Southern calamari (Sepioteuthis australis) is an ecologically and economically important species in Tasmania, supporting valuable commercial and recreational fisheries. Recent declines in abundance, spatial variation in stock status, and evidence of shifts in spawning timing have highlighted the need for improved monitoring of spawning activity and reproductive output. Given its short lifespan of approximately 12 months, recruitment success is largely dependent on spawning output and environmental conditions from the preceding year, making the protection of spawning aggregations a key component of sustainable fishery management.
Southern calamari deposit eggs in discrete egg mops, which are primarily attached beneath the leafy canopy of the seagrass Amphibolis antarctica in sheltered inshore habitats. Understanding the spatial and temporal distribution of egg mops is therefore critical for identifying periods of peak spawning activity and informing the timing of spawning closures. However, long-term monitoring programs require methods that are not only reliable but also cost-effective and scalable.
This study evaluates and compares two approaches for estimating egg mop density and spawning activity: traditional SCUBA diver and towed-video surveys. Monthly surveys are being conducted throughout the spawning season across three important spawning and fishing regions around Tasmania, allowing direct comparison of each methods ability to detect spatial and temporal variation in egg mop abundance. The primary aim is to determine whether towed-video surveys can provide a practical and cost-effective alternative to diver-based monitoring while maintaining sufficient accuracy and precision to inform management decisions.
In addition to comparing survey performance, egg mop density data will be integrated with biological and environmental information to investigate the drivers of spawning dynamics and improve understanding of spawning phenology. Results from this work will contribute to the development of efficient monitoring programs and support adaptive management strategies, including spatial and temporal protection of critical spawning habitats for southern calamari in Tasmania.