Variation in consumer pressure along 2500 km in a major upwelling system: crab predators are more important at higher latitudes
Date
2019-10-10Author
Musrri, Catalina A.
Poore, Alistair G. B.
Hinojosa, Iván A.
Macaya, Erasmo C.
Pacheco, Aldo S.
Pérez‑Matus, Alejandro
Pino‑Olivares, Óscar
Riquelme‑Pérez, Nicolás
Stotz, Wolfgang B.
Valdivia, Nelson
Villalobos, Vieia
Thiel, Martín
Publisher
Marine BiologyDescription
Metadata
Show full item recordAbstract
Consumer pressure in benthic communities is predicted to be higher at low than at high latitudes, but support for this pattern has been ambiguous, especially for herbivory. To understand large-scale variation in biotic interactions, we quantify
consumption (predation and herbivory) along 2500 km of the Chilean coast (19°S–42°S). We deployed tethering assays at
ten sites with three diferent baits: the crab Petrolisthes laevigatus as living prey for predators, dried squid as dead prey for
predators/scavengers, and the kelp Lessonia spp. for herbivores. Underwater videos were used to characterize the consumer
community and identify those species consuming baits. The species composition of consumers, frequency of occurrence,
and maximum abundance (MaxN) of crustaceans and the blenniid fsh Scartichthys spp. varied across sites. Consumption of
P. laevigatus and kelp did not vary with latitude, while squid baits were consumed more quickly at mid and high latitudes.
This is likely explained by the increased occurrence of predatory crabs, which was positively correlated with consumption
of squidpops after 2 h. Crabs, rather than fsh, were the principal consumers of squid baits (91% of all recorded predation
events) at sites south of 30°S. Fish and crustaceans preyed in similar proportion on P. laevigatus, with most fsh predation
events at northern sites. The absence of any strong latitudinal patterns in consumption rate of tethered prey is likely due to
redundancy among consumers across the latitudinal range, with crustaceans gaining in importance with increasing latitude,
possibly replacing fsh as key predators.