The Midriff Islands- Isla Partida Norte and Isla Rasa
This glorious day, bracketed by sightings of lunging fin whales at sunrise and again at sunset, delighted our senses with a remarkable array of sea creatures and seabirds under, on and above the water. Ocean productivity is very high here and evident in the abundance of marine mammals and large seabird populations. Tidal rips and geologic constrictions cause swift currents to sweep through this region of the northern Sea of Cortez, causing cold nutrient rich water from the sea bottom to mix into the upper water layers and create an ideal habitat for phytoplankton, zooplankton and small schooling fishes like sardines and anchovies. Those two important species support the local cetaceans and thousands of breeding seabirds.
Early this morning, large groups of blue-footed boobies swooped over our Zodiacs and headed out to sea as we cruised around Isla Partida Norte and talked about the wonders of the resident fish-eating bats as well as the least and black petrels that nest among the rocks of this interesting bit of recently (in geologic time) extruded basalt. A pre-lunch snorkel turned up two octopus and lots of stingrays as well as beautiful red barrel and sulfur sponges.
On foot and in small boats we turned our attention to amazing little Rasa Island this afternoon. Though many of their parents have moved on, thousands of Heerman’s gull and elegant and royal tern chicks remain and are acquiring their flight feathers and learning to catch fish; the photo shows a few of them at work. Their numbers attest to the health and abundance of the web of life here in this extraordinary small place.
This glorious day, bracketed by sightings of lunging fin whales at sunrise and again at sunset, delighted our senses with a remarkable array of sea creatures and seabirds under, on and above the water. Ocean productivity is very high here and evident in the abundance of marine mammals and large seabird populations. Tidal rips and geologic constrictions cause swift currents to sweep through this region of the northern Sea of Cortez, causing cold nutrient rich water from the sea bottom to mix into the upper water layers and create an ideal habitat for phytoplankton, zooplankton and small schooling fishes like sardines and anchovies. Those two important species support the local cetaceans and thousands of breeding seabirds.
Early this morning, large groups of blue-footed boobies swooped over our Zodiacs and headed out to sea as we cruised around Isla Partida Norte and talked about the wonders of the resident fish-eating bats as well as the least and black petrels that nest among the rocks of this interesting bit of recently (in geologic time) extruded basalt. A pre-lunch snorkel turned up two octopus and lots of stingrays as well as beautiful red barrel and sulfur sponges.
On foot and in small boats we turned our attention to amazing little Rasa Island this afternoon. Though many of their parents have moved on, thousands of Heerman’s gull and elegant and royal tern chicks remain and are acquiring their flight feathers and learning to catch fish; the photo shows a few of them at work. Their numbers attest to the health and abundance of the web of life here in this extraordinary small place.
