a) Estructura del hectocotilo (Hct) en pulpos machos, detalles de...

Environmental and Anthropogenic Influences on Coliform Concentrations in the Octopus insularis Production Chain in the Veracruz Reef System, Gulf of Mexico

Article

Full-text available

Sep 2023

Simple Summary The contamination of coastal waters, unhealthy conditions and inadequate handling practices tend to reduce the sanitary quality of fishery products, thus impacting its marketing. With this in mind, we investigate the microbiological quality of the Octopus insularis in each stage of the production chain, comprehending capture, post-capture, processing and commercialization, in terms of the presence of total and fecal coliforms at the Veracruz Reef System, Gulf of Mexico. The environmental and anthropogenic influence on the space–temporal concentration of coliforms were analyzed in sea water, fresh octopus, fresh water, ice and octopus, both packed in ice and boiled. Most relevant results indicated that coliforms are present in the octopus production chain, being highest in the marketing stage. The coliform concentration increased during the rainy season and was highest in the reefs closer to the coast, which has a major anthropogenic influence. These results point out the urgent need to implement an efficient cold chain with adequate handling practices to try to reverse these microbiological conditions and improve the octopus quality and food safety. Abstract Coliforms are relatively common in aquatic environments, but their concentrations can be increased by environmental changes and anthropogenic activities, thus impacting fisheries resources. To determine the microbiological quality in the octopus production chain (capture, post-capture, processing and commercialization), total (TC) and fecal (FC) coliforms were quantified in sea water, fresh octopus, fresh water, ice and octopus in two presentations: packed in ice and boiled. Samples came from fishing zones Enmedio, Chopa and La Gallega at the Veracruz Reef System (VRS) during dry, rainy and windy seasons. The coliforms were determined using the most probable number technique (MPN). The most relevant results indicated that octopus packed in ice coming from the commercialization stage had FC levels >540 MPN/100 g, which exceeded the permissible limits (230 MPN/100 g). Therefore, these products present a risk for human consumption. Differences in FC were observed in octopuses between the three fishing zones (H = 8.697; p = 0.0129) and among the three climatic seasons, increasing during the rainy season, highlighting La Gallega with 203.33 ± 63 MPN (H = 7.200; p = 0.0273). The results provide evidence of the environmental and anthropogenic influences on coliform concentrations and the urgent need to implement an efficient cold chain throughout octopus production stages with adequate handling practices to reverse this situation.

Hacia la comprensión de los aspectos sociales y económicos de la pesca en el Corredor Arrecifal Veracruzano: Tamiahua como caso de estudio

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Oct 2019

Sistema Arrecifal Lobos-Tuxpan is immersed in a fishing area spanning from Tamiahua to Cazones. The knowledge of the fishing activity on the area, specially the one that addressing social aspects of fishing communities has not been explored. For this reason, using surveys and data from CONAPESCA, we analyzed the socio-economic (cost-benefit) context as well as the specific composition of the marine fisheries in 2008. Fishing activities on the area are artisanal with around 300 fishermen with basic study level (primary) and low monthly income ($90.9 USD). Classifying and ordering analyses suggest a temporary structure of target species (September to January and February to August) characterized by fluctuating catch volumes and commercial value which together maintain the profitability of the fishing fleet with a revenue of $70,611.89 USD on 2008 divided between concessionaires and cooperatives.

POPULATION ANALYSIS OF SNAPPER LUTJANUS GRISEUS, THROUGH THE ARTISANAL FISHERY ON THE COAST OF TAMIAHUA, VERACRUZ

Article

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Feb 2019

Artisanal fishery in the Gulf of Mexico is mainly undertaken for subsistence and is, thus, of great socioeconomic importance, with Lutjanidae one of the most important families caught in the region. However, there is scarce fisheries knowledge in the Gulf of Mexico and, in light of pressure from the fishing community, research into the population dynamics of these species is of vital importance for the management or conservation of coastal resources. This study aims to contribute information for the analysis of the population of Lutjanus griseus (Linnaeus, 1758), a common species on the Tamiahua coast, in the state of Veracruz. Samples and biometric data (weight, sex, total length and maturity) were recorded by the fishing community on this coast. The monthly population structure was constructed using fish size. Data from 987 individuals, the size of which oscillated from 15 to 80 cm, were registered over the course of a year. The sex ratio was 1:1, while the maximum calculated age was 10 years. Von Bertalanffy and Gompertz growth models reported a maximum age and growth of L∞=182.46 K= 0.05 and to = -1.71. The best fit was achieved by means of the Gompertz model, as based on the Akaike criteria and the biological interpretation of the parameters. Reported data and the models used in this study suggest that the minimum catch size should be 40 cm and that the fishery should either cease activities in the months of the reproductive peak or that quotas should be among the fishing cooperatives on the coast of Tamiahua.

An integrative taxonomic approach reveals Octopus insularis as the dominant species in the Veracruz Reef System (southwestern Gulf of Mexico)

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Dec 2018

The common octopus of the Veracruz Reef System (VRS, southwestern Gulf of Mexico) has historically been considered as Octopus vulgaris, and yet, to date, no study including both morphological and genetic data has tested that assumption. To assess this matter, 52 octopuses were sampled in different reefs within the VRS to determine the taxonomic identity of this commercially valuable species using an integrative taxonomic approach through both morphological and genetic analyses. Morphological and genetic data confirmed that the common octopus of the VRS is not O. vulgaris and determined that it is, in fact, the recently described O. insularis. Morphological measurements, counts, indices, and other characteristics such as specific colour patterns, closely matched what had been reported for O. insularis in Brazil. In addition, sequences from cytochrome oxidase I (COI) and 16S ribosomal RNA (r16S) mitochondrial genes confirmed that the common octopus from the VRS is in the same highly supported clade as O. insularis from Brazil. Genetic distances of both mitochondrial genes as well as of cytochrome oxidase subunit III (COIII) and novel nuclear rhodopsin sequences for the species, also confirmed this finding (0-0.8%). We discuss our findings in the light of the recent reports of octopus species misidentifications involving the members of the 'O. vulgaris species complex' and underscore the need for more morphological studies regarding this group to properly address the management of these commercially valuable and similar taxa.

Depredation by coastal bottlenose dolphins (Tursiops truncatus) in the southwestern Gulf of Mexico in relation to fishing techniques

Article

Nov 2018

Cetacean-fisheries interactions are a recurring problem. These interactions are conflict prone, especially between fishers and those seeking marine mammal conservation. In the southwestern Gulf of Mexico, a large fleet of artisanal fisheries operates using a range of different techniques. We recorded 90 fishing operations in two different fishing areas of Veracruz, Mexico, between 2009-2010 and 2014-2015, assessing whether dolphin interaction negatively affects fish catch and fish gear. These potential impacts were evaluated using three generalized linear models (GLMs) hypothesizing that (1) depredation decreases catch per unit effort (CPUE), (2) the predator presence modifies catch composition, and (3) prey species presence increases the likelihood of depredation. Of the gillnet hauls analyzed, 27 were subject to depredation by bottlenose dolphins, despite conditions and fishing methods varying among sites. Higher CPUE attracts larger pods, but a negative effect by depredation was not detected. We also found that depredation probability increased when there were higher capture volumes, when mackerels and jacks were present, and when operations were most southwesterly. Despite the short distance (< 80 km) between sites, we found that bottlenose dolphins on each site displayed different feeding behaviors towards fishing nets. Regarding conservation, bycatch caused by dolphins does not seem to be problematic. In fact, the increase in boat traffic and declining prey abundances due to overfishing could be the main causes of fishers' economic loss. Dolphin-fisheries interactions may not represent an actual challenge for marine conservation managers, but stakeholders, fisheries, and governmental institutions should be aware that diminishing returns due to overfishing could exacerbate the apparently false notion of dolphins competing for the fish.

Model uncertainty and Bayesian estimation of growth parameters of Yellowtail Snapper (Ocyurus chrysurus) from Veracruz, Mexico

Article

Full-text available

Aug 2018
HIDROBIOLOGICA

Background. Most growth analyses of Yellowtail Snapper neglect consideration of model and parameter uncertainty. Goals. In this paper, we explore model uncertainty using three models (von Bertalanffy, logistic, and Gompertz) as well as the Akaike criterion for model selection. We also estimate growth parameters and its uncertainty using the maximum likelihood estimation approach (under different assumptions of error variance) and Bayesian methods. Methods. Models were fitted to length-at-age data from organisms caught in Antón Lizardo, Veracruz. Regarding the Bayesian methods, a prior distribution for the asymptotic length was built based on data gathered from literature. We used Monte Carlo Markov Chains (MCMC) methods to fit the logistic model. Results. The Akaike criterion results suggest that the logistic model provided the best fit for the observed data (lowest AIC = 31.4). Parameter estimates included asymptotic length (L∞ = 64.9 ± 5.43), growth rate (K = 0.49 ± 0.07), and age at the curve inflection point (I = 3.28 ± 0.42). Regarding the Bayesian analysis, MCMC simulations suggest that the most probable value for the asymptotic length was 64.3 cm with an interval of 95% probability (58.7, 70.1). The most probable value for the growth rate was 0.48 with an interval of 95% probability (0.42, 0.55). Last, the most probable value for the age at the curve inflection point was 1.7 years with a range of 95% probability (1.31, 2.16). Conclusions. The maximum likelihood estimation (MLE) and the Bayesian framework should be considered basic statistical techniques in the evaluation of individual growth of the species of interest, as they provide a robust analysis of available information of the species and the opportunity to incorporate such analysis to sustainable management practices. © 2018 Universidad Autonoma Metropolitana. All rights reserved.

Model uncertainty and Bayesian estimation of growth parameters of Yellowtail Snapper (Ocyurus chrysurus) from Veracruz, Mexico

Article

Full-text available

Aug 2018
HIDROBIOLOGICA

Jesús Jurado Molina

Background: Most growth analyses of Yellowtail Snapper neglect consideration of model and parameter uncertainty. Goals: In this paper, we explore model uncertainty using three models (von Bertalanffy, logistic, and Gompertz) as well as the Akaike criterion for model selection. We also estimate growth parameters and its uncertainty using the maximum likelihood estimation approach (under different assumptions of error variance) and Bayesian methods. Methods: Models were fitted to length-at-age data from organisms caught in Antón Lizardo, Veracruz. Regarding the Bayesian methods, a prior distribution for the asymptotic length was built based on data gathered from literature. We used Monte Carlo Markov Chains (MCMC) methods to fit the logistic model. Results: The Akaike criterion results suggest that the logistic model provided the best fit for the observed data (lowest AIC = 31.4). Parameter estimates included asymptotic length (L∞ = 64.9 ± 5.43), growth rate (K = 0.49 ± 0.07), and age at the curve inflection point (I = 3.28 ± 0.42). Regarding the Bayesian analysis, MCMC simulations suggest that the most probable value for the asymptotic length was 64.3 cm with an interval of 95% probability (58.7,70.1). The most probable value for the growth rate was 0.48 with an interval of 95% probability (0.42, 0.55). Last, the most probable value for the age at the curve inflection point was 1.7 years with a range of 95% probability (1.31, 2.16). Conclusions: The maximum likelihood estimation (MLE) and the Bayesian framework should be considered basic statistical techniques in the evaluation of individual growth of the species of interest, as they provide a robust analysis of available information of the species and the opportunity to incorporate such analysis to sustainable management practices.

COMPORTAMIENTO DE TURSIONES (Tursiops truncatus) EN LA INTERACCIÓN CON LA PESCA ARTESANAL EN LA COSTA CENTRAL DE VERACRUZ, MÉXICO

Thesis

Full-text available

Dec 2016

Nataly Morales-Rincon

relationship of organisms with their environment influences their behavioral plasticity, modifying their behavior in response to stimuli or pressures, and consequently affecting the ecological relations of species. The expansion of human activities leads to conflicts between humans and wildlife, and these are mainly associated with interactions during competition for space and / or food availability. These conflicting interactions have been reported on the shores of the Gulf of Mexico, where the artisanal fishermen denounce the looting and damage of their equipment by tursiones (Tursiops truncatus), which are sometimes injured or killed. The objective of this work was to study the behavior of bottlenose dolphins in their interaction with artisanal fishery in the coastal waters of Alvarado, establishing: 1) the first etogram for the case, 2) the behavioral differences associated with fishing, and 3) the variations in relation to the age and group size of the dolphins interacting with this activity. Between 2015 and 2016, 64 groups have been observed by sampling scanning from boats and fixed points. We obtained 4,898 records that used body patterns and other characteristics associated with the behavioral deployment form. The events were organized in the states: food, locomotion, social, socio-sexual, play and rubbing with objects. There were significant differences in the frequency (X2 = 55.93, gl = 5, p <0.001) and the local rate of behavior in the presence and absence of fishing activity (X2 = 25.16, gl = 5; However, their intensity was lower than in the absence of fishing (5.3 min-1 vs 7.0 min-1) and in relation to the other behaviors, that in general had low frequencies. During the fishing activity, the dolphins that interacted most were adults, however, no significant group differences were found in the proportion of individuals by age in relation to the fishery ( X2 = 1429, gl = 2, p <0.4894). The average group size comprised two individuals in both conditions (without = 42% and con = 54% interaction), so no differences were observed (X2 = 1.56, gl = 15, p <0.001); however, the direct operational interaction to the net was performed by 51% individually, and mostly (84%) in the first 30 m. The behavioral differences partially support the hypotheses and evidence the influence of human activities on the behavioral display of the T. truncatus dolphins in Alvarado. The lack of evidence on differences in age and group size suggest the need for a larger sample size, as well as the habituation of some dolphins to the fishery interaction, possibly being these experienced dolphins that will pass; these dolphins would have to be photo-identified to determine their contribution in the effects on the behavior of the population, derived from their interaction with the artisanal fishery.

Spatial distribution and ecological structure of Thalassia testudinum (Hydrocharitaceae) in two reefs of Veracruz Reef System National Park, Mexico

Article

Full-text available

Jun 2016
REV BIOL TROP

Seagrasses in coastal environments have been threatened by increased human activities; these have negatively altered processes and environmental services, and have decreased grassland areas. The aim of this study was to generate knowledge of Thalassia testudinum distribution, state of the structure and fragmentation level in two reefs of the Veracruz Reef System National Park (PNSAV). Two different reefs were selected: Sacrificios in the North and near the coast, and Cabezo in the South and away from the coast. Shoot-specific and area-specific characteristics of submerged macrophytes meadows present were determined, and four morpho-functional groups were identified. Significant differences between plant coverage were tested through nonparametric ANOVA, Kruskal-Wallis test. A supervised classification of spatial high-resolution image verified with field data was performed (55 Sacrificios and 290 Cabezo). The fragmentation level was calculated using landscape metrics, class level and thematic maps were made based on four covers. The meadows were dominated by Thalassia testudinum; maximum densities were 208 shoot/m2 in Cabezo, and 176 shoot/m2 in Sacrificios. Cabezo presented grasses with short (9 cm) and thin leaves (0.55 cm) on average; while Sacrificios showed longer (23.5 cm) and thicker (1 cm) leaves. Sacrificios showed lower fragmentation degree than Cabezo; in both cases, the vegetation cover fragmentation corresponded to less than 50 %. Although Cabezo reef presents further fragmentation, which creates a large number of microenvironments, being recognized for its importance as recruitment area. This work serves as a baseline for the creation of an adequate management plan (formation of a core area of Cabezo). It is necessary to complement this work with new efforts for the recognition of seagrass prairies in all PNSAV reefs, as well as periodic monitoring and recognition of ecosystem services. .

Vulnerabilidad de Comunidades Pesqueras Artesanales al Cambio de Uso de Suelo en la Zona de Influencia del Sistema Arrecifal Veracruzano, México

Thesis

Full-text available

Feb 2016

Ondrej Bazant Fabre

Historically, the Veracruz Reef-System (VRS) allowed the coastal settlement of a commercial port and fishing communities due to the protection and biodiversity it provides; the communities adjacent to the port became the city of Veracruz (VER) to the north, while others became the towns of Boca del Río (BDR) and Antón Lizardo (AL) southward. In the last half of the 20th century an accelerated urban growth, promoted by political development plans, has joined VER and BDR in a single metropolitan area and it seems it will reach AL in the near future. Furthermore, the VRS was decreed a marine park in 1992 and the expansion of the port was recently authorized, which will destroy a couple of reefs units in its northernmost portion and displace the fishing community of Playa Norte. The objective is to evaluate the vulnerability of these small-scale fishing communities under land-use exposure; the hypothesis is that vulnerability will decrease in a north-to-south gradient in function of land-use exposure. A twoway methodology was developed: i) vulnerability index, composed of criteria and indicators of sensitivity (11 indicators grouped in three criteria – ‘fishing activity’, ‘food security’ and ‘proximity to shore and access to the economic exclusive zone’) and adaptive capacity (14 indicators grouped in three criteria: ‘socioeconomic profile’, ‘opportunity cost’ and ‘local governance’), collected via weighted surveys; and ii) exposure index, composed of changes between four categories of land-use impact and generated via geographical information system analyses for the last four decades. Even though sensitivity was higher than adaptive capacity, the vulnerability of all three fishing communities was medium with slight differences between them (VER>AL>BDR). The coastal-marine exposure index remained in low levels due to the fact that most of the marine surface remains unchanged; by contrast, terrestrial exposure index achieved medium and high levels; in both cases, a north-south gradient was observed (VER>BDR>AL). The correlation between both indexes behaved linearly and, even though it wasn´t statistically significant, it suggests that exposure does indeed promote the vulnerability of smalle-scale fishing communities. The results shed evidence toward an inefficient governance of tenure, which in turn promote ocean grabbing processes by means of detrimental land-use change, all of which increment the sensitivity and mitigate the adaptive capacity of smalle-scale fishing communities in the VRS.

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