Gulf of California Marine Sanctuary & Isla Santa Catalina
As Herman Melville noted in Moby Dick, the sperm whale is the most mysterious of all the great whales, because it dives extremely deep and its behaviors are largely hidden from observers on the deck of a vessel. Today started off with a sperm whale sighting off Isla Carmen just after breakfast, and, true-to-form, the cachalote soon disappeared, not to be seen again. But we were almost immediately treated to a pod of leaping bottlenose dolphins and several blue whales. The towering, long-lasting spouts of the blues were visible from afar, and when viewed close-up, the immense creatures glided smoothly and endlessly at the surface until finally showing their flukes and sounding.
We then headed for the most offshore island in the area, Isla Santa Catalina. Halfway there we paused to carry out oceanographic measurements using a recording profiler that logs depth, temperature, salinity, and concentrations of chlorophyll and oxygen. These measurements were the first to be taken in conjunction with a research project funded by National Geographic and organized by Professor William Gilly of Stanford University’s Hopkins Marine Station in California. It will form the baseline for a program of monitoring changes in important features of the water column and will provide insight into connections between the ocean’s surface and its midwater depths. In reality, these two regions are physically different bodies of water connected by a variety of living organisms ranging from microbes to the great whales.
Recent research has revealed an ongoing vertical expansion of a naturally occurring, midwater zone of low oxygen in productive regions of the world’s oceans, including the Sea of Cortez. A so-called Oxygen Minimum Zone (OMZ) is slowly moving upwards in the water column towards the surface. While we do not yet fully understand the reasons for this change, it seems clear that decreasing oxygen will impact the ecology of marine communities in profound and unpredictable ways. For example, Humboldt squid tolerate low oxygen and can feed in the OMZ, and expansion of this feature may be related to the relatively recent increase in their abundance. For the next two years Gilly’s project will monitor oxygen and other properties to depths of 2000 feet in the Sea of Cortez using the Lindblad vessels National Geographic Sea Lion and National Geographic Sea Bird. Success in this program will pave the way to long-term monitoring that will permit discerning changes in midwater oxygen and assessing long-term ecological impacts. Today’s deployment of the profiler was a total success, so a first big step has been taken.
We finished up the day with an afternoon of snorkeling and hiking at the remote Isla Santa Catalina. Snorkelers viewed many fishes, including spectacular king angelfish, superbly camouflaged giant hawkfish, and the diminutive, electric-blue Sea of Cortez damselfish. We also saw lobsters tucked in crevices, large gorgonian sea-fans and a multitude of other invertebrates. Hikers on shore saw the island in a rare burst of green after hurricane rains in the fall with hummingbirds visiting blossoms and doves sweetly calling in the sunset.
As Herman Melville noted in Moby Dick, the sperm whale is the most mysterious of all the great whales, because it dives extremely deep and its behaviors are largely hidden from observers on the deck of a vessel. Today started off with a sperm whale sighting off Isla Carmen just after breakfast, and, true-to-form, the cachalote soon disappeared, not to be seen again. But we were almost immediately treated to a pod of leaping bottlenose dolphins and several blue whales. The towering, long-lasting spouts of the blues were visible from afar, and when viewed close-up, the immense creatures glided smoothly and endlessly at the surface until finally showing their flukes and sounding.
We then headed for the most offshore island in the area, Isla Santa Catalina. Halfway there we paused to carry out oceanographic measurements using a recording profiler that logs depth, temperature, salinity, and concentrations of chlorophyll and oxygen. These measurements were the first to be taken in conjunction with a research project funded by National Geographic and organized by Professor William Gilly of Stanford University’s Hopkins Marine Station in California. It will form the baseline for a program of monitoring changes in important features of the water column and will provide insight into connections between the ocean’s surface and its midwater depths. In reality, these two regions are physically different bodies of water connected by a variety of living organisms ranging from microbes to the great whales.
Recent research has revealed an ongoing vertical expansion of a naturally occurring, midwater zone of low oxygen in productive regions of the world’s oceans, including the Sea of Cortez. A so-called Oxygen Minimum Zone (OMZ) is slowly moving upwards in the water column towards the surface. While we do not yet fully understand the reasons for this change, it seems clear that decreasing oxygen will impact the ecology of marine communities in profound and unpredictable ways. For example, Humboldt squid tolerate low oxygen and can feed in the OMZ, and expansion of this feature may be related to the relatively recent increase in their abundance. For the next two years Gilly’s project will monitor oxygen and other properties to depths of 2000 feet in the Sea of Cortez using the Lindblad vessels National Geographic Sea Lion and National Geographic Sea Bird. Success in this program will pave the way to long-term monitoring that will permit discerning changes in midwater oxygen and assessing long-term ecological impacts. Today’s deployment of the profiler was a total success, so a first big step has been taken.
We finished up the day with an afternoon of snorkeling and hiking at the remote Isla Santa Catalina. Snorkelers viewed many fishes, including spectacular king angelfish, superbly camouflaged giant hawkfish, and the diminutive, electric-blue Sea of Cortez damselfish. We also saw lobsters tucked in crevices, large gorgonian sea-fans and a multitude of other invertebrates. Hikers on shore saw the island in a rare burst of green after hurricane rains in the fall with hummingbirds visiting blossoms and doves sweetly calling in the sunset.
