Soft bodies make estimation hard: Correlations among body dimensions and weights of multiple species of sea cucumbers

Tropical sea cucumbers are commonly exploited by small-scale, poorly managed fisheries. A fundamental problem in managing sea cucumber fisheries is the lack of basic knowledge of important life history characteristics for most species. As a result of plastic body dimensions, biological research on this group of animals becomes exceptionally challenging. To improve our understanding of essential biological parameters, we conducted a study to investigate correlations among various body measurements. We analysed a total of 18 sea cucumber species and more than 6600 individuals collected at Scott Reef in the Timor Sea, north-west Australia. We used hierarchical Bayesian errors-in-variables models to specifically take into account measurement errors that are obviously unavoidable. The measures included three types of weights (wet weight, gutted weight and dry weight) and two body dimensions (length and width). The modelling reveals that using both body length and width as independent variables, wet weight increases approximately linearly with body length, but is a power function (~1.6) of body width, although variability exists among species. Dry weight tends to increase more slowly with body length, but has a similar power function of body width. Linear relationships are established between the three types of weights. On average, ~11% of a live specimen and ~16% of a gutted specimen is processed to the commercially traded dry body wall. Our results can be applied to sea cucumbers in other areas and can be useful for data standardisation and size-based fisheries management

Shark-dust: Application of high-throughput DNA sequencing of processing residues for trade monitoring of threatened sharks and rays

Illegal fishing, unregulated bycatch, and market demand for certain products (e.g., fins) are largely responsible for the rapid global decline of shark and ray populations. Controlling trade of endangered species remains difficult due to product variety, taxonomic ambiguity, and trade complexity. The genetic tools traditionally used to identify traded species typically target individual tissue samples, and are time-consuming and/or species-specific. Here, we performed high-throughput sequencing of trace DNA fragments retrieved from dust and scraps left behind by trade activities. We metabarcoded “shark-dust” samples from seven processing plants in the world's biggest shark landing site (Java, Indonesia), and identified 61 shark and ray taxa (representing half of all chondrichthyan orders), more than half of which could not be recovered from tissue samples collected in parallel from the same sites. Importantly, over 80% of shark-dust sequences were found to belong to CITES-listed species. We argue that this approach is likely to become a powerful and cost-effective monitoring tool wherever wildlife is traded

Shark-dust: high-throughput DNA sequencing of processing residues unveils widespread trade in threatened sharks and rays

Illegal fishing, unregulated bycatch, and market demand for certain products (e.g. fins) are largely responsible for the rapid global decline of shark and ray populations. Controlling trade of endangered species remains difficult due to product variety, taxonomic ambiguity and trade complexity. The genetic tools traditionally used to identify traded species typically target individual tissue samples, are time-consuming and/or species-specific. Here, we performed high-throughput sequencing of trace DNA fragments retrieved from dust and scraps left behind by trade activities. We metabarcoded ‘shark-dust’ samples from seven processing plants in the world’s biggest shark landing site (Java, Indonesia), and identified 54 shark and ray taxa (representing half of all chondrichthyan orders), half of which could not be recovered from tissue samples collected in parallel from the same sites. Importantly, over 80% of shark-dust sequences were found to belong to CITES-listed species. We argue that this approach is likely to become a powerful and cost-effective monitoring tool wherever wildlife is traded

Shark and ray trade in and out of Indonesia: Addressing knowledge gaps on the path to sustainability

Indonesian marine resources are among the richest on the planet, sustaining highly diverse fisheries. These fisheries include the largest shark and ray landings in the world, making Indonesia one of the world’s largest exporters of elasmobranch products. Socio-economic and food security considerations pertaining to Indonesian communities add further layers of complexity to the management and conservation of these vulnerable species. This study investigates the elasmobranch trade flows in and out of Indonesia and attempts to examine patterns and drivers of the current scenario. We identify substantial discrepancies between reported landings and declared exports, and between Indonesian exports in elasmobranch fin and meat products and the corresponding figures reported by importing countries. These mismatches are estimated to amount to over $43.6 M and$20.9 M for fins and meat, respectively, for the period between 2012 and 2018. Although the declared exports are likely to be an underestimation because of significant unreported or illegal trading activities, we note that domestic consumption of shark and ray products may also explain these discrepancies. The study also unearths a general scenario of unsystematic data collection and lack of granularity of product terminology, which is inadequate to meet the challenges of over-exploitation, illegal trade and food security in Indonesia. We discuss how to improve data transparency to support trade regulations and governance actions, by improving inspection measures, and conserving elasmobranch populations without neglecting the socio-economic dimension of this complex system

SPARC 2021 - Against all odds : Salford postgraduate annual research conference book of abstracts

Welcome to the Book of Abstracts for the 2021 SPARC conference. Our conference is called “Against All Odds” as we celebrate the achievements of our PGRs and their supervisors, who have continued to excel despite the most challenging circumstances. For this reason, we showcase the work of our PGRs alongside the outstanding supervision that they receive, with our Doctoral School Best Supervisor awards. We also focus on developing resilience and maintaining good mental health in the research environment, supported by exceptional keynote speakers, including our very own Dr Michelle Howarth and Ruby Wax OBE, which makes this year’s conference extra special

Molecular approaches to reduce the illegal trade of shark and ray products in Indonesia

Trade restrictions have been established to counteract the rapid global decline of sharks and rays (hereafter called elasmobranchs), such as controlled species under CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora). This has resulted from high fishing pressure, by-catch and market demand for certain products (e.g. fins). Tackling the illegal trade of endangered species poses enormous challenges for authorities, including taxonomic ambiguity, product variety, logistical issues for inspections and trade flow complexity. Based on extensive trade statistics, we found there was a substantial mismatch between exports of elasmobranch fin and meat products and the corresponding figures reported by importing countries ($43.6 M and$20.9 M for fins and meat, respectively) from the top shark landing country; Indonesia. That may signal illegal trading activities. When key visual identification for shark products disappears, genetics tools may help to improve trade monitoring. Over 579 tissue samples were collected in many locations (export hubs, processing plants, collectors, authority offices and landing sites) across Java Island, Indonesia, which have diverse processing conditions. Portable genetic techniques are urgently required to improve traceability, and we tested a recently developed universal assay (known as FastFish-ID) based on real-time PCR. By combining visual and deep learning assignment methods, we were able to successfully validate the method on 25 out of 28 species, 20 of which were CITES-listed. However, the illicit trade may be concealed from inspection, and that is a challenge for individual tissue-based genetic approaches. The ‘shark-dust’ metabarcoding approach offers an innovative application of metabarcoding to reveal the diversity of sharks being traded only based on the processing residues. This stupendous technique revealed 27 more taxa than individual tissue-based techniques and found that over 80% of the reads belonged to CITES-listed species. We argue that these approaches are likely to become a powerful, cost-effective and applicable monitoring tool wherever marine wildlife is traded globally.Keywords: trade monitoring, conservation, CITES, sharks, rays, lab-on-the-field, portable tool, DNA metabarcoding, environmental DNA, Indonesi

An unlikely partnership: fishers’ participation in a small-scale fishery data collection program in the Timor Sea

Traditional fisheries stock assessment methods and fishery independent surveys are costly and time consuming exercises. However fishers trained in data collection and utilising other skills can reduce costs and improve fishery assessments and management. A data collection program was conducted by Australian and Indonesian scientists with small-scale Indonesian sea cucumber fishers to evaluate the approach and then capture its benefits. The data fishers recorded allowed for the first stock assessment of this trans-boundary fishery during its centuries-long existence at Scott Reef in north-western Australia. The program also included interviews with fishers capturing the social, economic, and demographic aspects of the fishery. Economic inputs to fishing were complemented by fishery revenue data voluntarily submitted when fishers returned to port and sold their catch. Catch data recorded by fishers demonstrated much higher abundances than estimates obtained using standard visual transect methods and accurately reflected the true catch composition. However, they also showed extreme rates of exploitation. Interviews revealed social and economic factors that would be important considerations if management interventions were made. The program’s approach and the time scientists spent on the fishers’ vessels were key ingredients to fishers’ participation and the utility of the results. Despite the program’s achievements the information generated has not led to improved management or had any direct benefits for the participants. Sustaining the program in the longer term requires that its value is better captured

The money side of livelihoods: Economics of an unregulated small-scale Indonesian sea cucumber fishery in the Timor Sea

Fishers from several ethnic groups on islands in eastern Indonesia seasonally fish for sea cucumbers at Scott Reef in Australia's Exclusive Economic Zone in the Timor Sea. Despite evidence suggesting that sea cucumbers are severely over-exploited fishers continue to voyage to the reef. How the traditional fishery operates under this condition and more broadly what economic drivers cause fishers to make the long and arduous voyage is vital to understanding this small-scale fishery and developing appropriate strategies for management. This study is the first to investigate these dynamic livelihood aspects using semi-structured interviews and fishers’ voluntarily recorded data on their catches, costs of fishing and the sales of those catches and income received over a six year period. The study demonstrated that costs, borrowings, and revenues differed between crews, leading to widely varying profits. Nevertheless, every crew that recorded the sale of their catches made a profit. Rapidly appreciating prices for their sea cucumber harvest, predominantly comprising low value species, was critical to maintaining the fishery's profitability. The income earned by some crews and boat owners were far greater than those potentially available to them through other livelihood strategies such as agriculture, coastal fisheries or trade opportunities. This study also suggests the depletion of high value sea cucumber species is ongoing. This Indonesian sea cucumber fishery at Scott Reef illustrates the linkages between stock sustainability, fishers’ livelihood outcomes, and the burgeoning Asian demand for sea cucumbers and the findings can inform the current management discourse on this small-scale transboundary fishery