A recent publication by NIOZ ecologists Mark Rademaker, Myron Peck, and Anieke van Leeuwen in the journal Global Change Biology has revealed that young herring are arriving in the Wadden Sea earlier and earlier in the spring due to changing climate conditions. This finding was made possible by the consistent and precise measurement of fish populations in the Marsdiep area between Den Helder and Texel using a standard fyke since 1960. The researchers noted that the peak number of young herring entering the Wadden Sea has shifted at least two weeks earlier since 1982.
The key to identifying this change in herring migration patterns lies in the extremely consistent measurements taken by NIOZ over the past 60 years. By using the same fyke to sample fish populations in the same location year after year, the researchers were able to accurately track long-term trends in the timing of herring arrival in the Wadden Sea. This level of consistency is essential when studying species that move in large schools, as daily fluctuations in fish numbers can skew the data if measurements are not taken consistently.
The research conducted with the ‘NIOZ fyke’ is considered unique in the world, as most other monitoring programs do not consistently measure fish populations at the same location and frequency. Rademaker emphasized the importance of carrying out measurements in the same spot continuously to reliably detect long-term changes in fish behavior. By comparing the NIOZ data with other monitoring programs that sample less frequently and at varying locations, Rademaker found that changes in herring migration timing did not show up, underscoring the significance of consistent measurements.
The study on the rhythm of young herring in the Wadden Sea will be featured in Rademaker’s upcoming dissertation at Wageningen University. In addition to analyzing the influence of climate on herring populations, Rademaker also examined long-term sampling of benthic life in the Wadden Sea and measurements of deep-sea squid near the Azores. His dissertation highlights the importance of combining statistical analysis with field experiments and measurements to ensure research findings are meaningful. Rademaker cautions against relying solely on statistics and emphasizes the need for a solid theory to explain trends observed in large datasets.
Overall, the research conducted by NIOZ ecologists demonstrates the importance of long-term, consistent monitoring in tracking changes in marine ecosystems. By using the unique data collected with the ‘NIOZ fyke’, researchers were able to identify shifts in herring migration patterns in response to climate change. This study not only contributes valuable insights into the impacts of climate change on marine species but also highlights the necessity of integrating field work, experimentation, and theory to produce meaningful scientific findings.
