Julia L.Y. Spaet

University of Cambridge | Cam · Department of Zoology

Given the global concern about the status of elasmobranch fishes, the paucity of information on elasmobranchs in the Red Sea is worrisome. Management of elasmobranchs in areas other than the Red Sea has been helped by research on population ecology, reproductive biology and resource partitioning, subjects that are virtually absent in the Red Sea el...

Context Currently, little information exists describing the population structure of great hammerhead sharks (Sphyrna mokarran) in Australian waters. Aims This study used single nucleotide polymorphisms to investigate fine-scale population structure in S. mokarran across the Indo-Pacific. Methods DNA was extracted from 235 individuals across six Aus...

The bowmouth guitarfish ( Rhina ancylostomus ) is a unique and relatively understudied species of wedgefish with a distribution spanning the Indo-Pacific Oceans. Due to targeted and bycatch fisheries, this species is experiencing serious declines across its range. It is now considered among the most threatened species of elasmobranch. Despite this,...

A global survey of coral reefs reveals that overfishing is driving resident shark species toward extinction, causing diversity deficits in reef elasmobranch (shark and ray) assemblages. Our species level analysis revealed global declines of 60 to 73% for five common resident reef shark species and that individual shark species were not detected at...

A global survey of coral reefs reveals that overfishing is driving resident shark species toward extinction, causing diversity deficits in reef elasmobranch (shark and ray) assemblages. Our species-level analysis revealed global declines of 60 to 73% for five common resident reef shark species and that individual shark species were not detected at...

The Great Hammerhead Shark, Sphyrna mokarran, is critically endangered around the world. The overwhelming majority of their records are of animals killed, quartered or captured by fishermen, which limit our understanding on its biology and conservation. For the first time, we report on the S. mokarran occurrence in the State of Paraíba, Northeaster...

In the original publication [...]

Knowledge of the 3-dimensional space use of large marine predators is central to our understanding of ecosystem dynamics and for the development of management recommendations. Horizontal movements of white sharks, Carcharodon carcharias, in eastern Australian and New Zealand waters have been relatively well studied, yet vertical habitat use is less...

In eastern Australia, white sharks (Carcharodon carcharias) are targeted in shark control programs, yet the movement of subadults and adults of the eastern Australasian population is poorly understood. To investigate horizontal and vertical movement and habitat use in this region, MiniPAT pop-up satellite archival tags were deployed on three larger...

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first globa...

Effective conservation strategies are founded by baseline information on abundance and diversity estimates. Method choice can influence the success of baseline surveys as method performance is variable and needs to be selected based on habitat and taxa. Here, we assess the suitability of unoccupied aerial vehicle (UAV) surveys, specifically multi-r...

Increasing fishing pressure has negatively impacted elasmobranch populations globally. Despite high levels of historical and current fishing pressure, the Bay of Bengal region remains data‐poor. Focusing on Bangladesh, we conducted a socio‐ecological study to characterize elasmobranch fisheries and evaluate their impact on threatened species. The r...

Trade in elasmobranch products is a circum-global practice negatively impacting elasmobranch populations. Although Asia is at the centre of the shark fin trade, countries like Bangladesh, remain data-poor regarding trade dynamics. In the Bay of Bengal region, Bangladesh has a long-standing history of producing and trading products from vulnerable a...

Recognizing the imperative to evaluate species recovery and conservation impact, in 2012 the International Union for Conservation of Nature (IUCN) called for development of a “Green List of Species” (now the IUCN Green Status of Species). A draft Green Status framework for assessing species’ progress toward recovery, published in 2018, proposed 2 s...

Inferences regarding animal presence from passive acoustic receiver arrays are driven by the spatial configuration of receivers. Large, dense arrays provide more information, but maintenance of multiple receivers is costly. Configuring acoustic receiver arrays to maximise coverage while minimising cost is therefore paramount. This study used data f...

Habitat use and movement patterns of tiger sharks (Galeocerdo cuvier) in eastern Australian waters. Understanding the movement of marine predators is vital for effective conservation and management. Despite being targeted by shark control programs, the tiger shark, Galeocerdo cuvier, is poorly studied off eastern Australia. To investigate the horiz...

Understanding and predicting the distribution of organisms in heterogeneous envi- ronments is a fundamental ecological question and a requirement for sound management. To implement effective conservation strategies for white shark Carcharodon carcharias populations, it is imperative to define drivers of their movement and occurrence patterns and to...

In Australian and New Zealand waters, current knowledge on white shark (Carcharodon carcharias) movement ecology is based on individual tracking studies using relatively small numbers of tags. These studies describe a species that occupies highly variable and complex habitats. However, uncertainty remains as to whether the proposed movement pattern...

The evolutionary origins of sharks date back more than 400 million years, ranking them among the oldest extant taxa of vertebrates. Sharks are found throughout the world’s oceans, inhabiting coastal waters and open seas, from the surface to depths of 3000 m. Of the more than 500 shark species described to date, only 29 are found in the Red Sea. In...

The increase in demand for shark meat and fins has placed shark populations worldwide under high fishing pressure. In the Arabian region, the spot-tail shark Carcharhinus sorrah and the Blacktip shark Carcharhinus limbatus are among the most exploited species. In this study, we investigated the population genetic structure of C. sorrah (n = 327) al...

The extinction risk of sharks, rays and chimaeras is higher than that for most other vertebrates due to low intrinsic population growth rates of many species and the fishing intensity they face. The Arabian Sea and adjacent waters border some of the most important chondrichthyan fishing and trading nations globally, yet there has been no previous a...

Background: Despite being frequently landed in fish markets along the Saudi Arabian Red Sea coast, information regarding fundamental biology of the Scalloped hammerhead shark (Sphyrna lewini) in this region is scarce. Satellite telemetry studies can generate important data on life history, describe critical habitats, and ultimately redefine managem...

Background Despite being frequently landed in fish markets along the Saudi Arabian Red Sea coast, information regarding fundamental biology of the Scalloped hammerhead shark (Sphyrna lewini) in this region is scarce. Satellite telemetry studies can generate important data on life history, describe critical habitats, and ultimately redefine manageme...

The Arabian Seas Region plays an important role in the global landings and trade of sharks and rays. The United Arab Emirates (UAE) and Yemen, two countries with stark socioeconomic differences, serve as major regional trade hubs for shark and ray products and four countries (Oman, Pakistan, UAE and Yemen) supply nearly 11% of dried fin exports to...

Mercury (Hg) exposure poses a threat to both fish and human health. Sharks are known to bioaccumulate Hg, however, little is known regarding how Hg is distributed between different tissue groups (e.g. muscle regions, organs). Here we evaluated total mercury (THg) concentrations from eight muscle regions, four fins (first dorsal, left and right pect...

Shark-cetacean aggregations and associations of false kill- er whales (Pseudorca crassidens) with other cetaceans have been reported previously (e.g., Heithaus 2001; Baird et al. 2008). However, this is the first description of non- aggressive associations of P. crassidens with non- cetaceans.

Eighteen microsatellite loci were developed for the silky shark Carcharhinus falciformis and screened across a total of 53 individuals from the western Atlantic Ocean, Eastern Tropical Pacific Ocean, and Red Sea. The number of alleles per locus ranged from 3 to 19, observed heterozygosity ranged from 0.158 to 0.917, and the probability of identity...

The northwestern Indian Ocean harbors a number of larger marine vertebrate taxa that warrant the investigation of genetic population structure given remarkable spatial heterogeneity in biological characteristics such as distribution, behavior, and morphology. Here, we investigate the genetic population structure of four commercially exploited shark...

sampling includes 4 widely separated locations in the Indo-Pacific and 11 islands in French Polynesia with different levels of coastal development. 14 microsatellite loci were analysed for samples from all locations and 2 mitochondrial DNA fragments, the control region and cytochrome b, were examined for 10 locations. For microsatellites, genetic d...

The Red Sea has long been recognized as a region of high biodiversity and endemism. Despite this diversity and early history of scientific work, our understanding of the ecology of coral reefs in the Red Sea has lagged behind that of other large coral reef systems. We carried out a quantitative assessment of ISI-listed research published from the R...

Long-line surveys, conducted over the past 24 years from Bimini, Bahamas reveal a decline of 83% in the number of lemon sharks caught annually compared with catches for the same period 20 years ago. We suggest that resident lemon sharks might have learned to avoid long-line equipment based on their ability to detect electric fields. We tested wheth...