Dan Hewitt
PhD Student

Dan Hewitt

Centre for Marine Science & Innovation | Evolution & Ecology Research Centre
UNSW Biological, Earth & Environmental Sciences

I am a PhD candidate in the Fisheries and Marine Environmental Research (FAMER) Laboratory. I am broadly interested interested in biological oceanography, recruitment processes, fisheries dynamics and animal movement across marine and estuarine systems.

Project: Spawning, dispersal and fishery dynamics of Giant Mud Crab (Scylla serrata) in south-east Australia

Supervised by: Prof. Iain M. Suthers (UNSW), Dr. Matt D. Taylor (NSW DPI)

Project Description: Giant Mud Crabs (Scylla serrata) are an iconic, high value fisheries species, but catches can be highly variable. Water temperature and estuarine flow (which affects salinity) are known to be a driver of variability in crab catches, however, most studies focus on northern-Australia (i.e. QLD and NT) and have not accounted for variation in recruitment. This project seeks to identify the influence of estuarine flow, temperature and oceanography on the spawning and dispersal of Giant Mud Crab in south-east Australia (NSW) at the southern extent of their range. By better resolving mechanistic linkages between environmental variation and biological processes we aim to resolve drivers of variability in harvest rates for the species, which will aid adaptive fisheries management (e.g., quota setting).

Contact Details

Hewitt, D. E., Schilling, H. T., Hanamseth, R., Everett, J. D., Li, J., Roughan, M., Johnson, D. D., Suthers, I. M., Taylor, M. D. (2022) Mesoscale oceanographic features drive divergent patterns in connectivity for co-occurring estuarine portunid crabs. Fisheries Oceanography. https://doi.org/10.1111/fog.12608

Hewitt, D. E., Niella, Y., Johnson, D. D., Suthers, I. M., Taylor, M. D. (2022) Crabs go with the flow: Declining conductivity and cooler temperatures trigger spawning migrations for female Giant Mud Crabs (Scylla serrata) in subtropical estuaries. Estuaries and Coasts. https://doi.org/10.1007/s12237-022-01061-1

Hewitt, D. E., Smith, T. M., Raoult, V., Taylor, M. D., Gaston, T. F. (2020) Stable isotopes reveal the importance of saltmarsh-derived nutrition for two exploited penaeid prawn species in a seagrass dominated system. Estuarine, Coastal and Shelf Science. https://doi.org/10.1016/j.ecss.2020.106622

Hewitt, D. E., Taylor, M. D., Raoult, V., Smith, T. M., Gaston, T. F. (2021) Diet-tissue discrimination and turnover of δ13C and δ15N in muscle tissue of a penaeid prawn. Rapid Communications in Mass Spectrometry. https://doi.org/10.1002/rcm.9167

Schilling, H., Hewitt, D., Malan, N., Taylor, M., Johnson, D. (2022) Cross-jurisdictional larval supply essential for east Australian spanner crabs (Ranina ranina). Marine and Freshwater Research. https://doi.org/10.1071/MF21348

Hanamseth, R., Hewitt, D. E., Johnson, D. D., Taylor M. D. (2022) An automated image analysis system for estimating fecundity in portunid crabs. Fisheries Research. https://doi.org/10.1016/j.fishres.2021.106140