dannythedolphin
The following is an extract from information found on the South Devon AONB website.
Birds
The Dart is a hugely productive environment and supports a large number of bird species. Herons, little egrets and cormorants kingfishers can all be seen catching small fish within the estuarys creeks.
A walk alongside the estuary can provide excellent views of redshank, greenshank, dunlin and oystercatchers. Mute swans and shelduck can also be seen sifting the mud for invertebrates, small shellfish and aquatic snails.
Mud - The life blood of the estuary
When the tide goes out large expanses of mud can be seen in the Dart estuary...the very life blood of the system!
Within the mud there are incredible numbers of bacteria which are working to break down organic material deposited by the river and incoming tide.
In one teaspoon of estuary mud there can be as many bacteria as there are people on the planet!!
There is so much organic breakdown in the mud that just a few centimeters below the surface it is annoxic and black where sulphate reducing bacteria release hydrogen sulphide giving the estuary its characteristic smell.
The mud provides an ideal habitat for several types of burrowing infauna including worms, snails and shellfish. Although somewhat species poor mudflats are one of the most productive habitats on the planet supporting huge numbers of birds, fish and other life.
Oyster Mariculture
The Dart estuary has a long history of shellfish cultivation and has a designated shellfish area located at Waddeton. Within the estuary sustainable shellfish production is practiced providing a valuable contribution to the economic well being of the local community.
Shellfish filter the water, feeding on plankton and exchanging oxygen across their gills, absorbing pretty much everything that comes their way. For this reason they act as wonderful indicators of environmental water quality like 'miners' canaries' for the estuary.
Crab Tiling
The collection of shore crabs for fishing bait is a traditional activity in West Country rivers, which provide the most prized (and valuable) 'peeler crab' bait. 'Peeler Crabs' are collected throughout the year, but mainly in the summer season by private individuals, angling associations and commercial collectors.
Increased activity on neighbouring estuaries had led to the introduction of restrictive bye-laws. As a consequence, the collection effort was being focused on other estuaries, east and west of Plymouth. The perception on the Dart was that there were a few hundred crab tiles in the estuary, not all of which were actively tended.
The Dart Estuary Environmental Management (DEEM) commissioned an undergraduate research project to look at the issue and suggest management options. A landmark study was the result which was so thorough in its comprehensiveness that it became the standard methodology for surveys of this type in what is now recognized as a regional/national issue.
The Dart study revealed that there are in fact some 12,000 crab tiles on the estuary. All these crab trapping areas have now been catalogued and assessed to provide a database against which changes and impacts can be monitored. The work on the Dart Estuary, and other estuaries in the South-West, has led to the adoption of a Code of Conduct advising bait collectors on best practice. This will encourage the practice to be conducted in a sustainable way
For further information please dowload/view the Crab Tiling Code of Conduct and estuary Map
Dolphins In the Dart
Dolphins and basking sharks are regular visitors to our coast and on occasion will venture into the estuary.
The estuary is a confined space for these large animals and can put pressure on their navigational senses. If you are out on the water with these animals it is advisable for your safety and theirs that you do not approach them too closely and always follow the code of conduct.
- Always let them decide what happens
- Keep your distance - never closer than 100m
- Never drive head on-to, move between, scatter or seperate groups of animals
- Take special care with mothers and young
- Avoid repeated changes in direction or speed - maintain a slow 'no wake' speed - if animals keep heading away or your activity is distressing them, slowly leave
Please be aware that harrassment of some of these animals is a criminal offence.
Fish
The Dart estuary provides excellent feeding and nursery grounds for a wide variety of fish. The productivity of the estuary supports several commercially important species including sea bass, plaice, pollack and sea trout. The estuary is also host to populations of sand smelt, sand goby, mullet, flounder, wrasse and pipefish.
Seal Haul Out Point
There are several seal haul out points within the Dart, allowing seals from the Mew stone that follow fish into the estuary a place to relax and do a bit of 'sunbathing'.
Wash
There can be a problem with the amount of wash produced by boats as they travel up the estuary. High speeds and increased wash can cause disturbance to the wildlife and can disrupt other peoples enjoyment of the estuary.
There are speed limits effective in the Dart estuary.
Continued use and enjoyment of the estuary is actively encouraged but please try to minimise your disturbance on the wildlife and other people whilst out enjoying the area.
Mew Stone
The Mew stone is a rocky outcrop a short distance outside the mouth of the estuary called such because of the population of nesting gulls (or Mews) which it supports. The Mew stone is a haven for seals and the rocks provide an ideal place for them to haul out and dry off. This is an excellent place to watch these charismatic animals but they are best watched from the land and if you are on the water their disturbance needs to be minimised. Disturbance to seals can interrupt their resting time and therefore result in lower fitness and reduced health of the seals. If there is interference with nursing young it can result in reduced health of the pup or separation of the pup from its mother. Seals may also abandon haul out sites if disturbance is too great.