Reproductive biology of Donax striatus (Linnaeus, 1758) (Mollusca: Bivalvia) on Gado Bravo Beach, municipality of Tibau do Norte, state of Rio Grande do Norte, Brazil.

Aspects of the reproductive biology of Donax striatus were studied from individuals collected from Gado Bravo Beach in the municipality of Tibau do Norte, state of Rio Grande do Norte, Brazil. Donax striatus is a dioic species without external (on the shell) or internal (gonads) macroscopic dimorphism. Thus, a microscopic examination of the reproductive cells is necessary. For the characterization of the gonadal development stages and determination of the size at first sexual maturity (L50), 30 specimens were selected monthly between February 2021 and January 2022 and submitted to histological processing. The condition index (CI) of each individual was estimated and monthly variations were statistically assessed. The size at first maturity (L50) was estimated to be 14.2 mm in shell length. To foster conservation of the species, catches of individuals larger than 14.2 mm is recommended. The lowest condition indices were found in the dry season, with a greater occurrence of organisms in the elimination stage and exhibiting gonad tissue reorganization. Higher indices were found in the rainy season, with the presence of mature individuals. The continuous nature of gametogenesis in Donax stritatus reflects the influence of rainfall in the region. Males and females have peak gamete elimination with pauses during the year, but with the presence of maturing and eliminating individuals throughout the year. As shellfish gathering targeting Donax striatus is excessive on Gado Bravo Beach in the state of Rio Grande do Norte, it is hoped that the results of the present study can contribute to the establishment of management measures for the activity and conservation strategies for the species.

Thyasirid species composition (Bivalvia: Thyasiridae) and genetic connectivity of Parathyasira equalis (A. E. Verrill & K. J. Bush, 1898) in deep basins of sub-Arctic fjords.

BACKGROUND: Thyasirid bivalves are often recorded as a dominant component of macrobenthic infaunal communities in depositional environments such as fjord basins. Fjord basins comprise patchy soft-bottom habitats bounded by steep walls and sills; however, little is known how this semi-isolated nature of fjords affects benthic populations. Accordingly, data on the composition and population connectivity of thyasirids can provide valuable information on the ecology of these ecosystems. RESULTS: The species composition of thyasirid bivalves has been studied in the basins of three sub-Arctic fjords (Nordland, Northern Norway). Overall, six thyasirid species were recorded: Parathyasira equalis, Parathyasira dunbari, Mendicula ferruginosa, Genaxinus eumyarius, Thyasira sarsii, and Thyasira obsoleta. The species composition remained stable within the basins during the sampling period (2013-2020) and suggested the importance of local reproduction over advection of individuals for population dynamics. Only one species, Parathyasira equalis, was common in all fjords. We have further investigated the population genetics of this species by combining two types of genetic markers: a 579 bp fragment of the cytochrome c oxidase subunit I (COI) gene and 4043 single-nucleotide polymorphisms (SNPs) generated by genotyping-by-sequencing. The latter provided a more in-depth resolution on the population genetics of this species and revealed a weak but significant differentiation of populations within fjords, further indicating limited connectivity between basins. CONCLUSION: Based on our findings, we conclude that limited dispersal between the basin communities results in weakly connected populations and might be an important structuring factor for macrobenthic communities.

Doubling the known diversity of a remote island fauna: marine bivalves of the Juan Fernández and Desventuradas oceanic archipelagos (Southeastern Pacific Ocean).

Juan Fernández and Desventuradas are two oceanic archipelagos located in the southeastern Pacific Ocean far off the Chilean coast that received protected status as marine parks in 2016. Remoteness and access difficulty contributed to historically poor biodiversity sampling and limited associated research. This is particularly noticeable for bivalves, with most prior regional publications focused on single taxa or un-illustrated checklists. This study investigates marine bivalves collected between the intertidal and 415 m depth during (1) the 1997 IOC97 expedition aboard the M/V Carlos Porter, with special focus on scuba-collected micro-mollusks of both archipelagos, (2) two expeditions by the R/V Anton Bruun (Cruise 12/1965 and Cruise 17/1966), and (3) Cruise 21 of USNS Eltanin under the United States Antarctic Program, which sampled at Juan Fernández in 1965. Also, relevant historical material of the British H.M.S. Challenger Expedition (1873-1876), the Swedish Pacific Expedition (1916-1917), and by German zoologist Ludwig H. Plate (1893-1895) is critically revised. A total of 48 species are recognized and illustrated, including 19 new species (described herein) and six other potentially new species. The presence of two species mentioned in the literature for the region (Aulacomya atra and Saccella cuneata) could not be confirmed. The genera Verticipronus and Halonympha are reported for the first time from the Eastern Pacific, as are Anadara and Condylocardia from Chilean waters. Lectotypes are designated for Arca (Barbatia) platei and Mytilus algosus. These findings double the number of extant bivalve species known from the Juan Fernández and Desventuradas archipelagos, highlighting the lack of attention these islands groups have received in the past. A high percentage of species endemic to one or both archipelagos are recognized herein, accounting for almost 78% of the total. The newly recognized level of bivalve endemism supports the consideration of Juan Fernández and Desventuradas as two different biogeographic units (Provinces or Ecoregions) of the Eastern Pacific Ocean.

Structure, Evolution, and Mitochondrial Genome Analysis of Mussel Species (Bivalvia, Mytilidae).

Based on the nucleotide sequences of the mitochondrial genome (mitogenome) of specimens taken from two mussel species (Arcuatula senhousia and Mytilus coruscus), an investigation was performed by means of the complex approaches of the genomics, molecular phylogenetics, and evolutionary genetics. The mitogenome structure of studied mussels, like in many other invertebrates, appears to be much more variable than in vertebrates and includes changing gene order, duplications, and deletions, which were most frequent for tRNA genes; the mussel species' mitogenomes also have variable sizes. The results demonstrate some of the very important properties of protein polypeptides, such as hydrophobicity and its determination by the purine and pyrimidine nucleotide ratio. This fact might indirectly indicate the necessity of purifying natural selection for the support of polypeptide functionality. However, in accordance with the widely accepted and logical concept of natural cutoff selection for organisms living in nature, which explains its action against deleterious nucleotide substitutions in the nonsynonymous codons (mutations) and its holding of the active (effective) macromolecules of the polypeptides in a population, we were unable to get unambiguous evidence in favor of this concept in the current paper. Here, the phylogeny and systematics of mussel species from one of the largest taxons of bivalve mollusks are studied, the family known as Mytilidae. The phylogeny for Mytilidae (order Mytilida), which currently has no consensus in terms of systematics, is reconstructed using a data matrix of 26-27 mitogenomes. Initially, a set of 100 sequences from GenBank were downloaded and checked for their gender: whether they were female (F) or male (M) in origin. Our analysis of the new data confirms the known drastic differences between the F/M mitogenome lines in mussels. Phylogenetic reconstructions of the F-lines were performed using the combined set of genetic markers, reconstructing only protein-coding genes (PCGs), only rRNA + tRNA genes, and all genes. Additionally, the analysis includes the usage of nucleotide sequences composed of other data matrices, such as 20-68 mitogenome sequences. The time of divergence from MRCA, estimated via BEAST2, for Mytilidae is close to 293 Mya, suggesting that they originate in the Silurian Period. From all these data, a consensus for the phylogeny of the subfamily of Mytilinae and its systematics is suggested. In particular, the long-debated argument on mussel systematics was resolved as to whether Mytilidae, and the subfamily of Mytilinae, are monophyletic. The topology signal, which was strongly resolved in this paper and in the literature, has refuted the theory regarding the monophyly of Mytilinae.

New records of non-indigenous species from the eastern Mediterranean Sea (Crustacea, Mollusca), with a revision of genus Isognomon (Mollusca: Bivalvia).

We report new data on non-indigenous invertebrates from the Mediterranean Sea (four ostracods and 20 molluscs), including five new records for the basin: the ostracods Neomonoceratina iniqua, Neomonoceratina aff. mediterranea, Neomonoceratina cf. entomon, Loxoconcha cf. gisellae (Arthropoda: Crustacea)-the first records of non-indigenous ostracods in the Mediterranean-and the bivalve Striarca aff. symmetrica (Mollusca). Additionally, we report for the first time Electroma vexillum from Israel, and Euthymella colzumensis, Joculator problematicus, Hemiliostraca clandestina, Pyrgulina nana, Pyrgulina microtuber, Turbonilla cangeyrani, Musculus aff. viridulus and Isognomon bicolor from Cyprus. We also report the second record of Fossarus sp. and of Cerithiopsis sp. cf. pulvis in the Mediterranean Sea, the first live collected specimens of Oscilla galilae from Cyprus and the northernmost record of Gari pallida in Israel (and the Mediterranean). Moreover, we report the earliest records of Rugalucina angela, Ervilia scaliola and Alveinus miliaceus in the Mediterranean Sea, backdating their first occurrence in the basin by 3, 5 and 7 years, respectively. We provide new data on the presence of Spondylus nicobaricus and Nudiscintilla aff. glabra in Israel. Finally, yet importantly, we use both morphological and molecular approaches to revise the systematics of the non-indigenous genus Isognomon in the Mediterranean Sea, showing that two species currently co-occur in the basin: the Caribbean I. bicolor, distributed in the central and eastern Mediterranean, and the Indo-Pacific I. aff. legumen, at present reported only from the eastern Mediterranean and whose identity requires a more in-depth taxonomic study. Our work shows the need of taxonomic expertise and investigation, the necessity to avoid the unfounded sense of confidence given by names in closed nomenclature when the NIS belong to taxa that have not enjoyed ample taxonomic work, and the necessity to continue collecting samples-rather than relying on visual censuses and bio-blitzes-to enable accurate detection of non-indigenous species.

[Structure and Evolution of DNA Transposons of the L31 Superfamily in Bivalves].

The mobile genetic elements IS630/Tc 1/mariner (ITm) are widespread DNA transposons that make a significant contribution to the evolution of eukaryotic genomes. With the start of large-scale application of next-generation sequencing (NGS) technologies and the emergence of many new whole genome sequences of organisms in nucleotide sequence collections, the ITm elements have been identified in most taxa of the eukaryotic tree of life. Although ITm diversity has been studied in detail, new elements are still found, thus expanding the respective DNA transposon group and calling for review of its classification. Bivalve L31 elements were for the first time analyzed in detail to describe their structures, diversity, distribution, and phylogenetic position among the ITm elements. The L31 transposons were found to form an independent superfamily of an ancient origin within the ITm group. Rather high diversity was observed within the L31 clade; i.e., five phylogenetic clusters were identified. In mollusks, the L31 transposons have been detected only in the subclass Autobranchia and predominate in diversity and number in the infraclass Pteriomorphia. A protein encoded by open reading frame 2 (ORF2) was shown to be an integral structural component of almost all full-length L31 elements. The results provide for a better understanding of the evolution of particular ITm transposons. Further study of the L31 transposons in other taxa (cnidarians) and functional investigation of the ORF2 protein product will help to better understand the evolution of DNa transposons, the mechanisms of their horizontal transfer, and their contribution to eukaryotic biodiversity.

Testing ultraconserved elements (UCEs) for phylogenetic inference across bivalves (Mollusca: Bivalvia).

Bivalves constitute an important resource for fisheries and as cultural objects. Bivalve phylogenetics has had a long tradition using both morphological and molecular characters, and genomic resources are available for a good number of commercially important species. However, relationships among bivalve families have been unstable and major conflicting results exist between mitogenomics and results based on Sanger-based amplicon sequencing or phylotranscriptomics. Here we design and test an ultraconserved elements probe set for the class Bivalvia with the aim to use hundreds of loci without the need to sequence full genomes or transcriptomes, which are expensive and complex to analyze, and to open bivalve phylogenetics to museum specimens. Our probe set successfully captured 1,513 UCEs for a total of 263,800 bp with an average length of 174.59 ± 3.44 per UCE (ranging from 28 to 842 bp). Phylogenetic testing of this UCE probe set across Bivalvia and within the family Donacidae using different data matrices and methods for phylogenetic inference shows promising results at multiple taxonomic levels. In addition, our probe set was able to capture large numbers of UCEs for museum specimens collected before 1900 and from DNAs properly stored, of which many museums and laboratories are well stocked. Overall, this constitutes a novel and useful resource for bivalve phylogenetics.

Growth and production of Donax striatus(Bivalvia: Donacidae) from Las Balsas beach, Gibara, Cuba / Crecimiento y producción de Donax striatus (Bival-via: Donacidae) en playa Las Balsas, Gibara, Cuba

Abstract:Clams of the genus Donaxare worldwide the dominating group of the invertebrate community on sandy beaches. They are primary consumers that provide a significant abundance and biomass to the ecosystem. In the Caribbean, Donax striatushas an important role for nature and human, nonetheless studies on the population dynamics of this beach clam are scarce and no information exists on secondary production of this species. Growth parameters and secondary production of D. striatuswere estimated from February 2008 to November 2009 at Las Balsas beach, Northeastern Cuba, in order to provide basic information for management purposes. In each month 45 samples were taken by means of a PVC corer of 0.025 m2 area and sieved with a 1 mm mesh. Animals were measured and weighted with and without shell. A total of 5 471 specimens were collected during the sampling period. Shell length ranged from 2.7-33.3 mm. Growth parameters estimated from length frequency data were Lm = 36.1 mm, K= 0.8/yr and t0 = 0.2/yr. The growth performance resulted in values of 0'= 3.02. Life span was 2.4 yrs and mortality rate was 3.07 /yr. In 2008, mean abundance of D. striatusranged between 17.1770.7 ind./m2. In 2009 the lowest mean abundance was 34.4 and the highest was 892.5 ind./m2. During 2009 biomass and production was more than twice higher in comparison with 2008. Individual production showed highest values in the 24 mm shell size (3.74 g/m2.yr) and 25 mm (0.71 g/m2.yr), considering mass with shell and without shell, respectively. During 2009 abundance of individuals with 15 mm shell length or more increased resulting in higher biomass and production, compared to 2008. Using the conversion factor of wet mass to ash free dry mass (AFDM), annual production ranged between 2.87-6.11 g AFDM/m2.yr, resulting in a turnover rate (P/B) between 5.11 and 3.47 in 2008 and 2009, respectively. The rapid growth and high turnover rate of D. striatussuggest a rapid recovery of the population. These results support the idea that this beach clam is an important resource at Las Balsas beach. Thus its exploitation must continue with caution, and only at the level of a recreational fishery.

Resumen:Los estudios sobre la dinámica poblacional de la almeja de playa Donax striatusson escasos y no existe información sobre la producción secundaria de alguna población de esta especie. Los parámetros del crecimiento y la producción secundaria de D. striatusfueron estimados a partir de datos de muestreo obtenidos entre febrero 2008 y noviembre 2009 en playa Las Balsas en la zona norte oriental de Cuba para aportar información básica para su manejo. Cada mes se recolectaron 45 muestras usando un núcleo de PVC de 0.025 m2, el sedimento fue tamizado en malla de 1 mm. Los individuos recolectados fueron medidos y pesados con concha y sin concha. La longitud de la concha fue de 2.7-33.3 mm. Los parámetros de crecimiento estimados a partir de las frecuencias de tallas fueron: Lm= 36.1 mm, K= 0.8/año y t0 = 0.2/año. El índice de crecimiento fue de 0'= 3.02. El tiempo de vida estimado de 2.4 años y la mortalidad 3.07/año. En 2008 la abundancia media de D. striatusfluctuó entre de 17.1-770.7 ind/m2. En 2009 la menor abundancia fue de 34.4 y la mayor de 892.5 ind/ m2. En 2009 la biomasa y la producción fueron más del doble que las estimadas en 2008. La mayor producción somática individual fue aportada por individuos de 24 mm (3.74 g/m2.año) y 25 mm (0.71 g/m2.año), considerando la masa total con concha y sin concha respectivamente. Durante 2009 la abundancia de individuos de 15 mm de longitud o más, se incrementó resultando en mayor bio-masa y producción en comparación con 2008. Usando el factor de conversión de peso húmedo a peso seco libre de cenizas (PSLC), la producción anual en 2008 fue de 2.87 y en 2009 fue 6.11 g PSLC/m2.año, lo que resulta en una tasa de renovación (P/B) de 5.11 en 2008 y 3.47 en 2009. Estos resultados apoyan la idea que la almeja de playa es un recurso importante y su explotación debe continuar con cautela y solo a un nivel de una pesquería recreativa.

Estructura de la población y distribución de Anadara tuberculosa Sowerby (1833) (Mollusca: Bivalvia) en los manglares de Golfito y Playa Blanca de Puerto Jiménez, Golfo Dulce, Costa Rica / Population structure and distribution of Anadara tuberculosa Sowerby (1833) (Mollusca: Bivalvia) in the mangroves of Golfito and Playa Blanca, Puerto Jiménez, Golfo Dulce, Costa Rica

Resumen El presente estudio describe la dinámica de la población del bivalvo Anadara tuberculosa conocido en Costa Rica como piangua, en varios manglares de Golfito y Playa Blanca de Puerto Jiménez, Golfo Dulce en la costa Pacífica de Costa Rica. El estudio está basado en varios muestreos realizados mensualmente durante el periodo 2008-2010. A cada individuo recolectado se midió la longitud, el peso total y el peso fresco para calcular variables como el rendimiento, densidad y distribución de esta especie. La población de pianguas en los manglares de Golfito presentó mayor densidad (2.77 individuos/m2) que el manglar de Playa Blanca (0.14 individuos/m2). Se observó que los individuos de Playa Blanca presentaron mayor longitud (48.35mm) que los reportados para los manglares de Golfito (42.51mm), este último valor, por debajo del mínimo de extracción estipulado por Ley. Playa Blanca presentó también el mayor peso total (36.35g) que Golfito (24.48g). Este aumento del peso total en los individuos de Playa Blanca incide en que el rendimiento de la carne en este manglar resulte menor (17.01%) que en Golfito (23.45%). Los resultados sugieren que la población de A. tuberculosa puede encontrase en estado de reducción en estos manglares y por consiguiente, es necesario implementar proyectos de repoblamiento de este molusco en los manglares del Golfo Dulce, en conjunto con proyectos de manejo en una acción en conjunto con las autoridades gubernamentales responsables, organizaciones no gubernamentales y la Sociedad Civil, para hacer de esta especie un recurso que sea sostenible y aprovechada por diferentes actores de la comunidad.

Abstract The density, population, length, yield and sex proportion of the Anadara tuberculosa Sowerby (1833) were studied in the mangroves of Golfito and Playa Blanca, Golfo Dulce, Costa Rica from 2008-2010. A. tuberculosa was more abundant in Golfito mangroves (2.77 units m2), than Playa Blanca mangrove (0.14 units m2). The average lengths were 42.1mm for Golfito (under the Costa Rican legal minimal length for exploitation: 47mm) and 48.35mm for Playa Blanca mangrove. Maximum densities in Golfito were measured in the outlet of Purruja River (mangrove of Purruja) and mangroves Congo, Ceibo y la Trocha. The average total weights were 24.48g for Golfito and 36.35g for Playa Blanca. The condition index (a meat yield measurement) was higher in Golfito (23.45%) than in Playa Blanca (17.01%). The male ratio was 1:1. These results suggest that A. tuberculosa population is declining in these mangroves. Therefore, it's necessary to implement repopulation projects of the mollusc in the mangroves of Golfo Dulce, in conjunction with government authorities, NGOs and civil society. Mangrove workers and consumers are needed in that potential projects, to make the mollusc a sustainable natural resource exploited by different community members. Rev. Biol. Trop. 63 (Suppl. 1): 287-298. Epub 2015 April 01.

Bio-filtration capacity, oxygen consumption and ammonium excretion of Dosinia ponderosa and Chione gnidia (Veneroida: Veneridae) from areas impacted and non-impacted by shrimp aquaculture effluents / Bio-filtración, consumo de oxígeno y excreción amoniacal de Dosinia ponderosa y Chione gnidia (veneroida: veneridae), en áreas impactadas y no impactadas por efluentes de granjas camaroneras

Mollusks are some of the most important, abundant and diverse organisms inhabiting not only aquatic ecosystems, but also terrestrial environments. Recently, they have been used for bioremediation of aquaculture effluents; nevertheless, for that purpose it is necessary to analyze the capacity of a particular species. In this context, an experimental investigation was developed to evaluate the performance of two bivalves C. gnidia and D. ponderosa, collected from areas with or without shrimp aquaculture effluents. For this, the filtration capacity (as clearance rate) as well as the oxygen consumption and ammonia excretion rates were measured following standard methods. The clearance rate was significantly higher for D. ponderosa from impacted areas, when com- pared to C. gnidia, from both areas. Contrarily, the oxygen consumption was greater for C. gnidia from impacted areas compared to D. ponderosa from both areas. The same tendency was observed for the ammonia excretion with the highest rates observed for C. gnidia from impacted areas, whereas no differences were observed among D. ponderosa from both areas. The results suggest that both species developed different strategies to thrive and survive under the impacted conditions; D. ponderosa improved its filtration efficiency, while C. gnidia modified its oxygen consumption and ammonia excretion. We concluded that both species, and particularly D. ponderosa, can be used for bioremediation purposes.

Los moluscos son algunos de los organismos más importantes, abundantes y diversos que habitan no solo ecosistemas acuáticos sino también terrestres. Recientemente ellos han sido utilizados para la biorremediación de efluentes acuícolas; para este propósito, es necesario conocer la capacidad de especies particulares que funcionan como biorremediadores. En este contexto, se evaluó la eficiencia de filtración (medida como tasa de clarificación), así como las tasas de consumo de oxígeno y excreción amoniacal en los bivalvos D. pon- derosa y C. gnidia recolectados en áreas impactadas y no impactadas por efluentes de granjas camaroneras. La tasa de clarificación fue mayor para D. ponderosa procedente de áreas impactadas, comparada con la de C. fluctifraga en las dos áreas de recolecta. Contrariamente, la tasa de consumo de oxígeno fue superior en C. gnidia en las áreas impactadas al compararla con organismos de áreas no impactadas y con D. ponderosa de las dos áreas de recolecta. La tasa de excreción amoniacal siguió una tendencia similar con valores más altos para C. gnidia en áreas impactadas, mientras que no se observaron diferencias para D. ponderosa entre las áreas de recolecta. Los resultados sugieren que ambas especies desarrollan diferentes estrategias para adaptarse y sobrevivir bajo condiciones de impacto; D. ponderosa mejora su eficiencia de filtración y C. gnidia modifica su consumo de oxígeno y excreción amoniacal. Se concluye que ambas especies, pero sobre todo D. ponderosa pueden ser utilizadas con propósitos de biorremediación.

Molecular markers for genetic diversity, gene flow and genetic population structure of freshwater mussel species / Marcadores moleculares para estudo da diversidade genética, fluxo génico e estrutura genética de populações de espécies de mexilhões de água doce

Freshwater mussel species are in global decline. Anthropogenic changes of river channels and the decrease of autochthonous fish population, the natural hosts of mussels larval stages (glochidia), are the main causes. Therefore, the conservation of mussel species depends not only on habitat conservation, but also on the availability of the fish host. In Portugal, information concerning most of the mussel species is remarkably scarce. One of the most known species, Unio pictorum is also in decline however, in the basins of the rivers Tua and Sabor (Northeast of Portugal), there is some indication of relatively large populations. The aforementioned rivers can be extremely important for this species conservation not only in Portugal, but also in the remaining Iberian Peninsula. Thus, it is important to obtain data concerning Unio pictorum bioecology (distribution, habitat requirements, population structure, genetic variability, reproductive cycle and recruitment rates), as well as the genetic variability and structure of the population. Concomitantly, information concerning fish population structure, the importance of the different fish species as “glochidia” hosts and their appropriate density to allow effective mussel recruitment, will also be assessed. The achieved data is crucial to obtain information to develop effective management measures in order to promote the conservation of this bivalve species, the conservation of autochthonous fish populations, and consequently the integrity of the river habitats.

As espécies de mexilhões de água doce estão em declínio global. Mudanças antropogénicas do canal dos rios e diminuição das populações de peixes autóctones, os hospedeiros naturais do mexilhão nos estágios larvais (glochidia), são as principais causas. Portanto, a conservação de espécies de mexilhão depende não só da conservação dos habitats, mas também da disponibilidade do hospedeiro peixe. Em Portugal, a informação relativa à maioria das espécies de mexilhão é extremamente escassa. Uma das espécies mais conhecidas, Unio pictorum também está em declínio, no entanto, nas bacias dos rios Tua e Sabor (Nordeste de Portugal), existe indicação de populações relativamente grandes. Os rios acima mencionados podem ser extremamente importantes para a conservação das espécies, não só em Portugal, mas também na restante Península Ibérica. Assim, é importante obter dados relativos à bioecologia do Unio pictorum (distribuição, requisitos de habitat, estrutura populacional, variabilidade genética, ciclo reprodutivo e as taxas de recrutamento), bem como a variabilidade e estrutura genética da população. Concomitantemente, informações sobre a estrutura da população de peixes, a importância das diferentes espécies de peixes como hospedeiros e sua densidade adequada para permitir o recrutamento eficaz do mexilhão, também será avaliada. Os resultados obtidos serão cruciais para obter informações que permitam o desenvolvimento de medidas de gestão eficazes, a fim de promover a conservação destas espécies de bivalves, a conservação das populações de peixes autóctones e, consequentemente, a integridade dos habitats fluviais.

Three invasive species occurring in the diets of fishes in a Neotropical floodplain / Ocorrência de três espécies invasoras nas dietas de peixes em uma planície de inundação Neotropical

The composition of the diets of 66 species of fishes was investigated from September 2009 to June 2010 in three subsystems of the Upper Paraná River floodplain (Brazil), following invasion by the two mollusk species Limnoperna fortunei (Dunker, 1857) and Corbicula fluminea (Müller, 1774), and the macrophyte Hydrilla verticillata (L.f.) Royle. Limnoperna fortunei was consumed in all three subsystems and occurred in the diet of 15 fish species, with a high proportion in the diet of Leporinus obtusidens. Corbicula fluminea was present in the diet of Pterodoras granulosus caught in the Paraná and Ivinheima subsystems. Hydrilla verticillata occurred in the diet of Schizodon nasutus caught in the Ivinheima and Paraná subsystems. It is not yet possible to evaluate the potential of these species to control invasive mollusks in the study area or the impact of these species on the structure of the food chain. Omnivorous and herbivorous fishes in the study area may have little impact on the population of H. verticillata.

A composição da dieta de 66 espécies de peixes foi investigada de setembro de 2009 a junho de 2010, em três subsistemas da planície de inundação do alto rio Paraná (Brasil), após a invasão das espécies de molusco Limnoperna fortunei (Dunker, 1857) e Corbicula fluminea (Müller, 1774), e da macrófita Hydrilla verticillata (L.f.) Royle. Limnoperna fortunei foi consumida em todos os subsistemas amostrados e ocorreu na dieta de 15 espécies de peixes, com grande participação na dieta de Leporinus obtusidens. Corbicula fluminea esteve presente na dieta de Pterodoras granulosus coletados nos subsistemas Paraná e Ivinheima. Hydrilla verticillata ocorreu na dieta de Schizodon nasutus, capturados nos subsistemas Ivinheima e Paraná. Até o momento não é possível avaliar o potencial destas espécies para controlar moluscos invasores na área de estudo ou o impacto destas espécies sobre a estrutura das cadeias alimentares. Peixes omnívoros e herbívoros da área de estudo podem ter pouco impacto sobre a população de H. verticillata.

Intra-specific variability in life-history traits of Anadara tuberculosa (Mollusca: Bivalvia) in the mangrove ecosystem of the Southern coast of Ecuador / Variaciones en la historia de vida de Anadara tuberculosa (Mollusca: Bivalvia) en el ecosistema de manglar de la costa Sur de Ecuador

Anadara tuberculosa is one of the most important bivalves along the Western Pacific coast because of its commercial value. Nevertheless, the variability in growth, longlife span, natural mortality and reproductive parameters of this mangrove cockle has not yet been described. The aim of this study was to analyze these lifehistory traits in three areas of the Southern coast of Ecuador. Empirical and length-based methods were used to estimate these biological parameters. Body size data were collected from the commercial fishery between 2004 and 2011 in landing ports near to the Archipelago of Jambeli [Puerto Bolivar (PB), Puerto Jeli (PJ) and Puerto Hualtaco (PH)]. The von Bertalanffy growth parameters for combined sex were estimated between 70.87 to 93.45mm for L∞ and 0.22 to 0.80/year for k. The growth indices (Φ’) ranged from 3.17 to 3.85, while the overall growth performance (OGP) ranged from 5.03 to 5.82. The mean of long-life span (t max), size and age at maturity (L50% and t50%) were estimated in 7.71±2.53years, 39.13±2.24mm and 1.46±0.56years for PB; 9.51±2.85years, 37.78±1.95mm and 1.37±0.41years for PJ and 5.81±2.11years, 39.73±3.31mm and 0.94±0.41years for PH. Natural mortality (M) ranged from 0.46 to 1.28/year. We concluded that significant intra-specific variation was observed in a temporal scale in Φ’ and OGP indices as well as L50% and M. Therefore, temporal changes in these life-history traits should be taken into account when assessing the status of the mangrove cockle fishery.

La pesquería de la concha prieta (Anadara tuberculosa) es una de las más importantes a lo largo de la costa del Pacifico. Las variaciones intra-especificas en el crecimiento, longevidad, mortalidad natural y parámetros reproductivos de la concha prieta, aún no han sido descritas. Por lo tanto, el objetivo de este estudio fue analizar esos parámetros biológicos en tres áreas al Sur de Ecuador. Métodos empíricos y basados en tallas fueron empleados para estimar los parámetros de historia de vida. Los datos de tallas analizados correspondieron al periodo 2004-2011 y son provenientes del muestreo de los desembarques de los puertos adyacentes al Archipiélago de Jambeli [Puerto Bolivar (PB), Puerto Jeli (PJ) y Puerto Hualtaco (PH)], al Sur de Ecuador. Los parámetros de crecimiento oscilaron entre 70.87 y 93.45mm de L∞ y 0.22 a 0.80/año de k. Mientras que los índices de crecimiento entre 3.17 a 3.85 de Φ’ y 5.03 a 5.82 de OGP. Los valores promedio de longevidad (t max), talla y edad de madurez (L50% y t50%) fueron de 7.71±2.53años, 39.13±2.24mm y 1.46±0.56años en PB; 9.51±2.85años, 37.78±1.95mm y 1.37±0.41años en PJ y de 5.81±2.11años, 39.73±3.31mm y 0.94±0.41años en PH. Las estimaciones de mortalidad natural (M) oscilaron entre 0.46 y 1.28/año. Importantes cambios intra -especificos se observaron a escala temporal tanto en los índices Φ’ y OGP, así como en L50% y M. Por lo tanto, se sugiere considerar las variaciones temporales en los parámetros biológicos de A. tuberculosa, al momento de caracterizar el estatus de su pesquería y más aun si es sometida a altos niveles de extracción.

Estructura comunitaria de bivalvos y gasterópodos en raíces del mangle rojo Rhizophora mangle (Rhizophoraceae) en isla Larga, bahía de Mochima, Venezuela / Community structure of bivalves and gastropods in roots of red mangrove Rhizophora mangle (Rhizophoraceae) in isla Larga, Mochima Bay, Venezuela

The Rhizophora mangle roots form a complex ecosystem where a wide range of organisms are permanently established, reproduce, and find refuge. In this study, we assessed the diversity of bivalves and gastropods that inhabit red mangrove roots, in isla Larga, Mochima, Venezuela Sucre state. Bimonthly collections were made from January 2007 to May 2008, in four study areas denominated: South, North, East and West. In each area, five mangrove roots were sampled, and the specimens were obtained. We analyzed a total of 180 roots and a total of 35 bivalve species and 25 gastropod species were found. The most abundant bivalves were: Isognomon alatus, Isognomon bicolor, Ostrea equestris, Crassostrea rhizophorae and Brachidontes exustus; among gastropods, the most common where: Littorina angulifera, Cymatium pileare and Diodora cayenensis. The months with the highest abundances and number of individuals for both groups were January and July 2007, and March 2008. The mangrove ecosystem in isla Larga, presented a number of individuals and species higher than those reported for other regions in Venezuela and the Caribbean. Rev. Biol. Trop. 62 (2): 551-565. Epub 2014 June 01.

Las raíces del mangle rojo forman un complejo ecosistema donde se reproducen, refugian y establecen de manera permanente una gran diversidad de organismos. En este estudio, se evaluó la diversidad de bivalvos y gasterópodos que habitan las raíces del mangle rojo Rhizophora mangle, en isla Larga, Bahía de Mochima, estado Sucre Venezuela. Se realizaron recolectas bimensuales desde enero 2007 hasta mayo 2008, en cuatro zonas de estudio denominadas: zona sur, norte, este y oeste. En cada zona se muestrearon cinco raíces de mangle, de donde se obtuvieron los especímenes. Se analizaron un total 180 raíces y se contabilizaron 35 especies de bivalvos y 25 de gasterópodos. Los bivalvos más abundantes fueron: Isognomon alatus, Isognomon bicolor, Ostrea equestris, Crassostrea rhizophorae y Brachidontes exustus, mientras que los gasterópodos más frecuentes: Littorina angulifera, Cymatium pileare y Diodora cayenensis. Los meses donde se observaron las mayores abundancias de especies y número de individuos fueron enero y julio 2007 y marzo 2008. El ecosistema de manglar en isla Larga, presentó un número de individuos y especies superior al reportado en otros trabajos realizados en Venezuela y otras regiones del Caribe.

Modelación del crecimiento individual del callo de hacha Atrina maura (Bivalvia: Pinnidae) a partir de la inferencia multi modelo / Individual growth modeling of the penshell Atrina maura (Bivalvia: Pinnidae) using a multi model inference approach

Growth models of marine animals, for fisheries and/or aquaculture purposes, are based on the popular von Bertalanffy model. This tool is mostly used because its parameters are used to evaluate other fisheries models, such as yield per recruit; nevertheless, there are other alternatives (such as Gompertz, Logistic, Schnute) not yet used by fishery scientists, that may result useful depending on the studied species. The penshell Atrina maura, has been studied for fisheries or aquaculture supplies, but its individual growth has not yet been studied before. The aim of this study was to model the absolute growth of the penshell A. maura using length-age data. For this, five models were assessed to obtain growth parameters: von Bertalanffy, Gompertz, Logistic, Schnute case 1 and Schnute and Richards. The criterion used to select the best models was the Akaike information criterion, as well as the residual squared sum and R² adjusted. To get the average asymptotic length, the multi model inference approach was used. According to Akaike information criteria, the Gompertz model better described the absolute growth of A. maura. Following the multi model inference approach the average asymptotic shell length was 218.9mm (IC 212.3-225.5) of shell length. I concluded that the use of the multi model approach and the Akaike information criteria represented the most robust method for growth parameter estimation of A. maura and the von Bertalanffy growth model should not be selected a priori as the true model to obtain the absolute growth in bivalve mollusks like in the studied species in this paper.

El molusco bivalvo Atrina maura (Sowervy 1835) habita aguas marinas someras y estuarios en la costa del Pacífico desde Baja California, México hasta Perú. Es un organismo cuyo crecimiento individual ha sido insuficientemente modelado. El objetivo del estudio fue modelar su crecimiento individual absoluto mediante el uso de datos de longitud a la edad obtenidos de una región del Golfo de California. Los parámetros fueron obtenidos con el uso de cinco modelos de crecimiento; von Bertalanffy, Gompertz, Logístico, Caso 1 de Schnute y Schnute & Richards. Se seleccionó el mejor modelo usando el criterio de información de Akaike, AIC, pero se calcularon también la suma de residuos al cuadrado y la R² ajustada. Para obtener la longitud asintótica se siguió el enfoque de inferencia multi modelo IMM. Según el AIC el modelo que mejor describe el crecimiento absoluto de A. maura es el de Gompertz y colocó en cuarto lugar jerárquico el de von Bertalanffy. La longitud asintótica promedio encontrada, siguiendo la IMM, fue de 218.9mm (IC 212.3-225.5) de longitud de concha. Se concluye que tanto la IMM como el AIC representan las herramientas más sólidas para evaluar parámetros de crecimiento individual de A. maura y que el modelo de crecimiento de von Bertalanffy no debe ser seleccionado a priori como la opción para describir el crecimiento individual en moluscos bivalvos como la especie estudiada.

Composición y estructura de la macrofauna asociada con agregaciones de dos especies de bivalvos en Isla de Cubagua, Venezuela / Composition and structure of the macrofauna associated with beds of two bivalve species in Cubagua Island, Venezuela

Bivalve aggregations constitute a microhabitat for a wide variety of organisms in intertidal, subtidal and deep-water marine benthic habitats. Increase in density of bivalve beds could offer more crevices and substratum for the associated fauna, affecting community composition. Beds of the Atlantic Pearl Oyster (Pinctada imbricata) and the Turkey Wing (Arca zebra) of contrasting population densities were evaluated to determine the composition and structure of the associated macrofauna of three taxa (Crustacea Decapoda, Mollusca and Echinodermata). We evaluated plots of three levels of bed density in both species, the associated fauna were identified and counted. Other species were collected by qualitative samples. Univariate and multivariate descriptors were tested comparing the associated fauna between the beds of two species at three levels of density. In these beds a total of 104 species belonging to 58 families were recorded. Mithraculus forceps (Majidae), Crucibulum auricula (Calyptraeidae) and Ophiotrix angulata (Ophiothrichidae) were the most common species found in these assemblages. The medium and high-density bivalve beds exhibited greater species number, abundance, Shannon diversity, evenness, taxonomic diversity, and taxonomic distinctness of associated fauna, than low-density bivalve beds. Moreover, multivariate analysis detected different assemblages of associated fauna between beds with different densities. Additionally, similarities were found in the communities of macrofauna in both beds of P. imbricata and Arca zebra. Our results suggest that bivalve aggregations at Cubagua Island provide additional habitat for macrofauna living in other shallow habitats such as Thalassia beds, corals and rocky environments. Bed density, associated with topographic complexity, represents an important factor for the composition and complexity of the associated fauna.

Las agregaciones de bivalvos constituyen un microhábitat para una gran variedad de organismos en el ambiente intermareal, submareal y en aguas profundas. Agregaciones de la ostra perla (Pinctada imbricata) y pepitona (Arca zebra) a diferentes densidades poblacionales se evaluaron para determinar la composición y estructura comunitaria de la macrofauna asociada en tres taxa (Crustacea Decapoda, Mollusca y Echinodermata). La hipótesis nula de no diferencias en descriptores univariados y multivariados fue probada comparando la fauna asociada entre las agregaciones de las dos especies a tres niveles de densidad. En estas agregaciones se identificaron 102 especies de 55 familias. Mithraculus forceps (Majidae), Crucibulum auricula (Calyptraeidae) y Ophiotrix angulata (Ophiothrichidae) fueron las especies más comunes encontradas en estas asociaciones. Las densidades medias y altas de las agregaciones de bivalvos presentaron mayor número de especies, abundancia, diversidad de Shannon, equidad, diversidad taxonómica y distinción taxonómica de la fauna asociada que las agregaciones de baja densidad poblacional. Análisis multivariados detectaron diferentes estructuras de los ensambles de la fauna asociada en agregaciones de bivalvos con densidad baja en comparación con los de densidad media y alta. Adicionalmente no se detectaron diferencias en la fauna asociada entre las especies. La densidad de las agregaciones de bivalvos, asociada a la complejidad topográfica, es un factor importante para la composición de la fauna asociada.

The reproductive biology of Lutraria philippinarum (Veneroida: Mactridae) and its fishery in the Philippines

The Snout Otter Clam, Lutraria philippinarum is a regularly harvested bivalve species for food and also as a source of income in the Philippines. For sustainable supply of this resource in the wild, efficient and effective management strategies are needed, and the evaluation of its reproductive biology and fishery are required. In this study, the reproductive biology and fishery of L. philippinarum in the Philippines were examined monthly from January to December 2010 in North Bais Bay, Manjuyod, Negros Oriental and Philippines. For reproductive biology, otter clams were sampled, and sex ratio (by microscopic observation), size at sexual maturity, shell length (with a vernier caliper), gonad development (by histological examination as resting, developing, mature, spawning and spent) and spawning season were determined. Other information such as water temperature, salinity, pH and dissolved oxygen were also measured. To obtain information on the L. philippinarum fishery, interviews were conducted in Negros Oriental, Bohol, Cebu and Sarangani. A total of 677 snout otter clams were sampled. The study showed that L. philippinarum sex ratio was 1:1.15 and showed no significant difference from 1:1 ratio. Males attained its first sexual maturity at 43mm shell length while the females at 46mm. Histological examination on gonad development indicated that gametogenesis, maturation and spawning season of L. philippinarum occurred throughout the year with two spawning peaks, January and June. Changes in water temperature in North Bais Bay may have influenced the spawning peaks of L. philippinarum. Data on the fishery of L. philippinarum revealed that the Catch Per Unit Effort of L. philippinarum in the Philippines ranged from 0.2kg/hr-man to 1.25kg/hr-man suggesting low shell catch. We recommend that some mature individuals have to be left in the population to allow in situ breeding.

Lutraria philippinarum es una especie de bivalvo recolectada regularmente para la alimentación y como fuente de ingreso en las Filipinas. Para el suministro sostenible de este recurso en la naturaleza, se necesitan estrategias de manejo efectivas, así como la evaluación de su biología reproductiva y pesquera. Se examinaron estos aspectos mensualmente de enero-diciembre 2010 en North Bais Bay, Manjuyod, Negros Oriental, Filipinas. Se tomó medida del tamaño a la madurez sexual, proporción de sexos (con observación microscópica), longitud de la concha (con calibrador vernier), desarrollo de gónadas (con examinación histológica del descanso, desarrollo, madurez, desove y gasto) y época de desove. Para obtener información de la pesquería de L. philippinarum, se realizaron entrevistas en Negros Oriental, Bohol, Cebu y Sarangani. Un total de 677 ostras fueron muestreadas. Se encontró que la proporción de sexos fue 1:1.15 y no se observó diferencia significativa de la proporción 1:1. Los machos alcanzaron la madurez sexual a la longitud de concha de 43mm mientras que las hembras a 46mm. El análisis histológico del desarrollo de las gónodas indicó que la gametogénesis, maduración y desove ocurren durante todo el año con dos picos de desove, enero y junio. Los datos sobre la pesquería revelaron que la captura por unidad de esfuerzo de L. philippinarum osciló entre 0.2kg/h hombre a 1.25kg/h hombre que sugieren baja captura de conchas. Recomendamos que algunos individuos maduros tienen que ser dejados en la población para permitir la reproducción in situ.

Reproductive cycle of Tagelus plebeius (Mollusca: Bivalvia) in the estuary of the Cachoeira River, Ilhéus, Bahia, Brazil / Ciclo reprodutivo de Tagelus plebeius (Mollusca: Bivalvia) no estuário do Rio Cachoeira, Ilhéus-Bahia, Brasil

This study characterized the reproductive cycle of the stout razor clam Tagelus plebeius in the estuary of the Cachoeira River, Ilhéus, Bahia, northeastern Brazil. Samples of 20 animals per collection were taken biweekly from August 2005 to August 2006. The 480 specimens were measured on the antero-posterior axis (length) and then removed from the shell. After macroscopic analysis, the gonads were fixed in Davidson's solution, processed by routine histology and stained by Harris hematoxylin and eosin. The gonads of both males and females appeared milky white, without sexual dimorphism. Microscopic analyses indicated a M: F ratio of 1.06: 1 and continuous reproduction of T. plebeius in the region. The period from August to October showed the most intense spawning. This study provides another example of continuous reproduction of bivalves in tropical waters, and because this species is a heavily exploited fishery resource in the region, it draws attention to the need for a management plan aimed at reducing harvests.

Neste estudo, objetivou-se caracterizar o ciclo reprodutivo de Tagelus plebeius na região estuarina do Rio Cachoeira, Ilhéus-Bahia. As amostragens, 20 animais/coleta, foram feitas quinzenalmente, entre agosto de 2005 e agosto de 2006. Os 480 animais, depois de medidos quanto ao seu eixo ântero-posterior (comprimento), foram removidos da concha e, após análise macroscópica, as gônadas foram fixadas em solução de Davidson, processadas por técnica rotineira de histologia e coradas com hematoxilina de Harris e eosina. As gônadas de machos e fêmeas apresentaram aspecto branco leitoso e não houve dimorfismo sexual. As análises microscópicas evidenciaram razão sexual M:F de 1,06:1 e reprodução contínua de T. plebeius na região. O período entre agosto e outubro foi caracterizado como o de maior eliminação de gametas. O estudo fornece outro exemplo de reprodução contínua de bivalves em regiões tropicais e, por ser um recurso pesqueiro intensamente explorado na região, chama a atenção para a criação de um plano de manejo que vise à redução de sua coleta.

Environmental influences on the composition and structure of the freshwater mussels in shallow lakes in the Cuiabá River floodplain / Influências ambientais na composição e estrutura de bivalves em lagoas da planície de inundação do rio Cuiabá

The maintenance of the freshwater mussels' community in lakes is determined by abiotic factors at the local scale and at regional scale by interspecific relations between the larvae of bivalves and fish host. Whereas the distribution pattern at local scale, our goal was to understand the abundance and community composition of bivalves and relate the environmental agents structuring this community. We sampled 20 lakes in the floodplain of the Cuiabá River using a standardized method of sampling. To evaluate the effect of environment on the community we applied multivariate inferential analyses. We found 1.143 individuals alive belonging into six species distributed at the family Hyriidae, Mycetopodidae, Sphaeridae and Corbiculidae. The results showed that in the Pantanal the bivalve assemblage structure is influenced locally by organic matter and particle size, variables that reflect the intense interactions between water-sediment. However it is important to emphasize that these environmental characteristics are the result of the dynamics of this system which is dependent on the flood pulse, a regional factor.

A manutenção da comunidade de bivalves límnicos em lagos é determinada por fatores abióticos em escala local e em escala regional pelas relações interespecíficas entre as larvas do bivalve e o peixe hospedeiro. Considerando o padrão de distiribuição em escala local, nosso objetivo foi conhecer a abundância e a composição da comunidade de bivalves e relacionar os agentes de estruturação desta comunidade. Foram amostrados 20 lagos na planície de inundação do rio Cuiabá usando método padronizado de amostragem. Para avaliar o efeito dos fatores abióticos sobre a comunidade aplicamos análises multivariadas inferenciais. Encontramos 1.143 indivíduos vivos, distribuidos em seis espécies pertencentes às famílias Hyriidae, Mycetopodidae, Sphaeridae e Corbiculidae. Os resultados demonstraram que no Pantanal, a estrutura da assembléia de bivalves é influenciada localmente pela matéria orgânica e granulometria, variáveis que refletem as intensas interações entre água-sedimento. No entanto é importante ressaltar que tais características ambientais são resultantes da dinâmica deste sistema o qual é dependente do pulso de inundação periódico, um fator de escala regional.

Invertebrados asociados al coral constructor de arrecifes Pocillopora damicornis en Playa Blanca, Bahía Culebra, Costa Rica / Invertebrates associated with the reef-building coral Pocillopora damicornis at Playa Blanca, Bahía Culebra, Costa Rica

Invertebrates associated with the reef-building coral Pocillopora damicornis at Playa Blanca, Bahía Culebra, Costa Rica. The coral reefs are one of the most diverse ecosystems in the planet, not only because their reef-building species but also because of the species that live above, on, inside and below them. Corals of the genus Pocillopora are recognized globally by harboring an important fauna of invertebrates among their branches, many of those considered obligate symbionts. The present investigation describes the fauna of invertebrates associated with the reef-building coral P. damicornis in Bahía Culebra, Costa Rica, their densities, frequencies, richness and diversities from 2003 to 2004. Five coral colonies were collected every 3-4 months at Playa Blanca within Bahía Culebra. A total of 448 individuals in 35 species were found: Harpiliopsis depressa, Trapezia ferruginea, Alpheus lottini, Fennera chacei, and Petrolisthes haigae, and the bivalve Lithophaga aristata, the predominant species. November was the month with the highest richness, diversity and taxonomic distinctiveness, while August had the lowest values. In general terms, the rainy season showed greater richness of species than the dry season. The species collected and their densities and abundances were similar to other sites along the Eastern Tropical Pacific. Bahía Culebra has been losing coral cover, which could have consequences on the diversity and abundances of associated corals organisms. These consequences include loss in the fertility of those organisms, a reduction in its function as cleaners and protection from coral predators, putting in risk their diversity, affecting the stocks of predatory fish that depends on them. Carrying out permanent monitoring of the associated cryptofauna of the coral Pocillopora is crucial to quantify losses or recoveries in the composition of associated invertebrates, and therefore in the functions that they perform in this ecosystem.

Los arrecifes coralinos son uno de los ecosistemas más diversos en el planeta, tanto por los organismos constructores como por aquellos que viven encima, sobre, dentro y debajo de ellos. Los corales del genero Pocillopora son reconocidos mundialmente por albergar una importante fauna de invertebrados entre sus ramas, los cuales son considerados como simbiontes obligatorios en una gran cantidad de casos. La presente investigación describe la fauna de invertebrados asociados al coral Pocillopora damicornis en Bahía Culebra, Costa Rica, describiendo sus densidades, frecuencias, riquezas y diversidades a través del tiempo. Para esto se colectaron 5 colonias cada 3-4 meses en Playa Blanca, Bahía Culebra. En total se encontraron 448 individuos en 35 especies, siendo Harpiliopsis depressa, Lithophaga aristata, Trapezia ferruginea, Alpheus lottini, Fennera chacei, y Petrolisthes haigae las especies predominantes. Noviembre fue el mes en el que se encontraron los mayores valores en los índices de riqueza, diversidad y diferenciación taxonómica, mientras que agosto fue el que presento los valores más bajos de todos. En términos generales, la época lluviosa mostro mayor riqueza de especies que la época seca. Así mismo, las especies colectados y los valores obtenidos son muy similares a otras zonas del Pacifico Oriental Tropical. Culebra ha venido sufriendo una perdida en la cobertura coralina, que podría tener consecuencias en la diversidad y abundancia de organismos asociados a corales. Estas consecuencias incluyen perdida en la fecundidad de estos organismos, una reducción en su función como limpiadores y protectores de depredadores del coral, poniendo en riesgo su diversidad, lo que puede afectar los stocks de peces depredadores que depende de ellos. Realizar monitoreos permanentes de la criptofauna asociada al coral Pocillopora va a ser determinante para cuantificar perdidas o recuperaciones en la composición de invertebrados asociados, y por ende en las funciones que estos desempeñan en este ecosistema.