Many marine animals are potentially hazardous to divers. Although only a few are serious physical threats, many lesser hazards can seriously impair a diving program by reducing the diver's effectiveness. The material that follows introduces some of these hazards. For convenience, hazardous marine animals have been artificially classified here as: a) those that passively lacerate or abrade; b) those that sting; c) those that bite; and d) those that shock. This classification has limitations: the categories obviously overlap, and although most hazardous species fall naturally into one or another of these categories, some can be placed only arbitrarily. 15.1 MARINE ANIMALS THAT PASSIVELY LACERATE OR ABRADE non-venomous The animals described here are forms that do not strike out at divers, as do some of those discussed in subsequent paragraphs. Nevertheless, herein lie the major hazards to the working diver, even though divers must bring themselves into contact with these creatures in order to sustain injury. Because his skin has been softened by the water, the diver is especially vulnerable to the many sharp edges and abrasive surfaces that are present in the sea, especially on certain hard-bodies. bottom-dwelling animals like barnacles, mussels and corals (Figure 15-1). A careless diver will almost certainly injure himself when working among such creatures, especially if unprotected by a diving suit, as often is the case in warmer water. On any one occasion, injuries of this sort rarely are serious; however, wounds resist healing when continually exposed to water, and in time a careless individual may accumulate an array of ulcerated *First aid treatment for injuries caused by marine organisms is contained in Section 17. sores that incapacitates him as a diver. To compound the problem, there seems to be a relatively high incidence of secondary infection in such wounds. Thus, long-term diving programs can be crippled by failure to take special care to avoid these minor injuries. 15.2 MARINE ANIMALS THAT STING Many marine animals can inflict venomous wounds. These diverse forms are considered together in this section no matter whether the venom is introduced into the victim by spines on the body, by stinging cells, or by fangs in the mouth. The toxicity of the venom, as well as the amount of venom introduced, varies from one species to another, and sometimes between individuals of a single species. Furthermore, humans can differ from one another in their sensitivity to a given venom. The reactions of humans to the stings of marine animals can range from no noticeable reaction at all, to mild irritations, to rapid death. It is wise to avoid all marine organisms of types known to be venomous; however, occasional contact is inevitable for even the most cautious of experienced divers. 15.2.1 Sea Urchins Generally the most troublesome animals for divers on tropical reefs are venomous sea urchins (Figure 15-2). This is especially true after dark, when visibility is reduced and many of the noxious sea urchins are more exposed than in daylight. Sea urchins may also be a problem in temperate waters, where they lack the venomous spines of the tropical species. Most difficulties with venomous sea urchins result from accidental contact with certain longspined species. The smaller secondary spines that lie among the larger primary spines do the most damage: apart from their venom, these spines invariably break off in the wound, and, being brittle, frequently cannot be completely removed. Gloves and protective clothing are some protection during minor brushes with these animals, but do not help much when a diver strikes forcibly against them. To avoid painful injury when working close among venomous sea urchins, one can only remain alert to avoid contact. Reportedly some of the short-spined tropical urchins are hazardous, owing to tiny pincer-like organs, called pedicellariae, that occur among the spines. Although some pedicellariae contain a potent venom, they are very small structures that probably do not threaten divers who incidentally come into contact with the urchins that carry them. One can handle these urchins without concern for pedicellariae by wearing gloves. 15.2.2 Jellyfishes Grouped here are a variety of organisms that mostly drift or swim slowly at the water's surface or at middepths. They have gelatinous, semitransparent bodies, often bell-shaped, from which trail tentacles armed with stinging cells, called nematocysts. Figure 15-2 Sea Urchins |