Territorial behaviour of the north temperate labrid, Tautogolabrus adspersus

Abstract

A study of territorial behaviour of the cunner, Tautogolabrus adspersus, was carried out in Conception Bay, Newfoundland, in 1977 and 1978. Cunners that overwinter in a torpid state were active only from May to late October of both years. Large males established territories prior to the midsummer spawning season and territories were defended throughout and after that season. Territory size ranged from 16.1 to 74.3 m2 on rocky substrate at depths of 0.7 to 13 m and did not vary significantly with either the size of the resident fish or the degree of intraspecific aggression it exhibited. Nonterritorial males were generally smaller than territorial males and were vigorously excluded from their territories. Only territorial males exhibited interspecific aggression, which was most frequent toward Pholis gunnellus. Territorial females were present in the peripheral areas of some males' territories and were aggressive toward other females. Tagging indicated that most males and some females defend the same territory from year to year, and that territory size remains relatively constant. The proportions of territorial and nonterritorial fish, of either sex, in the population are unknown. The primary function of territorial behaviour in T. adspersus may be the provision of a spawning site from which potential rivals are excluded.