Evaluation Of In-Situ Silhouette Photography In Investigations Of Estuarine Zooplankton And Ichthyoplankton

Trials of a paired-net towing frame fitted with a submersible 35-mm camera system were conducted in Chesapeake Bay in 1989-1990 to 1) demonstrate the use and efficiency of in situ silhouette photography in studies of estuarine zooplankton and ichthyoplankton; 2) determine the taxonomic potential of in situ silhouette photography in several estuarine habitats; and 3) compare estimates of plankton density from in situ silhouette photographs with concurrent preserved net collections. Time required to split, sort and enumerate plankton in preserved samples was 2-75 h per sample longer than the time required to view and enumerate silhouettes on film. Ninety-four taxa (or different ontogenetic stages of the same taxon) were identified on film. Of these, 55% were classified to genus or species. The camera-net system failed to detect 16 of 31 rare or uncommon categories of zooplankton at one or more stations. Abundance estimates of two gelatinous forms (ctenophores and doliolids) were provided by the camera but these taxa could not be counted or were absent in paired, preserved collections. There were no detectable differences in estimates of abundance provided by the camera and the paired, preserved collection for hydromedusae, polychaete larvae, marine and some freshwater Cladocera, cyprid stages of barnacles, larval stomatopods, caridean and some brachyuran zoeae, megalopae, and fish eggs. Differences in plankton density estimated by the camera and the paired net were significant for some freshwater cladocera, gastropod larvae, some brachyuran zoeae, mysids, and chaetognaths. Statistical results were mixed, depending upon locality, for copepods, naupliar stages of barnacles, and fish larvae. For all categories of planktonic taxa that differed significantly from net collections, in situ photography provided lower density estimates than the net. Underestimation was partly attributed to the poor photographic qualities of some taxa and stalling of plankton along the sides of the camera net

Systematics Of The Pearlfishes (Pisces, Carapidae)

A review of taxonomy, anatomy, ontogeny, ecology, and phylogeny of the ophidiiform family Carapidae was conducted using over 2,300 larval, juvenile and adult specimens. A cladistic classification based on swimbladder morphology, developmental and osteological characters of the vertebral column, fins, pectoral and pelvic girdles, gill arches, ethmoid, jaws, and habitat is presented. A total of 31 species (6 new names and one unnamed larval form) in seven genera are recognized in two subfamilies. A species previously assigned to Echiodon is made the type of a new monotypic genus. Species of the tribe Carapini are rearranged in the genera Carapus and Encheliophis largely on the basis of swimbladder morphology. Larvae are described for all genera except Encheliophis whose larvae are predicted to resemble those of Carapus. The vexillifer larva is unique to carapids. The tenuis juvenile stage, however, may be restricted to the ecologically specialized genera, especially Carapus and Encheliophis. The family is distributed over broad depth (0-2,000 m) and latitudinal (ca. 65-degrees-N to 60-degrees-S) ranges. In general taxa with more plesiomorphic characters are found in deeper water and higher latitudes while taxa with more apomorphic characters are found in tropical, shallow water. Highly specialized inquiline behavior is found in both tribes of the Carapinae and our phylogenetic hypothesis specifies independent acquisition of molluscan inquilinism, at least. Within the Carapini the genus with the most apomorphic characters, Encheliophis, is the most successful holothurian inquiline and the only holothurian inquiline in the Indo-Pacific. Species in its sister genus, Carapus, switch to non-holothurian primary hosts (asteroids or ascidians) when sympatric with Encheliophis in the Indo-Pacific. Atlantic species of Carapus retain holothurians as primary hosts. The distribution of sister species is usually allopatric and suggests that the presence or absence of inquiline behavior has no bearing on mode of speciation. Vicariance of sister species is frequently along depth or latitudinal gradients. There are no amphi-American sister species; the sister group of all eastern Pacific species or populations of carapids is either another Pacific form or an Atlantic-Pacific clade

Description And Occurrence Of Vexillifer Larvae Of Echiodon (Pisces, Carapidae) In The Western North-Atlantic And Notes On Other Carapid Vexillifers

Five hundred twenty-two vexillifers of an unnamed species of the carapid genus Echiodon are reported from ichthyoplankton collections made in the Caribbean Sea, Gulf of Mexico, Middle Atlantic Bight, Sargasso Sea, and Scotian Shelf. These are compared with 36 vexi1lifers and one juvenile of the only other known western Atlantic carapine, Campus ber- I/ludensis, as well as two small unidentified western Atlantic vexillifers, and eight eastern Pacific vexillifers of E. exsiliul/l. Vexillum placement relative to anal-fin origin, myomeres, and vertebral centra appears to be a useful character for separating Echiodon vexillifers from other western Atlantic carapids. The vexillum in Echiodon is posteriad of a vertical through the anal-fin origin, over myomeres 9 to 12 and centra 10 or II. The vex ilium of Echiodoll sp. was examined in detail and is bilateral, each component of which consists of a distal and proximal element. The paired proximal elements rest on a distal cartilaginous radial which is supported by a slipper-shaped, compound cartilaginous proximal radial (pterygiophore) in Echiodoll sp. and by a rod-shaped, simple proximal radial in C. bl\u27Ymudellsis. The structure is covered by a fleshy sheath which is highly ornamented in C. bermudellsis but less so in Echiodoll sp. The presumed origin of percoid predorsal bones from an ancestor with vexillar supporting structures is questioned. Most available vexillifers of Echiodoll sp. were captured in the eastern Gulf of Mexico. Additional larger size classes were taken from off Bermuda and north of Cape Hatteras to the Scotian Shelf. These and several other subtropical teleost larvae appear to be regularly dispersed northward by the Gulf Stream

Nearshore ichthyoplankton associated with seagrass beds in the lower Chesapeake Bay

Estuaries serve as important nursery habitats for larvae and juveniles of many species of fishes and invertebrates. Within the estuary, however, partitioning may occur among main channel. mud flat, tidal creek, and vegetated habitats. In this study we describe the egg, larval, and juvenile fish assemblages in shallow areas of submerged aquatic vegetation (SAV) of the lower Chesapeake Bay and compare them with those over the adjacent, shallow sand habitat. Densities at night over all habitats were about 1 order of magnitude higher than daytime densities, and were highest in summer. The SAV habitats were not important spawning sites for species with pelagic eggs, but were important for species brooding eggs or with demersal eggs. Overall, collections were dominated by the bay anchovy Anchoa mitchilli, , but contained many species not commonly found in the midchannel ichthyoplankton described in earlier studies; these include the croaker Micropogonias undulatus, rough silverside Membras martinica and northern pipefish Syngnathus fuscus. Conversely, the weakfish Cynoscion regaljs was rare in our collections as compared to main channel sampling areas. Our results suggest that SAV areas do not play an important nursery role for pelagic eggs and early larvae, which may suffer increased predation by planktivores in these areas. Later stages, however, may benefit from reduced predation pressure from piscivores and thus benefit from association with SAV

Phylogeny Of Lampridiform Fishes

A survey of characters defining the Neoteleostei, Eurypterygii, Ctenosquamata, Acanthomorpha, Paracanthopterygii and Acanthopterygii convincingly places the Lampridiformes within the acanthomorph clade. Lampridiforms are primitive with respect to the Percomorpha but their precise placement among basal acanthomorphs remains unclear. In the absence of a specific sister-group hypothesis, Polymixia, percopsiform and beryciform taxa were used as outgroups in a cladistic analysis of the order. Monophyly of Lampridiformes is supported by four apomorphies; three are correlated modifications related to the evolution of a unique feeding mechanism in which the maxilla slides forward with the premaxilla during jaw protrusion. The Veliferidae are the sister group of all other lampridiforms. The deep-bodied (bathysomous) lampridiforms are not monophyletic because Lampris is the sister group of the elongate (taeniosomous) families. Stylephorus is placed as the sister group of all other taeniosomous families. The Radiicephalidae are hypothesized to be the sister group of the Lophotidae, a clade that forms the sister group of the Replecidae + Trachipteridae. Ateleopodid, mirapinnid, and eutaeniiophorid fishes are not lampridiforms. DaggerBajaichthys is allied with living lampridiform fishes but daggerPharmacichthys is not a lampridiform. The affinities of daggerAipichthys and daggerBathysomous are unknown

Introduction to the proceedings of the symposium Fish Larvae and Systematics: Ontogeny and relationships

The International Larval Fish Conference was held in Sydney, Australia (26- 30 June 1995) as part of the 19th Annual Meeting of the Early Life History Section of the American Fisheries Society. At the conference, we convened a symposium ( Fish Larvae and Systematics: Ontogeny and Relationships ) that was intended to stimulate the application of ontogenetic data to solve problems in fish systematics. The brief we gave the contributors to the symposium was this: The theme of this symposium will be the use of information gained from egg and larval ontogeny in solving problems in systematics and phylogeny. Thus, we are seeking, not papers that just described larval development of various taxa (although we anticipate many papers will include this), but papers which go beyond description and use the larval characters, developmental patterns, etc. to attack problems in fish systematics. For example, we would welcome papers on how larval morphology solved problems of cryptic species amongst adults, or papers that made use of ontogenetic information to assess relationships at species, genus, family or higher level. Twenty-one papers by authors from 10 countries were presented at this successful symposium

Observations On Structure And Evaluation Of Possible Functions Of The Vexillum In Larval Carapidae (Ophidiiformes)

Elongate dorsal appendages adorn pelagic larvae of many fishes from disparate taxa, among them larvae of the family Carapidae, wherein the singular, elongate appendage is termed a vexillum, The vexillum is a complex larval specialization of the dorsal fin and is characteristic of all carapid genera, It is motile, well vascularized, and innervated by a branch of a cranial nerve with no apparent spinal innervation. Histological studies of Echiodon dawsoni and Carapus bermudensis vexilla show a two layered epidermis with mucous cells, an arteriole and venuole, two myelinated peripheral nerve fascicles, and two collagenous central shafts. No taste buds, free neuromasts or organized chemoreceptors were found on the vexillum, including its fleshy tabs; collateral branches of the nerve fascicles may end as free-nerve endings. In situ observations of living pearlfish larvae revealed a remarkably long and ornamented vexillum that assumed variable postures. The data suggest that carapid vexilla serve multiple functions, including predator deception, sensation, and hydrodynamic effects

Asymmetric recurrent laryngeal nerve conduction velocities and dorsal cricoarytenoid muscle electromyographic characteristics in clinically normal horses

The dorsal cricoarytenoid (DCA) muscles, are a fundamental component of the athletic horse’s respiratory system: as the sole abductors of the airways, they maintain the size of the rima glottis which is essential for enabling maximal air intake during intense exercise. Dysfunction of the DCA muscle leads to arytenoid collapse during exercise, resulting in poor performance. An electrodiagnostic study including electromyography of the dorsal cricoarytenoid muscles and conduction velocity testing of the innervating recurrent laryngeal nerves (RLn) was conducted in horses with normal laryngeal function. We detected reduced nerve conduction velocity of the left RLn, compared to the right, and pathologic spontaneous activity (PSA) of myoelectrical activity within the left DCA muscle in half of this horse population and the horses with the slowest nerve conduction velocities. The findings in this group of horses are consistent with left sided demyelination and axonal loss, consistent with Recurrent Laryngeal Neuropathy (RLN), a highly prevalent degenerative disorder of the RLn in horses that predominantly affects the left side. The detection of electromyographic changes compatible with RLN in clinically unaffected horses is consistent with previous studies that identified “subclinical” subjects, presenting normal laryngeal function despite neuropathologic changes within nerve and muscle confirmed histologically

Financial risk tolerance of Chinese American families

This chapter investigates the factors that affect financial risk tolerance of Chinese American households. Research on the economic well-being of Chinese American households is extremely limited. Few national datasets differentiate Chinese Americans from other race/ethnicity groups. For this study, a survey of Chinese American households residing in Midwestern states was conducted. The results showed that about 80.5 % of the sample households expressed a willingness to take at least some financial risks. Factors that have an impact on financial risk tolerance of Chinese American households included gender, non-financial assets, income, and investment time horizon. Chinese Americans represents a small but fast-growing population in the USA. More research should be done to better serve the financial needs of this group.Includes bibliographical references

Balanced translocation linked to psychiatric disorder, glutamate and cortical structure/function

Rare genetic variants of large effect can help elucidate the pathophysiology of brain disorders. Here we expand the clinical and genetic analyses of a family with a (1;11)(q42;q14.3) translocation multiply affected by major psychiatric illness and test the effect of the translocation on the structure and function of prefrontal, and temporal brain regions. The translocation showed significant linkage (LOD score 6.1) with a clinical phenotype that included schizophrenia, schizoaffective disorder, bipolar disorder, and recurrent major depressive disorder. Translocation carriers showed reduced cortical thickness in the left temporal lobe, which correlated with general psychopathology and positive psychotic symptom severity. They showed reduced gyrification in prefrontal cortex, which correlated with general psychopathology severity. Translocation carriers also showed significantly increased activation in the caudate nucleus on increasing verbal working memory load, as well as statistically significant reductions in the right dorsolateral prefrontal cortex glutamate concentrations. These findings confirm that the t(1;11) translocation is associated with a significantly increased risk of major psychiatric disorder and suggest a general vulnerability to psychopathology through altered cortical structure and function, and decreased glutamate levels