Ironically – considering the frequency with which school children use it for exactly this purpose – the Oxford English Dictionary never set out to specify “correct” spelling.
For “mackerel”, the second edition in 1989 listed 19 alternative spellings. The unearthing of sources never ends, though, so the third edition revised entry in 2002 listed no fewer than thirty: maccarel, mackaral, mackarel, mackarell, mackerel, mackarell, mackeril, mackreel, mackrel, mackril, macquerel, macquerell, macrel, macrell, macrelle, macril, macrill, makarell, makcaral, makerel, makerell, makerelle, makral, makrall, makreill, makrel, makrell, makyrelle, maquerel, and maycril.
As lexicographers, the editors would never declare these alternatives to be wrong: misspellings. They do not wish to declare their choice of spelling for the headword, mackerel, to be “correct”. They emphasize that they examine the evidence and choose “the most common current spelling.”
A new entry as of December 2003 memorialized “nuclar”: “= nuclear, (adjective, in various senses).”James Gleick – The Information
All spellings are made up, and exist as dynamic parts of the complex adaptive system of language. Conclusion: we waste too much attention on typos.