Reproductive trade-offs in a temperate reef fish under high pCO₂ levels

Area of Science:

• Marine Biology
• Climate Change Research
• Ecology

Background:

• Fishes face unprecedented anthropogenic stressors like ocean acidification.
• Energetically demanding processes such as reproduction may be compromised under stress.
• This can lead to reduced offspring fitness and impact population dynamics.

Purpose of the Study:

• To investigate the effects of elevated pCO2 on the reproductive performance of the two-spotted goby (Gobiusculus flavescens).
• To assess potential trade-offs between reproductive output and offspring quality under simulated ocean acidification.

Main Methods:

• Breeding pairs of two-spotted gobies were exposed to control (~600 μatm) and high pCO2 (~2300 μatm) conditions for 4 months.
• Reproductive output (clutches, eggs per clutch) was quantified.
• Offspring size and biomarkers for oxidative stress and energy metabolism were measured.

Main Results:

• Elevated pCO2 significantly increased reproductive activity, with 50% more clutches and 44% more eggs per clutch.
• Larvae from high pCO2 conditions hatched significantly smaller, indicating a trade-off between offspring number and size.
• Evidence suggests altered energy allocation strategies in females under high pCO2.

Conclusions:

• Simulated ocean acidification can stimulate reproductive output in some fish species.
• This increased output comes at the cost of reduced offspring size, potentially affecting individual fitness and population replenishment.
• Findings highlight complex responses to climate change stressors in marine fish.