Coastal 1C: what light survives

Coastal 1C: the light that survives here peaks at 500 nm, Secchi depth about 6.8 m. Which lure colour stands out, computed rather than charted.

Light that survives best here: 500 nm

Secchi ≈ 6.8 m

What this water lets through

K_d is the diffuse attenuation of the light coming down; c is the beam attenuation along the line of sight. Confusing the two is the classic error in this field.

λ	K_d	c	1 m	5 m
400 nm	0.240	1.369	78.7%	30.12%
430 nm	0.212	1.263	80.9%	34.69%
460 nm	0.189	1.173	82.8%	38.88%
490 nm	0.167	1.093	84.6%	43.38%
520 nm	0.164	1.034	84.9%	44.12%
550 nm	0.180	0.996	83.5%	40.66%
580 nm	0.227	0.988	79.7%	32.18%
610 nm	0.392	1.084	67.6%	14.08%
640 nm	0.467	1.110	62.7%	9.69%
670 nm	0.586	1.179	55.6%	5.33%
700 nm	0.802	1.332	44.8%	1.81%

K_d is the diffuse attenuation of the light coming down; c is the beam attenuation along the line of sight. Confusing the two is the classic error in this field. Method and sources

Lure table

Ranked by how much each colour stands out to a Atlantic salmon in these conditions.

	Colour	Contrast	Seen from
1	White	97	5.3 m	Buy now
2	Sexy shad	93	5.3 m	Buy now
3	Silver holographic Metallic finish	93	5.2 m	Buy now
4	Glow Glow finish — not modelled	93	5.1 m	Buy now
5	Chartreuse / white Fluorescent finish	91	5.3 m	Buy now
6	Bone	91	5.0 m	Buy now
7	Chrome Metallic finish	90	5.0 m	Buy now
8	Pink / white Fluorescent finish	88	5.3 m	Buy now
Stands out least
	Watermelon red flake	34	2.5 m
	Brown	30	2.2 m
	Red craw	26	1.9 m
	Red	26	1.9 m

Contrast quoted at 1.0 m viewing distance. · Light that survives best here: 500 nm

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UV cannot be shown — This species has a UV cone, and a phone screen cannot emit ultraviolet. The UV channel is drawn in a declared false colour. Note also that UV is absorbed fast underwater and vanishes within centimetres in tannic water.

Target species

Atlantic salmon Salmo salar European seabass Dicentrarchus labrax Gilthead seabream Sparus aurata Striped bass Morone saxatilis Atlantic cod Gadus morhua Pollock Pollachius pollachius Turbot Scophthalmus maximus Bonefish Albula vulpes Tarpon Megalops atlanticus Great barracuda Sphyraena barracuda Meagre Argyrosomus regius Common dentex Dentex dentex Atlantic mackerel Scomber scombrus Yellowtail kingfish Seriola lalandi Bluefish Pomatomus saltatrix

Open the calculator

Gear this page implies

A Secchi disc See on Amazon
Lower it until it disappears and read the depth. That single number tells you which water type above is yours — it is the one optical measurement anybody can take.

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