Night Rockpooling at Marazion!

Midnight Madness at Marazion! Photo copywrite Alan Barker

 What an amazing experience! Despite light drizzle our volunteers only Night Rockpooling session at Marazion causeway was far better than expected! Setting out in our wetsuits and high viz vests and head torches anyone looking on must have wondered what we were up to! Crabs were out and about everywhere and seemed very surprised to be disturbed by crazy humans with torches!
Standing in the shallows our torches attracted hoards of tiny mysid shrimps, prawns and juvenile fish. We were soon joined by inch long adult atlantic cuttlefish. these guys are absolute beauties and although we had seen some on the day time survey we were treated to far more sightings on the night rockpooling!

The survey highlighted once again the incredible diversity of life on this shore and proved that night rockpooling allows you to build a much more full picture of the species present. Particularly species that are more active at night such as fish, crustaceans and cephalopods!

https://www.youtube.com/watch?v=_KAGnqnXGWs&feature=youtu.be

Shore crab in Torch light, Matt Slater 

Atlantic or little Cuttle Sepiola atlantica (approx 20mm total length), Matt Slater 

Star Ascidian Bottryllus shlosseri - a colonial sea squirt (each star approx 5mm across), Matt Slater

Dahlia anemone glowing blue in LED torch light, Matt Slater

A tiny baby tompot blenny found beneath a large boulder. (length approx 2 cm). Matt Slater

A beautiful sea slug Eubranchus farrani found by Jake Meyers and Trudy Russell. (Length approx 10mm), Matt Slater

Decorator crab Macropodia spp (Width approx 4cm), covered in sea weed for camoflague. Matt Slater

Stand up Paddle Board reccie of Marazion eel grass beds with Ocean High

I was privileged to have the opportunity yesterday to try out a totally new method of marine surveying. Laurence Smith of Ocean High, Marazion took me on a Stand Up Paddle board (SUP) exploration of the shallow lagoon to the East of the St Michael's Mount Causeway. This is a terrific method of exploring the shallow waters  and we are hoping to go back to accurately map the eel grass beds found there.
From the high vantage point of a SUP board you can see down into the water and on a clear day like this one it meant we had a fantastic view as we glided over the surface. A video camera mounted beneath Loz'z board allowed us to capture video as we traveled. A GPS was used to record the position of the outer edges of the eel grass beds in this site.

It was a fantastic survey and we now know that a SUP is a good platform for this kind of work. As the wind started to pick up and ruffle the surface of the water I got in and snorkeled and was able to ground truth our survey area. Interestingly we found what appears to be evidence of storm damage sustained by the eel grass this winter. In many areas you can see exposed rhizomes from the eel grass and a clear step is evident where sand has been removed probably taking with it eel grass plants themselves.

Damage where the sand has been removed by storms - root like rhizomes are now exposed at the edge of the remaining eel grass rhizome matt. 

Healthy eel grass Zostera marina.

Loz and the Mount 

Hairy sand weed looking like coral - Cladostephus spongiosus

Leucernaryopsis cruxmelitensis Stalked jelly fish found on Ulva lactuca sea lettuce

A SUPs eye view of the lagoon - note large rainbow wrack plants, Sargassum muticum and Bifurcaria bifurcata in foreground. 

Juvenile ballan wrasse - bright green to help them camoflague against the eel grass and sea lettuce

Fantastic Marazion yeilds strange surprises!

The weather stayed fine for our Marazion Marine day yesterday and a large group of shoresearchers turned out for what proved to be another epic day on the shore!
We had a great turnout of families for the public rockpool ramble and, who could fail to be impressed by the beautiful eel grass beds and colorful seaweeds and anemones we found?
People were amazed at the variety of crabs found on the shore - edible crabs, velvet crabs, shore crabs, Montagu's crabs, long horned porcelain crabs, broad clawed porcelain crabs, hermit crabs and squat lobsters were all in abundance!

The water clarity was amazing at the edge of the eel grass beds (which we were careful not to walk on!)
And living among seaweeds were found yet more stalked jellyfish Lecernaryopsis cruxmelitensis.
David Fenwick found an incredibly rare double headed stalked jellyfish.A Siamese twin version of the Maltese cross species.

Thanks to all the volunteers who came along - most got the chance to see a stalked jellyfish and all enjoyed exploring a fantastic shore.

Rare to see a s legged cushion starfish! 

A beautiful gem anemone found by Tim Caulfield

Water clarity in the shallows around the edge of the eel grass bed was astoundingly good 

A five bearded rockling with a very unusual forked barbel

A beautiful day on the Shore

Zoe at the shorelab

Red sponge found in an upper shore pool

Stalked Jellyfish Bonanza at Mounts Bay

Despite the terrible weather that Cornwall suffered this winter the shore at Marazion was extremely biodiverse for our Shoresearch survey day last Saturday!

A total of 15 volunteers turned out and all were treated to sightings of the nationally rare Stalked jellyfish that are a Feature of conservation interest for this site!  Local naturalists David Fenwick and Dr Paul Gainey joined us in exploring the lower shore shallow eel grass lagoon to the East of the Causeway to St Michaels Mount and straight away we were recording rare stalked jellies.



In total we made:
9 records of Haliclistus octoradiatus -  (5 in the lower shore lagoon and 4 in upper shore pools).
1 record of Leucernariopsis campanulata
1 record of Craterlophus convolvulus 
and 15 records of Leucernariopsis cruxmelitensis

In the past week David has recorded many more Stalked jellies so we now have definite proof that this area is important for these rare protected species. In fact numbers have been so large that it has been described as a bloom! Why this has occurred is not clear and more research needs to be carried out to investigate such rare population explosions.

Maltese Cross Stalked Jellyfish Leucernariopsis cruxmelitensis photo by Matt Slater

Using a hand held GPS Jason Birt was able to record the shore-ward boundary of two large eel grass beds - again a feature of Conservation interest to the site. We discussed with Laurence Smith who runs a stand up paddle board school at Marazion the possibility of returning when the weather is good to map the outer extent of the beds by snorkelling and from paddle boards. It sounds like a great idea - please get in touch if you would be interested in helping out with that!

Long horned porcelain crab magnified! 

Shoresearchers surveying an eel grass filled lagoon

Portrait of a worm pipefish

Generally the level of biodiversity in the site was very high, we recorded lots of Sea hares among the eel grass, and every boulder you looked beneath was home to porcelain crabs, both long horned and broad clawed, Montagues crabs and worm pipefish!

H. octoradiatus by Matt Slater - note the spherical primary tentacles
and the more randomly placed spherical nematocysts

After surveying the lower shore eel grass beds we moved up to a high shore site near the village of Marazion and again found lots of stalked jellys living in pools often attached to wire weed Sargassum muticum. A total of 4 more Haliclistus octoradiatus were found there!

A fantastic day out - and thanks to all of you for turning up!

Looking forward to seeing you over Easter at our next survey on 16th April again at Marazion!

Cheers


Matt