IMPACT OF FLUCTUATING TEMPERATURE AND ELEVATED CO2ON THE GROWTH, SURVIVAL, AND OXYGEN CONSUMPTION OF JUVENILE PINTO ABALONE HALIOTIS KAMTSCHATKANA KAMTSCHATKANA JONAS

Abstract

Pinto abalone populations in the Salish Sea, WA have declined precipitously in the last several decades and have not recovered despite fishery closure in 1994. The Puget Sound Restoration Fund, in collaboration with state and federal agencies, has been outplanting juvenile pinto abalone at sites in the San Juan Archipelago, and some sites are much more successful than others despite similar physical characteristics. The sites, however, likely differ in oceanic parameters, such as temperature, salinity, and pH, which are in turn changing as the climate of the Earth is changing. The purpose of this study was to investigate the effects of temperature fluctuation and pCO2levels on the survival, growth, and oxygen consumption of juvenile pinto abalone. In a fully crossed experiment, juvenile pinto abalone were held at either currently ambient (400 ppm) or elevated (1,200 ppm) pCO2and at constant (10°C) or fluctuating (10 → 14 → 10°C) temperature. Survival was monitored weekly and growth was measured after 4 wk. In a second experiment, abalone were held in the same crossed pCO2and temperature treatments, and oxygen consumption was measured. High pCO2and fluctuating temperature both significantly decreased abalone survival. Abalone growth was not affected by pCO2level (temperature could not be analyzed due to very poor survival in the fluctuating temperature treatments). In addition, there was an interaction between fluctuating temperature and pCO2level on abalone oxygen consumption. Abalone in the constant temperature treatment had higher oxygen consumption when exposed to elevated pCO2; however, this pattern was not observed in the fluctuating temperature treatment. The results of this experiment indicate that outplant sites with minimal temperature fluctuation and lower pCO2levels could lead to improvements in outplanting success of juvenile pinto abalone.