Changes to fish assemblages visiting estuarine wetlands following the closure of commercial fishing in Botany Bay, Australia

Published source details Saintilan N., Mazumder D. & Cranney K. (2008) Changes to fish assemblages visiting estuarine wetlands following the closure of commercial fishing in Botany Bay, Australia. Aquatic Ecosystem Health & Management , 11, 441-449.
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This study is summarised as evidence for the following.

	Action	Category
	Cease or prohibit all commercial fishing Action Link

Cease or prohibit all commercial fishing

A before-and-after, site comparison study in 2001–2005 of a mangrove and saltmarsh estuary in the Tasman Sea, New South Wales, Australia (Saintilan et al. 2008) found that two years following closure to commercial fishing, there was a different fish assemblage and lower abundance of most species compared to before the closure, and a similar change was found at one of two reference sites in adjacent estuaries. The fish assemblage at the estuary closed to commercial fishing differed before and after closure and overall abundances (mangrove and saltmarsh habitats combined) of only two of the 12 main fish species increased, while the rest decreased (data reported as statistical results - see original paper). The fish assemblage at one of two reference sites in similar nearby estuaries also differed following the closure and no change was observed at the other (data reported as statistical results). The authors suggested that the reported decline in abundance may have been due to an increase in predation by larger fish after the closure. Botany Bay was closed to commercial fishing (netting and trapping) in mid-2002. Fish were surveyed at the Towra Point Nature Reserve in Botany Bay and two nearby reference sites (no details of fishing activity were reported), in June-August and December-February immediately prior to (2001–2002) and two years after (2004–2005) the closure. Fish were sampled using 4 m fyke nets set at 50 m intervals: four replicate deployments in saltmarsh habitat and two in mangroves/site before the closure, increased to three deployments in mangroves after.

(Summarised by: Leo Clarke)