Other names for blue mackerel: English mackerel, Tawatawa, slimy mackerel
The blue mackerel is one of the smallest members of the tuna family. A big specimen can reach 55cm but most fish are between 30 and 45cm in length. It is a slender fish not unlike the kahawai at first glance.
The upper sides of the blue mackerel are blue-green broken up by a darker zigzag pattern of lines and spots on the upper half of the sides and upper body. The undersides are silver white. There is a single row of sharp pointed teeth in each jaw. There is a keel on either side of the base of the tail. The round body is covered in scales.
Blue mackerel eat whale feed or krill (shrimps), small bait fish such as anchovies and sprats, and squid. These prey animals are seasonally and locally abundant. Blue mackerel schools are pelagic hunters that migrate long distances and so can be plentiful or absent dependant on the availability of prey.
The main areas for blue mackerel off New Zealand are around the North Island and upper South Island mostly in deeper water over the outer continental shelf. As such they are caught by boat anglers only. The best areas are: in the South Taranaki Bight, east of North Cape, in the Bay of Plenty, and offshore north of Kaikoura. They are often found in mixed schools together with kahawai and jack mackerel. Blue mackerel are also found off Otago and Banks Peninsula.
Like all tunas and mackerels, they will readily take a lure. Most of the blue mackerel taken by sports anglers are caught on jigs and flasher rigs. They are strong fighters, on rod and line, pulling much like a kahawai when hooked deep. When a school is located on the sounder or found feeding on the surface, drop your jig and flasher straight down until the fish strike. A word of warning is needed here. When they are on the bite you can get as many mackerel on your flasher rig as you have hooks!
Blue mackerel is an oily fish with high-fat content. The flesh is dark but lightens when cooked. The high oil content makes it is an excellent fish for smoking. It is otherwise not highly regarded in New Zealand as a table fish. Blue mackerel do not keep well and so must be gutted and frozen quickly after capture. They make excellent cut baits for groper and trumpeter.
Trolling will work well. As will small cubes of cut bait. If you locate a surface school you can have great fun on the light spinning gear of say 4 or 6 lb monofilament and a light rod. As to lure they will take just about anything fired into, or near, the school. Small jigs (40g), bullet heads, and hex wobblers all work well. They can also be brought up and held near the boat with a steady stream of berley so you can have a go at them with your fly rod. A sinking line and a deceiver pattern are a good place to start. A deceiver that “matches the hatch” is also a good idea.