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Modeling Population Dynamics for Sustainable Harvest of Orange Clownfish, Emma Schlatter [et al.]

Modeling Population Dynamics for Sustainable Harvest of Orange Clownfish, Emma Schlatter [et al.]

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Monitoring fisheries in the Phoenix Island

Protective Area by satellite

Johnny Aase



∗ 1,2



1

2



Institute for Marine and Antarctic Studies (IMAS) – Private bag 129 Hobart TAS 7001, Australia

Norwegian Defence Cyber Academy (NDCA) – PO Box 800 Postmottak 2617 Lillehammer, Norway



The purpose of this presentation and paper is to demonstrate how satellite-based Automatic

Identification System (AIS) can monitor the activities of fishery vessels and reefers in Kiribati’s

Phoenix Island Protective Area (PIPA).

AIS is a system designed to improve safety at sea. All vessels over 300 tons and all passenger

ships irrespective of size shall carry a transponder that sends static and dynamic information

about the vessel to other ships and land stations. Examples of static information are the ships

name, IMO- and MMSI-numbers, while the dynamic information is e.g. course, speed over

ground and position. This information can be received by satellites in low Earth orbit. Norway

has currently two such sensors in polar orbit and one on the International Space Station. The

first, AISSat-1, was launched in July 2010. Data are recorded globally and downloaded every 100

minutes, and are immediately available for Norwegian authorities. More satellites are scheduled

for launch in 2017 and 2018.

In my presentation I will show statistics about fishery vessels in the PIPA, and show how

specific vessels can be tracked in the high seas or remote waters in almost real time.

One obvious weakness with AIS is that the transponder can be turned off or be set to transmit

false information. One way to circumvent this problem is by using images from optical or radar

satellites. I will show how such data, which are available on the internet for free, can be used

to verify AIS transmissions.







Speaker



155



Performance of the Great Barrier Reef

Marine Park since the 2004 re-zoning

Mike Emslie

1



∗ 1



Australian Institute of Marine Science (AIMS Townsville) – Australian Institute of Marine Science

PMB 3, Townsville MC Townsville 4810, Queensland, Australia, Australia



Networks of no-take marine reserves (NTMRs) are widely advocated for preserving exploited

fish stocks and for conserving biodiversity. We used underwater visual survey data of coral reef

fish and benthic communities to quantify the short- to medium-term (5 to 30 years) ecological

effects of the establishment of NTMRs within the Great Barrier Reef Marine Park (GBRMP).

The density, mean length and biomass of principal fishery species, coral trout (Plectropomus

spp.), were consistently greater in NTMRs than on fished reefs over both the short- and mediumterm. However, there were no clear or consistent differences in the structure of fish or benthic

assemblages, non-target fish abundance, fish species richness or coral cover between NTMR

and fished reefs. There was no indication that the displacement and concentration of fishing

effort had reduced populations of coral trout on fished reefs. A severe tropical cyclone impacted

many survey reefs during the study, causing similar declines in coral cover and fish density

on both NTMR and fished reefs. However, coral trout biomass declined only on fished reefs

following the cyclone. The GBRMP is performing as expected for the protection of fished

stocks and biodiversity in a developed country where fishing is not excessive and targets a

narrow range of species. Although NTMRs cannot directly protect coral reefs from regionalscale acute disturbance, impacted NTMR reefs supported higher biomass of key fishery-targeted

species, following a strong tropical cyclone and should provide valuable sources of larvae that

will enhance population recovery and long-term persistence.







Speaker



156



Regional Differences in Fishing Pressure

and Habitat Quality Alter the Organic

Matter Supporting Fish in a Temperate

Rocky Reef Community

Jacquetta Udy



∗† 1



, Stephen Wing



1



1



University of Otago (UO) – Department of Marine Science University of Otago 310 Castle Street

Dunedin 9016 New Zealand Department of Marine Science University of Otago 310 Castle Street

Dunedin 9016 New Zealand Department of Marine Science University of Otago 310 Castle Street

Dunedin 9016 New Zealand Department of Marine Science University of Otago 310 Castle St Dunedin

9016, New Zealand



Temperate reef fish community composition is affected by the presence of macroalgae as it

provides a complex habitat. However, there is limited evidence for the trophic importance of

macroalgae to temperate reef fish, and very little information on how human disturbances alter

the trophic contribution of macroalgae. This study aims to resolve the relative importance of

natural patterns in productivity of habitats versus fishing pressure in determining the primary

organic matter source of the reef fish community. We examined fish community composition between fished and unfished communities in Fiordland and the Marlborough Sounds, New Zealand,

with an orthogonal design covering habitats with varied algal densities. Fiordland has a largely

undeveloped catchment with minimal fishing pressure, where as Marlborough Sounds has been

subjected to land clearing and ongoing fishing pressure. Stable isotope analysis was used to

determine the trophic position of different species and hence elucidate the trophic contribution

of macroalgae to each species. We showed that the primary organic matter source supporting

the fish community did not differ between habitats or fishing pressures within each region, however there was a significant difference between regions. In Fiordland the community was mainly

supported by macroalgae, with the exploited species using a significantly higher proportion of

macroalgae than the non-exploited species. However in Marlborough, were there has been significant declines in macroalgae abundance attributable to trophic cascades and sedimentation,

the community was predominantly supported by pelagic production. These results demonstrate

that land based run off and fishing pressure both alter the energetics of fish communities and

can adversely impact on productivity of fisheries resources.









Speaker

Corresponding author: udyja649@student.otago.ac.nz



157



Subsistence harvesting by a small

community does not substantially

compromise coral reef fish assemblages

Tyson Martin ∗ 1 , Rod Connolly 1 , Andrew Olds 2 , Daniela Ceccarelli 3 ,

Douglas Fenner 4 , Thomas Schlacher 2 , Maria Beger 5,6

1



3



4



Australian Rivers Institute – Coast and Estuaries, and School of Environment, Griffith University –

Gold Coast, QLD, 4222, Australia

2

School of Science and Engineering, University of the Sunshine Coast – Maroochydore QLD 4558,

Australia

ARC Centre of Excellence for Coral Reef Studies, James Cook University – Maroochydore QLD 4558,

Australia

Pacific States Marine Fisheries Commission – POB 7390, Pago Pago, AS 96799 USA, American Samoa

5

ARC Centre of Excellence for Environmental Decisions, Centre for Biodiversity and Conservation

Science, The University of Queensland – Brisbane QLD 4072, Australia

6

School of Biology, Faculty of Biological Sciences, University of Leeds – LS2 9JT, United Kingdom



Fisheries usually first remove large predators before switching to smaller species, causing

lasting changes to fish community structure. Reef fish provide essential protein and income

for many people, and the impacts of commercial and high-intensity subsistence fishing on reef

fish are well documented. However, how fish communities respond to low levels of subsistence

fishing using traditional techniques (fishing for food, few fishers) is less well understood. We

use three atolls in the Marshall Islands as a model system to quantify effects of commercial and

subsistence fishing on reef fish communities, compared to a near-pristine baseline. Unexpectedly,

fish biomass was highest on the commercially-fished atoll where the assemblage was dominated

by herbivores (50% higher than other atolls) and contained few top predators (70% lower than

other atolls). By contrast, fish biomass and trophic composition did not differ between pristine

and subsistence-fished atolls– top predators were abundant on both. We show that in some

cases, reefs can support fishing by small communities to provide food but still retain intact fish

assemblages. Low-intensity subsistence fishing may not always harm marine food webs, and we

suggest that its effects depend on the style and intensity of fishing practised and the type of

organisms targeted.







Speaker



158



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