Tsurizukan

Fish

Barred Knifejaw イシダイ

Oplegnathus fasciatus ・ イシダイ科

Barred Knifejaw (Oplegnathus fasciatus)
Photo: M.O. Stevens / CC BY-SA 3.0 — source

Catch season

The classic big fish of the rocky shore. Juveniles, called shimadai, turn up on piers, but the large ones belong to serious rock fishing.

About

A rocky-reef fish wearing seven bold black bars on a pale body, found along coasts washed by warm currents. Its upper and lower teeth are fused into a beak strong enough to crush shellfish and sea urchins. Old males lose the bars and darken around the mouth, earning the name kuchiguro, black-mouth. The related spotted knifejaw is covered in fine dark speckles instead of bars.

Basics

Scientific name
Oplegnathus fasciatus
Family
イシダイ科
Japanese name
イシダイ
Kana
いしだい
Also called
シマダイ, サンバソウ
Waters
Sea of Japan, Southern Pacific coast, East China Sea & western Kyushu
Size
40 cm (max 80 cm)
Time of day
Dawn, Daytime
Depth (tana)
On the bottom, and the rougher the ground the bigger the fish: submerged rock edges and the white water of breaking waves.
Local names
サンバソウ, クチグロ

How to catch it

The classic rocky-shore bottom quarry. Anglers use sea urchin or turban snail on a wire leader with a stout dedicated rod and conventional reel. The spring spawning run and the autumn feeding spree are the peak times.

Surf casting from a Rocky shore

A bottom fishery: place the rig against submerged rock, set the rod in a holder, and wait. The urchins and shellfish used as bait are usually covered by fishery rights, so buy them or obtain permission.

Waters: Sea of Japan, Southern Pacific coast, Seto Inland Sea, East China Sea & western Kyushu

Float fishing from a Breakwater / Pier

The boldly striped juveniles, called shimadai, come to the piers in summer. Even a small one has powerful teeth, so keep your fingers out when unhooking it.

Waters: Sea of Japan, Southern Pacific coast, Seto Inland Sea, East China Sea & western Kyushu

Kit for this fish

Surf casting kit ・ Kit total ¥22,000–60,000

You are swinging a heavy sinker, so checking behind you and keeping distance from others is the core of safety here. The cap and glasses are included as eye protection.

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Handle with care

This fish is dangerous to handle bare-handed.

Sharp teeth Moderate ・ Where: 口(癒合した強い歯板)

Its teeth are fused into plates strong enough to crush sea urchins and turban shells, and a finger placed in its mouth can be injured to the bone. Always unhook it with pliers.

Dangerous fish and animals — what to do when you are stung or bitten

Eating

Eating quality 5/5 ★★★★★

Sashimi or arai. A firm white flesh; large fish command high prices.

Best eating: July–October

Rules

The sea urchins and shellfish used as bait are usually covered by fishery rights, and taking them yourself can be an offence. Buy your bait, or get permission from the local cooperative.

Yugyoken and fishing rights — the sea and the rivers are governed differently

This article organises general information and is not legal advice. Rules differ by municipality and by fishery cooperative, and they change. Always check the current rules for where you are going.

Other fish taken the same way

Other fish from the same kind of place