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Quantifying Larval Dispersal and Local Retention within a Marine Reserve Network of the Southern California BightEPA Grant Number: F6E20306
Title: Quantifying Larval Dispersal and Local Retention within a Marine Reserve Network of the Southern California Bight
Investigators: Cook, Geoffrey
Institution: Scripps Institution of Oceanography
EPA Project Officer: Jones, Brandon
Project Period: September 1, 2006 through September 1, 2009
Project Amount: $107,682
RFA: STAR Graduate Fellowships (2006) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Aquatic Ecosystems , Biology/Life Sciences , Fellowship - Biological Oceanography
Marine protected areas (MPA) are an emerging tool for protecting biodiversity and allowing for continued extractive uses of the marine environment. Marine reserves (MR; also known as no-take reserves) are the most restrictive form of MPA. The design of MRs rests on two principles: 1) spillover of biomass from within a reserve into adjacent waters; and 2) metapopulation connectivity via larval dispersal. Due to a lack of model validation and conflicting results from field trials, much uncertainty remains regarding the extent of population connectivity via larval dispersal. Many regard larval dispersal as a “major unsolved problem” (Palumbi 1999), and one of the “crucial gaps in scientific knowledge” facing marine ecologists, resource managers, and policymakers (Sale et al. 2005). Accurate estimates of larval dispersal and local retention are essential prerequisites to designing effective MRs. This project will quantify local retention and population connectivity via larval dispersal of three fishes, garibaldi (Hypsypops rubicundus), blacksmith (Chromis punctipinnis), and cabezon (Scorpaenichthys marmoratus) within an MR network of southern California.
These data will be the first to quantify population connectivity via larval dispersal along an open coastline and will help construct a metapopulation connectivity model that will act as a blueprint for the design of future marine reserve networks, moving marine fisheries closer to sustainability while simultaneously protecting marine biodiversity for future generations.
To track larval dispersal, two complementary tagging techniques will be used. The first relies on the fact geochemical signatures of population origin reside in the otoliths of fish larvae, acting as a natural tag. Mass spectrometry (LA-ICPMS) will be used to identify trace element signatures in fish otoliths created by spatial differences in water chemistry. These data will be validated through a mark-recapture study on individuals from known source locations. In this second study, artificial fluorescent compounds (e.g. tetracycline) will be used to tag the eggs of the model fish species, yielding an unequivocal description of natal origin.
The findings of this project will enable a quantitative analysis of the design of marine reserves, and will prove invaluable to policy makers and resource managers involved in the planning process, implementation, and subsequent monitoring of marine reserve networks. This project will provide a method for determining if larval connectivity is occurring and for quantifying the magnitude of such connectivity. These techniques will then be available for use with more commercially important species inhabiting coastal waters, bettering our ability to effectively manage marine populations.