Marine Biology Commons^™

Evaluation Of Long Term Changes In The Macrobenthic Community Of The Southern Branch Of The Elizabeth River, Virginia, William S. Hunley

Biological Sciences Theses & Dissertations

Long-term changes in the macrobenthos of the Southern Branch of the Elizabeth River, Virginia were investigated by comparing the present study of community structure with that described ten years earlier by Hawthorne (1980). The results indicated that dominant organisms remained relatively constant in composition but exhibited considerable fluctuation in density. Differences in diversity and spatial distribution of fauna were also observed relative to the previous decade.

Multivariate statistical analyses indicated the macrobenthos exhibited significant spatial and seasonal patterns. Sediments characterized as silts and clays predominated down river while sandier sediment types were most common farther upriver. The spatial distributions of …

Benthic Microalgal Production At Stellwagen Bank, Massachusetts Bay, Usa, Lawrence B. Cahoon, Guy R. Beretich Jr., Carrie J. Thomas, Amy M. Mcdonald

OES Faculty Publications

Benthic microalgal chlorophyll a and production were measured at 3 sites at Stellwagen Bank, a cold temperate continental shelf habitat in Massachusetts Bay, USA, during August 1991. Benthic microalgal chlorophyll a averaged 39.8 Mg M^-2, vs average integrated phytoplankton chlorophyll a of 25.9 mg m^-2. Gross benthic microalgal production, measured by oxygen exchange in clear and opaque benthic chambers, averaged 20.9 mg C m^-2 h^-1. This production was supported by average daily light fluxes to the bottom that never exceeded 1 % of surface incident radiation and were as low as 4.7 μE …

Changes In The Sea-Ice Brine Community During The Spring-Summer Transition, Mcmurdo Sound, Antarctica .2. Phagotrophic Protists, Diane K. Stoecker, Kurt R. Buck, Mary Putt

OES Faculty Publications

The land-fast sea-ice brine contains a diverse phagotrophic protist assemblage consisting of < 5 mum heterotrophic flagellates, Cryothecomonas spp., heterotrophic dinoflagellates, and heterotrophic and mixotrophic ciliates. Fine-scale horizontal spatial variability is a feature of this assemblage; samples taken within 1 m of each other can be dominated by different heterotrophic protists. Many of the larger heterotrophic protists found in the brine are also found in the water column. The photosynthetic ciliate Mesodinium rubrum is also common. In mid to late austral spring, the heterotrophic assemblage accounts for ca 10% of the total protist biomass in the brine and is dominated by Cryothecomonas spp. This flagellate …

Observations On The Pearl Oyster Fishery Of Kuwait, S. M. Almatar, Kent E. Carpenter, R. Jackson, S. H. Alhazeem, A. H. Alsaffar, A. R. A. Ghaffar, C. Carpenter

Biological Sciences Faculty Publications

The pearl oyster fishery of Kuwait was monitored daily from January 1989 to May 1990. Landings of pearl oysters in 1989 totaled 287 tons with a market value of U.S. $1.0 million. Commercial pearls (>3 mm) were estimated to be present in one of every 4200 oysters. Most of the pearl oysters landed were new recruits with hinge lengths between 40-56 mm. There was a curvilinear relationship between total weight and size of oysters (length) and the sex ratio approached 1:1. Spawning occurs throughout the year, with a spat settlement peak in early fall. Over the size range examined …

A Multivariate Characterization Of Assemblages Of Planktonic Mysids Decapods And Sergestids In The Chesapeake Bay Mouth Area, John Charles Seibel

Biological Sciences Theses & Dissertations

This study is the first to focus on the assemblages of the planktonic mysids, decapods, and sergestids found in the lower Chesapeake Bay. The assemblages of these organisms in the lower Chesapeake Bay and nearby shelf were characterized using three different statistical approaches, and the methods used were evaluated for their effectiveness at delineating ecologically meaningful assemblages. Three stations were sampled across the Chesapeake mouth and one offshore, with oblique and neuston net tows. Twenty-seven larval stages, representing at least 23 species, were found in sufficient numbers to be analyzed statistically. The statistical approaches were each based upon a different …

Seasonal Phytoplankton Development Within Three Rivers In The Lower Chesapeake Bay Region, Harold G. Marshall, Lewis F. Affronti

Biological Sciences Faculty Publications

The seasonal and inter-annual concentrations of phytoplankton were studied over a 50 month period in the lower James, York and Rappahannock Rivers (USA). Differences in the onset, duration and magnitude of major seasonal growth periods varied from year to year. There was a tendency for spring, summer and fall maxima, with a winter period of reduced abundance. An additional study of picoplankton over a 12 month period indicated greatest abundance during summer and fall, with least development in winter.

Population Ecology Of Polydora Ligni (Polychaeta: Spionidae). I. Seasonal Variation In Population Characteristics And Reproductive Activity, Roman Zajac

Biology and Environmental Science Faculty Publications

A population of the polychaete Polydora ligni Webster was studied during 1982 and 1983 in Alewife Cove, Connecticut, USA, to determine seasonal changes in population characteristics. During early spring (March and April), the population was comprised of primarily large adults that had over-wintered. Females in this group exhibited the highest mean individual fecundity over the year (> 2000 larvae per brood). However, total larval production at this time was low (5200 to 208 000 larvae m^-2 per 14 d) due to low densities of adults. Population density increased slowly during spring as juveniles produced by overwintering adults recruited into …

Population Ecology Of Polydora Ligni (Polychaeta: Spionidae). Ii. Seasonal Demographic Variation And Its Potential Impact On Life History Evolution, Roman Zajac

Biology and Environmental Science Faculty Publications

Seasonal demographic variation was studied in an estuarine population of the opportunistic polychaete Polydora ligni between May 1982 and November 1983 in Alewife Cove, Connecticut, USA. The demography of 15 cohorts settling during this period was analyzed using life cycle graph models. Cohorts settling in spring and early summer had the shortest life spans (≈ 10 wk); highest survivorship over all life cycle stages and adult females produced an estimated maximum of 6 larval broods. Early adult stages contributed most to population growth during this period, and the potential for population growth, λ, was the highest during the study. Late …

A Laboratory Study Of Predation On The Trinidadian Guppy, Poecilia Reticulata, By Two Natural Piscine Predators: Effects Of Predator Size, Prey Size, And Habitat Complexity, Hayden Thomas Mattingly

Biological Sciences Theses & Dissertations

Test populations of different-sized guppies, Poecilia reticulata, were exposed to individuals of two natural predatory species, the pike cichlid Crenicichla a/ta and the killifish Rivulus harti, under conditions of varying prey (guppy) density and habitat complexity in the laboratory. Rivulus fed most frequently on newborn and juvenile guppies < 14 mm. Crenicichla consumed more and larger guppies than did Rivulus. The mean guppy size eaten by Crenicichla was dependent on the length of the individual predator, but as a group, the 15 Crenicichla tested were non-selective with respect to guppy size and gender. The prey gender preference of Rivulus could not he determined …

Community Structure Of The Macrobenthos In Back Bay, Virginia, Michael F. Lane

Biological Sciences Theses & Dissertations

A study of the subtidal macrobenthos in Back Bay, Virginia was conducted to examine community structure in relation to sedimentary and water quality characteristics. Samples were collected in August and November of 1987 and February and May of 1988 at ten stations.

Three site groups and three temporal groups were identified by cluster analyses of species abundance. Species composition between site groups was relatively homogeneous and eight species accounted for most of the variation between site groups. A comparison of plots of the biological and physical data in discriminant space suggested that variations in the biological data between site groups …

The Future For Recreational Fishing Final Report Of The Recreational Fishing Advisory Committee, Recreational Fishing Advisory Committee

Fisheries Management Papers

This report discusses: What Recreational fishing means to Western Australia's estimated 300,000 fishers. Conservation and equality in catch sharing was at the heart of the Committee's investigations into developing strategies for the future management of important recreational fish stocks.

Development And Evaluation Of Tracer Particles For Use In Microzooplankton Herbivory Studies, Mary Putt

OES Faculty Publications

Two methods of preparing algae for use as tracer particles in single species measurements of microzooplankton herbivory were evaluated. Algae were either heat-killed and labelled with 5-(4,6-dichlorotriazin-2-yl amino fluorescein) (DTAF) (Rublee & Gallegos 1989; Mar, Ecol. Prog. Ser. 51: 221-227) or stained with hydroethidine (HYD). Both DTAF and HYD-stained algae were readily visible within the digestive vacuoles of most microzooplankton collected in estuarine and coastal waters of Massachusetts (USA) and preserved with Lugol's iodine. However, DTAF was ineffective at staining several chromophytic algae and the heat-kill process reduced cell volume by ≥ 50% in several of the algae which were …

Observations Of The Phytoplankton Standing Crop At The Shelf Margin Of The Mid Atlantic Bight, Bruce B. Wagoner, Harold G. Marshall

Biological Sciences Faculty Publications

A comparison of the total percentage cell abundance and cell biovolume relationships of major phytoplankton categories was made between two station sets across the shelf margin. Diatom values for abundance and biovolume were greater at oceanic stations compared to the outer shelf stations, with dinoflagellates having the reverse pattern. The composite contributions to biovolume and abundance in the standing crop from other phytoplankton categories were greater over the outer shelf than beyond the shelf margin. The major source of biovolume (biomass) from the outer shelf and these oceanic stations came from the diatoms and dinoflagellates, with an average mean of …

Fisheries Research Report No. 89 - Relationships Among Partial And Whole Lengths And Weights For Western Australian Pink Snapper Chrysophrys Auratus (Sparidae), M. J. Moran, C. Burton

Fisheries Research Reports

Pink snapper, Chrysophrysauratus (Sparidae) is one of the major commercial and recreational fish in Western Australian inshore waters. This report presents a number of equations and conversion factors for management and scientific study of the species. Equations to calculate total lengths from partial lengths will facilitate enforcement of minimum legal lengths when snapper are landed in a "head-off" condition. For fisheries science purposes, there are equations to convert among total length, standard length and length to caudal fork; and to convert lengths and weights of processed fish to whole lengths and weights. Length-weight relationships are presented and compared with those …

Fisheries Research Report No. 84 - The Marine Open Shelf Environment: Review Of Human Influences, D. A. Hancock

Fisheries Research Reports

For the purpose of this review, the marine environment has been classified into three physical zones - the littoral zone, the open-shelf environment and the coral reef. Since the boundaries are arbitrary, there will inevitably be some overlap, but for this review the subject matter will be related to the area between low water of ordinary spring tides and the edge of the continental shelf; i.e., to a depth varying to 200 metres.

Human influences may have a dual role in affecting the marine environment, firstly in a causative manner and secondly in providing a remedy, in which case the …

Freshwater Fishes Of Shipstern Nature Reserve, Caspar F. A. Bijleveld

Physiology Faculty Research Publications

A survey of fishes in and around Shipstern Nature Reserve in Northern Belize, Central America, was carried out over a period of eight months, from February to September 1990. Its purpose was to establish a preliminary list of the fishes of Shipstern Nature Reserve, including descriptions, distribution and collecting data and additionally to describe some of the habitats in which the fishes were found. This study focuses on fishes considered to be freshwater species. These occurred for the greater part in brackish habitats. Nevertheless, a few fish considered as marine species were caught in the waters of the reserve and …

Natural And Disturbance-Induced Demographic Variation In An Infaunal Polychaete, Nephtys Incisa, Roman Zajac, Robert B. Whitlatch

Biology and Environmental Science Faculty Publications

Demography of the infaunal polychaete Nephtys incisa was investigated for periods of 1 yr prior to and following disturbance (dredge material disposal) at a site in central Long Island Sound, USA. Infaunal grab samples were taken at 5 stations 200 m to 3 km apart. The demography of populations at each station was based on age-classes spanning juveniles to adults 4 + yr of age. Age-specific survivorship and fecundity were based on changes in mean density of each cohort and a positive correlation between female size and egg production, respectively. Analyses of population matrix models indicated pre-disposal populations had positive …

Effects Of Inter-Specific Density And Food Supply On Survivorship And Growth Of Newly Settled Benthos, Roman Zajac, Robert B. Whitlatch, Richard W. Osman

Biology and Environmental Science Faculty Publications

Using a laboratory model system comprised of newly settled oysters Crassostrea virginica and established fouling species (Botrylloides sp. initially, and others including Styela clava and Ciona intestinalis as the experiment progressed), we tested how differences in food supply and competitor density may affect post-settlement surivorship and growth of sessile marine invertebrates over a 44 d period. After 15 d, results were mixed but indicated that both food and density conditions affected growth and survivorship significantly, with some suggestion of high food levels ameliorating high density effects However, 44 d after settlement, oysters had reduced survivorship and growth when competitors …

Distribution And Marketing Of Western Australia Rock Lobster., P. J. Monaghan

Fisheries Management Papers

This report describes the marketing and distribution of Western Australian rock lobster products in the major consuming countries namely, USA, Japan and Taiwan. It is based on a study which was commissioned by the Fisheries Department of Western Australia who sought, for the benefit of industry generally, an understanding of the world lobster markets.

Picoplankton/Phytoplankton Dynamics In Hampton Roads, Virginia, Leslie E. Dorworth

OES Theses and Dissertations

The biomass distribution of the three main size components of the phytoplankton (net, nano, and picoplankton) was examined in the lower Chesapeake Bay. Work was done at two stations during the spring and neap tidal cycles when freshwater flow into the bay was at its seasonal minimum and maximum. Emphasis was placed on how the picoplankton ( < 2.0 μm, > 0.2 μm) reacted during the sampling period.

Picoplankton made up approximately 13% of the total biomass, during the observed time period, at the more oceanic station. The picoplankton fraction contributed up to 16% of the total biomass at the estuarine station. From this …

Effects Of Resident Species On Recruitment Into A Community: Larval Settlement Versus Post-Settlement Mortality In The Oyster Crassostrea Virginica, Roman Zajac, Richard W. Osman, Robert B. Whitlatch

Biology and Environmental Science Faculty Publications

Laboratory and field experiments revealed that a variety of species of common, sessile invertebrates, including barnacles, ascidians, and bryozoans, affected the settlement and post-settlement abundance of the oyster Crassostrea virginica (Gmelin). While the nature of the effects varied, most species both reduced oyster settlement by covering and removing substrate available for attachment, and increased settlement on adjacent surfaces. The solitary ascidians Ciona intestinalis (L.) and Styela clava (Herdman), were found to be predators of oyster larvae. Post-settlement survivorship and growth were also strongly affected by the presence of sessile species. In most cases the effects were negative and correlated with …

Southern Demersal Gillnet And Longline Fishery., Management Advisory Committee

Fisheries Management Papers

In its report to the Ministier for Fisheries in November 1986, the Southern Western Australian Shark Working Group recommended the establishment of an Industry/Government Mangement Advisory Committee to provide managememt advice on the fishery to the Minister for Fisheries. The Advisory Committee held its first meeting in Albany on 23 February 1989. After being briefed on the state of shark stocks, the Committee's deliberations fell into three broad categories. In the first category there was sufficient time and information available to make a recommendation to the Minister for Fisheries. In the second category, discussion commenced, but was held over to …

Management Of The Perth Metropolitan Purse-Seine Fishery., N. Moore

Fisheries Management Papers

This report outlines the management plan for the limited entry purse-seine fishery for small pelagic fish in coastal waters between Lancelin and Cape Bouvard and seaward to the 200 mile limit of the Australian Fishing Zone. The plan includes Cockburn Sound.

A Review Of The Shark Bay Pearling Industry., D. A. Hancock

Fisheries Management Papers

While there are currently only two pearl culture leases in Shark Bay, two new applications for leases have already been received by the W.A. Fisheries Department. Increased interest is being generated about pearl culture in Shark Bay, which will need to be considered against the background of management plans designed to restrict further entry into other areas, notably the pearly industry of W.A from Exmouth Gulf northwards, and the pearling industry of the Northern Territory. Recent successes with pearl culture in both those areas, and the greatly increased revenues and high lease transfer values realised, must inevitably focus interest on …

Fisheries Management Paper No.23 - Management Of The South-West Inshore Trawl Fishery., N. Moore

Fisheries Management Papers

This report outlines the management plan for the south west inshore trawl fishery which already operates in coastal waters less than 200 metres deep between Guilderton and Cape Leeuwin.

This management plan takes into account these important concerns and has specifically set aside a strip of coastal area from Cape Bouvard to Cape Leeuwin for recreational usage and for protection of the benthic community, and closed the management zone north of Burns Beach to trawling.

A Report On Marron Fishing In Western Australia., Doug Wenn

Fisheries Management Papers

The marroning experience is one enjoyed by many Western Australians. A rapid increase in fishing effort evidenced by the increase in number of recreational fishing licences issued, combined with low rainfall in the last few years resulted in a dramatic reduction of marron catch rates during 1986/87. In view of the state of marron stocks, the Minister for Fisheries considered it appropriate to close the 1987/88 marron season.

Survey And Reconnaissance Of Sea Turtles In The Northern Gulf Of Mexico, Larry Ogren

United States Department of Commerce: Staff Publications

This is a report on the results of an aerial survey of nesting beaches conducted during the period from May 16, 1977 to August 11, 1977. The area covered included the barrier beaches and offshore islands from the Florida-Alabama state line to the Rio Grande, Texas. Additional historical information is provided in order to compare current nesting activity with previous years as well as anecdotal observations on the occurrence of sea turtles in this region.

Rock Lobster Industry Advisory Committee Report To The Minister For Fisheries., Rock Lobster Industry Advisory Committee

Fisheries Management Papers

The total catch of about 12.1 million kilograms for the 1987/88 season, based on processor returns, was an increase of 44% on the 1986/87 season. This very high catch, the third highest on record, resulted from an above average perulus settlement in 1983/84 and a "flow-on" of fast growing animals stemming from the expected high recruitment in 1988/990 caught as "reds" in 1987/88.

The Committee has identified five major elements related to the state of the rock lobster fishery upon which management advice is considered.

a) The undersize fraction of the population.

b) The "whites" which provide a significant proportion …

Community Responses To Variable Predation: Field Studies With Sunfish And Freshwater Macroinvertebrates, Mark J. Butler Iv

Biological Sciences Faculty Publications

The impact of variable predation by bluegill sunfish on macroinvertebrate prey in a North Florida lake is examined. Variable predation may occur in many systems and may contribute substantially to the spatial heterogeneity, temporal inconstancy and species composition of prey communities.

Patchy, temporally variable predation characterized middepth and deep lake habitats, whereas in the shallow zone predation was relatively constant and homogeneous. Predation varied significantly every 2-4 wk in the mid-depth zone, but varied little between consecutive weeks or days. Caging experiments revealed that variable predation altered prey community composition and increased the mean size and size range of some …

Vertical Distribution Of Phytoplankton Populations Along The Northeastern Continental Shelf Margin Of The United States, Bruce Burwell Wagoner

Biological Sciences Theses & Dissertations

A study of phytoplankton vertical distribution at six stations along the northeast continental shelf of the United States was conducted in April 1984.

A total of 168 taxa were identified from nine phylogenetic groups collected at depths up to 150 m. Highest cell concentrations and cell volumes were in the upper 30 m. Greatest cell concentrations were produced by diatoms and a pico-nanoplankton component, with cell volumes mainly the product of diatoms and dinoflagellates. A high degree of variability was observed between phylogenetic groups within each station, but less variability was noted for phylogenetic categories at different stations.

Little difference …