Classification / Names
Common names | Synonyms | Catalog of Fishes (gen., sp.) | ITIS | CoL | WoRMS | Cloffa
Actinopterygii (ray-finned fishes) > Ophidiiformes
(Cusk eels) > Bythitidae
(Viviparous brotulas) > Bythitinae
Etymology: Grammonus: Greek, gramma = signal, mark + Greek, onos = hake; yunokawai: Named for Mr. Kyo Yunokawa, of Ie-shima Diving Center. More on author: Nielsen.
Environment: milieu / climate zone / depth range / distribution range
Marine; demersal; depth range ? - 20 m (Ref. 75999). Temperate
Countries | FAO areas | Ecosystems | Occurrences | Point map | Introductions | Faunafri
Northwest Pacific: Japan.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 9.8 cm SL (female)
Morphology | Morphometrics
soft rays: 64;
Vertebrae: 41. This species has the following characters: Dorsal-fin rays 83; anal-fin rays 64; caudal fin rays 9; pectoral 23-24; vertebrae 12 + 29; anterior anal fin ray is placed below 23rd dorsal fin ray; maximum depth of head is 32.0% SL; predorsal length 41.5% SL; interorbital width 10.5% SL; height of posterior margin of maxilla 8.4% SL (Ref. 75999).
Known only from one female specimen with ovaries containing eggs up to about 0.5 mm in diameter and apparently with no embryos. It was caught by hand in the back of the cave in absolute darkness. The head and lateral line pore systems are well developed, also the sensory papillae on the head and body, indicating adaptation to the lightless environment
Also observed and caught were a shrimp Parhippolyte misticia and the fishes Pseudamia hayashiiand Apogon evermanni (Ref. 75999).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Nielsen, J.G., 2007. Grammonus yunokawai (Ophidiiformes: Bythitidae), a new marine cave fish from the Ryukyu Islands. Ichthyol. Res. 54(4):374-379. (Ref. 75999)
IUCN Red List Status (Ref. 119314)
CITES (Ref. 115941)
Threat to humans
CountriesFAO areasEcosystemsOccurrencesIntroductionsStocksEcologyDietFood itemsFood consumptionRation
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates of some properties based on models
Phylogenetic diversity index (Ref. 82805
= 0.5005 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00389 (0.00180 - 0.00842), b=3.12 (2.94 - 3.30), in cm Total Length, based on all LWR estimates for this body shape (Ref. 93245
Trophic Level (Ref. 69278
): 3.4 ±0.5 se; Based on size and trophs of closest relatives
Resilience (Ref. 69278
): High, minimum population doubling time less than 15 months (Preliminary K or Fecundity.).
Vulnerability (Ref. 59153
): Low vulnerability (19 of 100) .