Oyster Mortality Studies in Virginia: Ill. Epizootiology of a Disease Caused by Haplosporidium costale Wood and Andrews

A short, sharp eplzootic disease of oysters on Seaside of Eastern Shore, Virginia, has been associated with a new pathogen, Haplosporidium costale Wood and Andrews. Native oysters in trays have shown closely timed May-June losses for three consecutive years. Losses at other seasons were small. May-June losses ranged from 12 to 14 percent in 1959 to 36 to 44 percent in 1960. James River oysters moved to Seaside showed higher losses than natives after a year of acclimation. Oysters in Bayside creeks revealed late summer losses caused by Dermocystidimn marinmn Mackin, Owens, and Collier rather than May-June deaths. The new pathogen was found in live oysters from March to July, and in a high proportion of gapers in May and June. The epizootiology is well established for these periods but unknown for the rest of the year. Increasing prevalence of another pathogen ( MSX ), causing Delaware Bay disease, has complicated mortality studies. Losses are most serious in older oysters which have been held beyond the usual period of culture. Careful timing of planting and early harvesting permit oystermen to a void serious losses

Effects of Slotted Water Control Structures on Nekton Movement within Salt Marshes

Water control structures (WCSs) restrict hydrological connectivity in salt marshes and thereby impede nekton movement within the greater habitat mosaic. Transient fishery species, which spawn outside salt marshes and must get past these barriers to reach spawning areas or salt-marsh nurseries, are especially vulnerable to these structures. Water control structures incorporating slots (narrow vertical openings spanning most of the water column) are thought to improve nekton passage; however, few studies have directly examined nekton passage through WCS slots. Dual-frequency identification sonar (DIDSON) acoustic imaging was used monthly (April-September 2010) on diurnal flood tides to examine nekton movement through 15-cm-wide slots at two identical WCSs located in Louisiana tidal marsh channels. Nekton behavior was compared between these WCSs and a nearby natural salt-marsh creek. Examination of 12 h of subsampled acoustic data revealed large concentrations of salt-marsh nekton at the WCSs (n = 2,970 individuals total), but passage rates through the slots were low (\u3c= 10% of total observed individuals migrated via the slots). Most migrating fish were observed leaving the managed area and swimming against a flood tide. The mean size of migrating individuals (similar to 25 cm TL) did not differ in relation to swimming direction (going into versus exiting the managed marsh) and was similar to that reported from other studies examining similar slot widths. Nekton formed congregations in the WCS channel, but no congregations were observed in the natural salt-marsh creek, even though nekton species composition and sizes were similar among sites. The WCSs in our study appear to function as ecological hot spots, where large individuals may encounter enhanced foraging opportunities but also fishing mortality and where smaller individuals may experience greater predation rates

Brain architecture in the terrestrial hermit crab Coenobita clypeatus (Anomura, Coenobitidae), a crustacean with a good aerial sense of smell

<p>Abstract</p> <p>Background</p> <p>During the evolutionary radiation of Crustacea, several lineages in this taxon convergently succeeded in meeting the physiological challenges connected to establishing a fully terrestrial life style. These physiological adaptations include the need for sensory organs of terrestrial species to function in air rather than in water. Previous behavioral and neuroethological studies have provided solid evidence that the land hermit crabs (Coenobitidae, Anomura) are a group of crustaceans that have evolved a good sense of aerial olfaction during the conquest of land. We wanted to study the central olfactory processing areas in the brains of these organisms and to that end analyzed the brain of <it>Coenobita clypeatus </it>(Herbst, 1791; Anomura, Coenobitidae), a fully terrestrial tropical hermit crab, by immunohistochemistry against synaptic proteins, serotonin, FMRFamide-related peptides, and glutamine synthetase.</p> <p>Results</p> <p>The primary olfactory centers in this species dominate the brain and are composed of many elongate olfactory glomeruli. The secondary olfactory centers that receive an input from olfactory projection neurons are almost equally large as the olfactory lobes and are organized into parallel neuropil lamellae. The architecture of the optic neuropils and those areas associated with antenna two suggest that <it>C. clypeatus </it>has visual and mechanosensory skills that are comparable to those of marine Crustacea.</p> <p>Conclusion</p> <p>In parallel to previous behavioral findings of a good sense of aerial olfaction in C. clypeatus, our results indicate that in fact their central olfactory pathway is most prominent, indicating that olfaction is a major sensory modality that these brains process. Interestingly, the secondary olfactory neuropils of insects, the mushroom bodies, also display a layered structure (vertical and medial lobes), superficially similar to the lamellae in the secondary olfactory centers of <it>C. clypeatus</it>. More detailed analyses with additional markers will be necessary to explore the question if these similarities have evolved convergently with the establishment of superb aerial olfactory abilities or if this design goes back to a shared principle in the common ancestor of Crustacea and Hexapoda.</p

Fish remains, mostly otoliths, from the non-marine early Miocene of Otago, New Zealand

Fish remains described from the early Miocene lacustrine Bannockburn Formation of Central Otago, New Zealand, consist of several thousand otoliths and one skeleton plus another disintegrated skull. One species, Mataichthys bictenatus Schwarzhans, Scofield, Tennyson, and T. Worthy gen. et sp. nov., an eleotrid, is established on a skeleton with otoliths in situ. The soft embedding rock and delicate, three−dimensionally preserved fish bones were studied by CT−scanning technology rather than physical preparation, except where needed to extract the otolith. Fourteen species of fishes are described, 12 new to science and two in open nomenclature, representing the families Galaxiidae (Galaxias angustiventris, G. bobmcdowalli, G. brevicauda, G. papilionis, G. parvirostris, G. tabidus), Retropinnidae (Prototroctes modestus, P. vertex), and Eleotridae (Mataichthys bictenatus, M. procerus, M. rhinoceros, M. taurinus). These findings prove that most of the current endemic New Zealand/southern Australia freshwater fish fauna was firmly established in New Zealand as early as 19–16 Ma ago. Most fish species indicate the presence of large fishes, in some cases larger than Recent species of related taxa, for instance in the eleotrid genus Mataichthys when compared to the extant Gobiomorphus. The finding of a few otoliths from marine fishes corroborates the age determination of the Bannockburn Formation as the Altonian stage of the New Zealand marine Tertiary stratigraphy.Werner Schwarzhans, R. Paul Scofield, Alan J.D. Tennyson, Jennifer P. Worthy, and Trevor H. Worth

Marine Fish Faunal Survey

Project No: M-R-3; Date: June 29, 1959; Period Covered: August, 1958 - March, 1959Objectives: To determine the distribution of fish species, particularlythose in little sampled habitats, and gain any life history data possible.Procedure: Collections of fishes from the Texas jetties and oysterreefs by the use of rotenone

Ecological Survey of the Lower Galveston Bay Area

Project No: M-3-R-1; Date: August 26, 1959; Period Covered: September 1, 1958 - August1, 1959; Job No: F-3Ecological Studies Related to PollutionObjectives: Study of areas of physical pollutants and the related fauna to determine effects of pollutants on populations in the area.

Basic Ecological Survey of Area M-3

Project No: M-3-B-1; Date: September 1, 1959; Period Covered; September 1, 1958 - September 1, 1959; Job No: A-3A Checklist of Fishes of Area M-3Objectives: To determine forms present, their relative abundance and life histories and relationships to hydrography.Procedure: Stations were occupied in Area M-3 and collections were made monthly with seines, nets, trawls, etc. Associated data on hydrography and other data were taken. Other data were taken