Caribbean Dispersal Patterns Vary with Larval Fish Behavior, Hydrography, and Habitat Availability

Christina Hernandez1, Claire B B Paris2, Ana Carolina Vaz2, Benjamin Jones3, Julie Kellner4, David Richardson5, Robert Cowen6, Su Sponaugle7 and Joel Llopiz8, (1)Woods Hole Oceanographic Institution, Woods Hole, MA, United States, (2)University of Miami, Miami, FL, United States, (3)MIT-WHOI Joint Program, Biological Oceanography, Woods Hole, MA, United States, (4)International Council for the Exploration of the Seas (ICES), Copenhagen, Denmark, (5)NOAA Northeast Fisheries Science Center, Narragansett, RI, United States, (6)Oregon State University, Hatfield Marine Science Center, Newport, OR, United States, (7)Oregon State University, Department of Integrative Biology, Corvallis, OR, United States, (8)Woods Hole Oceanographic Institution, Woods Hole, United States
Abstract:
Biophysical particle-tracking modeling, when combined with field data on biological and behavioral traits of larval reef fish, provides valuable insight into how different processes create patterns of dispersal distances and connectivity. In this study, we investigated how larval behavior and traits—specifically depth preferences and pelagic larval duration (PLD)—influence dispersal and connectivity across the Caribbean as well as regionally. We used a large data set on larval fish collected via multiple opening-closing (MOCNESS) nets in the Straits of Florida to parameterize a biophysical model, the Connectivity Modeling System (CMS). Informed by the field-derived vertical distribution data, we simulated three larval depth behavior scenarios: (1) surface-dwelling, (2) evenly distributed in upper 100 m, and (3) ontogenetic vertical migration (OVM). Using global and Gulf of Mexico HYCOM hydrodynamic data from 2005-2008, virtual larvae were released nightly from 259 reef habitat polygons covering all major regions of the Caribbean. We selected two PLD lengths corresponding to well-studied larval fish that exhibit OVM behavior: 20-32 days for the bicolor damselfish (Stegastes partitus) and 42-54 days for the bluehead wrasse (Thalassoma bifasciatum). Median dispersal distance under the long PLD simulations was approximately twice as far as under the short PLD simulations, for all depth behaviors. An even vertical distribution led to the shortest dispersal distances, and therefore the greatest level of local retention. The surface-associated behavior had the greatest dispersal distances, and the OVM behavior was intermediate in terms of dispersal distance. However, when the results are analyzed on a regional basis (e.g., Florida Keys, Leeward Islands, Jamaica, etc.), there was notable variation in which behavior leads to the greatest local retention. As such, we find that the optimal vertical distribution behavior for local retention is dependent on local hydrography and the downstream distribution of settlement habitat.
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