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Cuttlefish 101 with Pamela Jackson

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Did you know that Cuttlefish have 3 hearts?

It’s true! This is a Cuttlefish but don’t let the name fool you – it’s not a fish.  Cuttlefish are invertebrates and are considered Mollusks (which means soft body), in the Class Cephalopoda which includes Octopus, Squid, and the Chambered Nautilus. They’re fast swimmers that use jet propulsion and have an undulating body mantle for locomotion.  Cuttlefish have eight tentacles (arms) lined with suckers on the underside and two elongated feeding tentacles.  They have a beak that can deliver a venomous bite and…… greenish-blue blood.  Super cool!

Cuttlefish are nocturnal hunters and hide and rest during the day.  They are some of the smartest creatures in the sea due to their large brain-to-body size ratio.  Their average life expectancy is about one to two years.

Cuttlefish have an internal structure called a cuttle-bone which is porous, made of Calcium Carbonite, and provides buoyancy.  Interestingly enough, these oval shaped cuttle-bones are harvested and given to birds as a calcium supplement (which is why they smell fishy).

Cuttlefish use their ink sacs to squirt black ink to confuse and escape from predators.  They have the added ability to use camouflage to evade sharks, dolphins, seals, sea birds, larger fish, and other cuttlefish.  Cuttlefish are cannibalistic which means they feed on one another as well as eat fish, small mollusks, snails, clams, worms, crabs, and shrimp.

Known for their colorful flashing displays, Cuttlefish have special cells called chromatophores, pronounced (crow-Matt-uh-4’s), that can change color at the drop of a hat.  Located within the skin, chromatophores allow the Cuttlefish to change skin color tone and texture to blend into their surroundings perfectly.  Scientists have no idea how they do this because these animals are colorblind!

Find out more about marine life with Pamela at www.gotoceans.com.

Learning about marine animals has been Pamela's lifelong passion. As a young child she won a goldfish at a state fair. Her parents taught her how to care for "Goldie". Pamela fed and cleaned Goldie's bowl, watched her swim around, and even took her fish to school! Pamela moved to California to pursue her passion for the ocean. She graduated with honors and a degree from the Aquarium & Aquaculture Science Program - the only accredited program of its kind. A Professional Aquarist and children's picture book author, Pamela contributes her expertise to the popular global 'Got Oceans?®' education campaign that can be found at Facebook, Twitter, LinkedIn, and Got Oceans?® websites. A national featured speaker at venues such as ExplorOcean in Newport Beach, CA and the 2013 Presidents' Round Table at Saddleback College in Mission Viejo, CA, Pamela loves to work and volunteer at public and private aquariums to help teach people about the ocean and its inhabitants. Passionate, committed, and connected with a large and growing audience, Pamela is a voice for the ocean's inhabitants sharing her knowledge with the world... because the ocean matters!

Marine Life & Conservation Blogs

Creature Feature: Undulate Ray

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In this series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.

This month we’re looking at the Undulate Ray. Easily identified by its beautiful, ornate pattern, the Undulate Ray gets its name from the undulating patterns of lines and spots on its dorsal side.

This skate is usually found on sandy or muddy sea floors, down to about 200 m deep, although it is more commonly found shallower. They can grow up to 90 cm total length. Depending on the size of the individual, their diet can range from shrimps to crabs.

Although sometimes called the Undulate Ray, this is actually a species of skate, meaning that, as all true skates do, they lay eggs. The eggs are contained in keratin eggcases – the same material that our hair and nails are made up of! These eggcases are also commonly called mermaid’s purses and can be found washed up on beaches all around the UK. If you find one, be sure to take a picture and upload your find to the Great Eggcase Hunt – the Shark Trust’s flagship citizen science project.

It is worth noting that on the south coasts, these eggcases can be confused with those of the Spotted Ray, especially as they look very similar and the ranges overlap, so we sometimes informally refer to them as ‘Spundulates’.

Scientific Name: Raja undulata

Family: Rajidae

Maximum Size: 90cm (total length)

Diet: shrimps and crabs

Distribution: found around the eastern Atlantic and in the Mediterranean Sea.

Habitat: shelf waters down to 200m deep.

Conservation Status : As a commercially exploited species, the Undulate Ray is a recovering species in some areas. The good thing is that they have some of the most comprehensive management measures of almost any elasmobranch species, with both minimum and maximum landing sizes as well as a closed season. Additionally, targeting is entirely prohibited in some areas. They are also often caught as bycatch in various fisheries – in some areas they can be landed whilst in others they must be discarded.

IUCN Red List Status: Endangered

For more great shark information and conservation visit the Shark Trust Website


Image Credits: Banner – Sheila Openshaw; Illustration – Marc Dando

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Guarding Against Coral Invaders

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Protecting (Dutch) Caribbean Reefs from Unomia stolonifera

Recent reports highlight the concerning spread of the invasive soft coral, Unomia stolonifera, currently devastating Venezuela’s marine ecosystems and detected in Cuba. With the potential threat of its expansion to the (Dutch) Caribbean islands, urgent action and awareness are essential to safeguard marine biodiversity and local economies from possible catastrophic consequences.

Invasive species are animals or plants from another region of the world that don’t belong in their new environment. These species can have major ecological effects by decimating native flora or fauna. They can also cause large economic losses and impact human health. Invasive species also pose a significant threat to marine ecosystems worldwide, including the Dutch Caribbean. Among these invaders is the octocoral species Unomia stolonifera or “Pulsing Xenia”, originally from the Indo-Pacific. With its rapid growth and lack of natural predators, this species can outcompete native species and disrupt fragile marine habitats such as seagrass beds and coral reefs.

Background

The invasive soft coral U. stolonifera was first identified in 2014, off the coast of Venezuela. It is believed to have been introduced via the illegal aquarium trade.  Since this species can reproduce sexually and asexually (or fragment), even small pieces can regenerate to spread.  Once introduced it quickly took over shallow reefs and hard substrate at depths of 0-50 meters, outcompeting local corals and seagrass for space.  Follow on surveys found that this coral species exhibited average percentage cover as high as 80%, vastly outcompeting native corals. In highly colonized areas, fish are disappearing due to loss of habitats.

In 2022, during a survey conducted in Cuba by the University of Havana, an unknown octocoral was discovered which was later identified as the invasive Unomia stolonifera. It is suspected that the coral larvae arrived in ballast water from fossil fuel ships originating from Venezuela, as nearby sites adjacent to Venezuelan ports have been heavily affected by the invasion.

How to help

Prevention through continuous monitoring, particularly in high-risk areas such as marine harbors and oil facilities, is paramount. Early detection plays a pivotal role in mitigating the threat posed by Unomia stolonifera.

The public’s involvement and awareness are also vital. Local communities, recreational divers, tourists, and all stakeholders are urged to participate in early detection efforts by reporting sightings (photo, location and date) of this invasive coral to their respective Protected Area Management Organization (PMO’s)- the Fundacion Parke Nacional Aruba (FPNA)STINAPA BonaireCARMABI Curaçao Saba Conservation Foundation (SCF)Nature Foundation St. Maarten (NFSXM) and St. Eustatius National Parks (STENAPA). If an invaded area is confirmed, follow the recommendations by the local PMO’s.

Keys to Success

Despite the challenges, early detection is key to mitigating the threat posed by Unomia stolonifera. With continued vigilance, research, and community engagement, there is hope for containing this potential issue before it becomes a major threat.

About the DCNA

The Dutch Caribbean Nature Alliance (DCNA) supports (science) communication and outreach in the Dutch Caribbean region by making nature related (scientific) information more widely available through amongst others the Dutch Caribbean Biodiversity Database, DCNA’s news platform BioNews and through the press. This article contains the results from several scientific studies but the studies themselves are not DCNA studies. No rights can be derived from the content. DCNA is not liable for the content and the in(direct) impacts resulting from publishing this article.

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