Papers by David A. Paz-García
The dispersal during the planktonic larval period is a key feature to understand the metapopulati... more The dispersal during the planktonic larval period is a key feature to understand the metapopulation structure of marine fishes, and is commonly described by four general models: (1) lack of population structure due to extensive larval dispersal; (2) isolation by geographic distance, where larval connectivity decreases with increasing distance between sites in all directions (isotropy); (3) population structure without any clear geographic trend (chaotic); and (4) population structure explained by seascape approaches that explicitly incorporate the spatial and temporal variations in the direction and strength of oceanic currents via oceanographic modeling. We tested the four models in the Pacific red snapper Lutjanus peru, a key commercial species in the Gulf of California (GC), Mexico. We genotyped 15 microsatellite loci in 225 samples collected during 2015– 2016 from 8 sites, and contrasted the observed empirical genetic patterns against predictions from each model. We found low but significant levels of population structure among sites. Only the seascape approach was able to significantly explain levels of genetic structure and diversity, but exclusively within spring and summer, suggesting that this period represents the spawning season for L. peru. We showed that in the GC, the strong asymmetry in the oceanic currents causes larval con-nectivity to show different values when measured in distinct directions (anisotropy). Management tools, including marine reserves, could be more effective if placed upstream of the predominant flow. Managers should consider that oceanographic distances describing the direction and intensity of currents during the spawning period are significant predictors of larval connectivity between sites, as opposed to geographic distances.
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Sea urchins play a crucial role in the health and dynamics of reef ecosystems. Diadema mexicanum ... more Sea urchins play a crucial role in the health and dynamics of reef ecosystems. Diadema mexicanum is a dominant grazer and erosive agent of the substratum in reef environments in the eastern tropical Pacific. Its reported distribution extends from the middle of the Gulf of California (26° N) to northern Peru (6°23′ S), including oceanic islands. Here, we report the occurrence of Diadema mexicanum in Isla San Jorge (31°0′38.53″ N, 113°14′34.84″ W), the northernmost island in the Gulf of California, which extends its range an additional 600 km northward. Sea urchins, ranging in test size from 4.5 to 12.4 cm, were present at 2–6 m in October 2015. This test size was one of the largest reported for this species in the eastern tropical Pacific. Spine length in sea urchins in the upper gulf ranged from 3.3 to 15.6 cm. Variation in body size of sea urchin may reflect variation in more structurally complex reefs from isolated islands that provide shelter from predation. The reef structure of Isla San Jorge is formed by high coral cover of the scleractinian coral Porites panamensis, with an average colony height of 26.27 cm (standard error, SE ±1.58, n = 60), similar to coral reef communities of the southern Gulf of California. Although D. mexicanum is considered a great force of erosion to the substratum in reef environments in the eastern tropical Pacific, no evidence of erosion was observed at Isla San Jorge, indicating a balanced dynamic between herbivores, macroalgae, and corals.
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The study of complete mitochondrial genomes (mitogenomes) revealed different gene rearrangements,... more The study of complete mitochondrial genomes (mitogenomes) revealed different gene rearrangements, highly variable markers, and delineated clades that have aided the understanding of the evolutionary history in corals. In this study, we examined mitogenomic variation of reef-building Porites corals and designed 34 primer pairs to target high diversity regions and to amplify the complete mitogenome of a widely-distributed Indo-Pacific species of Porites (P. lobata) and two endemic species of the Eastern Pacific (P. sverdrupi and P. panamensis). All primer pairs amplified for each species and the mitogen-omes assembled yielded the same gene order as obtained from next-generation sequencing. Mitogenomic variation in Porites corals was three to ten times higher than in Acropora or Pocillopora, two other major reef builders. In contrast to these corals, the nucleotide variation in Porites species was distributed evenly along the mitogenome. Primers designed here are useful to amplify regions with the highest variation possible as well as to assemble the whole mitogenomes of different Porites species. The resulting mitogenomes should improve our understanding of evolutionary relationships, delimitation of species, and conservation within the genus Porites.
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Rising seawater surface temperatures worldwide may cause reef coral species to shift their geogra... more Rising seawater surface temperatures worldwide may cause reef coral species to shift their geographical range towards cooler environments. Information on such shifts, however, remains scarce. The scleractinian coral Porites sverdrupi (Durham, 1947) is endemic to the Gulf of California, and is considered a threatened species due to its vulnerability to local impacts, low abundance, and limited and fragmented distribution range. Although its historical range extends from the northern Gulf (29°N) to Bahía de Banderas in the south (20°N), to date only two extant populations have been reported in the central portion (25-26°N). Here we report a new record of P. sverdrupi from south of Bahía de La Paz. In 2013, colonies were observed at depths of 5–9 m close to a restored coral area south of Bahía de La Paz, which has been monitored since 2004. Events of local extinction and contraction of the distribution range were related to warm ENSO events (1982 and 2010), while expansion occurred after cold ENSO events in 2008 and 2011. Our results suggest that P. sverdrupi may tolerate the narrowest range of temperatures in its genus, and that the newly recorded range limit may be linked to the physiological limit of temperature tolerance for this species.
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Pocillopora corals are the main reef-builders in the Eastern Tropical Pacific. The validity of Po... more Pocillopora corals are the main reef-builders in the Eastern Tropical Pacific. The validity of Pocillopora morphospecies remains under debate because of disagreements between
morphological and genetic data. To evaluate the temporal stability of morphospecies in situ, we monitored the shapes of individual colonies in three communities in the southern Gulf of
California for 44 months. 23% of tagged colonies of P. damicornis changed to P. inflata morphology during this time. This switch in identity coincided with a shift to a higher frequency of storms and lower water turbidity (i.e. lower chlorophyll-a levels). Seven months after the switch, P. inflata colonies were recovering their original P. damicornis morphology. All colonies of both morphospecies shared a common mitochondrial identity, but most P. damicornis
colonies undergoing change were at a site with low-flow conditions. This is the first in situ study that document switching between described morphospecies and elucidates the influence of temporal shifts in environmental conditions on morphologically plastic responses.
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Pocillopora corals, the dominant reef-builders in the Eastern Tropical Pacific, exhibit a high le... more Pocillopora corals, the dominant reef-builders in the Eastern Tropical Pacific, exhibit a high level of phenotypic plasticity, making the interpretation of morphological variation and the identification of species challenging. To test the hypothesis that different coral morphospecies represent phenotypes that develop in different flow conditions, we compared branch characters in three Pocillopora morphospecies (P. damicornis, P. verrucosa, and P. meandrina) from two communities in the Gulf of California exposed to contrasting flow conditions. Morphological variation and branch modularity (i.e., the tendency of different sets of branch traits to vary in a coordinated way) were assessed in colonies classified as Pocillopora type 1 according to two mitochondrial regions. Our results can be summarized as follows. (1) Pocillopora type 1 morphospecies corresponded to a pattern of morphological variation in the Gulf of California. Overall, P. damicornis had the thinnest branches and its colonies the highest branch density, followed by P. verrucosa, and then by P. meandrina, which had the thickest branches and its colonies the lowest branch density. (2) The differentiation among morphospecies was promoted by different levels of modularity of traits. P. verrucosa had the highest coordination of traits, followed by P. damicornis, and P. meandrina. (3) The variation and modularity of branch traits were related to water flow condition. Morphology under the high-flow condition was more similar among morphospecies than under the low-flow condition and seemed to be related to mechanisms for coping with these conditions. Our results provide the first evidence that in scleractinian corals different levels of modularity can be promoted by different environmental conditions.
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The mitogenome of the endemic coral Porites panamensis (Genbank accession number KJ546638) has a ... more The mitogenome of the endemic coral Porites panamensis (Genbank accession number KJ546638) has a total length of 18,628 bp, and the arrangement consist of 13 protein-coding genes, 2 ribosomal RNA (rRNA) genes and 2 transfer RNA (tRNA) genes. Gene order was equal to other scleractinian coral mitogenomes.
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This study addressed the relative contribution of sexual and asexual reproduction to the genetic ... more This study addressed the relative contribution of sexual and asexual reproduction to the genetic composition of populations of two
scleractinian corals, Pocillopora damicornis and Porites panamensis, off the west coast of mainland Mexico. Reproductive indexes showed that P. damicornis reproduced both sexually and asexually; P. panamensis reproduced sexually, but colonies with an asexual origin were also observed (10–30%). Asexual reproduction is usually attributed to fragmentation caused by hurricanes; however, no significant association between reproductive index values and frequency of hurricanes was observed for either species. Environmental conditions in the Gulf of California seem to be more favorable for sexual reproduction in both species than other parts of the west coast of Mexico. This study contributes baseline information of differences in sexual and asexual reproduction in massive and branching corals.
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Caulerpa verticillata J. Agardh 1847 (Bryopsidales, Caulerpaceae) is an invasive and aggressive a... more Caulerpa verticillata J. Agardh 1847 (Bryopsidales, Caulerpaceae) is an invasive and aggressive algal species that quickly spreads by extensive blooms and overgrows coral colonies until the corals are completely covered (Lapointe and Bedford 2010).Like other species in this genus, this alga has the potential to impact ecosystem diversity and function of coral reefs (Fernández and Cortés 2005; Kružić et al. 2008). In the tropical Eastern Pacific, this species has been reported only in Panama at 8°N and in the Mexican Pacific at 19°N (Mateo-Cid and Mendoza-González 1991; Pérez-Justavino et al. 2010). Little is known about the spread of this alga. In January 2010, C. verticillata (Fig. 1a) was recorded for the first time covering a few square meters in rocky areas at 2 m depth at Esterito (24°10′36.46″N, 110°18′21.16″W) and La Concha (24°12′4.72″N, 110°18′2.24″W), in the southwestern part of the Gulf of California. One year later, diver and aerial surveys revealed that the alga had increa ...
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Density banding provides a record of performance of coral colonies over time and across environme... more Density banding provides a record of performance of coral colonies over time and across environments, 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, calcification rate is hypothesized to be different for each gender. To evaluate differences in skeletal growth between 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 measured using photo-densitometry of X-radiographs. Extension 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 calcification differently in male and female colonies.
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High predation by the corallivore gastropod Jenneria pustulata was observed in July 2011 in a hig... more High predation by the corallivore gastropod Jenneria pustulata was observed in July 2011 in a high-latitude reef at Bahía de Los Ángeles in the northern Gulf of California. Porites panamensis corals were infested by 15 to 40 sea snails per colony (22 ± 7.25 ind/0.1 m of Porites surface). Coral colonies were 20-30 cm tall and the average size of the sea snails were 1.7 cm (SD ± 0.238, N =152). These data indicate a change in the daily pattern of movement and feeding of the gastropod in this reef. Despite high density of J. pustulata on the reef, no soft corals were observed as damaged by the sea snail.
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Changes in sea-water temperature on coral reefs can cause mass coral bleaching events resulting i... more Changes in sea-water temperature on coral reefs can cause mass coral bleaching events resulting in widespread coral mortality. In the last five years, coral communities of the Gulf of California have had bleaching events caused by temperatures below 19 °C. A cold water bleaching event occurred in February 2011, providing an opportunity to assess the bleaching response and verify bleaching susceptibility among Pocillopora morphospecies. Across three surveyed locations, 84% of corals showed visual signs of bleaching to a minor or major degree. The southern-most location was the least affected by cold water bleaching; possibly due to the exposition of high levels of wave and current that could diminish the effects of high sea surface temperatures, acclimation of colonies to seasonal upwelling of cold water from the California current, and the frequency of cold-resistant Symbiodinium glynni in coral colonies, which all suggest adaptation to harsh temperature conditions. High significant bleaching to cold water was found between P. damicornis and the rest of Pocillopora morphospecies (P. verrucosa, P. meandrina, and P. capitata). High bleaching susceptibility of P. damicornis could be due to intra-specific differences in symbiont or genotypic variation among colonies, and other factors such as local water circulation and/or flow velocity that can also influence bleaching and morphological plasticity in Pocillopora corals. A better understanding of bleaching events and the ability of corals to respond to periods of thermal stress (cold or warm) will allow managers to target particular reef ecosystems for protection.
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Genetic connectivity was studied in two scleractinian corals, Pocillopora damicornis ( branching ... more Genetic connectivity was studied in two scleractinian corals, Pocillopora damicornis ( branching and broadcast spawner) and Porites panamensis (massive and brooding type), along the Pacific coast of Mexico. Allelic diversity between adults and juveniles, the latter recruited after the El Niño–Southern Oscillation (ENSO) 1997 – 1998 event, was determined, and level of genetic connectivity among populations was assessed. There were no significant differences in allelic diversity between adults and juveniles from the same location. Seascape spatial genetic analysis suggested two or three clusters, depending on the species: (1) Bahías de Huatulco, (2) south of the Baja California Peninsula and Bahía de Banderas, and (3) locations in the Gulf of California. The most important barrier to gene flow was detected between Bahía de Banderas and Bahías de Huatulco and corresponds with a major coastal stretch of sandy beaches and lagoons. Moderate to high gene flow was found inside and at the entrance of the Gulf of California ( Nem = 62 – 250), possibly favored by seasonal circulation patterns and sexual reproduction. In contrast, low gene flow was observed between southern populations and the rest of coastal Mexico ( Nem < 1.7) based on high local recruitment and habitat discontinuity. A close genetic relationship of corals from the southern part of the Baja California Peninsula and severely damaged Bahía de Banderas coral communities confirmed that exchange of propagules could have taken place between the localities after the ENSO 1997–1998 event. Despite different reproductive strategies, both species showed similar patterns, suggesting the importance of surficial currents and habitat discontinuity to predict connectivity among coral reefs.
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Genetic structure was studied in the coral Pocillopora damicornis in three areas of coral develop... more Genetic structure was studied in the coral Pocillopora damicornis in three areas of coral development of the Mexican Pacific (MP). Specimens were collected from six localities: El Portugues and Punta Gaviotas located inside the Gulf of California (GC), Punta Arenas and Isla Redonda from the entrance of GC, and Las Dos Hermanas and La Entrega in the south of the MP. Exclusive genotypes were observed in the northern and southern populations. Genetic variation was similar along the MP, although slight higher variation was observed in the southern populations. Most of the populations presented significant deficits heterozygotes. These deficiencies could be due to the predominance of the asexual reproduction by fragmentation, localized sexual reproduction, inbreeding and/or Wahlund effect among localities, and different mortality events by natural disturbances. Cluster analysis based on genetic distance showed three groups by geographical proximity: two populations inside the GC, those ones located in the entrance of the GC, and two populations located at the south of the MP. Mean significant FST value (FST = 0.153) indicated a genetic structure. Differences in sexual and asexual reproduction among the localities coupled with local recruitment and currents patterns are possibly generating the genetic structure observed in the populations of P. damicornis in the MP.
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Cnidarian-algal symbioses are important in sustaining coral reef ecosystems. Little is known abou... more Cnidarian-algal symbioses are important in sustaining coral reef ecosystems. Little is known about how these associations respond ecologically and evolutionarily to environmental change. We examined the diversity of zooxanthellae populations in two morphotypes of Porites panamensis in the southern Gulf of California. Additionally, we analyzed the host genetic information by allozyme electrophoresis in order to demonstrate if the species of symbiont corresponds with the genotype and/or morphotype of the host individual. The specimens (N = 20) were collected from shallow coral communities (1-2 m). Symbiodinium C66a associated with columnar colonies while C66 occurred commonly in colonies with mounded or massive morphologies. Both colony forms associated with C1. Higher allelic diversity and different symbiont clades were found in columnar colonies, relative to massive colonies in the same habitat. Certain host genotypes associated specifically with a particular Symbiodinium type. These preliminary findings indicate that host-symbiont co-evolution is important in shaping partner combinations and that the mode of symbiont acquisition by maternal or vertical transmission facilitates this process.
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Genetic structure was studied in the brooding coral Porites panamensis along of the Mexican Pacif... more Genetic structure was studied in the brooding coral Porites panamensis along of the Mexican Pacific (MP). We collected in three locations inside of the Gulf of California, two zones at the entrance of the Gulf, and one location at south of MP. Exclusive genotypes in two of six allozyme loci were observed in northern (LGG-1DE and LGG-1EE) and southern (EST-1AA and EST-1AB) populations. All populations presented significant deficits of heterozygotes. These deficits could be for different recruitment and temporal events of larvae expulsion along the MP, high local recruitment and inbreeding by limited dispersion of larvae, and differentmortality events by natural disturbances. Cluster analysis of genetic distance showed three groups by geographic proximity: the populations from inside of the GC, two populations from the entrance of the gulf, and the southern population of MP. AMOVA indicated a significant differentiation among the three groups (11.93%, p = 0.016). Mean significant FST value (FST = 0.104, p < 0.01) reveled a genetic structure. The oceanic patterns coupled with restricted dispersion of this brooding coral species could be the principal factor that generating the genetic structure observed.
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Genetic variation was analyzed to determine whether two morphotypes, a massive and columnar form,... more Genetic variation was analyzed to determine whether two morphotypes, a massive and columnar form, of Porites panamensis found together in the Gulf of California (GC) were genetically differentiated. Levels of genetic variation were similar between morphotypes and no fixed alleles were detected between them. Levels of sexual reproduction were high, as indicated by ratios NG:N 0.76-1.00 and GO:GE 0.71-1.00 for both morphotypes. Analysis of Molecular Variation (AMOVA) indicated the greatest significant genetic variation within populations (97.85%) and among populations within morphotypes levels (2.63%), but not among morphotypes (-0.47%, p = 0.6826). Mean significant FST values for columnar (FST = 0.024) and massive (FST = 0.043) suggest that both morphotypes had moderate genetic structure within their populations. The number of migrants per generation (Nem) showed differences within morphotype populations (columnar 4.65-31 and massive 2.65-9.75). The lower genetic differentiation among morphotypes indicates that it is likely that they frequently interbreed. However, we observed a genetic differentiation among the populations of the morphotypes of P. panamensis in the north and central part of the GC, while in the south of the GC the populations of both the morphotypes are more similar and may constitute a population that is more genetically homogeneous. North-central coral communities from the GC are characterized by extreme temperature and nutrients conditions and adaptation to this stress environment may be reflected in our genetic data.
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Papers by David A. Paz-García
morphological and genetic data. To evaluate the temporal stability of morphospecies in situ, we monitored the shapes of individual colonies in three communities in the southern Gulf of
California for 44 months. 23% of tagged colonies of P. damicornis changed to P. inflata morphology during this time. This switch in identity coincided with a shift to a higher frequency of storms and lower water turbidity (i.e. lower chlorophyll-a levels). Seven months after the switch, P. inflata colonies were recovering their original P. damicornis morphology. All colonies of both morphospecies shared a common mitochondrial identity, but most P. damicornis
colonies undergoing change were at a site with low-flow conditions. This is the first in situ study that document switching between described morphospecies and elucidates the influence of temporal shifts in environmental conditions on morphologically plastic responses.
scleractinian corals, Pocillopora damicornis and Porites panamensis, off the west coast of mainland Mexico. Reproductive indexes showed that P. damicornis reproduced both sexually and asexually; P. panamensis reproduced sexually, but colonies with an asexual origin were also observed (10–30%). Asexual reproduction is usually attributed to fragmentation caused by hurricanes; however, no significant association between reproductive index values and frequency of hurricanes was observed for either species. Environmental conditions in the Gulf of California seem to be more favorable for sexual reproduction in both species than other parts of the west coast of Mexico. This study contributes baseline information of differences in sexual and asexual reproduction in massive and branching corals.
morphological and genetic data. To evaluate the temporal stability of morphospecies in situ, we monitored the shapes of individual colonies in three communities in the southern Gulf of
California for 44 months. 23% of tagged colonies of P. damicornis changed to P. inflata morphology during this time. This switch in identity coincided with a shift to a higher frequency of storms and lower water turbidity (i.e. lower chlorophyll-a levels). Seven months after the switch, P. inflata colonies were recovering their original P. damicornis morphology. All colonies of both morphospecies shared a common mitochondrial identity, but most P. damicornis
colonies undergoing change were at a site with low-flow conditions. This is the first in situ study that document switching between described morphospecies and elucidates the influence of temporal shifts in environmental conditions on morphologically plastic responses.
scleractinian corals, Pocillopora damicornis and Porites panamensis, off the west coast of mainland Mexico. Reproductive indexes showed that P. damicornis reproduced both sexually and asexually; P. panamensis reproduced sexually, but colonies with an asexual origin were also observed (10–30%). Asexual reproduction is usually attributed to fragmentation caused by hurricanes; however, no significant association between reproductive index values and frequency of hurricanes was observed for either species. Environmental conditions in the Gulf of California seem to be more favorable for sexual reproduction in both species than other parts of the west coast of Mexico. This study contributes baseline information of differences in sexual and asexual reproduction in massive and branching corals.