Dangerous Recreational Activity

Drowning isn’t the only danger in water - some aquatic animals can be deadly. The scuba diver who dies underwater poses a difficult diagnostic dilemma for investigating authorities and pathologists. Barotrauma caused by the failure of a gasfilled body cavity to equalize its internal pressure with changes in the ambient pressure is another cause of death. Investigation should be thorough and follow a standardized outline. This investigation should include the victim’s past medical and social history, dive profile, a detailed history of the terminal event and resuscitation efforts, environmental conditions, examination of the diving equipment and finally the autopsy.

What is wrong with recreational scuba diver databases?

This commentary draws attention to the challenges for researchers in accessing and using recreational scuba diver training agency and other dive industry databases. These challenges may lead to biased conclusions as to the size and nature of scuba diver populations, falsely identify the diver in specific sectors, distort potentials for scuba diving tourism and incorrectly ascertain what exactly motivates diver travel preferences. The commentary aims to raise awareness of the challenges of gaining access to meaningful recreational scuba diver data and a need to exercise caution when using available scuba diving industry databases.

UNDERSTANDING THE VARIABLES THAT INFLUENCE SCUBA DIVER BEHAVIOUR ON CORAL REEFS IN SEYCHELLES

Determining the fundamental causes of scuba diver contact with coral reefs is vitally important for the marine tourism sector. This information can provide management authorities and dive operators with methods to promote and demonstrate sustainable dive practices in order to reduce physical interaction by divers on coral reefs. This study provides an insight into what variables influence physical contact by scuba divers on coral reefs around Praslin Island, Seychelles. Underwater behaviour was studied from 205 divers to identify what factors significantly influence contacts on coral reefs at dive sites. Male divers contacted the reef twice as much as female ones (0.25±0.04 versus 0.12±0.02 contacts min-1). Photographers contacted the reef significantly more than those divers without cameras (0.30±0.06 versus 0.10±0.02 contacts min-1), as did diving at midday versus in the morning (0.46±0.13versus 0.16±0.02 contacts min-1). Diver age had a significant effect on contact rates, with the 41-50 age category responsible for the highest amount contacts (0.31±0.07 contacts min-1). Dive operators need to be extra vigilant with these high-risk divers, utilising a combination of damage prevention methods for camera users, providing closer supervision for older divers and reminding divers about eco-friendly dive techniques who are completing more than one dive that day.

ON REGISTERING RESPIRATORY-ASSOCIATED NOISES OF SCUBA-DIVER IN SHALLOW WATER WITH BOTTOM–MOUNTED HYDROPHONES

Предотвращение несанкционированного проникновения легководолазов в прибрежные мелководные акватории остается актуальной задачей. Для диапазона частот ниже 100 Гц, характерного для шумов, связанных с дыханием водолаза-аквалангиста, существенная часть регистрируемых размещенными у дна гидрофонами может быть соотнесена с сейсмоакустической составляющей волны, бегущей по осадочному чехлу дна и/или тонкому придонному водному слою акватории. Дистанции, на которых удается идентифицировать низкочастотные дыхательные шумы водолаза-аквалангиста, достигают 180–220 м. Prevention of scuba-diver trespassing shallow-water littoral areas is considered as actual. In frequency range below 100 Hz, characteristic for respiratory- associated noise of scuba-divers, a significant part of the signal registered with bottom-mounted hydrophones, may be connected to the seismoacoustic component of the wave, travelling through the sedimentary bed and/or through a thin water layer above it. An identification of low-frequency respiratory-associated noises of scuba-diver in shallow-water areas is achieved at distances up to 180–220 м.

Cerebral Gas Embolism in the Course of Mildly Symptomatic Pulmonary Barotrauma in a Scuba Diver

The paper presents a case of pulmonary barotrauma in a scuba diver. Swallowing water and respiratory arrest during the ascent caused the trauma. Symptoms from the respiratory system (including the Behnke’s symptom) appeared several minutes after the completion of the dive and were not severe. However, symptoms from the peripheral nervous system, which appeared later, increased rapidly until the seizure episode and loss of consciousness. Hyperbaric treatment was applied in a decompression chamber on board the ship from which the dive was conducted. The treatment resulted in complete remission of symptoms without any consequences.