Rare soft corals feature in Kimberley photographic field guide

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More than 90 images, giving a glimpse into the rare soft coral gardens of Australia’s remote northwest, have been compiled in a photographic field guide by Dr Monika Bryce of the Western Australian Museum.

Octocoral (non reef-building coral) specimens collected on five expeditions conducted in 2015 and 2016 in and around Camden Sound, Maret Island, Eclipse Islands and Lynher Bank have been identified and the species are characterised in the guide.

The locations for investigation by the Western Australian Marine Science Institution’s Benthic Biodiversity project team were selected with the WA marine park initiatives in mind, in particular Lalang-garram/Camden Sound Marine Park and the North Kimberley Marine Park in the Cape Bougainville-Cape Londonderry region.

The ship based surveys focussed on the deeper areas, from around 12-100m below low tide, where little information is available from previous Kimberley studies. Samples were also taken in nearshore areas at low tide reef walks and sediment grabs.

The guide is designed to walk scientists through the characters they require to identify species of octocorals. It features images of the octocoral species, and the sclerites that form their skeletons which are used to determine species identifications.

 

Chironephthya sp. 2  Chironephthya sp. 2  sclerites (that form their skeletons)

 

“The simplicity of the guide belies the complex taxonomic science that underpins it, and the enormous amount of time it has taken Monika to identify the 92 species presented in it,” Dr Jane Fromont, Head of Department of Aquatic Zoology at the Western Australian Museum said.

Video of sponge gardens at Nick’s Rock.

“There are rich sponge and octocoral gardens in the Kimberley and this guide gives a snapshot of the octocoral biodiversity.

“This is the first identification guide of octocorals of the Kimberley region,” Dr Fromont said. “As a new resource into a virtually unknown fauna it will be incredibly useful to researchers attempting to identify these animals. It also provides general estimates of abundance and rarity, and the habitats where the animals are found, and is therefore important for managers of the region.”

 

 

Ultimately all available data will be drawn together to provide an overview of the large scale trends in habitats along the Kimberley including:

  • A habitat map identifying the major seabed habitat types throughout the Kimberley.
  • A better understanding and appreciation of the importance of marine biodiversity in the Kimberley (including number of species and identification of species new to science and/or new to the region)
  • An improved ability to plan and manage marine protected areas in the Kimberley.

 

“The Kimberley is an increasingly active, multiple-use marine region, with a growing need for accessible environmental and socio-economic information,” WAMSI Benthic Biodiversity Project leader, Dr Andrew Heyward (AIMS) said. “These are voyages of discovery, which is inherently exciting for the scientists. We expect the project will reveal much about life on the seabed in this region and make a useful contribution to planning and management.”

WAMSI’s joint venture partners, the Australian Institute of Marine Science, CSIRO, Curtin University and Tradional Owners also supported the fieldwork and provided laboratory facilities.

The Octocoral Field Guide, Kimberley, Western Australia can be found at:

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

 

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Dredging Science

Report highlights the importance of seagrass in the Kimberley

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Fish and turtles can, at times, consume all of the growth of the seagrasses: that’s among the findings of a three-year study that has combined science and traditional knowledge to investigate the productivity of seagrasses and other marine plants, and how important this is for the animals of the Kimberley region.

Researchers from CSIRO, The University of Western Australia (UWA) and Edith Cowan University teamed  up with the Bardi Jawi Rangers – who look after more than 250 kilometres of coast and the 340,700-hectare Bardi Jawi Indigenous Protected Area.

The Western Australian Marine Science Institution (WAMSI) project team, including UWA’s Professor Gary Kendrick and CSIRO’s Dr Mat Vanderklift, spent three years studying the seagrasses and macroalgae (large seaweed) that grow on the seafloor along the coast and islands around One Arm Point.

Monitoring seagrass growth is very important to assess stress levels and their resilience to change.

The main plants found in the lagoon habitats by the team were the seagrasses Thalassia (also called turtlegrass) and Enhalus, and the large brown algae Sargassum.

These seagrasses are living at extremes in both temperature oxygen levels (high oxygen during the day and low oxygen during the night), and are under threat from climate change.

All of these plants have high growth rates throughout the year, sometimes exceeding a centimetre a day.

However, the research also found that seasonally variable grazing by a range of large vertebrate herbivores, like fish and turtles can consume all of the growth of the seagrasses.

Microscopic algae were very abundant in some places, but not everywhere, and bacteria were particularly abundant in the sediment under mangroves and seagrasses.

The team discovered that herbivores were abundant and ate a lot of the seagrass.

One of the main herbivores was the rabbitfish (Siganus lineatus) which is also a highly sought after food source for the Bardi Jawi people. Green turtles were also abundant, moving at high tide onto the seagrass beds.

Collaborations with the Bardi Jawi Rangers, who are custodians of the Indigenous Protected Area, added enormous value to the research. The exchange of knowledge with the rangers during the project recognised the importance of seagrass to rabbitfish. Therefore, the research concludes, marine park plans should consider these as Key Performance Indicators.

Bardi Jawi ranger Dwayne George and researcher Monique Grol measuring seagrass growth (Monique Grol)

“Particular care should be taken to ensure that the habitats that contain these plants are not degraded, and are monitored in a way that will ensure that any change — even small — is detected,” Professor Kendrick said.

Some work is still needed to develop methods for monitoring that will work in the Kimberley, and that can be adopted and applied by Indigenous ranger groups for Healthy Country Plan monitoring.

Links:

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program

New genetic stocks of turtles defined in the Kimberley

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New research has uncovered patterns of biological, genetic and developmental change in marine turtles of the Kimberley that could change the way the region is managed.

Marine turtles in the Kimberley nest throughout the year, with flatback turtles stocks separating into distinct summer or winter nesters; generally separated by the Dampier Peninsula.

During breeding season, female turtles emerge from the water and crawl up the beach to dig a nest for a clutch of eggs. Flatback turtles will lay about 50 eggs per nest, while green turtles will lay around 100 eggs per nest. Typically, each female lays between three to five clutches of eggs a season before making the journey to a foraging ground to replenish energy until the next migration 2-4 years later.

Overlap of summer and winter tracks occurs between Lacepede Islands and Dampier Peninsula (WAMSI)

Distribution and Abundance by Parks and Wildlife (Marine Science and GIS Units), and Pendoley Environmental researchers

Aerial counts of turtle tracks along island and mainland beaches found the winter track counts highest at Cape Domett, South Maret, Parry Island and Vulcan Island. The summer track counts were highest at the Lacapedes Islands, Eighty Mile Beach, Maret, Cassini and Oliver Islands.

Ground view of turtle tracks at Cape Domett. Photos (Parks and Wildlife)

Genetic Analysis by Griffith University and CSIRO researchers

Previous genetic studies recognised four major flatback population stocks in Australia. However, the early results from the Western Australian Marine Science Institution’s (WAMSI) Kimberley Marine Research Program discovered five genetic breeding stocks in Western Australia alone.

The previously recognised stocks included the Pilbara and Cape Domett stocks. Three newly recognised stocks are provisionally referred to as the Eighty Mile Beach, Ecobeach, and Maret Island stocks.

The green turtles of the Lacepedes were also a different genetic stock than previously recognized.  The research team of Nyul Nyul rangers and CSIRO are taking a skin biopsy from a day-time nester. (Parks and Wildlife)

According to project leader Dr Scott Whiting from the Department of Parks and Wildlife, the new WAMSI data is also updating the thinking about the green turtle populations.

“Of particular interest was the relationship between turtles from the coastal Kimberley (Lacepede Islands) and Northwest Cape,” Dr Whiting said. “An earlier analysis, based on limited genetic sampling, indicated that these distant regions (>1000km apart) should be considered a single stock. In a new analysis with more data, green turtles nesting at the southwestern extremity of their Australian range (Barrow Island & Northwest Cape) were significantly genetically distinct from those at the Lacepede Islands and so could be considered distinct stocks.”

Effects of Temperature by The University of Western Australia researchers

Another aim of the WAMSI turtle project is to understand the effects of a changing climate on turtle populations. Climate change has the potential to significantly alter the balance of populations as incubation temperature determines the sex of the incubating turtle embryos.

To investigate this question the researchers incubated summer and winter flatback and summer green turtle eggs to record the temperatures that produced mixed sexes, and the temperature producing an equal number of sexes. Predictions based on global climate models were used to adjust temperatures to allow for future projections.

Traditional Knowledge by the Kimberley Indigenous Saltwater Science Project and established ranger groups

A fourth component being developed is to incorporate traditional knowledge about turtle populations from 11 Traditional Owner groups on Country to improve outcomes for management activities in the region’s Marine Parks and Indigenous Protected Areas.

Flatback turtle with satellite tag attached in Eighty Mile Beach Marine Park.  Eighty Mile Beach is a newly identified new flatbacks genetics stock determined in the WAMSI study.  Participants included the Nyangumarta, Ngarla, and Karajarri rangers, Marine Park staff, Marine Science program staff and Murdoch faculty and students. (Parks and Wildlife)

Links:

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

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Kimberley Marine Research Program

Study confirms the ‘uniqueness’ of Kimberley reefs

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A new report confirms that reef systems in the Kimberley continue to produce life amid some of the most extreme conditions yet recorded for reefs worldwide, prompting scientists to ask the question: how much more pressure can the Kimberley reefs cope with?

In the report for the Western Australian Marine Science Institution, scientists have documented what life is like on the Kimberley reefs and how that life responds to environmental variability, including extremes in temperature, oxygen and water levels.

The research team, led by Professor Ryan Lowe and PhD student Renee Gruber from The University of Western Australia’s Oceans Institute, found the daily variability in temperature and dissolved oxygen that occurs on the reef platform is driven by semidiurnal tides (high and low tides that differ in height) and solar (daylight) cycles.

“The shape and friction of the platform causes water to ‘pond’ on the reef for up to 10 hours during each ebb tide (twice daily),” Professor Lowe said. “When these extended low tide periods occur near noon, extreme warming happens on the reef, with temperatures rising by 10°C over several hours and reaching up to 38oC.”

Researchers placed a scaffolding platform on the reef flat to hold a weather station and several sensors that monitored environmental conditions on the reef during their experiments. (Ryan Lowe)

“This high light availability also drives high rates of reef primary production (such as seagrass growth), which releases oxygen into the water column and results in extremes in oxygen saturation (~270%),” Ms Gruber said. “When low tide periods occur near midnight, community respiration (the consumption of oxygen as reef organisms create energy) causes oxygen levels to plummet, reaching very low (hypoxic) levels; low oxygen levels can harm or kill organisms in other ecosystems, and are not typically recorded on reefs.”

Despite extremes in temperature, light, and dissolved oxygen during low tide (seen here on Tallon reef), Kimberley reefs are able to support many species of producers including coral, coralline algae, macroalgae, and seagrass. (Ryan Lowe)

“Despite these extremes, the study found that overall rates of primary production of reef communities were not adversely affected,” Ms Gruber said. “This is a clear example of uniqueness of Kimberley  reef communities, which are well-adapted to conditions that would kill ‘typical’ reef producers.”

The report also highlights that productivity varied on a day-to-day basis, due to the timing of noon relative to low tide, a cycle that lasts about 15 days. It suggests that future studies shorter than this time frame may over- or under-estimate ecological processes (such as productivity).

The study also found the overall average rates of productivity were similar to the global mean for tropical reefs, demonstrating that tide-dominated reefs can maintain moderate rates of production despite daily extremes in temperature.

The report concludes that, while the overall rates of productivity in the Kimberley reef system were comparable to other coral reef habitats worldwide, the environmental conditions under which primary producers survive and grow are extreme.

“This has implications for the resilience of these producers in the face of climate change across the Kimberley environment,” Professor Lowe said. “While these organisms appear well adapted to the local environmental conditions of the Kimberley, many are still likely operating at the edge of their capacity, as evidenced by coral bleaching in the inshore Kimberley associated with the El Niño heat wave in 2016.”

Links:

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program

Naturally resilient Kimberley coral reefs vulnerable to climate extremes

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Western Australian scientists say it’s now clear that global ocean warming is catching up with Kimberley coral reefs which, until the  extreme  marine  heatwave  of  2016,  had  been  largely  spared  from  major  bleaching.

A research project for the Western Australian Marine Science Institution’s Kimberley Marine Research Program has found that coral calcification rates have been remarkably stable over the last 100 years with Kimberley corals growing at rates similar to corals from less extreme reef environments.

However, last year’s mass coral bleaching event was the first time that regional-scale bleaching has been documented on inshore Kimberley reefs, leading researchers to confirm that Kimberley corals are vulnerable to marine heatwaves and climate change despite their ability to withstand temperature extremes in the short term.

Most coral reefs in the southern Kimberley had 30-60% bleaching during the first natural bleaching event in summer 2016 but the full extent of coral mortality and recovery is yet to be determined.

Bleached coral communities near Cygnet Bay, Kimberley, in April 2016.
(Morane Le Nohaïc)

According to co-researcher, Dr Verena Schoepf from The University of Western Australia, most  of  the  severely  bleached  corals  observed  in  April  near  Cygnet  Bay  in  the  Kimberley  have  now  died,  with  the Australian Institute for Marine Science reporting similar findings from Scott Reef.

“Kimberley corals have a remarkable ability to thrive under extreme conditions that many other corals would not survive,” Dr Schoepf said. “However, it is important to understand that even these naturally stress-tolerant corals are still threatened by the increasing frequency of extreme marine heatwaves events associated with climate change.”

Bleached and dead staghorn coral exposed at low tide near Cygnet Bay, Kimberley, in April 2016. (Chris Cornwall)

The researchers found that although Kimberley corals are not immune to bleaching, extreme daily temperature swings enhance the heat stress resistance of intertidal corals. They also found that intertidal corals recovered much better from the natural bleaching event in 2016 than subtidal corals.

“We are now working to understand the physiological and genetic mechanisms underlying the exceptional heat tolerance of Kimberley corals in a collaboration with Curtin and Stanford Universities,” Dr Schoepf said.

Results of the final WAMSI report Resilience of Kimberley coral reefs to climate and environmental extremes: past, present and future are due to be published by the end of the year.

Dr Schoepf will be presenting the latest results at a Lunch and Learn information session at the Department of Parks and Wildlife, Kensington, Western Australia on 27 July, 2017.

The latest project update can be found at www.wamsi.org.au/calcification

Dr Verena Schoepf investigating intertidal coral communities near Cygnet Bay, Kimberley.
(Claire Ross)

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

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Kimberley Marine Research Program

Climate swings enhance marine heatwave risks off the Kimberley coast

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Scientists have confirmed that under global warming, stronger swings of climate variability, on top of the warming trend, will enhance the likelihood of marine heatwave risks off the Kimberley coast.

The findings, published in Scientific Reports, are part of a Western Australian Marine Science Institution Kimberley Marine Research Program investigation into how sensitive the coastal marine waters off the Kimberley are to variability and changes in ocean temperature, sea level, and shelf circulations.

Lead researcher, CSIRO’s Dr Ming Feng, along with a team of scientists and students, looked at historical data and numerical modelling and found that over the past six decades, ocean temperatures off the Kimberley coast have been rising at a moderate rate of about 0.05 to 0.1°C per decade, lower in comparison to waters off the southwest coast of Australia.

“The ocean temperatures on the continental shelf off the Kimberley coast are predominantly influenced by the air-sea exchanges, instead of coastal currents,” Dr Feng said.

“Unlike ocean temperatures off the west coast, sea surface temperatures at Scott Reef  and off the Kimberley coast are warmer during El Niño events, not La Niña events, despite coastal sea levels tending to be higher during La Niña,” Dr Feng explained. “We believe this is due to weaker Australian monsoons and reduced air-sea heat losses to the atmosphere, as well as reduced cloud coverage which enhances solar radiation.”

Sea surface temperature anomaly composites in austral summer during (left panel) El Niño and (right panel) La Niña events.

A large number of the world’s coral reefs were recently influenced by one of the most severe El Niño events on record that lasted from early-2014 to mid-2016. Dubbed the Godzilla-El Niño, it caused severe coral bleaching worldwide, including in regions previously considered resilient to these effects, such as the tropical reefs in the southeast Indian Ocean.

Over the past 30 years, satellite observations have also revealed that the Kimberley coast appears to experience more frequent extreme hot temperatures during summer.

It is believed that ocean temperatures and marine species off the Kimberley coast are highly sensitive to future climate change. There is, however, a lack of knowledge on interannual and longer term variability in the region.

“Poor historical data coverage, rough topography and strong tidal currents have prevented us from gaining a better understanding of the thermodynamics in the region,” Dr Feng said.

“We believe that tidal mixing is likely to play a key role in regional heat balance and biochemical processes. Surface salinity and ocean stratification off the Kimberley coast are also strongly influenced by climate variability.

“In response to increasing greenhouse gases, extreme El Niño and La Niña events are projected to increase,” Dr Feng said. “Our work shows that under the influence of different flavours of El Niño–Southern Oscillation (ENSO), and modified by Indian Ocean and decadal climate modes (like IOD, MJO, IPO) and local air-sea interactions, the coral bleaching potentials vary across the southeast Indian Ocean, and may occur more frequently in a warming world.”

Dr Feng will be presenting the latest results at a Lunch and Learn information session at the Department of Parks and Wildlife, Kensington, Western Australia on 17 August, 2017. The presentation will be made available online at  www.wamsi.org.au/climate-change.

Results of the final WAMSI report Knowledge Integration and Predicting Biophysical Response to Climate Change are due to be published later this year.

Links:

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program

Indigenous partners in the Kimberley – a new guide for researchers

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Advice from two dozen researchers with on-ground Kimberley experience has been integrated with input from around one hundred saltwater Traditional Owners and Indigenous Rangers to develop a protocol for researchers to engage and partner with Traditional Owners on Country.

The new draft research process is being developed within the WAMSI Kimberley Indigenous Saltwater Science project (KISSP).

Gina Lincoln from Mosaic Environmental Consultancy, recently gave an overview of the main process product being developed – ‘Collaborative Science on Kimberley Saltwater Country – A Guide for Researchers’, to a diverse group of managers, scientists and consultants at the Indian Ocean Marine Research Centre in Perth.

Mrs Lincoln explained that the guide is being created to address shortfalls in the existing process and to provide some consistency to researchers embarking on Kimberley coastal and marine research projects.

“The draft Guide walks land and sea researchers through the process of undertaking research projects on country with Indigenous Kimberley saltwater people,” Mrs Lincoln said. “It explains the requirements of identifying the appropriate native title holders, engaging Traditional Owners and planning respectful research around natural & cultural resource management. The Guide is also a database of information, helping researchers learn about the people and Country and resources that may be available to support them as they plan for remote research.”

 

Proposed Kimberley Collaborative Research Cycle 17.02

 

The KISSP group described feedback from attendees at the presentation as positive, with useful insights being collected from a range of stakeholders.

“It was a clear and helpful presentation – and I like the draft document a lot, because of the combination of well-structured common sense for working with Aboriginal land managers and practical information about specific organisations,” one reviewer said.

The process presented within the Guide is open for review by science stakeholders until May 9th. The final draft will be considered for endorsement by the Indigenous governance body in each of the seven participating Kimberley saltwater communities over the following few months.

The guide for researchers is one of several KISSP products in development that will be made available to the science community before the end of the year.

 

Links:

Click here to download a pdf of the presentation slides.

WAMSI KMRP Kimberley Saltwater project page: www.wamsi.org.au/indigenous-knowledge

 

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program

Modelling a picture of the future Kimberley marine environment

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Scientists are working on the final stage of developing models that could estimate the likely effect of changes in population, tourism and climate in the Kimberley to better predict what the future may look like.

By the end of the Western Australian Marine Science Institution’s Kimberley Marine Research Program (KMRP), a staggering 25 research projects will have generated new information about the bio-physical, ecological and social processes affecting the Kimberley marine environment and the main causes of change.

Condensing all this information into a unified picture to better understand the complex interactions to guide conservation decisions is an international team of researchers from CSIRO and ALCES (based in Canada).

Led by CSIRO’s Dr Fabio Boschetti, the team has been building a modelling tool which uses the best available information on the likely future of the region.

 

Simplified, spatially explicit, conceptual model of the working of the Kimberley system, including land, coastal and marine processes

“In general, model predictions are more reliable than the ones we (experts included) may produce without models,” Dr Boschetti said. “Of course, models will not accurately predict what will happen to the system. Rather, they are designed to say something physically and ecologically meaningful about what may happen to the system, should it undergo specific pressures.”

“They are tools which allow us to integrate the available knowledge, include the state-of-the-art understanding of social, economic and ecological processes and account for uncertainty and missing information. We can use them to explore what may happen to the Kimberley region to the year 2050 depending on how the Kimberley system works, what events may occur, and what we do and how we react to these events. Hypothetical or conditional questions, like “if this event occurs, then what may the future look like?’ can be asked. This forces us to focus on the events and conditions which may affect it,” Dr Boschetti said.

Modelling approach based on asking what may happen to the Kimberley region if specific events (scenarios) occur and specific initiatives (management strategies) are adopted

The two computer models are being used in this project to integrate existing knowledge about the Kimberley system to provide an estimation of the likely impacts of different stressors on the land (ALCES) and marine (Ecopath with Ecosim – EwE) environments.

The EwE model is being used to characterise the impact of fishing, tourism, other human uses and climate change on the Kimberley marine ecosystem as well as how different management options, such as controls on fishing effort and spatial closures, can affect the overall impact.

Based on available information on likely future land use in the Kimberley (e.g. mining, energy, aquaculture, crops, livestock, settlements, tourism, transportation) ALCES can simulate how land based processes affect the marine environment via sediment and pollution flows, infrastructure and localised human pressure.

“We do not know precisely how the Kimberley system works, but we have a few working hypothesis that represent a snapshot of how we believe the system is and works now,” Dr Boschetti explained.

“A future is an estimation of what the system may look like several years down the track, according to the model,” Dr Boschetti said. “It is the answer to the question ‘If a specific scenario occurs and we implement a specific management strategy and the system works according to our current knowledge, then how will the system likely respond?”

Determining future outcomes is the final stage of the project to be delivered by October 2017.

More information can be found on the WAMSI KMRP Modelling Project Page: www.wamsi.org.au/modelling-future-kimberley-region

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program

Northwest Australia reveals its unique marine ecosystem

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While unusually warm sea temperatures in the Kimberley region threaten to cause further coral bleaching between April and May, researchers have joined with the Bardi-Jawi Land and Sea Rangers to provide the first detailed look into the process of fish and coral replenishment and the importance of marine plants in the ecosystem.

By the end of the Western Australian Marine Science Institution’s Kimberley Marine Research Program (KMRP) project a team of researchers from five separate institutions will have answered some important questions about this unique environment such as: When do young corals and fish move from the open ocean back into shallow coastal waters? Where do they go? Are there important “nursery” habitats or areas that need protection? Who is responsible for eating the majority of plant material? How much do they eat?

Scientists from the Australian Institute of Marine Science (AIMS), CSIRO, Department of Parks and Wildlife WA (Parks and Wildlife), The University of Western Australia (UWA), Department of Fisheries (DoF) and Western Australian Museum (WA Museum) are working in partnership with the Bardi Jawi Land and Sea Rangers, Traditional Owners (TO’s) and the Kimberley Marine Research Station to provide the first quantitative estimates of coral and fish recruitment and herbivory in the Cygnet Bay / Sunday Island group of the southern Kimberley region.

Study area (Kimberley region)

The core goal of the project is not only to provide primary information on these processes but a blueprint on the appropriate techniques needed to continue to learn what is ‘normal’ in this environment.

“This is one of the first studies in which recruitment has been measured during each month of the year, rather than focusing on one or two months following predicted periods of coral spawning,” AIMS Coral Researcher Dr James Gilmour said. “We have therefore captured periods of spawning outside of those predicted, and also the recruitment of ‘brooded’ larvae – those produced following the fertilisation and development of larvae within the coral’s polyp.

“Initial results indicate that patterns of reproduction at the inshore Kimberley reefs are similar to those offshore, but with more recruitment occurring in some winter and summer months. This is a likely consequence of spawning by some corals, such as the massive Porites bommies, outside of the mass-spawning period in autumn, and also indicates that brooding corals that release larvae throughout much of the year are a significant component of the Kimberley reefs.

“The effect of the mass-bleaching was obvious, dramatically reducing rates of coral recruitment below those expected. These data also provide a useful baseline with which to assess the recovery of coral recruitment in coming years,” Dr Gilmour said.

 

Isopora (left) and Porites (right) coral recruits on terracotta settlement plates. (AIMS)

 

Project leader Dr Martial Depczynski (AIMS) looked at fish recuitment and found generally, recruitment was stronger during the wet season, consistent with other Western Australian ecosystems.

“Although this seasonal pattern was consistent among habitats, each habitat consisted of a unique assemblage of fishes which also varied widely in abundance,” Dr Depczynski said.

“Mangroves uniquely provided a nursery habitat for some very important species such as the snappers Mangrove jack (Lutjanus argentimaculatus – Maarrarn) and Moses perch (Lutjanus russellii).

“Similarly for seagrasses, the Golden-lined rabbitfish (Siganus lineatus – Barrbal) that provide an important source of food were found almost exclusively in seagrass habitats,” Dr Depczynski said.

The research team recorded rates of grazing on seagrass that were higher in the southern Kimberley than anywhere else in the world.

“Average consumption of the seagrass Thalassia hemprichii, otherwise known as turtlegrass, actually outstripped growth in some areas, demonstrating how important seagrass is as a food source,” CSIRO’s Dr Mat Vanderklift said.

 

Grazed turtle grass (Thalassia hemprichii). Turtle grass is a fast grower but in some places grazing by herbivores exceeded estimates of production. (Mat Vanderklift, CSIRO)

 

“What we’ve been able to confirm so far is that differences in species groups vary greatly between habitats meaning that all habitat types in at least the southern Kimberley are equally important,” Dr Depczynski said.

“Also, fish diversity overall was surprisingly low and well below expectations considering its closer proximity to the equator and global centre of fish diversity prompting further questions about the influence of the Kimberley’s unique characteristics and how they affect recruitment processes,” Dr Depczynski said.

The final report is due to be completed mid-2017.

More information can be found on the WAMSI KMRP Key Ecological Processes project Page:  www.wamsi.org.au/key-ecological-processes

 

Graphical representation summarizing findings from juvenile fish stereo RUV surveys during the wet (top panel) and dry (bottom panel) seasons across five habitat types (mangrove, seagrass, algae, coral and inter-tidal pools; separated by dashed lines). Habitats portrayed from left to right follow a typical Kimberley habitat profile from inter-tidal mangroves to adjacent seagrass meadows and algal fields to elevated rocky inter-tidal pools and submerged coral reefs. Colour shades in the background of each habitat represent groupings based on observed statistical differences in fish assemblages among habitats (brown-mangroves, green-seagrass, and pink- algae, coral and inter-tidal pools). Each fish diagram represents a different juvenile species; key to right shows scientific and Bardi Jawi names. Only the ten most abundant and highly influential species distinguishing between fish assemblages are presented. The number of fish in each panel is equivalent to the average number of juvenile fish per RUV replicate (e.g. MaxN = 5 in mangrove habitat during the wet season).

 

Key Ecological Processes project page: www.wamsi.org.au/key-ecological-processes

 

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

Category:

Kimberley Marine Research Program

Scientists learn more about Kimberley dolphin populations

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Australian snubfin dolphins in the Kimberley appear to form at least three genetic populations that require careful management, according to new research.

The snubfin and humpback dolphin are unique to shallow, coastal waters of northern Australia and southern New Guinea. Both species are found off the coast of the Kimberley, though little is known of their numbers, key habitats and movements.

Over the past three years, a Western Australian Marine Science Institution, Kimberley Marine Research Program project has been working to answer some of these questions, by surveying local populations, collecting genetic samples, and developing new tools to help monitor these elusive species.

The research team from Murdoch and Curtin universities found that both snubfin and humpback dolphins occurred at all sites surveyed, although in varying numbers.

 

The team conducted different fieldwork in a number of locations across the Kimberley, and presented data on dolphin relative abundance (R), population genetic structure (G) and/or passive acoustic monitoring (A).

 

Humpback dolphins were observed in similarly low numbers at most sites, while snubfin dolphins appeared to occur in greater numbers at a few discrete locations.

Small local populations of snubfins were apparent at Cone Bay and the Prince Regent River; however, previous research showed the Dampier Peninsula sites of Roebuck and Cygnet Bay to support greater numbers, highlighting these sites as key habitats for snubfin dolphins.

Genetic analyses, led by Murdoch University’s Dr. Alex Brown, showed that not all snubfin dolphins in the Kimberley could be considered the same population.

 

Using the biopsy darting system to collect dolphin genetic samples in Cone Bay, with assistance from Dambimangari Ranger Edmund Jungine. Photo: Alex Brown.

 

Evidence suggests that there is very limited movement of snubfin dolphins between Roebuck Bay and King Sound, and that animals sampled further north and east may represent a third genetic population.

Analyses of humpback dolphin genetic samples revealed a lack of gene flow between animals sampled in the Kimberley and the Pilbara regions.

“It’s important for decision makers to recognise this genetic structure in order to minimise any threats to small, isolated, local populations,” Dr. Brown said. “For both species, more genetic samples are required in the north/east of the Kimberley to better understand the connectivity of local populations.”

“However, monitoring these species can be tricky, particularly in areas where they are unfamiliar with and shy of boats,” Dr Brown said.

Several scientists in the dolphin project team have been working on this problem by exploring the use of passive acoustic monitoring to detect and monitor dolphin presence and use of particular areas.

 

Acoustic data loggers, developed by Curtin University, were deployed for up to three weeks at Cygnet and Roebuck Bay, recording dolphin vocalisations and allowing the Curtin researchers to characterise the natural soundscape of the two areas. Photo: Alex Brown.

 

This new technology was able to pick up the whistles and clicks that dolphins make as they travel, forage and socialise, and the research team uncovered several new whistle types to add the species’ repertoire. However, more work is required before the two species can be efficiently distinguished and the number of animals present can be identified.

 

An audiogram of echolocation clicks, pulsed ‘buzz’ sounds, and tonal whistles
recorded in the presence of snubfin dolphins.

 

A key part of this research was collaborating with local stakeholders. The research team collected data alongside Yawuru, Bardi-Jawi, Dambimangari and Balanggarra Traditional Owners, as well as regional Parks and Wildlife staff, generating valuable training opportunities.

 

Murdoch University researchers work alongside Balanggarra Rangers Wesley Alberts and Wayne Moore to collect individual identification photos of humpback dolphins in the Cambridge Gulf. Photo: Alex Brown.

 

The data collected, along with the improved local collaboration, will help with future research and monitoring in the region.

The full research findings presentation is available on the WAMSI dolphin project webpage.    

 

The $30 million Kimberley Marine Research Program is funded through major investment supported by $12 million from the Western Australian government’s Kimberley Science and Conservation Strategy co-invested by the WAMSI partners and supported by the Traditional Owners of the Kimberley.

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Kimberley Marine Research Program