Persistence of native fishes in small streams of the urbanized San Francisco Estuary, California: acknowledging the role of urban streams in native fish conservation

2011 ◽  
Vol 21 (5) ◽  
pp. 472-483 ◽  
Author(s):  
Robert A. Leidy ◽  
Kristina Cervantes-Yoshida ◽  
Stephanie M. Carlson

<em>Abstract.</em>—We examined assemblage patterns of early life stages of fishes for two major tributaries of the upper San Francisco Estuary: (1) Sacramento River channel, and (2) Yolo Bypass, the river’s seasonal floodplain. Over four hydrologically diverse years (1999–2002), we collected 15 species in Yolo Bypass egg and larval samples, 18 species in Yolo Bypass rotary screw trap samples, and 10 species in Sacramento River egg and larval samples. Fishes captured included federally listed species (delta smelt <em>Hypomesus transpacificus </em>and splittail <em>Pogonichthys macrolepidotus</em>) and several game species (American shad <em>Alosa sapidissima</em>, striped bass <em>Morone saxatilis</em>, crappie <em>Pomoxis </em>spp., and Chinook salmon <em>Oncorhynchus tshawytscha</em>). As in other regions of the estuary, alien fish comprised a large portion of the individuals collected in Yolo Bypass (40–93% for egg and larval net samples; 84–98% for rotary screw trap samples) and Sacramento River (80–99% for egg and larval net samples). Overall ranks of species abundances were significantly correlated for Yolo Bypass and Sacramento River, suggesting that each assemblage was controlled by similar major environmental factors. However, species diversity and richness were higher in Yolo Bypass, likely because of a wider variety of habitat types and greater hydrologic variation in the floodplain. In both landscapes, we found evidence that timing of occurrence of native fishes was earlier than aliens, consistent with their life history and our data on adult migration patterns. We hypothesize that Yolo Bypass favors native fishes because the inundation of seasonal floodplain typically occurs early in the calendar year, providing access to vast areas of spawning and rearing habitat with an enhanced food web. Conclusions from this analysis have implications for the management of aquatic biodiversity of tributaries to the San Francisco Estuary and perhaps to other lowland rivers.


<em>Abstract</em>.—The Colorado River of Texas originates in the northwest portion of the state and runs southeasterly across the environmentally sensitive Edwards Plateau ecoregion, eventually emptying into Matagorda Bay on the Gulf of Mexico. The Texas Parks and Wildlife Department (TPWD) and other conservation partners have worked for decades to conserve native fishes in the river and its associated estuary. The river and its tributaries are also the major water source for millions of people, and portions of the watershed are undergoing unprecedented human population growth and a concomitant increased demand for water. Drought, which is a frequent occurrence in Texas, exacerbates these effects. Providing adequate streamflow and water quality to conserve aquatic species while still fulfilling obligations for municipal, industrial, agricultural, hydropower, and recreational water use is increasingly challenging. Since the 1980s, the TPWD has promoted water management policies in the watershed to benefit aquatic life, conducted research to maintain a sound ecological environment for fish and other aquatic taxa, provided technical guidance and financial incentives to private landowners to improve land practices that benefit water quality and quantity, and improved public access to foster increased stewardship of the river. The TPWD has also collaborated with researchers to study the potential impacts of altered hydrology on two endemic, flow-dependent fish species, Guadalupe Bass <em>Micropterus treculii </em>and Blue Sucker <em>Cycleptus elongatus</em>. Two portions of the Colorado River watershed have been identified as native fish conservation areas in part for persistence of populations of these native fishes. Outcomes from these activities are now being leveraged using federally funded research and conservation delivery programs to further advance the conservation of native fish populations and other aquatic life in native fish conservation areas of the Colorado River watershed.


2004 ◽  
Vol 204 ◽  
pp. 970-979 ◽  
Author(s):  
Steven D. Culberson ◽  
Theodore C. Foin ◽  
Joshua N. Collins

2021 ◽  
Vol 9 ◽  
Author(s):  
J. Louise Conrad

When we think of engineers, we think of making a machine, like a car. Are there engineers for ecosystems? When an organism can make big changes to its environment, we call it an ecosystem engineer. In aquatic ecosystems like the San Francisco Estuary, underwater plants can be important ecosystem engineers because they can change water flow and water clarity. In the Estuary, a plant called Brazilian waterweed, which was introduced by humans, is one of the most important ecosystem engineers. With its leaves and stems, this plant traps tiny particles floating in the water, making the water clearer. Clearer water has made it easier for more plants to grow and these changes helped some non-native fish species to increase in number, while some native species declined. Introduction of Brazilian waterweed has led to an entirely different ecosystem, which has also affected how people use and take care of the Estuary.


<em>Abstract</em>.—Native fish conservation areas in the Chihuahuan Desert of Texas were identified and designated as part of a statewide network of focal watersheds uniquely valued in preservation of Texas freshwater fish diversity. Native fish conservation areas represent a holistic, multispecies, and habitat-based approach to native fish conservation that encourages and facilitates coordination among landowners, nongovernmental organizations, state and federal agencies, universities, and local governments to achieve landscape-scale conservation within focal watersheds. This approach to native fish conservation provides an effective method for addressing the common nature and magnitude of threats facing species and their habitats in freshwater systems. Desert fishes and their habitats are particularly susceptible to habitat alteration, especially anthropogenic land use and water consumption patterns, which continue to create conservation challenges. The strategic and science-based conservation strategies embodied by the native fish conservation areas approach represent an innovative path forward for addressing the conservation needs of native fishes and their habitats in the Chihuahuan Desert of Texas. In this chapter, we describe six native fish conservation areas designated within the Chihuahuan Desert of Texas and profile multiagency conservation planning and delivery that has substantially increased the scope and scale of conservation investments for restoration and protection of native fishes and their habitats in the region.


Author(s):  
Brian Mahardja ◽  
Andrew Goodman ◽  
Alisha Goodbla ◽  
Andrea Schreier ◽  
Catherine Johnston ◽  
...  

Biological invasion by non-native species has been identified as one of the major threats to native fish communities worldwide. The fish community of San Francisco Estuary is no exception, as the estuary has been recognized as one of the most invaded on the planet and the system has been impacted significantly by these invasions. Here, we summarize the introduction and probable establishment of a new species in the Sacramento–San Joaquin Delta, the Bluefin Killifish (Lucania goodei), as discovered by the US Fish and Wildlife Service Delta Juvenile Fish Monitoring Program (DJFMP). The DJFMP has conducted a large-scale beach seine survey since 1976, and it is the longest-running monitoring program in the San Francisco Estuary that extensively monitors the shallow-water nearshore habitat. Possibly introduced as discarded aquarium fish within the vicinity of the Delta Cross Channel, Bluefin Killifish is a close relative of the Rainwater Killifish (Lucania parva), another non-native fish species that has been present in the San Francisco Estuary system for decades. Studies in their native range suggest that Bluefin Killifish will fill a similar niche to Rainwater Killifish, albeit with a more freshwater distribution. The potential ecological impact of Bluefin Killifish remains unclear in the absence of additional studies. However, we have been able to track the spread of the species within the Sacramento–San Joaquin Delta through the existence of long-term monitoring programs. Our findings demonstrate the value of monitoring across various habitats for the early detection and proactive management of invasive species.


PLoS ONE ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. e0234673
Author(s):  
Ted Sommer ◽  
Rosemary Hartman ◽  
Michal Koller ◽  
Michael Koohafkan ◽  
J. Louise Conrad ◽  
...  

Author(s):  
J. Barile ◽  
R. Vega ◽  
P. De los Ríos-Escalante

Abstract The Toltén river is located in the 137 years old Araucania region, Chile (38° S), and is characterized by low alterations through human interference due agriculture and towns in its surrounding basin, the presence of native fishes and salmonids, and by its lake effluent regime originated from Villarrica lake. The aim of the present study was to make a review of ecological role of the benthic inland water macroinvertebrates as preys for native fishes of the River Toltén, in order to understand their importance in the ecosystem of the river. The literature revealed that the main prey for native fishes are Chironomidae larvae, nevertheless there are not specific reports for Tolten river. The exposed results are similar with similar native species for Patagonia, and these native species would have prey for introduced salmonids, or these species would have prey competition with introduced salmonids in according to the literature descriptions for Argentinean and Chilean Patagonia.


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