RiverWise
Issue 20 ~ November 2019
The monthly newsletter of the Lower Breede River Conservancy Trust
How your membership
can help the Breede
All estuaries in South Africa are under severe pressure resulting from over-exploitation of natural resources, habitat destruction and deterioration of water quality.
If you take an active interest in, or use, the Breede River Estuary we hope that we can persuade you to become a member of the LBRCT and to support our endeavours on your behalf by way of your contribution to these efforts.
The authorities who are ultimately responsible for ensuring protection of our valuable natural resources are contributing, however, they simply cannot afford to allocate sufficient of their available funds to meet the estuary’s conservation needs.
Your membership contribution supplements the funds obtained from the licence fees paid by users of boats; the municipalities by way of supplementary grants constrained by their many other social upliftment and development imperatives, and grants from those government agencies to whom we are contracted.
There are 62 estuaries in the Western Cape and all need support. The Breede is one of the two largest and most important and we all need to play a role in preserving it. 100% of your membership subscriptions are put to the best possible use to help maintain the conservation infrastructure that has taken many years to put in place and initiate new projects such as:
• Turtle and penguin rescue transport
• Environmental education programmes
• Holiday activity programmes
• Funding conservation interns
• Printing brochures, pamphlets, posters and information packs
• Producing and erecting signage
• Materials and equipment for monitoring projects
For R 100 a year, you can assist us with all of the above and add your voice that is so important to ensure that your opinions and concerns are heard. The LBRCT can speak more authoritatively when dealing with the vast number of threats, regulations and legislation that already affect the estuary with the backing of a sizeable member base.
Please think about the future of the estuary and the importance of maintaining its good health for you and your children’s benefit through supporting our effort.
The African Spoonbill
Photos by Craig Midgley.
The African spoonbill is common throughout most of sub-Saharan Africa. It can be found on inland waters such as lakes, rivers, and marshes and is mostly absent from arid and coastal regions. It is mostly white with red legs and bare red facial skin. It has a long, greyish, spatula-like bill. They are gregarious in the company of other birds, and usually gather in small groups of 3 to 30 and rest in large groups of up to 1,000 with other birds such as ibises (to which they are closely related), herons, and flamingos. They are shy towards humans and will quickly fly off.
Their migratory patterns are not well known (Hancock et al. 1992, del Hoyo et al. 1992) and it is assumed that they are likely to make nomadic movements in response to local rainfall rather than truly seasonal movements. The breeding season varies throughout the range, and is also variable from year to year, being suspended in areas when seasonal rains do not occur.
African spoonbills are carnivorous and feed during the day. Their diet consists of small fish, aquatic invertebrates such as crayfish and water beetles. They wade slowly through shallow water near shore sweeping their namesake bills back and forth and snap prey into the spoon of their bill and swallow with a backward jerk of the head.
African spoonbills nest colonially with other species, usually in groups of 5 to 20 pairs (groups of up to 250 pairs or more have been observed). Mated pairs build flat, oval nests from sticks and reeds situated over or near water on partly submerged trees, in bushes or reeds, or on a rocky ledge and line them with leaves.
Spoonbill with chicks in nest. Photograph by Bram Piot.
Females lay clutches of 3 to 5 eggs. Both parents take turns incubating the eggs, with the female sitting most of the day on the nest and the male relieving her at night. The eggs hatch after 25 to 29 days, and both parents care for the hatchlings for another 3 to 4 weeks until they are ready to leave the nest and be independent. Within another 4 weeks, the young spoonbills begin to fly. Parents offer them food until they fledge. The young bird places its head inside its parent’s mouth and receives regurgitated food.
African spoonbills are vulnerable to a variety of predators, especially when young, but the most general threat to the species is habitat loss due to the drainage of wetlands in some parts of its extensive range and stable population throughout southern Africa. They are classified as a species of least concern by the IUCN, the world’s leading conservation organization.
November water quality
The water quality run was conducted over incoming spring high tide over 21 sites. At each site, environmental variables are recorded every half a meter from just below the surface to as close to maximum depth as possible. The Breede River Estuary salinity, expressed as Practical Salinity Units (PSU), recorded near the mouth on the estuarine bed was that of seawater (35 PSU) with 35.12 PSU recorded at Gov. Slip. Salinities as high as 20.19 PSU were recorded at Bush Pub.
Salinities below 10 PSU were recorded from Dave Taylor upwards. The water temperature showed a longitudinal temperature gradient developing with lower temperatures recorded near the estuary mouth (17.05 °C) and higher temperatures in the upper reaches (19.46 °C at the Pont). The water temperature in the lower reaches is influenced by the sea temperatures.
November bird count
During last month’s bird count, we were fortunate to see 41 species, of which 32 are water associated species. In total 860 birds were seen with the Southern Red Bishops and the males in their bright red and black plumage the most abundant bird (344 birds). In lower reaches, Swift Terns were recorded in high numbers (102 birds). A notable find was a single African Black Duck near Bobbejaankraans. The usual suspects were also seen on this trip: Egyptian Geese, Kelp Gulls, Blacksmith Lapwings and African Spoonbills. A variety of waders were also seen on the mudflats along the Breede.
An undesirable bird was also seen on the trip: a Mallard hybrid. These duck hybrids are a threat to our indigenous duck species, particularly Yellow-billed Ducks as they crossbreed with our local wild species.
Terrestrial birds
Water associated birds
November marine debris
The marine debris surveys were once again dominated by plastic-related litter. It is the most prevalent on Witsand Main Beach with 72.9% of all litter recorded. This included anything from microplastics through to straws and plastic bottles. The second most abundant litter types varied between sites with the Main beach and Blokke sites recording high numbers of rope pieces (12.7 – 16.3%).
The Oysterbeds survey site recorded a large component of glass-related litter (19.3%). Foam pieces, particularly pieces of polystyrene were an important litter type found on Blokke, while fishing-related litter was also important on Oysterbeds.
Cumulative marine debris collected for all areas:
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.