WEATHERING THE STORM: THE IMPLICATIONS OF WAVE EXPOSURE ON THE DISTRIBUTION, PHENOTYPE AND GROWTH OF A TEMPERATE REEF FISH

• Main Author: Focht, Rebeca C.
• Other Authors: Shima, Jeffrey
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Victoria University of Wellington 2018
• Subjects: Wave exposure; Fish phenotype; Wellington south coast; New Zealand; Southern Ocean
• Online Access: http://researcharchive.vuw.ac.nz/handle/10063/7886

Disturbance is a fundamental process that affects the structure and dynamics of populations. Wave action is an important agent of disturbance in coastal marine systems, and the frequency and severity of wave-associated disturbances is forecasted to increase with climate change. Understanding the effects of waves on coastal marine ecosystems, and the ability of organisms to adapt to wave action, is of growing importance. This is particularly true for intertidal/shallow subtidal species that are subjected to varying, sometimes intense, wave action. Most studies to-date have focused on species with limited mobility (e.g., algae and invertebrates), and have used estimates of wave dynamics that are not always relevant to the spatial scales of these organisms and their home ranges. My thesis focuses on the common triplefin, Forsterygion lapillum, an abundant benthic marine fish inhabiting shallow subtidal and intertidal rocky reefs throughout New Zealand. I develop and implement a protocol to characterise wave climates on an ecologically relevant scale. I evaluate the effects of waves on abundance, phenotype, performance, and behaviour of a reef fish. In Chapter 2, I develop and implement a protocol to characterise wave climate at an appropriate scale. The Wellington south coast is exposed to storm waves that develop in the Southern Ocean and propagate up the east coast of New Zealand. I deployed low-cost HOBO acceleration loggers at two depths within each of six locations along the Wellington south coast to record a time series of wave action at twelve sites. Data from my loggers showed substantial spatial and temporal variation in water acceleration due to interactions between waves and local topography. I used a clustering analysis to characterise my 12 sites as either ‘exposed’ or ‘sheltered’. Assignments to these exposure categories did not match with a priori predictions of exposure, suggesting that wave forces experienced by organisms in the shallow subtidal environment may be difficult to assess from ...