Shell fish in August.... Myth and reason?

[Jolyon]

Recently was camping with the family in Cornwall and found a wonderfull Mussel bed (no out-lets near by!), some sanfire and wild Garlic- yum yum... if only White wine grew near the sea......
I had it drummed into me that you can't eat shelfish in a month without an 'r' in it. But also had a memory this was really about Oysters not all shell fish.
As it was we waited untill after the new moon (not for religous reasons...;-) as figured if they were going to spawn it would be about then and then had a slap up meal... All still alive with no side effects.
Were we just lucky? Did the hot weather earlier in the year mean that August was safe? Why is May-Aug not safe? what is 'bad' about a sporing shell fish?.

Anyone?

 

[Bardster]

Its also to do with algae blooms. Hot summer months you are more likely to get algae blooms off and in shore. These are toxic and the filter feeders suck them up and pass them on to you when you eat the shellfish.

"Red tide is a toxic algal bloom of red-brown dinoflagellates that occurs after a population explosion due to specific water conditions. The blooms are usually seen when warm surface temperatures, low salinity, high nutrient content, and calm waters are present. Warm, sunny days after much rain often create these conditions, Sometimes the bloom can discolor the water, giving the phenomenon its name.

The shellfish affected by the toxins usually do not appear different. The toxin also has no taste or smell. So the safest method to avoid toxicity during red bloom is to avoid eating certain seafood, specifically molluscs and shellfish.


Read more at Suite101: Paralytic Shellfish Poisoning and Toxic Algal Bloom http://neurologicalillness.suite101.com/article.cfm/paralytic-shellfish-poisoning-and-toxic-algal-bloom#ixzz0x2mrrT00"

 

[Tor helge]

Hi
I`ve heard it up here too.
But it refers to fish only (or more correct, the Cod), as people up here didn`t eat shellfish earlier (it was used as bait).
The reason for this is that the water is warmer and it is said to lessen the quality of the fish (the meat is softer and so on). I must admit that I can`t taste any difference when eating fish in summer.
I think the reason for this "superstition" is that it is more likely that shellfish, being filter feeders, is poisenous in summer than in colder months, due to the algae growth.

Too slow typing it seems. Beaten by Bardster .

Tor

 

[BarryG]

How do you know when there is a red tide or not? Especially if you were out in the sticks, disconnected from the media.
Rely on the old poem, avoid foraging during the summer, or are there other natural signs?

 

[Jolyon]

How do you know when there is a red tide or not? Especially if you were out in the sticks, disconnected from the media.
Rely on the old poem, avoid foraging during the summer, or are there other natural signs?

Kinda my point...;-) seeing a lovely big bed of mussels and not being able to touch it for 3rd of the year seems a little well.... extreme?

Is it only dangerous if there is a full bloom on? i.e. visable? If not is there a simple test to see what the alge load is in the water?

 

[Whittler Kev]

On a cookery programme (Country Cottage?) the local Cornish fishermen also said it was so the bed and stock could recover. Where people didn't adhere to it there are no longer any left as they were over fished

 

[nitrambur]

I thought it was only oysters and a myth anyway, something to do with them looking odd when they're in their "breeding season"

 

[trixx]

It's a myth, probably from the days when transport was less reliable and perishable shellfish were the first things to start going bad.

No problem at all eating any shellfish during the summer months if it's fresh.

 

[BarryG]

Im no exert, but I have seen the occasional TV programme seemingly confirming the danger of Dinoflagellate algae, and it is supposed to cause paralysis in people that eat filter feeding shell fish such as mussels etc. Grazing molluscs such as limpets are safer.

 

[gregorach]

It's a myth, probably from the days when transport was less reliable and perishable shellfish were the first things to start going bad.

No problem at all eating any shellfish during the summer months if it's fresh.

There are four kinds of poisoning you can get from shellfish (paralytic, neurotoxic, diarrheal, and amnesic), all of which are caused by toxins produced by algae or cyanobacteria during the summer months, which are then concentrated by filter feeders such as bivalves. Two of them (paralytic and amnesic) are potentially deadly. The Scottish Marine Research Laboratory (and, I presume, whichever agency deals with this sort of thing the rest of the country) regularly takes samples from all commercial shellfish fisheries to test for the presence of these toxins, and will close certain areas if levels are dangerous. Such closures happen every summer somewhere or other. You cannot identify contaminated areas or shellfish without laboratory testing.

And people think mushrooms are dangerous...

 

[Grooveski]

I've heard that the 'r' in the month system isn't all it's cracked up to be. Apparently out the western isles the gulf stream can keep the temps up in the right range until october or even later.

I knew an auld shepherd who swore by popping a silver thrupenny into a clam the moment they opened. He burned out ticks too - bloody wonder he made it into his nineties.

 

[BarryG]

There are four kinds of poisoning you can get from shellfish (paralytic, neurotoxic, diarrheal, and amnesic), all of which are caused by toxins produced by algae or cyanobacteria during the summer months, which are then concentrated by filter feeders such as bivalves. Two of them (paralytic and amnesic) are potentially deadly. The Scottish Marine Research Laboratory (and, I presume, whichever agency deals with this sort of thing the rest of the country) regularly takes samples from all commercial shellfish fisheries to test for the presence of these toxins, and will close certain areas if levels are dangerous. Such closures happen every summer somewhere or other. You cannot identify contaminated areas or shellfish without laboratory testing.

And people think mushrooms are dangerous...

It makes you wonder how our Neolithic coast hugging ancestors got away with it. Perhaps it wasnt as common then? Less nitrates etc.

 

[gregorach]

It makes you wonder how our Neolithic coast hugging ancestors got away with it. Perhaps it wasnt as common then? Less nitrates etc.

That may well be part of it, but I suspect the most likely answer is that quite a lot of them probably didn't, at least until they learned better. Where do you imagine the advice to avoid shellfish in the summer came from in the first place?

 

[Jolyon]

On a cookery programme (Country Cottage?) the local Cornish fishermen also said it was so the bed and stock could recover. Where people didn't adhere to it there are no longer any left as they were over fished

Yep i heard that one as well, althuogh the fishermen still had a go! seemed it was just a way of keeping out the summer tourist bloom..;-)

 

[Jolyon]

So advice seems to be don't forage bivalves.... or always test them on the youngest family member first? ;-)

 

[gregorach]

You should be fine in the early months of the year. I know that there's a page on the web somewhere detailing the safety of all the harvesting areas around the UK which is continually updated during the summer (if not all year) but I'm having dreadful internet issues today, so I can't find it - but that's where I'd check if I were planning on doing any shellfish foraging.

 

[Jolyon]

Thanks Gregorach,
If you ever find it would love the link.....

 

[gregorach]

OK, found some info from the FSA. Start here: Shellfish monitoring. Unfortunately, it only seems to have data for Scotland, Wales, and Northern Ireland...

I know I've seen the data presented in a more usable form somewhere else...

 

[trixx]

The Scottish Marine Research Laboratory (and, I presume, whichever agency deals with this sort of thing the rest of the country) regularly takes samples from all commercial shellfish fisheries to test for the presence of these toxins, and will close certain areas if levels are dangerous.

Correct. Round here it's the local authority that has responsibility for testing commercial shellfish fisheries - mussel farms, mostly.

And you are right, they would close areas or suspend landings from any area that posed a potential danger. If there were a more general problem with sea areas, you can be sure it would be headline news, because it would severely affect the commercial fisheries.

However, I can tell you that there is no general problem with eating shellfish in the summer months and that you have the dangers completely and utterly out of perspective. A bit like telling people they shouldn't eat tinned food because they may get botulism.

Round here at the moment people are eating freshly-caught scallops, mussels, razorfish - all the commonly eaten bivalves - by the ton, with no problems. Likewise shellfish such as crabs, lobsters and prawns. So I stand by my previous statement, it's an absolute myth that shellfish shouldn't be eaten in the summer months. How do I know? I'm a commercial shellfish fisherman and I haven't noticed my customers dropping dead, so I'd suggest that my practical experience trumps your googling in this instance.

 

[Jolyon]

Thanks Trixx,

So basically if it is a nice tidal area with no obvious outlets and no recent heavy rain that would flood out 'occasional' outlets, the sea is crystal clear and it is a well established bed ( i.e. a million plus mussels or all shapes and sizes) i should be safe?

I always assumed human mess being a bigger risk than red sea?

It is a common sense issue?....

As is was we picked a couple and ate them...... and then after 24hrs went back for more!

On an aside is spawning ever an issue? or is it just agea blooms?