It is becoming even clearer that, over longer time-scales, marine ecosystems function as non-linear complex adaptive systems. This means the potential consequences of global change become more diffused and obscured within a maze of possibilities.
In this article, Bakun attempts to route one pathway to a type of potentially more robust (albeit still speculative) conceptual synthesis, using the key case of anchovies and sardines as a model. In particular, the anchovy–sardine pair coexists over an exceptionally wide range of regional habitat configurations and physical dynamics, embodying a rich array of material for comparative analyses.
Expressly, the anchovy emerges as an efficient specialist that is adapted to rapidly increase in abundance under relatively steady, highly productive conditions. In contrast, the sardine's oceanic-based adaptations equip it to deal with intermittent episodes of poorly productive conditions and to take advantage of the reduced predation pressure on their offspring at early life stages. Based on the overall synthesis, the nimble, wide-ranging, actively opportunistic sardine appears to be well-equipped to deal with climate-related disruptions and dislocations and even to profit from resulting adverse effects on predators and competitors.
Global-scale multispecies population synchronies from the 1970s to mid-1980s suggest that a variety of different species types might be flagged for investigation as perhaps embodying similar "active opportunist" attributes. If so, events and anecdotes might, as global changes occur, begin to be viewed within a developing universal framework – one which could support the transfer of experience and predictive foresight across different species groups and regional ecosystems.
Children transport sea mullets (Mugil cephalus) in a northern Peruvian fishing port; © Dr. Kenny Broad, University of Miami.