We're invited to winter talks perombos conservation group At the Seiners Arms, it was designed by two divers, Chris Lewis and his wife Cathy, both members of the Divers Association Helford Conservation Group They captured everything they saw on the river bed, including sharks and rays! We were really intrigued and as we kayaked along the Helford River we had no idea what was beneath our feet. Helford Cluj Kayaking Adventure or Helford River Cruise.
The Helford River is very unique in that it is an estuary, a flooded valley, rather than a river. During the Ice Age thousands of years ago, sea levels rose, creating flooded valleys like Helford. Its shallow beds are home to an abundance of wildlife, including sharks and rays, and these videos were filmed at just 7 meters deep! it takes us back to our snorkel Lady Elliot Island, South Barrier Reef, Australia The filming location for Blue Planet.
Spinyback ray on the River Helford, Cornwall, UK
Rays in Australia's Great Barrier Reef
As we kayak along the Helford River, we don't know what's beneath our feet, but we're about to find out. The River Mull stretches from St Mawes in the shallows to Castle Beach before emptying into the River Helford.
This is a guest blog from Helford Conservation Group diver Chris Lewis
Helford is located within the Farr and Helford Special Reserve, partly in recognition of the diversity of invertebrate life found within it, and because it is an important breeding area for many marine species.
Diving usually takes place at a depth of approximately seven meters east of the Helford River moorings. The area includes two main habitats: seagrass and maerl (nodular pink calcified algae) and sand and mixed ground. Most of the footage was from Helford or the nearby Fal maerl riverbed, and although a few clips were from further afield, all species and activity were observed in the river. These materials cover just a few of the many stunning landscapes that can be found beneath the waves.
Mollusk
Double valve:
Some parts of the bottom are covered with bivalve shells, and the creatures themselves are buried beneath the seafloor. However, both king and queen scallops can be seen in the open or partially buried. Their simple eyes, of which there are two hundred in Queens, allow them to detect the approach of predators such as starfish and propel themselves to safety by slapping their shells to expel water.
Aplysia:
These sea slugs are both hermaphrodites and hermaphrodites. When mating in pairs you can play either male or female, but in larger groups you can play both! Sometimes, when everyone plays both roles, they form a complete circle, called a daisy chain.
Sea snail:
Large necklaces or moon shells are the most attractive appearance of our sea snails, but this hides their true nature. They are borer killers, using their harsh tongues to punch a hole in the bivalve shell and then inject digestive enzymes into it, liquefying their prey.
The conch is our largest sea snail and rolls across the ocean floor like a tank. They use siphons to detect chemical cues in the water that guide them to their prey. They also have harsh tongues but usually use brute force to open their bivalve meals.
The reticulated dog conch is probably Helford's most successful scavenger. They also sense when they are ready to feed and will quickly swarm around any part of the bivalve that has been eaten. After a bit of pushing and shoving, a lucky few will get to eat the remaining meat, while the disappointed latecomers will soon try their luck elsewhere.
Bandana top shell shows surprising speed transformation. They have otherworldly characteristics, sucking algae and diatoms from the seabed surface or from empty bivalve shells. Like many snails, they need the ability to self-correct to survive the rough edges and tumbles of the ocean floor.
Small benthic fish (fish that live on the bottom of the sea)
Painted Goby:
These fish, which are about the size of a pinky finger, are real and commonly seen in Helford. The male uses a single bivalve shell as a roof for the nest. They display their fins and call loudly (like a rapid drumbeat) to attract females to the nest to lay eggs for them to fertilize and guard. They also use their displays and sounds when competing with other males. The louder male usually wins the contest without violence, but if this display of power fails, the males will turn on each other. Successfully building a nest and raising offspring is a difficult task that takes everything they have.
To maintain energy levels, they spend a lot of time looking for food. A rather large polychaete worm found in the bed of the Mull River is quite the prize. Everyone wants a piece, so competition is fierce.
Xiaolong:
Like many bottom-dwelling fish, arowanas can change their color to better match the substrate in which they live. These common little dragons get their red color from living in mud beds. They feed on tiny invertebrates, taking a mouthful of sand and dirt, swallowing the edible food, and then spitting out any grains of sand. Finally, they forcefully expel the finer elements of mud from their pores, like a smoke signal. By feeding themselves, spider crabs expose the soil beneath the mud layer. If a crab molts or dies, the released nutrients will attract more invertebrates, and more dragons will join the smoking party.
Reticulosaurus has been described as the most beautiful fish in our oceans. But this only applies to males, who, like peacocks, put on a stunning display of color when on display. In contrast, women are relatively dull. The display of these fins is used primarily to impress the females, but also to intimidate other males. Courtship can take several hours and multiple displays before the female decides to lay her eggs and slowly ascends into the body of water with the male to release eggs and semen.
Hermit crab:
The back half of hermit crabs' bodies is soft, so they use their gastropod shell for protection, which most species need to replace with a larger shell as they grow. The two most common hermit crabs in Helford are the common hermit crab and the Prideaux hermit crab. They are omnivorous and can be seen eating a variety of foods.
In Helford, common hermits often have what are called parasitic anemones on their shells. The name is unfounded, as both sea anemones and crabs benefit from this arrangement. Sea anemones can hitch a ride and gain access to crab remnants, and the crabs are further protected because the anemones have stinging tentacles. This feature appears to be very valuable, as another crab lacking an anemone of its own may seek to obtain the shell of another anemone, especially if it possesses four such treasures.
Competition for food is often fierce. Even a small amount of leftover bivalve meat can attract legions of hermits eager for a piece of the pie. The result was a free-for-all in which most of the effort seemed to be spent on fighting rather than feeding, and despite all their efforts, it was the reticulated dog conches that took most of the prize this time. The bivalve has a hole in its shell, which means the original predator may have been a moonshell.
For Prideaux's hermits, possession of the so-called cloak anemone is a must. These anemones secrete a chitinous membrane that allows each crab's original shell to expand, so its inhabitants don't need to replace their shells as they grow. Since their diets are similar, both regular hermits and Prideaux hermits compete for the same food.
When mating, both sexes need to leave their shells. The male will latch on to the female when her pheromones indicate she is receptive, although this may take several weeks. This is called premating protection. The male's purpose is to prevent any other males from approaching the female, but may also help protect her during risky behavior.
When they are disturbed enough, their anemones eject sticky threads called anemones, which provide additional protection.
Cartilage fish:
These are sharks and rays whose skeletons are made of cartilage rather than bone.
Two species of cat sharks are found in Helford, the Bull Hass or Great Cat Shark and the Lesser Cat Shark (formerly known as the Dogfish).
Bull Huss can reach lengths of up to 1.6 m, but both species are harmless and feed on molluscs, crabs and the occasional small fish. The female lays eggs, called mermaid purses, which hatch approximately 6 to 8 months later. The nearby Fal Estuary is a nationally important Bull Huss nursery.
Their common flat cousin is the spinyback ray. Their females also lay eggs, which technically makes them skates and not skates! Males are easily identified by a pair of clasps, which are modified ventral fins used for mating. Their coloration varies greatly, so the best way to distinguish them from other rays is by the barbed lines on their back and tail, which give them their common name. When resting, they tend to bury themselves lightly to improve camouflage. They can quickly rotate 180 degrees by wagging their tails. When there is no need to rush, females will “walk” using their pelvic fins, but once they use their pectoral fins or “wings” they can swim very quickly if necessary.
Chris Lewis
December 2025
Join our Helford River Cruise Depart from the Budock Vean Hotel in Helford and bring your snorkeling gear, you never know what you might see!
