Early post-settlement mortality is one of the main processes determining distribution and abundance patterns of marine benthic invertebrates. Most scallops have an attached phase as spat before they release the byssus and move onto the soft sediments. Thus, spat differ from other stages of life in their use of microhabitat, lack of mobility, and therefore in their vulnerability to mortality processes such as predation. However, the contribution of predation to explain levels of mortality experienced by spat and early juvenile scallops is unknown. Complex habitats such as seagrasses and algae provide a substrate upon which spat can attach and might confer an advantage as a refuge from predation. This study investigates the contribution of early post-settlement predation on abundance of Pecten fumatus and determines the role of the algae Hincksia sordida as a refuge from predation. Data were collected using field observations, a predator exclusion experiment, and tethering techniques. Mortality of up to 85% during the first weeks after settlement appeared to have prevented the establishment of an adult population at our study site. Mats of the macroalgae H. sordida provided a settlement substrate for P. fumatus spat. However, increased algal biomass did not provide greater protection from predation to juvenile scallops than lower algal biomass. Our study suggests that prey survival in submersed vegetation is likely to be dynamic among years, and affected by prey behaviour and density as well as the characteristics of the submerged vegetation.

Item Type:	Refereed Article
Keywords:	bivalves, habitat complexity, predation, macroalgae, submerged vegetation
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Fisheries sciences
Research Field:	Aquaculture and fisheries stock assessment
Objective Division:	Animal Production and Animal Primary Products
Objective Group:	Fisheries - wild caught
Objective Field:	Wild caught edible molluscs
UTAS Author:	Mendo, T (Dr Tania Mendo Aguilar)
UTAS Author:	Lyle, JM (Associate Professor Jeremy Lyle)
UTAS Author:	Semmens, JM (Professor Jayson Semmens)
ID Code:	101197
Year Published:	2015
Web of Science® Times Cited:	2
Deposited By:	IMAS Research and Education Centre
Deposited On:	2015-06-11
Last Modified:	2017-11-04
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