Rational design of Marine Protected Areas in the San Juan Islands


Conservation issues, especially those connected with marine and freshwater ecosystems, are at a critical point in the Northwest. The decisions, or lack of decisions, that we make in the next decade will likely have consequences for marine populations and the ecosystems that surround us for centuries to come. Terrie Klinger, Alan Trimble, and I, together with other collaborators, have begun a long-term program to rationally design marine reserves in the San Juan Island archipelago. This program combines larval invertebrate and fish behavioral modeling with benthic ecology and physical oceanography, into a comprehensive modeling framework. The framework's purpose is to provide as sound a basis as possible, based on present knowledge, for assessing which areas or sets of areas best contribute to persistence and stability of marine populations in the San Juans.


Our approach is to estimate degrees of connectivity – one- and two-way transport of dispersing larvae between habitats – in a variety of potential marine reserve regimes. We believe that this project will accomplish three worthwhile objectives: First, we will be able to supply a scientific basis for advocating some reserve designs over others. Second, our project will be a ``case study'' that helps to set a new standard for thorough, detailed application of ocean sciences to applied conservation questions. Third, our work will be important from a basic ecology perspective, because it will show us whether a knowledge of general habitat type and and transport processes is sufficient to predict distributions and abundances of benthic species.

 

The Marine Reserve Design project has several elements. Two components are aimed at estimating dispersal patterns for planktonic larval stages of important benthic vertebrate and invertebrate species:

• A drift card study, led by Terrie Klinger, quantifying the transport of Lagrangian surface drifters in the San Juans.

• Computer simulations of Lagrangian drifters through the San Juan region.

A sample drift card.

Drift card recoveries for Release Site R (Pt. Caution, near Friday Harbor Labs, San Juan Islands, WA) in a study by Terrie Klinger.

Two other components are aimed at characterizing the distribution and abundance of benthic adults (Terrie Klinger), together with mapping the distribution of suitable habitatthrough fine-scale bathymetry(Gary Greene, Moss Landing).

Two additional components quantify the individual-level behavior of dispersing larvae, and integrate this behavior into large-scale circulation models (more details).

In the long term, we plan to combine these studies with ship-board surveys, remote sensing from buoys and satellites. Direct observation and modeling of circulation will provide estimates of physical transport of organisms between various parts of the San Juan region and between the San Juans and adjacent regions.

Lagrangian drifter trajectories in a computer simulation of tidal flows in the San Juan Channel. The release site corresponds to Release Site R in Terrie Klinger's drift card study.

Lagrangian drifter trajectories in a computer simulation by Alan Trimble. showing routes taken by drifters released from a number of sites throughout the San Juan Islands, correspond to release sites in Terrie Klinger's drift card study.

 

 

 

An example of fine-scale bathymetry by Gary Greene of Moss Landing. This graphic shows the bottom topography of Cattle Pass, between San Juan and Lopez Islands.

 

 

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