Background. The genus Potamocoris (Hemiptera: Potamocoridae) is characterized by its Neotropical distribution and specialization in headwater aquatic environments, with records in Mexico limited to a single locality in Veracruz. Goals. This study aims to expand knowledge of the genus's geographic and altitudinal distribution in the country by providing new records from the Jalisco Coast region. Methods. During 2024 and 2025, surveys were conducted at nine sites in the Cuitzmala and Purificaci & oacute;n basins, which are designated as national water reserves. A 500 & micro;m D-frame net was used to collect aquatic insects, preserved in 80 % ethanol, and identified using stereomicroscopy and scanning electron microscopy. The ICAYAR multimetric index was applied, and physicochemical parameters were measured to assess ecological quality. Results. Nine individuals of Potamocoris were collected at two headwater sites: La Eca (522 m a.s.l.) in the Cuitzmala basin and Puente Caba & ntilde;as (543 m a.s.l.) in the Purificaci & oacute;n basin. These records expand the genus's altitudinal and geographic distributions in Mexico, evidencing its presence in freshwater systems along the Pacific coast. The sites showed ecological quality rated as "Good," with one site rated as "Acceptable," with temperatures of 20.5-27.6 degrees C, slightly alkaline pH, and low turbidity. Conclusions. The repeated presence of Potamocoris in perennial headwater rivers reinforces its association with well-conserved environments and highlights the value of water reserves as refuges for aquatic biodiversity. This new record contributes to the natural history of the genus and emphasizes the need to maintain integrated monitoring programs to strengthen conservation and management of water resources in Mexico.
Background. The cannonball jellyfish Stomolophus sp. (Scyphozoa: Rhizostomeae) typically inhabits marine coastal waters with oceanic salinities around 35%o and is usually associated with estuarine or nearshore environments under strong marine influence. Although sporadic incursions into brackish waters have been reported, occurrences in truly freshwater reaches are considered highly unlikely for scyphozoan jellyfish. Goals. Here we report an unprecedented occurrence of this species in the freshwater section (salinity = 0.199%o) of the Muleg & eacute; River, Baja California Sur, Mexico, and discuss its implications for osmotic tolerance, dispersal processes and habitat connectivity. Methods. On 17 June 2025, we observed a total of 22 individuals distributed along a short river segment, all of which showed signs of poor physiological condition (reduced bell turgor, discoloration and limited swimming activity) but were still clearly identifiable as Stomolophus sp. Results. Their presence in almost-freshwater conditions represents an exceptional case of passive upstream transportation, most likely driven by tidal dynamics and river flow, combined with a Short-term tolerance to extreme osmotic stress. This record expands the known environmental tolerance of Stomolophus sp., previously documented at minimum salinities of about 10%o, and suggests that short excursions into very low salinity habitats may occur more frequently than currently recognized. Conclusions. This report enhances current knowledge of the gelatinous fauna of the Gulf of California, highlights the ecological connectivity linking marine, estuarine and riverine environments, and provides a solid baseline for future experimental and field studies on how jellyfish cope with rapid salinity changes and other forms of environmental stress.
Background. The constant degradation faced by coral reefs has resulted in marked reductions in coral populations and a progressive loss of reef functionality, which in turn has driven an increase in restoration strategies aimed at compensating for these losses. Although asexual reproduction of corals has been the most popular technique in restoration, the importance of genetic diversity has led to an increase in the use of sexual reproduction. Even though the fact that records of coral spawning are key for the establishment of these strategies, there is very little information at regional and local scales about these events. Goals. Here we document two male Montastraea cavernosa colonies releasing gametes. Methods. The observations were made accidentally while technical and recreational diving activities were being conducted. Results. The first spawning event was recorded on 10 August 2020 (seventh day after the full moon, 96 minutes after sunset), consistent with previous reports. However, the second event was observed on 28 May 2024 (fifth day after the full moon, 29 minutes after sunset) approximately three months earlier than the earliest report. Conclusions. This second observation constitutes the only record of spawning in May for the species; however, because it is an isolated opportunistic record, it is more prudent to regard it as an atypical or desynchronized event.
Background. Monitoring threatened species with low population densities in tropical aquatic ecosystems presents significant methodological challenges, particularly for elusive and cryptic organisms such as the manatee (Trichechus manatus manatus). Environmental DNA (eDNA) has emerged as a promising non-invasive tool; however, its efficiency may be strongly affected by complex environmental matrices such as turbid waters and inhibitor-rich sediments. Goals. To evaluate the effectiveness of eDNA for detecting manatee presence in tropical aquatic systems of the southern Gulf of Mexico and to compare different extraction methods for water and sediment samples. Methods. Water and sediment samples were collected from four sites in Tabasco, Mexico. Two extraction methods were compared for water samples (phenol-chloroform and QIAGEN DNeasy Blood & Tissue commercial kit) and three for sediments (Chelex, chloroform-isoamyl alcohol, and CTAB). Detection was performed via quantitative real-time PCR (qPCR) using primers for manatees. DNA concentrations and amplification success were statistically analyzed in R software. Results. For water samples, both extraction methods yielded quantifiable DNA and amplification success rates above 90%, with no significant differences between them (p > 0.05). In sediments, although Chelex and chloroform methods produced higher DNA concentrations, the CTAB protocol showed a significantly higher proportion of positive amplifications (87.5%, p < 0.001), indicating effective removal of PCR inhibitors. Conclusions. eDNA analysis confirms its applicability for detecting manatees in challenging tropical environments; however, the environmental matrix strongly influences methodological performance. Water samples are more reliable for routine monitoring, while CTAB is strongly recommended for sediment samples due to its superior amplification success.
Background: This study assesses the impact of the policies implemented by Mexico between 2008 and 2024 to protect the vaquita, on small-scale fisheries operating in the Upper Gulf of California. Methods: Using production and operational data derived from landing reports for the shrimp, croaker, and mackerel fisheries in: San Felipe, Baja California; as well as Golfo de Santa Clara and Puerto Pe & ntilde;asco, Sonora, the analysis compares four periods: pre-intervention (2000-2007), implementation of the PACE-Vaquita program (2008-2014), the two-year fishing closure (2015-2017), and the subsequent prohibition of gillnets (2017-2024). Results: The results show that the conservation measures did not achieve sustained reductions in fishing effort or in gillnets use. Discussion: During the PACE-Vaquita, despite investments in technological conversion and vessel retirement, landings and operational indicators increased across all fisheries. The 2015-2017 closure led to temporary declines, but fishing activity rebounded rapidly once compensatory payments ended, surpassing pre-intervention levels-even after the prohibition on gillnets. These trends are associated with the continued operation of highly efficient vessels, the reinvestment of subsidies into fishing activities, the issuance of new permits, and the widespread and persistent use of illegal gillnets, as documented by national and international monitoring bodies. By 2024, the three fisheries had expanded substantially, intensifying pressure on the vaquita population. Conclusions: The findings demonstrate that nearly two decades of conservation efforts have not reversed the species' decline nor curbed fishing intensity, highlighting structural socioeconomic constraints and weak enforcement as key challenges to the species' recovery.
