Conservation of Smelt in the River Thames.

In March I went to a training day to become a volunteer citizen scientist for the project, "Conservation of Smelt (Osmerus eperlanus) in the Tidal Thames. which is currently being run by the Zoological Society of London. My role is to carry out regular weekly surveying at our allocated site in Westminster. 

The project was given funding in order to locate the areas that Smelt are breeding in the Thames. The fish was once very common in the river but due to pollution and habitat destruction they disappeared, recently seeing a return due to improvements in water quality.  This project is necessary as the species is still threatened and is very important as an indicator of good estuary health as well as for a balanced ecosystem.

Myself and Charlotte surveying.

Our bag of equipment contains items such as a ruler,
charts for the identification of species and a magnifying glass.

Surveying is carried out at low tide, so we may also try and find any eggs or hiding elver under rocks in the water. So far we haven't found any Smelt fry or eggs, but they have been found at other locations being surveyed across the river such as Putney and Hammersmith. Unfortunatly it is beginning to look like our site isn't very attractive to fish!

We have however, found many snails, amphipods and worms! Often when we turn up there are some interesting visitors, such as these ducks which are usually seen swimming nearby or napping on the river bank before we come down and disturb them.

For more information on the project, feel free to visit: http://www.zsl.org/conservation/smelt-osmerus-eperlanus and the ZSL Twitter for updates.

My Red-eared slider find.

I currently volunteer locally at a place called Lee Valley Regional Park. Here I meet up with the regular bunch of conservation volunteers carrying out practical tasks and activities in the parks green and open spaces.

Last week on a clean-up of Walthamstow Marshes, I was surprised when I spotted a Red-eared slider (Trachemys scripta elegans) on the bank of the stream! I brought this to the attention of the ranger leading the activity and he phoned the management to see if they would need it removed. This area is a designated Site of Special Scientific Interest and this sub-species of pond slider is invasive in the UK, so it was to be taken away to a wildlife centre who had agreed to collect it and take care of it from there onwards.

"Terry."

 This one could have been an escapee, or was deliberately released. Originally found in southern USA and Mexico, the first sliders were introduced to the UK as unwanted pets that grew larger than expected. A boom came about from the popularity of the children's television show "Teenage Mutant Ninja Turtles" and this species in particular has become the most widely traded pet turtle in the world.

FrogFest continued..

 The pond was completed just in time as it was only a couple of days before the pond was full of frogspawn!

At this stage I left the pond well alone to allow the spawn to develop and see what happens. I was hoping the pond would be well enough established by the time the tadpoles were ready so there could be enough food for them to be successful.

There was fairly warm weather during this period and so the tadpoles began to come out in a couple of weeks and suddenly there was a boom of activity in the pond.

Hundreds and hundreds of tadpoles all started spawning. It appeared that the majority of the frogs had dispersed by this time, only one was seen occasionally popping up to the surface but there is a possibility that there were more still in there.

 

I was concerned considering how new the pond was, that there was not going to be enough food availability yet. After some research I went and bought some fish flakes and sprinkled some in, triggering what can only be described as a feeding frenzy. Originally I wasn't sure how they would take to them but clearly tadpoles are quite keen on goldfish flakes!

Currently the tadpoles seem to be developing well, the weather has been incredibly good and has created ideal conditions for them. So hopefully they will have some success and I will see a few froglets in the near future!

FrogFest

Being the beginning of spring, it was time to start planting some seeds in the garden. The garden hadn't seen much activity over the winter so it was great to get out there again. Disturbingly, a dead frog lay on the lawn. Upon further inspection, it would appear the frog may have been attracted to a small collection of filthy water that had gathered at the back of the garden, reserved as the re-wilded nature area. I poked around in the water to see if anything was in there, and was confronted by another dead frog floating in the water. Concerned that perhaps this was attracting unsuspecting frogs to their doom, I decided to empty it out and fill in the hole. Whilst netting out the dead frog, it became apparent that this was home to live frogs as well! A total of eight individuals were found living in this tiny bit of water, including two currently breeding pairs.

Competition for the female.

The frogs were briefly transferred to a box filled with cleaner rain water whilst I scooped them out of the sludge in order to make a count. Contemplating this predicament, the logical next step seemed clear ..... Make a proper pond! And so started a new garden project. Aware that there was potential that the two breeding pairs were ready to lay their spawn any time soon, time was of the essence. I researched pond creation online and created a plan of action.

Digging!

The next day I rose early to get started on the pond. I began by marking out the area and shape using string and proceeded to dig it out for a good 3 hours. The pond ended up a lot deeper than I planned, I must have got a bit carried away! I created different levels of depth and the front area had a sloped shelf that would hopefully allow for easy access as well as escape for any other wildlife that may fall in.

The completed hole.

Considering this was the first project of this sort I have ever attempted, the dimensions were not perfect and it wasn't entirely flat at the bottom due to limited tool availability. However, a trip to B&Q got me some nice cheap bags of sand as well as a pond liner, which was *JUST* big enough! Phew. The sand worked well to smooth out the hole and prepare it for the pond liner to avoid it getting punctured, and using a bag of large pebbles I also bought from the store, I placed the liner and secured it with the pebbles placed around the edges.

At this point, it was starting to get dark, and there was only time to half-fill the pond and begin to put in the shingle base, so the rest had to wait until the next morning once it was light again.

I went out early in the morning to check on the frogs, and all 8 had moved from the temporary container to the half-filled unfinished pond.. along with 12 extra frogs that had arrived over night!!!

The shelf design was definitely going to be a hit.

I can only assume they were pleased with what I had so far created considering they all got in immediately despite it only being half done! I proceeded to continue filling up the pond before heading out to buy some aquatic plants from a specialist shop nearby I had looked up. I was mainly interested in oxygenators to keep the water healthy as well as providing food and shelter for the frogs and, hopefully, tadpoles. I ended up with a nice variety of oxygenating plants, native to the UK.

My submerged plants included Hornwort (Ceratophyllum demersum) and Curled Pondweed (Potamogeton cristpus). A Slender Club Rush (Isolepis cernua), which is a small oxygenating grass, was planted on the main shelf. The submerged plants were planted in pots and stones were used on top to keep them in place and sink them to the bottom of the pond.

Hornwort

The next step of the project will be to make the edges of the pond tidier and more natural, with an overall aim of planting some other varieties of flora around the sides for aesthetics as well as protection. But for now, the pond is completed and the frogs have somewhere decent to stop by, and hopefully this will mean a reduction in fatalities in the garden!