Species Profile: Dugong

Hello again, welcome back to animals under threat. Today, we will be covering the Dugong. Once driven close to extinction, the dugong is once again under threat from global warming, poaching and destruction of habitat. Say hello to the Dugong (Dugong dugon).

https://www.worldwildlife.org/species/dugong

The dugong is a marine animal that resides in warm coastal areas which contains their prefer choice of food which is seagrass. They are characterized by their large grey coloured body, short flippers, tail that looks similar to a whale’s and board bristled snout (Perrin et al, 2008). Even though they look similar to manatees, there are many differences between them as shown in the diagram below (Britannica.com).

Picture by Britannica.com

Dugongs can weigh up to 230-420 kg and can grow up to 2.2-3.4m in length. They cannot move fast and have no defence against sharks, Orcas and crocodiles with young dugongs hiding behind the mother if danger in present (environment.gov.au, 2019). Older dugongs may have scars across their backs from boat propellers. Dugongs may live in groups or pairs depending where they live as the seagrass beds that they feed on cannot support large groups leading to dugongs moving to find other seagrass beds (australianmuseum.net.au, 2019).

seagrass bed by https://www.worldwildlife.org/species/dugong

The reproductive rate of dugong is low as females invest much of their energy in raising a single calf. Female dugongs don’t bear their first calf until they are at least 6 years old and the calf takes up to 12-14 to be born (Perrin et al, 2008). The calf will stay with the mother for several years and the mother will not have another calf for 2-7 years (australianmuseum.net.au, 2019). Dugongs can live up to 70 years with the oldest recorded at 73 years old.

mother and calf by https://www.nationalgeographic.com/animals/mammals/d/dugong/ 

Dugong swimming by https://www.wwf.org.au/what-we-do/species/dugong#gs.i0mhy2

Dugongs are under threat from poaching, global warming and habitat destruction. Due to their slow speed, hunters have targeted dugongs for their meat, oil, skin and bones. Global warming and habitat destruction have affected the seagrass beds by destroying/polluting which harms the dugongs that fed on it (nationalgeographic.com, 2019).

Next time, we will be covering the largest marine mammal that has ever lived.

References

https://www.britannica.com/animal/dugong-mammal by Thomas O’Shea retrieved 2019.

Perrin, WF, Thewissen, JGM, Würsig, B, & Thewissen, JGM (eds) 2008, Encyclopedia of Marine Mammals, Elsevier Science & Technology, San Diego. Available from: ProQuest Ebook Central. [23 November 2019].

https://www.environment.gov.au/marine/marine-species/dugongs retrieved 2019.

https://australianmuseum.net.au/learn/animals/mammals/dugong/ retrieved 2019.

https://www.nationalgeographic.com/animals/mammals/d/dugong/ retrieved 2019.

Picture references

https://www.britannica.com/animal/dugong-mammal

https://en.wikipedia.org/wiki/Dugong

https://www.worldwildlife.org/species/dugong

https://www.wwf.org.au/what-we-do/species/dugong#gs.i0mhy2

Species Profile: Tiger Tail Seahorse

Hello again, welcome back to animals under threat. Today, we will be covering a species of seahorse that has gained vulnerable status due to bycatch, coastal development and trades. Please give a warm welcome to the Tiger Tail Seahorse (Hippocampus comes).

Paolo Rossi/Guylian Seahorses of the World 2005 (via Project Seahorse)

The Tiger Tail Seahorse belongs to the family of Syngnathidae which is a family of fish that includes seahorses, pipefishes and seadragons. The colour of this seahorse alternates between yellow and black with the stripes beginning at the belly and continue to the tip of the tail. Unlike most fish, the Tiger Tail Seahorse does not have scales, but bony plates which is arranged in ring throughout the body (Job et al, 2006). They are mostly found with their tail wrapped around a stationary object as they swim very poorly. Tiger Tail seahorse swim by using their rapidly moving dorsal fin and use pectoral fins to steer and use their long snout to suck up small fish/shrimp, coral and plankton (Lin et al, 2016).

Paolo Rossi/Guylian Seahorses of the World 2005 (via Project Seahorse)

https://animalcorner.co.uk/seahorse-anatomy/

Tiger Tail seahorses are mostly found in coastal areas of Southeast Asia, Thailand, Indonesia and the Andaman Island. Their prefer habitat are coral reefs, seagrass beds and macroalgal beds in shallow waters around 10m to the low tide line (Lim, 2015). Seahorses have a unique way of reproduction as they perform a courtship ritual that may last over several days. Male Seahorses carry the eggs in a brood pouch which can contain 1-2000 eggs. When the eggs hatch, the young are released from the pouch and are left to the mercy of predators or ocean currents (Morgan and Vincent, 2007).

https://www.seahorseworlds.com/seahorse-reproduction/

The main threats to the Tiger Tail seahorse are bycatch, coastal development and trades. The seahorses are caught by accident when fishing. Coastal development adds the risk on pollution to the seahorse’s habitat as it damages the reef/seagrass beds/macroalgal beds that the seahorse needs to survive. The pet trade/medicine trade is a big threat as the seahorse is used in traditional medicine and are popular as pets (Lim, 2015).

Seahorse and scorpion skewers by Ginny Freeman 

Next time, we will be covering the dugong as it has come under threat from many factors.

References

Job, S., Buu, D. & Vincent, A. 2006, "Growth and Survival of the Tiger Tail Seahorse, Hippocampus comes", Journal of the World Aquaculture Society, vol. 37, no. 3, pp. 322-327

Lim, A. 2015. Hippocampus comes (errata version published in 2018). The IUCN Red List of Threatened Species 2015: e.T41008A128958172.

Lin, Q., Fan, S., Zhang, Y., Xu, M., Zhang, H., Yang, Y., Lee, A.P., Woltering, J.M., Ravi, V., Gunter, H.M., Luo, W., Gao, Z., Lim, Z.W., Qin, G., Schneider, R.F., Wang, X., Xiong, P., Li, G., Wang, K., Min, J., Zhang, C., Qiu, Y., Bai, J., He, W., Bian, C., Zhang, X., Shan, D., Qu, H., Sun, Y., Gao, Q., Huang, L., Shi, Q., Meyer, A. & Venkatesh, B. 2016, "The seahorse genome and the evolution of its specialized morphology", Nature, vol. 540, no. 7633, pp. 395-399.

Morgan, S.K. & Vincent, A.C.J. 2007, "The ontogeny of habitat associations in the tropical tiger tail seahorse Hippocampus comes Cantor, 1850", Journal of Fish Biology, vol. 71, no. 3, pp. 701-724

Picture references

https://animalcorner.co.uk/seahorse-anatomy/

https://www.iucnredlist.org/species/41008/128958172

https://en.wikipedia.org/wiki/Seahorse By Shyamal

https://en.wikipedia.org/wiki/Seahorse By ginny freeman from Yokosuka (Kanagawa), Japan

https://www.seahorseworlds.com/seahorse-reproduction/

Species Profile: Nassau Groper

Hello again, welcome back to animals under threat. Today, we will be covering a species of fish that has an unusual name and is under threat from overfishing and habitat alteration. Please, give a warm welcome to the Nassau Grouper (Epinephelus striatus).


The Nassau Grouper is a fish that grows to over a meter in length and weighs around 25kg. It belongs to the Serranidae family that is commonly refer to as the grouper family. Depend on its environment, this fish can come to a variety of colours (Sadovy et al, 2018). They mostly live in the Caribbean Sea and adjacent water and it was once had large populations in the Bahamas. Its preferred method of hunting is to wait and ambush their prey and swallow them whole (Oceana, 2019).

Picture by Oceana website

Nassau Gropers prefer to live in reefs, rocks and ledges where they can easily find prey and bred. Nassau Gropers live to around 29 years and mature sexually at the age of 4-5 years old. During breeding season, the Nassau Groper leaves the reef that live in to travel to spawning areas. These spawning areas are not well known as they tend to be anywhere.

Current known habitat of Nassau Groper by Fisheries.noaa.gov

When it is time to bred, females will release their eggs first, then the male follows and releases his sperm. Any fertilized eggs will hatch 2-4 days after floating away to other areas and will feed on zooplankton until they reach 1-2 months and move to seagrass areas. When they get larger, they move to reefs in order to survive (Fisheries, 2019).

Picture by Enric Sala

The Nassau Groper is under threat from overfishing and habitat alteration. The coral that the groper depends on for cover and shelter is currently been damaged by global warming. This means that the Nassau Groper cannot camouflage to ambush prey (Sadovy et al, 2018). Overfishing of the Nassau Groper during breeding season has led to adult morality and increase risk of genetic loss (Oceana, 2019).

Next time, we will be covering a species of seahorse that is at risk of bycatch, coastal development and trades.

References

Sadovy, Y., Aguilar-Perera, A. & Sosa-Cordero, E. 2018. Epinephelus striatus. The IUCN Red List of Threatened Species 2018: e.T7862A46909843.

https://oceana.org/marine-life/ocean-fishes/nassau-grouper retrieved 19/11/19

https://www.fisheries.noaa.gov/species/nassau-grouper retrieved 19/11/19

picture references

https://oceana.org/marine-life/ocean-fishes/nassau-grouper retrieved 19/11/19

https://www.fisheries.noaa.gov/species/nassau-grouper

https://www.iucnredlist.org/species/7862/46909843 by Enric Sala

Species Profile: Smoky Mouse

Hello again, welcome back to animals under threat. Today, we will be covering a species of mouse from Australia that is currently under threat from human influence. Please give a warm welcome to the Smoky mouse (Pseduomys fumeus).


The Smoky mouse is a small mouse that is similar in size to a small rat. Most adult smoky mouses weigh between 38-68 grams with the body length been around 90mm. The Smoky mouse tail can be around 140mm long and pinkish. The fur of this species can be pale-gray/bluish-grey with a grey/white belly and dark hairs around the eyes (environment.nsw.gov.au, 2019). The geographic range of this species is difficult to determine as detection of said species is low, however majority of the smoky mouse have been found in south-eastern Australia (Woinarski, J. & Burbidge, A.A. 2016). They have been recorded to be seen in Victoria, NSW and Australian Capital Territory.

Smoky mouse by Parks Victoria.

Smoky mouse does not have a preferred vegetation community as they have been found in coastal areas to sub-alpine areas. They feed on seeds and fruit from shrubs but will also feed on small insects such as moths (environment.gov.au, 2019). This species may live in pairs, large communal groups with one male and five females or they may live by themselves. Females give birth to one/two litters in spring with the number of pups born ranging from 1-4 (environment.nsw.gov.au, 2019).

picture by Peter Menkhorst and Linda Broome retrieved 19/11/19

The Smoky mouse is under threat from human influences. Predation from introduced species such as the Red fox (Vulpes vulpes), wild dogs (Canis lupus dingo), and feral Domestic Cats (Felis catus) have led to a decline in Smoky mouse population. Changes in flora from fire regimes has also change the Smoky mouse’s diet leading them to find other source of flora to feed on (Woinarski, J. & Burbidge, A.A. 2016).

Next time, we will be covering a species of fish with an unusual name.

References

https://www.environment.nsw.gov.au/threatenedspeciesapp/profile.aspx?id=10686 retrieved 19/11/19

Woinarski, J. & Burbidge, A.A. 2016. Pseudomys fumeus. The IUCN Red List of Threatened Species 2016: e.T18550A22398566. http://dx.doi.org/10.2305/IUCN.UK.2016-2.RLTS.T18550A22398566.en. Downloaded on 19 November 2019.

https://www.environment.gov.au/resource/smoky-mouse-pseudomys-fumeus PDF retrieved 19/11/19

picture references

https://www.theguardian.com/environment/2016/jan/15/smoky-mouse-could-go-extinct-without-us-looking-say-victorian-scientists

https://www.environment.gov.au/resource/smoky-mouse-pseudomys-fumeus picture by Peter Menkhorst and Linda Broome retrieved 19/11/19