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The functional diversity of echinoderms has been understudied, even though these organisms are critical components of various ecosystems, including coral reefs and hard-bottom benthic communities. Additionally, there are only a few papers relating the protection level of marine protected areas (MPAs) with functional diversity. In this study, we calculate the functional diversity of echinoids and asteroids in 11 coral and rocky reefs with different protection levels across the Mexican Pacific. We recorded the abundance of 15 echinoderm species comprising seven echinoid and eight asteroid species. More than 30 morphological and ecological traits of the censused species were evaluated to calculate two functional diversity indices: Rao’s quadratic entropy index (FDQ) and functional richness (FRic). Latitudinal patterns of functional diversity differed between groups. Asteroids showed the highest FDQ and FRic values in the Gulf of California. Echinoids showed FDQ peaks at the highest (Bahia de los Angeles; 28° 56′, − 113° 30′), and the lowest latitude (Bahias de Huatulco; 15° 43′, − 98° 08′) sites. The Ixtapa-Zihuatanejo site (17° 39′, − 101° 36′) had the highest FRic values. Generalized linear mixed models showed that protection level did not have any significant effect on FDQ or FRic. Latitude, on the other hand, did have a significant effect on asteroid functional diversity, although no significant effects were found for echinoids. The lack of an effect of protection level, and the support of a latitudinal gradient in terms of both taxonomic and functional diversity, has important implications for conservation efforts, supporting the idea of a protected area network to maintain adequate regional biodiversity.

The persistence of seaweeds as community-structuring organisms is critical for the maintenance of many ecosystem functions on rocky intertidal shores. We measured the relative importance of seaweeds in structuring the abundance, richness, and distribution of macroinvertebrates at three tidal levels on a rocky shore. Through manipulative experiments, we characterized temperature, irradiance, and desiccation underneath seaweed canopy plots made up of either Silvetia compressa or Stephanocystis dioica , assembled at three biomasses. We assessed differences in the abundance, richness, and the distribution of macroinvertebrates underneath the canopy as a function of seaweed species and biomass and evaluated differences due to the tidal height of the installed experimental seaweeds. We found that manipulated seaweed biomass significantly affected the community structure of associated macroinvertebrates at all tidal levels, especially at higher biomass treatments. Although contrary to other studies, we found no effect on richness underneath the canopies at any tidal height. Our results show that intertidal seaweeds provide protection from water loss, heat, and irradiance when compared to manipulative controls with no canopy cover. We also found that the relative importance of the experimental seaweed canopies in their ability to mitigate stressful abiotic conditions increased with prolonged emersion periods, such as at higher levels in the intertidal zone . At the higher tidal level tested, a greater abundance of macroinvertebrates was associated with the experimental canopies in comparison to the manipulation-control plots and the natural substrate. These results emphasize the role of intertidal seaweeds as bioengineers and highlight the importance of preserving and restoring high densities of leathery seaweeds on degraded shores in order to preserve the dynamics of the intertidal ecosystem overall.

Mexico harbors several types of coastal ecosystems both in the Atlantic (Gulf of Mexico and Caribbean) and in the Pacific (tropical and subtropical) on which the regional and national socio-economic development depends. They have been studied through several modeling approaches for management, conservation, and necessary ecological studies. In this chapter, we review and synthesize the most recent and relevant studies conducted, with particular emphasis on coral reefs. In the Caribbean, coral reefs are likely the most rapidly changing ecosystems with a net decline in the cover of reef-building corals accompanied by rapid increases of fleshy macroalgae over the last decades. Remaining coral communities are changing toward weedy coral species that are unlikely to support reef growth and thus provide important services to other species and humans. Since 2015 the Mexican Caribbean coast experienced a massive influx of drifting Sargassum spp. that accumulated on the shores, resulting in a build-up of decaying beach-cast material and near-shore murky brown waters (Sargassum-brown-tides), drastically modifying near-shore waters conditions by reducing light, oxygen (hypoxia or anoxia), and pH. The Gulf of Mexico’s coastal ecosystems have also been under significant threats because of human activities, such as gas and oil extraction, pollution, and fishing. Despite numerous studies conducted in the Pacific, biodiversity knowledge is still incomplete, highly biased toward specific habitats, and often narrow in taxonomic and spatial scope. Concurrently, ecological processes that drive biodiversity have been scarcely disentangled. In spite of sub-optimal conditions for coral calcification (lower alkalinity, upwelling, ENSO, high nutrients concentration) some coral reefs thrive in the Pacific. Calcification rate is disrupted with ENSO events (20–50% drop), but it is not correlated to historical changes in sea surface temperature and it might decrease between 15 and 22% due to ocean acidification.

The reef coral Pavona gigantea Verril, 1896 is an important reef builder in the eastern Pacific Ocean, and the present study sought to estimate its growth and mortality rates in Cabo Pulmo National Park, Mexico. The growth rate of 25 colonies was estimated with alizarin staining (mean growth rate was 10.1 mm yr–1, 95% CI 1.4) and the height of 87 colonies was measured to estimate the age structure of the population. The mean age was 14.85 (SE 1.91) yrs, with a minimum of 3 yrs and a maximum of 53 yrs. The mortality rate was fit by an exponential decay model and was estimated to be 0.0533 (SE 0.0171) yr–1. Based on these results, the presumed maximum longevity of a cohort is around 101 yrs. This is the first study to present the mortality rate and generation time for any species of the family Agariciidae, and might be useful for comparative studies or as a valuable baseline with which to compare current and future changes expected under climate change scenarios. Also, the estimation of natural mortality, potential growth, and the life span of this species may be useful to account for the potential success of restauration efforts.

In the southern Gulf of California, the Cabo Pulmo reef has been the focus of many studies because it is the northern-most coral reef in the eastern Pacific. It is a paragon of a well-managed marine protected area. Under the assumption that fishing mortality is negligible, we want to identify and quantify major energy flows in an ecosystem without human intervention and describe the ecosystem resources and their interactions among species, to provide a tool for ecosystem-based management. We built a trophodynamic model using Ecopath to perform network analysis. Based on fieldwork (October 2017 – May 2018) and literature review, we identified 57 functional groups comprising 51 consumers (including 15 top predators), five primary producers plus detritus, and cluster analysis of trait profiles. The connectance index (0.17) and the system omnivory index (0.22) are low, suggesting that consumers feed on a few discrete trophic levels. Biomass of primary producers (grazing food chain; 186.8 t km−2) provides 9,813 t km−2 y−1, whereas flow from detritus supply 344.9 t km−2 y−1. The transfer efficiency decreases as flows go up the food web, from 12% at TL II to 4% at TL X, and throughput cycled (including detritus) = 118.7 t km−2 y−1. In comparison with other coral reefs, we found that Cabo Pulmo complies with the attributes to resist disturbances, with an estimated total system throughput = 95,789 t km−2 y−1, a net system production = 38,535 t km−2 y−1, a large mean path length = 12.11, ascendency = 123,662 (52%) flowbits and overhead = 116,164 (48%) flowbits. The high quality of the ecosystem services provided by Cabo Pulmo and the scenic beauty appeals to developers. Although the system is resilient, unregulated human activities may impact the reef condition and decrease the residents' quality of life and that of all the people who make a living from the low impact activities currently in effect. The trophic web model presented here may help to improve the response capacity of the coalition of residents, authorities, diving companies, and NGO's to preserve the reef and be a key element to conserve the system by contributing to its best management.

Corals routinely lose tissue due to causes ranging from predation to disease. Tissue healing and regeneration are fundamental to the normal functioning of corals, yet we know little about this process. We described the microscopic morphology of wound repair in Pocillopora damicornis. Tissue was removed by airbrushing fragments from three healthy colonies, and these were monitored daily at the gross and microscopic level for 40days. Grossly, corals healed by Day 30, but repigmentation was not evident at the end of the study (40d). On histology, from Day 8 onwards, tissues at the lesion site were microscopically indistinguishable from adjacent normal tissues with evidence of zooxanthellae in gastrodermis. Inflammation was not evident. P. damicornis manifested a unique mode of regeneration involving projections of cell-covered mesoglea from the surface body wall that anastomosed to form gastrovascular canals.

Fourteen species of echinoderms and their relationships to the benthic structure of the coral reefs were assessed at 27 sites—with different levels of human disturbances—along the coast of the Mexican Central Pacific. Diadema mexicanum and Phataria unifascialis were the most abundant species. The spatial variation of the echinoderm assemblages showed that D. mexicanum, Eucidaris thouarsii, P. unifascialis, Centrostephanus coronatus, Toxopneustes roseus, Holothuria fuscocinerea, Cucumaria flamma, and Echinometra vanbrunti accounted for the dissimilarities among the sites. The spatial variation among the sites was mainly explained by the cover of the hard corals (Porites, Pocillopora, Pavona, Psammocora), different macroalgae species (turf, encrusting calcareous algae, articulated calcareous algae, fleshy macroalgae), sponges, bryozoans, rocky, coral rubble, sand, soft corals (hydrocorals and octocorals), Tubastrea coccinea coral, Balanus spp., and water depth. The coverage of Porites, Pavona, and Pocillopora corals, soft coral, rock, and Balanos shows a positive relationship with the sampling sites included within the natural protected area with low human disturbances. Contrary, fleshy macroalgae, sponges, and soft coral show a positive relationship with higher disturbance sites. The results presented here show the importance of protecting the structural heterogeneity of coral reef habitats because it is a significant factor for the distribution of echinoderm species and can contribute to the design of conservation programs for the coral reef ecosystem.

ResumenEl pepino café Isostichopus fuscus es una especie de alto valor comercial y en México está bajo protección federal. La pesquería se desarrolla en la península de Baja California, siguiendo reglas de manejo determinadas en Mesas Técnicas mediante acuerdos entre agencias de gobierno, científicos y pescadores organizados. Uno de ellos es que las evaluaciones de abundancia deben hacerse durante el día, cuando el pepino se oculta en oquedades, arrojando un valor inferior, pero no se ha comprobado. El objetivo del presente trabajo fue comparar la abundancia del pepino café en censos conducidos en transectos de 100×2 m, fijos al fondo y realizados durante el día y la noche del mismo día. Los resultados indican que hubo significativamente más pepinos observados en horas de oscuridad (promedio±error típico=3.714±0.075) que de luz (1.943±0.045), y que además es posible corregir la abundancia por transecto en el día con una ecuación lineal (pendiente=1.43; ordenada=1.18). La diferencia de cuota potencial calculada con los censos de día es aproximadamente un 15% menor a la que se obtendría en conteos nocturnos. Se concluye que la medida actual debe ser exitosa para un manejo precautorio del recurso.AbstractThe brown sea cucumber Isostichopus fuscus, is a holothurid with high commercial value. In Mexico it is federally protected, and the fishery in the Baja California Peninsula follows management actions established by technical committees, on the basis of agreements among government agencies, scientists and organized fishermen. One of these agreements is that evaluations of its abundance must be done during the day, as it has been suggested that during daylight hours the organisms hide inside holes, resulting on lower values, but this has not been demonstrated yet. Thus the objective of this study was to compare the abundance in census conducted inside fixed transects of 100 x 2 m, and surveyed at day and night of the same day. The results show that there were significantly more sea cucumbers seen during dark hours (mean±standard error 3.714±0.075) than during light time (1.943±0.045 per census); daylight estimated abundance can be corrected by a linear equation (slope=1.43; ordinate=1.18). Therefore, the quota estimated from censuses conducted during daylight is 15% lower than those that would be obtained at night. In conclusion, daylight censuses work as a precautionary management strategy of this species.

Evaluating the response of coral assemblages to different disturbances is important because variations in species composition may have consequences for ecosystem functioning due to their different functional roles in coral reefs. This study evaluates changes in diversity, structure and composition of coral assemblages of the coral reefs of two national parks in the northern sector of the Mesoamerican Barrier Reef System spanning the period from 2006 to 2012, just after the impact of two hurricanes in the area. Coral assemblages in the Cancún National Park included fewer species and lower live coral coverage ( < 15%) than those recorded in Cozumel. In the Cancún National Park, the species with the highest coral cover was Porites astreoides (more than 40% relative cover), and no significant temporal changes were observed in live coral cover and species composition. On the other hand, in the Cozumel National Park the dominant species were Agaricia agaricites, Siderastrea siderea and Porites astreoides, and the coral reefs showed an increase in live coral cover from 16% in 2006 to 29% in 2012. The dynamics of coral assemblages differed between the two parks: while there is an apparent stability in the current composition of the Cancún reefs, the Cozumel reefs show an increase in the abundance of the aforementioned dominant species. However, it is possible that the population characteristics of the species that dominate the coral assemblages in both national parks, such as those of fast population growth and of small colony size, do not entirely fulfill the main function of accretion and habitat heterogeneity, and more research is therefore needed to test this hypothesis. Evaluar la respuesta de las comunidades de coral a diferentes perturbaciones es importante ya que las variaciones en la composición de las especies pueden tener consecuencias en el funcionamiento del ecosistema, debido a los diferentes roles funcionales que cada especie tiene dentro de él. En este estudio se evaluaron los cambios en la diversidad, estructura y composición de las comunidades en los arrecifes de dos Parques Nacionales ubicados en el sector norte del Sistema Arrecifal Mesoamericano, durante el periodo 2006-2012, justo después del impacto de dos huracanes en la zona. En el Parque Nacional Cancún se registraron pocas especies de coral y una cobertura de coral vivo baja ( < 15%) sin cambios temporales significativos; la especie más dominante en este parque fue Porites astreoides con más del 40% de cobertura relativa. Por otro lado, los arrecifes de coral del Parque Nacional de Cozumel mostraron un incremento en la cobertura de coral del 16% en 2006 a 29% en 2012; las especies dominantes, y que incrementaron su cobertura en este periodo, fueron Agaricia agaricites, Siderastrea siderea y P. astreoides. Aunque la dinámica de las comunidades de coral fue diferente en ambos parques, es posible que las características poblacionales de las especies que dominan las comunidades de coral en todos los arrecifes no cumplan por completo con las funciones principales de acreción y heterogeneidad de hábitat; sin embargo se necesita más investigación para poder evaluar esta hipótesis.

"La almeja de sifon Panopea globosa es una especie de importancia comercial por su alta demanda en el mercado de Asia. El proposito de este estudio fue analizar el efecto de la concentracion de clorofila, temperatura superficial del mar, turbidez y ciclo de mareas en la estimacion de la densidad, distribucion espacial, y estructura poblacional de la almeja P. globosa en la region central del Golfo de California usando datos de satelite y observaciones de campo. Los organismos fueron recolectados mediante buceo semi-autonomo, entre noviembre 2009 y enero 2011. Se recolectaron un total de 10.114 almejas con un peso promedio de 997 ± 212 g (80%  800 g), y una longitud promedio de 132 ± 12,5 mm (80% de los organismos recolectados estuvieron por arriba de 130 mm, que es la talla minima legal de pesca). La densidad de P. globosa del area de estudio presento diferencias significativas entre las 3 agregaciones identificadas con alta densidad, pero la densidad no estuvo correlacionada con ninguno de los factores ambientales considerados."

Geoduck clams are a valuable natural resource along the northeast Pacific, which makes the assessment of the biological and genetic status of their populations a key element to provide a basis for their proper management and conservation. In the present study, we assess the genetic variability and connectivity of Panopea generosa Gould, 1850 among four localities in the northeast Pacific using mitochondrial (DNA sequences from COI and COIII) and nuclear (five microsatellite loci) data. We found no evidence of genetic differentiation among localities encompassing scales of 100s to 1000s of kilometers along the northeast Pacific, which is consistent with a large effective population size and extensive gene flow in the absence of significant barriers acting on the larval stages. Our genetic findings and phenotypic evidence are consistent with the existence of a single management unit shared by Canada, the United States and Mexico, but further studies with increased geographic and genetic sampling are warranted to better estimate the extent and direction of gene flow to help in international management and conservation measures of this valuable resource.

The sea cucumber Isostichopus fuscus (Ludwig, 1875) has been exploited, legally, and illegally, on the Baja California peninsula since 1988. The fishery was closed in 1994 due to overfishing symptoms but reopened in 2007 under management strategies and harvesting permits. Nocturnal samplings surveyed abundance, size and weight of I. fuscus. Density, proportion of individuals above the minimum size for fishing (MSF), weight–length relationship parameters, relative condition index (Kn), parameters of the von Bertalanffy growth equation (VBGE), individual and average age from the VBGE, natural mortality rate (M) and survival percentage cohort were estimated from the data set for the population in 2005–2007, and compared with the same population in 2013 at the Biosphere Reserve Bahia de los Angeles. Semi-structured interviews were also conducted to obtain the stakeholders' perspectives and opinions about the fishery. There were no significant differences in the weight–length relationship (W = 7.17·L1.29), relative condition index (Kn = 1.08), and parameters of the von Bertalanffy growth equation (L∞ = 35.74 cm, K = 0.26 y−1), between the study periods. The population in the 2005–2007 period was mainly constituted by individuals

There is a growing demand for “end-to-end” models, which are modeling tools used to analyze and understand the fundamental complexities of marine ecosystems and processes emerging from the interaction of individuals from different trophic groups with respect to the physical environment and, even, human activity. These models are valuable quantitative tools for ecosystem-based management. To explore potential answers to complex questions regarding ecosystems using these models, it is necessary to incorporate classical ontogenic changes through the life cycle of target individuals, in addition to inherited behavioral strategies, as an additional differentiating aspect, particularly when the behavior has a direct impact on the ecosystem phenomena under study. However, it is difficult to combine different fine scale time and spatial granularities to infer animal behavior and ontogenic development. This complexity has kept these two levels of analysis separated, because most current tools do not have the required computational resources and advanced software architecture. To address this issue, we propose an individual-based modeling framework that is capable of handling and unifying the two experimental categories with a comprehensive biological and behavioral model that strictly adheres to the physiological functions of ingestion, growth, and metabolism of organisms. In addition, this model incorporates the exchange and transfer of mass and energy through local interactions at all trophic levels (lower to higher), the physical environment, and anthropogenic activity. For the framework to model short time events, such as classical predator–prey interactions, while also generating long-term ecosystem emergent properties, a special interleaving scheduling engine and physical space computer model was devised, which optimizes memory and processing resources. The framework was tested through several experiments with a three-population ecosystem containing up to 40 thousand organisms evolving inside a 200,000 m2 simulation environment during 12,000 model-hours; yet, requiring only a few hours of program execution on a regular personal computer. The model included various environmental physical elements, such as several hundred shelters, the number of which can be easily modified in each experiment to simulate substrate degradation and its impact on populations. With the aid of the quantitative and qualitative tools provided by the model, it was possible to observe a coupling between prey and predator population dynamics. In conclusion, we confirmed that the end-to-end model developed here could successfully generate detailed specific hypotheses about fish behavior and quantify impacts on population dynamics.

Coral reefs are considered to be valuable ecosystems due to the goods and services that they provide. However, these ecosystem services are highly dependent on the physical structure of the reef, which in turn depends on the species composition of hermatypic corals. In this study, we explored the functional potential of reefs with a new index that takes into account coral cover, the calcification rate, rugosity, and the height of each species. In June 2019, we surveyed 11 reefs from the southern Mexican Pacific (15°40′N, 96°29′W−15°45′N, 96°5′W) to estimate coral cover and collect quantitative morphometric data of ~15 haphazardly selected coral colonies per site (N = 102). We estimated the calcification rates and structural complexity of the species present and then calculated the Reef Functional Index (RFI), which estimates the species-specific functional contribution of the corals in reef systems by integrating their capacity to create complex three-dimensional structures through calcium carbonate precipitation with morphological complexity. We modelled the effects of shifting species compositions through a permutation approach with 6435 possible combinations. We found a mean coral cover of 48.5 ± 18.09% (±SD) dominated by Pocillopora damicornis, Pocillopora verrucosa, and Pocillopora capitata and low abundance of Porites panamensis and Pavona gigantea. The mean RFI was 0.71 ± 0.1. The permutation model showed that the RFI was very close to its maximum potential (96%) when the relative abundance of pocilloporids was ≥60% and decreased as the relative abundance of massive corals increased. At maximum evenness, the RFI value was at 92% of its maximum potential. Our data highlight the importance of pocilloporids to the functioning of reefs in the Eastern Tropical Pacific (ETP) and confirm that P. damicornis is the primary reef builder in the region. Nevertheless, our findings also highlight the vulnerability of these reefs given that branching corals are more susceptible to environmental disturbance than slow-growing massive corals. In a rapidly changing environment, the future of ETP reefs depends not only on the survival of pocilloporids but also on the ability of coral reefs to withstand highly variable oceanographic conditions as complete ecosystems.

The rearrangement of coral assemblages may produce significant changes in coral community calcification, yet it is not understood how the modification of community structure in depauperate areas under climate change scenarios may affect reef functionality. Observed coral community calcification (OCC) was calculated using coral cover data from 126 sites across the eastern tropical Pacific (ETP). To assess the effect that species assemblages exert on potential coral community calcification (PCC) of ETP reefs, we implemented a novel permutation approach for this purpose. We contrasted OCC across the ETP against the PCC of hypothetical monospecific and maximum ecological evenness (ME) ETP reefs and monogeneric Indo-Pacific (IP) and Caribbean (C) reefs. Average coral cover (21 ± 23%; mean ± SD) and OCC (8.23 ± 11.32 kg m−2 yr−1; mean ± SD) in the ETP were not related to species richness but to Pocillopora abundance and calcification. For any level of coral abundance or species richness, the permutation model indicates that PCC depends on community structure: the PCC of Pocillopora monospecific reefs reaches its maximum; PCC drops to half of its potential when ME is attained; and PCC reaches its minimum when slow-growing species turn dominant. A dynamic model with changing community structure based on the differential species tolerance to climate change showed a similar pattern as the permutation model. ETP Pocillopora reefs have lower PCC than IP Acropora, IP Pocillopora and C Acropora. Massive taxa are more tolerant to climate change and could replace branching taxa if environmental pressure trends in the ETP continue, meaning an ∼85% drop in PCC.

The brown sea cucumber Isostichopus fuscus is the most important commercial holothurian in the eastern Pacific, and its high market value caused overfishing and sharp declines of its populations and catches in several Latin American countries. In Mexico, the fishery has been intense in the northern Gulf of California since the 1990s, and it is currently under strong regulation. To evaluate the current status of the organisms, we measured the size, weight and estimated the relative condition index (Kn) of 702 specimens sampled in 86 rocky reefs of that region in 2016, at depths from 3 to 22 m. Mean length ± SD was 22.32 ± 5.23 cm, lower than average in the northern Gulf, but nevertheless, the average weight was 420.61 ± 192.48 g, among the highest recorded in the eastern Pacific; this is presumably due to the high primary production of the region that favors the presence of well-nourished organisms. The weight (W)-length (L) relationship was W = 3.27 L1.56, and condition index ranged from 0.045 to 2.13 (mean Kn = 0.96 ± 0.29), a figure that did not differ to that reported along the Mexican Pacific. There were differences in the value of Kn among sites, being higher in areas that are subject to the low fishing effort. Normal 0 false false false ES-MX X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:ES-MX;}

Gobies are the most diverse marine fish family. Here, we analysed the gamma-diversity (γ-diversity) partitioning of gobiid fishes to evaluate the additive and multiplicative components of α and β-diversity, species replacement and species loss and gain, at four spatial scales: sample units, ecoregions, provinces and realms. The richness of gobies from the realm Eastern Tropical Pacific (ETP) is represented by 87 species. Along latitudinal and longitudinal gradients, we found that the γ-diversity is explained by the β-diversity at both spatial scales, ecoregions and provinces. At the ecoregion scale, species are diverse in the north (Cortezian ecoregion) and south (Panama Bight ecoregion) and between insular and coastal ecoregions. At the province scale, we found that the species turnover between the warm temperate Northeast Pacific (WTNP), Tropical East Pacific (TEaP) and the Galapagos Islands (Gala) was high, and the species nestedness was low. At the ecoregion scale, historical factors, and phylogenetic factors have influenced the hotspots of gobiid fish biodiversity, particularly in the Cortezian, Panama Bight and Cocos Island ecoregions, where species turnover is high across both latitudinal and longitudinal gradients. At the provincial level, we found that the contributions of the β-diversity from north to south, in the WTNP, TEaP and Gala were high, as result of the high number of unique species. Species turnover was also high at this scale, with a low contribution from species nestedness that was probably due to the low species/gene flow within the provinces. These results highlight the importance and successful inclusion of a cryptobenthic fish component in ecological and biogeographical studies.

Cliona vermifera is one of the most abundant excavating sponges in Mexican coral reefs, and represents a potential threat to their health. It appears to have limited dispersal potential, but, paradoxically, it is widespread over much of the 2000 km of Mexican Pacific waters, suggesting mechanisms of long-distance dissemination. Despite its ecological importance, nothing is known about its patterns of genetic structure and connectivity in space and time. In this study, we assess levels of genetic structure and test the hypothesis of limited dispersal and isolation by distance among coral reef systems in the Mexican Pacific. Genetic diversity levels were consistently low in DNA sequences from two mitochondrial genes and one nuclear gene; however, they revealed strong and significant genetic differentiation throughout the study region. Patterns of genetic differentiation from the slow-evolving mitochondrial, but not the nuclear, genes were geographic scale dependent. We found higher mitochondrial genetic similarity among localities at 10–100s km than at larger scales (100–1000s km). However, all samples were genetically differentiated at the nuclear locus, which is inconsistent with frequent long-distance dispersal. Significant isolation by distance is consistent with life history traits shared by boring sponges: a short larval period and larval philopatric behavior. The patterns of genetic differentiation in C. vermifera concur with those found in other sympatric coral species, and suggest the influence of community-wide ecological and genetic mechanisms on the genetic makeup of coral reef species in the Mexican Pacific. Fixed genetic differences suggest that the southern population of Oaxaca may be experiencing incipient speciation.

Coral reefs are in crisis worldwide. Fish play a key role in the resilience of reefs because most of the biomass of the ecosystem flows through them. Evidence indicates that the response to stressors will vary markedly depending on the resilience of the ecosystem. In order to assess the functional groups of reef fishes, morphometric and ecomorphological analyses were carried out on the shape and diet of 117 reef fish species from the Mexican Eastern Pacific (MEP) from 23°N to 15°N, spanning the years 2009–2012. Six trophic groups were identified and subdivided into 19 functional groups: (A) detritus and plants consumers, three morphologies; (B) plants and zoobenthos consumers, four morphologies; (C) zoobenthos consumers, two morphologies; (D) zoobenthos and zooplankton consumers, three morphologies; (E) zooplankton and nekton consumers, three morphologies; and (F) nekton consumers, four morphologies. Our main conclusions are: (i) fish communities of the MEP have a high degree of ecological redundancy; (ii) fish diversity is not related to the coral cover; and (iii) the combination of using both morphology and diet produce a more effective classification of functional groups. Future studies such as these will allow a deeper understanding of environment and it will help illuminate the effects of fish morphology and diet on population structure.

In the upper Gulf of California, a lucrative fishery of the Cortes geoduck Panopea globosa (Dall 1898) is developing rapidly. Both exploited and unexploited areas for this fishery still exist in this area. The effect of the data source of the length-atage data on growth models fitted to Panopea globosa was evaluated. Five growth models were tested: von Bertalanffy, logistic, Gompertz, Schnute, and Schnute-Richards. The parameters of each model and their confidence intervals (CIs) were computed using the maximum likelihood method. Multimodel inference was used to average the asymptotic length for each area. The bestfitting model was selected using Akaike's information criterion (AIC). According to this criterion, the logistic growth model best described the growth of P. globosa in unexploited beds, and the Schnute models performed best in exploited beds. The asymptotic length values obtained frommultimodel inferencewere 161.88 mm (95% CI, 161.83–161.93 mm) in unexploited beds and 205.20 mm (95% CI...

Geoduck (Panopea globosa and Panopea generosa) fisheries regulations in the Gulf of California and Baja California Peninsula, Mexico, are based on a minimum legal size (shell length, 130 mm), limited bed harvests with densities greater than 0.4 geoduck/m2, maximum allowable catch, and restrictions on fishing activity on identified beds. Data on age structure and growth rate for geoducks could greatly improve fisheries management in the region; however, variability in size-at-age data for geoducks has made it difficult to develop a sound management strategy, and the presence of outliers in the data have influenced parameter estimates significantly. Different probability density functions can be applied as fat-tail distributions in mixture probability distributions. In the current study, outlier effects on candidate growth models in P. globosa were analyzed, as well as model performance when parameters were estimated using a two-component mixture probability distribution function. The best candidat...

To investigate sex-related differences in the skeleton of the reef-building coral Montastraea cavernosa, a gonochoric broadcaster species with an annual cycle of gametogenesis, we collected six colonies during the reproductive season. Sex was determined by histological techniques and sclerochronological characteristics of digital X-ray images. Our results show, as previously reported for other gonochoric corals, differences in the sclerochronological characteristics between female and male colonies. Tissue thickness, density and calcification rate are significantly lower in females than in males, whereas there is no difference in extension rate between sexes. These are the first complete sclerochronological results reported for M. cavernosa, and for gonochoric species with solid skeletons. We conclude that sex differences in this coral arise by coupling energetic costs of reproduction and the growth strategy, and argue that it is important to consider how sclerochronological characteristics vary between sexes of gonochoric species when interpreting climate and environmental proxies from coral skeletons.

The brown sea cucumber Isostichopus fuscus is highly prized and intensively fished, yet no studies of its reproductive cycle at its northernmost distribution site exist. To characterize its reproductive cycle, monthly surveys (Oct 2014-Dec 2016) that included gonad collection were conducted in 118 sites along the eastern coast of Baja California, including islands from Bahía San Luis Gonzaga (29o 49’ 14.18” N, 114 o 3’56.17” W) to the 28th parallel north. A total of 2 808 sea cucumber specimens were measured (mean length ± SD = 21.4 ± 6 cm) and weighed (375.6 ± 249 g). Seven hundred and seventeen organisms were dissected but only 553 gonads were suitable for processing through histological analysis to identify sex and developmental stage. Of these individuals, 224 were female, 162 were male, 157 were undifferentiated and 10 were hermaphrodites, resulting in a sex ratio that was significantly different from 1:1 (χ2 = 36.63, P = 0.03, df = 23). There was no statistical difference (p > 0.05) of either size or weight between males and females, but females were larger than males. The length-weight relationship observed was W = 0.18L2.4, r2 = 0.82, p

Calderon-Aguilera points at the environmental implications of the fisheries sector’s performance in North America, discussing the current context and the way forward. He examines current perspectives on transboundary fisheries and market rules, focusing on geoduck fishery from Canada to Mexico. He also considers environmental aspects with long-term variations like the Pacific Decadal Oscillation, midterm variations like El Nino Southern Oscillation (ENSO), as well as seasonal variations. This chapter also explores climate change effects on fisheries, collaborative research between the three countries, and includes an assessment about whether the dolphin–tuna fishery and the US embargo to Mexico has been related to environmental concerns or commercial interests.

Porites panamensis is a hermatypic coral present in the eastern Pacific Ocean. Skeletal growth parameters have been reported, but studies of the relationship between annual calcification rates and environmental controls are scarce. In this study, we investigated three aspects of the annual calcification rates of P. panamensis: growth parameters among three P. panamensis populations; the sea surface temperature as a calcification rate control spanning a latitudinal gradient; and calcium carbonate production among three sites. Growth parameters varied among the sites due to the colony growth form. Massive colonies in the north showed a higher calcification rate than encrusting colonies in the south (mean: 1.22–0.49 g CaCO3 · cm−2 · yr−1), where variations in calcification rates were related to growth rate (0.91–0.38 cm · yr−1) rather than to skeletal density differences (overall mean ± SD, 1.31 ± 0.04 g CaCO3 · cm−3). Our results showed a positive linear relationship between annual calcification rates and sea surface temperatures within these P. panamensis populations. Differences were related to distinct oceanographic environments (within and at the entrance of the Gulf of California) with different sea surface temperature regimes and other chemical properties. Different populations calcified under different environmental conditions. Calcium carbonate production was dependent upon the calcification rate and coral cover and so carbonate production was higher in the north (coral cover 12%) than in the south (coral cover 3.5). Thus, the studied sites showed low calcium carbonate production (0.25–0.43 kg CaCO3 · m−2 · yr−1). Our results showed reduced calcification rates, regional temperature regime control over calcification rates, different growth forms, low coral cover and low calcium carbonate production rates in P. panamensis.

There is an increasing demand for fisheries resources worldwide. For example, the Asian markets have traditionally consumed sea cucumber as a delicacy and their buoyant economies have promoted demand for it in recent years. The brown sea cucumber Isostichopus fuscus is the most valuable species from the Eastern Pacific and it has been almost depleted due to overfishing. In this work, we analyzed data of sea cucumber abundance collected monthly (October 2014–December 2016) along the west coast of the Gulf of California (29.95 oN – 28.05 oN) in 1,107 swath (25 × 2 m) quadrats performed at 118 sites with the goal of determining if current fishing quotas are sustainable. We applied a Bayesian hierarchical modelling approach with integrated nested Laplace approximation (INLA) to this data to account for spatial structure in the data when calculating densities. The observed density ranged from a minimum of 0 to a maximum of 0.58 ind/m2, with an average of 0.03 ind/m2 in suitable habitat, defined as the habitat less than 30 m deep and with hard substrate. There are large spatial variations in abundance, but the overall mean suitable habitat is 15.7% (min = 7.8%, max = 28.8%) of the total fishing area. Current quotas are usually higher than 5% of the lower bounds of population density estimates. We propose, among other management measures, that quotas should be granted taking into account the spatial structure of sea cucumber densities as well as the proportion of suitable area within each estate. Given the high levels of illegal fishing within the Gulf of California, it is imperative that quotas are based on the lower bounds of spatially explicit density estimates – along with increased surveillance and enforcement – if the long-term commercial sustainability of the fishery is to be maintained.

The reproductive cycle of Panopea generosa at the southernmost limit of its distribution in the State of Baja California, Mexico was studied, using standard histological techniques, oocyte cohort analysis and a gonadosomatic index. The reproductive cycle of P. generosa begins in late autumn, with a developing phase in winter and continuous proliferation and spawning from April throughout October. During this period, several oocyte cohorts were developed, but only three attained maturity, the rest being reabsorbed into the gonad. Gamete reabsorption within the gonad might reflect a conservative pattern of nutrient recycling. Ripe gametes were continuously released with a main spawning at the beginning of summer, when temperature was increasing. Spawning of less intensity during late summer occurred when the temperature reached its seasonal peak. The gonadosomatic index correlated well with development of the species' reproductive season. The sex ratio was dominated by females (2.8:1) although sexua...

El conocimiento ecologico de corales arrecifales en el Pacifico mexicano es escaso, por lo que el objetivo de este trabajo fue determinar la estructura de la comunidad de corales hermatipicos en el arrecife de Carrizales, Colima, mediante el uso de transectos y buceo autonomo (junio y octubre 2005, septiembre 2006). De las 13 especies de corales encontradas, Pocillopora verrucosa fue la mas abundante y siete representan nuevos registros, sobresaliendo Psammocora contigua, primer registro para el Pacifico Oriental. No hubo diferencias significativas de abundancia entre profundidades, pero la zona somera presenta una mayor cobertura. Este sitio presenta una de las riquezas y cobertura de coral mas alta (61%) en el Pacifico Mexicano y valores de diversidad (H´=0.44±0.02), uniformidad (J´=0.76±0.02), y de diferenciacion taxonomica (Δ*=45.87±3.16) relativamente altos. Actualmente la region no presenta grandes perturbaciones pero el creciente desarrollo economico de Manzanillo, uno de los principales puertos comerciales del pais, ademas del creciente numero de turistas, podrian afectar al arrecife, por lo que se sugiere implementar medidas de proteccion con el fin de mantener al arrecife mas importante del litoral de Colima.

Density banding provides a record of per- formance of coral colonies over time and across envi- ronments, and offers 3 measurable variables: skeletal density, extension rate, and calcification rate. Skeleton formation is energetically expensive for corals and may be associated with other energy-dependent processes, such as reproduction. Egg production requires more energy expenditure than sperm production. Thus, cal- cification rate is hypothesized to be different for each gender. To evaluate differences in skeletal growth be- tween males and females, we studied a gonochoric massive coral, Porites panamensis, from 3 regions of the Gulf of California. Colony sex was identified using histology methods, and growth parameters were meas- ured using photo-densitometry of X-radiographs. Ex- tension and calcification rates were significantly higher in male colonies than in females (by 18 to 23%) at 2 of our 3 study sites, while skeletal density was similar in both genders. Our results support the hypothesis of a gender bias in growth characteristics and suggest that environmental conditions may impact coral calcifica- tion differently in male and female colonies.

Ocean acidification is widely accepted as a primary threat to coral reef populations. Negative physiological effects include decreased calcification rates, heightened metabolic energy expenditure, and increased dissolution of coral skeletons. However, studies on the dissolution of coral skeletons structures under ocean acidification conditions and their implications on sediments remain scarce. In this work, we examined skeletal dissolution kinetics from four of the most representative hermatypic corals of the Eastern Pacific coasts (Pocillopora, Porites, Pavona, and Psammocora). Samples were treated with a highly acidic solution for defined periods of time, and measurements of dissolved calcium ([Ca+2]) were used to evaluate the kinetics of coral skeleton dissolution. All genera tests except Porites showed a zero reaction rate. Porites exhibited a first-order reaction and a faster reaction rate than other genera. Compression strength tests and skeletal density did not correlate with reaction rate. Pavona showed greater structural strength. Porites were the most susceptible to acidic dissolution compared to other genera tested due to their morphology, i.e., possession of the largest surface area, suggesting a high vulnerability under low-pH conditions. The hierarchical response in dissolution kinetics among coral genera tested suggests that the most soluble coral might act as a buffer under ocean acidification conditions.

The Cortes geoduck (Panopea globosa) has been considered a Gulf of California (GC) endemic but anecdotal and unpublished evidence has suggested its presence in Bahía Magdalena (BM), on the Pacific coast of southern Baja California. Establishing the identity of geoduck clams and their distribution limits is not only of clear biological significance to understand their structural and functional variation, but is also of consequence for their conservation and management, given the multi-million dollar fishery they support in north-west Mexico. We analysedPanopeaclams from Mexican populations, including BM, using an integrative approach including genetics, morphometrics, and an ecological niche model. Our genetic results (restriction fragment length polymorphisms of nuclear ribosomal DNA and mtDNA cytochrome c oxidase subunit I sequences) clearly identify BM geoducks asP. globosa, implying a significant geographical range expansion outside of the GC and refuting its status as endemic to the Gulf. On the other hand, clams from BM were phenotypically different (shell significantly higher) from other MexicanP. globosaandPanopea generosaspecimens, which may account for the confusion in their morphological identification. The ecological niche model forP. globosa, integrating ecological and distributional data from the GC, revealed a very low probability (

Summary In spite of their ecological and economic importance, reef fishes from the coast of Oaxaca, Mexico are rarely studied, therefore precluding their management and conservation. In order to identify the set of habitat characteristics/environmental conditions that predict major shifts in fish assemblages in space and time, a stationary census (5′, φ = 5 m) was conducted on a semi-monthly basis from 2006 to 2009 at patch reefs along the coast. Habitat configuration was gathered using 25 m long point-intersect transects (data every 25 cm), recording all underlying coral species and substrate characteristics (rocks, sand, algal mats, rubble or dead corals). Recorded were 65 452 fishes grouped in 11 orders, 36 families, 65 genera and 89 species. Labridae (nine species), Pomacentridae (eight species) and Serranidae (seven species) were the most frequent families. Abundance is severely skewed among species; four species Thalassoma lucasanum, Chromis atrilobata, Apogon pacificus and Stegastes acapulcoensis comprise nearly 59% of the fish abundance, 11 species contribute 30%, whereas most of the species (75) can be considered as rare since they contribute

There are 2 species of geoduck fished commercially in northwest Mexico: Panopea generosa, along the Pacific coast of the Baja California peninsula, and Panopea Globosa, in the Gulf of California and in Bahia Magdalena. This study describes the status of the geoduck clam fishery in northwestern Mexico. Recent surveys suggest an ample distribution of beds along both coasts of Baja California and the coast of Sonora. Landings have increased from 49 mt in 2002 to 2,000 mt in 2011. The fishery has a current annual value of approximately US$30 million, and in Sonora, stock assessments estimate the potential yield to be around 1,800 mt. Fishers in Sonora have expressed an increasing interest to enter into the geoduck fishery, and a total of 1,173,898 pieces have been authorized for new extraction in 2012. We have conducted surveys in 24 beds from February 2009 to October 2011 to evaluate the resource. Given the long life cycles of geoduck, low recruitment and high fishing rates threaten the viability of...

Corals in the Eastern Pacific extend south from the Gulf of California to Ecuador and oceanic Chile, and west from Colombia to Clipperton Atoll. Nevertheless, large stretches of the Mexican Pacific remain fundamentally unstudied. Therefore, to assess the current conditions of coral communities, a coastal fringe ∼300 km long (17°40′ N, 101°39′ W to 16°46′ N, 99°49′ W) was surveyed within the Southern Mexican Pacific, between 2005 and 2009. Fifteen stony coral species were identified at 13 coral communities and six Pocillopora-dominated fringing reefs, with Pocillopora verrucosa and Pocillopora damicornis the primary contributing taxa. Reef development was identified in embayments or behind rocks or islands that offered shelter from northern and northwestern winds. Observations of Pocillopora effusus, Pocillopora inflata, Porites lobata, Pavona clavus, and Pavona varians expanded the species known geographic ranges by several degrees of latitude, suggesting reef building fauna comprised a mixture of widespread and relatively rare Eastern Pacific corals. Results indicated greater live coral cover in the Ixtapa-Zihuatanejo area (15–73%) than in the Acapulco localities, which had high algal dominance; the reefs in the latter region exhibited high erosion. Regional differences are likely the result of long-standing anthropogenic pressures around Acapulco since 1950, when it became an important tourist destination. This paper is the first detailed report of ecologically stressed corals and coral reefs from the state of Guerrero on the Mexican Southern Pacific coast.

Mexico harbors more than 10% of the planet's endemic species. However, the integrity and biodiversity of many ecosystems is experiencing rapid transformation under the influence of a wide array of human and natural disturbances. In order to disentangle the effects of human and natural disturbance regimes at different spatial and temporal scales, we selected six terrestrial (temperate montane forests, montane cloud forests, tropical rain forests, tropical semi-deciduous forests, tropical dry forests, and deserts) and four aquatic (coral reefs, mangrove forests, kelp forests and saline lakes) ecosystems. We used semi- quantitative statistical methods to assess (1) the most important agents of disturbance

Coastal ecosystems are influenced by a suite of drivers and interactions, resulting in complex dynamics not captured by single species, single driver approaches. Kelp forest ecosystems of the California Current region are subject to extreme environmental variability as well as a suite of fishing pressures which remove organisms throughout the food web. Here, we present a food-web model to assess ecosystem-wide effects of different fishing strategies which can also be used to estimate the effect of warming, acidification and hypoxia on the structure and function of a highly productive temperate ecosystems. We built a mass-balanced model of a kelp forest ecosystem near the southern limit of distribution in the northern hemisphere (Isla Natividad, Mexico). The model is informed by extensive ecological monitoring of fish, benthic invertebrates, and macroalgae conducted annually from 2006 to 2016 at 5 sites around the island. The model includes 40 functional groups (FG) defined on the basis of commercial interest, ecosystem function and feeding guild, including birds, marine mammals, fish (13 FG), commercial species (7 FG), macroinvertebrates (8 FG), zooplankton, the giant kelp Macrocystis pyrifera, six macroalgae, phytoplankton and detritus. The estimated throughput was 5477.6 t·km−2·year−1 (26% consumption, 27% exports, 24% respiration and 23.7% detritus). The sum of all production was 2727.9 t·km2·year−1, and the total primary production/total respiration ratio was 2.4. This model, based on a detailed, multi-year monitoring program in the kelp forests, provides a valuable tool for exploring drivers of change in these vulnerable marine ecosystems and fisheries.

Geoduck clams have become the most profitable emerging fishery resource in Northwest Mexico, with profits of more than US$30 million during the last few years. The fishery targets two species—Panopea globosa in the Gulf of California and Panopea generosa on the Pacific coast of Baja California—but is managed indistinctively. Despite its growing importance, scientific research on the basic biology of the Mexican stocks has been inexistent until recently. A major gap in knowledge is the interspecific distinction in structural and functional biological attributes. Consequently, the aim of this article is to provide the biological basis of phenotypic (morphometric) and genetic distinction between P. globosa and P. generosa to assist in their management and conservation. We found that P. generosa from the Pacific coast of Baja California is significantly smaller than P. globosa from the northern Gulf of California in shell length, width, and height (t-tests, P < 0.0001), and that shell width and height scale differently to length in both species. Multivariate analyses (multidimensional scaling) provided additional support (stress ¼ 0.04) to the species and geographical distinction. Genetic data from the nuclear ribosomal DNA provided contrasting results between polymerase chain reaction- restriction fragment length polymorphisms and direct sequencing. Ribosomal DNA sequences revealed higher diversity (haplotype and nucleotide) in P. globosa. Standing in sharp contrast with the low intraspecific divergence, was the very large genetic differentiation between species in excess of 20% corrected Kimura 2-parameter sequence divergence and accounting for 98% of the molecular variance of both species. This differentiation was found to be of consequence for novel methods of molecular species identification and for the interpretation of the phylogeography and evolution of Panopea in the North Pacific. The relevance of our findings goes to the heart of filling a major information gap pertaining to the distinction of both species. Scientific and lay stakeholders of these valuable resources need to ascertain and acknowledge this distinction to adopt sustainable management and exploitation practices.

A commercial fishery for gcoduck Panopea generosa in Baja California began in 2002 and has since achieved landings comparable with those in Washington state and British Columbia, Canada, where geoduck fisheries developed in 1970 and 1976, respectively. This investigation was motivated to acquire the knowledge of population biology of P. generosa at the southernmost extent of its distribution that is required to establish a biological basis for fishery management decisions. This article was further motivated to assess the appropriateness of the current minimum legal size of 130 mm established by the Mexican fishing authorities. Morphometric relationships, age, and growth, and natural mortality of P. generosa were investigated with animals collected from Bahia de San Quintin and Islas Coronado, Baja California, Mexico, collected monthly from April 2008 through January 2009. Ages were obtained by counting growth bands in cross-sections of the shell hinge plate and utilizing cross-dating methods to i...

This article describes the timing of gametogenic development and spawning in a population of geoduck clams, Panopea globosa (Dall 1898), from the Upper Gulf of California and its relationship to temperature changes and primary productivity. Clams were collected monthly over 1 year (March 2008 to March 2009), and salinity, dissolved oxygen, and substrate type were recorded during each survey. Standard histological analyses and measurements of oocyte diameters were used to describe the timing of gametogenic development and spawning. Satellite data for temperature and chlorophyll were gathered to test a general conceptual planktonic larval development model. The results demonstrated that reproductive activity was triggered by a steep decrease in temperature 4 months prior to the peak of productivity. Thus, larval development matches favorable conditions, as predicted by Cushing's Match—Mismatch Hypothesis.

El calentamiento global y la acidificacion del oceano influyen en la calcificacion de los corales. No obstante, existe poca informacion respecto a los parametros de crecimiento de las principales especies de corales constructores de arrecifes en areas de crecimiento marginales como la costa del Pacifico del sur de Mexico. Se obtuvieron los parametros de crecimiento de 8 especies de corales hermatipicos (especies con crec imiento masivo: Porites panamensis, Porites lobata, Pavona gigantea y Pavona varians ; especies con crecimiento ramificado: Pocillopora meandrina, Pocillopora damicornis , Pocillopora verrucosa y Pocillopora capitata ) en 2 zonas de la costa del Pacifico del sur de Mexico. Los corales ra mificados tuvieron ta sas de calcificacion ma s altas (2.99–5.23 g CaCO 3 cm –2 ano –1 ) que los corales masivos (0.34–1.13 g CaCO 3 cm –2 ano –1 ). Se observo una relacion significativa entre la temperatura superfi cial del mar (TSM) y la densidad del esqueleto para todas las especies de coral masivo. Ademas, 2 especies de coral masivo ( P. gigantea y P. varians ) mostraron una relacion significativa entre la tasa de calcificacion y la TSM. Las surg encias en la region del golfo de Tehuantepec acarrean aguas con bajo pH y baja saturacion de aragonita, y podrian estar afec tando negativamente la tasa de calcificacion de los corales en el area de estudio

El Golfo de California es una zona de importancia por su alta biodiversidad y por ser clave para las pesquerías artesanales en México. Existe preocupación de las amenazas que existen sobre él, como el calentamiento global, que ha causado cambios en las comunidades. Por esto, se pretendió estimar el posible impacto del incremento de la temperatura oceánica sobre especies claves. Se estimaron los efectos potenciales del incremento de la temperatura sobre especies arrecifales. Para realizar esta estimación, se obtuvo información de la temperatura superficial oceánica (NOAA), se construyó un modelo de tendencias de cambio de temperatura. Los datos biológicos se obtuvieron de censos visuales de seis regiones del Golfo entre el 2005 y el 2007. Posteriormente se realizó un modelo lineal por pasos (stepwise), con él se proyectaron cambios en las abundancias y distribución de los organismos. Se estima que para el año 2050 la temperatura promedio se eleve 0.63°C; además, especies de importancia económica reducirán notablemente su abundancia al sur de los 25° N. Por último, modelamos la respuesta de 20 especies de peces más abundantes del Golfo para estimar cambios a escala comunitaria. La simulación indica desequilibrios en la función y estructura de las comunidades. El calentamiento oceánico provocará un desbalance en la composición y función ecológica de los ecosistemas por medio de alteraciones graduales en las abundancias de las especies. Por eso, la puesta en práctica de programas de monitoreo de las comunidades sería una herramienta fundamental para detectar efectos futuros del calentamiento. The Gulf of California is important because of its high biodiversity and because it is a key area for artisanal fisheries in Mexico. There are current concerns regarding threats to the Gulf, such as global warming, that have caused major changes in marine communities. Consequently, the aim of this study was to estimate the possible impact of increasing ocean temperature on key species. Potential effects of such increase on reef species are thus estimated in this paper. In order to prepare this estimate, sea surface temperature (SST) was obtained from the NOAA database, and a temperature change trend model was constructed. Biological data was obtained from visual censuses of six regions within the Gulf between 2005 and 2007. A stepwise linear model was used to forecast potential changes in species abundance and distribution. It is estimated that by 2050 average temperature will increase 0.63°C, causing abundance of species of economic value to significantly decrease south of 25° N. Finally, the response of the 20 most abundant fish species in the Gulf was modeled to estimate changes at community structure level. The simulation shows an imbalance in the function and structure of assemblages. Clearly, increasing sea temperature will bring an imbalance in the composition and the ecological function of the reef systems gradually changing the relative abundances of species. Therefore, the implementation of effective monitoring programs of communities would be an essential tool to detect future effects of global warming. O Golfo da Califórnia é uma zona de importância por sua alta biodiversidade e por ser decisivo para as pescarias artesanais no México. Existe uma preocupação das ameaças que existem sobre ele, como o aquecimento global que causou mudanças nas comunidades. Por isso, pretendeu-se estimar o possível impacto do aumento da temperatura oceânica sobre espécies chaves, como as espécies recifais. Para realizar esta estimativa, obteve-se informação da temperatura superficial oceânica (NOAA) e construiu-se um modelo de tendências de mudança de temperatura. Os dados biológicos foram obtidos de censos visuais de seis regiões do Golfo entre 2005 e 2007. Posteriormente, realizou-se um modelo lineal por passos (stepwise), com o qual se projetaram mudanças nas abundâncias e distribuição dos organismos. Estima-se que para o ano 2050 a temperatura média eleve 0.63°C; além disso, espécies de importância econômica reduzirão notavelmente sua abundância ao sul dos 25° N. Por último, modelamos a resposta de 20 espécies de peixes mais abundantes do Golfo para estimar mudanças a escala comunitária. A simulação indica desequilíbrios na função e estrutura das comunidades. O aquecimento oceânico provocará um desequilíbrio na composição e função ecológica dos ecossistemas por meio de alterações graduais nas abundâncias das espécies. Por isso, a execução na prática de programas de monitoramento das comunidades seria uma ferramenta fundamental para detectar efeitos futuros do aquecimento.

Coral reefs rival rainforest in biodiversity, but are declining in part because of disease. Tissue loss lesions, a manifestation of disease, are present in dominant Pocillopora along the Pacific coast of Mexico. We characterized tissue loss in 7 species of Pocillopora from 9 locations (44 sites) spanning southern to northern Mexico. Corals were identified to species, and tissue loss lesions were photographed and classified as those explainable by predation and those that were unexplained. A focal predation study was done concurrently at 3 locations to confirm origin of explained lesions. Of 1054 cases of tissue loss in 7 species of corals, 84% were associated with predation (fish, snails, or seastar) and the remainder were unexplained. Types of tissue loss were not related to coral density; however there was significant geographic heterogeneity in type of lesion; one site in particular (Cabo Pulmo) had the highest prevalence of predator-induced tissue loss (mainly pufferfish predation). Crown-of-thorns starfish, pufferfish, and snails were the most common predators and preferred P. verrucosa, P. meandrina, and P. capitata, respectively. Of the 9 locations, 4 had unexplained tissue loss with prevalence ranging from 1 to 3% with no species predilection. Unexplained tissue loss was similar to white syndrome (WS) in morphology, indicating additional study is necessary to clarify the cause(s) of the lesions and the potential impacts to dominant corals along the Pacific coast of Mexico.

In order to analyse the structure of the fish community in Cabo Pulmo Reef., 36 cylindrical stationary censuses (5 m radius, 15 min of observation time) were conducted in October 2003 (warm season) and February 2004 (cold season). To explore the relationship with depth and associated variables, we considered a shallow stratum ( 5.5 m; depth range was between 2 and 15 m). Species richness, number of individuals, and the indices of diversity (Shannon), evenness (Pielou) and taxonomic distinctness were computed for each census. A total of 8725 fish were recorded (3829 in the warm season and 4896 in the cold season), belonging to 62 species, included in 23 families. Thalassoma lucasanum and Chromis atrilobata were the dominant species (62.5% of total abundance, and occurrence of 97% and 72%, respectively). Conversely, 50 species had low relative abundance, 0.5), but richness, abundance and taxonomic differentiation were higher in the deeper zone. The analysis of similarity and ordination analysis did not show consistent clusters by season or depth, but suggest similarity among census of deeper zones. Most species preference for physical factors associated with deeper zones maybe the reason for the pattern observed in this study.

To define the functional groups of fish and macroinvertebrates in the Eastern Tropical Pacific (ETP), visual censuses were performed in 18 areas of four biogeographic provinces: Cortes, Mexican, Panamic and Oceanic Islands. A total of 257 fish and macroinvertebrate species were recorded, and from them, 27 morpho-functional groups (MFGs) were constructed on the basis of trophic level, maximum size, taxonomy and morphology. Biomass, richness, diversity and evenness of MFGs were calculated for each province and compared statistically; a regression analysis between taxonomic and functional diversity was conducted to observe the relationship between these two indicators. There were significant differences in all ecological indices (p 400 g/m2), associated with the influence of cold currents in the northernmost region and less fishing pressure in protected areas. A decreasing pattern of MFG richness towards the tropics was observed, which demonstrates that in the ETP, the relationship between habitat heterogeneity and species diversity has been translated into functional complexity. The Mexican province was the most functionally diverse (biomass well distributed in the MFG; H′ = 0.46 ± 0.009). Related to this, it is predicted that biomass is biased towards certain functional groups (i.e., large carnivores), which shows that the H′ index of the MFG is not a good indicator of the conservation status of ETP reefs. Finally, regression analysis suggests that functional diversity increases at low species diversity but eventually reaches an asymptote (almost all possible functions are represented).