Major Points:

1. Most marine venoms are heat labile proteins.  Hot water (110-115℉ for 20-30min) immersion will be effective in most cases.

2. Anti-venoms exist for severe jellyfish, fish, and sea snake cases.

3. Treatment is largely supportive with hemodynamic or respiratory support in severe cases, analgesia (nerve blocks work well!), wound cleaning and fb removal, infection prophylaxis for dirty wounds, and trauma resuscitation for penetrating injuries.

Potentially fatal:LOOK DON”T TOUCH!

• Sea snake-⅕ bites cause envenomation, neurotoxin and myotoxin, give antivenom if severe.
• Cone shell-potent neurotoxin, no anti-venom.  
• Blue ringed octopus-tetrodotoxin, flaccid paralysis.
• Jellyfish-severe envenomations from box jellyfish, Portuguese Man-o-war.  Some indo-pacific species cause Irukandji syndrome (catecholamine surge, cardiac injury).

Rarely if ever fatal but tremendously painful:

• Stingrays-fatalities from penetrating trauma
• Venomous fish-stonefish, lionfish, weever fish, scorpion fish.  Antivenom. 
• Sea urchins-painful.  Hot water immersion, remove spines.  

Nuisance envenomations:

• Sponges, fire coral, hydroids, sea bather’s eruption, sea cucumbers.

More on Jellies: On the Beach or Boat (these measures will suffice for most minor stings):

• Can irrigate with sea water, no fresh water rinse! Hypotonicity can discharge nematocysts.
• Prevent patient from thrashing, attempting to rub tentacles off, this will cause further stings.
• Scrape attached tentacles/nematocysts with credit card or knife. 
• Vinegar is useful for Indo-Pacific box jellyfish, Chironex fleckeri, otherwise stick to hot water.
• Manage ABC’s and analgesia as available
• In the ED:
• ABC’s, support as necessary, analgesia, anti-venom in severe cases
• Limited data, Mg may be helpful in cardiac arrest
• Alpha blockers useful in Irukandji syndrome 

Some common marine poisons:

• Ciguatera-Dinoflagellate toxin consumed by and stored in reef fish, moves up food chain to snapper, grouper, barracuda, amberjack, eventually to humans.  Causes N/V, abd pain, headache, perioral paresthesia/pain, temperature dysesthesia.  Supportive care.
• Scombroid-from eating pelagic fish.  i.e. tuna, mackerel, wahoo, mahi. histidine converted to histamine in improperly stored fish, not avoided with cooking, similar to allergic reaction, profound flushing, itching, treat with antihistamines.  
• Puffer Fish (fugu)-Delicacy in Japan, tetrodotoxin similar to that of blue ringed octopus, flaccid paralysis in severe cases.