Spawning habitat of the Atlantic menhaden in Onslow Bay, North Carolina |
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| Authors: | Checkley Jr Ortner Werner Settle & Cummings |
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| Institution: | Marine Life Research Group, Scripps Institution of Oceanography, La Jolla, CA 92093-0218, USA; Atlantic Oceanographic and Meteorological Laboratory, NOAA, Miami, FL 33176, USA; Department of Marine Sciences, CB# 3300, University of North Carolina, Chapel Hill, NC 27599-3300, USA; Beaufort Laboratory, National Marine Fisheries Service, NOAA, Beaufort, NC 28516-9722, USA |
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| Abstract: | The Continuous, Underway Fish Egg Sampler (CUFES) was used to sample pelagic eggs of the Atlantic menhaden ( Brevoortia tyrannus ) from 3-m depth off North Carolina in winter 1993–94 and 1994–95. Simultaneous measurements were made of temperature, salinity, and the concentration of chlorophyll a . The maximal concentration of eggs was 346 eggs m−3. Eggs were highly aggregated in patches which occurred between the Gulf Stream and mid-shelf fronts (17–23°C, 36.0–36.4‰). Unexpectedly, eggs were found almost exclusively in water of 20–60 m (mode 20 m) bottom depth. Thus, spawning appears related to bathymetry as well as hydrography. Variograms for egg concentration indicated a mean (± SE) patch scale of 3.6 ± 1.7 km and a high degree of spatial variance explained by CUFES sampling. Lagrangian modelling of particles moving in response to tides, winds, and a prescribed flow from the north indicated that the region of observed, maximal occurrence of eggs is favourable for the retention of eggs and larvae on the shelf adjacent to inlets used to enter nursery areas. |
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| Keywords: | spawning pelagic fish eggs Atlantic menhaden Brevoortia tyrannus Gulf Stream model transport recruitment sampling variogram CUFES SABRE |
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