Eelgrass Beds Research Articles

A Latitudinal Cline in the Taxonomic Structure of Eelgrass Epifaunal Communities is Associated With Plant Genetic Diversity

ABSTRACTAimBiogenic structural complexity increases mobile animal richness and abundance at local, regional and global scales, yet animal taxa vary in their response to complexity. When these taxa also vary functionally, habitat structures favouring certain taxa may have consequences for ecosystem function. We characterised global patterns of epifaunal invertebrates in eelgrass (Zostera marina) beds that varied in structural and genetic composition.LocationNorth America, Europe and Asia.Time Period2014.Major Taxa StudiedPeracarid crustaceans and gastropod molluscs.MethodsWe sampled epifaunal invertebrate communities in 49 eelgrass beds across 37° latitude in two ocean basins concurrently with measurements of eelgrass genetic diversity, structural complexity and other abiotic and biotic environmental variables. We examined how species richness, abundance and community composition varied with latitude and environmental predictors using a random forest approach. We also examined how functional trait composition varied along with community structure.ResultsTotal species richness decreased with latitude, but this was accompanied by a taxonomic shift in dominance from peracarid crustaceans to gastropods, which exhibited different sets of functional traits. Greater eelgrass genetic diversity was strongly correlated with both richness and abundance of peracarids, but less so for gastropods.Main ConclusionsOur results add to a growing body of literature that suggests genetic variation in plant traits influences their associated faunal assemblages via habitat structure. Because peracarids and gastropods exhibited distinct functional traits, our results suggest a tentative indirect link between broad‐scale variation in plant genetic diversity and ecosystem function.

Temperature, sediment resuspension, and salinity drive the prevalence of Vibrio vulnificus in the coastal Baltic Sea

ABSTRACT The number of Vibrio -related infections in humans, e.g., by Vibrio vulnificus , has increased along the coasts of the Baltic Sea. Due to climate change, vibriosis risk is expected to increase. It is, therefore, pertinent to design a strategy for mitigation of the vibriosis threat in the Baltic Sea area, but a prerequisite is to identify the environmental conditions promoting the occurrence of pathogenic Vibrio spp., like V. vulnificus . To address this, we sampled three coastal Baltic sites in Finland, Germany, and Denmark with salinities between 6 and 21 from May to October 2022. The absolute and relative abundances of Vibrio spp. and V. vulnificus in water were compared to environmental conditions, including the presence of the eelgrass Zostera marina , which has been suggested to reduce pathogenic Vibrio species abundance. In the water column, V. vulnificus only occurred at the German station between July and August at salinity 8.1–11.2. Temperature and phosphate (PO 4 3– ) were identified as the most influencing factors for Vibrio spp. and V. vulnificus . The accumulation of Vibrio spp. in the sediment and the co-occurrence with sediment bacteria in the water column indicate that sediment resuspension contributed to V. vulnificus abundance. Interestingly, V. vulnificus co-occurred with specific cyanobacteria taxa, as well as specific bacteria associated with cyanobacteria. Although we found no reduction in Vibrio spp. or V. vulnificus associated with eelgrass beds, our study underscores the importance of extended heatwaves and sediment resuspension, which may elevate the availability of PO 4 3– , for Vibrio species levels at intermediate salinities in the Baltic Sea. IMPORTANCE Elevated sea surface temperatures are increasing the prevalence of pathogenic Vibrio at higher latitudes. The recent increase in Vibrio -related wound infections and deaths along the Baltic coasts is, therefore, of serious health concern. We used culture-independent data generated from three Baltic coastal sites in Denmark, Germany, and Finland from May to October (2022), with a special focus on Vibrio vulnificus , and combined it with environmental data. Our temporal model shows that temperature, combined with sediment resuspension, drives the prevalence of V. vulnificus at intermediate salinities in the coastal Baltic Sea.

Use of Landsat Imagery Time-Series and Random Forests Classifier to Reconstruct Eelgrass Bed Distribution Maps in Eeyou Istchee

The eastern coastline of James Bay is known to have been home to sizeable eelgrass beds (Zostera marina L.) which thrived in the bay’s shallow, subarctic waters. The region was subjected to substantial hydroelectric dams, large fires, and other human activities in the past half-century. To assess the impact of these factors on eelgrass beds, a historical reconstruction of eelgrass bed distribution was performed from images acquired by Landsat-5 Thematic Mapper (TM) in 1988, 1991, and 1996 and images of the Landsat-8 Operational Land Imager (OLI) in 2019. All the images were classified using the Random Forests classifier (RF) and assessed for accuracy each year on a bay-wide scale using an independent field validation dataset. The validation data were extracted from an eelgrass bed map established using aerial photos and field surveys in 1986, 1991, and 1995 and from a field survey in 2019. The overall validation accuracy of the classified images (between 72% and 85%) showed good agreement with the other datasets for most locations, providing reassurance about the reliability of the research. This makes it possible to use satellite imagery to detect past changes to eelgrass distribution within a bay. The classified images of 1988 and 1996 were also compared to aerial photos taken in years close to each other at ten sites to determine their ability to assess small eelgrass beds’ shape and presence. Such a comparison revealed that the classified images accurately portrayed eelgrass distribution even at finer scales.

Modelling water temperature dynamics for eelgrass (Zostera marina) areas in the nearshore Scotian Shelf

Water temperature is an important environmental factor for many ecological processes in coastal ecosystems. Here, we study water temperature dynamics at a set of study sites on the Atlantic coast of Nova Scotia where eelgrass beds are found. The central emphasis is to predict temperature on scales relevant to coastal ecosystem processes using a high-resolution nearshore oceanographic model based on the Finite Volume Community Ocean Model (FVCOM). The model predictions were evaluated against observed temperature time series at six sites for three years from 2017-2019; the evaluation indicates that the model was able to replicate the temperature variation on time scales from hours to seasonal. We also used various biologically tailored temperature metrics relevant to eelgrass condition, including mean seasonal values and variability, daily ranges, growing degree day (GDD), and warm events, to validate the model against time series observations to better understand the temperature regime at the study sites. Frequency resolved Willmott skill scores were >0.7, and the temperature metrics were well predicted with the exception of a bias in GDD at some of the shallow sites. The eelgrass sites have a wide range of temperature conditions. Mean water temperature in the summer differed by more than 7°C between the shallowest and the deepest sites, and the rate of heat accumulation was fastest at shallow sites which had ≥ 12 extreme warm events per year. While the amplitude of the temperature variations within the high frequency band (<48 hr) was greater in shallower sites, temperature changes on meteorological time scales (48 hr to 60 days) were coherent at all sites, suggesting the importance of coast-wide processes. The results of this study demonstrated that our high resolution numerical model captured biologically relevant temperature dynamics at different time scales and over a large spatial region, and yet still accurately predicted detailed temperature dynamics at specific nearshore sites. Thus, the model can provide important insights into coastal temperature dynamics that are potentially useful for conservation planning and understanding the implications of future change.

Extending trait dispersion across trophic levels: Predator assemblages act as top-down filters on prey communities.

Studies of community assembly typically focus on the effects of abiotic environmental filters and stabilizing competition on functional trait dispersion within single trophic levels. Predation is a well-known driver of community diversity and composition, yet the role of functionally diverse predator communities in filtering prey community traits has received less attention. We examined functionally diverse communities of predators (fishes) and prey (epifaunal crustaceans) in eelgrass (Zostera marina) beds in two northern California estuaries to evaluate the filtering effects of predator traits on community assembly and how filters acting on predators influence their ability to mediate prey community assembly. Fish traits related to bottom orientation were correlated with more clustered epifauna communities, and epifauna were generally overdispersed while fishes were clustered, suggesting prey may be pushed to disparate areas of trait space to avoid capture by benthic sit-and-wait predators. We also found correlations between the trait dispersions of predator and prey communities that strengthened after accounting for the effects of habitat filters on predator dispersion, suggesting that habitat filtering effects on predator species pools may hinder their ability to affect prey community assembly. Our results present compelling observational evidence that specific predator traits have measurable impacts on the community assembly of prey, inviting experimental tests of predator trait means on community assembly and explicit comparisons of how the relative effects of habitat filters and intraguild competition on predators impact their ability to affect prey community assembly. Integrating our understanding of traits at multiple trophic levels can help us better predict the impacts of community composition on food web dynamics as regional species pools shift with climate change and anthropogenic introductions.

Nitrogen Cycling in Widgeongrass and Eelgrass Beds in the Lower Chesapeake Bay

Nitrogen Cycling in Widgeongrass and Eelgrass Beds in the Lower Chesapeake Bay

Promoting effect of Manila clam Ruditapes philippinarum (Adams & Reeve, 1850) on the establishment of eelgrass Zostera marina L. seedlings

It is necessary to restore the declined eelgrass Zostera marina L. beds which have multiple functions. The utilization of seedlings to recover eelgrass beds can maintain the genetic eelgrass diversity; however, the seedling establishment rate that is affected by many habitat factors is very low. Manila clam Ruditapes philippinarum (Adams & Reeve, 1850) transform habitats through several ways. Thus, it is inferred that the clam affects the establishment of eelgrass seedlings in multiple ways, and the seedling establishment rate of eelgrass might not simply increase or decrease under the presence of clams. To verify this hypothesis, a five-month clam-mediated seedling establishment experiment was conducted. The contents of total nitrogen (TN) and exchangeable ammonia NH4-N (Ex-NH) in sediment increased as the clam body size increased, and TN decreased with the increase in clam abundance. There was a positive relationship between the content of organic matter in sediment (OM) and the interaction of body size and abundance of clam. The emergence rate of germinated seeds and the seedling establishment rate increased with increasing clam biomass. They were positively correlated with the interaction of OM and Ex-NH. The seedling establishment rate was negatively correlated with the interaction of water content in sediment (W) and medium diameter of sediment (Ø50), OM and TN. The presence of clams affected the height, chlorophyll b content and superoxide dismutase (SOD) activity of seedlings. The clam body size affected the SOD activity of seedlings by influencing Ex-NH. Thus, the habitat modification of clams with moderate biomass improves the establishment and traits of seedlings in multiple ways. The seedling establishment mediated by Manila clam is useful for eelgrass bed restoration.

Spatial and economic quantification of provisioning service by eelgrass beds in Lake Notoro, Hokkaido, Japan

Eelgrass beds provide a habitat for many high-value fishery resources, and provisioning services, one of the ecosystem services, need to be quantified. However, few examples have been evaluated spatially. We determined the distribution of eelgrass beds in Lake Notoro, a marine lagoon in Hokkaido, Japan, and quantified the provisioning services by the eelgrass beds in relation to Pandalus latirostris, a fishery resource. Acoustic measurement surveys of the eelgrass beds and catch surveys of the shrimp were conducted in July and August 2015. The relationship between catch per unit effort (CPUE) of shrimp and the distribution of eelgrass beds was shown. The estimated distribution area of eelgrass beds was 7.07 km2. Shrimp was frequently caught at water depths of 3–5 m, approximately 200 m from the edge of the eelgrass beds. The expected catch of shrimp in the fishing area of Lake Notoro in 2015 was 25.37 tons and US$ 463.6 thousand. Eelgrass beds were found to affect the fisheries production not only on the inside but also at the edge and outside. The entire coastal space should be evaluated, while considering the effect of the distribution of eelgrass beds, to quantify the provisioning services.

Innovative multi-layered biocement development and marine implementation research that contributes to the creation of resilient eelgrass beds

Eelgrass (Zostera marina) beds are important sites of marine biodiversity. Professor Masataka Kusube, National Institute of Technology, Wakayama College, Japan, has extensive experience in this area of research. He focuses on the development of bio-cements created from locally sourced sea sand and bacteria and collaborates with chemicals and plastics manufacturers and local governments in his research on eelgrass meadows. Hydrogen sulfide interferes with cellular respiration and is therefore toxic to humans and animals. Recent research has suggested toxicity to plants, and it could be linked with a recent widespread decline in eelgrass meadows. Kusube has been developing bio-cements and utilises scanning electron microscopy (SEM) to visually examine its surface structure, as well as using PCR (polymerase chain reaction), 16S multigenomic sequencing, SYBR green staining and cell counts to further investigate and gather data on the growth and germination rates of eelgrass with and without his interventions. In the creation of bio-cements, Kusube and his team used urea-degrading bacteria isolating strains of bacteria that were able to provide the functions required. Using urea-degrading bacteria meant that the researchers could easily isolate them with phenol red staining as these colonies break down urea to produce ammonia, generating a distinct red colouration around colonies when using this indicator. So far, the team has found that water temperature and oxygen concentration can significantly affect germination rates, while Eelgrass growth can be promoted in the presence of organic matter and iron. This suggests the potential to enhance growth by manipulating these elements.

The linkage between spatial and temporal variations in epifaunal and primary producer communities in eelgrass (Zostera marina) beds

Environmental variability within estuaries and lagoons creates environmental gradients. Spatial variations in environments associated with environmental gradients shape spatial variations in primary producer and invertebrate communities. However, whether larger spatial variations are linked to greater temporal variations in the communities remained unclear. To understand the linkage between spatial and temporal variations in the communities and the factors shaping these variations, we targeted various functional groups of primary producers and invertebrates (epifauna) in eelgrass (Zostera marina) ecosystems in lagoons with and without distinct salinity gradients. We tested the following hypotheses: 1) larger spatial variation in the primary producer biomasses and epifaunal community structures (abundance, biomass, and species richness) are associated with greater temporal variation in the structures, and 2) salinity would be a more pronounced factor than water temperature and biomasses of primary producers in shaping the community structures in the lagoon with a salinity gradient. Our results showed that temporal and spatial variations in the primary producer biomasses and community structures of epifauna were larger in the lagoon with a salinity gradient. Moreover, salinity, water temperature, and the biomasses of primary producers affected the spatio-temporal variations in the community structures of epifauna, regardless of the presence of the gradients. We present from these results the connection between spatial and temporal variations of the primary producer and epifaunal community structures and the effects of abiotic and biotic factors shaping the communities.

Distribution pattern and habitat use of the protandrous shrimp Pandalus latirostris in relation to environmental characteristics in Akkeshi waters on the pacific coast of eastern Hokkaido, Japan

A sampling of the protandric shrimp, Pandalus latirostris, was conducted at fixed sites from July 2015 to March 2020 in Akkeshi Bay and the connecting Lake Akkeshi on the Pacific coast of eastern Hokkaido. Based on the occurrence pattern of P. latirostris, most individuals begin mating as males at Age-1, followed by a sex change to females, spawn eggs as females at Age-2, and hatch their eggs in the spring of Age-3. Pre-hatching ovigerous females were mainly found in eelgrass beds near and in Lake Akkeshi, where the water temperature was relatively high. The females probably migrate there to hatch their eggs, making sure of the high survival and growth of the hatched larvae. Juveniles and small males were also abundant in near and in Lake Akkeshi, indicating that many larvae remained in the eelgrass beds where they hatched. These eelgrass beds play an important role in the maintenance of the shrimp population as a major egg-hatching site and nursery habitat in Akkeshi waters. With ontogenetic development, the occurrence rate of P. latirostris gradually increased on the offshore side of Akkeshi Bay, with its body size being larger. As P. latirostris grow, they will probably disperse to the offshore side of Akkeshi Bay. However, the density of P. latirostris in the eelgrass bed in the bay near the lake was extremely high, with its strong preference at all ontogenetic stages. This eelgrass bed would help maintain the shrimp population as a “key habitat” for the shrimp. The site-specific environmental characteristics of vegetation beds influence the distribution and abundance of individuals within a population of P. latirostris through their growth and the associated change in habitat preference. In this study, the importance of maintaining the diverse habitats of P. latirostris will be discussed as part of the shrimp stock management measures.

Low‐Altitude UAV Imaging Accurately Quantifies Eelgrass Wasting Disease From Alaska to California

AbstractDeclines in eelgrass, an important and widespread coastal habitat, are associated with wasting disease in recent outbreaks on the Pacific coast of North America. This study presents a novel method for mapping and predicting wasting disease using Unoccupied Aerial Vehicle (UAV) with low‐altitude autonomous imaging of visible bands. We conducted UAV mapping and sampling in intertidal eelgrass beds across multiple sites in Alaska, British Columbia, and California. We designed and implemented a UAV low‐altitude mapping protocol to detect disease prevalence and validated against in situ results. Our analysis revealed that green leaf area index derived from UAV imagery was a strong and significant (inverse) predictor of spatial distribution and severity of wasting disease measured on the ground, especially for regions with extensive disease infection. This study highlights a novel, efficient, and portable method to investigate seagrass disease at landscape scales across geographic regions and conditions.

Eels as natural samplers highlight spatial heterogeneity in energy flow in an estuary

The high spatiotemporal heterogeneity makes it difficult to ensure the representation of samples in estuarine studies. Using Japanese eels as natural samplers (n = 881), we revealed the spatial heterogeneity of energy flow among three successive estuarine segments (upper, middle, and lower estuaries) of the Hamana Lake−Miyakoda River system on the Pacific side of central Honshu, Japan. In the upper estuary which serves as the nursery ground for eels, the predominant small eels (body weight <30 g) fed mainly on polychaetes (58.8% IRI [index of relative importance]), mainly Hediste atoka. This polychaete species depends on the detritus food chain driven by terrestrial inputs, and the detritus food chain appears to be predominant in the upper estuary. However, large eels (body weight >150 g) fed directly on terrestrial subsidies in the form of fallen insects (49.0% IRI) and earthworms (20.2% IRI), indicating that the detritus food chain does not directly affect the diet of large eels. Terrestrial subsidies in the form of living organisms do not contribute to the diet of eels in the adjacent middle estuary, which is the main growth habitat for eels within an estuary. However, small eels depend on terrestrial subsidies by feeding on oysters (71.6% IRI), which assimilate terrestrial particulate organic matter. The predominant medium eels were highly dependent on the high diversity and biomass of prey groups, as indicated by the high % IRI values of several groups, such as infaunal bivalves (31.7% IRI), oysters (19.0% IRI), amphipods (22.6% IRI), and polychaetes (16.4% IRI). Eelgrass beds usually serve as shelters and foraging areas for medium and large eels in the lower estuary. Despite the high species diversity around seagrass meadows, the eels concentrated on infaunal bivalves (85.4% IRI) with high biomass, predominantly Anadara sp. In addition to being tools for monitoring fauna, eels as natural samplers provide insights into the energy flow in ecosystems.

Distribution of sexually reproductive eelgrass (Zostera marina) seeds in microhabitats of eelgrass beds in intertidal zones

Eelgrass (Zostera marina) seedling establishment based on the sexually reproductive seed bank depends on habitat factors, and there are different microhabitats in eelgrass beds. Seedling abundance varies with microhabitat. Why is the distribution pattern of seedlings so? Is there an edge effect of eelgrass patches on seedling distribution? To clarify the distribution and variation patterns of ungerminated seeds, germinated seeds and seedlings in microhabitats, field investigations were conducted from December 2020 to April 2021. The density of the total seed bank varied with microhabitat except in March. In April, the density of germinated seed banks in the highland, low-lying area edge and low-lying area was 0.00 ± 0.00, 0.33 ± .33 and 7.44 ± 0.96 seeds.cm−3, respectively, and the density in the low-lying area was higher than that in the other microhabitats. The order of density of the seedling bank was highland < low-lying area edge < low-lying area in April. The relative proportion of germinated seeds in the low-lying area was higher than that in the highland from March to April, during which the increase rate in the seedling bank of the highland was lower than that of other microhabitats. The distribution pattern of eelgrass seeds varies with microhabitat. The change characteristics of germinated seeds or seedling banks are related to microhabitats. There are edge effects of eelgrass patches on the distribution of germinated seeds and seedlings. All these factors contribute to the formation of seedling distribution. Sowing eelgrass seeds in the edge area of a continuously distributed eelgrass bed can promote the seedling establishment rate.

Particle-attached Microbes in Eelgrass Vegetation Areas Differ in Community Structure Depending on the Distance from the Eelgrass Bed.

Zostera marina (eelgrass) is a submerged flowering plant often found in the coastal areas of Japan. Large amounts of suspended particles form in highly productive environments, such as eelgrass beds, and the behavior of these particles is expected to affect the surrounding microbial community. We investigated the microbial community structure of suspended particles in three eelgrass fields (Ikuno-Shima Is., Mutsu Bay, and Nanao Bay) and inferred the formation and dynamics of suspended particles from a microbial community structure ana-lysis. Seawater samples were collected directly above each eelgrass bed (eelgrass-covering) and from locations dozens of meters away from the eelgrass bed (bare-ground). In consideration of the two different lifestyles of marine microbes, microbial communities were obtained from particle-attached (PA) and free-living (FL) states. Differences in microbial diversity and community structures were observed between PA and FL in all eelgrass beds. The FL microbial community was similar between the two sampling points (eelgrass-covering and bare-ground), whereas a significant difference was noted in the microbial community structure of suspended particles between the two sampling points. This difference appeared to be due to the supply of organic matter from the eelgrass sea ground and leaf-attached detritus produced by microbial activity. In addition, the classes Flavobacteriia, Alphaproteobacteria, and Gammaproteobacteria were abundant in the PA and FL fractions. Furthermore, many sequences of the key groups (e.g., Planctomycetes and Verrucomicrobia) were exclusively detected in the PA fraction, in which they may circulate nutrients. The present results provide insights into the microbial communities of suspended particles and provide the first step towards understanding their biogeochemical impact on the eelgrass bed.

Fish size spectra from imaging sonar reveal variation in habitat use across nearshore coastal ecosystems

Structured coastal habitats provide foraging opportunities and refuge from predation for fish species of varying size and function. However, comprehensive assessments of fish communities among ecosystems are challenging because of biases arising across traditional sampling methods that target subsets of the community in different habitats (e.g. traps, seines, trawls, or visual census). Here, we used dual-frequency identification sonar (DIDSON) to examine shallow, nearshore habitat use by fishes in multiple structured habitats (seagrass, coral reefs, oyster reefs, rocky reefs, mangroves, woody debris, and docks) relative to soft-sediment habitat across 4 study locations ranging from tropical to temperate: Bocas del Toro, Panama, and Florida, Maryland, and California, USA. We then examined the distribution of individual fish sizes using size-spectra analysis. For temperate docks (Maryland) and eelgrass beds (California), size-spectra slopes were less steep than for soft-sediment habitats, indicating that larger fish associated with these structured habitats. No differences in slopes were identified for (sub)tropical Florida or Panama, although spectra intercepts from docks were higher in each location relative to soft sediment, denoting higher total abundance. Our results suggest geographically stratified habitat use with a tendency towards comparatively greater importance of structure in determining fish size distribution at higher latitudes, and greater importance of structured habitat in governing total abundance at lower latitudes. This study also demonstrates the potential of imaging sonar as a new tool for revealing variation in fish communities among habitats at local to continental scales.

Sea otters in a California estuary: Detecting temporal and spatial dynamics with volunteer monitoring

AbstractVolunteer monitoring can support conservation of imperiled wildlife, by providing higher resolution data in space and time than those available from professional scientists. However, concerns have been raised that data collected by amateurs are inaccurate or inconsistent and thus do not allow for robust detection of spatial or temporal trends. We evaluated the rigor and value of volunteer monitoring data for one iconic wildlife species, the southern sea otter (Enhydra lutris nereis), in Elkhorn Slough estuary in central California, USA, and explored whether volunteer monitoring could provide added value to complement limited professional surveys. First, we compiled and analyzed sea otter counts taken on daily ecotourist boat trips along the estuary, and then compared temporal patterns to data collected by professional scientists tasked with monitoring this federally listed species. Second, we analyzed data on sea otter abundance, habitat use, and behavior collected by a team of trained volunteers, the Elkhorn Slough Reserve Otter Monitoring Program. Overall, we demonstrated the ability to detect important ecological patterns relevant to sea otter conservation and wetland habitat management using volunteer‐derived datasets. Long‐term trends and inter‐annual variability were similar between professional agency monitoring data and volunteer datasets. Moreover, the much higher frequency of volunteer observations allowed for seasonal and tidal dynamics to be detected that could not be revealed by less frequent professional monitoring. We found higher sea otter abundance in the estuary in spring–summer, indicating seasonality in use of the estuary. We detected differences in habitat use of the estuary between higher and lower tides, and greater frequency of foraging at low tide and in certain areas. Volunteer observations revealed fine‐scale differences in habitat use: eelgrass beds were used much more heavily than adjacent areas only a few meters away. Volunteer data can thus provide critical information about coastal habitat use and behavior that can improve conservation strategies for threatened wildlife species.

Protecting our coast for everyone's future: Indigenous and scientific knowledge support marine spatial protections proposed by Central Coast First Nations in Pacific Canada

AbstractWe, the Haíłzaqv, Kitasoo Xai'xais, Nuxalk and Wuikinuxv First Nations, are the traditional stewards of our territories in the Central Coast of British Columbia, Canada. Our traditional laws obligate us to manage and protect our territories for current and future generations. Spatial management is inherent to our cultures through the Hereditary Chief governance system, in which specific people within a lineage inherit the rights and responsibilities for stewarding specific areas.Since the 19th century, we have been experiencing cultural disruptions caused by settler colonialism, which are now worsened by the declines of marine species vital to our cultures. These declines reflect fishery impacts exacerbated by climate change.Western fisheries management focuses on maximum sustained yields (MSY), ignoring body size declines that disrupt food webs and diminish population productivity for vertebrate and invertebrate taxa, thereby eroding resilience to climate change. The worldview encompassed by the MSY framework—take the most that you can without compromising future exploitation while assuming no environmental change—is the antithesis of ours—take only what you need and leave lots for the ecosystem. Furthermore, standard stock assessments do not account for uncertainties inherent to climate change effects on distributions and productivity, and many by‐catch species are unassessed.Consistent with our traditional knowledge, scientific evidence indicates that marine protected areas (MPAs), coupled with other measures to reduce fishing mortality, can restore exploited species, safeguard biodiversity and contribute to fisheries sustainability.In the 2000s, we paired Indigenous knowledge and Western science to develop marine spatial plans. These plans are foundational in our contribution to the ongoing development of the Marine Protected Area Network for Canada's Northern Shelf Bioregion (MPAN‐NSB), for which we are co‐governance partners with 14 other First Nations and the governments of Canada and British Columbia.Our proposed spatial protections for the MPAN‐NSB encompass areas important to many exploited taxa and to corals, sponges, eelgrass beds and other carbon stores. Their implementation would fill conservation gaps which have persisted under current fishery management.Given our history of spatial management through the Hereditary Chief governance system, the MPAN‐NSB is a culturally appropriate way forward for marine conservation in our territories.Read the freePlain Language Summaryfor this article on the Journal blog.

EELGRASS BED MAPPING WITH MULTISPECTRAL UAV IMAGERY IN ATLANTIC CANADA

Abstract. Eelgrass (Zostera marina L.) is a marine angiosperm that grows throughout coastal regions in Atlantic Canada. This study aimed to assess the capability of UAV multispectral imagery to map the presence of eelgrass beds within two estuaries in Atlantic Canada (Souris River and Richibucto River). The images were mosaicked using Agisoft and calibrated in reflectance. The corrected images were classified using a non-parametric supervised classifier (Random Forests). The input features of the classification were the UAV band reflectance and associated bathymetric ratios and vegetation indices. The resulting maps were compared with sonar data. The overall validation accuracy for presence/absence was 91.30% with the Souris image and 86.92%% with the Richibucto images. The limitations of the study are also presented.

Diversity and dynamics of particle-associated and free-living bacteria in eelgrass (Zostera marina) bed along the coast of Japan

As the seagrass leaves remain underwater, the primary source of leaf microbes is considered to be seawater heterotrophic bacterioplankton, which possess the ability to degrade biopolymers and are known to attach to surface and form biofilms. In this study, 16S rRNA gene amplicon sequencing was used to assess bacterial diversity and dynamics of the particle associated (PA) and free-living (FL) fraction of the seagrass-covering seawater (inside) and bulk seawater (outside) among different seagrass bed around Japan. Samples were collected from the three Zostera marinabeds (Ikuno-shima Is., Hiroshima; Nanao Bay, Ishikawa; Mutsu Bay, Aomori Prefecture) around Japan during summer (June-August 2015; July 2016). Prokaryotic DNA was extracted from samples using a FastDNA spin kit according to the manufacturer’s protocol. After extracting DNA, 16S ribosomal RNA (16S rRNA) genes were sequenced by Illumina Miseq platform. The Results showed that PA bacterial communities had a higher (p &lt;0.001) diversity than FL ones. Compared to the outside of the seagrass bed, the inside had lower diversity both in PA and FL fraction. Taxonomic analysis revealed a different community composition between lifestyle (PA vs FL) and sampling point (inside vs outside). Differential abundance analysis showed that PA were significantly enriched in a diversity of Cyanobacteria (Synechococcaceae), Saprospiraceae and Hyphomonadaceae. Conversely, FL were more abundant in Gammaproteobacteria (including Halomonadaceae, Alteromonadaceae), Microbacteriaceae, Campylobacteraceae, Pelagibacteraceae,Acidimicrobiia(OCS155). The present data provide a comprehensive description of the PA and FL microbial community in the seagrass bed and can be useful for better understanding the seagrass microbe interactions.