Marine Biology Commons^™

Description Of A New Sound Produced By Nassau Grouper At Spawning Aggregation Sites, Timothy J. Rowell, Michelle T. Schärer, Richard S. Appeldoorn

Gulf and Caribbean Research

This study identified a new sound produced by Nassau Grouper in association with, although potentially not exclusive to, an agonistic interaction at a spawning aggregation. We have also provided a behavioral and acoustic description for identification of this sound in future studies. The discovery of a third type of sound produced by Nassau Grouper further highlights the importance of acoustic communication coupled with visual displays in fishes. Furthermore, identification of a new sound increases the ability to document the presence of this endangered species at spawning sites. Future efforts may reveal that the sound is produced within additional behavioral contexts …

Diel Activity Patterns And Movement Of Invasive Lionfish (Pterois Volitans/P. Miles) In The Florida Keys Identified Using Acoustic Telemetry, Michael Mccallister, Jeffrey Renchen, Benjamin Binder, Alejandro Acosta

Gulf and Caribbean Research

The invasion of Indo—Pacific lionfish (Pterois volitans/P. miles) throughout the Caribbean and southeastern U.S. Atlantic represents a significant ecological threat, yet few studies have examined the daily activity and movement patterns of this invasive species. In this study, passive acoustic telemetry was used to track lionfish at 4 coral reef sites in the Florida Keys. Fourteen lionfish were tagged among the 4 sites, and the total number of days tagged fish were detected ranged from 5 to 141 days. Hourly detection data revealed diel activity patterns with peaks at dawn and dusk. Mixed model analysis of detection data indicated a …

Characterizing Habitat Suitability For A Central‐Place Forager In A Dynamic Marine Environment, Dana K. Briscoe, Sabrina Fossette, Kylie L. Scales, Elliott L. Hazen, Steven J. Bograd, Sara M. Maxwell, Elizabeth A. Mchuon, Patrick W. Robibson, Carey Kuhn, Daniel P. Costa, Larry B. Crowder, Rebecca L. Lewison

Biological Sciences Faculty Publications

Characterizing habitat suitability for a marine predator requires an understanding of the environmental heterogeneity and variability over the range in which a population moves during a particular life cycle. Female California sea lions (Zalophus californianus) are central‐place foragers and are particularly constrained while provisioning their young. During this time, habitat selection is a function of prey availability and proximity to the rookery, which has important implications for reproductive and population success. We explore how lactating females may select habitat and respond to environmental variability over broad spatial and temporal scales within the California Current System. We combine near‐real‐time …

Characterizing Habitat Preference In Three Nearshore Reef-Associated Fishes Through Collaborative Research, Public Data, And Open Source Software, Ian D. Kelmartin

Cal Poly Humboldt theses and projects

Black rockfish (Sebastes melanops), canary rockfish (S. pinniger), and lingcod (Ophidion elongatus) are important species in Northern California’s nearshore recreational and commercial fisheries. These species are associated with nearshore rocky reefs and are among a suite of species intended to benefit from the establishment of the marine protected area (MPA) network along the Northern California Coast in 2012.

Many aspects of the North Coast’s nearshore ecosystem remain poorly studied, including the spatial distribution and habitat associations of nearshore fish species. This study used data collected from Cape Mendocino State Marine Reserve (SMR), Ten Mile …

Ecological Implications Of Foraging And Life-History In Three Cold-Adapted Species, Andrew Von Duyke

Dissertations, Master's Theses and Master's Reports

This research investigates the ecology of: ringed seals (Pusa hispida), moose (Alces alces), and bowhead whales (Balaena mysticetus). Each of these species draws upon specialized strategies to meet the physical demands of life in their extreme environments. However, they are currently experiencing unprecedented changes in their habitats. This work adds to what is known about the behavior, physiology, and population dynamics of cold-adapted species—providing insights of value for an improved understanding of foraging and life-history theory, and informing conservation and ecosystem monitoring efforts. Chapter 1 provides a brief introduction to the scope of work …

Altered Environmental Light Drives Retinal Change In The Atlantic Tarpon (Megalops Atlanticus) Over Timescales Relevant To Marine Environmental Disturbance, Lorian E. Schweikert, Michael S. Grace

Ocean Engineering and Marine Sciences Faculty Publications

For many fish species, retinal function changes between life history stages as part of an encoded developmental program. Retinal change is also known to exhibit plasticity because retinal form and function can be influenced by light exposure over the course of development. Aside from studies of gene expression, it remains largely unknown whether retinal plasticity can provide functional responses to short-term changes in environmental light quality. The aim of this study was to determine whether the structure and function of the fish retina can change in response to altered light intensity and spectrum—not over the course of a developmental regime, …

Diversity And Phylogenetic Relationships Of European Species Of Crepidostomum Braun, 1900 (Trematoda: Allocreadiidae) Based On Rdna, With Special Reference To Crepidostomum Oschmarini Zhokhov & Pugacheva, 1998, Romualda Petkevičiūtė, Virmantas Stunžėnas, Alexander E. Zhokhov, Larisa G. Poddubnaya, Gražina Stanevičiūtė

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Background

Within the genus Crepidostomum Braun, 1900, identification of species and taxonomic decisions made only on the basis of adult morphology have resulted in great problems associated with evaluating actual diversity and validity of species. Life cycle data, while equal in importance to adult characters, are scarce, controversial or incomplete for most Crepidostomum spp. In this study, rDNA sequences generated from adult and larval Crepidostomum spp. and some other allocreadiid species were analyzed to reveal the diversity and phylogenetic relationships of the species and their host range. Detailed morphological description based on light microscopy, SEM tegumental surface topography and genetic …

First Record Of The Yellowfin Soldierfish, Myripristis Chryseresjordan & Evermann, 1903, In The Easter Island Ecoregion, Erin E. Easton, Javier Sellanes, Matthias Gorny

School of Earth, Environmental, & Marine Sciences Faculty Publications

Myripristis chryseres Jordan & Evermann, 1903, is recorded for the first time in the Easter Island Ecoregion. Two specimens were observed swimming along a rock cliff and entering a cavern at ∼163 m depth near the peak of Pukao seamount, located ∼85 km (46 nm) west of Easter Island. This report expands the geographic range of M. chryseres eastward by ∼3,800 km and is the first report of the species for the eastern Pacific. It is unclear whether this new record is indicative of a relatively recent range expansion or a lack of visual surveys in the region, which …

Reducing Elasmobranch Bycatch In The Atlantic Seabob (Xiphopenaeus Kroyeri) Trawl Fishery Of Guyana, Aaron Garstin, Hazel A. Oxenford

Gulf and Caribbean Research

The Atlantic seabob (Xiphopenaeus kroyeri) trawl fishery is very important to Guyana, with 88 licensed industrial vessels harvesting about 15,000 mt annually, representing Guyana’s most valuable seafood export. All vessels are already using both teleost by—catch reduction devices (BRDs) and turtle excluder devices (TEDs) to satisfy international market standards. However, the key stakeholder, the Guyana Association of Private Trawler Owners and Seafood Processors, is now seeking to access sustainable seafood markets through pursuing Marine Stewardship Council (MSC) certification. To this end, this study documents elasmobranch by—catch in the current fishery and examines the effectiveness of a modified TED …

Preliminary Multivariate Comparison Of Coral Assemblages On Carbonate Banks In The Western Gulf Of Mexico, Rebekah E. Rodriguez, Erin E. Easton, Thomas C. Shirley, John W. Tunnell, David Hicks

School of Earth, Environmental, & Marine Sciences Faculty Publications

Hermatypic corals flourished on reefs in the Gulf of Mexico (GOM) in the late Pleistocene and early Holocene. Today, many of these relict reefs are mesophotic banks that have unique coral assemblages and provide critical habitat; however, the South Texas Banks (STB) lack quantitative surveys. Therefore, we used a remotely operated vehicle to conduct quantitative surveys of 5 banks: Baker, Aransas, Dream, Blackfish Ridge, and Harte. Coral communities, based on estimated coral densities (colonies/m2), significantly differed among banks for terraces, slopes, and overall (combined terrace and slope) communities for most banks examined. Within banks, terrace and slope communities significantly differed …

The Distribution And Trophic Ecology Of Golden Ghost Crabs (Ocypode Convexa), Caitlin Rae

Theses: Doctorates and Masters

Sandy beaches make up approximately three-quarters of the world’s shorelines. They are important ecosystems, hosting abundant invertebrate macrofaunal communities that provide food resource for vertebrate predators such as shorebirds, seabirds, marine mammals and fish. Although possessing a terrestrial appearance, food input on sandy beaches is derived predominantly from the sea. Such food input includes detrital matter, mostly in the form of wrack, and has the potential to support a great diversity of species, as well as stabilising energy fluxes and dynamics of consumer populations. The movement of detritus, along with other vectors such as organisms and nutrients, across ecosystem boundaries …

Characterization Of Vitellogenesis In The Bonnethead Shark Sphyrna Tiburo, Adrien Kathleen Mowle

UNF Graduate Theses and Dissertations

Vitellogenin (Vtg) is a precursor to yolk-proteins produced in the liver of many invertebrates and non-mammalian vertebrates; its synthesis is stimulated by the hormone estradiol (E2). This study is the first to characterize vitellogenin synthesis in a placental viviparous elasmobranch, the yolk-sac placental bonnethead shark, Sphyrna tiburo. This study focused on determining where and when Vtg is produced, as well as what hormonal factors regulate Vtg production. The liver was confirmed as the site of Vtg production via immunohistochemistry. Immunoreactivity was also observed within granulosa cells of ovarian follicles; further experimentation is needed to determine if this is indicative …

Establishing Relationships Among Environmental Stressors, Host Immune Status, And Wasting Disease Susceptibility In The Dominant Seagrass Species Thalassia Testudinum, Paige Joy Duffin

UNF Graduate Theses and Dissertations

A growing body of evidence supports the observation that marine disease outbreaks, especially those caused by opportunistic pathogens, are increasing in frequency and severity. One genus of such pathogens, Labyrinthula, has been identified as the causative agent of seagrass wasting disease, an epidemic that has historically plagued seagrass beds around the world. It is suspected that pathogenicity is intimately linked to the ability of the host to initiate defense responses, but a lack of compelling evidence prevents any meaningful application of preliminary observations. This body of work investigated the roles of host genotype, host immune status, and environmental stressors …

Reproductive Biology Of The Tiger Shark In The Western Atlantic Ocean, Chelsea Shields

UNF Graduate Theses and Dissertations

Although tiger sharks are an important apex predator in many ecosystems, little is known about their reproduction. The goal of this study was to determine the size-at-maturity and the reproductive seasonality of tiger sharks in the western Atlantic Ocean. This was achieved using a combination of ultrasonography and measurements of plasma hormone concentrations; in particular, testosterone for males and estradiol and progesterone for females. Steroid hormone concentrations were measured using chemiluminescent assays (CLIA). Maturity was also examined through histology of reproductive organs in females and clasper calcification in males. Females were found to mature between 270 and 310 cm total …

The Effects Of The Red Tide Producing Dinoflagellate, Karenia Brevis, And Associated Brevetoxins On Viability And Sublethal Stress Responses In Scleractinian Coral: A Potential Regional Stressor To Coral Reefs, David A. Reynolds

UNF Graduate Theses and Dissertations

Coral cover is in decline on a global scale, with increased mortality events being attributed to a number of global and regional stressors. While the impacts of global stressors (e.g. sea surface temperature rise, ocean acidification) are well documented, there is growing interest in identifying and understanding the impacts of regional stressors. The reason for this change in focus is that regional stressors can often work in combination, sometimes synergistically, with global stressors and that stressors on a regional scale tend to be more easily mitigated by management practices. One regional stressor that impacts a myriad of marine organisms in …

Distribution And Community Structure Of First Coast Shark Assemblages And Their Relative Trophic Niche Dynamics, Clark R. Morgan

UNF Graduate Theses and Dissertations

Nearshore marine environments are known to be highly productive systems with relatively high faunal diversity and abundances, but these systems are particularly vulnerable to negative impacts from anthropogenic disturbances that can result in habitat degradation. Despite these challenges, many shark species of various life stages utilize coastal shelf habitats, inshore estuaries, and bays. The inshore habitats of Cumberland and Nassau Sounds in northeast Florida have been proposed as potential nursery grounds by earlier work, but this suggestion did not satisfy all of the standard criteria of shark nursery designation. It has recently been stated that the combination of surveys inside …

Environmental Factors Affecting Hatch Success In The Loggerhead Sea Turtle (Caretta Caretta), Mattie J. Whitesell

College of Graduate Studies: Theses & Dissertations

The loggerhead turtle (Caretta caretta) is a species federally listed as “threatened” whose global populations are declining. Georgia Department of Natural Resources conservation protocols for this species require the daily monitoring of nesting activity and permit physical relocation of nests which are at risk of being eroded or flooded by storms and high tides in order to increase hatch success--the proportion of hatched to unhatched eggs. Relocated nests are moved to an area with higher elevation in order to avoid flooding, but other variables such as increased temperature and decreased moisture are introduced when relocating. For years temperature …

Preliminary Multivariate Comparison Of Coral Assemblages On Carbonate Banks In The Western Gulf Of Mexico, Rebekah Rodriguez, Erin E. Easton, Thomas C. Shirley, John W. Tunnell, David Hicks

Gulf and Caribbean Research

Hermatypic corals flourished on reefs in the Gulf of Mexico (GOM) in the late Pleistocene and early Holocene. Today, many of these relict reefs are mesophotic banks that have unique coral assemblages and provide critical habitat; however, the South Texas Banks (STB) lack quantitative surveys. Therefore, we used a remotely operated vehicle to conduct quantitative surveys of 5 banks: Baker, Aransas, Dream, Blackfish Ridge, and Harte. Coral communities, based on estimated coral densities (colonies/m²⁾, significantly differed among banks for terraces, slopes, and overall (combined terrace and slope) communities for most banks examined. Within banks, terrace and slope communities …

Restoration Of Visual Performance And Opsin Expression Within The Retina During Eye Regeneration In The Florida Fighting Conch (Strombus Alatus), Jamie M. Clark

Theses and Dissertations

Conch are slow-moving, herbivorous, marine gastropods that possess prominent camera-type eyes at the ends of long, flexible stalks. Compared to the eyes of other gastropods, those of conch are large (up to 1.5 mm in diameter) and have sophisticated optics that include a lens with a graded refractive index. Conch also have a remarkable ability to regenerate eye tissue: after an eye is lost, a new eye will develop to take its place within weeks. Eye regeneration in conch appears to occur rapidly compared to eye regeneration in other gastropods. Despite our knowledge of the complexity and regenerative abilities of …

On The Scattering Of Topographically Modified Semidiurnal Kelvin Waves Into Internal Waves, Tianyi Zhang

Theses and Dissertations

Semidiurnal tides propagate along continental shelves as a Kelvin wave mode. On wide continental shelves, the shelf topography modifies the Kelvin wave mode into a hybrid Kelvin-edge wave (HKEW), with features of a zero mode edge wave. Its free surface structure and alongshore energy flux concentrate on the shelf, and are sensitive to changes in the shelf width. When a propagating HKEW encounters an alongshore change of shelf width, the adjustment of wave structures results in the scattering of the incident wave into other wave modes, including barotropic and baroclinic Poincaré waves radiating offshore. These dynamics are studied using the …

Phenotypic Response Of Marine Cryptophytes To Varying Spectral Irradiance, Kristin M. Heidenreich

Theses and Dissertations

Cryptophytes are eukaryotic algae found in a variety of aquatic ecosystems, that vary in the color of light available for photosynthesis. This algal division displays a diversity in necessary photosynthetic pigments, possessing either phycoerythrin (Cr-PE; “pink”) phycocyanin (Cr-PC; “green”). According to the theory of complementary chromatic adaptation, this diversity should help maximize absorption of light within natural environments. The objective of this study was to determine if pigmentation related to growth performance in environments of differing spectral irradiance. Eight species of marine cryptophytes (5 Cr-PE and 3 Cr-PC species) were grown under four different spectral light environments. Growth rates, cellular …

Influence Of Energy Availability On The Carbon Isotopes Of Methane And Biomarkers During Hydrogenotrophic Methanogenesis, Tran Nguyen

Theses and Dissertations

Signatures of organic molecules in the environment are widely used to identify microbial metabolic processes and to track the cycling of carbon. The lipid biomarkers of methane cycling archaea are of particular interest as they are unique, preserved over geologic time scales, and reflect processes that impact an important greenhouse gas. Their isotopic compositions have been used to distinguish regions where archaea produce and anaerobically consume CH4. Previous work has demonstrated that energy availability impacts the stable carbon isotopes of CH4 during microbial synthesis from H2 and CO2. Here, we investigated whether this relationship could be extended to lipids and …

High Frequency Temperature Variability Reduces The Risk Of Coral Bleaching, Aryan Safaie, Nyssa J. Silbiger, Timothy R. Mcclanahan, Geno Pawlak, Daniel J. Barshis, James L. Hench, Gareth J. Williams, Kristen A. Davis

Biological Sciences Faculty Publications

Coral bleaching is the detrimental expulsion of algal symbionts from their cnidarian hosts, and predominantly occurs when corals are exposed to thermal stress. The incidence and severity of bleaching is often spatially heterogeneous within reef-scales (km), and is therefore not predictable using conventional remote sensing products. Here, we systematically assess the relationship between in situ measurements of 20 environmental variables, along with seven remotely sensed SST thermal stress metrics, and 81 observed bleaching events at coral reef locations spanning five major reef regions globally. We find that high-frequency temperature variability (i.e., daily temperature range) was the most influential factor in …

Sea Turtles And Survivability In Demersal Trawl Fisheries: Do Comatose Olive Ridley Sea Turtles Survive Post-Release?, Sara M. Maxwell, Matthew J. Witt, Gaspard Abitsi, Marie Pierre Aboro, Pierre Didier Agamboue, Georges Mba Asseko, Francois Boussamba, Emmanuel Chartain, Micheline Schummer Gnandji, Brice Didier Koumba Mabert

Biological Sciences Faculty Publications

Incidental capture of air‑breathing species in fishing gear is a major source of mortality for many threatened populations. Even when individuals are discarded alive, they may not survive due to direct injury, or due to more cryptic internal physiological injury such as decompression sickness. Post‑release mortality, however, can be difficult to determine. In this pilot study, we deployed survivorship pop‑up archival tags (sPAT) (n = 3) for an air‑breathing species, the olive ridley sea turtle (Lepidochelys olivacea), one of the first studies to do so. We found that at least two of the three turtles survived after being …

Integrating Dynamic Subsurface Habitat Metrics Into Species Distribution Models, Stephanie Brodie, Michael G. Jacox, Steven J. Bograd, Heather Welch, Heidi Dewar, Kylie L. Scales, Sara M. Maxwell, Dana M. Briscoe, Christopher A. Edwards, Larry B. Crowder, Rebecca L. Lewison, Elliott L. Hazen

Biological Sciences Faculty Publications

Species distribution models (SDMs) have become key tools for describing and predicting species habitats. In the marine domain, environmental data used in modeling species distributions are often remotely sensed, and as such have limited capacity for interpreting the vertical structure of the water column, or are sampled in situ, offering minimal spatial and temporal coverage. Advances in ocean models have improved our capacity to explore subsurface ocean features, yet there has been limited integration of such features in SDMs. Using output from a data-assimilative configuration of the Regional Ocean Modeling System, we examine the effect of including dynamic subsurface …

Energy-Rich Mesopelagic Fishes Revealed As A Critical Prey Resource For A Deep-Diving Predator Using Quantitative Fatty Acid Signature Analysis, Chandra Goetsch, Melinda G. Conners, Suzanne M. Budge, Yoko Mitani, William A. Walker, Jeffrey F. Bromaghin, Samantha E. Simmons, Colleen Reichmuth, Daniel P. Costa

Biological Sciences Faculty Publications

Understanding the diet of deep-diving predators can provide essential insight to the trophic structure of the mesopelagic ecosystem. Comprehensive population-level diet estimates are exceptionally difficult to obtain for elusive marine predators due to the logistical challenges involved in observing their feeding behavior and collecting samples for traditional stomach content or fecal analyses. We used quantitative fatty acid signature analysis (QFASA) to estimate the diet composition of a wide-ranging mesopelagic predator, the northern elephant seal (Mirounga angustirostris), across five years. To implement QFASA, we first compiled a library of prey fatty acid (FA) profiles from the mesopelagic eastern North Pacific. Given …

ฤดูสืบพันธุ์และนิเวศวิทยาการกินอาหารของปลาคางคก Allenbatrachus Grunniens (Linnaeus, 1758) บริเวณปากแม่น้ำปราณบุรี จังหวัดประจวบคีรีขันธ์, ทัพประดิษฐ์ มิตรเปรียญ

Chulalongkorn University Theses and Dissertations (Chula ETD)

ปลาคางคกชนิด Allenbatrachus grunniens (Linnaeus, 1758) เป็นปลาน้ำกร่อยชนิดสำคัญและมีความสำคัญต่อระบบนิเวศ ปากแม่น้ำปราณบุรี จังหวัดประจวบคีรีขันธ์ ในอดีตยังไม่มีรายงานทางด้านวิชาการถึงบทบาทและการใช้ประโยชน์ของปลาชนิดนี้ จากบริเวณปากแม่น้ำ การศึกษาครั้งนี้ จึงทำการศึกษาฤดูสืบพันธุ์และนิเวศวิทยาการกินอาหารของปลาคางคกชนิด A. grunniens บริเวณปากแม่น้ำปราณบุรี โดยทำการเก็บตัวอย่างปลาชนิดนี้ (จำนวน 111 ตัว) จาก 5 สถานี (St1-St5) ระหว่างเดือนพฤศจิกายน พ.ศ. 2559 ถึง เดือนตุลาคม พ.ศ. 2560 ผลการศึกษาพบว่าการกระจายตัวของปลา A. grunniens สามารถพบได้แค่ 2 สถานี (St4 และ St5) เท่านั น ขณะที่ปลา A. grunniens ความยาวเหยียดเฉลี่ย 17.46±3.53 เซนติเมตร ข้อมูลทางด้านสัณฐานวิทยาและมิญชวิทยาแสดงให้เห็นว่าโครงสร้างของรังไข่จัดเป็นแบบไข่สุก ไม่พร้อมกัน (asynchronous development ovary) เนื่องจากประกอบด้วยเซลล์ไข่หลากหลายระยะ ที่สามารถแบ่งออกเป็น 4 ระยะ คือ โอ โอโกเนีย ระยะการเจริญของการพัฒนาเซลล์ไข่ขั้นปฐมภูมิ ระยะการเจริญของการพัฒนาเซลล์ไข่ขั้นทุติยภูมิ และระยะปล่อยเซลล์ไข่ ในขณะที่โครงสร้างอัณฑะในปลาเพศผู้จัดเป็น unrestricted spermatogonial testis ที่สามารถพบการกระจายของระยะสเปอร์มาโทโกเนียมตลอด ความยาวของท่อสร้างอสุจิ ทั้งนี้ ระยะสเปอร์มาโทไซต์ระยะแรก ระยะสเปอร์มาโทไซต์ระยะที่สอง ระยะสเปอร์มาทิดและระยะสเปอร์มาโทซัวก็ ยังสามารถพบได้ภายในท่อสร้างอสุจิ (สำหรับสัดส่วนเพศของปลา A. grunniens เป็น 1:1) จากค่าดัชนีความสมบูรณ์เพศ (GSI), ค่าดัชนีความ สมบูรณ์ของตับ (HSI) และการเปลี่ยนแปลงร้อยละของการเจริญของอวัยวะสร้างเซลล์สืบพันธุ์ พบว่าค่าดัชนีความสมบูรณ์เพศสอดคล้องกับการ เจริญของอวัยวะสืบพันธุ์ของปลาคางคกทั้งสองเพศ พบช่วงสืบพันธุ์สองช่วง [ช่วงแรกคือ ช่วงเดือนมกราคม พ.ศ.2560 ถึงเดือนกุมภาพันธ์ พ.ศ.2560 และช่วงที่สอง คือ ช่วงเดือนกรกฏาคม พ.ศ.2560 ถึงเดือนตุลาคม พ.ศ.2560] A. grunniens …

Effect Of Temperature On Antioxidant Enzyme Activities And Gene Expression In Sand Worm Perinereis Quatrefagesi (Grube, 1878), Sucharat Suksai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Polychaetes is one of intertidal animals that face the fluctuations of coastal environment through time. One of important environmental factors to animals is temperature regarding to the fluctuation of temperature in intertidal environment. Human activities could also cause high changes in water temperature by high temperature discharges from urban and industries. Since global warming is still a main issue, an increase of seawater temperature about 3°C could be possible as a prediction. This study aimed to investigate effect of temperature in polychaetes Perinereis quatrefagesi at cellular level, which could be indicated by heat shock response and oxidative stress due to …

นิเวศวิทยาการกินอาหารเชิงเปรียบเทียบระหว่างปลาแป้นจมูกสั้น Nuchequula Gerreoides (Bleeker, 1851) และปลาแป้นกระสวย Eubleekeria Splendens (Cuvier, 1829) จากปากแม่น้ำปราณบุรี ประเทศไทย, ทัศพร กาญจนเรขา

Chulalongkorn University Theses and Dissertations (Chula ETD)

Description of the resource partitioning (or niche differentiation) among fish is an essential part of substantial difference in a resources used for coexisting species for reducing competition. Food and reproductive activity are the most important factor concerning the resource partitioning among fishes. Decorated ponyfish (Nuchequula gerreoides) and splendid ponyfish (Eubleekeria splendens) are the two abundantly co-occurring leiognathid’s species in the Pranburi river estuary. The coexistence of these two species may promote resource partitioning. To examine this hypothesis, two important ponyfishes were collected from the Pranburi river estuary in this study. All fish specimens collection were carried out during dry (February …

บทบาทของสัตว์ทะเลหน้าดินขนาดใหญ่ในการเป็นแหล่งอาหารของนกชายเลนในนาเกลือที่ถูกทิ้งร้าง จังหวัดเพชรบุรี, ธนภัทร กลับชุ่ม

Chulalongkorn University Theses and Dissertations (Chula ETD)

นกชายเลนเป็นกลุ่มนกอพยพที่เข้ามาหากินในอ่าวไทยตอนในบริเวณหาดเลนและบางส่วนของนาเกลือ นาเกลือที่ถูกทิ้งร้างมีศักยภาพเป็นแหล่งหาอาหารของนกชายเลน เนื่องจากเป็นที่อาศัยของสัตว์ทะเลหน้าดินขนาดใหญ่ซึ่งเป็นอาหารหลักของนกชายเลนหลายชนิดในช่วงฤดูอพยพ งานวิจัยนี้มีวัตถุประสงค์เพื่อศึกษาความสัมพันธ์ระหว่างโครงสร้างชุมชนของของสัตว์ทะเลหน้าดินขนาดใหญ่ และความชุกชุมของนกชายเลนที่ลงเข้าใช้ในบ่อนาเกลือที่ถูกทิ้งร้างในตำบลปากทะเล อำเภอบ้านแหลม จังหวัดเพชรบุรี ในบ่อนาเกลือที่ถูกทิ้งร้างสองแบบ คือ บ่อที่ดินโผล่พ้นน้ำเมื่อน้ำลง (A) และบ่อที่ถูกน้ำท่วมตลอดเวลา (B) ทำการเก็บตัวอย่างดิน และเก็บข้อมูลของนกชายเลนในช่วงเวลาน้ำลงต่ำสุด เดือนละ 1 ครั้ง ตั้งแต่เดือนตุลาคม พ.ศ. 2560 - เดือนพฤษภาคม พ.ศ. 2561 ผลการศึกษาพบสัตว์ทะเลหน้าดินขนาดใหญ่ทั้งสิ้น 60 ชนิด กลุ่มที่มีความหนาแน่นสูงสุด คือ ไส้เดือนทะเลและแมลง ตามลำดับ โดยไส้เดือนทะเลมีความหนาแน่นสูงในบ่อที่ดินโผล่พ้นน้ำซึ่งมีความเค็มใกล้เคียงกับความเค็มของน้ำทะเล ส่วนบ่อที่ถูกน้ำท่วมตลอดเวลาที่มีลักษณะพื้นที่ที่แตกต่างกัน เช่น พื้นที่น้ำท่วมสูง และพื้นที่เนินดินที่ถูกปกคลุมด้วยไบโอฟิลม์ ซึ่งมีแมลงเป็นกลุ่มเด่น ส่วนนกชายเลนพบทั้งสิ้น 23 ชนิด รวม 7,715 ตัว ความชุกชุมของนกชายเลนสูงสุดในเดือนตุลาคมซึ่งเป็นช่วงต้นฤดูอพยพ รองลงมาในเดือนมกราคมเป็นฤดูอพยพ และในเดือนเมษายนเป็นช่วงปลายฤดูอพยพ ตามลำดับ การผันแปรชองชนิดและความหนาแน่นของสัตว์ทะเลหน้าดินขนาดใหญ่และนกชายเลนอยู่ภายใต้อิทธิพลของปัจจัยสิ่งแวดล้อมที่สำคัญ คือ ระดับน้ำในบ่อ ซึ่งในบ่อที่ถูกน้ำท่วมตลอดเวลามีน้ำลึกเฉลี่ย 10 เซนติเมตร ดินตะกอนในบ่อมีปริมาณอินทรีย์สารและปริมาณซัลไฟด์ทั้งหมดสูง ส่วนนกชนิดเด่นที่พบลงหากินในบ่อนี้ คือ นกปากแอ่นหางดำและนกตีนเทียน ซึ่งเป็นนกขนาดใหญ่ที่มีปากและขายาว โดยเฉพาะนกปากแอ่นหางดำเป็นนกที่มีสถานภาพใกล้ถูกคุกคามและมีความสัมพันธ์กับความหนาแน่นของแมลง ส่วนบ่อที่ดินโผล่พ้นน้ำมีน้ำตื้น (เฉลี่ย 3 เซนติเมตร) นกชนิดเด่นที่พบในบ่อนี้ คือ นกหัวโตทรายและนกชายเลนปากกว้างซึ่งเป็นนกขนาดเล็กและมีขาสั้น การศึกษาครั้งนี้แสดงให้เห็นถึงความสำคัญความอุดมสมบูรณ์ของสัตว์ทะเลหน้าดินรวมถึงสภาพแวดล้อมในนาเกลือที่ถูกทิ้งร้าง เช่น ความลึกของน้ำและความเค็มของน้ำในบ่อซึ่งใกล้เคียงกับสภาพของหาดเลนในธรรมชาติ ส่งผลให้บ่อนาเกลือร้างที่ศึกษามีความสำคัญทั้งในด้านของการเป็นแหล่งอาหารและหากินของนกชายเลน (ซึ่งรวมถึงนกที่มีสถานภาพการอนุรักษ์ถึง 7 ชนิด) นอกจากนี้นาเกลือที่ถูกทิ้งร้างเป็นแหล่งทำรังวางไข่ให้แก่นกประจำถิ่น