Ecuadorian Pacific Research Articles

Selectivity of gillnets for the capture of Selene peruviana and Peprilus medius in the Ecuadorian Pacific

In the Ecuadorian Pacific, Selene peruviana and Peprilus medius are target species for artisanal fishing caught with gillnets that constitute an important fishery resource for local consumption, given that they are highly valued species due to their low cost and their contribution of high biological value protein. However, no studies have determined selectivity in capturing these species. This study evaluates the selectivity of monofilament surface gillnets with mesh sizes of 3" (7.62 cm) and 3 ½" (8.89 cm), mostly used by artisanal fishers. Data were obtained from several fishing operations within the coastal zone of 8 nautical miles (nm) in Manabí, Ecuador, in 2017, between 6:00 pm and 6:00 am. Selectivity parameters and curves were evaluated through multi-model analysis using the SELEC method. The lognormal model showed the best fit with modal lengths of 24.23 and 21.96 cm for S. peruviana and P. medius, respectively, and selection factors of 3.23 and 3.11. The optimal mesh sizes were calculated at 7.20 and 6.91 cm, respectively, which are smaller than those commonly used by most local artisanal fishers. Therefore, it can be inferred that the size distribution of the captured species follows a lognormal distribution, suggesting that gillnets have a higher probability of capturing larger fish.

Life history traits of the pelagic thresher shark (Alopias pelagicus) in the Eastern-Central Pacific Ocean

Life history traits, such as age, growth, and maturity, are essential in fisheries management. However, Alopias pelagicus lacks the age and growth parameters in Ecuador, despite being the elasmobranch species with the highest number of landings in the country. Therefore, the aim of this work was to estimate the age, growth, and maturity parameters of A. pelagicus in the Ecuadorian Pacific. For this, field trips were carried out in Playita Mía, Manta, Ecuador from June 2021 to May 2022. In these field trips, the vertebrae of 304 individuals were collected. Frequentist and Bayesian multimodels (von Bertalanffy, Gompertz, and Logistic) were used to estimate age and growth parameters. A logistic model was used to estimate the mean size at maturity. The inflection point in males was estimated from a modified logistic model. The best fit was given by the Bayesian logistic model for combined sex (L∞ = 168.16 cm PCL, L0 = 73.76 cm PCL, g = 0.34 year−1) according to leave-one-out-information-criterion (LOOIC). Age and length at maturity were estimated at 5.12 years and 141.28 cm PCL, respectively in males. The inflection point was estimated at 133.67 cm PCL. The information presented here is necessary for future demographic analyses. It is necessary that future studies can estimate the age and length at maturity in females.

Age and growth of the blue shark Prionace glauca (Linnaeus, 1758) in the Ecuadorian Pacific: Bayesian multi-models.

The blue shark Prionace glauca plays a critical role as a predator in marine ecosystems but is threatened by by-catch. To obtain more precise biological data, a Bayesian approach was used, and 536 vertebrae samples collected during 1 year at the landing stage called "Playita Mía" Manta, Ecuador, were analysed. The objective was to estimate the age and growth parameters of the species. The size of the specimens varied between 116 and 310 cm in total length (TL). Using a Bayesian approach based on the Markov Chain Monte Carlo (MCMC) method, growth parameters were evaluated. The von Bertalanffy model was the one that best fitted the data and provided more adequate estimates (females: = 325.50 cm, = 53.23 cm, and k = 0.12 years; males: = 331.47 cm, = 51.59 cm, k = 0.12 years -1; combined sexes: = 329.65 cm, = 53.64 cm, k = 0.11 year-1). The results indicated that females and males have a similar growth, and that the species has a slow growth. Further studies using multi-model Bayesian approaches and covering a broader range of sizes in the Pacific Ocean are suggested. These studies will provide crucial information for the management and conservation of this species.

Reproductive biology of the crocodile shark, Pseudocarcharias kamoharai, in the Ecuadorian Pacific Ocean

The crocodile shark, Pseudocarcharias kamoharai, is frequently caught by the artisanal fleet of Ecuador. However, updated official records concerning its landings and knowledge regarding its reproductive biology and ecological traits are scarce in the Tropical Eastern Pacific Ocean. Therefore, this study aimed to describe the reproductive biology of P. kamoharai and determine the capture composition of immature and mature individuals in Santa Rosa, Ecuador. Samples were collected from June 2012–May 2013 and June 2017–May 2018. 408 sharks were collected including 202 females ranging from 50 to 117 cm in total length (TL), and 206 males ranging from 72.5 to 110 cm TL. The sex ratio in adults was 1F:1M, similar to the fetus’s ratio of 0.9F:1M. Histotrophy in the uteri of mature females was recorded for the first time. Size at maturity (L50) was estimated at 91.2 cm TL for females; hence, 88% (n = 177) were mature. While for males, L50=84.8 cm TL; thus, 84% (n = 174) were mature. Gravid females were observed from February to November, and fetuses had different sizes without a growing trend pattern. Thus, gestation and time of birth could not be defined. Size at birth was 45.5 cm TL and fecundity was four fetuses per litter, two for each uterus. In conclusion, this species is susceptible to overfishing due to its low biological productivity. The information generated in this study supports creating a fishery management plan for future conservation.

Reproductive cycle and sexual maturity size of landed Selene peruviana (Perciformes: Carangidae) on the coasts of the Ecuadorian Pacific

The Peruvian moonfish (Selene peruviana) is an important fisheries resource that is landed in the main fishing harbors of Ecuador. At the local level, little information is available regarding the biology of this species, which hinders the development of management plans. The present study evaluates the reproductive characteristics of S. peruviana such as the size at sexual maturity and reproductive cycle. Specimens were obtained from artisanal and industrial catches from January 2017 to December 2018. The morphometric characteristics, sex, and maturity stage of 886 specimens were determined, and the gonadosomatic index (GSI), hepatosomatic index (HSI), and relative condition factor (Kn) were estimated. The length-weight relationship and length at sexual maturity (L50) were evaluated with an allometry equation and multi-model analyses, respectively. The mean capture size (total length, TL) was 23.62 cm for males and 22.97 cm for females. A sex ratio (M:F) of 0.70:1.00 (χ2 = 26.28, P < 0.05) was obtained. The allometric factor of the length-weight relationship for both sexes (b) was 2.63 (t = 12.16, P < 0.05), and the coefficient of determination (r2) was 0.89, which suggests that negative allometric growth was present. The L50 (TL) was estimated to be 22.61, 23.86, and 23.27 cm for males, females, and sexes combined, respectively. The monthly GSI, HSI, and Kn values were significantly different (K-W, P < 0.05) among study months. The maximum GSI values were observed in February and March, which constituted the period of highest reproductive activity. The HSI and Kn values exhibited similar trends. The size at sexual maturity was similar to the average catch size, which could indicate that S. peruviana is currently at the limit of its optimal catch size.

Size structure, length-body mass relationship, and relative condition factor of the crocodile shark, Pseudocarcharias kamoharai, in the Southeastern Pacific Ocean, Ecuador

The crocodile shark, Pseudocarcharias kamoharai, is a species of ecological and economic importance in the marine ecosystems of Ecuador. Although it is a fishery resource for local consumption, biological and ecological information and appropriate fishery management are needed to allow its sustainable use. This research aimed to analyze the population’s size and total body mass structures, determine the length-body mass relationship, and the relative condition factor of the crocodile shark in the Ecuadorian Pacific Ocean. Samples were collected from June 2012 to May 2013 and from June 2017 to May 2018 in Santa Rosa, Ecuador. The size of females (n=202) ranged from 50 to 117 cm total length, while males (n=206) ranged from 72.5 to 110 cm TL. The total body mass for females was between 700 and 7 100 g and from 2 000 to 5 000 g for males. Significant differences were observed between sizes (Mann Whitney test, W= 55 018.50; p < 0.05) and body mass for females and males (W= 56 338.50; p < 0.05). Length-body mass relationship parameters for the combined sexes were a=0.015, b=2.70, R2=0.79; for females: a=0.045, b=2.48, R2=0.80; and for males a=0.098, b=2.28, R2=0.66. In all cases, length-body mass relationship patterns were hypoallometric. The relative condition factor for combined sex ranged between Kr=0.81 and 1.34 (Kr= 0.84–1.34 for females and Kr= 0.81–1.30 for males), demonstrating that this species had a healthy nutritional condition. This study investigates the fishery biology of the species in this region of the Pacific Ocean for a future management plan.

Reproductive biology of the bigeye thresher, Alopias superciliosus, in the Tropical Eastern Pacific Ocean

The bigeye thresher, Alopias superciliosus, is a commercially important species caught as a target and bycatch in Ecuadorian fisheries by artisanal fleets. However, information on its biology and ecology in the Southeastern Pacific Ocean is scarce and regulatory measures are lacking. It is considered a vulnerable species with a decreasing population trend. In the present study, we report on the reproductive biology of A. superciliosus landed in the Ecuadorian Pacific Ocean. A total of 133 specimens (46% females and 54% males) were examined from October 2012 to September 2013. The size range of females and males was 119–402 cm total length (TL, x̄ = 280.7 ± 50.3) and 132–341 cm TL (x̄ = 277.3 ± 47.3), respectively. The sex ratio (0.9 F:1.0 M) was not significantly different from the expected ratio 1:1; the sex ratio in embryos was not different either (1 F:1.0 M). The mean size at maturity (L50) was estimated at 315.7 cm TL for females and 275.2 cm TL for males. Gravid females were recorded from April–September 2013 and ranged between 322 and 361 cm TL (x̄ = 336.6 ± 13.7). Fecundity was two embryos for each female and one embryo per uterus, and the size at birth was 122 cm TL after a gestation of twelve months. The births probably occurred in August. A description of three stages of embryos is included. The present study provides biological information on Alopias superciliosus, which can help in the development of fishery management plans for the conservation of the species.

Reproductive dynamics of Peprilus medius captured in the Ecuadorian Pacific

In Ecuador, Peprilus medius is an important fishery resource whose destination is for local consumption and export. There are few local studies on its reproductive biology, and its capture is not regulated. Therefore, this study evaluates the most relevant aspects of its reproductive activity. Samples were obtained monthly from January to December 2017 from the capture of the purse seine fleet and the artisanal gillnet fleet landing near Manta. The morphometric analysis included the length-weight relationship, estimated using the allometry equation. The size at sexual maturity is based on the L50 criterion; the reproductive cycle was determined according to the monthly analyses of the gonadosomatic index (GSI), hepatosomatic index (HSI), and relative condition factor (Kn). A total of 334 specimens were analyzed, with average sizes of 22.0, 21.87, and 21.91 cm of total length (TL), for males, females, and combined sexes, respectively. Sex ratio was 1.17M: 1F (P &gt; 0.05), while the length-weight relationship showed negative allometric growth for both males and females (b = 2.58; CI95% 2.48-2.72). Size at sexual maturity L50 was estimated at 21.84 and 21.23 cm TL for males and females, respectively. The GSI and HSI values and Kn showed significant differences among months (P &lt; 0.05), with a marked seasonality during the single reproductive period. Mean size at first capture of 21 cm TL is recommended.

Quality of life of cutaneous leishmaniasis suspected patients in the Ecuadorian Pacific and Amazon regions: a cross sectional study

BackgroundYearly, up to 1 million patients worldwide suffer from cutaneous leishmaniasis (CL). In Ecuador, CL affects an estimated 5000 patients annually. CL leads to reduced Health Related Quality of Life (HRQL) as a result of stigma in the Asian and Mediterranean contexts, but research is lacking for Ecuador. The objective of this study was to explore the influence of CL suspected lesions on the quality of life of patients in the Pacific and Amazon regions.MethodsPatients for this study were included in the Amazonian Napo, Pastaza, and Morona Santiago provinces and the Pacific region of the Pichincha province. Participating centers offered free of charge CL treatment. All patients suspected of CL and referred for a cutaneous smear slide microscopy examination were eligible. This study applied the Skindex-29 questionnaire, a generic tool to measure HRQL in patients with skin diseases. All statistical analysis was done with SPSS Statistics version 28.ResultsThe skindex-29 questionnaire was completed adequately by 279 patients who were included in this study. All patient groups from the Amazon scored significantly (P < 0.01) higher (indicating worse HRQL) on all the dimensions of the Skindex-29 questionnaire than Mestizo patients from the Pacific region. The percentage of patients with health seeking delay of less than a month was significantly (P < 0.01) lower in the Amazon region (38%) than in the Pacific (66%).ConclusionsThe present study revealed that the influence of suspected CL lesions on the HRQL of patients in the Ecuadorian Amazon and Pacific depends on the geographic region more than on patient characteristics such as gender, age, number of lesions, lesion type, location of lesions, health seeking delay, or posterior confirmation of the Leishmania parasite. The health seeking delay in the Amazon might result from a lack of health infrastructure or related stigma. Together, the impaired HRQL and prolonged health seeking delay in the Amazon lead to prolonged suffering and a worse health outcome. Determinants of health seeking delay should be clarified in future studies and CL case finding must be improved. Moreover, HRQL analysis in other CL endemic regions could improve local health management.

Catch Composition, Seasonality, and Biological Aspects of Sharks Caught in the Ecuadorian Pacific

Although sharks have a fundamental role in maintaining the balance of aquatic ecosystems, exerting a great influence on lower levels of the food chain, their populations are declining worldwide due, to a large extent, to overfishing. Of the 64 species registered in Ecuador, from January to December 2019, 19 species were recorded in Manta from the 15,455 captured individuals, with the family Carcharhinidae being the most abundant in the catches (69.4%), and the most abundant species was Prionace glauca (57.9%). Regarding threatened species, such as Carcharhinus longimanus, Sphyrna lewini, and Sphyrna zygaena, a greater presence of immature specimens was observed in landings. However, information on the composition and biological aspects of shark species in the Ecuadorian Pacific is very scarce. Therefore, research on the characteristics of life history (age, growth, and maturity) are of utmost importance for the stock assessments that are being exploited, especially in developing countries, where this information is lacking, causing inadequate management of fishery resources.

Distribución espacial de diversidad y abundancia de copépodos planctónicos en el Pacifico ecuatoriano durante octubre del 2017

The spatial distribution, abundance and diversity of pelagic copepods and their relationship with hydrographic variables was studied at 19 stations in the Ecuadorian Pacific in October 2017. Collections were made by surface trawling, with a standard net of 30 cm mouth diameter and 220 ? mesh size. Sixty-three species of copepods were identified, with abundance ranging from 173 org.m-3 to 2246 org.m-3 and diversity ranging from 2.13 to 5.40 bit.org-1. Generally, copepod diversity and abundance were higher near the mainland and the Galapagos Islands. According to the ACC, the variable that most influenced distribution, abundance and diversity was the SST, an environmental parameter that explains the dynamics of the copepod community. In general, the distribution, diversity and abundance of copepods was largely related to the development of the equatorial front displaced south of the coast of Ecuador and to upwelling processes controlled by coastal and oceanic currents. Most of the identified species are common in tropical and subtropical water masses of neritic and oceanic environment.

A fresh look at Cosmetus Perty, 1833 (Opiliones: Cosmetidae), with new synonymies and description of two new species from Colombia.

Cosmetus Perty, 1833 is the type genus of the most diverse subfamily of Laniatores, Cosmetinae. The genus currently includes 22 valid species with a disconnected distribution, including coastal forests of NE Brazil, dry forests of the Ecuadorian Pacific, Choc-Darien moist forests and the Venezuelan Andes. The morphology among species in the genus is quite variable, but they share almost exclusively the fused spine in area III. The type species Cosmetus varius is little known due to few, poor quality illustrations, a vague type locality, and lost type material, and was misidentified by Koch in 1840, making it difficult to define or even taxonomically revise the genus. Herein we: (1) provide distribution maps for nominal Cosmetus species; (2) recognize the poorly defined type species C. varius as a species occurring in central-eastern Bahia, agreeing with the itinerary of Spix and von Martius; (3) synonymize three other species from central-eastern Bahia with C. varius; (4) provide images of the external morphology of three Brazilian species of the genus; and (5) describe two new sympatric species from the Colombian Pacific region (Choc-Darien moist forest), thus representing the first report of the genus for the country. Both Colombian species, Cosmetus acanti sp. nov. and Cosmetus villarreali sp. nov., have similar external morphology but are remarkably different in genital morphology. Morphological evidence indicates that Cosmetus may be an artificial group. However, given the chaotic taxonomy of the family Cosmetidae, and the deep intertwining of nomenclature, we do not know at the moment where each of those species should be classified.

Dietary ecology and trophic level of adults of the Chilean angel shark Squatina armata Philippi 1887 in the Central-Eastern Pacific Ocean

As top predators, sharks play an important role in the regulation of marine ecosystems. This study provides information on the feeding ecology and trophic level of the Chilean angel shark Squatina armata in the central-eastern Pacific Ocean. A total of 320 sharks were caught by the artisanal fishery in the Ecuadorian Pacific Ocean and landed in Manta (Ecuador) between November 2003 and October 2004, in which such specimens measured 66 cm to 98.5 cm of total length (TL). The prey included bony fish, elasmobranchs, mollusks, and crustaceans. According to the Prey-Specific Index of Relative Importance (%Psiri), the kolibri shrimp Solenocera agassizii, lizardfish Synodus spp., and peanut rock shrimp Sicyonia picta were the main prey in the diet of S. armata. The sharks which belonged to size I (65–80 cm TL), consumed mostly drum Larimus spp., S. agassizi, and bignose conger Rhynchoconger nitens; while for size II (80–95 cm TL) and size III (95–109 cm TL), sharks fed mostly on S. agassizi, Synodus spp., and S. picta. The results showed that S. armata feeds on the same prey items all year round and it does not display dietary changes. This shark species is a selective predator with functions of a mesopredator (trophic level = 3.20–5.20). It could be classified as mainly piscivorous and carcinophagus, in which this shark species searches for food mainly in benthic and coastal areas. This study highlights the scarcity of knowledge regarding the biology and ecology of S. armata in the central-eastern Pacific Ocean. Additionally, it underlines the need to produce information that will allow adequate management and conservation measures to be implemented for this species by understanding their important feeding spots in coastal areas of Ecuador.

Reproductive biology aspects of Alopias pelagicus and A. superciliosus (Lamniformes: Alopiidae) in the Ecuadorian Pacific

ABSTRACT The reproductive biology of thresher shark species of the Ecuadorian Pacific was analysed based on 1236 specimens of Alopias pelagicus (711 females and 525 males) and 354 of A. superciliosus (164 females and 190 males) landed in “Playita Mía”, from January to December of 2019. The length of A. pelagicus females ranged between 67.2 and 184 cm PCL (precaudal length) and the males between 69.0 and 178.4 cm PCL, A. superciliosus registered a minimum and maximum size of 76.0 and 202.2 cm PCL for females and 94.0 and 204.8 cm PCL for males. The most frequently captured size class for A. pelagicus was 147.2−157.2 cm PCL and for A. superciliosus was 156.0-166.0 cm PCL. The sex ratio (F:M) for A. pelagicus and A. superciliosus was 1.35F:1M and 0.86F:1M respectively. For A. pelagicus males the inflection point of the clasper length adjustment, was 134.2 cm PCL and size at first sexual maturity (L 50 ) was estimated at 136.0 cm PCL. For A. superciliosus males the inflection point of the clasper length adjustment, was 136.8 cm PCL, and the first sexual maturity (L 50 ) was estimated at 138.7 cm PCL.

Anopheline and human drivers of malaria risk in northern coastal, Ecuador: a pilot study

BackgroundUnderstanding local anopheline vector species and their bionomic traits, as well as related human factors, can help combat gaps in protection.MethodsIn San José de Chamanga, Esmeraldas, at the Ecuadorian Pacific coast, anopheline mosquitoes were sampled by both human landing collections (HLCs) and indoor-resting aspirations (IAs) and identified using both morphological and molecular methods. Human behaviour observations (HBOs) (including temporal location and bed net use) were documented during HLCs as well as through community surveys to determine exposure to mosquito bites. A cross-sectional evaluation of Plasmodium falciparum and Plasmodium vivax infections was conducted alongside a malaria questionnaire.ResultsAmong 222 anopheline specimens captured, based on molecular analysis, 218 were Nyssorhynchus albimanus, 3 Anopheles calderoni (n = 3), and one remains unidentified. Anopheline mean human-biting rate (HBR) outdoors was (13.69), and indoors (3.38) (p = 0.006). No anophelines were documented resting on walls during IAs. HBO-adjusted human landing rates suggested that the highest risk of being bitten was outdoors between 18.00 and 20.00 h. Human behaviour-adjusted biting rates suggest that overall, long-lasting insecticidal bed nets (LLINs) only protected against 13.2% of exposure to bites, with 86.8% of exposure during the night spent outside of bed net protection. The malaria survey found 2/398 individuals positive for asymptomatic P. falciparum infections. The questionnaire reported high (73.4%) bed net use, with low knowledge of malaria.ConclusionThe exophagic feeding of anopheline vectors in San Jose de Chamanga, when analysed in conjunction with human behaviour, indicates a clear gap in protection even with high LLIN coverage. The lack of indoor-resting anophelines suggests that indoor residual spraying (IRS) may have limited effect. The presence of asymptomatic infections implies the presence of a human reservoir that may maintain transmission.

Satellite radar interferometry for assessing coseismic liquefaction in Portoviejo city, induced by the Mw 7.8 2016 Pedernales, Ecuador earthquake

The Portoviejo city, located in the central part of the Ecuadorian Pacific Coast (province of Manabi), was severely affected during the Pedernales Mw 7.8 earthquake of April 16, 2016, accompanied by coseismic liquefaction phenomena that induced processes of ground subsidence, lateral spreading, sinkhole, and sand boils. The present study proposes the detection and delimitation of the areas affected by the relief deformation, associated liquefaction processes, which occurred in the urban area of Portoviejo city and especially in the Zero Zone of greater destruction after the earthquake, through the application of Differential Interferometry Synthetic Aperture Radar (INSAR) methodology, using Sentinel 1A satellite images, plus the support of geological–geotechnical data obtained from boreholes and standard penetration tests to evaluate the liquefaction potential of the layers of the subsoil based on the Potential Liquefaction Index, considering the seismic scenario of amax 0.5 g for the urban area and the Zero Zone. This procedure allowed the delimitation of areas of high seismic risk for the proper coordination and management of the construction and reconstruction processes in the city of Portoviejo and specifically in the Ground Zero.

Certificación turística como herramienta de diferenciación clave para las playas: Caso Playa Chipipe. Salinas- Ecuador.

El turismo de sol y playa sigue siendo de gran trascendencia mundial como motivador de viajes turísticos. La zona costera del pacifico ecuatoriano, posee una diversidad de playas con atractivos naturales y culturales que favorecen la motivación de los turistas. El incremento de visitantes, sumado a la saturación de planta turística y demás componentes del sistema turístico pueden ocasionar serios impactos negativos, por lo cual implica una gestión orientada con criterios de sostenibilidad que garantice mantener los estándares de calidad de los servicios y sus recursos. La investigación consistió en evaluar la playa Chipipe del cantón salinas apoyada en los parámetros de la norma ecuatoriana INEN 2631, para su certificación como primera playa turística certificada en el Ecuador. La metodología utilizada se fundamentó básicamente en el trabajo de campo a través de técnicas de observación y recopilación de información directa de los actores locales involucrados en el sector. Se obtuvo como resultado que la playa de Chipipe aplica para una certificación de clase “C” según la norma, cumpliendo con los indicadores de autogestión, seguridad, zonificación e infraestructura.

Data on phase and chemical compositions of black sands from "El Ostional" beach situated in Mompiche, Ecuador.

Data revealing the phase and chemical compositions of natural black sands from “El Ostional” beach, located in the northern Ecuadorian Pacific coast have been presented. The samples were collected from six points over the shore area of approximately 500 × 40 m2. The data on crystalline phases (iron titanium oxide, orthoclase feldspar and zircon) were determined by X-ray powder diffraction (XRPD), while semi-quantitative chemical analyses of major (Fe and Ti) and trace elements were obtained by X-ray fluorescence spectroscopy (XRF). The phase composition was verified by scanning electron microscopy (SEM), using backscattered electron (BSE) mode and energy dispersive spectroscopy (EDS). These comprehensive data are a contribution to valorize ilmenite-hematite solid solutions from natural resources towards the identification of novel technological applications.

Diet composition and feeding habits of the pelagic thresher shark Alopias pelagicus in Eastern Central Pacific Ocean, Ecuadorian waters

AbstractThe diet and feeding habits of the pelagic thresher shark Alopias pelagicus were analysed based on 104 stomachs (N = 84 females, 20 males) collected off Santa Rosa de Salinas, in the Ecuadorian Pacific. The sharks were caught between February 2008 and January 2009 in artisanal fisheries. The trophic spectrum of A. pelagicus included 19 prey items (10 cephalopods and 9 teleost fishes), the main four prey were the red flying squid Ommastrephes bartramii, jumbo squid Dosidicus gigas, the purpleback flying squid Sthenoteuthis oualaniensis and the South Pacific hake Merluccius gayi. The trophic niche was narrow (Bi = 0.2), thus the pelagic thresher could be considered a specialist predator. The analysis of dietary overlap showed high similarity between the diets of females and males (Cλ = 0.99), immature and mature females (Cλ = 0.81), immature and mature males (Cλ = 0.72), sizes of 141–230 cm TL and 231–321 cm TL (Cλ = 0.97), as well as sharks in rainy season and dry season (Cλ = 0.77). Using canonical of correspondence analysis (CCA), we found similarities in the diet for all categories recorded (sex: canonical r = 0.38, P = 0.97; sexual maturity stage: canonical r = 0.54, P = 0.31; sizes: canonical r = 0.55, P = 0.26; seasons of the year: canonical r = 0.61, P = 0.75). The trophic level estimated for A. pelagicus was 5.0, which is typical of top predators (quaternary consumers or tertiary carnivores).

An integrative description of a new tardigrade species Mesobiotus romani sp. nov. (Macrobiotidae: harmsworthi group) from the Ecuadorian Pacific coast.

In a mixed moss and lichen sample collected in Esmeraldas Province in north-western Ecuador, 20 tardigrades and 11 eggs, belonging to a new species of the genus Mesobiotus, were found. In addition to the traditional taxonomic description with morphometrics, light and scanning microscopy imaging, we also provide nucleotide sequences of three nuclear (18S rRNA, 28S rRNA, ITS-2) and one mitochondrial (COI) DNA fragments of the new species. Based on the egg chorion morphology, Mesobiotus romani sp. nov. is the most similar to: M. binieki, M. coronatus, M. dimentmani, M. patiens, M. perfidus, M. philippinicusi, M. pseudoblocki, M. pseudocoronatus, M. pseudopatiens, M. radiatus, M. rigidus, M. simulans and M. wuzhishanensis, but differs mainly by some specific characters of both egg and adult morphology, and morphometrics.