|Scientific Name:||Eucyclogobius newberryi (Girard, 1856)|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer(s):||Smith, K. & Darwall, W.R.T.|
|Facilitator/Compiler(s):||Hammerson, G.A. & Ormes, M.|
Listed as Near Threatened because extent of occurrence is less than 5000 km2, area of occupancy probably is less than 500 km2, and habitat is subject to various threats that may reduce its quality or quantity. However, the number of locations is large, distribution is not severely fragmented, population size is unknown but not particularly small, and current population trend is uncertain (but probably within the natural range of variation), so the species does not currently meet all the criteria required for a threatened category.
|Previously published Red List assessments:|
|Range Description:||Range includes discrete brackish coastal lagoons and coastal creeks in California (~1,600 mile coast) from Tillas Slough (mouth of the Smith River), Del Norte County) near the Oregon border south to Cockleburr Canyon (northern San Diego County (formerly farther south, to Agua Hedionda Lagoon, San Diego County) (Swift et al. 1989, USFWS 2007). The species is naturally absent (due to lack of suitable habitat) between the Eel River (Humboldt County) and Ten Mile River (Mendocino County), between Lagoon Creek (Mendocino County) and Salmon Creek (Sonoma County), and between the Salinas River (Monterey County) Monterey Bay and Arroyo del Oso (San Luis Obispo County) (Swift et al. 1989, USFWS 2007). Habitat loss and other anthropogenic factors have eliminated the species from the area between northern Los Angeles County and northern San Diego County (USFWS 2007).|
|FAO Marine Fishing Areas:|
Pacific – eastern central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Historically this species occurred in at least 135 localities; current number of extant populations is believed to be about 112 (USFWS 2011).|
Total adult population size is unknown but likely at least several thousand.
Recent surveys indicate that this species no longer occurs in 17 percent of the 135 historically documented locations (USFWS 2011). Of the populations considered to be permanently extirpated, most were extirpated prior to 1970, before regulations protecting the environment were promulgated (USFWS 1999). The northern range limit has not changed; the southern limit formerly was about 15 kilometres farther south (USFWS 2007).
No range-wide, long-term monitoring program is currently being conducted; data on population dynamics are limited (USFWS 2007). Populations are naturally highly dynamic. Local populations sometimes become extirpated but later are recolonized from nearby source populations (Lafferty et al. 1999). When lagoons are breached due to flood events during the rainy season, tidewater goby populations decrease and then recover during the following summer (Lafferty et al. 1999). Trend over the past 10 years or three generations is uncertain but probably within the natural range of variation (three generations span fewer than 10 years).
|Current Population Trend:||Stable|
|Habitat and Ecology:||This benthic fish occurs in small coastal lagoons, lower reaches of streams, and uppermost portions of large bays. It is most abundant in the upper ends of lagoons created by small coastal streams (Swift, in Moyle 1976). In lower sections of coastal streams, it occurs in fresh to brackish water (preferably less than 10 ppt). It occurs in vegetated pools of slow (but not stagnant) areas of streams and has been documented in ponded freshwater habitats as far as 8 km upstream from San Antonio lagoon in Santa Barbara County. Generally it occurs in water 25-100 cm deep. It can complete the life cycle in fresh or brackish water. It tolerates temperatures of 8-23 C and salinities of 0-40 ppt. It prefers mud substrates and areas of high dissolved oxygen. There is no explicit marine life history phase; hence, frequency of population interactions and genetic exchange among different coastal lagoon subpopulations is restricted (but sometimes does occur from nearby subpopulations; Lafferty et al. 1999, McCraney and Kinziger 2009). |
Spawning occurs on substrates of coarse sand, in burrows dug by males usually in water 25-50 cm deep (Swift et al. 1989). Larvae are found midwater around vegetation until they become benthic (Swift et al. 1989).
|Movement patterns:||Not a Migrant|
This species is threatened, or potentially threatened, by: (1) coastal development projects that result in the loss or alteration of coastal wetland habitat; (2) water diversions and alterations of water flows upstream of coastal lagoons and estuaries that negatively impact the species' breeding and foraging activities; (3) groundwater overdrafting; (4) channelization of the rivers where the species occurs; (5) discharge of agricultural and sewage effluents; (6) cattle grazing and feral pig activity that results in increased sedimentation of coastal lagoons and riparian habitats, removal of vegetative cover, increased ambient water temperatures, and elimination of plunge pools and undercut banks utilized by Tidewater Goby; (7) introduced species that prey on Tidewater Goby (e.g., bass (Micropterus spp.) and crayfish (Cambarus spp.)); (8) inadequacy of existing regulatory mechanisms; (9) drought conditions that result in the deterioration of coastal and riparian habitats; and (10) competition with introduced species, such as the yellowfin goby (Acanthogobius flavimanus) and chameleon goby (Tridentiger trigonocephalus) (USFWS 2007, 2011).
Current laws and regulations have reduced or eliminated both large- and small-scale habitat loss and alteration. However, some threats to the Tidewater Goby are still ongoing. These include limited loss and alteration of habitat resulting from development projects, flood control, anthropomorphic breaching of coastal lagoons, and freshwater withdrawal. Also, predation by and competition with native and non-native species continue to be a concern (USFWS 2007).
About 50 percent of the remaining populations are considered vulnerable to extinction due to severe habitat degradation (USFWS 2007).
Populations in large habitats that are close to other occupied habitats are most likely to persist, but habitat alteration and introduced species may eliminate the species from even large habitats (Lafferty et al. 1999).
Failure of Tidewater Gobies to recolonize habitats after local extirpation may result of habitat degradation of the extirpated locality, rather than an inability to recolonize.(Lafferty et al. 1999).
|Conservation Actions:||"The long-term persistence of the tidewater goby requires protection and, in some cases, restoration of its suitable habitat. In certain localities, particularly in southern California, restoration of degraded habitat (e.g., removal of fill, reestablishment of natural semi-open connections between lagoon and ocean) will be necessary for establishment of viable metapopulations. In some locations, reintroduction of tidewater gobies to formerly occupied habitat, or restoration of natural dispersal mechanisms and pathway, may be necessary to establish viable populations where they have been extirpated in the past. Removal of fill material, including the relocation or removal of levees used to drain former salt marsh and other suitable habitat, may be considered on a site-by-site basis to reestablish extirpated populations, or restore connectivity within fragmented habitats supporting historically interconnected metapopulations. Coastal developments should consider the habitat needs of the tidewater goby when they have the potential to change or affect coastal hydrologic patterns, where they may contribute pollutants to the aquatic environment, or where they may require filling of suitable goby habitat. Exotic species that prey upon or compete with tidewater gobies may require control, on a local or regional scale, where they have the potential eliminate gobies, or where they may preclude successful reestablishment of tidewater gobies within their historic habitat. Restoration projects, especially those designed to restore or enhance other resource values, should carefully consider the needs of tidewater gobies where they occur, or where reestablishment of tidewater goby populations is an important recovery objective". Source: U.S. Fish and Wildlife Service (http://www.fws.gov/arcata/es/fish/Goby/goby.html).|
|Citation:||NatureServe. 2014. Eucyclogobius newberryi. The IUCN Red List of Threatened Species 2014: e.T8165A18233437.Downloaded on 12 December 2017.|
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