Recruitment of marine organisms around Wellington, New Zealand a model natural system to examine causes and consequences of variability in larval quality in mussels and reef fish

PHILLIPS, N.E.*; SHIMA, J.S.; Victoria University of Wellington; Victoria University of Wellington: Recruitment of marine organisms around Wellington, New Zealand: a model natural system to examine causes and consequences of variability in larval quality in mussels and reef fish

Accumulating evidence from laboratory experiments on a range of marine taxa indicates that variation in larval history can influence probability of recruitment success by impinging on the performance of early juveniles. To date much less has been reported on both the causes and consequences of variable larval quality for recruitment of natural populations of marine organisms. In New Zealand, we are using natural environmental variability between adjacent water masses (Wellington Harbour and Cook Strait) to examine these issues in two related studies. In the first, we monitor natural variability in larval size and lipid content for newly settled mussels, and explore relationships between larval quality, larval quantity, and probable recruitment success. We also use CTD data from moorings in Wellington Harbour to determine potential environmental sources of variability in larval quality. In a second study, we examine recruitment of a common reef fish in this region. Using otolith microchemistry to evaluate larval environmental fingerprints, we identify 3 dispersal syndromes (i.e. fish with similar patterns of trace element concentrations across developing larval otoliths), and explore the proportional contributions of these syndromes to discrete recruitment events. Larval quality (total energetic content) covaries spatio-temporally with dispersal syndromes, and experimental translocations of recently settled fish among sites suggest larval quality and site quality interact to determine differential recruitment success among syndromes, and potentially mediate patterns of demographic connectivity among populations.

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