Selected aspects of the biology of the radiated shanny, Ulvaria Subbifurcata (Storer) 1839 (Pisces: Stichaeidae)

Abstract

Collections of Ulvaria subbifurcata were made by diving at several locations on the Avalon Peninsula. -- The diet of fish less than 55 mm total length comprised mainly copepods; larger fish, nereids. Polynoids and amphipods were eaten by fish of all sizes. These major food items were eaten during all seasons. -- Tagging studies showed that U. subbifurcata has restricted movements and will home to the capture site. Larger (> 6 cm total length) fish are nocturnal; smaller fish diurnal. Activity decreased in fish of all sizes during the winter. -- Spawning occurred in May at 4 C with fish first spawning at age three to five years. No secondary sex characters were noted. During each breeding season females spawned once, producing a demersal egg mass (mean - 2706 eggs). Males spawned up to four times and subsequently tended the egg mass (or masses). Incubation lasted 35 - 40 days. At hatching (6 - 9 C) larvae (mean - 6.58 mm total length) were positively phototropic. Young-of-the-year settled on bottom by August. -- Age determination by scales was validated by the Petersen method. Few fish exceeded an age of seven years. Theoretical Lₒₒ calculated by a Walford line was 130 mm.