106 research outputs found
Pollution can drive marine diseases
No full textHumans pollute the marine environment biologically, chemically, and physically, which can potentially drive or facilitate the emergence, proliferation, or impact of disease. This chapter synthesizes what is known about the effects of biological (e.g., wastewater), chemical (e.g., pharmaceuticals), and physical (e.g., sound/light) pollution on marine disease dynamics. The presence of these pollutants has been found to alter disease prevalence, increase host susceptibility to infection, and alter the spread and host range of different diseases. Despite the importance of the marine environment as a primary food source for humans, many complexities linking disease ecology and pollution are yet to be explored. Future investigation of these connections would benefit from an integrated approach using experimental, environmental, molecular, and pathological methods
The Ecological Ramifications of Disease and Density in the Caribbean Spiny Lobster, \u3ci\u3ePanulirus argus\u3c/i\u3e
No full textIn 1999, I discovered the first virus known to be pathogenic to any species of lobster. HLV-PA is a pathogenic herpes-like virus that infects juvenile Caribbean spiny lobster, Panulirus argus, in the waters off south Florida (USA), and it alters the behavior and ecology of this species in fundamental ways. Gross signs of HLV-PA infection are lethargy, morbidity, cessation of molting, and discolored, “milky” hemolymph that does not clot. HLV-PA infects the hemocytes of host lobsters, specifically the hyalinocytes and semi-granulocytes, but not the granulocytes. When hemolymph from infected donors was injected into healthy juvenile lobsters, 90% of the healthy individuals became infected within 80 days. In another set of laboratory trials, 40% of the juvenile lobsters that ingested conspecific tissue infected with HLV-PA developed the disease, and in a third experiment wherein transmission by contact or waterborne means was tested, 63% of the lobsters(CL), 33% of lobsters 30–40 mm CL and 10% of lobsters 40–50 mm CL became infected within 80 days.
In field surveys from 2000–2001, up to 40% of the juveniles at each of twelve sites (mean = 8%) had the disease. The disease was most prevalent (mean = 16%) among the smallest juveniles (i.e.,CL) and, thus far, appears limited to juveniles. However, all of the surveys of disease prevalence are based on gross, visual signs of late stages of infection, and are, therefore, conservative estimates. A diagnostic tool to assess infection at earlier stages has not yet been developed.
Field observations and laboratory experiments indicate that healthy juvenile lobsters avoid diseased conspecifics, which is only the second report of such behavior in any animal. The prevalence of the disease in wild lobster populations is not correlated with population density, even when lobsters were experimentally concentrated at sites with artificial shelters. Moreover, enhanced density does not appear to have a detrimental effect on population dynamics such as nutritional condition and short-term residency, likely due to their normal gregariousness. Thus, juvenile spiny lobsters appear to have developed remarkable contradictory behaviors, avoidance of infected conspecifics and gregariousness, both of which may ultimately enhance survival of uninfected lobsters
Small-scale spatial variation in population- and individual-level reproductive parameters of the blue-legged hermit crab Clibanarius tricolor
No full textManagement of the few regulated ornamental fisheries relies on inadequate information about the life history of the target species. Herein, we investigated the reproductive biology of the most heavily traded marine invertebrate in the western Atlantic; the blue-legged hermit crab Clibanarius tricolor. We report on density, individual-level, and population-level reproductive parameters in 14 populations spanning the Florida Keys. In C. tricolor, abundance, population-level, and individual-level reproductive parameters exhibited substantial small-scale spatial variation in the Florida Keys. For instance, the proportion of brooding females varied between 10–94% across localities. In females, average (±SD) fecundity varied between 184 (±54) and 614 (±301) embryos crab-1 across populations. Fecundity usually increases with female body size in hermit crabs. However, we found no effect of female body size on fecundity in three of the populations. Altogether, our observations suggest that C. tricolor may fit a source-sink metapopulation dynamic in the Florida Keys with low reproductive intensity and absence of a parental body size—fecundity relationship resulting in net reproductive loses at some localities. We argue in favor of additional studies describing population dynamics and other aspects of the natural history of C. tricolor (e.g., development type, larval duration) to reveal ‘source’ populations, capable of exporting larvae to nearby populations. Our observations imply that future studies aimed at assessing standing stocks or describing other aspects of the life history of this hermit crab need to focus on multiple localities simultaneously. This and future studies on the reproductive biology of this species will form the baseline for models aimed at assessing the stock condition and sustainability of this heavily harvested crustacean
Small-scale spatial variation in population- and individual-level reproductive parameters of the blue-legged hermit crab<i>Clibanarius tricolor</i>
No full textManagement of the few regulated ornamental fisheries relies on inadequate information about the life history of the target species. Herein, we investigated the reproductive biology of the most heavily traded marine invertebrate in the western Atlantic; the blue-legged hermit crabClibanarius tricolor. We report on density, individual-level, and population-level reproductive parameters in 14 populations spanning the Florida Keys. In C. tricolor, abundance, population-level, and individual-level reproductive parameters exhibited substantial small-scale spatial variation in the Florida Keys. For instance, the proportion of brooding females varied between 10–94% across localities. In females, average (±SD) fecundity varied between 184 (±54) and 614 (±301) embryos crab-1 across populations. Fecundity usually increases with female body size in hermit crabs. However, we found no effect of female body size on fecundity in three of the populations. Altogether, our observations suggest that C. tricolor may fit a source-sink metapopulation dynamic in the Florida Keys with low reproductive intensity and absence of a parental body size—fecundity relationship resulting in net reproductive loses at some localities. We argue in favor of additional studies describing population dynamics and other aspects of the natural history of C. tricolor (e.g., development type, larval duration) to reveal ‘source’ populations, capable of exporting larvae to nearby populations. Our observations imply that future studies aimed at assessing standing stocks or describing other aspects of the life history of this hermit crab need to focus on multiple localities simultaneously. This and future studies on the reproductive biology of this species will form the baseline for models aimed at assessing the stock condition and sustainability of this heavily harvested crustacean.</jats:p
Challenges for scanning electron microscopy and inspection on the nanometer scale for non-IC application: and how to tackle them using computational techniques
No full textIn this paper key challenges posed on metrology by feature dimensions of 20nm and below are discussed. In detail, the need for software-based tools for SEM image acquisition and image analysis in environments where CD-SEMs are not available and/or not flexible enough to cover all inspection tasks is outlined. These environments include research at universities as well as industrial R and D environments focused on non-IC applications. The benefits of combining automated image acquisition and analysis with computational techniques to simulate image generation in a conventional analytical SEM with respect to the overall reliability, precision and speed of inspection will be demonstrated using real-life inspection tasks as demonstrators.ImPhys/Charged Particle Optic
Parasite avoidance behaviours in aquatic environments
No full textParasites, including macroparasites, protists, fungi, bacteria and viruses, can impose a heavy burden upon host animals. However, hosts are not without defences. One aspect of host defence, behavioural avoidance, has been studied in the terrestrial realm for over 50 years, but was first reported from the aquatic environment approximately 20 years ago. Evidence has mounted on the importance of parasite avoidance behaviours and it is increasingly apparent that there are core similarities in the function and benefit of this defence mechanism between terrestrial and aquatic systems. However, there are also stark differences driven by the unique biotic and abiotic characteristics of terrestrial and aquatic (marine and freshwater) environments. Here, we review avoidance behaviours in a comparative framework and highlight the characteristics of each environment that drive differences in the suite of mechanisms and cues that animals use to avoid parasites. We then explore trade-offs, potential negative effects of avoidance behaviour and the influence of human activities on avoidance behaviours. We conclude that avoidance behaviours are understudied in aquatic environments but can have significant implications for disease ecology and epidemiology, especially considering the accelerating emergence and re-emergence of parasites.peerReviewe
Cirolana westbyi, (Isopoda: Cirolanidae) a new species in the ‘Cirolana parva-group’ from the Turneffe Atoll, Belize
No full textCirolana westbyi n. sp., a novel species in the ‘Cirolana parva-group’is described from the Turneffe Atoll, Belize using an integratedmolecular and morphological approach. The 18S ribosomal RNAgene for C. westbyi n. sp. and also for Cirolana parva Hansen, 1890are provided, in addition to new primers, developed for theCirolanidae 18S gene.The key morphological character for separating C. westbyi n. sp.from other Cirolana is the shape of the uropodal rami: the uropodalendopod is convex on the lateral side while the mesial side is straight.Comparison of the 18S gene shows that C. parva is 95.96% identicalto C. westbyi n. sp. across 68% coverage, but due to two uniqueinsertions (‘INS-1’ and ‘INS-2’) into the 18S gene of C westbyi n. sp.,which may function as loop regions, they appear to be geneticallydistinct and different species. This is also supported by phylogeneticanalysis, which also highlights some potential paraphyly betweenthe three families, Cirolanidae, Aegidae and Corallanidae.Our morphological description of a new species of cirolanidalong with a phylogenetic support using 18S sequence data forspecies within and around the Cirolanidae, provides greater contextfor the ‘Cirolana parva-group’
Effect of simulated catch-and-release angling on postrelease mortality and egg viability in sockeye salmon (Oncorhynchus nerka)
No full textCatch-and-release angling of salmonids is a widely implemented fisheries management strategy intended to provide recreational fishing opportunities while limiting harvest. Previous research has indicated mortality may be low, but the extent of sublethal impacts, including inability to reach spawning grounds or decreased spawning effectiveness, is relatively under-studied. Sockeye salmon (Oncorhynchus nerka) were subjected to simulated catch-and-release events, with a subset also enduring air exposure, to determine how physiological stress influences the ability of sockeye salmon to reach spawning grounds and the viability of eggs produced. Short-term postrelease mortality was highest for fish that were subjected to air exposure, but once recovered, neither simulated catch-and-release nor air exposure had a major impact on their ability to reach spawning grounds. Egg viability was similar between treatment groups, indicating physiological stress associated with the trials did not have a negative impact on reproduction. These results suggest that handling, especially air exposure, is the primary concern and substantially impacts the short-term postrelease mortality of sockeye salmon, which has important implications for management.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Integrative taxonomy of the ornamental ‘peppermint’ shrimp public market and population genetics of Lysmata boggessi, the most heavily traded species worldwide
No full textThe ornamental trade is a worldwide industry worth >15 billion USD with a problem of rampant product misidentification. Minimizing misidentification is critical in the face of overexploitation of species in the trade. We surveyed the peppermint shrimp ornamental marketplace in the southeastern USA, the most intense market for peppermint shrimps worldwide, to characterize the composition of species in the trade, reveal the extent of misidentification, and describe the population genetics of the true target species. Shrimps were bought from aquarium shops in FL, GA, SC, and NC. We demonstrated, contrary to popular belief (information from dealers), that the most heavily traded species in the market was Lysmata boggessi, an endemic species to the eastern Gulf of Mexico, and not Lysmata wurdemanni. Importantly, only when color pattern or genetic markers in conjunction with morphological traits were employed, was it was possible to unequivocally identify L. boggessi as the only species in the trade. The intensity of the market for peppermint shrimps in the USA has led to L. boggessi being the most traded species worldwide. Misidentification in the shrimp aquarium trade is accidental and involuntary, and is explained by remarkable similarity among congeneric species. Using sequences of the 16S-mt-DNA marker, we found no indication of population genetic structure in the endemic L. boggessi across 550 km of linear coast. Therefore, this species can be considered genetically homogeneous and a single fished stock. Still, we argue in favor of additional studies using more powerful markers (e.g., SNPs) capable of revealing genetic structure at a finer spatial-scale. Our results will help advance management and conservation policies in this lucrative yet understudied fishery. Future studies of other ornamental fisheries will benefit from using an integrative taxonomic approach, as we demonstrate here
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