Isidore of Seville [7th century CE] (Etymologies, Book 12, 6:39): The allec is a small fish suitable for pickled fish sauce (salsamentum), whence it is named. - [Barney, Lewis, et. al. translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Fish 7.5): Allecia are sea fish, as he says [i.e. Liber rerum], living in the western sea, which is the ocean between Britain and Germany. The season at which these fish are usually caught is said to be the best in almost every kind of sea fish. For every kind of sea fish generally has its season, and at another season it is not good. The best catch of allecia is around the month of August or around September. Its season can last until December, but this is rare because of time constraints. This fish is very small, but when it is freshly caught, it makes the most delicious food. When salted it can last longer than other fish used by humans. There is sweetness in its head, which is hardly ever spoiled by the bitterness of salt. Almost all fish live only in water, and can only live in water, and as soon as it is taken into the air it expires, and there is no delay between the contact of the air and its death. Its eyes shine in the night in the sea like a light, but the power of these dies with the fish itself. Wherever in the sea they see a light upon the waters, they come in flocks, and by this artifice are attracted to the nets. At the said times, as if ready to be taken into use by men, they are brought down by divine gift. But in winter they are hidden in secret in the sea until the appointed time, and this around Germany. Allecia are the best in the country of Scotland, but the worst towards Germany. - [Badke translation/paraphrase]