Port Fairy Key

Port Fairy Cuttlefish A key to the species found on Port Fairy Beaches Prepared by John Miller, Port Fairy. April 2020

Five cuttlefish "bones" (called a , sepion or sometimes ) are commonly washed up on Port Fairy Beaches. The identification “key” below will allow you to work out which species you have found.

To use the species key: • Make sure you have the whole cuttlebone or at least the posterior end (the end with the spine). • Look closely at the specimen you have found and identify the various features asked for in the key (page 3). • Read the two clues with the same number (e.g. 1a and 1b) then select the option that best matches your specimen. Specimens will vary so you are looking for the best fit, not necessarily a precise fit. • The best option will then either give you the name of the species or tell you to move on to the next number clue. • Work your way through the key then check you results against the species pictures (pages 4 - 6).

Live Cuttlefish (from Google images)

1 Port Fairy Cuttlefish Key

Port Fairy Cuttlefish species key

Note that the key may only work on the south-west coast of Victoria and nearby South .

1a Cuttlebone has a spine at the posterior end; back of cuttlebone Go to step 2 usually quite pinkish; length up to 20cm but usually smaller 1b Cuttlebone has either no spine or just a small rounded bump; back is apama Giant Cuttlefish - white and flat at the anterior end; often very large up to 40cm long very common 2a Spine very small (2-3mm); cuttlebone up to 5cm long; very narrow Sepia braggi Slender cuttlefish - and curved upwards near the spine uncommon 2b Spine 5mm or longer; cuttlebone usually longer than 5cm and never Go to step 3 markedly curved upwards near the spine 3a Spine sitting on a raised area; small pit below the spine on the front Sepia New Holland side; rough warty area on the back near the spine novaehollandiae Cuttlefish - common 3b Spine not sitting on a raised area; no pit below the spine; not warty on Go to step 4 the back The next two species are similar and more difficult to distinguish by the cuttlebone 4a Spine thin and very pointy up to 1cm but may be less; rear end Sepia cultrata Knifebone Cuttlefish abruptly narrows to blunt point; usually widest at 2/3 the length. - uncommon 4b Spine stouter but still comes to a fine point; anterior end narrows Sepia hedleyi Hedleys Cuttlefish - gradually to a rounded point, usually widest about the middle. very uncommon

2 Port Fairy Cuttlefish Key

Cuttlebone features

Front view

Outer cone

Spine

Soft: can be marked with fingernail

Inner cone

Back view

Dorsal end

Ventral end Hard: cannot be marked with fingernail

3 Port Fairy Cuttlefish Key

Species Information Giant Cuttlefish

Very large Hump outer cone

• Mature specimens very large, up to 40 cm long, white; large outer cone • Either no spine or just a very small rounded spine • Flat back at ventral end • Marked hump on the front surface on larger specimens • Lives inshore to about 100m depth

Slender Cuttlefish Sepia braggi

• Small and thin • 5-6cm long • Very slender outline • Very small sharp spine • Very narrow outer cone • Upward curve near spine

4 Port Fairy Cuttlefish Key

New Holland Cuttlefish Sepia novaehollandiae

Raised warty area Pit

Front and back view Back view of spine Front view of spine • Spine on raised area • Back with a fine warty area near spine • Pit below spine • Pinkish on back • Usualy around 12-15cm long

Headley’s Cuttlefish Sepia hedleyi

• Usually around 8-10cm long • Similar to Knifebone Cuttlefish but less abruptly narrowed at the anterior end. • Usually widest about the middle • Short sharp spine • No warts or pit at the base of the spine

5 Port Fairy Cuttlefish Key

Knifebone Cuttlefish Sepia cultrata

• Small: usually around 6-8 cm long and 3 cm wide • Abruptly narrows at anterior end • Widest at about 2/3 the length from spine • Spine with a very fine sharp drawn-out point • No pit at the front base of the spine

Interesting cuttlefish facts

• They are molluscs – they are in the same Phylum as , oysters and • They are in the same Class (Cephalopoda) as and • They have 8 arms and two tentacles – the tentacles are used to catch prey • They have a ‘W” shaped iris (see page 1) • They are demersal – that is, they live close to the ocean floor but not on it • The cuttlebone is porous, so the can pump water into the cuttlebone to allow it to sink or pump it out to float • Different species live at different depth ranges in the ocean • Giant Cuttlefish 1m- 100m • Slender Cuttlefish 30m – 86m • New Holland Cuttlefish 200m – 210m • Knifebone Cuttlefish 132m – 803m • Hedley’s Cuttlefish 47m – 1092m • Their preferred diet is crabs and fish. • They can put on spectacular colour displays and are masters of camouflage • They are regarded as being amongst the most intelligent of invertebrates

• They squirt ink (sepia) as a defense if they are frightened

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