Research Project Summaries 2002-2009 - Marine Parks Authority ...

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3. Ecologically sustainable use3.1 Solitary Islands Marine Park3.1.1 Assessment of marine park zoningTwo main monitoring programs have been conducted in Solitary Islands Marine Park toassess management and zones: a reef fish monitoring program and a mudcrabmonitoring program.Reef fish monitoring program: influence of sanctuary zones on selected reef fishabundanceUVC monitoring surveys of sanctuary zones were conducted from 2002 to 2007, andagain in 2009. Various fish species and assemblages were used as indicators. Annualmonitoring surveys (2002–2009) were also conducted using BRUV. The first baselineor benchmark surveys were carried out June to July 2002, immediately before thecurrent zoning plan commenced.Sixteen sites were surveyed annually using UVC methods in about 10 to 14 m waterdepth. Half of the sites were in sanctuary zones. The influence of the size of thesanctuary zone was also examined, with four sites in small sanctuary zonesestablished in 1992 and four in large sanctuary zones established in 2002. The samesites were resurveyed in winter each year. Six 25-m transects were randomly placedand surveyed at each site by the same diver.In addition, BRUV was used to monitor fishes each year, with nine 30-minute baitedvideo drops in four locations (Malcolm et al 2007). Two of the locations were insanctuary zones. The video stations were set at least 200 m apart, about 20 m deep,on similar habitat of rock reef with coral, near the reef-sand interface. Standard pilchardbaits attracted fish to a viewing area being videoed horizontally for 30 minutes. Relativecounts (maximum number of individuals of a species in the field of view at any timeduring the 30 minute set) were used to compare data sets (Cappo et al 2003). Thesurvey included fishes attracted to the bait, fishes passing through, residents in theimmediate vicinity, and fishes attracted to the activity.These data are part of a long-term monitoring program and have not beencomprehensively analysed or reported, although preliminary analyses indicate thelarger sanctuary zones have shown an increase in abundance relative to non sanctuaryzones for most of the monitored taxa. Reef fish require time to respond to changes inmanagement, studies elsewhere indicate more than 15 years are needed (Russ andAlcala 2004; McClanahan and Graham, 2005). Further UVC sampling is proposed for2011 (nine years after the initial surveys).Mudcrab demographics and monitoringTo assess the effectiveness of the zoning plan in estuaries for protecting mudcrabs,zones that were fished, and subsequently became ‘no-take’, were surveyed eachmonth from December 1998 (Wooli) and July 2000 (Sandon and Corindi) until August2003 (Butcher 2004). The sampling program coincided with changes to the SolitaryIslands Marine Park zoning scheme in August 2002, unchanged since 1991. Thisenabled collection of pre- and post-zoning data and the assessment of mudcrabpopulation responses to reopened areas (Wooli and Corindi) or subsequently closed tocrabbing (Sandon) (Butcher et al 2003, Butcher 2004).Mudcrabs are trapped by recreational and commercial fishers; they can be sampledand successfully released unharmed using the same methods. They also have a18 Solitary Island and Jervis Bay Marine Parks Research Projects Summaries 2002–2009
elatively short lifecycle (three to four years), providing a quick response to protection.Methods of tagging were also assessed. Anchor t-tags inserted into the posteriormargin of the crab did not hinder movement or become detached during moulting.These tags were effective for long-term studies on movement patterns, and were usedthroughout the study. Crab behaviour around traps was assessed in special tanksusing video.The sampling program provided evidence that no-take zones were protectingmudcrabs, there were greater numbers of crabs of all sizes. Higher proportions ofmales were captured in the sanctuary zone sites, possibly due to:males being in higher abundance where traps were deployed, andfemales being more dispersed due to downstream travel as part of spawningbehaviour, andvideo analysis revealed that male crabs were initially dominant around baitedtraps and entered first However, all crabs of each gender soon entered, and didnot leave the trap.Sanctuary zone crabs spilt to adjacent fished areas. The extent of spill-over dependedto some degree on flooding, when low salinity pushed crabs downstream and outsideof sanctuary zones. However, between floods, crabs were primarily caught on theborder of sanctuary zones where recreational fishing pressure was the greatest.Abundances of legal-sized crabs declined within two months of opening areas thatwere previously closed to fishing in the Wooli and Corindi estuaries. Reopening of sitesalso distributed fishing away from the sanctuary zone borders, enabling crabs to movefurther into the fished area. Results suggested that closures are an immediate andeffective management tool for the recovery of overfished mudcrab stocks. At theprotected site, crab numbers and average size increased within months of closing, andthere was no change in the number of crabs caught each month in the area whererecreational trapping resumed.Telemetry studies in the Corindi River showed that the average daily distance moved,and the average distance moved from the release point, was greater in deep channelsthan in shallow Zostera-dominated channels. Therefore, there is a greater probability ofspill-over if sanctuary zones are located where deep channels form the border betweenfished and no-take areas. There is also a greater chance that shallow areas couldbecome locally depleted, being slower to recover after exploitation.The longer-term monitoring program continues from the studies that began in 1998(Butcher et al 2003, Butcher 2004) outlined above. A significant component of theearlier study assessed the influence of sanctuary zones implemented in 2002. Themain objectives of the monitoring program are to:monitor and compare mudcrab densities in zones ‘open’ and ‘closed’ tocrabbing, before and after zoning changes in 2002assess the influence of marine park zones by comparing the length, width andgender ratio of mudcrabs within and between different zonesmonitor the density and relative abundance of mudcrab populations in areasopen to fishing in the Solitary Islands Marine Park, as a locally importantfisheries resource.The three largest barrier estuaries have been monitored: the Wooli Wooli River sinceDecember 1998 and the Sandon and Corindi Rivers since 1999–2000. Each estuaryhas been sampled twice per year (April, December) for three nights. Three traps areSolitary Island and Jervis Bay Marine Parks Research Projects Summaries 2002–2009 19
Page 1 and 2: Solitary Islands andJervis Bay Mari
Page 3 and 4: ContentsSummaryiii1. Introduction 1
Page 5 and 6: SummaryBuilding a network of marine
Page 7 and 8: 1. IntroductionA network of marine
Page 9 and 10: 2. Biodiversity and ecological proc
Page 11 and 12: habitats outside the estuaries of t
Page 13 and 14: Reef fish assemblagesReef fish are
Page 15 and 16: To further examine the influence of
Page 17 and 18: Different types of ASUs supported d
Page 19 and 20: noted that colonies of Turbinaria m
Page 21 and 22: Solitary Island and Jervis Bay Mari
Page 23: Figure 3. Study locations of three
Page 27 and 28: competition permit, had to submit d
Page 29 and 30: Sea turtlesSea turtles include vuln
Page 31 and 32: periodicity for acroporid corals. T
Page 33 and 34: 3.2.2 Population biology and assess
Page 35 and 36: Otolith microchemistry analysis of
Page 37 and 38: Assessing potential impacts associa
Page 39 and 40: y the MPA on reefs throughout the m
Page 41 and 42: Since the completion of this monito
Page 43 and 44: 6. Socio-economic influencesUnderst
Page 45 and 46: Figure 5. Hot spot analysis of over
Page 47 and 48: This study found that marine touris
Page 49 and 50: Visitor monitoring survey - NSW MPA
Page 51 and 52: Marine pests - University of Wollon
Page 53 and 54: Brown J (2000) Non-destructive asse
Page 55 and 56: Gladstone W (2007) Requirements for
Page 57 and 58: Lynch TP (2006), Incorporation of r
Page 59 and 60: Otway NM, Burke AL, Morrison NS, Pa
Page 61 and 62: Smart E (2000) An investigation int
Page 63 and 64: Wilkes K (2009) Boulder assemblages

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