The shallowest hulls on Gibraltar's artificial reef sit in roughly 7 metres of water. Most of the rest lie between 12 and 22 metres down. That one fact decides what snorkelling at Camp Bay really is, and almost nobody says it out loud: with a mask and fins you are a spectator above the reef usually billed as Europe's first, not a visitor inside it. That is not a reason to skip it. It is a reason to arrive expecting the right thing. What you get is a protected rocky shore carrying an unusual amount of life, sitting directly on top of a conservation experiment that has been running for over fifty years. The reef started as an argument about decline. In 1973 Eric Shaw, a local doctor and diver, proposed building an artificial reef because marine life in Gibraltar's southern waters was visibly thinning out. The first attempts failed in ways worth knowing about. Chained tyres were swept away or buried by sand. Benthic stones did no better and cost more. What worked was hulls. Two barges donated by Gibunco went down in Camp Bay in 1974, and [that is generally described as the first artificial reef built in Europe](https://en.wikipedia.org/wiki/Gibraltar_Artificial_Reef). A 65 ton wooden boat called True Joy followed in 2006. The Government's own biodiversity page dates the programme to 1975 and records that [over 30 vessels have been intentionally sunk](https://thinkinggreen.gov.gi/biodiversity/marine) for reef creation since. Nothing we found resolves that one year gap, so read 1973 as the proposal and 1974 or 1975 as the first sinking, and treat anyone quoting a single confident date with suspicion. The principle is simple enough. A flat sand bottom offers nothing to hold on to and nowhere to hide. A hull, or a block with bars sticking out of it, creates vertical surface, shade and crevices, and juvenile fish and invertebrates use all three. Fifty years of that in one small bay is why the water here looks different from the water 200 metres along the coast. In 2013 the Government dropped about 70 concrete blocks with protruding metal bars into the bay, working separately from Shaw's trust. Spanish trawlermen said the bars destroyed their nets, Spain disputed that the blocks had been authorised in waters it recognised as Gibraltar's, and frontier queues lengthened sharply that summer. The blocks are still down there. We set out the wrecks, the permits and what the Second World War actually left on the seabed in our [guide to wreck diving in Gibraltar](/blog/scuba-diving-gibraltar-olterra-human-torpedo-wrecks). Here is the layout of the site, with the disagreement between published figures left in rather than smoothed over. Nobody has resurveyed these hulls recently and the numbers drift by several metres between listings. |Feature|Depth|How you reach it|Permit needed| |Intertidal rock and shallow reef|0 to 3 m|Mask and snorkel|None| |Shallowest barges of the reef|About 7 m|Breath hold, visible from the surface on a clear day|None| |Batty's Barge|12 m in one listing, 14 m in another|Scuba|Class F, or dive under a permitted operator| |The 482 cable layer, sunk August 1990|16 m in one listing, 17 m in another|Scuba|Class F, or dive under a permitted operator| |Sun Swale, a 195 ton tug sunk 16 March 2015|About 22 m|Scuba|Class F, or dive under a permitted operator| |SS Rosslyn, wrecked on the South Mole in 1916|About 23 m|Scuba, boat access|Class F, or dive under a permitted operator| Two things follow. A competent breath hold swimmer can reach the shallowest barges in calm water, and on a clear day their outline is readable from the surface. Everything people photograph, though, the encrusted plating and the conger tucked under a deck, is 12 metres or more down and needs a cylinder, and a cylinder needs a permit. So do not book expecting to swim through a wreck on a snorkel. Book expecting to swim over a reef. The second thing is genuinely good and the first will only disappoint you. This is where most snorkelling pages go vague. They do not have to. Gibraltar published a species list, and it is a better guide than any blog. The [conservation objectives for the Southern Waters of Gibraltar](https://www.gibraltar.gov.gi/new/sites/default/files/HMGoG_Documents/SWoG%20Conservation%20Objectives_FINAL_23.1.18.pdf) name the typical reef fish here: white seabream, common two banded seabream, salema porgy, black scorpionfish, moray eel, conger eel, cardinal fish, swallowtail seaperch, greater forkbeard, dusky grouper and ornate wrasse. Not all of that is realistic from the surface, and pretending otherwise is how expectations get wrecked. Grouper and conger keep to holes and deeper rock. Scorpionfish sit motionless on the bottom and you will swim over a dozen without registering one. What you will see repeatedly is seabream, salema porgy grazing in loose shoals, and ornate wrasse, which [ranges from the surface down to 50 metres](https://en.wikipedia.org/wiki/Ornate_wrasse), reaches about 25 cm, and changes sex from female