The Baja California to Bering Sea (B2B) Marine Conservation Initiative seeks to establish a network of Marine Protected Areas within the Exclusive Economic Zones of the NAFTAcountries- Canada, Mexico, and the United States. This network is designed to capture ecologically significant habitat for marine species of common conservation concern and pelagic regions of high productivity, with due consideration for the inter-annual sea surface temperature fluctuations of the El Niño Southern Oscillation (ENSO). Here, we present analytical methods that define pelagic habitat based upon the density of steep temperature gradients, or fronts, and we quantify their spatial and temporal persistence over a single ENSO cycle (1996-1999) to benefit marine conservation and marine management strategies.

We find that less than 1% of the Northeast Pacific ocean exhibits a persistent ( > 8 mo/yr) concentration of temperature fronts (> .2km/km2) within and between years. The Baja California Frontal System (BCFS) is the largest concentration found within the multinational federal waters, between 0 and 300 km east of Baja California Sur. The BCFS appears more active under La Niña conditions, while the next largest persistent concentration, North Pacific Transition Zone, appears more active under El Niño conditions. We demonstrate habitat functions associated with the BCFS for blue whales (Balaenoptera musculus), swordfish (Xiphias gladius), and striped marlin (Tetrapturus audax). We recommend management and protection for this pelagic “hotspot” to the Mexican government and the tri-national Commission for Environmental Cooperation.

Etnoyer, P., D. Canny, B. Mate, and L. Morgan. 2004. Persistent pelagic habitats in the Baja California to Bering Sea (B2B) ecoregion. Oceanography 17(1):90–101, https://doi.org/10.5670/oceanog.2004.71.

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