Life History/Reproduction

It is important to understand two things about reproduction in Sepia officinalis. First of all, this species is dioecious, meaning they have both male and female sexes (MarineBio Conservation Society 2013). Second, that cuttlefish only go through one round of reproduction and die shortly after; this means that they are a semelparous species (Onsoy & Salman 2003). To understand this concept better, it can be compared to a salmon spawning in a river and dying right after. It is possible for it to happen all year round, but there are significant jumps in mating between the months of March and June. When this cycle occurs, cuttlebones can be found washed up on ocean shores all over the world (MarineBio Conservation Society 2013). Compared to mammals, these cephalopods’ lifespans are extremely short (1-2 years) and may seem insignificant to a human who lives for a much longer time (PIRSA Fisheries 2013). This is probably because, in our mind, we connect time on earth with increased intelligence. However, the cuttlefish is much different and their high intelligence level is with them at birth (Wood 1998).  

MATING PROCESS           
The actual process Sepia officinalis go through during mating is quite fascinating and unique in many ways. Two things determine dominance between males: physical intimidation (no direct contact) and the best looking den during mating season (Boal 1997). Similar to some other animal species, the slightly larger males use color change as a signal of attraction towards females. Upon successful reception of this color queue, the pair will come face to face and grab ahold of each other using their arms (Wood 1998). The male will then shoot a sperm packet, or spermatophore, into a small opening near the female’s eye, called a buccal area, using a specialized arm called the hectocotylized arm (Dive the World 2013). This event is classified as internal fertilization since it happens within the organism and not in the open environment. After a short period, these spermatophores burst and sperm travels up the oviduct where the eggs can be fertilized (Wood 1998). Considering that there tend to be more males than females in a given population, there is an occasional situation of more than one male attempting to mate with the same female. When this happens, the last male to deposit sperm will ‘win’ as the father (Dive the World 2013). Following this, females lay clutches, or groups of eggs covered with a special ink; acting as an adhesive and camouflage from predation as well (Dive the World 2013). Putting it into visual perspective, these eggs are relatively large (6-9 mm), so this tactic of trying to disguise them is necessary (MarineBio Conservation Society 2013). While this series of events is occurring the male usually tends to his mate, acting as protector until the eggs are successfully laid on the seabed, whether it be rocks or coral formation (Onsoy & Salman 2003).

JUVENILE LIFE
After two to three months the young hatch into miniature versions of their parents, and are provided nutrients from a yolk supply until their first independent kill (Dive the World 2013). Unlike many other organisms, including their close relatives, cuttlefish are born with a highly developed brain and their behavior proves this. At just a few weeks old, they can be seen trailing tiny crustaceans for a meal and utilizing their defense mechanisms against potential predators (MarineBio Conservation Society 2013). Perhaps their rapid maturation gives reason to why these brilliant organisms only live for a maximum of two years (Onsoy & Salman 2003).           

 

To find out more about how the cuttlefish interacts with other species, click here.

 

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