DESCENDING THE EAST SIDE OF BAJO DE DENTRO, the thermocline at 10m bites with a vengeance, from 22C to 18C over just a few metres. The shallow warm water is beautifully clear but some frisky marine organism below the thermocline is filling the deeper water with long globs of stringy snot plankton. Its the sort of thing that lasts only days, but it happens to coincide with my trip.
     Still, I have a gut feeling that this will be a worthwhile dive. Reaching 25m, dive guide Alfredo turns south along the wall. I cut the corner and skirt ahead for good camera angles, in and out of a small cave then deeper, round the south end of the reef.
     Visibility is good despite the plankton, yet the effect is like swimming through cobwebs. Even the forest of red gorgonians near the 40m mark looks more like a movie set over-decorated for a haunted-house scene.
     I am unfamiliar with some of the Mediterranean fish. Clouds of orange anthias and grey damselfish are easy and I recognise grouper, bream, saupe and most of the wrasse, yet a large grey fish with a yellow splodge is new to me.
     As so often happens with late afternoon dives, everything clicks. Its the sunlight level, the angle of the lighting, the waves, the current, the fish behaviour - and perhaps Im beginning to chill out a bit by this time of day.
     I had already dived at the other end of Bajo de Dentro and at the Segundo Caibezo of Bajo de Piles, which I presume means the second pinnacle of the reef. Both were quite nice, but I hadnt begun to get excited until towards the end of the dive on Bajo de Piles, when I finally managed to get a shoal of barracuda to co-operate.
     Three times before I had failed to get close enough, and departed for five minutes to let them settle back into position above a saddle in the reef. Each time the encounter had been close enough to get excited about, but not close enough for photographs. The same thing occurred with some fair-sized grouper and a selection of eagle rays. Then, finally, the barracuda had accepted me and my camera got its reward.
     I had originally travelled to Murcia in Spain in April, for a long weekend, but diving had been curtailed by heavy seas. This had left me to enjoy larger quantities of red wine than if I had been diving, visit an art exhibition in the city of Murcia, see a Holland submarine preserved on the seafront at Cartagena and go sailing.
     Under water, I had seen enough to convince me that it would be worth coming back at summers end, for the better diving conditions I was now enjoying.

thermal reservoir
The reef system of the Islas Hormigas extends several kilometres out to sea from the point at Cabo de Palos, a tight, right-angled corner in the coastline south of Alicante and east of Almeria. The reefs and islands are a protected marine reserve, with the Isla Hormigas and the outermost reef, Bajo de Fuera, no-go areas.
     The other significant marine feature is Mar Menor, an enormous saltwater lagoon just north of Cabo de Palos. It is separated from the sea by La Manga, a wide sandy beach about 15 miles long, its southern two-thirds a long strip of hotels, villas and marinas, and the rest a nature reserve with old saltpans and flocks of pink flamingos.
     Mar Menor is only a few metres deep and no one dives in it, though it provides warm sheltered water for other watersports.
     Currents sweeping round Cabo de Palos and across the reefs provide the environmental conditions for prolific fish life, while the thermal reservoir of Mar Menor gives the region its own micro-climate.
     And with shallow reefs running well out to sea, there have been many shipwrecks, particularly on the outermost Bajo de Fuera, now in the no-go part of the marine reserve.
     I dive the wreck of the Isla Gomera, just over a mile out from the Club de Buceo Islas Hormigas in Cabo de Palos. The wreck is outside the marine reserve, so accessible to suitably experienced divers.
     We arrive to find a lone spearfisherman in his boat above the wreck. We wait a few minutes while he free-dives for his lunch. He soon gives up, and leaves the area safe for divers.
     I cant see the wreck from the surface, but the outline is distinguishable through the plankton as I break the thermocline and get beneath the shoal of fish already gathered in the shade of our boat. The buoy line is attached to the bow, the shallowest part of the wreck at just past 30m.
     The Isla Gomera foundered in 1946 when its cargo of oranges shifted in a storm. It is referred to locally as Naranjito, after the Spanish naranja, or orange. With nothing worth the attention of commercial salvage, and deep enough not to obstruct shipping, the wreck is beautifully intact and upright.
     I swim rapidly for the stern, the deepest part of the wreck at 42m. I spend some time beneath the propeller and rudder, then work back through the engine room at the stern, intact triple-expansion engine and single boiler. There is a single aft hold, a central wheelhouse and then a single forward hold before the raised forecastle.

stunning viz
For another wreck dive I join Ribera Diving at Santiago de la Ribera, a resort town at the opposite end and inside Mar Menor.
     As the large RIB screams across Mar Menor, I can see the blurred seabed below. We head out to sea, past the easy dive sites at Isla Grosa and Farallon. At this end of Mar Menor there are apparently no good intermediate dives, only shallow sites around the islands and the deeper offshore wrecks.
     It is another 15 minutes to El Carbonero, the name again probably derived from its cargo - of coal. Visibility is stunning. I can see the outline of the wreck 40m below from the surface.
     The anchor has caught a winch forward of the base of the funnel at 38m. Just aft, I drop into the engine room through one of the open ventilator hatches and head to the stern, past the top of a nicely preserved triple-expansion steam engine.
     The aft pair of holds are well broken, but enough is left to hold the wreck together, with a propshaft tunnel running along the keel. Beneath the stern at 44m, the prop has only one blade left, pointing straight up. An old fishing net is draped from the stern above, now bunched up and with enough marine life growing on it to form part of the scenery. Above is an empty gun platform, but no gun.
     The ship is thought to have been torpedoed by a U-boat in World War One. Merchant ships would hug the sanctuary of the neutral Spanish coastline and submarines would catch them as they came further offshore to skirt Bajo de Fuera.
     Apparently some divers were caught lifting ammunition from the gun, and the authorities have threatened to ban diving on this wreck.
     The forward holds are more intact, though all but a few lumps of coal have been salvaged. I just have time to make it to the skeleton of the forecastle and see that both anchors are gone before my 20 minutes are up. Ascending through the thermocline to make my stops in warmer water is a blessing.
     The Italian passenger liner Sirio, the most famous wreck in these parts, used to be diveable but is now in the no-go part of the reef.
     Local dive centres are hoping for a permit system to allow recreational diving on Bajo de Fuera to resume. But the story and potential for diving are too good to miss, so I ask Estaci—n N‡utica if it can get me permission to dive.
     Sirio was built in Glasgow in 1883 and sailed in the Italian merchant fleet. It usually worked the same route from Genoa, carrying immigrants to the South American colonies. Its official complement was 127 crew and 1300 passengers.
     On 4 August 1906 the sea was calm and the weather clear, but Sirio steamed into Bajo de Fuera at 17 knots, tearing out the keel to leave the bow out of the water and the stern and first-class cabins pushed under. As water filled the engine room, the boilers exploded.
     The passengers and crew panicked. There were insufficient lifeboats and few could swim. Captain José Piccone and his senior officers emptied the safe and jumped into one of the first boats - Piccone would later be jailed for this act.
     Men fought with knives and guns for space in the boats, or on the raised bow. Boats were capsized by too many frantic passengers jumping aboard or fighting for space.
     A mother being rowed to shore saw her three children clinging to a mast as it went under. Popular singer Lola Millanes, trapped inside the stern, pleaded with those outside to shoot her through a porthole before she drowned. The Bishop of Sao Paulo in Brazil went down with the ship as he was blessing the drowning victims.
     Vessels from Cabo de Palos managed to save 440 lives. The official manifest was 820 passengers plus crew, so officially 507 lives were lost. But the Sirios captain, as was his way, had called at Alcira to load illegal passengers into the holds at 100 pesetas each, so the death toll was considerably higher. Locals call Sirio the Titanic of the Mediterranean, though it sank six years before the Titanic.

On my last day at Mar Menor, with a flat-calm sea, minimal breeze and clear blue sky, the permit arrives. Weather reports for the rest of the coast indicate storms and torrential rain, so I bless the micro-climate.
     As we pass the lighthouse on Isla Hormigas and get into the right area, its easy to see how Sirio ran foul of Bajo de Fuera. In a calm sea there is no groundswell or breaking waves to warn of a pinnacle which comes to within 3m of the surface.
     We descend the steep reef to the main stern section of the wreck. The Sirio had wedged across the reef before breaking, the bow third falling on the opposite side to the stern two-thirds.
     We are back in the stringy plankton, though its far clearer than further inshore. I curse as my camera port fogs over. Having got warm on the boat-ride out, the small amount of humidity in the air has condensed on the inside of the now-chilled glass. It will eventually clear, but will this be within the limited bottom-time available on a 50-60m dive
     I follow the wreck from the boilers towards the stern. It is collapsed against the rock, sections of engine crank and propshaft poking through the hull. At 60m, all I can see is wreckage continuing deeper. Without helium, I turn back and concentrate on photographing my return route, now the fogging has cleared.
     Above the thermocline and in sparkling, clear warm water, we swim round the top of the reef while decompressing. Huge shoals of saupe, bream and barracuda can be seen on the opposite upcurrent side. Looking down, I see scraps of wreckage, the crankshaft of a steam engine, odd bits of metal and a winch, but too deep for this late in the dive.
     A couple of hours later, we dive the other side of the rock. The barracuda part as we work deeper along the reef.
     Passing odd scraps again, we eventually come to a cleanly broken cross-section of wreck at 45m. Its a nice piece of wreckage, but unlikely to be part of Sirio. It looks more like a freighter and, furthermore, is a stern complete with propeller and rudder!
     At least two other wrecks rest broken here - the steamship North America, which went down in 1883, and the Minerva from 1899. Others have been holed and drifted off to sink elsewhere. But even without the wrecks, Bajo de Fuera is a stunning dive. If the permits are ever sorted out, I could happily spend a week diving this rock.

pavement café culture
     From the Mar Menor region, I travel down the coast to Aguilas. The inland route by autopista takes less than two hours but my driver follows nacional roads between coastal towns. It takes longer, but provides some interesting scenery.
     Fertile valleys and plains are crowded with fruit and vegetable farms, mile after mile of polythene greenhouse. Derelict windmills line the banks of irrigation channels, like losers in a jousting contest with Don Quixote, superseded by more modern irrigation systems.
     We skirt Cartagena, a major port since Roman times, before climbing into the coastal mountain range for some stark and dramatic landscapes. We pass abandoned mine workings, tall chimneys reminiscent of Cornwall, before descending to connect with the autopista for the final few miles into Aguilas.
     The local population is only 30,000, yet peak season sees as many as 200,000 visitors, 80% of them Spanish. This is a tourist town with a very Spanish atmosphere. There is no heaving, drunken club scene or plethora of British pubs and fish and chips, only a thriving pavement café culture.
     The journey to Montoya by RIB takes about 15 minutes. We pass an old railway pier used to load iron ore to ships in the 1920s but now used by a fish farm. An old steam loco is displayed on the seafront.
     The dive site is marked by mooring buoys in the bay before Cabo Cope. Other boats are already tied on, at various stages of dropping and recovering divers. Pepe claims an empty buoy in the middle of the line.
     With negligible current, fixed moorings and calm surface conditions, standard practice is to drop kit lines over the side and leave the boat unattended. The kit lines are used to secure equipment when climbing aboard later.
     Many locals simply throw their kit in the water and jump in after it. When its hot this may be the most comfortable way to start a dive. With a camera to protect, I sit on the tube and roll in when I know that everything is firmly attached to me.
     We descend through warm clear water and an aggressive thermocline into colder water. The buoy line is bolted to a 3m-high reef at 30m.
     While settling down I observe a large black and white spotted nudibranch, but the main subject of this dive is not the rocky reef but three wooden fishing boats sunk as an artificial reef nearby. We strike out along a rope marking the route to the nearest boat, about 30m away. On a good day it would be visible from the reef, but today the cobweb plankton is about.
     The wooden boats are in various states of decay. The oldest is just a keel and a few timbers, the reef being as much the pile of rocks used to sink the boat as the timbers poking out from under them. The most recent boat is fairly intact and only a couple of years old, with just a few rotted planks and the paint gone, the rocks secured inside the hold.
     All are swarming with orange anthias and grey-brown damselfish. Large grouper glide across the deck and between timbers, not hiding but not volunteering to pose for portraits. This whole area is marine reserve.
     There are many eels, particularly on the more broken wreck, and morays and congers live in holes almost next door to each other. If it came to a fight over dinner, my cash would be on the congers.
     After a couple of hours chilling out on the terrace above the Club Estela dive centre, our second dive is at Isla del Fraile, named because its silhouette is reminiscent of a friars double-peaked hat.
     The mooring is in 8m on a mixed seabed of rocks and sea grass, leading off to a boulder slope to the south. The plankton in the deeper water seems less dense here.
     We work along the slope in the colder water, then back in the warmer shallows.
     There are no spectacular big scenes, so I busy myself with sea anemones, small corals and fish hiding under the rocks. The free-swimming fish seem to congregate annoyingly at the thermocline, where the oily effect of mixing water makes them appear constantly out of focus.
     Before going out for the evening, I scan the TV channels. I find a quiz programme thats instantly identifiable despite my limited Spanish. A semi-circle of contestants is presided over by a black-coated and bespectacled lady with a stroppy schoolmistress attitude. Losers are dismissed with a harsh Adios.

soft-focus madonna
Next morning we dive at Montoya again, followed by La Cueva de la Virgin, a reef closer in to Cabo Cope and nearer to the point.
     Here a small cave has a shrine built in its entrance, with painted and glazed tiles depicting a scene of Mary with baby. The image takes on a soft-focus feel where my camera port has misted slightly through the thermocline.
     Its a nice dive, greatly enhanced by more old wooden fishing boats sunk off the reef. The oldest is in a similar state to the oldest at Montoya, while the most recent retains a glossy sheen of white paint.
     None is big enough to make a single dive, yet travelling between them I can appreciate the progression of decay and the unique character of each wreck and its inhabitants.
     After lunch and siesta, I walk along the seafront and climb the hill, where an impressive castle presides over the bay. The town is filling up with weekend visitors. I find a nice little place in a hillside alleyway serving meats, cheeses and fishy bits on toast.

fussy mermaid
Pepe expects a busy Saturday, so we start an hour early. The wind has changed, pushing clean water in from the east. The plankton has cleared, as if a fussy mermaid has been spring-cleaning. The sun is out and everything sparkles against a clear blue background. I ask to go back to La Cueva de la Virgin to get some unfogged pictures.
     The dives so far at Aguilas have been pleasant, but nothing to rave about. This one is fantastic.
     A diver visiting from Madrid tells me that in these conditions, Montoya is even better. Should I repeat La Cueva de la Virgin for my last dive, or take a chance on similar conditions prevailing a third of a mile away
     I take the conservative course, partly because there is still one wreck at La Cueva de la Virgin I have not seen. And I am rewarded with another sparkling dive, with the added bonus of a sunfish stopping to be cleaned by wrasse above one of the wrecks.
     Later I ask the Madrid diver what Montoya had been like. He has experienced similar sparkling viz, and a dive as good as any he could remember.
     But then, I would have missed out on the sunfish.

the prop and remains of the rudder at 42m
at the bow of the Isla Gomera
looking along the beach from La Manga to the lighthouse at Cabo de Palos
a sunfish stops by for a clean-up at La Cueva de la Virgin, Aguilasbr
The mystery fish with the yellow splodge - any offers
triple-expansion steam engine on El Carbonero at Mar Menor
ascending from the broken hold to the stern
Hatch coaming on the Sirio
propeller shaft and tunnel
bream above a deckhouse, but is it part of the Sirio or one of the other wrecks
a diver explores inside the bow of El Carbonero
A solitary anchor, part of the artificial reef project at La Cueva de la Virgin
looking down on Aguilas from the castle
an anemone on the sand between wrecks


GETTING THERE: Scheduled flights with Iberia from Gatwick to Alicante, followed by transfer bus or rental car. La Manga and Aguilas are both just under two hours drive south from Alicante. Other options include budget flights with Buzz from Stansted to Murcia, and BMI from East Midlands to Murcia.
DIVING: Cabo de Palos - Club de Buceo Islas Hormigas, 0034 968 145530, www.islashormigas.com. Santiago de la Ribera - Ribera Diving, 0034 968 572162, e-mail: buceo@riberadiving.com. Aguilas - Club de Buceo Estela, 0034 968 448144, www.escueladebuceo.com.
ACCOMMODATION: Hotels from basic to luxury resort, apartments and villas.
COST: Murcia is a good place to combine diving with other activities, perhaps on a family holiday, but diehard divers may want to travel around to find enough variety for a solid week. Book a package holiday and a hire car and arrange diving directly with a dive centre. Ten boat dives including air costs from£125, with small supplements for some dives.
BEST TIME TO GO: Diving is available year round but conditions are best from May to September. Water temperature of 18-23°C in summer drops to 12°C in midwinter.
water temperature: Ranges from full UK suit in the winter to 5mm steamer or even less in the summer.
FURTHER INFORMATION: Spanish Tourist Board www.tourspain.es; Estación Náutica Mar Menor, 0034 968 574994, www.enmarmenor.net; Consorcio Aguilas Villa Náutica, www.consorcioaguilas.com.