Occurrence of two-year cyclicity, "saw-blade fluctuation", in vendace populations in Finland
Huusko Ari; Marjomäki Timo J.; Huuskonen Hannu; Auvinen Heikki; Jurvelius Juha; Hyvärinen Pekka; Viljanen Markku; Sarvala Jouko; Karjalainen Juha; Valkeajärvi Pentti; Helminen Harri
Occurrence of two-year cyclicity, "saw-blade fluctuation", in vendace populations in Finland
Huusko Ari
Marjomäki Timo J.
Huuskonen Hannu
Auvinen Heikki
Jurvelius Juha
Hyvärinen Pekka
Viljanen Markku
Sarvala Jouko
Karjalainen Juha
Valkeajärvi Pentti
Helminen Harri
FINNISH ZOOLOGICAL BOTANICAL PUBLISHING BOARD
Julkaisun pysyvä osoite on:
https://urn.fi/URN:NBN:fi-fe2021093048577
https://urn.fi/URN:NBN:fi-fe2021093048577
Tiivistelmä
The tendency towards two-year cyclicity is considered typical of many Fennoscandian vendace populations, especially in fluctuation of recruitment, based on time series of individual lakes. We used two robust indicators to identify and quantify two-year cycles in vendace population proxy time series at different life-stages - spawning stock biomass (SB), density of newly hatched larvae (LD) and recruitment (REC) - from 22 Finnish lakes. Then we applied Fisher's meta-analytical test to assess the adequacy of the evidence to support the hypothesis that vendace population dynamics include two-year cyclicity. The results supported this hypothesis for REC but not for SB or LD. Yet. the indicators and test are conservative and time-series of SB and LD are shorter than those for REC. The appearance of cycles in REC is associated with high post-recruitment mortality, consequently practically only one spawning per cohort. Cycles may be typical for the recovery period from low abundance period also. Still, some populations with moderate post-REC mortality and non-cyclic SB abundance exhibited cycles in REC. Such dynamics presuppose the existence of more complex regulation based on the interaction of different life stages.
Kokoelmat
- Rinnakkaistallenteet [19207]