Recruitment Variability in North Atlantic Cod and Match-Mismatch Dynamics

Background Fisheries exploitation, habitat destruction, and climate are important drivers of variability in recruitment success. Understanding variability in recruitment can reveal mechanisms behind widespread decline in the abundance of key species in marine and terrestrial ecosystems. For fish populations, the match-mismatch theory hypothesizes that successful recruitment is a function of the timing and duration of larval fish abundance and prey availability. However, the underlying mechanisms of match-mismatch dynamics and the factors driving spatial differences between high and low recruitment remain poorly understood. Methodology/Principal Findings We used empirical observations of larval fish abundance, a mechanistic individual-based model, and a reanalysis of ocean temperature data from 1960 to 2002 to estimate the survival of larval cod (Gadus morhua). From the model, we quantified how survival rates changed during the warmest and coldest years at four important cod spawning sites in the North Atlantic. The modeled difference in survival probability was not large for any given month between cold or warm years. However, the cumulative effect of higher growth rates and survival through the entire spawning season in warm years was substantial with 308%, 385%, 154%, and 175% increases in survival for Georges Bank, Iceland, North Sea, and Lofoten cod stocks, respectively. We also found that the importance of match-mismatch dynamics generally increased with latitude. Conclusions/Significance Our analyses indicate that a key factor for enhancing survival is the duration of the overlap between larval and prey abundance and not the actual timing of the peak abundance. During warm years, the duration of the overlap between larval fish and their prey is prolonged due to an early onset of the spring bloom. This prolonged season enhances cumulative growth and survival, leading to a greater number of large individuals with enhanced potential for survival to recruitment

The region that isn't: China, Russia and the failure of regional integration in Central Asia

The failure of regionalism in Central Asia is a puzzle. Whereas almost all world regions have seen a rise of regional organisations since the end of the Cold War, attempts to establish durable regional cooperation among Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan proofed unsuccessful. Although some of the Central Asian countries participate in wider regional organisations like the Eurasian Economic Union (EAEU) and the Shanghai Cooperation Organisation (SCO), the genuine Central Asian Cooperation Organisation (CACO) was dissolved in 2005. Given the cultural, economic and political similarities between the five Central Asian countries, this lack of a regional organisation is surprising. In contrast to previous work, this paper argues that the failure of regionalism in Central Asia is not so much due to domestic political factors, but more to the extra-regional economic dependence of the regional economies and the impact of external powers within Central Asia. Challenged by the rise of China, Russia uses the EAEU in order to preserve its hegemonic influence over the former Soviet Republics. By joining the Russian dominated EAEU, Central Asia’s regional power Kazakhstan enjoys economic benefits which outweigh the potential gains of Central Asian cooperation within CACO by far. Consequently, Kazakhstan follows its extra-regional interests in closer cooperation with Russia at the cost of regional cooperation with its Central Asian neighbours. As a result, the Central Asian countries are unable to build up a unified regional block in relation to extra-regional powers like China or Russia