Habitats In Coastal Waters Research Articles

Evaluating the efficacy of ecological restoration of fish habitat in coastal waters of Lake Ontario

Ecological restoration is a common strategy applied to degraded wetlands and tributaries in large lakes. As resources are typically limited for restoration, it is essential to ensure that such efforts achieve associated goals. Using both discrete and continuous methods, we evaluated the efficacy of ecological restoration efforts on fish habitat within Canada's largest city, Toronto (Cell 2 and Embayment D of Tommy Thompson Park) relative to a control site (Toronto Islands). First, we used a long-term electrofishing dataset (i.e., discrete) to examine catch and community composition relative to restoration status. Catch for northern pike (Esox lucius) remained constant at both restoration sites, and catch of invasive common carp (Cyprinus carpio) decreased at Embayment D, indicating that exclusion barriers may be effective. Restoration was less effective for largemouth bass (Micropterus nigricans) as catches remained similar after restoration at Cell 2, but decreased within Embayment D. We also found that relative abundance for coldwater species at both restoration sites decreased post-restoration, with increases in warmwater species at Cell 2 and coolwater species at Embayment D. Next, we used a long-term acoustic telemetry dataset (i.e., continuous sampling) with three focal species: largemouth bass, northern pike, and invasive common carp. Based on telemetry, we found that restoration efficacy was species-specific, with largemouth bass present before and after ecological restoration (particularly in spring, which may be associated with spawning), but clear reductions in use of the restored areas for common carp and northern pike. Exclusion barriers, while effective at blocking common carp, appeared to also negatively influence access for northern pike. Using both discrete and continuous methods longitudinally and across both treatment and control sites provided complementary information on the efficacy of restoration works within Toronto Harbour, with electrofishing data highlighting changes in fish community composition while acoustic telemetry provided continuous information on timing and duration of habitat use.

원격탐사자료와 GIS를 활용한 연안해역 잘피 분포 특성

원격탐사자료와 GIS를 활용한 연안해역 잘피 분포 특성

Spatial and temporal diversity of fish captured by light traps in various habitats in coastal waters in the oldest marine protected area in Vietnam and its implications for conservation

Abstract Vietnam's oldest marine protected area, the Con Dao Archipelago, hosts a high diversity of fishes, but they are not taken into account in its management. Knowledge of the spatial and temporal diversity of fishes is critical to identify the ecological functions of protected habitats, including as nurseries and feeding grounds. One way to assess diversity is using light traps that target young fish stages. Fish were collected monthly from June 2016 to May 2017 using light traps in three main habitats: seagrass beds, coral reefs and the harbour. Morphometry and DNA barcoding were used to identify the species caught. A total of 11,293 fish were collected, of which 1,248 were barcoded and assigned to 158 species belonging to 81 genera and 34 families, evidence that coral reefs and seagrass beds in Con Dao marine protected area (MPA) are home to a highly diverse and abundant community of fish species. Species richness and Shannon diversity indices did not differ significantly among sampling sites, but both species composition and diversity indices differed in the wet and dry seasons. The abundance of fish was related to sea water temperatures, which varied significantly depending on the month. During the dry season, fish diversity peaked in April, when the water temperature was highest. Conserving fish in Con Dao MPA is important not only for the characterization of the trophic network in coral reefs and seagrass beds but also for preservation of coral reef ecosystems and endangered species. Ensuring connectivity between coral reefs and seagrass beds in Con Dao MPA would facilitate fish conservation but, at present, the MPA only focuses on protecting fragmented habitats that are home to a number of endangered mammal species. Local authorities should establish a continuum of protected areas along coastal habitats and seasonal controls on fishing as part of sustainable management of MPAs.

Stable isotopes reveal sargassum rafts provide a trophic subsidy to juvenile pelagic fishes

Floating macroalgal rafts can form extensive habitat in coastal waters and support abundant and diverse communities of juvenile fishes. Rafts comprised predominantly of Sargassum spp. are common within the Ningaloo Coast World Heritage Area, Western Australia, and may be an important transitional habitat for pre-settlement coastal fishes. We had three aims: 1) to quantify the diversity and abundance of fishes associated with Sargassum rafts; 2) to use stable isotopes to determine whether fishes associating with rafts preyed on nearby plankton or on prey associated with Sargassum; and 3) to determine whether the food web fishes relied upon was ultimately supported by primary production of Sargassum or planktonic phytoplankton (measured as seston). Fishes and macroinvertebrates associating with Sargassum rafts, zooplankton, and seston were collected at six sites in the Ningaloo Marine Park and analysed for δ15N and δ13C, and the diets of the most common fishes were analysed using MixSIAR. Fishes were more abundant around macroalgal rafts than in open water. Eleven species of juvenile fishes associated with Sargassum rafts, with one species (Histrio histrio (Antennariidae)) represented by juveniles and adults. Four of the five fishes most sampled around Sargassum spp. rafts, (Abudefduf vaigiensis (Pomacentridae), Helotes sexlineatus (Terapontidae), Colurodontis paxmani (Monacanthidae) and Petroscirtes breviceps (Blenniidae)) had generalist diets whose food webs were ultimately supported by greater contributions of primary production from Sargassum spp. (55–72%) than planktonic seston. H. histrio was predominantly piscivorous but still derived most (64%) of its organic matter indirectly from Sargassum spp. Our results reveal the importance of Sargassum rafts as habitat that provides shelter and food for juvenile fishes and adult H. histrio. Moreover, the prevalence of juvenile fishes associating with Sargassum rafts highlights a bidirectional form of benthic-pelagic coupling whereby macroalgae that detach from the benthos provide habitat and a trophic subsidy for pelagic juvenile fishes before they the transition into benthic coastal habitats.

Infection with swim bladder nematode Anguillicola crassus in relation to European eel growth, age, and habitat along the German Baltic coast.

One possible reason for the European eel (Anguilla anguilla) population decline is the neozoan eel swim bladder nematode Anguillicola crassus. To investigate whether the prevalence of A. crassus and the associated swim bladder pathology is related to eel habitat, growth rate, and age, 728 yellow eels from 6 habitats differing in salinity and located along the German Baltic coast were examined between 2005 and 2009. The prevalence of A. crassus varied between habitats, ranging from 9 to 57%. Infection prevalence and the percentage of eels with a damaged swim bladder were significantly higher in inner coastal waters compared to more saline open coastal water. In infected eels, 1 to 32 adult and preadult individuals of A. crassus were observed. The mean infection intensity varied between habitats from 2 to 7 nematodes per eel but did not significantly differ between inner and open coastal waters. Infection prevalence and intensity decreased significantly with age when all open coastal waters and all habitats were combined. Both the lower prevalence of A. crassus and the swim bladder damage of older eels and of eels originating from open coastal water habitats suggest that these eels have a higher fitness for spawning migrations than eels from inner coastal waters. The present study underlines the importance of eel screening on a sufficiently small geographical scale for the accurate estimation of eel recruitment and the identification of priority areas that are likely to produce healthy silver eels.

Anthropogenic impact and antibiotic resistance among the indicator and pathogenic bacteria from several industrial and sewage discharge points along the coast from Pydibhimavaram to Tuni, East Coast of India

Increasing urbanisation and industrialisation of the Visakhapatnam region have brought domestic sewage and industrial wastewater discharge into the coastal ocean. This study examines the indicator and pathogenic bacteria's quantitative abundance and antibiotic susceptibility. This study collected surface and subsurface water samples from ten different regions (147 stations; 294 samples), including 12 industrial discharge points, surrounding stations and two harbours from the coast of Pydibheemavaram to Tuni. Physicochemical parameters like salinity, temperature, fluorescence, pH, total suspended matter, nutrients, chlorophyll-a and dissolved oxygen showed a difference between regions. We noticed the presence of indicator (Escherichia coli and Enterococcus faecalis) and pathogenic (Aeromonas hydrophila, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella and Shigella, Vibrio cholera and Vibrio parahaemolyticus) bacteria among the samples. Waters from the near harbour and Visakhapatnam steel plant showed lower bacterial load with no direct input from industries to the coastal water. Samples collected during the industrial discharge period had a higher bacterial load, including E. coli. Enteric bacteria were found in higher numbers at most stations. Some isolates were resistant to multiple antibiotics with higher antibiotic resistance and multiple antibiotic resistance indexes compared with the other coastal water habitats in the Bay of Bengal. The occurrence of these bacteria above the standard limits and with multiple antibiotic resistance in the study region may pose a potential threat to the local inhabitants. It can create an alarming situation in the coastal waters in the study region.

Long-term Monitoring of Pollution of the Coastal Water Area of Ussuriysk Bay with Metals: Case Study of “Green” Oysters <i>Magallana gigas</i> (<i>= Crassostrea gigas</i>) (Thunberg, 1793)

In September 2021, the content of heavy metals Pb, Cu, Cd, Zn, Ni, Fe, and Mn was estimated in the tissues of the oyster Magallana gigas (= Crassostrea gigas) (Thunberg, 1793) and in the silty fraction of bottom sediments from mollusk habitats in coastal waters around the Muravyov-Amursky Peninsula, including the most polluted area off the western coast of Ussuri Bay of the Sea of Japan. It has been shown that, despite the reclamation of the landfill located here in 2010, being the main source of metal pollution, copper is present in high concentrations in bottom sediments and tissues of oysters, giving them a green color. The mollusks living in this area also retain a high concentration of zinc. The concentrations of Pb, Cd, and Ni in oyster tissues over the past 20 years have decreased by 2–5 times in accordance with the decrease in the number of mobile forms of these metals in bottom sediments; however, they are still 3–6 times higher than regional estimates for polluted water areas. With abnormal accumulation of copper, manganese, on the contrary, demonstrates a decrease in the concentration in the tissues of oysters from the most polluted stations, reflecting the deterioration of the physiological state of mollusks. The results obtained indicate the need to continue the remediation of the western coast of Ussuri Bay and monitor the pollution of coastal waters with metals.

Diversity of echinoderms of class echinoidea and holothuroidea in waingapu old pier, east sumba regency

Echinoderms are in habitats in coastal waters because is a biota that can maintain the sustainability and the balance of the coral reef ecosystem. Human activity in utili zing Echinoderms, namely in Echinoidea and Holothuroidea can affect life his life. The purpose of this study was to determine the diversity of phyla Echinoderms class Echinoidea and Holothuroidea at the Harbor Waingapu Old Pier and its use as a medium Biology learning. The research method used is purposive sampling and analyzed using the approach quantitative descriptive with the Shannon diversity index formula Wiener. Echinoderm samples were calculated using the technique quadratic transects with a plot size of 2 x 2 meters are placed perpendicularly in the direction of 50 meters using a plot of 30 plot. Environmental factors measured are temperature, salinity, degrees acidity (pH) and levels of oxygen (DO). Measurements are taken at each observation station. The results showed 11 species Echinoderms are divided into 2 classes, namely Diadema setosum, Diadema savignyi, Tripneustes gratilla, Strongylocentrotus droebachiensis, Echinocardium flavescens, Clypeaster subdepressus, and Mespilia globulus from the class Echinoidea. Holothuria atra, Holothuria scraba, Euapta godeffroyi and Chiridota rigida from the class Holothuroidea. The diversity index obtained includes medium category with a value of H = 1.696.

Semantic segmentation of seagrass habitat from drone imagery based on deep learning: A comparative study

In this study, the utilization of drone images and deep learning to monitor the seagrass habitat, which is important in the marine ecosystem, is evaluated. Two experiments were conducted to compare the effect of image normalization and the performance of deep learning models in semantic segmentation with drone optical images acquired for the alpine habitats in coastal waters. Z-score and Min-Max normalization techniques were used to examine the effect of image normalization, and U-Net, SegNet, PSPNet, and DeepLab v3+ were used to compare the performance of the deep learning models. As a result, Min-Max normalization demonstrated outstanding performance for optical images, and Z-score normalization for black and white images. Regardless of the normalization of the image, the performance of the models was ranked in the order of U-Net, PSPNet, SegNet, and DeepLab v3+. Although the latest model, DeepLab v3+, was expected to have excellent performance, in fact, U-Net, having a relatively simple structure and a small number of parameters, showed the best performance. As the accuracy of semantic results seems to depend on the deep learning models and normalization methods, an experiment to determine an appropriate normalization method and deep learning model should be preceded for the semantic segmentation of high-resolution optical images in coastal waters.

Dynamics of Stone Habitats in Coastal Waters of the Southwestern Baltic Sea (Hohwacht Bay)

Cobbles and boulders on the seafloor are of high ecological value in their function as habitats for a variety of benthic species, contributing to biodiversity and productivity in marine environments. We investigate the origin, physical shape, and structure of habitat-forming cobbles and boulders and reflect on their dynamics in coastal environments of the southwestern Baltic Sea. Stone habitats are not limited to lag deposits and cannot be sufficiently described as static environments, as different dynamic processes lead to changes within the physical habitat structure and create new habitats in spatially disparate areas. Dynamic processes such as (a) ongoing exposure of cobbles and boulders from glacial till, (b) continuous overturning of cobbles, and (c) the migration of cobbles need to be considered. A distinction between allochthonous and autochthonous habitats is suggested. The genesis of sediment types indicates that stone habitats are restricted to their source (glacial till), but hydrodynamic processes induce a redistribution of individual cobbles, leading to the development of new coastal habitats. Thus, coastal stone habitats need to be regarded as dynamic and are changing on a large bandwidth of timescales. In general, wave-induced processes changing the physical structure of these habitats do not occur separately but rather act simultaneously, leading to a dynamic type of habitat.

Looking Back to Move Forward: Lessons From Three Decades of Research and Management of Cetacean Tourism in New Zealand

Cetacean tourism in Aotearoa New Zealand is now over 30 years old and has experienced substantial growth in visitor numbers and operations. The industry is remarkably diverse, targeting several dolphin and whale species, and encompassing varied habitats in coastal waters, fiords and submarine canyons. The knowledge and experience collected over these past 30 years has both advanced the global understanding of cetacean tourism, and influenced scientific practices for its study and management. Here we review the approaches taken in quantifying the impact of cetacean tourism in New Zealand, and critically assess the efficacy of the research and management strategies adopted. We place particular focus on the Bay of Islands, Hauraki Gulf, Kaikoura, Akaroa and Fiordland, areas that include the oldest, and longest studied industries nationally. We propose a set of best research practices, expose the most notable knowledge gaps and identify emerging research questions. Drawing on perspectives from the natural and social sciences, we outline the key determinants of failure and success in protecting cetacean populations from the detrimental impact of tourism. We suggest four golden rules for future management efforts: (1) acknowledge cetacean tourism as a sub-lethal anthropogenic stressor to be managed with precaution, (2) apply integrated and adaptive site- and species-specific approaches, (3) fully conceptualize tourism within its broader social and ecological contexts, and (4) establish authentic collaborations and engagement with the local community. Lastly, we forecast upcoming challenges and opportunities for research and management of this industry in the context of global climate change. Despite New Zealand's early establishment of precautionary legislation and advanced tourism research and management approaches, we detected flaws in current schemes, and emphasize the need for more adaptive and comprehensive strategies. Cetacean tourism remains an ongoing challenge in New Zealand and globally.

Manajemen Pakan dan Analisis Usaha Budidaya Udang Vaname (Litopanaeus vannamei ) pada Lokasi yang Berbeda di Kabupaten Bangkalan dan Kabupaten Sidoarjo

Asian white shrimp or can be called vannamei shrimp has the Latin name Litopenaeus vannamei has native habitat in coastal waters and American sea waters. This research was carried out in September 2018 in the Asian white shrimp farming business unit Tanjung Putih Village Sepulu District Bangkalan District and in Penatar Sewu Village Tanggulangin District Sidoarjo Regency. This study population used 3 pond plots in Asian white shrimp culture in Tanjung Putih Village, Sepulu District, Bangkalan District and in Penatar Sewu Village Tanggulangin District Sidoarjo Regency. Sample size is determined from the amount of shrimp fry capacity stocked. The sampling technique was carried out by researchers by following activities in the field, census and visiting respondents directly on the farm or in the farmer's group home to obtain the information and data needed. The results showed that the best feed management was obtained the best results on the 4 sample ponds in Sidoarjo with an average final weight growth rate of 9.73 grams at the first partial harvest, 83% Feed Efficiency, and a 90% survival rate. As for the lowest feed management results obtained in sample ponds 1 Bangkalan with a yield of 6.98% growth, feed efficiency by 71% and survival rate of 86%. As for the results of the analysis of vannamei shrimp aquaculture business at different locations in Bangkalan and Sidoarjo districts, it was concluded that the best Production BEP was obtained in Sidoarjo's 4 sample ponds, amounting to 1427 kg. The best R / C ratio and Payback period is the average sample obtained in Sidoarjo. The conclusion of the best feed management and business analysis results is on the sidoajo sample ponds, the sidoarjo sample shows decent and efficient results.

Changes in the summer bird communities with an emphasis on waterfowl on Dolgiy Island during 2004–2017

Waterfowl occupied the prominent rating with respect to abundance among the birds on the Dolgiy Island in the south-eastern part of the Barents Sea in land habitats and coastal water habitats. Comparison of the number of clutches and broods of waterfowl per 10 km of walking trails in different years on the island shows that in recent years (2014, 2016 and 2017), compared to 2004, there was an increase in abundance of the breeding populations of the Barnacle Goose, the White-fronted Goose, the Bean Goose, the Long-tailed Duck and the King Eider. There was a particularly rapid growth in the abundance of the Barnacle Goose for the studied period which, in the land habitats of the island, occupied a leading position in terms of abundance among other geese. An increased abundance of the Barnacle Goose on the island was accompanied by changes in its choice of nesting habitat type and its distribution in the parental care and moulting periods. The results of our study show that with an increase in the nesting density of the Barnacle Goose, the similarity of its nesting habitat types with those of the White-fronted Goose also increased. Some links between the abundance of clutches and broods of waterfowl and weather parameters were observed in different years. The abundance of waterfowl clutches and broods on the island was highest in 2016, which was characterised by the highest average monthly temperature of June and the longest frost-free period for all the years of observation.

Population genetic structure of Etroplus suratensis Bloch, 1790 in South India: preliminary evidence of founder haplotypes shared among populations

Indian estuarine and coastal water habitats have reduced in recent decades because of anthropogenic activities such as coastal development. The pearlspot cichlid Etroplus suratensis is designated as Least Concern, given its wide distribution and presumably large overall population size in South India, despite the declining trend observed in wild populations. To assess the genetic diversity and connectivity among South Indian coastal populations, mitochondrial displacement loop sequence analysis was conducted to provide fundamental information for future conservation studies and an understanding of population dynamics by calculating the haplotype diversity of local populations. The haplotype (h) and nucleotide (π) diversity were very low at most localities, with values ranging from 0.56061 to 0.87879 and from 0.0014 to 0.0046, respectively, which may have resulted from recent population bottlenecks or founder events. The results also revealed a clear genetic differentiation between East and West coast populations, suggesting the existence of a gene flow barrier between them. As the maintenance of genetic connectivity is a prerequisite for local population stability, the preservation of extant habitats and the restoration of water bodies along the coast of India may be the most effective measures for the sustainable maintenance of this species.

Assessment of Coastal Water Habitat with Reference to the Variability of Plankton during Spawning Season of Indian River Shad in Greater Noakhali-Bangladesh

The present study was conducted to quantify the water quality parameters and plankton concentrations of the Meghna river estuary during the spawning season of Hilsa (Tenualosa ilisa) and also to establish knowledge about the habitat. Hilsa (Tenualosa ilisha) is one of the flagship anadromous fish species of Bangladesh that migrate downstream for spawning purposes only through the Ganges-Meghna river system route. The study period constitutes two spawning seasons of Hilsa (Tenualosa ilisha) (June 2014 and February, March 2015). The water quality parameters and plankton concentrations were measured and analyzed by standard methods. A total of 50 genera of plankton identified from the water body belonging to the group Bacillariophyceae, Cyanophyceae, Chlorophyceae, Dinophyceae, Coscinodiscophyceae, Copepoda, Rotifera, Cladoceran, Protozoa, Crustacean larvae and Meroplankton. The phytoplankton density was varied from 2.93×103 to 7.94×103 cells/L and zooplankton density of 1.15×103 cells/L to 1.8×103 cells/L. The plankton concentrations were strongly correlated with the fluctuations of water quality. The water temperature and phytoplankton density was positively correlated (r = 0.75), on the other hand, negative correlation was found between phyplankton and transparency (r = - 0.84). Bacillariophyceae was the most dominant group contributing 78% of phytoplankton and among zooplankton, Copepoda contributes 36%. Shannon-Weiner species diversity index (HE¹) used as an indicator of water quality. It ranged from 2.07 to 2.74 (phytoplankton) and 1.82 to 2.38 (zooplankton). The mean value of phytoplankton was 2.42 ± 0.19 and zooplankton was 2.14 ± 0.16 and it was within the range of 1 to 3, so the water body is moderately polluted. The phytoplankton cell density is a good indicator to determine the trophic status of a particular water body. The mean cell density of phytoplankton was 5372 cells/L and could be classified as oligotrophic. Oligotrophic water body characters lack nutrients which resulted in the lowest density of plankton. Based on plankton density it can be concluded that during spawning season, plankton profile is low which might be hindered Hilsa to migrate this spawning ground.

Quality Index of Subtidal Macroalgae (QISubMac): A suitable tool for ecological quality status assessment under the scope of the European Water Framework Directive

Despite their representativeness and importance in coastal waters, subtidal rocky bottom habitats have been under-studied. This has resulted in a lack of available indicators for subtidal hard substrate communities. However, a few indicators using subtidal macroalgae have been developed in recent years for the purpose of being implemented into the Water Framework Directive (WFD). Accordingly, a quality index of subtidal macroalgae has been defined as a French assessment tool for subtidal rocky bottom habitats in coastal waters. This approach is based on 14 metrics that consider the depth penetration, composition (sensitive, characteristic and opportunistic) and biodiversity of macroalgae assemblages and complies with WFD requirements. Three ecoregions have been defined to fit with the geographical distribution of macroalgae along the French coastline. As a test, QISubMac was used to assess the water quality of 20 water bodies. The results show that QISubMac may discriminate among different quality classes of water bodies.

Morphological and habitat characteristics of settling and newly settled Roughscale Sole Clidoderma asperrimum collected in the coastal waters of northeastern Japan

This report first describes the morphological and habitat characteristics of larval and juvenile Roughscale Sole Clidoderma asperrimum. Five metamorphosing larvae (22.1–31.7 mm standard length, SL) and 12 juveniles (23.7–46.4 mm SL) were collected from two locations in coastal waters of northeastern Japan, Shizugawa Bay (rocky habitats, 6–12 m depth) and Iwaki (sandy habitats, 10–50 m depth), respectively, using a hand net while SCUBA diving and a small trawl net during May–August in 2008 and 2010. Underwater observation in Shizugawa Bay revealed that metamorphosing larvae and juveniles that had settled on rocks or stones showed transparent and variegated body coloration, which is cryptic to a rocky habitat. Juveniles in Iwaki showed monotonic coloration. The settlement would occur during metamorphosis because the same larva observed on a stone subsequently swam with a left-lateralized body posture. The larval morphology was characterized by a dense covering of fine spines on the whole body surface. Spines on the ocular side developed steadily, gradually forming bony tubercles with growth, whereas those on the blind side regressed with development and finally disappeared in metamorphosed juveniles. Our results indicate that Roughscale Sole can settle and adapt to rocky and sandy habitats in coastal waters with wide depth range.

BACTERIA ISOLATED FROM DUGONGS (DUGONG DUGON) SUB-MITTED FOR POSTMORTEM EXAMINATION IN QUEENSLAND, AUSTRALIA, 2000–2011

Microbial infection may contribute to disease in a significant proportion of marine mammal mortalities, but little is known about infectious bacterial species and their prevalence in dugongs (Dugong dugon). This study represents a survey of the species of bacteria and fungi isolated from dugongs submitted to the University of Queensland's School of Veterinary Science for postmortem examination. Thirty-six dugongs were included in the survey, with 23 species of bacteria and four species of fungus cultured from lesions that were suspected of contributing to local infection, systemic infection, or both. The most abundant bacteria included Aeromonas spp., Clostridium spp., Vibrio spp., Enterococcus faecalis, and Pseudomonas spp. In six cases, the microorganism(s) cultured were considered to have been associated with disease. Mixed infections containing Aeromonas spp. and Vibrio spp.; Morganella morganii, Pasteurella multocida, and Serratia marcescens; and Actinomyces spp. and Peptostreptococcus spp. were associated with pneumonia or pleuritis, and Enterococcus faecalis was associated with a multisystemic infection in a neonate. Clostridium spp. was cultured from two animals with peritonitis and likely septicemia. The significance of many of the other isolates is uncertain because the samples were taken after death, and some of the species isolated may represent postmortem overgrowth. It is also difficult to fulfil Koch's postulates through experimental infection in marine mammals. Regardless, this information will assist clinicians working with dugongs to make treatment decisions and the baseline data on the prevalence of bacterial and fungal species is of value for monitoring coastal water habitat health and risks of zoonotic disease transmission.

Alternative spatially enhanced integrative techniques for mapping seagrass in Florida's marine ecosystem

Seagrass is an important component of coastal marine ecosystems. Seagrass mapping provides a means for assessing seagrass health by monitoring the spatial distribution and density of seagrass habitat in coastal waters. Recent image processing and satellite technologies present the opportunity to leverage quantitative techniques that have the potential to improve upon traditional photo-interpretation techniques in terms of cost, mapping fidelity, and objectivity. Integrated spatial and spectral processing techniques were identified as an alternative method for mapping seagrass extent and density from an IKONOS satellite image of Springs Coast, Florida. These spatially enhanced integrative mapping techniques objectively standardize seagrass-monitoring efforts and enhance mapping capabilities by characterizing spatial seagrass density gradients. A combination of water column correction, pixel classification, and image segmentation techniques provided a seagrass density index map that represented seagrass density and distribution with high spatial detail and overall accuracy (77%) comparable to photo-interpretation techniques. Satellite imagery-based spatially enhanced image processing techniques were found to provide a consistent, quantitative, and cost-effective alternative for seagrass mapping in Springs Coast with the potential to be transferred to other parts of the world. A cost savings analysis concluded that there was a 13% cost saving using satellite photo-interpretation and a 47% cost saving using enhanced satellite classification when compared to aerial photo-interpretation.

Green sturgeon distribution in the Pacific Ocean estimated from modeled oceanographic features and migration behavior.

The green sturgeon (Acipenser medirostris), which is found in the eastern Pacific Ocean from Baja California to the Bering Sea, tends to be highly migratory, moving long distances among estuaries, spawning rivers, and distant coastal regions. Factors that determine the oceanic distribution of green sturgeon are unclear, but broad-scale physical conditions interacting with migration behavior may play an important role. We estimated the distribution of green sturgeon by modeling species-environment relationships using oceanographic and migration behavior covariates with maximum entropy modeling (MaxEnt) of species geographic distributions. The primary concentration of green sturgeon was estimated from approximately 41–51.5° N latitude in the coastal waters of Washington, Oregon, and Vancouver Island and in the vicinity of San Francisco and Monterey Bays from 36–37° N latitude. Unsuitably cold water temperatures in the far north and energetic efficiencies associated with prevailing water currents may provide the best explanation for the range-wide marine distribution of green sturgeon. Independent trawl records, fisheries observer records, and tagging studies corroborated our findings. However, our model also delineated patchily distributed habitat south of Monterey Bay, though there are few records of green sturgeon from this region. Green sturgeon are likely influenced by countervailing pressures governing their dispersal. They are behaviorally directed to revisit natal freshwater spawning rivers and persistent overwintering grounds in coastal marine habitats, yet they are likely physiologically bounded by abiotic and biotic environmental features. Impacts of human activities on green sturgeon or their habitat in coastal waters, such as bottom-disturbing trawl fisheries, may be minimized through marine spatial planning that makes use of high-quality species distribution information.