MEPS 347:261-274 (2007)  -  DOI:

Dispersal modeling of fish early life stages: sensitivity with application to Atlantic cod in the western Gulf of Maine

Martin Huret1,4,*, Jeffrey A. Runge2, Changsheng Chen1, Geoffrey Cowles1, Qichun Xu1, James M. Pringle3

1School of Marine Science and Technology, University of Massachusetts—Dartmouth, 706 South Rodney French Boulevard, New Bedford, Massachusetts 02744, USA
2Gulf of Maine Research Institute and School of Marine Sciences, University of Maine, 350 Commercial Street, Portland, Maine 04101, USA
3Coastal Observing Center and Ocean Process Analysis Laboratory, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, 142 Morse Hall, Durham, New Hampshire 03824, USA
4Present address: IFREMER. Département Ecologie et Modèles pour l’Halieutique, BP21105, 44311 Nantes Cedex 03, France

ABSTRACT: As an initial step in establishing mechanistic relationships between environmental variability and recruitment in Atlantic cod Gadhus morhua along the coast of the western Gulf of Maine, we assessed transport success of larvae from major spawning grounds to nursery areas with particle tracking using the unstructured grid model FVCOM (finite volume coastal ocean model). In coastal areas, dispersal of early planktonic life stages of fish and invertebrate species is highly dependent on the regional dynamics and its variability, which has to be captured by our models. With state-of-the-art forcing for the year 1995, we evaluate the sensitivity of particle dispersal to the timing and location of spawning, the spatial and temporal resolution of the model, and the vertical mixing scheme. A 3 d frequency for the release of particles is necessary to capture the effect of the circulation variability into an averaged dispersal pattern of the spawning season. The analysis of sensitivity to model setup showed that a higher resolution mesh, tidal forcing, and current variability do not change the general pattern of connectivity, but do tend to increase within-site retention. Our results indicate strong downstream connectivity among spawning grounds and higher chances for successful transport from spawning areas closer to the coast. The model run for January egg release indicates 1 to 19% within-spawning ground retention of initial particles, which may be sufficient to sustain local populations. A systematic sensitivity analysis still needs to be conducted to determine the minimum mesh and forcing resolution that adequately resolves the complex dynamics of the western Gulf of Maine. Other sources of variability, i.e. large-scale upstream forcing and the biological environment, also need to be considered in future studies of the interannual variability in transport and survival of the early life stages of cod.

KEY WORDS: Gulf of Maine · Atlantic cod · Gadhus morhua · Larval transport · Particle dispersal · Modeling sensitivity · Spawning grounds · Meso-scale processes and turbulence

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Cite this article as: Huret M, Runge JA, Chen C, Cowles G, Xu Q, Pringle JM (2007) Dispersal modeling of fish early life stages: sensitivity with application to Atlantic cod in the western Gulf of Maine. Mar Ecol Prog Ser 347:261-274.

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