Actinopteri (ray-finned fishes) > Gobiiformes
(Gobies) > Gobiidae
(Gobies) > Gobionellinae
Etymology: Gymnogobius: Greek, gymnos = naked + Latin, gobius = gudgeon (Ref. 45335); opperiens: Name from Latin 'opperior' meaning to wait or expect, its present participle meaning 'waiting', alluding to it being recognized as new for more than 20 years and has long awaited formal description.
Environment: milieu / climate zone / depth range / distribution range
Marine; freshwater; brackish; demersal; amphidromous (Ref. 58909); depth range - m (Ref. ), usually - m (Ref. ). Temperate; 0°C -
Northwest Japan (NE and central Honshu and southern Hokkaido), Kuril Is. (Kunashir), southern Sakhalin, and southern Primorski Krai in Russian Far East.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 8.1 cm SL male/unsexed; (Ref. 81467)
(total): 6 - 7;
soft rays: 9 - 12. This species is distinguished by the following characters: base of caudal fine with a dark, y-shaped blotch and when fresh white spots on the pectoral fin near its insertion; head broad and depressed, the width greater than its depth; anterior oculoscapular canals reaching beyond postorbital region, opening through paired C, D, F, and G pores; right and left D pores distinct, separated by less than 1/3 orbital diameter; several sensory papillae in row 'n'; anteriorly protruding lower jaw beyond the upper one; maxilla extending posteriorly to or beyond posterior margin of eye; posterolateral end of mental flap indistinct; no fleshy, barbel-like processes behind chin; body with a series of broad bands formed by dark pigment patches; dusky caudal fin with dark blotches forming distich bands; predorsal scales 19-26; longitudinal scale series 71-78; modal vertebral count 15 + 18; first dorsal fin often with 6 spines, anteriormost pterygiophore usually inserted in 4th interneural space; modal second dorsal fin ray I,11, anteriormost pterygiophore usually inserted in 11th interneural space; modal anal fin ray count I,11, origin anterior to 3rd soft ray or second dorsal; first dorsal fin with distinct oblique bands, a dark blotch on posterior margin (Ref. 81467).
Often hidden among rocks in shallow, fast-moving, rock bottom streams and rivers. Collected in water temperatures exceeding 30°C (Ref. 81467).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Stevenson, D.E., 2002. Systematics and distribution of fishes of the Asian goby genera Chaenogobius and Gymnogobius (Osteichthyes: Perciformes: Gobiidae), with the description of a new species. Spec. Divers. 7(3):251-312. (Ref. 81467)
IUCN Red List Status (Ref. 124695)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82805
= 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01023 (0.00444 - 0.02358), b=3.05 (2.86 - 3.24), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245
Trophic level (Ref. 69278
): 3.2 ±0.3 se; based on size and trophs of closest relatives
Resilience (Ref. 120179
): High, minimum population doubling time less than 15 months (Preliminary K or Fecundity.).
Vulnerability (Ref. 59153
): Low vulnerability (21 of 100) .