Observations on the Life History of the Barndoor Skate, Dipturus laevis, on Georges Bank (Western North Atlantic)

Todd Gedamke, William D. DuPaul and John A. Musick

Virginia Institute of Marine Science, College of William and Mary
P.O. Box 1346, Rt. 1208 Greate Rd., Gloucester Point, VA, 23062, USA

Publication (Upload) date: 10 January 2005

GEDAMKE, T., W. D. DUPAUL, and J. A. MUSICK. 2005. Observations on the Life History of the Barndoor Skate, Dipturus laevis, on Georges Bank (Western North Atlantic). J. Northw. Atl. Fish. Sci., 35: 67-78. https://doi.org/10.2960/J.v35.m512

Abstract

The barndoor skate (Dipturus laevis) has been reported to be close to extinction in parts of its northern range and is believed to be particularly vulnerable to fishing mortality due to its relatively large size. A lack of basic life history information, however, has hampered an accurate assessment and management of north Atlantic populations. In an attempt to fill this void, information was collected from 2 310 specimens caught during commercial sea scallop dredging in the southern section of Georges Bank Closed Area II. Eighty-seven fish were determined to be mature from a visual inspection of reproductive tracts and the allometric growth of claspers, oviducal glands and developing ova. Sexual dimorphism was apparent in length at 50% maturity with females maturing at 116.3 cm and males at 107.9 cm. A preliminary analysis of 118 vertebrae indicates faster growth (k = 0.14 to 0.18) and younger female maturation (6.5 to 7.2 yr) than previously believed. Thus, resilience of the barndoor skate to overfishing may be higher than recently assumed.

Key words: Dipturus laevis, Georges Bank, growth, life history, maturity, reproduction, skate

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