Pacific Coast Of Mexico Research Articles

Nuevo registro de la almeja generosa Panopea globosa (Dall, 1898) (Bivalvia: Hiatellidae) en el estado de Sinaloa Mexico

Panopea globosa (Dall, 1898), a bivalve of the family Hiatellidae, is recorded for the first time in the lagoon system Altata, Navolato Municipality, Sinaloa, Mexico. During five months of sampling, 100 specimens were captured by autonomous diving at one site of the lagoon system. All the bivalves were associated with sand-lime-clay substrates at depth between 3.2 to 4 m. The sampling site was located between 24°20´- 24°35´N, and 107°20´-107°55´W. The last record for this species in the Sinaloa state is located in the Topolobampo Bay, approximately 205 km north of Altata lagoon system. This report contributes to complement the information on the bathymetric and geographic distribution for P. globosa on the Pacific coast of Mexico, and presents morphological traits of the species at the collection site.

The species of Axiidae (Crustacea: Thalassinidea) from the Pacific coast of Mexico, with a key for their identification

Axiopsis caespitosa y A. baronai, dos especies de Axiidae conocidas de la costa Pacifica de Colombia, se registran por primera vez para las aguas del Pacifico Mexicano y del Peru. Se presentan nuevas localidades de colecta de Axius vivesi asi como una clave de identificacion de los Axiidae del Pacifico Mexicano.

Natural mortality of three commercial penaeid shrimps (<em>Litopenaeus vannamei, L. stylirostris</em> and <em>Farfantepenaeus californiensis</em>) of the Gulf of California using gnomonic time divisions

The estimation of natural mortality (M) is critical for stock assessment and fisheries management. The shrimp fishery is the most valuable one in Mexico and along the Pacific Coast of Mexico, and exploitation primarily targets three species: white (Litopenaeus vannamei), blue (L. stylirostris), and brown (Farfantepenaeus californiensis). It is a sequential fishery, so an appropriate estimate of M for different life stages is required for management purposes. Typically, M is estimated from the exploited stock, which is usually composed of adults, assuming a constant value for M, and this estimate is used for studies of population dynamics, stock assessments and determinations of the status of a fishery. In this study, we estimate M-at-age (i.e. life stage) for each species using the gnomonic time division model. The gnomonic intervals correspond to the actual life stages reported in the literature, whose duration was used for model fitting. The gnomonic model showed that M declines sharply in early life stages but declines to an asymptotic value after reaching maturity, and the model provided biologically consistent estimates of M at each life stage for the three shrimp species. Such estimates may be used with confidence to model the dynamics of sequential shrimp fisheries.

Organogenesis of the digestive system in Pacific red snapper (Lutjanus peru ) larvae

This study reports the ontogenetic development of the digestive system of larval Pacific red snapper (Lutjanus peru), an important candidate species for aquaculture on the Pacific coast of Mexico. Histological sections of larvae were cut and dyed using the haematoxylin–eosin technique. The development of the digestive tract of Pacific red snapper larvae follows a general pattern of differentiation that can be divided into three stages. Stage I lasted from 1–3 days post hatching (DPH) and included the endogenous nutrition period; it was characterized by the initial differentiation of the digestive tract in preparation for the onset of exogenous feeding (3 DPH). At this time, the digestive tract was differentiated into buccopharynx, oesophagus, stomach anlage, anterior intestine, posterior intestine and a short rectum. The liver, pancreas and kidney were also present. The mouth and anus were open. Stage II occurred after first feeding, lasted for 16 days (4–23 DPH) and included both preflexion and flexion larvae. The main changes that occurred during this stage reflected the adaptation to exogenous feeding and the concomitant growth. Stage III (24–30 DPH) included post-flexion larvae and started with the appearance of the gastric glands and pyloric caeca. The presence of the gastric glands suggests that early weaning during culture trials of the Pacific red snapper larvae may be possible at this early age.

Reproduction of Mugil cephalus (Percoidei: Mugilidae) off the Central Mexican Pacific Coast

Reproduction of Mugil cephalus of the Pacific coast of Mexico was studied. Fish were captured with gill nets and cast nets; they are a common low priced product for local consumption. The study of the reproduction period and ages of first maturity helps manage the fishery. Fish were obtained from local commercial fishery from August to December 2007, January to March 2008 and November 2012 to October 2013. Size and weight, sex and gonad maturity were registered. The male:female ratio was 0.88:1. Mature organisms occurred all year round. Sexual maturation (L50) of males and females was observed at a mean size of 34.0 cm in males (4.64 years of age) and 35.0 cm in females (4.98 years of age). First maturity length (L25) was both 30.0 cm in males and females corresponding to 3.4 years of age in both cases. The allometric relationship with the hepatosomatic index was LW=4.00·10−3 · TL2.771 (r2=0.849). Condition factor indexes of Clark and Safran EW showed a maximum increment during June, August and December; Fulton and Safran TW in July and September to November. The gonadosomatic index showed its highest values from November to January. The hepatosomatic index reached its maximum values in June, July and August. The gastric repletion index reached its highest values in June, February and October. The mean oocytes diameter was 0.38 mm (range 0.22 to 0.52 mm, standard deviation=0.13). Fecundity ranged from 1’422,076 to 1’747,736 oocytes in females between ages 3 and 12 years old, and mean relative fecundity was 2,830 oocytes·g-1 (1,500 to 2,900 oocytes·g-1). This study is the base line for the fishery management of M. cephalus in Central Mexican Pacific, where the main regulations need information on the first maturity size and reproductive season.

First record and establishment of Branchiomma coheni (Polychaeta: Sabellidae) in the Atlantic Ocean and review of non-indigenous species of the genus.

Sabellidae are among the most visible polychaetes of the hard substrate fouling communities and are colonizing new geographic areas. The fouling community was surveyed in 25 shallow coastal estuaries on the Atlantic and Pacific coasts of the United States with the specific goal of detecting non-indigenous species. During surveys in 2012 and 2014, specimens of Branchiomma coheni Tovar-Hernández and Knight-Jones, 2006 were found for the first time in Tampa Bay, Florida, occurring at the same marina site (27°53'7.58"N, 82°32'2.29"W) each year and suggesting it is established here. The species was not detected at other sites surveyed in the United States, and has not been reported from the eastern Atlantic or the Mediterranean basin. Type material of B. coheni, specimens from southern Gulf of California, and specimens from the Pacific coast of Mexico, were used to corroborate identification. The transfer of this species by ships via the Panama Canal is a probable mechanism of introduction, based on the current known distribution and shipping traffic patterns. This represents the first record of the species in the Atlantic Ocean. A worldwide update of the records of this species and a list of valid species of the genus Branchiomma with notes on introduced populations are provided, as well as recommendations for accurate identification and sampling.

Did an underwater landslide trigger the June 22, 1932 tsunami off the Pacific coast of Mexico?

On June 22, 1932, a 10- to 12-m-high tsunami wave struck ~60 km off the Mexican Pacific coast. The associated earthquake that apparently produced this tsunami is questionable because of its relatively small magnitude (Ms = 6.9) to produce such tsunami heights. Historical documents, survivor testimony, tsunami catalogs, a post-tsunami survey report, together with geomorphological interpretation of the continental shelf and slope, and numerical modeling were combined to characterize the tsunami parameters. Our results suggest that recorded maximum tsunami wave height, horizontal inundation, arrival time, directivity, effects, and damage are compatible with those characteristics related to an underwater landslide tsunami. The associated landslide (slump) is 4.2 km long, 3.9 km wide, 0.448 km thick, and is located in the upper continental shelf of the Armeria Canyon. Elucidating the cause and mechanisms of the near-field 1932 tsunami would aid in considering a wider spectrum of tsunami sources in hazard mitigation programs of the Mexican Pacific coast.

A new cheilostome bryozoan genus, Abditoporella (Hippoporidridae), from the eastern Pacific.

Abditoporella dimorpha n. gen. et n. sp. is described from the Pacific coast of Mexico. It was previously misidentified as Odontoporella adpressa (Busk). Abditoporella seems to be morphologically related to Hagiosynodos Bishop & Hayward, 1989 in having a similar orifice and pseudoporous frontal shield, but is distinguished by having dimorphic zooids. A second species, Hippopodinella turrita Osburn, is reassigned to the new genus as Abditoporella turrita n. comb. Abditoporella is included in the Hippoporidridae.

Assessing the influence of artificially constructed channels in the growth of afforested black mangrove (Avicennia germinans) within an arid coastal region

Hypersaline conditions are common in sub-tropical latitudes where freshwater availability is seasonal. Hence, hydroperiod plays a crucial role in providing a suitable area for the establishment of new mangrove seedlings. The purpose of this study was to assess the function of hydrological change and irradiance in the growth of afforested black mangrove (Avicennia germinans) along the upper saltpan area by creating six channels of 1 m wide by 0.3 deep and 30 m length. All channels were constructed perpendicular to the main coastline of the Urias lagoon, Pacific coast of Mexico. Seedlings of black mangrove were planted along four of the channels. After ten months, the pore-water salinity concentration within the six channels was reduced by half. Results indicate that there were no significant differences (P > 0.05) in mangrove survival among the channels. However, the optimal growth of black mangroves was near the channels edge. The growth of mangrove seedlings planted under 50% of solar attenuation was 10 times higher as compared to mangroves under direct sunlight. This study shows the feasibility of using channels to enhance tidal flow and decrease hypersaline conditions for future afforestation endeavors in arid coastlines.

Economic incentives and overfishing: a bioeconomic vulnerability index

Bioeconomic theory predicts that the trade-offs between maximization of economic benefits and conservation of vulnerable marine species can be assessed using the ratio between the discount rate of fishers and the intrinsic rate of growth of the exploited populations. In this paper, we use this theory to identify areas of the global ocean where higher vulnerability of fishes to overfishing would be expected in the absence of management. We derive an index to evaluate the level of vulnerability by comparing discount rates and fishes' intrinsic population growth rates. Using published discount rates of countries that are reported to fish in the ocean and estimating the intrinsic population growth rate for major exploited fishes in the world, we calculate the vulnerability index for each 0.5° latitude × 0.5° longitude grid for each taxon and each fishing country. Our study shows that vulnerability is inherently high on the northeastern coast of Canada, the Pacific coast of Mexico, the Peruvian coast, in the South Pacific, on the southern and southeastern coast of Africa, and in the Antarctic region. It should be noted that this index does not account for the management regime currently in place in different areas, and thus mainly reflects the vulnerability resulting from the intrinsic life history characteristics of the fish species being targeted and the discount rates of the fishers exploiting them. Despite the uncertainties of this global-scale analysis, our study highlights the potential applications of large-scale spatial bioeconomics in identifying areas where fish stocks are more likely to be over-exploited when there is no effective fisheries management; this applies to many fisheries around the world today.

A pandemic Vibrio parahaemolyticus O3:K6 clone causing most associated diarrhea cases in the Pacific Northwest coast of Mexico.

Between September and October of 2004, more than 1230 cases of gastroenteritis due to pandemic O3:K6 strains of Vibrio parahaemolyticus (V. parahaemolyticus) were reported in the relatively small geographical area of Southern Sinaloa, a state located in Northwest Mexico. Since then, V. parahaemolyticus-associated gastroenteritis cases have gradually increased in prevalence spreading from south to north. The present study conducted an epidemiological surveillance of V. parahaemolyticus strains in both environmental and clinical samples along the Pacific coast of Sinaloa from 2011 to 2013. The genetic relatedness, serotype dominance and antibiotic resistance of isolates were investigated. A total of 46 strains were isolated from environmental samples (e.g., sediment, seawater and shrimp), whereas 249 strains were obtained from stools of patients with gastroenteritis. Nine different O serogroups and 16 serovars were identified. Serovars O3:K6 and O6:K46 were identified in both environmental and clinical strains. Whereas most environmental isolates carried the tdh gene (71.74%, 33/46), only three (6.52%) belonged to pandemic clones (O3:K6, O3:KUT and OUT:KUT). In contrast, 81.1% (202/249) of clinical isolates belonged to pandemic serotypes, with O3:K6 (tdh, toxRS/new, and/or orf8) representing the predominant serovar (97%, 196/202). This prevalence of pathogenic (tdh and/or trh positive) and O3:K6 pandemic V. parahaemolyticus isolates in this study were similar to those found from 2004 to 2010. As investigated by REP-PCR, genetic lineages of selected O3:K6 strains isolated in this study and some isolated earlier were nearly identical. Antimicrobial susceptibility testing showed that most strains (93.8%) were resistant to ampicillin but sensitive to chloramphenicol (98.8%). Multidrug resistance significantly increased from 8.6% (2004–2010) to 22.93% (2011–2013; p < 0.05). Our data indicate that pandemic O3:K6 clone has endemically established in the Pacific Coast of Mexico.

Ctenophores from the Oaxaca coast, including a checklist of species from the Pacific coast of Mexico.

Ctenophores are poorly known in the tropical eastern Pacific, including the southern coast of Mexico. Previous records of ctenophores along the Pacific coast have been provided mainly from northern waters. For the coast of Oaxaca state, their occurrence has only been mentioned before at phylum level. In this paper, we provide the first three records of ctenophores for the Oaxacan coast, which represent new records of Beroe forskalii and Bolinopsis vitrea as well as the first record of Ocyropsis maculata in the tropical eastern Pacific. Descriptions of these three species, as well as a checklist of the ctenophores from the west coast of Mexico are provided.

Paralytic toxin profile of the marine dinoflagellate Gymnodinium catenatum Graham from the Mexican Pacific as revealed by LC-MS/MS

The paralytic shellfish toxin (PST) profiles of Gymnodinium catenatum Graham have been reported for several strains from the Pacific coast of Mexico cultured under different laboratory conditions, as well as from natural populations. Up to 15 saxitoxin analogues occurred and the quantity of each toxin depended on the growth phase and culture conditions. Previous analysis of toxin profiles of G. catenatum isolated from Mexico have been based on post-column oxidation liquid chromatography with fluorescence detection (LC-FLD), a method prone to artefacts and non-specificity, leading to misinterpretation of toxin composition. We describe, for the first time, the complete toxin profile for several G. catenatum strains from diverse locations of the Pacific coast of Mexico. The new results confirmed previous reports on the dominance of the less potent sulfocarbamoyl toxins (C1/2); significant differences, however, in the composition (e.g., absence of saxitoxin, gonyautoxin 2/3 and neosaxitoxin) were revealed in our confirmatory analysis. The LC-MS/MS analyses also indicated at least seven putative benzoyl toxin analogues and provided support for their existence. This new toxin profile shows a high similarity (> 80%) to the profiles reported from several regions around the world, suggesting low genetic variability among global populations.

Spiraling into History: A Molecular Phylogeny and Investigation of Biogeographic Origins and Floral Evolution for the Genus Costus.

Rapid radiations are notoriously difficult to resolve, yet understanding phylogenetic patterns in such lineages can be useful for investigating evolutionary processes associated with bursts of speciation and morphological diversification. Here we present an expansive molecular phylogeny of Costus L. (Costaceae Nakai) with a focus on the Neotropical species within the clade, sampling 47 of the known 51 Neotropical species and including five molecular markers for phylogenetic analysis (ITS, ETS, rps16, trnL-F, and CaM). We use the phylogenetic results to investigate shifts in pollination syndrome, with the intention of addressing potential mechanisms leading to the rapid radiation documented for this clade. Our ancestral reconstruction of pollination syndrome presents the first evidence in this genus of an evolutionary toggle in pollination morphologies, demonstrating both the multiple independent evolutions of ornithophily (bird pollination) as well as reversals to melittophily (bee pollination). We show that the ornithophilous morphology has evolved at least eight times independently with four potential reversals to melittophilous morphology, and confirm prior work showing that neither pollination syndrome defines a monophyletic lineage. Based on the current distribution for the Neotropical and African species, we reconstruct the ancestral distribution of the Neotropical clade as the Pacific Coast of Mexico and Central America. Our results indicate an historic dispersal of a bee-pollinated taxon from Africa to the Pacific Coast of Mexico/Central America, with subsequent diversification leading to the evolution of a bird-pollinated floral morphology in multiple derived lineages.

Distribution of Benthesicymus tanneri Faxon, 1893 (Dendrobranchiata, Benthesicymidae) off the west coast of Mexico and notes on its morphology

A large series of specimens of Benthesicymus tanneri Faxon, 1893 (Dendrobranchiata; Benthesicymidae) was collected during an extensive survey of deep-water invertebrate fauna off western Mexico. In total, 61 males and 122 females (M:F ratio = 1:2) from 44 sampling stations were examined, considerably increasing the number of known specimens and sampling localities for this species which is widely distributed along the Pacific coast of Mexico. The collection is the largest available for this species to date and presents first records from off the west coast of the Baja California Peninsula and a slight increase of the northernmost record within the Gulf of California. On the whole, females grew larger than males. The petasma of males of different sizes and the female thelycum of Benthesicymus tanneri are illustrated. The petasma of Benthesicymus tanneri presents a ventrolateral crescent-shape process otherwide found only in Benthesicymus tirmiziae Crosnier, 1978 and in Benthesicymus bartletti S.I. Smith, 1882. A key to the four species of Benthesicymus presently known from the eastern Pacific is presented.

Distribution extension of Dasyonchocotyle dasyatis (Yamaguti, 1968) Boeger &amp;amp; Kritsky, 1989 (Monogenea: Hexabothriidae) in Dasyatis longa (Garman, 1880) (Myliobatiformes: Dasyatidae) from Sinaloa, México

The collection of 13 specimens of Dasyonchocotyle dasyatis (Yamaguti, 1968) Boeger &amp; Kritsky, 1989 on the coast of Sinaloa, México extends the geographic distribution of the species from the original locality (Hawaii, U.S.A.) eastward to at least the Pacific Coast of Mexico. The species is a parasite of Dasyatis longa (Garman, 1880), a common stingray of the tropical eastern Pacific. This species has not been reported since the original description in 1968.

Explained and unexplained tissue loss in corals from the Tropical Eastern Pacific.

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.

A literature review of the Ophiuroidea (Echinodermata) from the Pacific coast of Mexico

Despite the important effort of knowing the Ophiuroidea diversity in the Mexican Pacific, some mistakes in the taxonomic nomenclature have pervaded through time. In order to clarify the latter, a checklist based on literature review of brittle stars from the Mexican Pacific is provided. We reviewed a total of 105 references that in total summarized 125 species of brittle stars from the Mexican Pacific (112) and the Gulf of California (97), belonging to two orders, 16 families and 50 genera. These records are higher than those reported on previous studies carried out in the area. Mexico is the country with the highest number of brittle stars reported in the Tropical Eastern Pacific; this may be due to its exceptional oceanographic conditions, location and coastline extension. However, a total of 27 species reported in the literature were considered doubtful due to their general distributions and were not included in the checklist. Of the reported species, 35 have their type locality in the Mexican Pacific, corroborating the importance of the country in the Tropical Eastern Pacific in terms of Echinodermata diversity

Three Uncommon Seaweeds of the Pacific Coast of Mexico

This report describes a new record and two unusual and rare species of marine algae collected from Oaxaca, Michoacan, Jalisco and Baja California Sur at Mexican Pacific coast. Boodleopsis verticillata is the first record in the Pacific shore of Mexico, in the case of Melobesia polystromatica, this is the sixth record at tropical Pacific while Litholepis sonorensisis reported for the third time in the Gulf of California. These results suggest that the taxonomic inventory of seaweed in the Pacific coast of Mexico is not yet complete, so attention must be given to the epiphytes, and other small and delicate species that inhabit the coast of Mexico. Morphological descriptions, distributional range, reproductive stage and samples examined are included.

Morphometric variation in island and mainland populations of two lizard species from the Pacific Coast of Mexico

BackgroundBody size exerts a strong influence on the physiology, morphology, ecology, and evolution of other life history traits in vertebrates. We compared the morphometry and allometry of two lizard species (Anolis nebulosus and Aspidoscelis lineattissima) occurring on mainland and island populations on the Pacific Coast of Mexico in order to understand the effect of an insular environment on body size and other morphometric structures.ResultsResults showed that both males and females of A. nebulosus from San Pancho Island were larger in body size than those from the mainland. Moreover, males of A. lineattissima from Cocinas Island exhibited larger forms of most measured morphometric traits than those from the mainland, whereas females from both island and mainland populations did not differ in body size or in other morphometric traits analyzed. Multivariate allometric coefficients of males and females of A. nebulosus from island and mainland populations showed a lower percentage of positive allometries than in A. lineattissima, probably because the former species is highly sedentary. Island populations of both species exhibit male-biased sexual dimorphisms in body size and size-adjusted morphometric traits. In contrast to the mainland population, morphometric comparisons of body size-adjusted traits showed that male A. lineattissima were larger than females only in head length, head width, forearm length, and tibia length, whereas in A. nebulosus, sexual dimorphism was observed just in HL.ConclusionsThis study supports the hypothesis (island rule) that vertebrates on islands are larger than those of conspecifics on the mainland. In addition, sexual dimorphism observed between males and females of both species and populations could be associated with allometric growth (positive or negative) from some morphometric structures, as well as differences in the growth rates of these organisms.