The mining port of Santa Rosalia presents elevated concentrations of potentially toxic elements (PTEs) in its sediments that exceed ecotoxicological standards, representing a risk to marine biota. In cephalopods, embryonic exposure to PTEs can induce morpho-physiological changes that jeopardize survival and, consequently, reproductive success. The octopus Octopus hubbsorum, resident in the Santa Rosalia region, shows a marked capacity for bioaccumulation of Cd, Mn, Ni, Pb, and Zn, suggesting the possibility of accumulation in embryos and even maternal transfer. The present study evaluated the incidence and type of embryonic abnormalities in O. hubbsorum originating from an area highly contaminated by PTEs. Three portions of egg masses (45 festoons in total) collected in Santa Rosalia were analyzed. Embryonic development was morphologically characterized by using a stereomicroscope and photographic records. To estimate the number of eggs per festoon, unfertilized eggs, and eggs with abnormalities, a 1-cm segment from each festoon was analyzed. The results revealed 3.7% abnormalities, corresponding to 10 types of alterations, classified as defects in the morphology of the yolk sac and embryo, with a higher prevalence of eggs with translucent embryos and yolks. The incidence of abnormalities was low compared with previous reports and suggests that they are related to natural or environmental causes. The egg masses presented 0.84% unfertilized eggs. Despite the high levels of PTEs in Santa Rosalia, the embryonic development of O. hubbsorum is not significantly affected, likely due to the short exposure time during embryonic development (3 to 4 weeks), the low bioavailability of PTEs in the water column, or the low permeability of the chorionic capsule. Nevertheless, additional studies are required to evaluate these mechanisms with greater precision.
A digital bathymetric model was generated for a specific area of the Punta Mita Shallow-Water Hydrothermal System, and the spatial distribution of some active hydrothermal vents was mapped. Bathymetric data acquired with a single-beam echosounder were interpolated at 2 m resolution, and vent locations were analyzed using spatial and kernel density methods. The results provide a first-order, continuous geomorphological approach of the seabed in this area, agreeing in certain aspects with the previously reported fault system, but also showing new lineaments, depressions, and morphological features associated with hydrothermal activity.
Mangrove ecosystems along the American continent represent vital habitats supporting diverse marine life, including elasmobranchs. This study comprehensively examines elasmobranch diversity and their utilization of neotropical mangrove habitats. Through an extensive review of literature, museum collections, and online databases, we compiled records of elasmobranch species inhabiting mangroves across 15 countries, encompassing 29 localities. The findings reveal a rich diversity of elasmobranchs, with 35 shark species representing eight families and four orders and 48 batomorph species from 13 families and four orders. Intriguingly, this diversity is unveiled despite the relatively limited attention that mangrove ecosystems and elasmobranchs have received in scientific research, especially compared to other marine environments. Except for charismatic species, much remains unknown about the utilization of mangrove habitats by various shark and ray species. The study highlights the crucial role of museum collections in verifying and enhancing our understanding of elasmobranch richness in these habitats. Furthermore, the research sheds light on the conservation status of these species, revealing that nearly half of the elasmobranchs cataloged in this study are currently listed as threatened, according to the IUCN Red List. This underscores the urgency of protecting mangrove habitats, which face significant degradation and loss due to human activities. We emphasize the importance of addressing gaps in our knowledge regarding the relationship between mangrove habitats and elasmobranchs and underscore the need for increased research and conservation efforts in these critical ecosystems. Ultimately, this research contributes to understanding the intricate connections between neotropical mangroves and elasmobranchs and highlights their significance in marine biodiversity conservation.
The development of Opistognathus rosenblatti from larvae to juveniles is described using 60 specimens (3.6-47.0 mm LP). Adults were captured in the Loreto Bay Marine Park, Gulf of California, Mexico. They were conditioned and bred in captivity. Changes from larva to juvenile in morphological, meristic, and pigmentation pattern characters were described from specimens preserved in formalin solution (4%). Meristic data of larvae and juveniles were 27-29 total myomeres, XI, 13 dorsal fin, II, 13 anal fin, 8+7-9 caudal fin, and 5 hypural bones. The pigmentation pattern of the larvae from preflexion to postflexion stage consisted of: A cephalic region with small melanophores on the dorsal surface of the brain, on the lower margin of the nasal capsule, on the lateral surface of the lower and upper jaws, on the nape, and the gular region; abdominal region with a series of melanophores on the intestinal sac margins, including the swim bladder; the trunk region with few melanophores in the last myomeres; caudal region with three series of stellate melanophores on the dorsal, ventral margins and medial-lateral section between myomeres 1-14. Other stellate melanophores were present throughout this section, which interlaced towards all margins, providing a very light brown coloration on this section of the body. The juvenile is yellow-orange, with small punctate melanophores that extend across its entire body surface. It also exhibits four discontinuous series of brown spots (circular to oval) extending from the ventral-posterior margin of the eye to the height of the tips of the bases of the dorsal and anal fins. The conjunction of pigmentation patterns, myomeres count, and fin meristics is a distinctive identifier for O. rosenblatti larvae and juveniles, as it is not observed in the larvae of other fish species.
Understanding population-level variation in thermal tolerance is essential for predicting species responses to climate change. This study assessed the lethal low and high temperatures (LT50) of juvenile Pacific lion-paw scallops (Nodipecten subnodosus) from two environmentally contrasting regions of the Baja California Peninsula: Laguna Ojo de Liebre (LOL, Pacific coast) and Bahía de Los Ángeles (BLA, Gulf of California). Individuals were exposed to a 96-h thermal bioassay across seven fixed temperatures (5–35°C) utilizing a precision-controlled marine simulation system. Mortality was recorded hourly, and LT50 values were estimated via Probit regression analysis. Both populations exhibited similar lower LT50 (~6.6°C), but significantly different upper LT50: 30.58°C for LOL and 32.13°C for BLA. Results are evidence of adaptive evolution differences. Comparison with historical environmental data indicate that BLA scallops, despite facing higher thermal stress, exhibit greater resilience, making them promising candidates for aquaculture under climate change scenarios. Future research may consider the LT50 values reported here as instrumental for projecting the climate change impacts and aquaculture planning.
The reproductive biology of the stone scorpionfish (Scorpaena mystes) was described by analyzing organisms caught by the artisanal fishing fleets that operate in the Gulf of California's west coast. Two hundred fifty-eight organisms (134 females, 115 males, and 9 undifferentiated) were collected from May 2015 to March 2016. Total length (TL) ranged from 19.5 to 44.5 cm for females and 16.6 to 35.5 cm for males. In the gonad histological analysis, 5 and 3 reproductive phases were observed for females and males, respectively; in addition, a period of reproductive inactivity was observed for both sexes. The estimated size at first maturity was 26.2 cm TL for females, 27.5 cm TL for males, and 27.2 cm TL for the general population. The results indicated that the reproductive period of the stone scorpionfish is short (from May to August), with reproductive synchronicity between females and males during July. The present study presents the necessary information for establishing management measures to regulate the capture of the stone scorpionfish, with a recommended minimum capture size of 26.2 cm TL and a fishing ban from May to August.
Egg sinking rates of the sympatric species Thysanoessa spinifera and Euphausia pacifica were investigated in the context of cross-shelf seawater conditions and vertical distributions of early ontogenetic stages (eggs, nauplii, calyptopes, and furciliae) along the Oregon coast during summer, 1977. The highest abundances of eggs, calyptopes and furciliae were near the surface (<30 m), and nauplii were in deeper layers (50–100 m), indicating that the eggs sank to <90 m depth and calyptopes migrated into shallower waters. Mean T. spinifera egg diameters were less (chorion 0.376; embryo 0.331 mm) than those of E. pacifica eggs (chorion 0.406; embryo 0.364 mm). Experimental mean egg sinking speeds of single cell stage eggs, measured at constant 11°C temperature, 33.436 salinity, and 25.686 sigma-t, were almost identical for T. spinifera (126 m d-1, range 60–193 m d-1) and E. pacifica (128 m d-1, range 103–175 m d-1). Instantaneous egg-sinking speeds calculated from the Navier-Stokes Law showed that egg densities of both species were always greater than the seawater density observed at Oregon coast. However, Navier-Stokes predicted egg sinking speeds were between 5–12 times faster than inferred from in situ vertical distributions of successive ontogenetic stages, theoretically suggesting that a proportion of the eggs may actually reach the sea floor. Upwelling, stratification, turbulence, horizontal currents and seafloor boundary layer effects do not explain the apparent egg sinking speed (<80 m d-1) inferred from egg and larvae distributions. However, a combination of them may. I infer that sinking of eggs and early ontogenetic daily migrations maintain most of the early stages close to the coast due to the predominant cross-shelf currents. Offshore transport near the sea surface and onshore transport in deeper layers keep the larvae over the continental shelf. Keywords: Navier-Stokes law, larval drift, ontogenetic segregation, Euphausia pacifica, Thysanoessa spinifera.
Shrimp aquaculture is a rapidly growing system globally, driven by accessible markets and burgeoning demand. In the Mexican context, whiteleg shrimp (Litopenaeus vannamei) is the main aquaculture organism. The objective of this study was to evaluate the feasibility and profitability of both a short-term harvest lasting nine weeks within a semi-intensive farm and a 26-week harvest conducted on the same farm during the same operational year. This study meticulously tracked biological and economic variables for both production schemes. The results revealed an average final shrimp weight of 8.09 g with a growth rate of 0.79 ± 0.56 g/week for the 9-week harvest and 26.7 g. with a growth rate of 1.03± 0.44 g/week for the 26-week harvest. The net revenue for the 9-week harvest reached 145,213.46 USD, with a benefit-cost ratio of 2.07, whereas the net revenue for the 26-week harvest reached 1,361,415.86 USD, with a benefit-cost ratio of 2.62. As a negative forecast, the 9-week harvest risk analysis indicated a high certainty of exceeding limit reference points (LRP) for growth, survival, and biomass. In contrast, target reference points (TRP) showed a certainty of 0% to be exceeded. While the economic analysis showcased a favorable benefit-cost ratio, the study underscores the vulnerability of semi-intensive systems to physicochemical impacts, necessitating dynamic economic tools for profitability assessments. An analysis of state-of-the-art was carried out to search for simple, low-cost strategies and proposals to improve the efficiency of crops in low-tech, semi-intensive systems. The findings emphasize research avenues for improvement, particularly in optimizing larval quality validation, water quality, and feed strategies, and exploring innovative approaches like natural immunostimulants to enhance survival rates and overall net revenue in semi-intensive shrimp farming in northwestern Mexico.
Los organismos acuáticos son susceptibles de sufrir estrés cuando las condiciones ecológicas no son las adecuadas. La temperatura del agua es un parámetro de gran importancia debido a que afecta a las reacciones bioquímicas y fisiológicas en los organismos acuáticos. Asimismo, influye considerablemente en la concentración de oxígeno disuelto, por lo que resulta necesario evaluar y supervisar este parámetro. En este trabajo, se presenta un modelo computacional para la evaluación de la temperatura del agua en estanques de cultivo intensivo de camarón blanco Litopenaeus vannamei, mediante el estudio de 3 factores fundamentales: la temperatura promedio, la variación de amplitud y la duración de los cambios de temperatura. Mediante un sistema de razonamiento difuso, de evalúa cada factor por medio de reglas establecidas, obteniendo un indicador del impacto de la temperatura sobre el hábitat del camarón en cultivo. Los resultados se compararon contra los índices de calidad del agua de la U.S. National Sanitation Foundation (NSF) y de la Canadian Council of Minister of Environment (CCME), los índices más comúnmente usados. Se muestra un mejor comportamiento en la evaluación diurna de la temperatura, la cual penaliza de una manera más adecuada los cambios abruptos de temperatura, lo cual no es considerado por los otros índices.
Algae are exposed to substantial stress. In response, these organisms have developed efficient defense systems, such as protective secondary metabolite synthesis, making algae a primary source of bioactive compounds with a wide spectrum of biological activities. Thus, algae show potential for use in treatments of thrombotic, infectious, and chronic degenerative diseases. Therefore, the objective of this study was to evaluate the phytochemical compounds and pharmacological activity of an extract obtained from Sargassum lapazeanum. Algae were collected in the intertidal zone of Tarabillas beach (Bahía de La Paz, BCS). The biological activities of an ethanolic extract and its fractions were evaluated using chromatographic techniques. In addition, a bioautographic assay of hemolytic activity was conducted, and phytochemical profiles and acute toxicity in Artemia franciscana were evaluated. The relationships among the main extract components were also determined. The ethanolic extract exhibited significant antioxidant and hemolytic activity, which was mainly attributed to its content of anthrones, anthraquinones, and unsaturated triterpenes. Its toxicological activity reached an LC50 value of 225.1 μg mL-1, which was mainly attributed to alkaloids, flavonoids, anthrones, and saponins. The results suggest that Sargassum lapazeanum, which is endemic to the Gulf of California, has great pharmacological potential with biomedical applications.
Microalgae are a crucial factor in aquaculture activities, since they are used as live food in the larvae stage of shrimp, mollusks, and fish. Nevertheless, just a few microalga species are produce. In this study we evaluate the effect of salinity at 25, 35, 45 and 55 practical salinity unit (psu), in F/2 media as control group and two nitrogen (NaNO3) limited media, F/4 and F/8 on the diatom Thalassiosira weissflogii. To value the development of the diatom, kinetic growth curves, pH, biomass production and chemical-proximate composition were estimated. The highest growth rate and organic matter values were in media F/4 and 35 psu. Meanwhile, media F/8 at 55 psu presented the highest amount of ash and a very low growth rate. T. weissflogii is affected by high salinity concentration, however the limitation of nitrogen with 25 and 35 psu did not affect growth considerably. Concerning the chemical-proximate composition of T. weissflogii, media F/4 at 25 psu, presented the highest percentages of carbohydrates and proteins. In the same way, medium F2 at 25 psu, reported the highest amounts of carotenes. The results showed that high salinity was the variable that major affected the cell density, biomass production and chemical-proximate composition of T. weissflogii.
Management procedures (MP) were evaluated to address alternative management of the pink abalone (Haliotis corrugata) fishery in the Mexican Pacific. This assessment utilized the Method Evaluation and Risk Assessment (MERA) platform within the context of management strategy evaluation (MSE). This species has been a crucial component of the abalone fishery in Mexico, with a history dating back to the 19th century. Since 1996, fishery authorities and fishermen have noted a decline in the stock biomass. In response, they implemented various strategies and efforts to address the situation. However, despite these measures, the stock has yet to recover satisfactorily. Eight MP were evaluated, and two corresponded to the status quo (current catch and effort). The simulation results suggest that relying solely on effort-based MP falls short of meeting the management objectives set in the reference points (Biomass and Yield). In contrast, alternative strategies involving different quota allocation strategies (e.g., based on the depletion level) demonstrated superior performance and a higher likelihood of meeting management objectives. Despite incorporating fishery information, the existing management procedures could have performed better in the simulation. Therefore, it is crucial to assess and implement alternative management strategies that are more likely to succeed
Las llamadas "mareas rojas" o floraciones de fitoplancton se caracterizan por un aumento exponencial de la abundancia de una o varias especies. Se ha reportado que su ocurrencia puede estar asociada a eventos naturales y antropogénicos, por lo que se ha observado un incremento global en las últimas décadas. De acuerdo a su impacto en el ecosistema, estos fenómenos han sido clasificados como tóxicos o nocivos. El presente trabajo es resultado de una investigación sustentada en los análisis de muestras recolectadas el 12 de abril de 2018, en la región sur del Parque Nacional Loreto, BCS. En cuanto a la composición específica de las muestras, se determinaron nueve taxones pertenecientes a la fracción microfitoplanctónica (siete diatomeas, un dinoflagelado, un ciliado) con una abundancia total de 264,600 cells. L-l, con una concentración de 40.79 mg m-3 de clorofila a, y una productividad primaria equivalente a 80.5 mg C m-3 h-1. Las abundancias registradas para las diferentes especies, dan evidencia clara de una proliferación monoespecífica del ciliado Myronecta rubra el cual presentó una abundancia máxima de 256,600 cells. L-1 la cual representa más de 96% de la abundancia total del microfitoplancton. Palabras clave. - Proliferación, productividad primaria, clorofila a.
Fulton’s condition factor (k) and the length-weight relationship (LWR) are the most important biological tools with respect to basic aspects of fish population dynamics; they are applicable to strategic plans for the conservation and management of fisheries. A total of 478 snappers Lutjanus peru and L. guttatus were analyzed in Santa Rosalía, Baja California Sur, in the Gulf of California. The total length of Lutjanus peru ranged from 21 to 55 cm, and weight ranged from 215 to 1,920 g, whereas total length of L. guttatus ranged from 21 to 59 cm, and weight ranged from 290 to 1,675 g. The LWR and condition factor were estimated for the two species and intraspecific factors were analyzed (sex, season, maturity stage) using Bayesian hierarchical models with random effects. The parameters of the LWR equation were similar for the two snapper species (α≈0.026 and β ≈ 2.8); they both presented negative allometric growth (p(β<3)>85%). The L. peru growth rate was greater in the warm season (p(βwarm>βcold)≈97%), whereas this difference was not as evident in L. guttatus (p(βwarm<βcold)≈72%). The condition factor k was greater than 1 for all categories in the two species (p(μk)=100%), which suggests that they keep a good body condition. This indicates that L. peru and L. guttatus in Santa Rosalía experience environmental conditions that benefit their body condition, as a function of year-round food availability. This information is useful for future conservation studies and for monitoring snapper captures, as most L. peru individuals caught were sexually immature.
El Dr. Héctor Mayagoitia Domínguez, fue un científico y académico con una formidable trayectoria en la administración pública nacional. Durante su vida profesional, impulsó una incansable labor para favorecer que la formación tecnológica en México se configurase como una de las principales estrategias para contribuir a contrarrestar las diversas causas del deterioro ambiental; en particular, las manifestaciones del calentamiento global, lo cual fue a lo largo de su larga y prolífica vida profesional, objeto de una continua labor de investigación, de divulgación y de gestión al frente de los diversos ámbitos de su desempeño, culminando su labor dando vida a la Coordinación Politécnica para la Sustentabilidad.
El marisqueo es una actividad tradicional. La mayor parte del trabajo se efectúa con métodos de producción elementales en los bancos de arena de las zonas inter-mareales a tiempo parcial. Fue una actividad de subsistencia realizada, fundamentalmente y durante años, por mujeres. Los productos extraídos poseían una demanda reducida y su valor en el mercado era escaso. Desde mediados del siglo XX las administraciones públicas dictan medidas de ordenación a fin de regular y evitar la sobre-explotación de las áreas marisqueras. El marisqueo constituye en la actualidad la principal fuente de riqueza de las personas que la realizan. Las mujeres han sido claves en la demanda de profesionalización, reforzando el empoderamiento y la participación activa en la toma de decisiones. Más dicho proceso está conllevando, paralelamente, una tendencia hacia la masculinización. Se analiza el papel de las mujeres mariscadoras desde el enfoque económico y ambiental, vinculando su trabajo con los Objetivos de Desarrollo Sostenible; dando cuenta de los compromisos y tareas relacionadas con el mismo. Los resultados obtenidos prueban que las mariscadoras cumplen con la mayoría de ellos, asumiendo los principios de sostenibilidad y responsabilidad.
A diferencia de los taxones superiores, las especies no requieren ser monofiléticas; por debajo de ese nivel no hay taxones, sino poblaciones e individuos, con relaciones no filogenéticas, sino tocogenéticas. La existencia de “paraespecies”, especies no originadas a partir de una única población, es previsible, sobre todo cuando la especiación ha sido de tipo peripátrico, con una población periférica que diverge rápidamente (por ejemplo, debido a una regresión marina que la deja aislada en un embalse epicontinental) y deja en situación parafilética al resto de poblaciones de la distribución original. El concepto evolutivo de especie, i.e. la especie como linaje, no necesariamente excluye a las paraespecies. El criterio de independencia y coherencia evolutiva puede cumplirse mediante una diagnosis consistente, en especial si proviene de un enfoque taxonómico integrativo, con datos moleculares, ecológicos, biogeográficos y morfológicos.
Los manglares son ecosistemas altamente productivos y esenciales para numerosas especies. Sin embargo, han sufrido importantes pérdidas debido a la ocupación de espacios con fines industriales, tales como la acuicultura y agricultura. El objetivo fue determinar si la variación en la forma de la concha de Anadara tuberculosa está relacionada con la concentración de Cd y Pb en el tejido blando. Se recolectaron ejemplares en tres localidades de manglar del Ecuador continental. La localidad Esmeraldas se utilizó como sitio control debido a su bajo índice de contaminación en contraste con los sitios Guayas y El Oro, dos provincias con antecedentes de contaminación por metales pesados. Utilizamos coordenadas cartesianas y métodos de morfometría geométrica para analizar la variación y variabilidad de la forma de la valva derecha de A. tuberculosa. El análisis de variables canónicas indicó diferencias significativas entre las tres localidades, con la máxima variación de la forma ubicada en la porción derecha de la concha. Las concentraciónes de Cd y Pb en tejido no superaron el límite máximo permitido, sin embargo, Guayas registró la mayor concentración de Cd, acercándose al límite. En términos de variabilidad Esmeraldas presentó el mayor valor de disparidad morfológica. Sin embargo, las comparaciones pareadas de los valores de disparidad del sitio control con respecto a las localidades con altos índices de Cd no fueron significativas. Esmeraldas mostró la forma más disímbola en términos de disparidad parcial. Estos resultados indican la posibilidad de que la concentración de metales pesados produce variación en la forma de la valva de A. tuberculosa que es útil para distinguir entre los sitios de estudio. Los resultados enfatizan la necesidad de vigilar los niveles de Cd en las poblaciones de A. tuberculosa en las provincias de Guayas y El Oro con el propósito de conservar el ecosistema de manglar.
El nitrógeno es un nutriente esencial y limitante para los productores primarios marinos, bajo un delicado balance en ambientes oligotróficos i.e. Caribe mexicano. El desarrollo turístico y urbano del Caribe mexicano y, ahora, las arribazones masivas de sargazo pelágico, se identifican como fuentes nitrógeno que pueden alterar las condiciones oligotróficas de las lagunas arrecifales del Caribe mexicano. El objetivo del presente trabajo fue cuantificar el contenido de nitrógeno elemental en las hojas del pasto de tortuga Thalassia testudinum bajo un escenario de diversas fuentes de nitrógeno para determinar la posible contribución de estas fuentes al pasto de tortuga en el periodo de 1991 a 2019 en Puerto Morelos, Quintana Roo. El contenido promedio de nitrógeno fue 1.84±0.22% con mínimo de 1.71% y máximo de 2.20%. Este valor fue muy similar al intervalo establecido para otras lagunas costeras donde está presente este pasto marino. En el periodo de 1991 a 2019, las hojas de T. testudinum no mostraron evidencia de enriquecimiento de nitrógeno, excepto para el periodo de 2014 a 2016, bajo un escenario de arribazón de sargazo pelágico o por intenso pastoreo de las tortugas marinas. El contenido de nitrógeno estuvo en el límite de nitrógeno para su crecimiento, durante la arribazón masiva de sargazo del 2018 al 2019, lo cual supone estrés para el pasto marino bajo una mala calidad del ambiente marino.
