22S. chrysophyllatrees, establishing an 86-y chronology (1926–2011). Ring-width patterns were significantly correlated with monthly rainfall from August of the previous year. This study is the first in the eastern tropical Pacific region to demonstrate annual growth rings in trees.