Geographical distribution of red and green Noctiluca scintillans

The dinoflagellate Noctiluca scintillans is one of the most important and abundant red tide organisms and it is distributed world-wide. It occurs in two forms. Red Noctiluca is heterotrophic and fills the role of one of the microzooplankton grazers in the foodweb. In contrast, green Noctiluca contains a photosynthetic symbiont Pedinomonas noctilucae (a prasinophyte), but it also feeds on other plankton when the food supply is abundant. In this review, we document the global distribution of these two forms and include the first maps of their global distribution. Red Noctiluca occurs widely in the temperate to sub-tropical coastal regions of the world. It occurs over a wide temperature range of about 10°C to 25°C and at higher salinities (generally not in estuaries). It is particularly abundant in high productivity areas such as upwelling or eutrophic areas where diatoms dominate since they are its preferred food source. Green Noctiluca is much more restricted to a temperature range of 25°C–30°C and mainly occurs in tropical waters of Southeast Asia, Bay of Bengal (east coast of India), in the eastern, western and northern Arabian Sea, the Red Sea, and recently it has become very abundant in the Gulf of Oman. Red and green Noctiluca do overlap in their distribution in the eastern, northern and western Arabian Sea with a seasonal shift from green Noctiluca in the cooler winter convective mixing, higher productivity season, to red Noctiluca in the more oligotrophic warmer summer season.

Widespread occurrence of the jellyfish Pelagia noctiluca in Irish coastal and shelf waters

An oceanic cruise (October 2007) revealed the widespread occurrence of Pelagia noctiluca in the NE Atlantic just prior to a major fish kill induced by P. noctiluca in Irish coastal waters.

Mauve Stingers (Pelagia noctiluca) as carriers of the bacterial fish pathogen Tenacibaculum maritimum

Aggregations or blooms of jellyfish are increasingly problematic for the aquaculture industry. Jellyfishassociated mass mortalities of sea-caged fish are most often caused by swarms of oceanic species like Pelagia noctiluca. These relatively large jellyfish get carried by tides and currents onto fish cages, causing them to break up into pathogenic nematocyst-containing pieces that are capable of passing through the mesh of the cages. The main effect on fish is gill damage leading to respiratory distress, but the lesions may also be compounded by bacterial infection, Tenacibaculum maritimum being one of the pathogens involved. In our previous study, we highlighted the ability of the jellyfish Phialella quadrata to carry this important pathogen. However, since these small jellyfish were collected around sea-cages of infected salmon, it was not possible to determine if the jellyfish or the fish themselves were the original source of the bacteria. Results of the current study demonstrate that these filamentous bacteria are present on the mouth of P. noctiluca that had no previous contact with farmed fish. These new results highlight the fact that some Cnidarian species harbour T. maritimum and suggest that jellyfishmight be a natural host for these bacteria whose environmental reservoir has not yet been determined.

High-resolution genetic analysis reveals extensive gene flow within the jellyfish Pelagia noctiluca (Scyphozoa) in the North Atlantic and Mediterranean Sea

Despite the importance of gelatinous zooplankton as components of marine ecosystems, both ecologically and socio-economically, relatively little is known about population persistence or connectivity in jellyfish. In the present study, we employed a combination of nuclear microsatellite markers and sequence data from the mitochondrial cytochrome oxidase I (COI) gene to determine levels and patterns of population genetic structuring in the holoplanktonic jellyfish Pelagia noctiluca across the northeast Atlantic Ocean and Mediterranean Sea. Our results indicate a high degree of connectivity in P. noctiluca, with little evidence of geographical structuring of genetic variation. A small but significant differentiation of Atlantic Ocean and Mediterranean stocks was detected based on the microsatellite data, but no evidence of differentiation was observed with the mtDNA, probably due to the higher power of the microsatellites to detect low levels of genetic structuring. Two clearly distinct groups of genotypes were observed within the mtDNA COI, which probably diverged in the early Pleistocene, but with no evidence of geographical structuring. Palaeodistribution modelling of P. noctiluca at the Last Glacial Maximum (LGM; ca. 21 KYA) indicated large areas of suitable habitat south of the species’ current-day distribution, with little reduction in area. The congruent evidence for minimal genetic differentiation from the nuclear microsatellites and the mtDNA, coupled with the results of the palaeodistribution modelling, supports the idea of long-term population stability and connectivity, thus providing key insights into the population dynamics and demography of this important species

Cloning and characterization of the cDNA for the Brazilian Cratomorphus distinctus larval firefly luciferase: Similarities with European Lampyris noctiluca and Asiatic Pyrocoelia luciferases

Studies on firefly (Lampyridae) luciferases have focused on nearctic species of Photinus and Photuris and Euroasiatic species of Lampyris, Luciola, Hotaria, and Pyrocoelia. Despite accounting for the greatest diversity of fireflies in the world, no molecular studies have been carried out on the highly diverse genera from the neotropical region. Here we report the luciferase cDNA cloning for the larva of the Brazilian firefly Cratomorphus distinctus. The cDNA has 1978 bp and codes for a 547-residue-long polypeptide. Noteworthy, sequence comparison as well as functional properties show the highest degree of similarity with Lampyris noctiluca (93%) and Pyrocoelia spp. (91%) luciferases, suggesting a close phylogenetic relationship despite the geographical distance separating these species. The bioluminescence emission spectrum peaks at 550 nm and, as expected, is sensitive to pH, shifting to 605 nm at pH 6. The kinetic properties of the recombinant luciferase were similar to those of other firefly luciferases. © 2004 Elsevier Inc. All rights reserved.

Noctiluca marina ... /

Also published in Linnés̕ Amoenitates academicae, v. 3, ed. 1, 1756; ed. 2, 1764; ed. 3, 1787, p. 202-210. cf. Hulth, Bibl. Linn. (1907) p. 86.

Feeding Ecology of Humpback Whales in Continental Shelf Waters near Cordell Bank, California

Daytime feeding behavior of humpback whales (Megaptera novaeangliae) in Gulf of the Farallones, California, and adjacent waters was observed during autumn of 1988 to 1990. Bodega Canyon, Cordell Bank, and the Farallon Islands were the primary sites of feeding activity. Fecal samples of whales and zooplankton tows contained euphausiids exclusively, dominated by Thysanoessa spinifera (79%), with lesser amounts of Euphausia pacifica (14%), Nyctiphanes simplex (4%), and Nematoscelis difficilis (3%). In 1988 and 1990, whales also were infrequently observed feeding on small schooling fish, presumably Pacific herring (Clupea pallasii), northern anchovy (Engraulis mordax), and juvenile rockfish (Sebastes spp.). Feeding was the most common behavior observed (52%), and less frequently traveling (23%), milling (21 %), and resting (4%). Whales used different methods to consume euphausiid prey at the surface (0-10 m), in shallow water (11-60 m), and deep water (61-140 m). Humpback whales fed at the surface 56% of time in 1988 and 32% of time in 1990, using primarily lateral lunges to capture swarms of euphausiids. In 1989, no surface feeding was observed; however, deep, long-duration dives were followed by extended surface intervals with many respirations. These 1989 observations coincided with increased prey depth as indicated by depth sounder records of diving whales and prey scattering layers. In 1989, increased prey depth and associated feeding behaviors were strongly associated with unusually high surface temperatures, calm seas, and changes in water circulation. Environmental conditions in 1989 triggered the most intense and wide-spread occurrence of red tide in this region since 1980. Red tide samples collected throughout this period contained Alexandrium (=Gonyaulax) catenella and Noctiluca scintillans. Surface feeding was observed only in 1988 and 1990, when surface prey were available and red tides were very limited in extent, duration, and intensity. Annual variations in humpback whale feeding behavior were related to prey availability which is affected by corresponding environmental conditions. (PDF contains 94 pages)

Los fenómenos de marea roja y toxicidad de moluscos bivalvos en el Mar Argentino

Two unusual blooms of dinoflagellates appeared in the Argentine Continental Shelf in spring/summer period of 1980 and 1981, but these differed, one from the other. The first was an intense red-tide with which were associated no signs of toxicity, whereas the second, although; not showing special coloration, was associated with (and doubtless the cause of) intense toxicity in bivalves of the Gulfs of San Matías and San José and of the shelf waters off Península Valdés; the death of two fishermen was atributed to the latter. The first bloom developed as an unusual surface concentration of the predatory dinoflagellate Noctiluca scintillans. It was supposed that this concentration was produced by a particular combination of processes of circulation of water masses. The second bloom was characterizaed by high concentrations of Gonyalax excavata. Investigations at the time determined that toxins in molluscs of the area correasponded to what is called "paralytic shellfish poison". The bloom of G. excavata was associated with a front between well mixed and well stratified water masses. The maximum toxicity centre occured in the mussel bank "Constanza" (42°23'27"S and 62°45'66"W) which coincides with the front referred to above. (PDF contains 93 pages)

Experiments in gear configuration to reduce bycatch in an estuarine squid-trawl fishery

Three experiments were performed in an estuarine squid-trawl fishery in New South Wales, Australia, to test modifications to trawl nets. Lateral mesh openings were experimentally increased and physical bycatch reduction devices (BRDs) were placed in codends. These modifications aimed to reduce nontargeted catches of fish, while maintaining catches of the targeted broad squid (Photololigo etheridgei) and bottle squid (Loliolus noctiluca). Compared to conventional codends made with 41-mm diamond mesh, codends made with different posterior circumferences and larger 45-mm mesh had no significant effect on the catches of any species. The best performing configurations involved the installation of BRDs designed to separate organisms according to differences in behavior. In particular, versions of a composite square-mesh panel reduced the total weight of bycatch by up to 71% and there was no significant effect on the catches of squid. The results are discussed in terms of the probable differences in behavior between fish and squid in codends. After this study, a square-mesh panel BRD was voluntarily adopted throughout the fishery.

Cloning,Expression and Sequence Analysis of A Luciferase Gene from the Chinese Firefly Pyrocoelia pygidialis

从一种来自中国日行性萤火虫(云南窗萤)发光器官mRNA中克隆、测序并表达了有功能的荧光素酶.云南窗萤荧光素酶的cDNA序列有1647个碱基,编码548个氨基酸残基.从推测得到的氨基酸序列的比对分析得出:云南窗萤的荧光素酶与来自Lampyris noctiluca,L.turkestanicus和Nyctophila cf.caucasica三种萤火虫的荧光素酶有97.8%的序列一致性.从推测得出的氨基酸序列进行系统发育分析,其结果表明:云南窗萤和Lampyris+Nyctophila聚在一起,与同属的发光强夜行性的萤火虫不形成的单系.云南窗萤荧光素酶在大肠杆菌中表达的条带大约70kDa,并且在有荧光素存在时发出黄绿色荧光.对荧光素酶的结构模拟和分析表明,云南窗萤荧光素酶基因的氨基端和羧基端结构域之间的裂沟处存在这5个多肽环,这正是从其他荧光素酶推测得到的催化荧光反应时的底物结合位点.云南窗萤和窗萤属的其他3种萤火虫的荧光素酶卡目比,有13个不同氨基酸位点,位于模拟分子结构的表面.对于这些多肽环、不刚氨基酸残基和晶体结构的进一步研究有利于解释日行和夜行性萤火虫荧光素酶的差异.