Sunny, warm weather is a welcome respite from the marine layer we’ve had for more than half of the summer.
We saw a lot of bird guano on the dock. White indicates birds are eating fish. Red guano is from a diet of krill, and purple or dark guano is from eating cephalopods or mollusks such as the squid with their ink sacks.
We saw a couple hundred birds on the floating bait dock. Wading birds included the Great Egret, Snowy egret, Great blue heron and Black-crowned night-heron. Brandt’s cormorants, Western gulls, Heermann’s gulls and Brown pelicans were the most numerous of all the seabirds.
Once through the Mission Bay Channel, we passed a few brightly colored buoys marking the artificial reefs used by the scuba diving community. Diving from a boat and onto shipwrecks are advanced dives. You go with a dive master on the HMCSW Yukon, a Canadian destroyer, that was sunk intentionally 25-years ago. The dive site is known as “wreck alley”. The Ruby E is the other prominent wreck, both about a mile offshore from Mission Beach.
Just 40-minutes into our trip about 2.5-miles offshore of Bird Rock, LaJolla, we came across a pod of about 120 long-beaked common dolphins. They were all porpoising at the surface when suddenly, every single dolphin dove down instantly and disappeared for a minute. Captain Bryan showed me the echo-sounder on the bridge, also known as a fish-finder, in which a ping is sounded and bounces off of anything solid. We saw a narrow band of dense fish from 80 to 100 feet down. The bottom only 140’, so one of the dolphins was echo-locating on the forage fish deeper down and like a dinner bell, the entire pod dove deep down to chow down on a fish lunch. They are piscivorous, humans are omnivorous.
We got 12-miles to the northwest, off of Del Mar, and Captain Bryan found us a pod of about 150 Offshore bottlenose dolphins, much larger than the common dolphins. We could actually see them spouting from about 2-miles away. As soon as we turned around, out of nowhere, it seems, a huge pod of about 1200 common dolphins materialized. Somehow we did not see them on our way out. Like dogs eager to see their owners when returning home, the dolphins seemed eager to greet us and show off their consummate swimming and porpoising skills.
Warm weather and clear skies continued for our SUNSET TRIP. We had a lot of foreign speakers aboard from EF International Language Campus in San Diego. We appreciate learning from you and hope you all learned a bit from us.
The animals we look for will have home ranges or territories, feeding grounds and breeding grounds. The dolphins that we see don’t really migrate but occupy a large area of the ocean. Some dolphin ranges are expanding due to El Nińos and marine heat waves. We came across a super pod of Short-beaked common dolphins about 5 miles off of LaJolla. They were spread out over a mile in length and a quarter mile wide. The dolphins are cooperative hunters and work together to corral schools of forage fish such as the sardine or anchovy and then individuals take turns feeding. They echo-locate and each dolphin has a “signature whistle” that is equivalent to their name, so nobody in a pod gets lost and can find kith and kin.
On our way back, we were excited to have a nice sunset and anticipation rose amongst our guest passengers for the clear horizon and the possibility of a “green flash”. Sure enough, the tip of the setting sun turned green due to the light refraction through more atmosphere at the horizon. The bending of the light is what happens, and what we learned in physics class of the electromagnetic spectrum of light is ROY G BIV. Red Orange Yellow and GREEN, then Blue, Indigo Violet for lower energy wavelength to higher energy wave length. So, another bonus to a spectacular evening and sunset cruise. Hope to see you all on a whale watch soon. Cheers from all of us. – Naturalist Greg McCormack
