Marine Biology Commons^™

Desperate Coral Larvae? Behavioral Responses To Settlement Cues In Aging Agaricia Agaricites Larvae, Helena Sasha Fulmore

HCNSO Student Theses and Dissertations

The global stressors of ocean warming and acidification, as well as local stressors such as eutrophication, overfishing, and coastal construction, have all contributed to the severe decline in coral populations worldwide. Recovery of coral reefs depends partly on recruitment, which relies on the response of larvae to settlement cues indicative of habitat quality; however, it remains unclear whether recruitment in disturbed areas will be compromised. Specifically, as reefs become more disturbed and dominated by macroalgae, it is important to understand larval behavior in response to changes in habitat quality. In this study, we first assessed the settlement success of newly …

Indirect Effects Of Ocean Warming And Acidification On The Realized Recruitment Of Agaricia Agaricites, Allan Anderson

HCNSO Student Theses and Dissertations

Over the past few decades, coral cover has declined worldwide due to overfishing, disease, and storms, and these effects have been exacerbated by ocean warming and acidification. Corals are extremely susceptible to these changes because they are already living close to their thermal and aragonite saturation thresholds. Ocean warming and acidification (OAW) may also impact coral survival and growth by impacting their settlement cues. Coral larvae use crustose coralline algae (CCA) and their associated biofilms as cues for settlement, i.e., habitat selection. Settlement cues can also be negatively affected by increased water temperature and acidity. It was hypothesized that the …

Efficacy Of Magnesium Enriched Artificial Substrate For Oyster Restoration, Matthew Elder

Masters Theses, 2010-2019

The eastern oyster, Crassostrea virginica, is a keystone species that has undergone a large (> 95%) population decline due to overharvest, pollution, and disease. Restoration efforts focus on alternative larval attachment substrates such as concrete, to supplement the loss of natural oyster shell. Magnesium is a component of bivalve shells and its presence in the environment has shown to be important to the growth of mussels, but the same relationship has not been studied in oysters. Assuming that magnesium can be assimilated from the substrate on which the organism is growing, or that ions of magnesium are leached into …

Divergent Responses Of Larval And Juvenile Blue Mussels To Low Salinity Exposure, Melissa A. May

Electronic Theses and Dissertations

In this study, we compared the osmotic stress response of larval and juvenile blue mussels (Mytilus edulis) at the transcriptomic, metabolomic, and whole organism levels. Blue mussels inhabit coastal areas, where they face climate-induced reductions in nearshore salinity. Despite their ecological and economic importance, scientists do not fully understand the underlying transcriptomic and cellular mechanisms of the osmotic stress response in blue mussels or how the ability to respond to stress changes throughout development. Blue mussels spend the first weeks of life developing through several larval stages in the plankton. These early life history stages are more vulnerable …

The Effect Of Calcium In Artificial Substrates For Oyster Restoration: Implications For The Mitigation Of Oyster Population Decline, Jessie Mandirola

Masters Theses, 2010-2019

Oyster populations in the Chesapeake Bay have declined by 99% over the past 150 years due to overharvesting, disease, ocean acidification, and poor water quality. Restoration efforts are needed to reestablish native oyster populations. Current restoration efforts utilize natural oyster shells but these methods are expensive and unsustainable. Therefore, restoration is starting to use artificial substrates instead. Concrete has been successfully used in previous research; spat will attach and oysters will grow. However, there is a lack of knowledge about how the composition of concrete effects oyster larval recruitment. We tested concrete made with limestone sand (“special concrete”) to increase …

Transgenerational Effects Of Thermal Stress: Impacts On And Beyond Coral Reproduction, Alyson Kuba

HCNSO Student Theses and Dissertations

Ocean warming causes stress to corals and records reveal that periods of thermal stress are increasing in frequency and severity. Previous studies show that thermal stress negatively impacts the reproductive output of corals. However, the transgenerational impacts of coral bleaching have never been quantified. As a consequence, it is unclear how ocean warming may alter population dynamics due to effects on reproduction and recruitment. This study quantified the transgenerational impacts of thermal stress in Montastraea cavernosa. To assess transgenerational effects of temperature stress during gametogenesis, colonies were exposed to elevated temperature for two weeks four months prior to spawning, …

Factors Contributing To Interannual Variability In The Abundance Of Bay Anchovy (Anchoa Mitchilli) Larvae, Steven B. Vega Jr.

Theses and Dissertations

Coastal ecosystems have been subject to increasing stressors over recent decades due to coastal development, human population growth, and climate change. Improving scientific understanding of the environmental factors which influence the productivity of fish populations in coastal ecosystems is vital to their prudent management, especially as the potential influence of anthropogenic climate change grows. Estuaries serve as critical habitats for many fishes of primary ecological, economic, and recreational importance. One such fish, the planktivorous Bay Anchovy (Anchoa mitchilli), is abundant along the Atlantic and Gulf coasts of the US and is a key prey resource for many estuarine and coastal …

The Growth And Bioenergetics Of Callinectes Sapidus Larvae And The Effects Of Diet Quality On Larval Physiology, James J. Pletl

OES Theses and Dissertations

Food quality, especially ω3 polyunsaturated fatty acids (PUFA), can affect the physiology and metabolic efficiency of larvae of the blue crab, Callinectes sapidus. These affects may correlate with success in development and juvenile recruitment.

Larvae were exposed to two diets differing quantitatively in ω3 PUFA and respiration, excretion, growth, and feeding rates were measured for each larval stage and the megalopal stage. The energy partitioned to molts and specific dynamic action was also measured. T

he ω3 PUFA enriched diet resulted in a lower respiration rate when compared to the unsupplemented diet, but there was little differences in excretion …

A Histological Investigation Of The Larval Mandibular Organ In The Mud Crab Rhithropanopeus Harrisii (Gould) (Crustacea Decapoda Xanthidae), Lore Lynn Hantske

OES Theses and Dissertations

Mandibular organs of the mud crab, Rhithropanopeus harrisii (Gould) were histologically located and followed throughout the larval cycle to determine their role in metamorphosis. Specimens from each day of the four larval stages and the megalopa stage were embedded in paraffin, sectioned at 8 μm, stained and observed under the microscope for the mandibular organs. The organs were located in the mandibular area of second, third and fourth stage larvae. The organs were probably present in the first stage zoeae and in the megalopa stage, although the

techniques of the study were not sensitive enough to observe them. The …

The Seasonality Of Occurrence Of Larval And Juvenile Sciaenids In A Virginia Seaside Estuary, James Howard Cowan Jr.

Biological Sciences Theses & Dissertations

The seasonality of occurrence and relative abundance of larval and juvenile fishes, particularly members of the family Sciaenidae, from a Virginia seaside estuary were determined from ichthyoplankton and trawl collections made from March 1979 to March 1980.

The larvae of 20 species distributed among 15 families were identified from the ichthyoplankton. Larvae of the bay anchovy, Anchoa mitchilli, and the Atlantic silverside, Menidia menidia, dominated the samples and made up 57 and 34%, respectively, of all larvae collected. Peak occurrence began in May and continued through August. Fish larvae were present in the study area all year.

Twenty-eight …

The Effects Of Elevated Calcium Chloride And Magnesium Chloride Levels On Larval Growth And Survival Of Macrobrachium Rosenbergii (De Man) (Decapoda Palaemonidae) Reared In The Laboratory, James Thomas Michaels Ii

OES Theses and Dissertations

The effects of elevated CaCl₂ , MgCl₂ , combination CaCl₂ and MgCl₂ concentrations and their associated ionic strengths on larval growth and survival of the freshwater prawn, Macrobrachium rosenbergii were investigated in the laboratory. Larvae were reared in diluted seawater of 15 parts per thousand salinity with elevated calcium concentrations of 330 parts per million and elevated magnesium concentrations of 1275 parts per million. Control larvae were also reared with elevated NaCl concentrations to duplicate the ionic strength increases of the combination CaCl₂ - MgCl₂ test solution which had the highest ionic strength. A …

The Spatial And Temporal Distribution Of Fish Eggs And Larvae In Hempstead Bay Estuary, Joseph Adelard Lessard

OES Theses and Dissertations

The ichthyoplankton of Hempstead Bay estuary was sampled from December 1972 to mid March 1974. Eleven stations were sampled by towing a 0.5 meter diameter plankton net. Eggs were most abundant during June and July with an average concentration calculated to be above 5,500/100m³. Egg densities were the lowest during the fall and winter. Larvae were most frequently taken from March through July with densities varying greatly among the samples. The eggs of Brevoortia tyrannus, Anchoa mitchilli, Tautoga onitis, Tautogolabrus adspersus, and Scophthalmus aguosus and the larvae of Menidia menidia, Ammodvtes hexapterus and Pseudopleuronectes americanus constituted most …

Description Of The Larval Development Of Squilla Empusa Say (Crustacea Stomatopoda) With Aspects Of Larval Ecology In Chesapeake Bay, Steven Gaines Morgan

OES Theses and Dissertations

Larvae of Sguilla empusa were collected from the plankton and were reared in the laboratory to describe the pelagic larval development and the postlarval stage. Nine pelagic stages are passed through before the postlarval stage is attained.

The larvae reared for descriptive purposes were subjected to sixteen combinations of temperature and salinity to determine their tolerance to the two parameters. Larvae survived longer and molted more frequently when reared at 25°/oo and 20°C or 25°C, which corresponds to the natural conditions of the Chesapeake Bay when the larvae were collected.

A three year planktonic survey conducted in the lower region …

A Baseline Study On The Possible Mechanisms Of Larval Stomatopod Distribution On The Carolina Shelf, Carl Robert Berman Jr.

OES Theses and Dissertations

The South Carolina Marine Resources Institute provided the author with 198 station samples containing 2,193 stomatopod larvae. These larvae had been collected during ichthyoplankton Bongo tows on five separate cruises aboard the Institute's vessel R/V DOLPHIN (February, 1972 to January, 1975). The larvae were examined microscopically and divided into early, middle, and late stages according to known growth criteria. The larval distribution was plotted geographically, by seasons, and larval density (larvae/m3) was graphed against distance offshore. Using these data, together with the circulation characteristics on the Carolina Shelf, significant distributional data appeared which supported the hypothesis that the stomatopod population …

Larval Development And Feeding Ecology Of Hermissenda Crassicornis (Eschscholtz) And Aeolidia Papillosa (Linnaeus), Leslie G. Williams

University of the Pacific Theses and Dissertations

Thompson (1967) defines three developmental types for Opisthobranchia with representative nudibranchs in each category. The types are: 1.) planktotrophic larvae which are obligatory plankton feeders prior to progressive metamorphosis, 2.) lecithotrophic larvae which may feed on the plankton, but do not need to do so in order to metamorphose, 3.) direct development which results in hatching of a post veliger, benthic juvenile.

Tardy (1970) feels that Thompson's Type 3 development is artificial. Thus, he incorporates direct development into the lecithotrophic developmental type. Tardy then proposes a classification of metamorphic types based on larval shell type (Thompson, 1961) and on larval …