The round goby Neogobius melanostomus is one of the most wide-ranging invasive fish on earth, with substantial introduced populations within the Laurentian Great Lakes watershed, the Baltic Sea and several major European rivers. Rapid expansion and deleterious ecosystem effects have motivated extensive research on this species; here this research is synthesized. Maps of the global distribution are provided and the invasion history of N. melanostomus, which spread more rapidly at first in North America, but has undergone substantial expansion over the past decade in the Baltic Sea, is summarized. Meta-analyses comparing their size at age, diet, competitors and predators in North American and European ecosystems are provided. Size at age is region specific, with saline habitats typically supporting larger and faster growing individuals than fresh water. Neogobius melanostomus prey differs substantially between regions, demonstrating a capacity to adapt to locally abundant food sources. Neogobius melanostomus comprise at least 50% of the diet of eight taxa in at least one site or life stage; in total, 16 predator taxa are documented from the Laurentian Great Lakes v. five from Eurasia. Invasive N. melanostomus are the only common forage fish to heavily exploit mussels in the Laurentian Great Lakes and the Baltic Sea, facilitating the transfer of energy from mussels to higher trophic levels in both systems. Neogobius melanostomus morphology, life history, reproduction, habitat preferences, environmental tolerances, parasites, environmental effects, sampling strategies and management are also discussed. Neogobius melanostomus inhabit a wide range of temperate freshwater and brackish-water ecosystems and will probably continue to spread via ballast water, accidental bait release and natural dispersal worldwide. Climate change will probably enhance N. melanostomus expansion by elevating water temperatures closer to its energetic optimum of 26 C. Future research needs are presented; most pressing are evaluating the economic effects of N. melanostomus invasion, determining long-term population level effects of egg predation on game-fish recruitment and comparing several variables (density, ecological effects morphology and life history) among invaded ecosystems. This review provides a central reference as researchers continue studying N. melanostomus, often as examples for advancing basic ecology and invasion biology.
Review: Goby
Historically, tidewater gobies are known to have inhabited 150 lagoons and estuaries along the California coast. In the 1980s, researchers discovered that tidewater gobies were disappearing from many locations. In 1994, the tidewater goby was listed as endangered under the Endangered Species Act.
The Service's efforts to better understand the tidewater goby have resulted in increased levels of surveys and monitoring in nearly every lagoon along the California coast. These efforts have led to the discovery of the species in locations where tidewater gobies were not known to be living. The Service is working alongside other federal agencies, state agencies, conservation organizations and universities to protect and recover the tidewater goby.
The lifecycle of the tidewater goby is keyed to the annual cycle of the lagoons and estuaries in which they live. While adults can tolerate high salinity levels for shorter periods of time, larval and juvenile tidewater gobies cannot. Reproduction occurs in still water with no to low-salinity and mild-temperatures. The peak of spawning activity occurs during the spring, when lagoons close to the ocean, and again in late summer.
As in many other species of goby, the male tidewater goby constructs a burrow and provides parental care for the eggs. Male tidewater gobies dig breeding burrows in clean, coarse sand, using their mouths to move the sand. The burrows are small, measuring 0.02 inches in diameter.
The tidewater goby is a small, elongate, grey-brown fish. Juveniles and adults are semitranslucent gray, brown or olive with black mottling. Females often appear darker than males, developing black or dark coloring on the body and fins during breeding. Tidewater gobies have large pectoral fins and fused pelvic fins that form a sucker-like disc below the chest and belly.
The tidewater goby is endemic to California, ranging from northern Del Norte County south to San Diego County. Tidewater gobies are absent from areas where the coastline is steep and streams do not form lagoons or estuaries.
The present study recorded the population of the goby fish (Perciformes: Gobiidae), Eutaeniichthys cf. gilli Jordan & Snyder, 1901, from the tunnel burrowed by the mud shrimp Austinogebia edulis Ngo-Ho and Chan, 1992 in a mudflat in Shengang and Wangong of Changhua County, western Taiwan. This finding is not only a new record of the genus in Taiwan, it is also the first record of this species in a mudflat near an industrial park. In total, 56 individuals of E. cf. gilli were collected from June 2016 to September 2018. Morphological traits of males and females were measured. The resin casting method trapped bodies of E. cf. gilli that were present in the tunnel burrow and proved that the fish inhabits burrows of the mud shrimp A. edulis. In addition, a species of snapping shrimp was also found in the same tunnel. Symbiotic interaction may occur between E. cf. gilli, A. eduli and the snapping shrimp. The China Coastal Current (CCC) runs along the coastlines of Japan, Korea, China, and reaches western Taiwan during the northeast monsoon period. The CCC, therefore, might play an important role in the biogeographic distribution of E. cf. gilli in the western Pacific Ocean. Since E. cf. gilli is listed in the Red List as an endangered species of Japan for many years, Taiwan waters may provide a refuge for this fish species warranting a broader investigation. Since Taiwan is some distance away from the previously recorded locations in Japan, Korea, the Yellow Sea, and the Bohai Sea, a phylogenic analysis is warranted for population and species differentiation in the future.
Citation: Tseng L-C, Huang S-P, Das S, Chen I-S, Shao K-T, Hwang J-S (2019) A slender symbiotic goby hiding in burrows of mud shrimp Austinogebia edulis in western Taiwan. PLoS ONE 14(7): e0219815.
A total of 56 individuals of E. cf. gilli were collected from the areas of Shengang (24.168094 oN, 120.457894 oE) and Wangong (23.968126 oN, 120.323173 oE) in western Taiwan (Fig 2). Five lots were collected: 8 individuals on June 1, 2016; 7 individuals on November 3, 2016; 12 individuals on February 22, 2017; 6 individuals on June 13, 2018; and 23 individuals on September 21, 2018. The sites were characterized as mudflat areas dominated by the mud shrimp A. edulis [12]. Samples of goby E. cf. gilli were collected carefully from mud shrimp burrows by using a shovel and hand net (mesh size: 0.5 mm) during low tide period. Eutaeniichthys cf. gilli always appeared at the surface of the pool with turbid underground seawater when digging more than 60 cm deep.
The present study identified E. cf. gilli inhabiting a wetland near the industrial park and hiding in mud shrimp burrows. This species belongs to the family Gobiidae, which is a highly diverse bony fish family worldwide [48]. However, gobiids are important but frequently misidentified and their biology and ecological niche are poorly understood [49]. There are about 247 species from 77 genera in the gobiid family in Taiwan [50]. Historical records of the goby, E. cf. gilli, along the coast of Taiwan are not available. This new record for Taiwan is thus the southernmost record of the species in the world. However, E. gilli in the area of southern Ryukyu is still inadequately known, and our study is the first to document E. cf. gilli in waters of this region. Previous in situ studies found that E. gilli utilized mud shrimp burrows as a breeding habitat during the period from May to August [21]. A laboratory study found that E. gilli spent 25 to 50% of its time in the burrow of the mud shrimp [33]. The burrow of mud shrimp is an important habitat that E. gilli utilized as a nesting site for spawning and deposition of eggs in the shallow tidal creek of Obitsu-gawa River estuary [31]. The E. gilli takes shelter inside the burrows of A. edulis which benefits their reproduction.
Previous investigations have shown the utility of burrows of upogebiid and callianassid shrimps by E. gilli [21, 22, 59]. The records show that E. gilli has a symbiotic relationship with the mud shrimp Upogebia major [60], and with Upogebia yokoyai [33, 34, 59] in Japan. Shrimp burrows are used by several gobies for symbiotic associations [61]. The records found more than 120 gobiid fishes in symbiosis with alpheid shrimps; the shrimps built burrows and share those with gobies as a refuge providing shelter, gobies give feedback on this symbiotic relationship with a warning signal when predators appear [62]. The mutual association is beneficial to one partner, or both shrimp and goby [63]. The present study is the first to report the associations of E. cf. gilli with the mud shrimp A. edulis burrows worldwide. The records show that the symbiotic hosts of E. gilli can be diverse and are not specific. This association would allow a sympatric coevolution and biogeographic codistribution of goby E. cf. gilli and its host (A. edulis).
The resin casting method has been applied to study the burrow architecture of different mud shrimps, such as Austinogebia edulis [16], Upogebia major [15], and Upogebia omissa [64]. In general, resin casting of mud shrimp burrows showed that they were approximately Y-shaped, with an upper U-part [15, 16, 64]. The present study applied this method to catch E. cf. gilli in burrows of the mud shrimp. The results found that the occurrence rate of E. cf. gilli was 10%. The goby prefers burrows with depth longer than 50cm. Observations in the laboratory found that the behavior of E. cf. gilli was very agile. They might easily escape from through the other opening of the burrow. Designing a suitable method to avoid underestimating the number of E. cf. gilli populations and those inhabiting burrows will be a necessary future task. 2ff7e9595c
Comentários