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1 . Biological safety issues. Dan Minchin Marine Organism Investigations, Ireland. Coastal Research and Planning Institute, Klaipeda, Lithuania. September/November 2013. OUTLINE. What stings or bites Parasites, diseases and toxins Impacts on Fisheries and Aquaculture.
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1. Biological safety issues Dan Minchin Marine Organism Investigations, Ireland Coastal Research and Planning Institute, Klaipeda, Lithuania. September/November 2013
OUTLINE • What stings or bites • Parasites, diseases and toxins • Impacts on Fisheries and Aquaculture
Stinging medusae • Occur in Indosesia • and Australia • Often there are • fatalities • Difficult to see in the • water
Often fatal • Suits prevent the nematocysts from penetrating through to the dermis and releasing their toxin
Irukandji stings • Venom life threatening • Vinegar over wound, remove tentacles • Need to know Cardio-pulmonary resuscitation
Variable impacts from medusae • The luminous medusa Pelagia noctiluca occurs • worldwide • It does not have a settled stage • Can be found in tropical to cool temperate conditions • Often inflicts stings on swimmers
Stinging siphonophores Apolemiauvaria
Some sea slugs carry the nematocysts from the coelentrates they feed upon • The neustonicGlaucus feeds on the Portugese-man-of war and retains its most potent nematocysts
Stinging corals • Some corals have nematocycts long enough to penetrate human skin • Avoid touching them as they can give an unpleasant sting Fire coral
Polychaete spines (setae) • Toxic worms are often colourful • Frequently occur in shallows • Toxic setae which can also act as an irritant
Spines • Almost all catfish have spines and some can cause painful wounds • Mainly occurring in South America
Spines • Most perch-like fish have spines some are venomous
Spines: the weever fish • Occur in coarse sands • Easily stepped upon • Very painful • Heat treatment of wound
The stonefish • Highly camoflaged • Several deaths a year • In Indo-Pacific • Occurs on reefs • May be found in shallows and is often walked upon
Spines • Sting rays occur in shallows and are often stood upon • Tail can lasso a limb and draw it onto spine
Spines in some aquarium fish • Venomous • Several species in Indo-Pacific • Recently arrived to the Atlantic • It is an avid predator
Surgeon fish blades • Cuts can become infected • Some are venomous • Do not threaten them and you are alright
So you thought that the water was safe The cadira: a small catfish Ah! That’s Guinness
Spines • Urchins often appear in clusters • Some have hollow toxic spines
Harpooning snail • Conus geographus • Known to cause fatalities • A special way to pick them up
How to lift a cone shell Avoid the harpoon by holding the top end Do not store in your bathing trunks!
Crown of thorns starfish • Spines can penetrate skin • Venom causes pain, swelling and numbness • Wounds also easily infected • Effects may last some months
Venomous sea-snakes • These occur in the Indo-Pacific but have rarely been known to enter the Atlantic • One bite from some species is sufficient to result in death • Some are thigmotactic • Toxin can affect the nervous system and prevent blood from clotting
Tide-pool mollusc • Each year the venom from this octopus kills several people • It occurs in the tidepools and on account of its bright colours it is often removed by hand
Teeth • Teeth are well advanced in pisciverous fishes • Some can lance (many deep-water fishes) others shear (piranha, sharks)
Piranha • Occur in South America • Highest risk in dry season, in wet season not usually a problem as food plentiful • Piranhas hunt by day: • Don’t swim with a cut • Be slow and deliberate • don’t splash • Create a diversion with • an animal carcass
Puffer fish • This has a toxic flesh (tetradontotoxin) • It can also result in significant bites as it can break off coral with its mouth
Great Pacific octopus While some people have been bitten and died they are usually harmless and can be ‘cuddled’
Shark attack • Many myths
Reduce the risk of shark attack • Swim in a group • Do not go far offshore • Avoid swimming at night, dusk or dawn • Do not enter if menustrating or bleeding • Don’t wear shiny jewelery, watch • Don’t enter areas with sewage • Don’t enter where there are sharks • Avoid coloured clothing (yellow) or have an uneven tan • Don’t splash too much • Keep clear of sandbars and drop-offs • Avoid immersion near seal colonies
Ciguatera • Condition found in tropical reef fishes • Can be found in fish or their predators • Toxins produced by dinoflagellates • Can not be prevented by cooking and symptoms can be transmitted from sexual intercourse
Parasites • Can accumulate in filter feeding molluscs • Occurs in contaminated water from farm animals and human sewage • Cysts can remain in tissue • Might result in cryptosporidiosis if eaten
PSP • Caused by a dinoflagellate • Periodic blooms • Usually in bays and inlets • The dinoflagellate may be distributed by ships ballast water or molusc stock transmissions • Cats are susceptible to PSP Alexandriumtamarense
ASP • Due to demoic acid produced by a diatoms Pseudo-nitzschiaand Nitzschiaspecies • A neurotoxin causing short term memory loss, brain damage, sometimes fatal
Impacts on using living resources • Pelagic coelentrates can compromise fin-fish farming • Shellfish toxins can affect mollusc production • Sewage discharges can limit production • Ciguatera can affect local inshore fisheries • Cultured species usually do not bite or sting