Linking fisheries, trophic interactions and climate: threshold dynamics drive herring Clupea harengus growth in the central Baltic Sea

Marine Ecology Progress Series

Valerio Bartolino¹  Michele Casini¹  Georgs Kornilovs¹  Juan Carlos Molinero¹ 

关键词: Condition;    Weight-at-age;    WAA;    Ecological threshold;    Inter-specific density-dependence;    Hydro-climate;    Herring;    Sprat;    Ecosystem-based fisheries management;    Alternative dynamics;   

DOI  :  10.3354/meps08592

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: How multiple stressors influence fish stock dynamics is a crucial question in ecology in general and in fisheries science in particular. Using time-series covering a 30 yr period, we show that the body growth of the central Baltic Sea herring Clupea harengus, both in terms of condition and weight-at-age (WAA), has shifted from being mainly driven by hydro-climatic forces to an inter-specific density-dependent control. The shift in the mechanisms of regulation of herring growth is triggered by the abundance of sprat, the main food competitor for herring. Abundances of sprat above the threshold of ~18 × 10¹⁰ ind. decouple herring growth from hydro-climatic factors (i.e. salinity), and become the main driver of herring growth variations. At high sprat densities, herring growth is considerably lower than at low sprat levels, regardless of the salinity conditions, indicative of hysteresis in the response of herring growth to salinity changes. The threshold dynamic accurately explains the changes in herring growth during the past 3 decades and in turn contributes to elucidate the parallel drastic drop in herring spawning stock biomass. Studying the interplay between different stressors can provide fundamental information for the management of exploited resources. The management of the central Baltic herring stock should be adaptive and take into consideration the dual response of herring growth to hydro-climatic forces and food-web structure for a sound ecosystem approach to fisheries.

【 授权许可】

Unknown