Slave to the rhythm: how large-scale climate cycles trigger herring (Clupea harengus) regeneration in the North Sea

Abstract

Gröger, J. P., Kruse, G. H., and Rohlf, N. 2010. Slave to the rhythm: how large-scale climate cycles trigger herring (Clupea harengus) regeneration in the North Sea. – ICES Journal of Marine Science, 67: 454–465. Understanding the causes of variability in the recruitment of marine fish stocks has been the “holy grail” of fisheries scientists for more than 100 years. Currently, debate is ongoing about the functionality and performance of traditional stock–recruitment functions used during stock assessments. Additionally, the European Commission requires European fishery scientists to apply the ecosystem approach to fisheries in part by integrating environmental knowledge into stock assessments and forecasts. Motivated to understand better the recent years of reproductive failures of commercially valuable North Sea herring, we studied large-scale climate changes in the North Atlantic Ocean and their potential effects on stock regeneration. Applying traffic light plots and time-series (TS) analyses, it was possible not only to explain the most recent reproductive failures, but also to reconstruct the full TS of recruitment from climate cycles, indexed by the North Atlantic Oscillation and the Atlantic Multidecadal Oscillation. A prognostic model was developed to provide predictions of herring stock changes several years in advance, allowing recruitment forecasts to be incorporated easily into risk assessments and management strategy evaluations, to promote a sustainable herring fishery in the North Sea. Insights gained from the analysis permit reinterpretation of the sharp decline in the North Sea herring stocks in the 1970s.

Parallel adaptive evolution of geographically distant herring populations on both sides of the North Atlantic Ocean

“…stocks have been described based on morphology and life history traits such as spawning time and location (13)(14)(15). Populations are known to spawn in different seasons, with some spawning in the spring, others in the autumn, and still others at intermediate times.…”

Spatial analysis of North Sea cod recruitment: concurrent effects of changes in spawning stock biomass, temperature and herring abundance

“…However, the young are not spread by random all over the NS (e.g. Heath et al 2008, Gröger et al 2010.…”

“…Thus, Wright et al (2006) argued that the NS cod forms a metapopulation, and we would expect cod recruitment to depend on the abundance of spawners in an upstream area. In the case of NS herring, it has 3 or 4 spawning components in separate locations on the west side of the NS; spawning starts in the north in August and ends in January in the south (Daan et al 1990, Gröger et al 2010. The herring juveniles of several stocks mix (Ruzzante et al 2006, Gröger et al 2010, and as they grow, they gradually move into deeper water; by Age 1 they are spread over the entire southern NS.…”

“…In the case of NS herring, it has 3 or 4 spawning components in separate locations on the west side of the NS; spawning starts in the north in August and ends in January in the south (Daan et al 1990, Gröger et al 2010. The herring juveniles of several stocks mix (Ruzzante et al 2006, Gröger et al 2010, and as they grow, they gradually move into deeper water; by Age 1 they are spread over the entire southern NS. Thus, for herring, it seems that the most correct assumption is that spawners contribute to recruitment anywhere in the NS (i.e.…”

Land- und Forstwirtschaft, Fischerei

“…Viele wissenschaftliche Studien zeigen den Zusammenhang zwischen der Rekrutierung und der Größe der kommerziellen Fänge unter den klimatischen Bedingungen für Arten wie z. B. Kabeljau (Brander und Mohn 2004;Cook und Heath 2005;O'Brien et al 2000), Scholle (Brunel und Boucher 2007), Hering (Nash und Dickey-Collas 2005), Makrele (Jansen und Gislason 2011) und Wolfsbarsch (Pawson 1992 (Alheit et al 2012;Gröger et al 2010). Ein Großteil solcher Studien für die Nordsee beschäftigte sich mit dem Kabeljau und zeigte, obwohl regional unterschiedlich (Planque und Frédou 1999), den negativen Einfluss der Erwärmung für diese kommerziell wichtige Art (O'Brien et al 2000;Beaugrand et al 2003;Drinkwater 2005;Heath und Brander 2001).…”