The breeding behaviour (territorial behaviour, male quality, movement and mating success) of male and female Weddell seals in relation to reproductive success during the breeding season

The breeding behaviour of the Weddell seal, Leptonychotes weddelli at the Turtle Rock colony in McMurdo Sound was studied over four breeding seasons. The aim was to quantify the male and female behaviour during the breeding season and to relate the characteristics of individuals to their mating success. The territorial behaviour and individual male quality was determined by capturing animals, tagging, weighing, marking (with hair dye), measuring standard morphometric information (length, girth, etc), attaching archival heart rate loggers and gluing acoustic transmitters to the dorsal surface of the animal, which records parameters like depth, swim speed, water temperature and location. At the end of the season, males were recaptured and change in body composition and mass was recorded. Females were captured and had transmitters were attached to them as well. The movement of the animals was recorded by placing an array of four hydrophones under the ice around the colony. The position of each animal was automatically logged when it was underwater at intervals of between 20-60 seconds. Body composition of males to which pingers were attached was determined by measuring total body water using hydrogen isotope dilution. The cortisol response to handling was analysed over the course of handling. The mating success of males was determined by analysis of skin samples collected from males and from mother-pup pairs at several colonies (Turtle Rock, Hutton Cliffs, Turks Head, Little and Big Razorback Islands, Inaccessible Island, Tent Island and the south base of the Erebus Glacier Tongue) as breeding females were found to move between colonies between years. By examining how individual quality (rate of energetic expenditure, changes in condition and behaviour) relates to paternity microsatellite genetic markers were measured and how male seals compete for access to mates was determined. A >125 point grid was drilled over the study area of Turtle Rock and depth recorders were used to map the under ice topography.