title: Goosefish Lophius americanus fecundity and spawning frequency, with implications for population reproductive potential.
abstract: To improve knowledge of goosefish Lophius americanus' reproductive biology, females were collected during 2009-2012 from the Mid-Atlantic Bight shelf region of the U.S. east coast. Batch fecundity increased with total length (LT), from 229 100 to 2 243 300 mature oocytes per female (LTrange: 55·5-112 cm; n = 54). This estimate of fecundity at LTis lower than one derived from a sample collected during 1982-1985. Examination of whole oocyte diameters in different months indicated that L. americanus is a serial spawner, releasing more than one egg veil per spawning season, as suspected or observed for other Lophius species. Seasonality of spawning was evident from whole oocytes and gonad histology, and from larval fish surveys spanning the U.S. north-east shelf, and confirmed a protracted (c. 6 months) spawning period. Peak spawning activity progressed northward from spring to autumn. The population-level implications of these results were explored by estimating population reproductive potential (PRP), which considered the value of both current and future per capita reproduction using decade-specific age structure and fecundity at length. PRPis now more than 50% lower compared with the historical period (1982-1985), a result of the lower proportions of large females and reduced fecundity across all sizes. Mechanisms that could explain this loss of stock productivity are fishing-induced size-age truncation or regime shifts in egg production caused by changes in energy density of common forage species.
authors.affiliation: National Marine Fisheries Service, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA 02543, U.S.A.
authors.forename: R S
authors.initials: RS
authors.lastname: McBride
authors.affiliation: Living Marine Resources Cooperative Science Center, Department of Natural Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, U.S.A.
authors.forename: A K
authors.initials: AK
authors.lastname: Johnson
authors.affiliation: Living Marine Resources Cooperative Science Center, Department of Natural Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, U.S.A.
authors.forename: E K
authors.initials: EK
authors.lastname: Lindsay
authors.affiliation: National Marine Fisheries Service, Northeast Fisheries Science Center, Oceanography Branch, Narragansett, RI 02882, U.S.A.
authors.forename: H J
authors.initials: HJ
authors.lastname: Walsh
authors.affiliation: National Marine Fisheries Service, Northeast Fisheries Science Center, 166 Water Street, Woods Hole, MA 02543, U.S.A.
authors.forename: R A
authors.initials: RA
authors.lastname: Richards
mesh_terms: D000818:Animals; D005260:Female; D005298:Fertility / Q000502:physiology*; D005399:Fishes / Q000502:physiology*; D008297:Male; D011157:Population Dynamics; D012098:Reproduction / Q000502:physiology*
keywords: batch spawning; ichthyoplankton; monkfish; oogenesis; reproduction; reproductive value