Houtman Abrolhos Research Articles

New records and distribution extension of Nassarius karinae Usticke, 1971 (Mollusca: Gastropoda: Nassariidae) in the SW Atlantic

We report two new records of Nassarius karinae Usticke, 1971, from Minerva Seamount and Abrolhos Archipelago, off northeastern Brazil. The new records extend the known geographic range of the species ca. 1000 km southward from Pernambuco to Bahia. These are also the first records of the species in Bahia. Additional notes on shell morphology and comparisons with other congeners are provided herein.

Macrophytobenthic flora of the Abrolhos Archipelago and the Sebastião Gomes Reef, Brazil

The Abrolhos Bank, located on the coast of Bahia, Brazil, harbors the largest coral reef system in the South Atlantic. This area has attracted the attention of biologists because of its peculiar mushroom-shaped structures, locally known as “chapeirões”, and endemic species of corals and other organisms. The macrophytobenthos compartment plays an important ecological role in the functioning of the bank, and some reports on the presence of seaweeds and seagrasses have been published; however, the data are fragmentary, and a more detailed survey of the macrophytobenthos compartment is lacking. Here we consolidate the information available and add new data obtained from two expeditions focused on seaweed and seagrass diversity from two sectors of the bank: the islands of the Abrolhos archipelago (AA) and the Sebastião Gomes Reef (SG). These sites were selected for their contrasting characteristics. Specifically, SG (15km off the mouth of the Caravelas River) is subjected to a broader range of anthropogenic impacts and to input of terrigenous sediments, while the AA (54km offshore) is surrounded by calcareous biogenic sediments, has clearer water and is less affected by human activities. Macrophytobenthic species richness on both reference areas is larger than previously thought. Considering previous records, there are 164 species of macrophytes in AA and 111 species in SG, of which 59 and 74 species are first records for each respective location. The higher species richness at the AA may result from a higher habitat complexity and lower turbidity, but a potential negative effect of enhanced human impacts at SG cannot be ruled out. Considering that macroalgae are relevant components of the benthic community, as producers and structurer organisms, the data presented herein provide a reliable baseline for future environmental studies, and thus may contribute to improve management policies within the unique ecosystem of Abrolhos.

Macrofauna associated with the brown algae Dictyota spp. (Phaeophyceae, Dictyotaceae) in the Sebastião Gomes Reef and Abrolhos Archipelago, Bahia, Brazil

The taxonomic richness and distributional patterns of the macrofauna associated with the algae genus Dictyota from the Abrolhos Bank (Eastern Brazilian coast) are analyzed. Macrofauna comprised a total of 9586 specimens; a complete faunal list of the most abundant taxa (Crustacea, Polychaeta and Mollusca, accounting for 95.6%) resulted in 64 families and 120 species. Forty six species are registered for the first time for the Abrolhos Bank, of which 3 are also new for the Brazilian coast. The most abundant families were Ampithoidae amphipods (with Ampithoe ramondi as the main faunal component), Janiridae isopods, Rissoellidae gastropods and Syllidae polychaetes. Comparisons were made between summer and winter periods and among sites from Sebastião Gomes Reef, near the coast, and from Siriba Island, in the Abrolhos Archipelago, away from the mainland. Algae size was lower in the summer, when faunal density was higher, suggesting a possible effect of grazing. Macrofaunal communities were significantly different among sites and periods. Coastal and external communities were markedly different and winter had the greatest effects on the fauna. Environmental conditions related to sediment type and origin and turbidity appear to be a good scenario for our macrofauna distribution results.

Using artificial illumination to survey nocturnal reef fish

Effects of three different light wavelengths (blue, red and white) were assessed on the composition, abundance and behaviour of nocturnal fish at the Houtman Abrolhos Islands, Western Australia. The effects of fishing were also considered by further examining the combined effects of lighting and fishing (open vs. closed areas). Data were collected using baited remote underwater stereo-video systems (stereo-BRUVs), which were equipped with red (620–630nm), white (550–560nm) or blue (450–465nm) lights. The total number of individuals, relative abundance of fish and assemblage composition differed under each lighting condition and fishing status. The greatest number of individuals was observed on samples illuminated by red lights (43% of all individuals surveyed). The species Apogon doederleini, Gymnothorax woodwardi, and Pempheris klunzingeri were each more abundant and spent longer in the field of view of the cameras using red lights. In contrast to white and blue light, the wavelength of red light is thought to be beyond the visual sensitivity of these fish species, and may not have affected their behaviour. The heavily targeted species, Pagrus auratus, were twice as abundant on stereo-BRUVs illuminated by blue lights and white lights than on red lights, but only in areas closed to fishing. This higher abundance on blue and white lights may have been due to the attraction of baitfish to these lights. In addition to the effects of lighting, clear effects of fishing were noted on nocturnal populations of P. auratus. Light wavelength can influence observations and measurements made of a nocturnal fish assemblage, and therefore careful consideration of choice of light wavelength should be made for nocturnal studies using artificial illumination on stereo-BRUVs.

Comment on: Coarse clast ridge sequences as suitable archives for past storm events? Case study on the Houtman Abrolhos, Western Australia

Journal of Quaternary ScienceVolume 28, Issue 2 p. 210-212 Correspondence Comment on: Coarse clast ridge sequences as suitable archives for past storm events? Case study on the Houtman Abrolhos, Western Australia Jonathan Nott, Jonathan Nott School of Earth and Environmental Sciences, James Cook University, Cairns, AustraliaSearch for more papers by this author Jonathan Nott, Jonathan Nott School of Earth and Environmental Sciences, James Cook University, Cairns, AustraliaSearch for more papers by this author First published: 13 February 2013 https://doi.org/10.1002/jqs.2610Citations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume28, Issue225/26 February 2013Pages 210-212 RelatedInformation

Reply to Comment on: Coarse clast ridge sequences as suitable archives for past storm events? Case study on the Houtman Abrolhos, Western Australia

Prehistoric storm records are relatively scarce in most parts of the world. This article presents storm records derived from coral rubble-based geological archives of the Houtman Abrolhos Archipelago located off the west coast of Australia, where the southernmost coral reefs of the Indian Ocean are found. Winter storm swell from the circum-Antarctic ‘Brave Westerlies’, as well as tropical cyclone waves, have left numerous ridge systems on dozens of islands of the archipelago, all composed of coral rubble from adjacent reefs. At three islands, seven ridge systems were dated by three different methods: U-series (68 dates), radiocarbon (64 dates), electron spin resonance (7 dates); 139 radiometric dates span the last 5500 years of the Holocene. In contrast to the geomorphological interpretation, the age sequences show ‘inversions’, hiatuses and different ages for the same ridge, all pointing to complicated ridge formation processes. Time gaps, some exceeding 1000 years, are interpreted as phases of erosion and not as phases without storm activity.

“Changed as to a tiger”: Considering the Wreck of the <em>Batavia</em>

WHEN THE SUN ROSE OVER THE HOUTMAN ABROLHOS archipelago eighty kilometers off the west coast of Australia on Friday, 12 June 1629, it revealed a man clinging to a bowsprit spar of a wrecked ship. Cornelisz had spent two days alone on the Batavia as the waves and the coral joined forces to rip apart the hull. Eight days previously, the Dutch East India Company retourschip had struck the Morning Reef with all her canvas set and, in the words of the Cambridge historian Mike Dash, had impaled herself on the half-hidden reef that had been lying in her path (5). On the day of the wreck, around 280 crew, passengers, and Company employees had been ferried to a small, stark island, which they would name Batavia's Graveyard (now Beacon Island). Forty belligerent men remained on the ship, raiding the grog stores and becoming drunk and disorderly. In a carnivalesque turn, characteristic of sailors' behavior after shipwreck, they donned officers' uniforms taken from the Great Cabin and broke open the chests of Company coin. Only when the ship beneath them began to give way did they finally head for the safety of the islands.Cornelisz alone remained on board. Like most sailors and passengers on seventeenth-century ships, he could not swim. He gazed with horror at the churning blue waters beneath him and at the treacherous reef into which the ship had ploughed a deep, ragged trench. He could not get up the courage to let go. Eventually, the choice was taken from him. The bowsprit broke apart and Cornelisz fell into the shallows amidst swirling driftwood and other debris from the wreck. He arrived on Batavia's Graveyard to the relief of the assembled castaways. Commendeur Francisco Pelsaert and Ariaen Jacobsz, the Batavia's skipper, along with 38 others, had set off for Batavia (Jakarta) in the ship's longboat shortly after the wreck. Their departure had been clandestine for they knew that the desperate survivors, fearing for their future on these stark, weather-beaten islands, might swamp the small vessel. Traitor's Island to the south was named by those who remained to mark this betrayal. As Under-Merchant on the voyage, Cornelisz was the most senior Company representative remaining, and he seemed a godsend.Three and a half months later, Cornelisz was executed, along with several young men he had gathered about him to do his bidding. First his hands were hacked off with a hammer and chisel; then he was hanged from the rudimentary gallows erected on Seal Island at the orders of Pelsaert, who had returned from Batavia in a VOC jacht, the Sardam, to rescue the survivors.Under torture, Cornelisz confessed to ordering his henchmen to murder 96 men and boys in the employ of the Company, 12 women and 7 children. When victims were drowned, their remains were left to drift away with the currents. Those who were strangled, stabbed to death, or hacked with cutlasses or axes were buried in shallow graves. The sentence passed on the self-styled Captain-General of the castaways by the VOC tribunal was the most severe that it could impose. In his summary of Cornelisz's crimes, read out just prior to the hanging, Pelsaert struggled to come to terms with the Under-Merchant's depravity. Jeronimus Cornelisz of Haarlem, aged about 30 years, apothecary, and late under Merchant of the ship Batavia, has misbehaved himself so gruesomely and has gone beyond himself, yea has even been denuded of all humanity and has been changed as to a tiger (qtd. in Drake-Brockman 172). In 2010, I traveled to the Abrolhos archipelago in the obscure hope that the place would guide my reflections on scholars' accounts of Cornelisz's transformation, if such it was. I also found myself enmeshed in more personal reflections on the recalcitrance of the past.Our flight out of Geraldton Airport to the landing strip on East Wallabi is delayed for much of the morning. A series of squalls are sweeping in from the south-west and the pilot is loath to confront the crosswinds. …

Response of diurnal and nocturnal coral reef fish to protection from fishing: an assessment using baited remote underwater video

Diel variation is known to alter the composition and structure of reef fish assemblages. What is unknown is how nocturnal fish assemblages respond to closed fishery area management. Diurnal and nocturnal reef fish assemblages at the Houtman Abrolhos Islands, Western Australia, were studied using baited remote underwater stereo-video systems (stereo-BRUVs). Surveys were conducted during the day and at night (using blue illumination) from three sites inside and three sites outside a closed fishery area (CFA). The relative abundance of 116 fish species from 41 families was recorded. Significant changes were observed in fish assemblage structure from day to night (driven by high dispersion at night) and in areas open versus closed to fishing (driven by increased abundance within the CFA). The effect of protection from fishing was consistent for both diurnal and nocturnal fish assemblages. Closer examination of six targeted fish species showed that their response to diel changes and the absence of fishing pressure varied from species to species. The targeted fishes Pagrus auratus and Glaucosoma hebraicum were sampled during the day and at night with both species responding positively to protection from fishing. Results suggest that the inclusion of diurnal and nocturnal fish assemblage data will provide an improved ability to assess the effectiveness of closed fishery area management.

Coarse clast ridge sequences as suitable archives for past storm events? Case study on the Houtman Abrolhos, Western Australia

AbstractPrehistoric storm records are relatively scarce in most parts of the world. This article presents storm records derived from coral rubble‐based geological archives of the Houtman Abrolhos Archipelago located off the west coast of Australia, where the southernmost coral reefs of the Indian Ocean are found. Winter storm swell from the circum‐Antarctic ‘Brave Westerlies’, as well as tropical cyclone waves, have left numerous ridge systems on dozens of islands of the archipelago, all composed of coral rubble from adjacent reefs. At three islands, seven ridge systems were dated by three different methods: U‐series (68 dates), radiocarbon (64 dates), electron spin resonance (7 dates); 139 radiometric dates span the last 5500 years of the Holocene. In contrast to the geomorphological interpretation, the age sequences show ‘inversions’, hiatuses and different ages for the same ridge, all pointing to complicated ridge formation processes. Time gaps, some exceeding 1000 years, are interpreted as phases of erosion and not as phases without storm activity. Copyright © 2012 John Wiley & Sons, Ltd.

Turning up the Heat: Increasing Temperature and Coral Bleaching at the High Latitude Coral Reefs of the Houtman Abrolhos Islands

BackgroundCoral reefs face increasing pressures particularly when on the edge of their distributions. The Houtman Abrolhos Islands (Abrolhos) are the southernmost coral reef system in the Indian Ocean, and one of the highest latitude reefs in the world. These reefs have a unique mix of tropical and temperate marine fauna and flora and support 184 species of coral, dominated by Acropora species. A significant La Niña event during 2011 produced anomalous conditions of increased temperature along the whole Western Australian coastline, producing the first-recorded widespread bleaching of corals at the Abrolhos.Methodology/ Principal FindingsWe examined long term trends in the marine climate at the Abrolhos using historical sea surface temperature data (HadISST data set) from 1900–2011. In addition in situ water temperature data for the Abrolhos (from data loggers installed in 2008, across four island groups) were used to determine temperature exposure profiles. Coupled with the results of coral cover surveys conducted annually since 2007; we calculated bleaching thresholds for monitoring sites across the four Abrolhos groups.Conclusions/ Significance In situ temperature data revealed maximum daily water temperatures reached 29.54°C in March 2011 which is 4.2°C above mean maximum daily temperatures (2008–2010). The level of bleaching varied across sites with an average of ∼12% of corals bleached. Mortality was high, with a mean ∼50% following the 2011 bleaching event. Prior to 2011, summer temperatures reached a mean (across all monitoring sites) of 25.1°C for 2.5 days. However, in 2011 temperatures reached a mean of 28.1°C for 3.3 days. Longer term trends (1900–2011) showed mean annual sea surface temperatures increase by 0.01°C per annum. Long-term temperature data along with short-term peaks in 2011, outline the potential for corals to be exposed to more frequent bleaching risk with consequences for this high latitude coral reef system at the edge of its distribution.

Bait Effects in Sampling Coral Reef Fish Assemblages with Stereo-BRUVs

Baited underwater video techniques are increasingly being utilised for assessing and monitoring demersal fishes because they are: 1) non extractive, 2) can be used to sample across multiple habitats and depths, 3) are cost effective, 4) sample a broader range of species than many other techniques, 5) and with greater statistical power. However, an examination of the literature demonstrates that a range of different bait types are being used. The use of different types of bait can create an additional source of variability in sampling programs. Coral reef fish assemblages at the Houtman Abrolhos Islands, Western Australia, were sampled using baited remote underwater stereo-video systems. One-hour stereo-video recordings were collected for four different bait treatments (pilchards, cat food, falafel mix and no bait (control)) from sites inside and outside a targeted fishery closure (TFC). In total, 5209 individuals from 132 fish species belonging to 41 families were recorded. There were significant differences in the fish assemblage structure and composition between baited and non-baited treatments (P<0.001), while no difference was observed with species richness. Samples baited with cat food and pilchards contained similar ingredients and were found to record similar components of the fish assemblage. There were no significant differences in the fish assemblages in areas open or closed to fishing, regardless of the bait used. Investigation of five targeted species indicated that the response to different types of bait was species-specific. For example, the relative abundance of Pagrus auratus was found to increase in areas protected from fishing, but only in samples baited with pilchards and cat food. The results indicate that the use of bait in conjunction with stereo-BRUVs is advantageous. On balance, the use of pilchards as a standardised bait for stereo-BRUVs deployments is justified for use along the mid-west coast of Western Australia.

Effects of climate variability on breeding phenology and performance of tropical seabirds in the eastern Indian Ocean

We compared 20 yr of seabird breeding data with oceanographic variables (sea level, sea-surface temperature) and a climate index (Southern Oscillation Index; SOI) for the lesser noddy Anous tenuirostris, brown noddy A. stolidus, sooty tern Onychoprion fuscata and wedge- tailed shearwater Ardenna pacifica at the Houtman Abrolhos, eastern Indian Ocean. We found that timing of breeding and performance of these species is related to climate variability, mediated by oceanographic conditions within the eastern boundary Leeuwin Current (LC). The 3 migratory species have breeding parameters which are correlated with sea level and the SOI, while the first egg date of the resident lesser noddy is correlated with SST during their pre-breeding phase. There was poor breeding performance for each species during El Nino Southern Oscillation (ENSO) conditions; moreover, poor breeding success was recorded for all species outside of (ENSO events in the latter years of the study. In addition, breeding was delayed for all species dur- ing the time of the present study. The environmental conditions contributing to this appear to be fewer years of strong LC flow with associated high sea levels, warmer SSTs, stronger eddy energy and increased productivity. Migratory seabird species breeding at this location appear less able to respond to climate variability — and its influence upon prey availability — than the resident spe- cies. It is suggested that the resident lesser noddy may have an advantage due to its response to a localised environmental cue, SST, in the pre-breeding phase, which may be correlated with prey availability in the waters surrounding the Houtman Abrolhos.

Regional-scale benthic monitoring for ecosystem-based fisheries management (EBFM) using an autonomous underwater vehicle (AUV)

Abstract Smale, D. A., Kendrick, G. A., Harvey, E. S., Langlois, T. J., Hovey, R. K., Van Niel, K. P., Waddington, K. I., Bellchambers, L. M., Pember, M. B., Babcock, R. C., Vanderklift, M. A., Thomson, D. P., Jakuba, M. V., Pizarro, O., and Williams, S. B. 2012. Regional-scale benthic monitoring for ecosystem-based fisheries management (EBFM) using an autonomous underwater vehicle (AUV). – ICES Journal of Marine Science, 69: 1108–1118. Monitoring marine habitats and biodiversity is critical for understanding ecological processes, conserving natural resources, and achieving ecosystem-based fisheries management (EBFM). Here, we describe the application of autonomous underwater vehicle (AUV) technology to conduct ongoing monitoring of benthic habitats at two key locations in Western Australia. Benthic assemblages on rocky reefs were sampled with an AUV, which captured &gt;200 000 geo-referenced images. Surveys were designed to obtain 100% coverage of 25 × 25 m patches of benthic habitat. In 2010, multiple patches were surveyed at 15–40-m depths at three reference sites at the Houtman Abrolhos Islands and at six reference sites at Rottnest Island. The following year, repeat surveys of the same geo-referenced patches were conducted. Benthic assemblages at the Houtman Abrolhos Islands were varied in that one reference site was dominated by hard corals, whereas the other two were macroalgae dominated. Conversely, assemblages at Rottnest Island were dominated by the kelp Ecklonia radiata. The AUV resurveyed each patch with high precision and demonstrated adequate power to detect change. Repeated observations at the reference sites will track natural variability in benthic habitat structure, which in turn will facilitate the detection of ecological change and ultimately feed back into EBFM processes.

FORAMINIFER-BASED CORAL REEF HEALTH ASSESSMENT FOR SOUTHWESTERN ATLANTIC OFFSHORE ARCHIPELAGOS, BRAZIL

Benthic foraminiferal assemblages can indicate the ecological status of coral-reef ecosystems. Their functional groups have been used to calculate the previously published FORAM Index (FI), which is based on total counts (living and dead) to indicate whether an environment is suitable to support prolific calcification by organisms that are dependent upon algal endosymbionts. Sediment was sampled from the Archipelago of Fernando de Noronha and the Abrolhos Archipelago and Parcel, which harbor important coral reef communities off the NE and E coasts of Brazil. Quantifying live specimens and taphonomic features of Amphistegina spp., along with the FI in 2005 and monitoring of the percentage of coral cover from 2002–2009, provided an assessment of coral reef health, which was mapped for both areas. Results indicated that FI was good (>4) in half of the sampled stations, but no living Amphistegina was found in the Abrolhos Archipelago and Parcel, possibly indicating recently unfavorable conditions there. These findings suggest that palimpsest sediment can disguise FI so that, in some cases, the index fails to correlate with coral cover. A more realistic approach can be obtained by using the living counts of Amphistegina and their taphonomy to augment the ecological results from the FI.

Ecological observations associated with an anomalous warming event at the Houtman Abrolhos Islands, Western Australia

Ecological observations associated with an anomalous warming event at the Houtman Abrolhos Islands, Western Australia

Modelling the potential transport of tropical fish larvae in the Leeuwin Current

Application of an individual-based particle tracking model to the migration of tropical fish larvae along the continental shelf between the Houtman Abrolhos Islands and Rottnest Island (Western Australia) has shown that there is potential for the southwards advection of passive particles/larvae in the Leeuwin Current system throughout the year. However, seasonal variations in the prevailing wind field result in corresponding seasonal changes in the surface current flow (both alongshore and cross-shelf) on the continental shelf, leading to a pulse of modelled particles arriving at Rottnest Island during the autumn months. This matches, within a month, the observed April/May peak in annual recruitment of 2 species of damselfish ( Abudefduf sexfasciatus and A. vaigiensis), at the time when the Leeuwin Current is strengthening. It is assumed that the larvae are in the uppermost 20 m of the water column and that there are no vertical diurnal movements. The model has a 10 km grid spacing, and so can resolve some of the current gradients across the continental shelf. Comparison of the modelled near-surface currents with ADCP measurements at 2 current mooring sites as well as with a broader range of historical current measurements off south-western Australia indicates that the alongshore net transport is reasonably well reproduced by the model, whereas agreement with the cross-shelf flow is not as good (this may be partly attributed to the paucity of high-quality near-surface current measurements in the area of study). Because of limitations in our knowledge of the swimming ability, choice of swimming direction and habitat selection of larval fish, as well as the inability of the model to reproduce the small-scale circulation around Rottnest Island, the swimming capacity of the late-stage larval fish is not specifically included; they are considered as potential settlers once they have reached within 20 km of the Island. The observed inter-annual variability in recruitment is not as well matched by the model as is the seasonal pattern, but this is almost certainly due to uncertainties in biological factors such as spawning strength, food and predation en route, which are not known. The modelled results are also applied to a more general discussion of the transport of eggs and larvae of commercial fish and invertebrate species on the Western Australian continental shelf, and it is shown that the seasonality and position on the shelf of the spawning may play a large role in the movement (and hence survival and ultimate recruitment) of different species.

Genetic consequences of isolation: island tammar wallaby (Macropus eugenii) populations and the conservation of threatened species

Isolation and restricted gene flow can lead to genetic deterioration in populations. Populations of many species are increasingly becoming fragmented due to human impacts and active management is required to prevent further extinctions. Islands provide an ideal location to protect species from many mainland threatening processes such as habitat loss and fragmentation, disease and competition/predation from introduced species. However their isolation and small population size renders them prone to loss of genetic diversity and to inbreeding. This study examined two endemic and one introduced population of tammar wallaby (Macropus eugenii) on three islands in the Houtman Abrolhos Archipelago, Western Australia: East Wallabi (EWI), West Wallabi (WWI) and North Islands (NI). Nine autosomal and four Y-linked microsatellite loci, and sequence data from the mitochondrial DNA (mtDNA) control region were used to examine the impact of long-term isolation (EWI and WWI) and small founder size (NI) on genetic diversity and inbreeding. This study found all three populations had low genetic diversity, high levels of effective inbreeding and increased frequency of morphological abnormalities. Isolation has also led to significant inter-population genetic differentiation. These results highlight the importance of incorporating genetic management strategies when utilising islands as refuges for declining mainland populations.

Declines in the abundance of coral trout ( Plectropomus leopardus) in areas closed to fishing at the Houtman Abrolhos Islands, Western Australia

This study aimed to assess temporal trends in the abundance and size of the tropical coral trout, Plectropomus leopardus (Lacepède, 1802), in areas open and closed to fishing at the Houtman Abrolhos Islands. Baited remote underwater stereo-video systems (stereo BRUVs) were used to conduct surveys from 2005 to 2009 from shallow and deep sites across four geographically-separated groups of islands. A total of 1542 P. leopardus were observed from 77% of stereo BRUV deployments with an average abundance of 2.35 ± 0.1 SE per deployment. The lengths of 1238 individuals were measured, with sizes ranging from 118.2 to 727 mm. At commencement of the study in 2005, there were 65% more P. leopardus in areas open vs. closed to fishing. From 2005 to 2009, however, abundances fell by 50% in areas closed to fishing, such that abundances were then similar between areas open and closed to fishing. Relative abundance changed very little in fished locations throughout the course of the study, despite the implementation of fisheries restrictions on other iconic species that may have increased fishing effort on P. leopardus. In areas closed to fishing 12–32% of P. leopardus measured over the five years of the study (average of 25%) were larger than the minimum legal size for retention of 450 mm total length. Much fewer were larger than legal size in areas open to fishing (6–15%, average of 11%). Illegal fishing is considered to be the primary cause of the decline in abundance of P. leopardus inside closed area boundaries.

Human skeletal remains from a multiple burial associated with the mutiny of the VOC Retourschip Batavia, 1629

ABSTRACTOn 4 June 1629, the Verenigde Oostindische Compagnie (VOC) Retourschip Batavia wrecked on Morning Reef in the Houtman Abrolhos, approximately 65 km off the Western Australian coast. The macabre events that followed the wrecking saw more than 100 individuals murdered over a three‐month period by mutineers attempting to establish control of the surviving crew and passengers. The mutineers, however, never realised their ultimate objective of hijacking the anticipated rescue ship, and most were instead duly executed in the Abrolhos. Cultural and physical material directly associated with the Batavia mutiny has since been recovered, primarily from Beacon Island, which was the focal area of the mutinous attempts to establish control.Between 1960 and 1964, four individual burials were recovered on Beacon Island; a further six individuals were recovered from a multiple grave that was excavated in stages between 1994 and 2001. The focus of the present study, however, is to briefly describe the skeletal remains of the multiple burial individuals only, including their demographics (sex, age and stature) and descriptions of potential palaeopathology (trauma, nutritional deficiencies and disease). Osteological analyses indicated an unbalanced sex ratio in favour of males; the age at death distribution ranges from about 8 months to no older than 35–49 years. It appears that prior to their untimely demise, the multiple burial individuals were mostly healthy, with relatively little evidence of disease, illness or ante‐mortem trauma. Copyright © 2011 John Wiley &amp; Sons, Ltd.

Fosfatização de solos e evolução da paisagem no arquipélago de Abrolhos, BA

A atividade da avifauna nos ecossistemas terrestres imprime profundas alterações químicas e mineralógicas nos substratos minerais. O objetivo do presente trabalho é investigar os impactos da atividade da avifauna na evolução da paisagem do arquipélago de Abrolhos através do estudo da distribuição espacial dos solos e suas características químicas, com ênfase na fosfatização. Foram estudados dez perfis de solos representativos das principais unidades de paisagem do arquipélago. Com base em observação de campo e interpretação de carta náutica da Marinha do Brasil (n. 1311), em escala 1:100.000, foi produzido o mapa de solos das ilhas. A presença generalizada de solos fortemente ornitogênicos, em áreas sem nidificação atual ou com fraca nidificação, indica uma ocupação pretérita por aves bem mais ampla que a atual. Alguns solos estudados em Abrolhos são de difícil classificação e refletem influência marcante da avifauna, atual ou pretérita.