Taxonomic Notes
This species has been confused with Gobiosoma spes (Ginsburg 1944).
Justification
This shallow brackish water species has a restricted range in Lake Maracaibo, Venezuela. The estimated extent of occurrence (EOO) is 16,467 km² and the estimated area of occupancy (AOO) is 564 km². The environments that this species is dependent on in Lake Maracaibo are severely impacted by extensive and increasing activity by the oil and gas industry that has caused oil spills and natural gas leaks and fish kills and population declines have been observed. In addition, sewage runoff and other pollutants are uncontrolled and further impacts the lake waters. Based on this pervasive threat, the number of locations is one. It is listed as Vulnerable (VU B1+B2ab(iii)). Research is needed on the population status of this species.
Geographic Range Information
This species is endemic to Lake Maracaibo, Venezuela where it occurs throughout the fringe areas, but not in the middle of the lake (Van Tassell 2011, Robertson and Van Tassell 2023). It may also occur slightly outside the mouth of Lake Maracaibo in the Gulf of Venezuela but surveys conducted in that area did not catch this species (J. Van Tassell pers. comm. 2024). The depth range for this fish is 0–2 m (Robertson and Van Tassell 2023).
Based on a minimum convex polygon drawn around the extent of Lake Maracaibo, the estimated extent of occurrence (EOO) is 16,467 km². Based on overlaying a 2x2 km grid on the fringes of Lake Maracaibo, the estimated area of occupancy (AOO) is 564 km². The number of locations is one based on the pervasive impacts from oil and gas development throughout Lake Maracaibo.
Population Information
This species was commonly captured during a rotenone survey conducted in 2007 and nothing is known or has been updated since then, so its current abundance is unknown. In 2007, the environment was heavily impacted already and has progressively worsened since then. The population is not severely fragmented (L. Tornabene, D.R. Robertson, O. Domínguez, and J. Van Tassell pers. comm. 2024). It is known from at least 60 museum specimens collected in 1942 and 1978 (Ginsburg 1944, FishNet2 online database accessed October 2023).
Habitat and Ecology Information
This benthic species inhabits brackish water over sand, gravel, rock rubble, and swampy mud bottoms with thick vegetation (Ginsburg 1944, Van Tassell 2011, Robertson and Van Tassell 2023). The maximum total length is 2.5 cm (Murdy and Hoese 2003).
Threats Information
This restricted-range species is impacted by high levels of pollution throughout its distribution as a result of frequent small oil spills, raw sewage discharge, nutrient loading from agricultural processes, toxic cyanobacteria, and both heavy metal and hydrocarbon contamination (Laneve et al. 2022, Marín et al. 2022). Lake Maracaibo houses roughly 10,000 oil drilling platforms near its centre and is responsible for producing nearly 70% of Venezuela's gross national product through petroleum extraction (Marín et al. 2022). As a result, the lake is subjected to heavy oil tanker traffic and an increasing frequency of small oil spills (Laneve et al. 2022, Marín et al. 2022). In 1922 and 1972, large-scale spills resulted in over 100,000 barrels of oil each being released into the lake, demonstrating the looming possibility for future spills to affect much of this species' geographic distribution (Gundlach 2001). According to the U.S. Agency for International Development, oil pollution in the lake is considered "chronic", with spills being labelled as both "continuous and numerous" throughout (March et al. 2022). Though the environmental impact of these spills was recorded to have increased over the past five years, little has been done by the state oil company to address this issue (March et al. 2022).
Additionally, a growing coal industry in the tributary Guasare River, as well as petrochemical, metal-mechanical, hydrocarbon transportation, and gas processing industries situated along the lake have led to an increased risk for heavy metal pollution (Marín et al. 2022). Concentrations of arsenic, chromium, and lead have already been recorded as having a high potential ecological risk for estuarine taxa throughout the lake (Marín et al. 2022). Lake Maracaibo is currently considered a hypereutrophic environment (Echavez and Leal 2021) and is subjected to high levels of nutrient loading from tributary rivers, agricultural runoff, and raw sewage discharge from the three million people living in the city of Maracaibo, which is pumped directly into the Strait of Maracaibo at the lake's northernmost region (Marín et al. 2022). Constant dredging within the lake to accommodate for the high tanker traffic has led to the constant resuspension of nutrients and toxic metals, as well as a 300% increase in salinity over the last 40 years (Marín et al. 2022). This species is restricted to a severely impacted environment, which has been historically subjected to both consistent and sometimes large-scale pollution events. Pollution and subsequent habitat degradation throughout this species' distribution remains ongoing and increasing.
Use and Trade Information
This species is not utilized.
Conservation Actions Information
There are no species-specific conservation measures. Research is needed on the population status of this species.