The Deep Blue Sea

I grew up vacationing and fishing on a lake near Dayton, Ohio (Grand Lake St. Mary’s) that was about nine miles long by three miles wide and had a depth of less than seven feet.  So you can imagine my disconnect now when looking out our backyard and seeing humpback whales swimming past and ocean going cruise vessels entering  the Hilo Harbor.

"Valentine" in Backyard

This led me to wonder just how deep the ocean was off of our lanai, which in turn led me to the NOAA (National Oceanic and Atmospheric Administration) site which was brought to my attention by a friend of mine in Marine Science at the University of Hawaii - Hilo:  http://www.nauticalchartsonline.

www.NOAA

So the ocean seems to be about 14 feet deep near our cliff, then increasing to 25 feet in depth and quickly to 34 feet.  Beyond that the water becomes about 90 feet in depth which must be fine for humpback whales.  It seems that humpback whales seem to prefer "shallow/protected" waters and spend the majority of their lives in waters that are 300 feet or less, and in this case, considerably less  than 300 feet.  http://www.whalewatchmaui.com/maui.html

Credit: Devany Vickery-Davidson

From deep water on the north, there is a ship channel to the inner harbor edge to the wharves in Kuhio Bay. A Federal project provides for an entrance channel 35 feet deep and a harbor basin of the same depth in Kuhio Bay. Channel and basin are maintained at or near the project depth. www.NOAA

As you can see, our weekly Tuesday visitor, the “Pride of America,” has a draft of only 26 feet.

www.NCL

Humpback whales and the cruise ships seem to coexist peacefully.  We have even seen whales swimming next to the ship and “porpoising” in and out of the water next to the boat. 

Interestingly, the 20-fathom depth (120 feet) curve is seldom more than one mile from shore in Hawaii and usually not far from the coral reefs that fringe much of the island coastline. The bottom generally pitches off rapidly to great depths from a narrow coastal shelf. Under normal conditions the color of the water changes from a deep blue in the open ocean to a blue-green between the 10- and 15-fathom (60 feet to 90 feet) curves; and bottom features become visible at 6 to 7 fathoms (36 feet to 42 feet).  www.NOAA

“Happy, Happy Hump Day in Hilo”

That phrase perfectly describes the waters around the Big Island this time of year thanks to the humpback whale. Here is an incredible picture caught by my wife Devany off our lanai of two whales breaching at the same time (and no it wasn’t “photo shopped”).

The island chain insulates the water, warming it up to the perfect temperature for whales to give birth and raise their calves. And unlike Alaskan waters, Hawaii's waters are mostly predator-free. http://www.bellaonline.com/articles/art65278.asp

During their stay in Hawaii, they do not feed, but rely upon energy stored in their blubber. Instead of feeding, the whales devote most of their time to mating and bearing their calves.

Another interesting behavior exhibited by the humpbacks during their stay in the islands is singing. The "songs" of humpbacks are made up of complex vocal patterns. All whales within a given area and season seem to use the same songs. However, the songs appear to change from one breeding season to the next. Scientists believe that only male humpbacks sing. While the purpose of the songs is not known, many scientists think that males sing to attract mates, or to communicate among other males of the pod. http://earthtrust.org/wlcurric/whales.html

How humpbacks create these sounds is unknown since they do not have functional vocal cords. Last week my wife was kept awake at night by the sounds of the whales that sounded like haunting cries and others that had a trumpeting sound.

The Hawaiian Islands Humpback Whale National Marine Sanctuary was created by Congress in 1992 to protect humpback whales and their habitat in Hawai`i. The sanctuary, which lies within the shallow (less than 600 feet), warm waters surrounding the main Hawaiian Islands, constitutes one of the world's most important humpback whale habitats.

Through education, outreach, research and resource protection activities, the sanctuary strives to protect humpback whales and their habitat in Hawai`i. On January 30th and again on the last Saturday in February and in March, dozens of volunteers will fan out to an estimated 60 sites along the shores of O'ahu, Hawai'i and Kaua'i for the sanctuary's annual whale count. The count provides key population and distribution information on humpback whales around the Hawaiian Islands.

http://hawaiihumpbackwhale.noaa.gov

A main reason the humpbacks winter in Hawai'i is to give birth to their young, which like any youngsters are less adept than their parents at staying out of harm's way. David Mattila, the sanctuary's science and rescue coordinator, advises boaters to think of Hawai'i waters in the winter as analogous to a school zone when class lets out. "Drive carefully. It's a nursery." <http://www.honoluluadvertiser.com/article/20100129/NEWS14/1290364/Humpback-whales-thriving-in-Hawaii-as-annual-count-begins>

By the way, does anyone still call Wednesday, “Happy, happy hump day?”