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🌊 Marine Least Concern 🍽️ Edible 🎣 Game Fish ⚠️ Venomous ⚡ Venomous 🌡️ Tropical

Mottled spinefoot

Siganus fuscescens Houttuyn, 1782
Max Length
40 cm
Max Weight
1.2 kg
Lifespan
-
Trophic Level
2
Depth
1–50 m
Climate
Tropical
Resilience
High
Vulnerability
21.00/100
Typical Length
25 cm
Depth Zone
reef

📖 Overview

Inhabits algal and seagrass flats and shallow lagoon and coastal reefs . Forms schools. Mainly diurnal. Juveniles feed on filamentous algae, adults feed on leafy algae and seagrasses . Commercially cultured in Japan. Commonly found in large estuaries . Anterolateral glandular groove with venom gland .

Scientific Name
Siganus fuscescens
Authority
Houttuyn, 1782
Habitat
Marine
Climate
Tropical
Body Shape
Short and / or deep
IUCN Status
LC
Max Length
40 cm
Max Weight
1.2 kg
Depth Range
1–50 m
Latitude
37°S – 42°N
Trophic Level
2
Resilience
High
Vulnerability
21.00/100
Migration
Oceanodromous
Salinity
30–40 ppt

🔬 Taxonomy

🐟 Physical Description

Dorsal spines (total): 13; Dorsal soft rays (total): 10; Anal spines: 7; Anal soft rays: 9; Vertebrae: 13. Body olive green or brown above, silvery below; fish frequently with a dark patch below origin of lateral line. Adults become mottled when frightened. Slender, pungent, venomous spines. Preopercular angle 89°-95°. Lower half to 2/3 of cheeks commonly covered with weak, scattered scales. Midline of thorax between pelvic ridges. Differs from S. argenteus in details of coloration and less deeply forked tail .: short and / or deep; Cross section: compressed.

🌀 Behaviour

Behavioural data for Mottled spinefoot is currently being reviewed.

🦐 Diet

algae
aquatic plants
detritus

🥚 Reproduction

Size at Maturity
12.9cm TL

In Belau, ripe individuals form prespawning congregations of 30-60 individuals in shoal areas of inner reef flats; spawning occurs on the 4th or 5th day of the new moon; spawning sites are near reef edge. About 300,000 eggs/female at a single spawning. Individuals that spawn in consecutive yrs. & that 2+ yr. class fish could spawn more than once in a single season. Aug (Ref 1754) in Belau.

🌍 Habitat & Distribution

Marine; brackish; reef-associated; oceanodromous ; depth range 1 - 50 m . Tropical; 42°N - 37°S, 90°E - 171°E

🌿 Ecology

Zone Preferences
🌊 Marine 🌿 Brackish 🪸 Reef Associated
Migration
Oceanodromous
Trophic Level
2±0.1
🐠 Schooling
Food Items

filamentous algae, adults feed on leafy algae and seagrasses (Ref

📐 Morphometrics

Length–Weight Relationship: W = 0.01288 × L3.04 (TL)
Max TL
40cm
Max Weight
1,200g
Dorsal Spines
13
Dorsal Rays
10
Anal Spines
7
Anal Rays
9
Vertebrae
13

🌡️ Water Parameters & Tolerance

Salinity Range
30–40ppt

🛡️ Conservation Assessment

IUCN Category
Least Concern
Assessment Date
2015

📊 Population Risk & Fisheries

Population Resilience
High
Minimum doubling time
Fishing Vulnerability
21.00/100
Low vulnerability
Trophic Level
2
Omnivore / Planktivore
Body Shape
Short and / or deep
Climate Zone
Tropical
Latitude Range
42°N – 37°S
Described By
Houttuyn, 1782

⚠️ Venom Profile

Medical Warning: This species is venomous. Seek immediate medical attention if envenomated. Contact emergency services and follow first aid guidance below.
Venom Type
proteinaceous neurotoxin
Delivery
dorsal, anal, and pelvic fin spines
Potency
Severe
Mortality Risk
Low
Symptom Onset
5min
Duration
24.0hrs
Antivenom
✗ Not Available
Named Toxins
high-molecular-weight protein (Stonustoxin analogue) acetylcholine
Symptoms
  • immediate intense pain
  • swelling
  • erythema
  • occasional nausea and weakness
Affected Body Systems
peripheral nervous system cardiovascular
First Aid
Immerse affected area in hot water (45 C, tolerable) for 30-90 minutes to denature toxin. Do not apply ice.
Medical Treatment

Analgesia; wound care; tetanus prophylaxis; severe cases may require monitoring for systemic effects.

References: Compiled from Bhide (2018), Halstead et al. (1988) and family-specific envenomation literature

🎣 Angling Guide

Difficulty
Beginner
Fight Rating
strong pulls with head-shakes
Best Seasons
spring,summer,fall
Best Time
incoming tide, dawn and dusk
Line Weight
15-30
Rod Type
medium-heavy spinning
Hook Size
2/0-5/0
Catch & Release
✓ Recommended
Best Months
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Techniques
bottom fishing popping cork soft plastics live bait
Bait & Lures
live shrimp cut mullet soft plastic paddle-tails popping corks
Recommended Tackle
  • medium-heavy 7ft spinning rod
  • 30-50 lb braid
  • fluorocarbon leader
Where to Find Them
  • grass flats
  • oyster bars
  • marsh drains
  • deeper channel edges
Tips & Tricks
Popping cork technique attracts fish from distance. Fish moving tides.
Catch & Release Tips

Use barbless hooks, minimise air exposure, and revive fish head-first in current before release.

Regulations Summary

⚠️ Slot limits protect breeding-size fish. Verify daily bag limits.

🍽️ Edibility & Flavour

"Mottled spinefoot is an edible species."

✗ Not for Raw
✓ Fresh Indicators
  • Clear, bright eyes — cloudy eyes indicate age
  • Firm flesh that springs back when pressed
  • Fresh ocean smell, never strong or ammonia-like
  • Bright red or pink gills, not grey or brown
  • Shiny, moist skin with scales tightly attached
✗ Avoid If
  • Cloudy or sunken eyes
  • Strong fishy or ammonia odour
  • Soft, mushy flesh that doesn't spring back
  • Discoloured or dry flesh
Best Cooking Methods
Baking Grilling Pan-frying

⚡ Nutrition

Per 100g cooked - Source: USDA FoodData Central

Nutrient Amount
Protein 19.2 g
Omega-3 (total) 145 mg

🔬 Mercury Safety

Mercury data for Mottled spinefoot has not yet been assigned. Please consult FDA/EPA guidance for general seafood safety advice.

🌿 Sustainability

Best Choice
Healthy stocks, low impact
Good Alternative
Well-managed, minor concerns
Use Caution
Check sourcing and season
Avoid
Overfished or high impact
✓ Sustainable Choice

🔬 Full Nutritional Profile

Per 100g - Raw, per 100g - Source: USDA FoodData Central templates (generic fish average)

Proximate Composition
Energy125 kcal
Moisture75 %
Protein20 %
Total Fat4 %
Ash1.3 %
Fatty Acids (g)
Saturated Fat1 g
Monounsaturated Fat1.2 g
Polyunsaturated Fat1.5 g
Omega-3 Total1 g
EPA0.3 g
DHA0.5 g
Omega-6 Total0.3 g
Key Minerals & Vitamins
Calcium20 mg
Iron0.7 mg
Magnesium30 mg
Phosphorus220 mg
Potassium380 mg
Sodium55 mg
Zinc0.5 mg
Selenium32 µg
Vitamin B122 µg

📊 Population Dynamics

Year Region Index Notes
- - -

👥 Community & Contribute

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