Dataset for: Spawning fish maintain trophic synchrony across time and space beyond thermal drivers ...

• Main Authors: Opdal, Anders Frugård, Wright, Peter J., Blom, Geir, Höffle, Hannes, Lindemann, Christian, Kjesbu, Olav S.
• Format: Dataset
• Language: English
• Published: Dryad 2023
• Subjects: FOS Biological sciences; Climate change; Phenology; Northeast Arctic cod; Norway; Spawning; Arctic; Arctic cod; Gadus morhua; Phytoplankton
• Online Access: https://dx.doi.org/10.5061/dryad.12jm63z2r; https://datadryad.org/stash/dataset/doi:10.5061/dryad.12jm63z2r

Increasing ocean temperature will speed up physiological rates of ectotherms. In fish, this is suggested to cause earlier spawning, due to faster oocyte growth rates, causing spawning time to potentially become decoupled to the timing of the offspring’s food resources. A phenomenom referred to as trophic asynchrony. We used biological data, including body length, otolith information, and gonad developmental stages collected from > 125,000 individual Northeast Arctic cod (Gadus morhua) sampled between 59 and 73 °N in 1980-2019. Combined with experimental data of oocyte growth rates, our analysis shows that cod spawned progressively earlier by about a week per decade, partly due to ocean warming. It also appears that spawning times vary by more than 40 days, depending on year and spawning location. The significant plasticity in spawning time seems to be fine-tuned to the local phytoplankton spring bloom phenology. This ability to partly overcome thermal drivers could allow individuals to phenologically ... : ## Variable explanations | Name | Description | | ---- | ----------- | | Year | year of sample | | DOY | day of year. DOY=1 is Jan 1st | | Sex | sex | | Age | age, years, classified from otolith reading | | Length | body length, cm | | Stage | gonad stage classified by visual inspection | | Lat | latitude, decimal degrees North rounded to nearest 0.001 degrees | | Lon | longitude, decimal degrees East rounded to nearest 0.001 degrees | | Y-UTM | latitudinal UTM coordinates (zone 33) rounded to nearest 100 m | | X-UTM | longitudinal UTM coordinates (zone 33),rounded to nearest 100 m | | Gear | type of fishing gear used | | Sampling | sampling program/scheme | NOTE: sampling locations are rounded to nearest 0.001 degree, or 100 m as per recommendations for Category 4 species (Chapman, 2020). Chapman AD (2020) Current Best Practices for Generalizing Sensitive Species Occurrence Data. Copenhagen: GBIF Secretariat. https://doi.org/10.15468/doc-5jp4-5g10. ...