Reproductive ecology of the circumpolar Antarctic nemertean Parborlasia corrugatus: No evidence for inter-annual variation

摘要: Waters around the Antarctic Peninsula are experiencing one of fastest rates warming seen anywhere on Earth in sea recent times. Species inhabiting nearshore seabed sites Antarctica have a long history near freezing temperatures and poor physiological capacities to cope with change. Reproductive success is vital characteristic species survival evaluation how reproductive processes vary time key identifying vulnerable evaluating effects ocean warming. The long-term gametogenic development nemertean Parborlasia corrugatus (McIntosh, 1876) was analysed from monthly samples collected between July 1997 November 2000 shallow water site adjacent British Survey Rothera Research Station (Western Peninsula). Spermatogenesis, oocyte size condition described for each month using histological image analysis techniques. Male female varied seasonally, reduction proportion large oocytes mature sperm gonad during late austral summer (December–March). We identify three characteristics ecology P. (1) timing reproduction consistent year synchronous males females (2) oogenesis progressed over discrete 15–16 period single generation ovary most stages (3) notable differences were not apparent year. The majority studies marine invertebrates at high latitudes, exception or two species, revealed that 18–24 months required gametogenesis compared 6–12 temperate there extreme inter-annual variation output. differs this requiring only 15 gametogenesis, has little no years. This may be because its predatory lifestyle coupling timing, larval abundance nutrition phytoplankton productivity much less than previously studied herbivores omnivores. However, settlement peak juvenile does suggest seasonal through nemertean's ecology.