Reproductive resilience of ice‐dependent <scp>A</scp>ntarctic silverfish in a rapidly changing system along the <scp>W</scp>estern <scp>A</scp>ntarctic <scp>P</scp>eninsula

• Published in: Marine Ecology
• Main Authors: La Mesa, Mario, Riginella, Emilio, Mazzoldi, Carlotta, Ashford, Julian
• Other Authors: United States National Science Foundation, Programma Nazionale di Ricerca in Antartide
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2014
• Subjects: Ecology; Aquatic Science; Ecology, Evolution, Behavior and Systematics; Joinville; Antarc*; Antarctica; Sea ice
• Online Access: http://dx.doi.org/10.1111/maec.12140; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmaec.12140; https://onlinelibrary.wiley.com/doi/pdf/10.1111/maec.12140

Abstract The W estern A ntarctic P eninsula ( wAP ) is globally one of the systems most heavily impacted by climate change, notably steep declines in sea ice extent. In forage species, reproductive resilience to change is particularly important because population fluctuations are rapidly communicated through the system via trophic interactions. The reproductive traits of the ice‐dependent forage species A ntarctic silverfish ( P leuragramma antarctica ) from different areas along the wAP and at the tip of the A ntarctic P eninsula were investigated through macroscopic and histological analyses of gonads, with the aim to assess its reproductive potential and to test for spatial differences in fecundity and spawning season. Fish samples were collected in late summer off C harcot I sland, in M arguerite B ay and off J oinville I sland; no fish were caught in the central w AP . Samples from C harcot I sland and M arguerite B ay consisted of adults in developing gonad stage, whereas those from Joinville consisted almost exclusively of juveniles. Mean GSI was relatively low (2–3%) and similar in both sexes, as specimens were still far from being actively reproducing. Developing females exhibited two discrete, though partially overlapping modes of oocytes of different size, with vitellogenic oocytes measuring 0.5–1.0 mm. Absolute and relative fecundity ranged between 3000 and 12,000 eggs per female and between 80 and 190 eggs·g −1 , with a strong relationship between absolute fecundity and body size. These results were consistent with a single population at C harcot I sland and M arguerite B ay and indicated substantial reproductive potential, which may mitigate population isolation and reductions in habitat availability but cannot ultimately offset catastrophic loss of spawning habitat linked to sea‐ice retreat.