Age, Growth and Reproduction in Atlantic Hagfish

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Project Type: 
Research
Project Number: 
R/FMD-168
Inception Date: 
2002
Completion Date: 
2003
Theme Area: 
Fisheries Resources

Participants:

Stacia Sower UNH - Department of Molecular, Cellular & Biomedical Sciences Principal Investigator
Mickie Powell UNH - Department of Molecular, Cellular & Biomedical Sciences Postdoctoral Student/Researcher

Students Involved:

Scott Kavanaugh UNH - Department of Molecular, Cellular & Biomedical Sciences
Joanne Davis UNH - Department of Biological Sciences
Samantha Meservey UNH - Department of Biological Sciences
Amy Agulay University of New Hampshire
Jennifer Wishinski UNH - Department of Biological Sciences
Lyn MacNevin UNH - Department of Biological Sciences
Taylor Heyl UNH - Department of Biological Sciences
Adam Baukus UNH - Department of Biological Sciences
Emily Violette University of New Hampshire
Jocelyn Sanford University of New Hampshire
Byron Pedler University of New Hampshire
Jen Gleico University of New Hampshire
Abstract: 

In response to a major decline or collapse of the fisheries (groundfish and anadromous species) industry in the Northeast, other species that were once considered alternative or underutilized species have and are being identified that may be suitable for commercial harvest. One such example is the hagfish.

An East Coast fishery for Atlantic hagfish, Myxine glutinosa, started in 1992. The landings for hagfish off the coast of Maine and Massachusetts have ranged from one to three million pounds each year during 1996-1999. However, there is little known about reproduction and the reproductive success in hagfish.

Currently, there are no regulations governing the harvesting of hagfish on the East Coast. Since there is little or no information on age determination, age and time of reproduction, seasonality of reproduction and growth of Atlantic hagfish, the level at which a sustainable fisheries for this species can be maintained is unknown. In order for fisheries management to manage its hagfish stocks and develop a sustainable commercial hagfish fishery, an information base is needed for optimum use of the hagfish resource.

Recent studies on estimates of population density of Atlantic hagfish indicate that hagfish populations are high in certain areas in the Gulf of Maine. However, a decline in abundance and a decrease in catch per unit effort with intense fishing activity has been reported for Pacific hagfish (eptatretids) off the coast of California and for Atlantic hagfish within the Gulf of Maine. Thus, there is an urgent need for basic research on the reproductive biology and ecology of hagfish.

To develop the scientific basis for a sound management plan, the main goal of this two-year project is to further our understanding of the growth and reproduction of Atlantic hagfish by testing the hypothesis that Atlantic hagfish exhibit seasonal reproductive growth. The specific objectives of the proposed research are to determine the size of onset of reproductive maturity, rate of reproduction, reproductive fecundity, and age and growth in Atlantic hagfish. In addition, we will investigate the seasonal relationships between changes in hypothalamic gonadotropin-releasing hormone and activity of the gonad. This information is critical to prevent the exploitation of the Atlantic hagfish off the New England coastline.

Objectives: 

To develop the scientific basis for a sound management plan, the main goal of this two-year project is to further our understanding of the growth and reproduction of Atlantic hagfish.

The specific objectives of the proposed research are to determine the size of onset of reproductive maturity, rate of reproduction, reproductive fecundity, and age and growth in Atlantic hagfish. In addition, we will investigate the seasonal relationships between changes in hypothalamic gonadotropin-releasing hormone and activity of the gonad.

Methodology: 

Once a month for 18 months, 200-300 hagfish will be caught off the New England coast. Total length, body weight, egg size and gonadal weight of hagfish will be recorded. Forty hagfish will be subsampled for brains and gonads. Gonads will be prepared for histological evaluation.

The information obtained from the histology, gonadosomatic index, length and weight will be used to assess the stage of sexual maturity and relative growth. Brains will be assayed for irGnRH to characterize seasonal relationships between activity of the gonad and brain GnRH. In addition, relative growth rates will be assessed from a subpopulation of hagfish maintained in specialized traps in the ocean.

Rationale: 

Currently, there are no regulations governing the harvesting of hagfish on the East Coast. A decline in abundance and a decrease in catch per unit effort with intense fishing activity has been reported for Pacific hagfish (eptatretids) off the coast of California and for Atlantic hagfish within the Gulf of Maine. Since there is little or no information on age determination, age and time of reproduction, seasonality of reproduction and growth of Atlantic hagfish, the level at which a sustainable fisheries for this species can be maintained is unknown. In order for fisheries management to manage its hagfish stocks and develop a sustainable commercial hagfish fishery, an information base is needed for optimum use of the hagfish resource.

Publications

Available from the National Sea Grant Library (use NHU number to search) or NH Sea Grant

Journal Article

  • Powell, M., S. Kavanaugh and S. Sower (2004). Seasonal concentrations of reproductive steriods in the gonads of the Atlantic hagfish, "Myxine glutinosa." Journal of Experimental Zoology 301 A:352-360.
  • Kavanaugh, S., M. Powell and S. Sower (2005). Seasonal changes of gonadotropin-releasing hormone in the Atlantic hagfish "Myxine glutinosa." General and Comparative Endocrinology 140(2):136-143.
  • Powell, M., S. Kavanaugh and S. Sower (2005). Current knowledge of hagfish reproduction: implications for fisheries management. Integrative and Comparative Biology 45(1):158-165.
  • Powell, M., S. Kavanaugh and S. Sower (2006). Identification of a functional corpus luteum in the Atlantic hagfish, "Myxine glutinosa." General and Comparative Endocrinology 148(1):95-101, August 2006.
  • Nozaki, M., Y. Oshima, T. Shimotani and S. Sower (2003). Immunohistochemical detection of gonadotropin-like material in the hagfish pituitary, correlated with their gonadal conditions. Fish Physiology and Biochemistry 28:85-87, 2003.

Report

  • Sexuality and embryogenesis of the Atlantic hagfish, "Myxine glutinosa": S.E.A.H. (2001). Joanne Davis, Samantha Meservey, Amy Agulay, Jennifer Wishinski and Lyn MacNevin. Advisors: Mickie Powell and Stacia Sower.

Thesis/Dissertation

  • Kavanaugh, S. (2004). Gonadotropin releasing hormone (GnRH) in chordates: the cloning of the GnRH precursor and the distribution of GnRH in the tunicate "Ciona intestinalis" and seasonal changes of GnRH in the Atlantic hagfish "Myxine glutinosa." Master's Thesis, University of New Hampshire.

Book Chapter

  • Sower, S., M. Powell and S. Kavanaugh (2004). Myxiniformes (Hagfishes). Gryzimek's Animal Life Encyclopedia 4 (Fishes I):77-81.

Proceeding

  • Watson, W. (1999). Lobster trapability and saturation study. U.S./Canadian Lobster Summit III Lobster Stock Assessment: Towards Greater Understanding, Collaboration and Improvement, Patrice Farrey, Marjorie Mooney-Seus and Heather Tausig, eds., pp. 48-55, Rockland, Maine, March 3-4, 1999.