Otolith microchemistry indicates regional phylopatry in the larval phase of an amphidromous fish (Gobiomorphus hubbsi)

ABSTRACT

Knowledge of stock structure is key for the effective management of any fish species. Amphidromous fish, which live and spawn in freshwater but spend a pelagic larval period at sea, have typically been assumed to disperse widely during their larval phase, resulting in populations being sourced from a single unstructured larval pool. We used otolith microchemical analysis to examine the stock structure of bluegill bully (Gobiomorphus hubbsi), a declining amphidromous eleotrid endemic to New Zealand, along the west coast of South Island, New Zealand. Some drainages – even those in close proximity (c. 20 km) – were readily distinguishable based on otolith trace element concentrations, while little structure was evident between other geographically disparate locations. These results indicate that, at least in some cases, locally retained larvae, rather than a single unstructured larval pool, dominates recruitment. Management of bluegill bully and other amphidromous species must therefore consider the possibility of regionally distinct populations.

KEYWORDS:

• Amphidromy
• dispersal
• LA-ICP-MS
• stock structure
• bluegill bully
• diadromy

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Matt G. Jarvis http://orcid.org/0000-0001-8276-1097

Additional information

Funding

The research was funded by the New Zealand Department of Conservation (DOC) and the Department of Zoology, University of Otago. Manna Warburton was financially supported by a doctoral scholarship from the University of Otago. All sampling was conducted with the approval of the University of Otago Animal Ethics Committee and the Department of Conservation.