Sexy Saturday - Horseshoe Crabs

It's almost time for the horseshoe crabs again.  In the cold winter months, they go to deeper water and bury in the mud, waiting for spring. (Like the rest of us!)  As we start diving regularly again, we always see mating pairs of horseshoe crabs scooting around on the bottom. Here is their story;
The American Horseshoe Crab (Limulus polyphemus) is not actually related to a crab at all.  They are more closely related to scorpions, ticks and land spiders.  They are however, one of the longest surving species, with a design basically unchanged in 250 million years.  Their hard curved shell makes it difficult for predators to turn them over and they can adapt to big changes in temperature and salinity. A horseshoe crab can go without eating for almost a year if necessary.
Each spring during a new moon or full moon high tide, male horseshoe crabs start migrating in toward the shoreline.  Once the females start to arrive, the males release a pheromone into the water to attract them and use their compound eyes to spot a potential mate.  Once a female has been selected, the smaller male uses a glove-like claw to attach to her shell.  The female then drags the male in toward the beach.  Every few feet on shore, the female digs and deposits as many as 20,000 eggs.  The male fertilizes the eggs as he is pulled over the nest.
A female may lay as many as 90,000 eggs each season, but with very high predatory rates only about 10 percent survive to adulthood.  The eggs of the horseshoe crab are an important source of food for migratory shorebirds, and many species of fish feed on larvae or recently molted juvenilles.
For more information, NOAA has a whole website devoted to the the horseshoe crab. http://www.http//www.ceoe.udel.edu/horseshoecrab/

The best is yet to come.......

We went scuba diving on Sunday.  How could we resist a sunny day with temperatures in the fifties?  It was wonderful.  Although the water temperature was only 37 degrees, we knew that it was the last time that it would be that cold.  Now, with each passing day of warmth, the water will get warmer and warmer.  Drysuits will be put back in the closet and the wetsuits will be donned.
The visabilty on Sunday was great, allowing us to drift apart while still keeping an eye on our buddies.  We saw sand worms starting to wiggle about and a few very small creatures which we will have to look up in our reference books.
We are looking forward to a great season for diving this year.  There are wreck dives scheduled and our Advanced Diver course starts next Tuesday.   If you are interested in a refresher course, call us or e-mail.  There is so much great diving to be done in our area,  and it would be our pleasure to help you experience it.
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Sexy Saturdays

STOP in the name of love........ The Stoplight Parrotfish is a coral reef dwelling fish that can change sex.  These fish are generally located throughout Florida, the Bahamas and Caribbean. In the initial phase of life, the Spotlight Parrotfish could either be male or female.  In many cases, all fish begin life as females and change later in areas that lack breeding males or females. Fish in the initial phase are usually drab colors of red, grey, brown or black.  After the third year of life, a female may change into a male. This is refered to as the "terminal phase."  A male that was once a female is called a "Supermale" and will generally pair with one female to spawn.  A male that has not changed is called a "primary male" and will generally mate with several females. A Supermale is very colorful with combinations of bright green, yellow, blue and red.
The Spotlight Parrotfish spawns all year long, but has greater activity during the summer months. Males and females migrate into deeper areas of the reef to spawn.  The fertilized eggs are negatively buoyant and hatch within 25 hours to release larvae.  These larvae have no eyes, mouth or pigmentation for the first three days.
 A Spotlight Parrotfish can live up to ten years and can also undergo sex reversals at any time during their terminal phase.

"I wanna live forever...."

The fish with the shortest lifespan is the Pygmy Goby.  This fish is hatched, grows up, reproduces and then dies within 59 days. The Pygmy Goby (Eviota sigillata) is typically found in the Great Barrier Reef, or on the shallow reefs of the Pacific and Indian Oceans. Hatched from tiny eggs, the young gobies have been vigorously protected by their father.  A male goby will watch over the eggs while fanning them with his fins to provide more oxygen.  Once they develop as ocean larvae (3 weeks) , they settle onto a coral reef and grow to sexual maturity (10 days).  During her short lifetime, a female will lay three clutches of about 130 eggs.  This means that the Pygmy Goby species produces a new generation every 49 days, and up to 7 generations a year.

     The Pygmy Goby is only about 1/2 inch long.  In order to determine age, scientist cut into the goby's "otoliths" or small stones in the head.  These stones record the fish's age with growth rings, much like measuring the age of a tree.  Scientist attribute the "live fast, die young" pattern as an evolutionary response to predation.  The gobies lose at least 1/12 of their population every day to natural predation.

A "Valentine" Sexy Saturday

                                           "Do you take this seahorse....."

That's right, a seahorse mates for life.  In the wild, a seahorse will pick a partner for one or more breeding seasons.  The courtship of a seahorse is a lovely display of color and dance.  Several days before mating, a seahorse couple will link tails and swim together in synchronized movement.  They change colors with vibrant displays that last for hours.  In fact, even after the breeding season has ended, a seahorse couple will greet each other daily with a dance display before separating for the rest of the day.
During the mating season, the males prepare their brood pouch by filling it with water. As the male opens his pouch wide, the female "docks" and deposits 200 to 600 eggs  during their dance.  The male then swishes his body back and forth to distribute the eggs within the pouch.  The male then holds the developing babies for 3 to 6 weeks.  When the babies are ready to be released, the male suffers labor pains as he pumps and thrusts to expel the tiny bodies.  The baby seahorses are generally one centimeter long and must immediately fend for themselves.  Please see the January 15th blog on this site for a picture of this event.  Although a seahorse will only live a few years, a mating couple can produce between 50 and 200 babies each mating season.  Happy Valentines Day!

Sexy Saturdays

Are there male and female jellyfish?

The answer is "yes". Jellyfish have reproductive organs called gonads. When the time comes to make new jellyfish, a male releases sperm through its mouth into the water column. A passing female siphons some of the swimming sperm and fertilization occurs within the body or in brood pouches. These brood pouches are located on the oral arms of the jellyfish. After some early development, small swimming larvae leave the body or brood pouch. Once in the water column, they attach to solid rock or shells on the sea floor. They transform into polyps which feed on microscopic organisms passing by. Eventually these polyps multiply and form stacks of larvae discs called ephra. After months of development, each of these stacked ephra break off and develop into a adult or Medusa jellyfish.

Homboldt Squid in California waters

The Homboldt Squid were first discovered deeper than a thousand feet in 1997 by submersible cameras. There were only sporatic sightings throughout the years, until this week. As of last Friday, fishermen off the California coast have been catching their limit of these Jumbo Squid also known as Diablo Rojo (Red Devils).

The squid are normally found in depths of 660 to 2300 feet in the Humboldt Current area of South America. Some researchers attribute their new presence to changes in populations of both predators and prey. The drop in Pacific Hake population, a species of whitefish is affecting their normal food source and forcing them into shallower water. Overfishing of sharks, large tuna and swordfish allows the Jumbo Squid to hunt more easily.

These Jumbo Squid have a life span of just one year, but can reach as much as 100lbs. and up to 6 feet in length. They hunt in schools of 1200 or more and can swim at speeds up to 15mph. It will be interesting to track their activity now that they have "made contact" with humans. There is no way of knowing how long they will be around, but with so many anglers out trying to catch them, probably not very long.