Aquanaria

Aquanaria

Sunday 11 October 2009

The He-She of the British Coast

The aquatic world is amazing and continually throws up amazing creatures and their habits. Maybe unlike humans many aquatic animals have had to adapt dramatically to their changing environment. Over many thousands of years species have evolved as their local environments have become overcrowded or food depleted. TV documentaries leave most people relating these odd adaptations to ugly looking deep sea species or the beauties of the coral reefs, however, one of my favourite British coastal species have evolved a great method that ensures successful yearly recruitment (with feeding this is what the majority of the animal kingdom live for).

The Gilthead Bream, commonly referred to as dorade, dorada or orata, is a relatively plain looking silver fish. It grows to about 8kg and can have a life span of about 12 years. When you see one in your local fishmongers take a look at its set of small sharp teeth that help it deal with its main diet of oysters and other bi-valves. As it is a fairly solitary species that lives in shallow insure waters it avoids the pressure of commercial fishing, but it is however one of the most successfully farmed Mediterranean species. Pretty plain in all, oh yes one other point, they are all born as males then turn into females when needed! Oh yes, not plain anymore. The Gilthead Bream is a protandrous hermaphrodite; they are born with the sexual characteristics of a male, but when they mature, after about 3 years (800grm-1kg), a proportion of the males, only the required number, revert from male to female and start producing ova so the successful cycle continues. As farmed Gilthead Bream are usually harvested at sizes between 4-800grms it is very rare to see a mature specimen, however, I have a couple of times experienced boxes of sexually mature males. The size of milt production within a roundfish is much smaller than ova production within females. The Gilthead Bream, therefore, lends itself perfectly to cultivation.

As a point of note the Black Sea Bream, probably the most commonly seen wild bream on an English fishmonger’s slab, offers the complete opposite; they are protogynous hermaphrodites starting life as females then reverting to males.

2 comments:

  1. you don't mention any taste/texture differences between wild and farmed gilt head bream. I always look out for wild but enjoyed a farmed bream at The Swan in Chiswick recently. Not sure I could tell the difference unless eating the 2 types side by side.

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  2. A very good point. The farmed fish, when filleted, always appear a little oilier to the touch as you would expect from cultivated fish. The farmed are also a little firmer as they have not undertaken sexually maturity, egg or milt production. A fish puts a huge amount of energy into producing its reproductive organs, massive increases of food intake that goes directly into gamete production. The flesh ultimately suffers and becomes a little looser. This can be seen by the spread of the fillet, or the flaking, when the respective meats are put side by side. Of course the easiest way to tell if your eating farmed or wild is the size. Most eateries will use 4-600g fish as they are a fair bit cheaper than 6-800g. As for taste the farmed is a great product, the only farmed fish (apart from salmon) that we sell, and lends itself well to all dishes that a sea bass would normally be used in. Again the wild bream has a slightly cleaner less oily taste. These differences are not to the extremes of wild bass Vs farmed bass. I am confident no-one has eaten wild Gilthead in a restaurant; many would have eaten farmed sold as wild, a common trick especially in the lower end Italian establishments. If you see a wild gilthead or red bream (dull pink with a big eye) snap them up.

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