Human activities are degrading the physical, chemical, and biological properties of the marine environment; causing the collapse of many fisheries worldwide (1). As a result, fishery managers and policy makers are being tasked with developing policies and management techniques that increase the sustainability of the global fishing industry.

Marine reserves (MR) are an emerging tool for protecting biodiversity, sustaining productivity, and allowing for continued extractive uses of the marine environment (1,2). Over the past decade, MRs have gained rhetorical acceptance in fishery management plans as a means of mitigating uncertainty and bet-hedging against management failure while promoting marine habitat protection (3,4). Yet despite their anticipated importance, MRs effectively protect less than 0.01% of the world’s oceans (3).

The design of MRs rests on two critical principles: 1) spillover (export of biomass via juvenile/adult emigration) from within a reserve into adjacent waters; and 2) population connectivity on a regional scale via pelagic egg/larval dispersal. Although there is evidence that MRs provide spillover effects (see 1,4,5); the degree to which population connectivity occurs is debatable (4), and due to a lack of connectivity-model validation and conflicting results from field trials using various stocks, much uncertainty remains (4,6,7). Many regard larval dispersal in marine ecosystems to be one of the “major unsolved problems of biological oceanography” (8). However, accurate and robust estimates of well- defined larval dispersal and well-defined local retention are essential prerequisites to resolving marine colonization patterns and to design effective marine reserves (9).

I propose to quantify the extent of larval dispersal and subsequent benthic recruitment in the Strait of Georgia and then develop a spatially-explicit population model that has sufficient predictive capability to increase the effectiveness of marine reserve designs, from a connectivity perspective.

To track larval dispersal, two complementary fish otolith tagging techniques will be used; one natural and one artificial. The first relies on the fact geochemical signatures of population origin reside in the calcified structures of fish larvae (i.e. otoliths) and act as a natural tag (9). Mass spectrometry (i.e. ICP-MS) will be used to identify trace element signatures within the otolith created by spatial differences in water chemistry (typical of coastal systems in which this study will occur; 9,10,11). These natural tag data, from a larger spatial and temporal scale, will be validated through an independent mark-recapture study on a subset of individuals from known source locations. In this second study, an artificial fluorescent compound (i.e. oxytetracycline) will be used to tag the eggs of the model fish species (cabezon, Scorpaenichthys marmoratus and garibaldi, Hypsypops rubicundus). This compound creates an unambiguous fluorescence signature during UV microscopy, is readily incorporated into the calcified tissues of larvae, and has been successfully used to mass-mark batches of fish eggs in the field (9,12). Furthermore, research shows these tags are detectable for up to 3 years, exposure does not impact larval growth or mortality, and a 100% marking efficiency is possible over a range of immersion times and chemical concentrations; making this technique ideally suited for the study in question.(9).

This project will yield the first unequivocal data set that realistically describes larval dispersal on a regional scale. The findings will be used to create an explicit population connectivity model that will be invaluable to scientists, resource managers, and policy makers involved in the planning process of marine reserve networks; and will act to construct the blueprint for future marine reserves, increasing the sustainability of marine fisheries while simultaneously protecting marine biodiversity.