Yellowfin Goby - Acanthogobius flavimanus (Temminck and Schlegel)

Page 34-2 Gobies TR9

Spawning

Location Tidal mudflats of coast and estuary (Miyazaki 1950; Dotsu and Mito 1955); tidal flats of south and central San Francisco Bay, San Pablo Bay; these and Tomales Bay, Elkhorn Slough and Moss Landing Harbor.
Season February through May in Japan (Miyazaki 1940); January through March in Kyushu, Japan (Dotsu and Mito 1955); larvae collected from December through July.
Temperature 7.5-13 C (Dotsu and Mito 1955); ca. 10-15 when prolarvae were collected.
Salinity Seawater to mesohaline.
Substrates Hollow bamboo segments (Miyazaki 1940); sand, mud, and ceramic tubes (Dotsu and Mito 1955); mostly in sand and mud bottoms.
Fecundity 6,000-32,000 (Miyazaki 1940); 18,000 for a single female 156 mm TL.

Eggs

Shape Spherical for mature eggs, teardrop or club-shaped for fertilized eggs (Dotsu and Mito 1955).
Diameter 5.0-5.8 mm in long axis; 0.9-1.0 mm (average of 0.96 mm) in short axis (Dotsu and Mito 1955).
Yolk Yellowish, granular.
Oil globule Many oil globules in early embryo stage; consolidated into one in late embryo stage (Dotsu and Mito 1955).
Chorion Transparent, smooth, thick and elastic (Dotsu and Mito 1955).
Perivitelline space Very wide in long axis and narrow in short axis in early developmental stages (Dotsu and Mito 1955).
Egg mass Deposited on roof or wall of breeding chamber, in single layers; may be very dense per unit area (Dotsu and Mito 1955).
Adhesiveness Adhesive at anchoring point with short filaments (Dotsu and Mito 1955).
Buoyancy Demersal; attached to substrate (Dotsu and Mito 1955).

Larvae

Figure 34-1. Prolarva, 5.5 mm TL.
Figure 34-2. Postlarva, 6.8 mm TL.
Figure 34-3. Postlarva, 8 mm TL.
Figure 34-4. Postlarva, 23.2 mm TL.

Length at hatching 4.6-5.0 mm TL (Dotsu and Mito 1955); 4.4 mm TL.
Snout to anus length 46-48 percent of TL of prolarvae and postlarvae.
Yolk sac Spherical, in thoracic region.
Oil globule Single oil globule in anterior yolk sac (Dotsu and Mito 1955).
Gut Straight.
Air bladder Small, oval, just to rear of pectorals in prolarvae; large, oval, midway between pectorals and anus in postlarvae.
Teeth Small, pointed in postlarvae.
Size at completion of yolk-sac stage Ca. 5.0 mm TL; 5.0-5.5 mm.
Total myomeres 32 (Dotsu and Mito 1955); 31-33.
Preanal myomeres 14 (Dotsu and Mito 1955); 13-14.
Postanal myomeres 18 (Dotsu and Mito 1955); 18-19.
Last fin(s) to complete development Fused pelvic fin.
Pigmentation Stellate melanophores on thoracic, postanal, and caudal regions and dorsal anus; in early postlarvae, a large melanophore midway between anus and caudal fin on the ventrum and one on dorsum; fused in late postlarvae.
Distribution Pelagic, found mostly in seawater to mesohaline in central and south San Francisco Bay and San Pablo Bay; some drift into Suisun Bay. They were also taken in Moss Landing Harbor and Elkhorn Slough.

Juveniles

Figure 34-5. Juvenile, 22.3 mm TL.

Dorsal fin VIII, 14 (Dotsu and Mito 1955).
Anal fin 12-13 (Dotsu and Mito 1955); I, 11-12.
Pectoral fin 20-22.
Mouth Maxillary does not extend beyond the center of eyes (Moyle 1976); terminal to subterminal, large.
Vertebrae 33 (Dotsu and Mito 1955); 32-34 (R. Lavenberg, Los Angeles County Museum of Natural History, personal communication, 1980).
Distribution Benthic (burrows) and epibenthic along Pacific Coast adjacent to central and south San Francisco Bay, San Pablo Bay, Suisun Bay, the Delta, and lower reaches of tributaries, irrigation ditches, and canals. Yellowfin goby are also found in Rodeo Lagoon, Tomales Bay, and Moss Landing Harbor-Elkhorn Slough.

Life History

The yellowfin goby, an estuarine fish native to Japan, Korea, and northern China (Tomiyama 1936; Miyazaki 1940; Fowler 1961)was accidentally introduced into the Sacramento-San Joaquin estuary in the 1950s, through the ballast systems of ships (Brittan et al. 1963). Currently, this species is not only abundant within the estuary, but also has been observed along the coast from Elkhorn Slough to Tomales Bay (Miller and Lea 1972; Kukowski 1972). A second yellowfin goby population is reported in Los Angeles, Long Beach Harbor, and Newport Bay (Haaker 1979), and was conceivably established in the same manner one in San Francisco Bay. In this study yellowfin goby have been observed throughout the estuary, including the lower portion of the tributaries draining into the estuary. No specimens were collected in O'Neill Forebay and San Luis Reservoir in 1979-1981, although the species had previously been reported from these locations (Brittan et al. 1970; Moyle 1976). Judging from the larvae collected in this study, spawning is estimated to occur from December through July in the Sacramento-San Joaquin estuary. Spawning of the yellowfin goby was observed by Dotsu and Mito (1955) in Kyushu, Japan; eggs are deposited in a single layer on the wall or roof of a Y-shaped burrow, ca. 15-35 cm deep, construced in intertidal mudflats. The female may leave the burrow after spawning or may join the male in guarding the eggs. The incuba- tion period is approximately 28 days at 13 C. Yellowfin goby larvae are pelagic (Miyazaki 1940; Dotsu and Mito 1955). In this study, newly hatched larvae swam out of the burrow and remained near the bottom. Yellowfin goby larvae were seldom caught in surface plankton tows, but were captured by a pump-net sampling device in which the depth of the intake pipe could be adjusted; goby larvae were often collected by this device when the intake pipe was located near the bottom. Yellowfin goby prolarvae were found in higher-salinity waters such as central and south San Francisco Bay, San Pablo Bay, and near the sandbar of Rodeo Lagoon. After the yolk sac is absorbed, the larvae disperse rapidly. Some larvae begin to ascend to Carquinez Strait and Suisun Bay as early as late February. This upstream movement is similar to that of the naked goby, Gobiosoma bosci, along the mid-Atlantic Coast, which uses tidal changes to move into the estuaries. The larvae float on the surface of the water column during flood tide and descend to near the bottom while the tide ebbs (Massman et al. 1963). Juveniles settle on the bottom at about 13 cm TL (Miyazaki 1940). Pelvic fins fuse into a sucking disc, and the fish are able to cling to substrates or crawl into burrows. Juvenile yellowfin goby prefer tidal sloughs with a muddy bottom and peatmoss banks. Brittan et al. (1970) reported that the yellowfin goby has spread as far as San Luis Reservoir, Merced County. Apparently, some juveniles traveled through the Tracy pumping station and were transported via the canal systems further south. Major food items for small juvenile yellowfin goby are harpacticoid copepods (Miyazaki 1940) and other copepods (Dotsu and Mito 1955); the large juveniles eat amphipods, mysid shrimp, and small fish. In Japan, some yellowfin goby reach maturity after one year (Miyazaki 1940; Dotsu and Mito 1955); however, other populations mature after two yers, and the maximum life span is 3-4 years (Miyazaki 1940). The majority die after spawning (Miyazaki 1940). In the California population, yellowfin goby mature in 2-3 years (Brittan et al. 1970). Mature yellowfin goby collected in the study generally ranged from 85 to 204 mm TL and were one year or older (M. Carlin, personal communication, 1979). One specimen was 288 mm TL. Yellowfin goby are considered as an important game fish and human food in Japan (Miyazaki 1940; Dotsu 1978). In California they are used mainly as bait fish and commonly called bullhead. Some Asians in the San Francisco Bay area catch and consume yellowfin goby (Moyle 1976). Yellowfin goby adapt well to different salinities and sudden changes in salinity (Brittan et al. 1970). This species shares a similar habitat with other gobies, marine cottids, and surfperches in the higher-salinity bays, and with freshwater sculpins, catfishes, cyprinids, osmerids, and striped bass in the lower-salinity areas. The impact of yellowfin goby on the local fish community is poorly known at the present. Since yellowfin goby larvae were not found in the upper estuary and reproduction had almost totally ceased in Rodeo Lagoon when the salinity was 5.0 ppt or less (Wang 1982), it appears that the yellowfin goby's spawning migration in the Sacramento-San Joaquin estuary is from fresher to more saline water. In a landlocked freshwater environment they may die off eventually because of lack of spawning success. If this hypothesis is correct, the yellowfin goby population may not be a problem in California's inland freshwater systems. This species may expand its distribution along the coast.

References

Brittan et al. 1963, 1970; Dotsu (or Dotu) 1978; Dotsu and Mito 1955; Fowler 1961; Haaker 1979; Kukowski 1972; Messersmith 1963; Miller and Lea 1972; Miyazaki 1940; Moyle 1976; Tomiyama 1936; Wang 1982.