Abstract
Shallow estuaries, bays, and lagoons are generally considered hot spots of ocean productivity that often adjust rapidly to seasonal variations in atmospheric temperatures. During spring when biological reproductive processes begin in the temperate zones, regional climate variability can be immense and uncovering a non-linear biological response, such as fish recruitment to changing temperature regimes might be challenging. Using herring as a paradigm for a response of coastal spring productivity to regional climate drivers, we demonstrated how the annual timing of spawning periods can significantly affect the reproductive success of spring-spawning herring (Clupea harengus) in the western Baltic Sea. An investigation of spawning phenology in consecutive years indicated a temperature threshold range of 3.5–4.5°C triggering initial spawning in the coastal zone. Based on this finding, we analyzed the timing of larval hatching peaks, larval survival and recruitment to the adult population relative to multi-decadal time-series of seasonal sea-surface temperatures. The results revealed that the late seasonal onset of cold periods the corresponding elongation of the period where larvae hatch from the eggs and early larval hatching peaks significantly reduced larval production in a coastal nursery area and finally lead to a reduced abundance of juveniles in the entire distribution area. Using a combination of field research and time series analysis, we presented precedence for shifting regional winter regimes providing a present-day stressor to reproductive capacity of a central component of the coastal food web.
Highlights
There is increasing evidence that spring temperatures are rising in the temperate zones (Schwartz et al, 2006)
Earlier studies reveal a significant influence on variations in large-scale climate regimes on the reproductive success of fishes, on species that spawn all at once in a single sequence determined by a particular season, such as springspawning herring in the Baltic Sea (Cardinale et al, 2009; Gröger et al, 2014)
Our results demonstrate that fish reproductive success in temperate coastal zones is subject to particular regional characteristics of seasonal temperature regimes relative to species- or population-specific temperature thresholds for reproduction phenology
Summary
There is increasing evidence that spring temperatures are rising in the temperate zones (Schwartz et al, 2006). Bates et al (2018) suggested that ecologists include regional climate regimes in their studies rather than relating changes in biota to average global warming. This criticism seems well justified considering that species phenology is often subjected to regional climate regimes and inshore, coastal systems are globally known as hot spots of ocean productivity and biodiversity (Cloern et al, 2014; Simcock, 2017). Shorter winters and steep spring temperature progressions might already affect these systems greatly, potentially influencing keystone species of coastal food webs with determined seasonal timing of reproduction processes
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
