J. Jed Brown’s research while affiliated with Qatar University and other places

Many shark populations are in decline around the world, with severe ecological and economic consequences. Fisheries management and marine protected areas (MPAs) have both been heralded as solutions. However, the effectiveness of MPAs alone is questionable, particularly for globally threatened sharks and rays (‘elasmobranchs’), with little known about how fisheries management and MPAs interact to conserve these species. Here we use a dedicated global survey of coral reef elasmobranchs to assess 66 fully protected areas embedded within a range of fisheries management regimes across 36 countries. We show that conservation benefits were primarily for reef-associated sharks, which were twice as abundant in fully protected areas compared with areas open to fishing. Conservation benefits were greatest in large protected areas that incorporate distinct reefs. However, the same benefits were not evident for rays or wide-ranging sharks that are both economically and ecologically important while also threatened with extinction. We show that conservation benefits from fully protected areas are close to doubled when embedded within areas of effective fisheries management, highlighting the importance of a mixed management approach of both effective fisheries management and well-designed fully protected areas to conserve tropical elasmobranch assemblages globally.

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 34 to 47% of surveyed reefs. As reefs become more shark-depleted, rays begin to dominate assemblages. Shark-dominated assemblages persist in wealthy nations with strong governance and in highly protected areas, whereas poverty, weak governance, and a lack of shark management are associated with depauperate assemblages mainly composed of rays. Without action to address these diversity deficits, loss of ecological function and ecosystem services will increasingly affect human communities.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Halophyte farming seems to be a promising alternative to conventional agriculture under marginal environments, since it does not compete with dwindling fresh water and land resources. For this purpose halophytic species need to be domesticated to serve as a “crop” plant. Field evaluation of six Salicornia bigelovii Torr. populations (LA, GA, MI, FL2, SP, FL1) was conducted in 2012–2013 in the United Arab Emirates applying two irrigation treatments: brackish groundwater (20 dSm−1) and seawater (55 dSm−1) to examine their growth performance taking into account 24 plant characteristics, biomass, seed yield parameters, and growth stages attributes. The experimental results indicated that S. bigelovii populations were highly variable for the majority of traits. Irrigation with seawater negatively influenced the agronomic performance of S. bigelovii populations compared to groundwater. SP, MI, and GA populations received higher values for almost all characteristics observed, as compared to LA, FL1, and FL2 populations especially under groundwater treatment. Seawater extended the duration of growth cycle for all Salicornia populations compared to groundwater irrigation. The outcomes clearly indicated that the salinity level had an impact on S. bigelovii populations’ performance and yield potential. It is suggested that screening should be evaluated under both optimum and full-strength saline water to optimize biomass and seed production. The existing genotypes could be further improved through breeding taking into account spike characteristics and days to flowering as revealed by path analysis. Combining suitable germplasm with proper agronomic practices, there is a big potential to develop this halophytic species plantations for economically viable production systems in hot and dry regions.

Decades of overexploitation have devastated shark populations, leaving considerable doubt as to their ecological status1,2. Yet much of what is known about sharks has been inferred from catch records in industrial fisheries, whereas far less information is available about sharks that live in coastal habitats³. Here we address this knowledge gap using data from more than 15,000 standardized baited remote underwater video stations that were deployed on 371 reefs in 58 nations to estimate the conservation status of reef sharks globally. Our results reveal the profound impact that fishing has had on reef shark populations: we observed no sharks on almost 20% of the surveyed reefs. Reef sharks were almost completely absent from reefs in several nations, and shark depletion was strongly related to socio-economic conditions such as the size and proximity of the nearest market, poor governance and the density of the human population. However, opportunities for the conservation of reef sharks remain: shark sanctuaries, closed areas, catch limits and an absence of gillnets and longlines were associated with a substantially higher relative abundance of reef sharks. These results reveal several policy pathways for the restoration and management of reef shark populations, from direct top-down management of fishing to indirect improvement of governance conditions. Reef shark populations will only have a high chance of recovery by engaging key socio-economic aspects of tropical fisheries.

With the growing criticisms of using arable land and edible crops to produce first-generation biofuels instead of food for humans, there is an increasing interest in using marginal lands and water sources to grow biofuel feedstocks to produce second-generation biofuels. One possible way forward would be to use seawater or other high-salinity water to grow salt-tolerant plants (halophytes). Halophytes have the potential to grow and produce lignocellulosic biomass and oilseeds on high-salinity water such as seawater. No halophyte bioenergy crops have been domesticated to date. However many of the species that have been investigated have shown good characteristics, both in the composition and yield of the straw biomass and in the oilseeds to produce good-quality lignocellulosic ethanol, biodiesel, or other forms of bioenergy and compare favorably to conventional biofuel feedstocks. Here the potential of using halophytes as biofuel feedstocks is reviewed, and the various considerations that would need to be taken into account before embarking on any commercial effort to produce biofuels from halophytes are described.

One way to encourage agricultural self-sufficiency in arid regions is to increase the productivity of conventional freshwater agriculture. Another way is to develop and implement novel strategies and technologies that do not deplete scarce freshwater. Here we describe several options for countries in the Gulf region to increase their agricultural production by taking advantage of a lesser used resource—marginal water. Marginal water can be treated sewage effluent, produced oilfield water, brackish groundwater or seawater. We describe how this resource can be used to grow salt-tolerant forage crops, microalgae and aquaculture crops. Policies needed to implement and/or scale-up such practices are also outlined.

Halophytes constitute an indispensable part of seawater farming systems implemented in coastal areas of desert lands where they do not compete with good quality land and water resources. Salicornia bigelovii is considered one of the most promising halophytic species that will grow in a biosaline context. However, suitable germplasm needs to be identified, domesticated and improved in order to achieve high enough yields to compete economically to conventional crops. In the current study, eleven S. bigelovii Torr. populations were evaluated for 22 growth parameters and irrigated with full-strength seawater (SW≈55 dS/m).The study assessed the adaptability of such plant material under the hot and dry climatic conditions that prevail in the Arabian Peninsula. High variation was observed among S. bigelovii populations for most of the characteristics under study. S. bigelovii genotypes were categorized in four groups based on their growth performance and use: for seed production, green biomass as vegetables for human consumption, and biomass as livestock feed; the fourth category was comprised of those halophytic genotypes that demonstrated poor overall performance. Pearson correlation analysis highlighted positive and negative associations among the growth parameters. Path analysis unveiled some interesting interrelationships among growth parameters that could be used for further selection to increase seed production such as number of seeds per spike, number of branches, days to flowering and duration of seed maturity. Plant height and growth cycle could be selected for biomass improvement. The multivariate statistical analyses applied in this study, i.e. clustering, correlation and path analyses were very effective in classifying S. bigelovii genotypes and revealed interrelationships among growth traits that could be selected towards S. bigelovii improvement in terms of seed and biomass yield.

Suaeda linearis (Ell.) Moq. is a New World temperate, subtropical, and tropical maritime species that typically occurs 1.0–1.5 m above the mean high tide mark. It is a facultative annual that occurs on saturated substrates consisting of unconsolidated sand, shell fragments, and slightly elevated saline clays and sandy clays. Also known as sea blite, it is found in salinity conditions ranging from 10 to 50 parts per thousand. Sexual reproduction is the only mechanism of reproduction. Seed production is prolific and seed banks are well-supplied with this species. Seeds are dimorphic, and germination is high in both full sun and in shaded conditions.