Spotlight: Monk Seals, ‘living fossils’ of the sea

They’re the oldest species of seals on the planet, believed to have been swimming Earth’s waters for millions of years. And today they’re the most endangered marine mammals in the world.

Hawaiian monk seal. Photo courtesy Kaua’i Monk Seal Watch Program.

Hawai’i’s monk seals (Monachus schauinslandi) are one of two mammal species endemic to the islands (the other is the Hoary Bat). Long ago, Hawaiians named these creatures Ilio-holo-i-ka-uaua –  or “dog that runs in the sea.”

Mediterranean monk seals (Monachus monachus) were said in Greek mythology to be protected by Apollo and Poseidon, and were described by Aristotle and other Greek writers. A monk seal face was etched onto coins dating from the 6th century BC, found in the ancient city of Ionia, on the Aegean Sea.

The third recently known monk seal population, the Caribbean monk seal (Monachus tropicalis), has been declared extinct; the last one was sighted in 1952.

Mediterranean monk seal in cave. Photo by Giovanni Dall’Orto; via WikiCommons

Today, the Mediterranean monk seal population is precariously below 500 individuals and believed to be declining. They’re now found predominantly in caves and areas isolated from humans – not the open beaches where scientists believe they traditionally spent their time.

Hawaiian monk seals number less than 1,200 individuals, and are also believed to be declining in alarming numbers. A 2009 scientific study stated that Hawaiian monk seals face a genetic bottleneck, with the lowest genetic diversity of any mammal species ever studied.

Both populations are critically endangered, and face multiple threats – encroaching human populations, entanglement in marine debris and fishing gear, infectious disease and more. They also have a relatively slow reproductive rate compared to other seals.

Funding for their protection in both Hawai’i and Greece is not certain, particularly in these rough economic times.

Learn about these remarkable creatures here (Hawaiian monk seal), here (Mediterranean monk seal)here (the tragic Caribbean monk seal), and here. Keep up on latest monk seal news here.

And perhaps  figure out what you can do to help them make it through another million years on this planet.

Some ideas are here and  here for helping the Hawaiian clan; you can support efforts in the Mediterranean by adopting a monk seal here. (Use GoogleTranslate on this page)

Update 16 Feb. 2012: TV3 out of NZ has a good read on a male monk seal being relocated to Waikiki Aquarium because of aggressive behavior toward his brethren. 

Update, 27 Jan. 2012: this AP article is a good read – illustrating how NOAA’s efforts have been helping the critically endangered monk seal population in Hawai’i.

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Today’s Gulf sea turtle – Hawksbill

As The Baltimore Sun’s Candus Thomson notesall five species of sea turtles found in the Gulf are listed under the Endangered Species Act (this was pre-oil leak). We’re looking at fast facts about these species – this week, it’s the Hawksbill:

Hawksbill Sea Turtle
(Eretmochelys imbricata)

  • listed by US as a critically endangered species since 1970
  • average adult size is 2 1/2 feet and 95 to 165 pounds
  • adults feed mostly on sponges and other invertebrates
  • can live to be roughly 50 years old
  • named for unique hooked beak
  • females nest April through November, and typically not in groups
  • females can nest faster than any other sea turtles – can complete the entire process in less than 45 minutes
  • primary nesting areas in the US are in Puerto Rico, the Virgin Islands, and Florida’s SE coast and the Keys
  • global populations have declined 80% or more in past century

The Hawksbill sea turtle’s dramatic population decline is due to a variety of causes – habitat degradation, artificial lighting along beaches, marine pollution and debris, incidental take by commercial fishing operations, egg collection and hunting of adults for meat.

Another significant factor in the Hawksbills’ decline is trade in their lovely carapaces – primarily for “tortoiseshell” jewelry.

Legal trade in Hawksbill shell trade ended when Japan agreed to stop importing shell in 1993, but a significant illegal trade continues. Trade in Hawksbills and products made from them is prohibited by CITES (Convention on International Trade in Endangered Species).

Photo credits: Top photo courtesy Thomas Doeppner; bottom photo by Caroline Rogers, USGS

Today’s Gulf sea turtle – Kemp’s ridley

As The Baltimore Sun’s Candus Thomson notes, all five species of sea turtles found in the Gulf are listed under the Endangered Species Act (this was pre-oil leak). We’re looking at fast facts about these species, starting with the most endangered:

Kemp’s Ridley Sea Turtle
(Lepidochelys kempii)

  • the most endangered of the sea turtles
  • the smallest of the sea turtles, measuring 23 to 28 inches, and weighing up to 100 pounds
  • feed mostly on crabs
  • reach maturity at 10 to 15 years old, and can live 30 to 50 years
  • females nest from May to July, on beaches across the Gulf of Mexico
  • Padre Island National Seashore is one of the most popular nesting beaches for the turtles in the US
  • Kemp’s Ridleys are named after Richard M. Kemp, a fisherman from Key West, FL, who first submitted the species for ID in 1906

Kemp’s ridleys display what NOAA calls “one of the most unique synchronized nesting habits in the natural world”, called “arribada”— arriving in waves of hundreds on a single day on beaches in Mexico. Scientists discovered this phenomenon in 1947, when they saw an amateur video documenting an extraordinary arribada near Rancho Nuevo. It is said that approximately 42,000 Kemp’s ridleys nested during that single day. The video also showed locals harvesting more than 80% of the turtle eggs. The arribadas recorded since then have been much lower, numbering in the low thousands of nesting female turtles.

The habitat preferences of Kemp’s ridley hatchlings has led Florida biologist Blair Witherington to say they may well be “the poster child for what’s happening to wildlife” in the Gulf oil spill.

Photos courtesy National Park Service