tangfish

noun

1. (UK, dialectal, no-plural)A common or harbour seal (Phoca vitulina).

   “The coasts of Shetland swarm with the smaller seals, or Tangfish, so named from being supposed to live among the Tang, or larger fuci that grow near the shore.”

   “a noted retreat of seals or selkies, or tangfish, as they are vernacularly called in Zetland”

   “On the rugged shores of Orkney there are two kinds of seal – the common seal or 'tangfish' (seaweed fish) of the Shetlands […] and the great grey seal”