Environmental DNA (eDNA) sequencing has emerged as a valuable tool for biodiversity surveys, allowing identification of taxa that may be missed by more traditional methods. Deep-sea corals, while increasingly recognized as a valuable source of habitat in the deep-ocean, have traditionally been challenging to survey. Obstacles to traditional visual surveys of these animals include the expense and complexity inherent to working in the deep marine environment, as well as the existing taxonomic uncertainty and morphological variation which can make deep-sea octocorals difficult to identify visually to the species level. This study tests an eDNA protocol for identification of deep-sea octocorals from water samples collected during the E/V Nautilus 2016 cruise season. Using this protocol, we were able to sequence eDNA from octocorals, and use these data along with image data collected during the cruise to identify taxa to the species level in a variety of habitats. eDNA sampling has the potential to complement traditional deep-sea coral surveys by overcoming the difficulty in visually identifying deep-sea octocorals and characterizing their diversity.
Knowledge of aquaculture–environment interactions is essential for the development of a sustainable aquaculture industry and efficient marine spatial planning. The effects of fish and shellfish farming on sessile wild populations, particularly infauna, have been studied intensively. Mobile fauna, including crustaceans, fish, birds and marine mammals, also interact with aquaculture operations, but the interactions are more complex and these animals may be attracted to (attraction) or show an aversion to (repulsion) farm operations with various degrees of effects. This review outlines the main mechanisms and effects of attraction and repulsion of wild animals to/from marine finfish cage and bivalve aquaculture, with a focus on effects on fisheries-related species. Effects considered in this review include those related to the provision of physical structure (farm infrastructure acting as fish aggregating devices (FADs) or artificial reefs (ARs), the provision of food (e.g. farmed animals, waste feed and faeces, fouling organisms associated with farm structures) and some farm activities (e.g. boating, cleaning). The reviews show that the distribution of mobile organisms associated with farming structures varies over various spatial (vertical and horizontal) and temporal scales (season, feeding time, day/night period). Attraction/repulsion mechanisms have a variety of direct and indirect effects on wild organisms at the level of individuals and populations and may have implication for the management of fisheries species and the ecosystem in the context of marine spatial planning. This review revealed considerable uncertainties regarding the long-term and ecosystem-wide consequences of these interactions. The use of modelling may help better understand consequences, but long-term studies are necessary to better elucidate effects.
Historically sharks have been seen either as a source of income through harvesting, or as a nuisance and danger. The economic value of sharks has traditionally been measured as the total value of sharks caught for liver oil, fins, or meat for consumption. Sharks have also been killed to near extinction in cases where they were seen as a threat to fisheries on other species. This is illustrated by the mass extermination of Basking Sharks (Cetorhinus maximus) in British Columbia. They were seen as a nuisance to fishermen as they got entangled in gill nets during the salmon fishing season. However with the development of the SCUBA diving industry, and ecotourism in general, increased awareness of the role sharks play in marine ecosystems has resulted in changes in how they are perceived and utilized. Despite an ongoing harvest of sharks such as the North Pacific Spiny Dogfish (Squalus suckleyi), sharks now generate economic value through SCUBA diving enthusiasts who travel the globe to see, swim with, and photograph them. The use of digital cameras and other digital media has brought sharks into households around the world and increased awareness of the conservation issues facing many species. This renewed appreciation has led to a better understanding of sharks by the public, resulting in advocates calling for better protections and conservation. In particular, a growing part of the SCUBA diving community wants to contribute to conservation and research projects, which has led to participation in citizen science projects. These projects provide scientific data but also gain ground as ecotourism activities, thus adding to both economic value of tourism and conservation efforts.
In the 21st century, aquaculture is generally characterized as a foe to conservation efforts. Yet, much has changed in the two seemingly disparate practices over the last two decades, motivating an updated evaluation of the scientific evidence for how aquaculture currently impacts conservation, as well as prospects for further alignment and research. Here we present a new perspective on conservation aquaculture, which we redefine as “the use of human cultivation of an aquatic organism for the planned management and protection of a natural resource.” Looking across scales of conservation aquaculture that include single species to ecosystem level benefits (and limitations), we highlight ways aquaculture has historically, and is currently being integrated into conservation (e.g., habitat restoration of oyster beds) and areas that could be improved for the protection of critical species and habitats (e.g., aquarium trade of coral reef species). With a more strategic focus, there appears to be notable conservation aquaculture potential via the cultivation of species for harvest that could provide wild harvest alleviation through replacement or supplement – particularly for over-exploited species – and/or ecosystem services, such as improved water quality and reduction in greenhouse gas emissions. Given that aquaculture is the fastest growing food industry on the planet, aligning farming practices with conservation objectives is particularly pressing to ensure that growth happens in the service of conservation in the most effective and sustainable way possible. The sheer potential of conservation aquaculture suggests a tale of redemption for aquaculture and opportunity for conservationists to bring in a new age of collaborative practices to address global issues.
The tremendous increases in production of plastic materials has led to an accumulation of plastic pollution worldwide. Many studies have addressed the physical effects of large-sized plastics on organisms, whereas few have focused on plastic nanoparticles, despite their distinct chemical, physical and mechanical properties. Hence our understanding of their effects on ecosystem function, behaviour and metabolism of organisms remains elusive. Here we demonstrate that plastic nanoparticles reduce survival of aquatic zooplankton and penetrate the blood-to-brain barrier in fish and cause behavioural disorders. Hence, for the first time, we uncover direct interactions between plastic nanoparticles and brain tissue, which is the likely mechanism behind the observed behavioural disorders in the top consumer. In a broader perspective, our findings demonstrate that plastic nanoparticles are transferred up through a food chain, enter the brain of the top consumer and affect its behaviour, thereby severely disrupting the function of natural ecosystems.
The Clarion-Clipperton Zone (CCZ) in the East Pacific is a vast region targeted for deep-sea mineral exploration, for which there are almost no published taxonomic data. Here we describe Plenaster craigigen. nov. sp. nov. from depths of ∼4000 m in the eastern CCZ polymetallic nodule province. Despite over 40 years of intense exploration in the area, we reveal that P. craigi sp. nov. is the most abundant sponge and the most common metazoan encrusting on nodules in our study area at the eastern CCZ. It has a mean abundance of 15.3 ± 8.9 individuals per m2 across 11 stations in a 30 × 30 km study site nested within the Singapore exploration area. The white encrusting sponge is filled with spheroxyasters with occasional styles protruding the surface. Plenaster craigi sp. nov. is morphologically similar to genera from three different families in two orders: Timea (Timeidae; Tethyida); Hemiasterella and Leptosastra(Hemiasterellidae; Tethyida); and Paratimea (Stelligeridae; Axinellida). However, based on the molecular (COI and 28S) phylogenetic trees generated in this study, P. craigi sp. nov. was located in the Order Axinellida and appeared to be distant to Timea, Hemiasterella, Leptosastra, and Paratimea. We propose a new genus for our material to be placed provisionally in the family Stelligeridae, as it is the only family in the order Axinellida whose members possess euasters. This provisional placement may change when sequences of the type specimens of these genera and advanced phylogenetic reconstruction methods become available in the future. However, we have shown clearly that Plenaster gen. nov. is unique and distinct from all currently known taxa. Plenaster craigi sp. nov. being an abundant metazoan encrusting on nodule and easily identified filter-feeding animal is a potentially indicator species for future mining impacts in the eastern CCZ, and possibly across the entire CCZ.
The present study reports the genetic damage and the concentrations of trace metals and total petroleum hydrocarbons prevailing in natural populations of an edible fish, Arius arius in different seasons along the coast of Goa, India as an indicator of the pollution status of coastal water. Fish were collected from a suspected polluted site and a reference site in the pre-monsoon, monsoon and post-monsoon seasons. Physico-chemical parameters as well as the concentrations of total petroleum hydrocarbons (TPH) and trace metals in the water and sediment as well as the tissues of fish collected from these sites were recorded. The genotoxicity status of the fish was assessed employing the micronucleus test and comet assay. A positive correlation (p<0.001) was observed between the tail DNA and micronuclei in all the fish collected. Multiple regression analysis revealed that tissue and environmental pollutant concentrations and genotoxicity were positively associated and higher in the tissues of the fish collected from the polluted site. Pollution indicators and genotoxicity tests, combined with other physiological or biochemical parameters represent an essential integrated approach for efficient monitoring of aquatic ecosystems in Goa.
The functional composition of local assemblages is hypothesized to be controlled by hierarchical environmental filters, whereby the importance of different abiotic and biotic factors varies across both spatial scales and the different dimensions of functional diversity. We examine scale dependence in functional diversity–environment relationships with the ultimate aim of advancing models that predict the response of functional diversity to global change.
Coral reefs surrounding 23 minimally disturbed central-western Pacific islands.
Major taxa studied
Coral reef fishes.
We surveyed 1,423 reef sites using a standardized monitoring protocol and classified the 547 taxa encountered based on traits related to resource use, body size and behaviour. For each fish community, we calculated species richness and three metrics of functional diversity: functional richness, functional redundancy and functional evenness. We then built nested models at three spatial scales to evaluate the predictive power of environmental conditions over each component of functional diversity.
Climatic variables (e.g., primary productivity) and geomorphic context (e.g., bathymetric slope) were more important in predicting functional diversity at coarse spatial scales. In contrast, local measures of habitat quality, including benthic complexity, depth and hard coral cover, were generally most important at finer scales. All diversity metrics were better predicted at coarser scales, but which predictors were important varied among metrics.
The observed scale dependence in environmental predictors of functional diversity generally matches models of hierarchical filters on functional community assembly. Contrary to expectation, however, functional evenness and functional redundancy, which incorporate information on biomass distributions, were not better predicted at finer spatial scales. Instead, broad-scale variation in environmental variables was most important in predicting all components of functional diversity. Furthermore, the distinct responses of each functional diversity metric to environmental variation indicate that each measures a unique dimension of reef-fish diversity, and environmental change may affect each differently.
In 2010, the Marine Education Center collaborated with the Center for Fisheries Research and Development's Shark Research Program to design an educational program that combined research experiences and educational opportunities for teenage audiences. This program, Shark Fest, educates students about the sharks of the Mississippi Sound and engages them in scientific studies of shark populations and movements. This program has reached 398 participants in grades 7–12. During the program, students assist in conducting a population survey using a 152.4-m (500-ft) bottom longline with 50 hooks and fishing with a rod-and-reel. Students measure, weigh, determine sex, and identify to species all captured sharks, and tag those in good condition prior to release. Program participants also conduct water-quality sampling (salinity, temperature, dissolved oxygen, and water clarity) at each sample site for addition to the database. Students take a pre-test and post-test to assess the level of knowledge gained during the program. Results of a paired-sample t-test on 2015 pre-test and post-test data reflected a significant difference in pre-test (mean = 6.16, SD = 2.36) and post-test (mean = 8.54, SD = 1.93) scores (t = -9.172, P < 0.0001), indicating an increase in content knowledge. Written and verbal post-participation assessments also highlighted a positive student experience. We conducted opportunistic interviews with several students 4 years after they were in the program and found evidence of retained knowledge along with positive overall impressions. Some participants stated that the experience influenced their career pursuits.
Field data are still recorded on paper in many worldwide beach surveys of nesting marine turtles. The data must be subsequently transferred into an electronic database, and this can introduce errors in the dataset. To minimize such errors, the “Turtles” software was developed and piloted to record field data by one software user accompanying one Tortuguero in Akumal beaches, Quintana Roo, Mexico, from June 1st to July 31st during the night patrols. Comparisons were made between exported data from the software with the paper forms entered into a database (henceforth traditional). Preliminary assessment indicated that the software user tended to record a greater amount of metrics (i.e., an average of 18.3 fields ± 5.4 sd vs. 8.6 fields ± 2.1 sd recorded by the traditional method). The traditional method introduce three types of “errors” into a dataset: missing values in relevant fields (40.1%), different answers for the same value (9.8%), and inconsistent data (0.9%). Only 5.8% of these (missing values) were found with the software methodology. Although only tested by a single user, the software may suggest increased efficacy and warrants further examination to accurately assess the merit of replacing traditional methods of data recording for beach monitoring programmes.