The commercially and recreationally important winter flounder (Pseudopleuronectes americanus) is commonly found from Labrador to Georgia, but is most abundant in the Gulf of Maine. Like most groundfish species off the coast of New Hampshire catches have steadily declined over the past 25 years. Winter flounder are capable of releasing hundreds of thousands of eggs annually but because of the vulnerability of the small, early life-history stages, there is high natural mortality, and few survive to maturity. By captively spawning, rearing, and releasing animals at a size or age beyond this mortality window natural stocks may be enhanced. The purpose of stock enhancement is to help conserve, manage and restore natural fish populations.

A major challenge of any captive rearing program, whether for aquaculture or stock enhancement, is providing the appropriate diet regimes during development. Typically marine fish larvae are initially fed live food (e.g. rotifers, Artemia), and are then weaned onto formulated diets as they attain a size or developmental state that supports consumption of formulated diets. Weaning onto formulated diets is a stressful time for cultured fish, and this is especially true for flatfish that are concurrently undergoing dramatic morphological and physiological transformations associated with metamorphosis. Weaning occurs twice for fish that are used for stock enhancement; the second time occurs as they transition from formulated hatchery feed back onto live diets once released. Fish may take 3-4 days before they begin feeding on live prey, and even then, non-traditional food sources may be selected due to size/shape resemblances to formulated laboratory diets.This short period of starvation during the second transition can also alter feeding behavior, which may result in increased predation risk for reared fish. To successfully wean fish for stock enhancement during these sensitive early life stages, we need to fully understand the ontogenetic development of the digestive system. We also need to identify diets that will optimize weaning success in the laboratory and minimize the effects of subsequent weaning in the wild. Finally, we need to examine the transition onto natural diets once reared individuals are released and investigate dietary differences between recently released and wild stocks.

The overall objective of this dissertation is to describe the ontogenetic development of the digestive system in winter flounder, and to identify weaning strategies that maximize survival, growth, and condition after their release into nature. Specific objectives include:

• (1) DESCRIBING DEVELOPMENT OF THE DIGESTIVE TRACT: describe the morphological changes of the digestive system and its associated structures from hatching through the post-metamorphic juvenile period in both reared and wild individuals and depict the biochemical changes associated with development of the digestive tract including changes in intensity and locality of enzyme activity


• (2) QUANTIFYING WEANING SUCCESS: determine how different diets (both live and formulated) influence weaning success in the laboratory as indicated by instantaneous growth rate, gut fullness, survival, and condition and examine how this success translates to successful weaning of individuals onto wild prey once released into nature


• (3) EXAMINING FEEDING BEHAVIOR: compare the behavior of reared and wild individuals by quantifying feeding activities and by examining the influence of prey shape and movement

• Walsh, M.L. and Howell, W.H. Winter flounder movements off of Southern New Hampshire. The Second International Symposium on Tagging and Tracking Marine Fish with Electronic Devices. San Sebastian, Spain. 8-11 October 2007.
  
  
• Walsh, M.L. and Howell, W.H. Winter flounder movements off of Southern New Hampshire. Flatfish Biology Conference. Milford, CT. 29-30 November 2006.
  
  
• Walsh, M.L. Individual variability in consumption rates of juvenile winter flounder, Pseudopleuronectes americanus. UNH Graduate Research Conference, Durham, NH. 19 April 2007.
  
  
• Walsh, M.L. Individual variability in consumption rates of juvenile winter flounder, Pseudopleuronectes americanus. Larval Fish Conference, American Fisheries Society Annual Meeting. Lake Placid, NY. 10-14 September 2006.
  
  
• Walsh, M., D.A. Witting, and R.C. Chambers. The role of individual variability on consumption rates and growth of captive juvenile winter flounder, Pseudopleuronectes americanus. Annual Meeting of the American Society of Ichthyologists and Herptologists, New Orleans, LA. 12-17 July 2006.
  
  
• Walsh, M., D.A. Witting, and R.C. Chambers. The role of intra- and inter-individual variability on consumption rates of recently metamorphosed winter flounder, Pseudopleuronectes americanus. Flatfish Biology Conference. Mystic, CT. 1-2 December 1998.
  
  
• Walsh, M.L. Ingested versus assimilated diet of the Rabbitfish, Siganus fuscescens, in Moreton Bay, Southeast Queensland, Australia. Henry Rutgers Scholars Thesis. New Brunswick, NJ. January 1998.
  

• Masters in Education. St. Peter's College. Jersey City, NJ Jan '99 - Aug '00 GPA: 3.96/4.0
  
• New Jersey State Secondary Teacher’s Certification
• U.S. National Teacher's Examination (1997) Biology Content and General Science Content Knowledge.
• Watchung Hills Board of Education (2000-2002) Warren, NJ
  Secondary teacher of biology (9th and 10th graders) and ecology (11th and 12th graders). Constructed the ecology class curriculum and proficiencies at this nationally acclaimed Blue Ribbon School.
• Estelle Finkel Educational Consultants - Livingston, NJ 
  Taught and constructed science curriculums for advanced elementary students. Classes included "The Anatomy of the Fetal Pig" (4th-5th graders), "Marine Biology" (1st-3rd graders), and "Sharks and the Environment" (1st-3rd graders) at the Gifted and Talented Institute.
• School of Ecology & Environment, Deakin University (2003) Warrnambool, VIC, Australia
  Field assistant and guest lecturer for a Marine Ecology field course at Deakin University in Warrnambool. Acted as a team advisor helping senior level university students formulate projects, test hypotheses, and develop models.
  
• College Teaching assistantships:
• General Ecology (BIO 541) Fall '06. Writing and field intensive. Physical and biological factors affecting distribution, abundance and adaptations of organisms. Population, community, and ecosystem structure and function.
• Ichthyology (ZOOL 710) Fall '07.
Field intensive. Introduces the evolution, systematics, anatomy, physiology, and ecology of fishes, with emphasis on New England species.
• Animal Behavior (ZOOL 713) Fall '07. Writing intensive. Introduces the naturalistic study of animal behavior. Emphasizes the evolution, development, physiology, and ecology of behavior. Topics include the genetic and acquired bases of behavior, neuroethology and behavioral endocrinology, communication, orientation, foraging strategies, reproductive ecology, and the evolution of altruistic behavior.