RiverWise 

Issue 9 ~ December 2018

The Blue Dragon 

(and they say dragons dont exist...) 

When most people think of slugs, they probably don't think of the Blue Dragon. They most likely think of ugly green and yellow blobs that plague their garden patch. But this is a whole new kind of slug that you need to know about. Not only is the Glaucus atlanticus visually striking but it possesses capabilities that not many other creatures on this earth do. Blue dragons are part of the nudibranch family, a group of soft-body molluscs more commonly known as sea slugs. Though they look like the left-behind offspring of some alien creatures, these bizarre creatures are 100% Earth-bred. Although they are all quite beautiful, with a wide range of colours and specialized appendages, the blue dragon is the most visually stunning and fascinating by far. When fully extended, it looks like an alien dragon flying through the water on its colourful tendrils, known as cerata. There are some interesting facts about these nudibranchs, such as...

That namesake coloration is for more than just show. The sea slug uses the coloration to its advantage as it floats on the ocean's surface. The blue side of their body faces upward to camouflage it against the blue of the sea, while the silver side faces downward to camouflage it against the bright surface of the water. Predators looking down at it or up at it will have a harder time seeing the little slug thanks to those beautiful dashes of color.

 

This species of sea slug is not defenceless as it floats. If the pretty colours don't hide it well enough from potential predators, the sea slug's sting is its next line of defence. The slug isn't venomous all on its own. Rather, it stores the stinging nematocysts created by the creatures on which it feeds, including venomous siphonophores and Portuguese man o' wars.

These cells are stored and concentrated, so when it's touched, the blue dragon can release these stinging cells to pack an even more powerful punch than the man o' war hydrozoan. All blue dragons are hermaphrodites, meaning they have both male and female reproductive organs. When two blue dragons mate, they both produce egg strings. According to The Cephalopod Page, "Because of the lack of a hard substrate to attach the eggs to, the eggs often float freely in the water or are placed on the remains of prey until the larvae hatch." So not only do they steal poison from their prey but they also lay their eggs on them. (Talk about adding insult to injury.) These beautiful but dangerous sea slugs can be found throughout oceans around the world, from temperate to tropical waters. So if you come across one, it's best to admire it's beautiful blue colours from a distance. If you want to have something small to admire from close, there are always pendants for necklaces. 

Water Quality Run: 

December results 

 

~ Natural Salt ~

 

It doesn't take much to feel the salt in the air and nature doesn't lie. There was an increase of 10 PSU in the water at the estuary mouth! That's a big leap from November's reading of 23 PSU. The lack of fresh water in the system is the reason for the dramatic spike, but it is nothing be concerned about, nature takes its course. With a high start of 36 PSU, salt can be found throughout the whole system. So, for those of you upstream, take care when watering your gardens and note the salinity of the point closest to you. The saltwater in the system and the increase in temperature has made some great conditions for catching fish. Remember to practise some catch and release 🙂 

Site:Salinity (PSU):Temperature (⁰C):Turbidity (m):
Gov. Slip36.6720.713.8
Hotel35.8720.972.6
Mudlark34.4121.822.7
Goudmyn34.2822.82.5
Karoolskraal29.2622.091.9
Powerlines28.4722.321.9
13km from RM27.6722.981.8
White House23.9722.891.9
17km from RM21.0123.111.7
Bobbejaanskrans21.5623.431.8
Ronnies15.0123.551.9
Bush Pub14.9823.691.7
Kemp14.6823.791.7
Riverine13.8823.931.6
Blue Gums10.0123.981.6
Deprecia6.924.021.7
33km from RM5.3124.541.4
35km from RM4.9624.661.3
Dave Taylor4.6225.011.2
39km from RM3.7224.791.1
Pont3.1824.811.1

What all affects birding in the Breede?  

And they say woman can't multi-task. 

We took our data collection process to the next level. While on a compliance patrol, we decided to do a bird monitoring survey as well as update our Alien Invasive mapping of the upper streams of the Breede. Talk about having our hands full. We decided to test how much of an influence the time of the day, the weather and how busy the river is with regards to people boating, skiing and fishing, would have on the bird biodiversity. The first graph shows the count we did on the day we did a compliance patrol starting at 12:00 while the clouds were building, the wind was blowing and there were people boating from beach to beach. More than anything else, the weather definitely had the biggest influence on the number of bird species we saw. 

Species:Count:
African Darter1
African shellduck7
Blacksmith Lapwing4
Cape Cormorant6
Egyptian Goose45
Fiscal shrike1
Fish Eagle1
Hadeda Ibis4
Jackal Buzzard1
Kelp Gull5
Little Tern28
Pearl-breasted swallow3
Red knobed coot1
Sacred Ibis3
White breasted cormorant4
white rumped petrel2
Yellow-billed Duck14
Grand Total130

The second count we did was done early morning, on the water by 06:30 and counting from the river mouth up towards riverine with a slight wind, clear skies but over 20 boats fishing and 48 boats counted in transit or moored. We were still able to see over 30 species with special attention to the smaller waders of the estuaries and the seasonal birds such as the Martins and Swallows. It was seen that in the areas with a large number of boats fishing, Kelp Gulls and Little Terns were the most popular because they were using the fisherman to make their job of catching food easier (and they say birds don't think...) whereas in the quieter locations we were able to pay closer attention to the birds in the reeds and zooming over the water surface catching small flying insects.

Species:Count:
African Darter1
African shellduck2
African Spoonbill4
Black Oystercatcher7
Blacksmith Lapwing2
Blackwinged stilt5
Blue Crane2
Cape Cormorant4
Cape Turtle Dove 3
Cape Weaver 10
Common Greenshank9
Common Swift7
Common Tern8
Curlew Sandpiper12
Egyptian Goose12
Grey Heron3
Grey Plover14
Hadeda Ibis3
Kelp Gull7
Little Egret2
Little tern26
Pearl-breasted swallow1
Pied kingfisher2
Red Bishop10
Whimbrel2
White breasted cormorant9
White Faced Whistling Ducks6
White fronted plover1
White Rumped Swift2
Yellow-billed Duck5
Grand Total181

Fun in the Sun meets "Let's Bash that Trash"

~ A Clean Beach is a safe Beach ~

 

With the expansion of our conservation efforts to the banks and coast of Infanta, there has been a greater amount of data sent in which has been great. With more data comes more information about what is happening on our beaches. When the beach clean-up was done in Infanta, the items of most concern were Fishing Line, Foam Pieces and lastly but most importantly Glass pieces. A dead Cape Fur Seal was discovered on the beach with no obvious sign of the cause of its death. The Infanta community also assisted us in a local beach clean-up included in the December holiday programme. We had a great turnout where 6 adults and 8 kids took part. We walked from the Infanta Slipway along the coast until we reached the River Mouth. With all their hard work, 38 kg of trash was removed from the beaches with the weirdest things being collected; 3 separate car batteries, veld skoene, underwear and syringes. Unfortunately, a dead Cape Cormorant was also found along with the dead Cape Fur Seal with no obvious signs of death. A total of 115 plastic pieces were found along with 39 pieces of glass and a conglomerate of 20 odd cigarette butts found at the Fisherman’s Jetty. 

 

As for the Witsand beach cleans, we had some helping hands. The kids who participated in our educational programme recorded what they collected during their beach clean-up. In the spirit of supporting Witsand Main Beach being demarcated as a blue flag beach, we wanted to keep the beach as clean as the title describes. Blue Flag is an international annual award which focuses on the environmental management of our coastline and coastal waters to help tourism growth and development. The kids were in great spirits and collected 19 kg of trash! The most unusual item being a rubber tarp used for construction weighing 4,5 kg and measured 3,5 meters long. The item which is of most concern is the number of plastic pieces which in total was 198 pieces. 

 

The beach clean-ups were a huge success and great interactivity between the community and the Conservancy. It was inspiring to see so many children under the age of 14 who have an interest in taking care of something they love. It is an initiative that should be adopted by all. Even though there were less people at the Witsand Beach Clean-up compared to the Infanta Beach Clean-up, the kids of Witsand were able to pick up a total number of 607 pieces of trash and the Infanta community was able to pick up 213 pieces of trash. So, we have two winners, congratulations to Witsand for collecting the most items off the beaches and congratulations to Infanta for collecting the heaviest amount of trash off our beaches.  

Our Statistics: Total

0

Plastic Pieces 

0

Glass Pieces 

0

Cigarette Butts   

0

Fishing Gear

Thank you for reading

We hope you enjoyed this months' issue. Should you have any feedback, questions, or matters you would like us to cover in a future issue, please do not hesitate to write to us at news@breede-river.org.