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💧 Freshwater Endangered 🌡️ Temperate

Rhinogobius Biwaensis

Rhinogobius biwaensis Takahashi & Okazaki, 2017
Max Length
4.3 cm
Max Weight
-
Lifespan
-
Trophic Level
3.2
Depth
-
Climate
Temperate
Resilience
High
Vulnerability
11.00/100
Typical Length
-
Depth Zone
-

📖 Overview

Found in the lake mainly at 10-30 m, scarce in the mouths or lowest reaches of inflowing rivers, and in lagoons connected to Lake Biwa. From May to August, this species migrate to shallow water for spawning; all habitats are effectively lentic .

Scientific Name
Rhinogobius biwaensis
Authority
Takahashi & Okazaki, 2017
Habitat
Freshwater
Climate
Temperate
Body Shape
Elongated
IUCN Status
EN
Max Length
4.3 cm
Trophic Level
3.2
Resilience
High
Vulnerability
11.00/100
Salinity
0–0.5 ppt

🐟 Physical Description

Dorsal spines (total): 7; Dorsal soft rays (total): 7 - 9; Anal spines: 1; Anal soft rays: 8 - 9; Vertebrae: 25 - 27. This species is distinguished by the following characters: 26 (rarely 27) vertebrae; 18-22 (mostly 20-21) pectoral fin rays; 31-36 (usually 31-34, mode 32) longitudinal scales; absent or few predorsal scales; D1 low with non-filamentous spines, all almost of the same length except for shorter first and sixth or last spines in both sexes; pelvic disk with thin membranes, its frenum undeveloped with low, thin lamella; no mark on cheek; back and sides of body with 5-6 unclear dark saddles and 6-9 dark blotches; D1 without blotches but melanized to greater or lesser degree along the rays; dorsal edge of pectoral base with a small, dark spot tinged with blue metallic luster; breeding males yellow on suboperculum and branchiostegal region and on basal part of anal fin, blue on medial part of under jaw .: elongated; Cross section: oval.

🌀 Behaviour

Behavioural data for Rhinogobius Biwaensis is currently being reviewed.

🦐 Diet

aquatic invertebrates
small fish
algae
detritus

🥚 Reproduction

🐣 Oviparous
Spawning Season
spring
Spawn Location
Substrate
Fertilization
External

🌍 Habitat & Distribution

Freshwater; benthopelagic, usually 10 - 30 m . Temperate

🌿 Ecology

Zone Preferences
💧 Freshwater
Trophic Level
3.2±0.4

📐 Morphometrics

Length–Weight Relationship: W = 0.00813 × L3.08 (TL)
Max TL
4.3cm
Dorsal Spines
7
Dorsal Rays
8
Anal Spines
1
Anal Rays
9
Vertebrae
26

🌡️ Water Parameters & Tolerance

Salinity Range
0–0.5ppt

🛡️ Conservation Assessment

IUCN Category
Endangered
Assessment Date
2018

📊 Population Risk & Fisheries

Population Resilience
High
Minimum doubling time
Fishing Vulnerability
11.00/100
Low vulnerability
Trophic Level
3.2
Predator
Body Shape
Elongated
Climate Zone
Temperate
Described By
Takahashi & Okazaki, 2017

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