Monday, 2 November 2009

Skating on Thin Ice - The Plight of our skates and rays

Skates and rays are ancient and stunningly beautiful creatures thought to have been with us for 150 million years. There are approximately 600 species throughout the world including 21 around the coast of the UK; varieties also include electrical and stinging species. They derive from the class Chondrichthyes and fall into the sub-class elasmabranchii that also includes the sharks. The close relationship of the skates and sharks mean they both differ from the bony fish as their endoskeleton is made entirely of cartilage. The differences do not stop their as unlike many bony fish the skates and rays do not have scales; they are either armed with mucus covered skin, common to the spotted ray, or bony armoured projections called tubercles. They are very sociable animals and can commonly be found in large groups sometimes in piles on top of each other. They glide effortlessly through the water using their huge pectoral fins, commonly known as wings that move by waves of dorsoventral muscle contractions, whilst using their long whip like tail as a rudder. Their beautiful markings, normally characteristic of their specific environment, are used as camouflage as they lie lifeless disguised on the sea bed; camouflage on the sea bed is a great form of predator defence.

The beautiful markings of a Cuckoo Ray

They are slow moving bottom dwellers and spend a large amount of time laying on the sea bed so have their mouth on the underside of the body which traps prey against the substrate. They are ambush predators commonly laying in wait too pounce on their unsuspecting prey grasping them with compact rows of strong pointed teeth.

The skates and rays have evolved additional help in breathing; their five to seven pairs of gills on the underside of the body would continuously become clogged with silt if no help was at hand. On the top of the body, alongside each eye, there is an opening called a spiracle. Water is taken into these vents and then past over the gills allowing the oxygen to be removed. Similar to sharks the skates have great senses and having electro receptors that are able to detect electricity produced by prey.

Male skates have specialised fins known as claspers that can be seen either side of the tail on the underside. Mating is quite violent with the males commonly biting into the females. The fish generally have a late age at maturity, between 5 and 10 years, and the females produce only a small number of spiny egg cases, less than 100 per year, and these are commonly known as mermaids’ purses. Depending on the species and certain environmental factors their eggs can take 6 to 12 months to hatch; some species of sting rays do bear live young.

The catch levels into UK ports of the main species approaches 2-3000 tonnes per year. Considering that nearly all caught skates are part of the bottom trawl by-catch these levels are quite high. Being a by-catch species has particularly bad consequences as it is very difficult to ascertain accurate catch levels. Managing fisheries with figures ascertained from by-catch data make effective fishery management hugely difficult. Additionally over the past decades all species have been recorded in the generic skate and ray family resulting in little or no accurate historical commercial catch records; without this data it is impossible to assess stock level fluctuations over time. Since 2009, however, a species specific recording system has become compulsory. The retention of the common skate species is now illegal in the majority of the Europeon waters and must be returned alive if caught. This is also true of the undulate ray species.

Of the many species across the world we need only to centre around a small percentage of local varieties. The stage is taken by the critically endangered common skate (Dipturus batis), the species of categorised ray thought to be at low or critical levels n certain areas including the Thornback (Raja clavata), Undulate (Raja undulata), Blonde (Raja brachyura) and Painted or otherwise known as small-eyed (Raja microcellata) and the species deemed at safe levels which include the Cuckoo (Leucoraja naevus), spotted (Raja montagui), and the Starry (Raja radiata).

So why has the skate, and to a lesser extent certain species of ray, found themselves on the endangered list. They are not particularly fashionable like the blufin or other species of tuna, delicate like halibut or even as easy to cook as cod. Unfortunately the skates and rays have one huge disadvantage when compared to these species. They take time to mature and reproduce very slowly in incredibly small numbers. Unlike a mackerel that will release many thousands of eggs per fish the rays will lay a small number per female. The majority of shoaling species work on the theory that a mass production of eggs will yield a small percentage of survivors. If, for example, the female population were halved the tiny survival rate would also be halved; the problem that created the cod stocks to collapse of the west coast of Canada. So if the species only lays a small number of eggs to start with then it is critical a large percentage survive. Ultimately a stock can reach no return when the spawning stock is not large enough to successfully recruit and the species becomes extinct – when only two males are left the Adam and eve theory reverts to Adam and Steve – no reproduction.

The EC have recently proposed a 15% cut in Total Allowable Catches across the board within EC waters. The landing of Common Skate, Norwegian Skate, White Skate and Underlate Ray remains illegal in many European waters.

For many years the skate in England and the Ray in France have traditionally appeared on restaurant menus or in front of the family at dinner time; served with black butter and capers or more commonly in England battered with chips. In more resent times skate has become a popular dish offered by some of the top London establishments; maybe it offers something quintessentially English?

Personally, I have not seen a piece of Common skate for a number of years and although our shop is situated in the heart of London’s largest and wealthiest French and English communities the demand for this, and ray species, is minimal. I put this down to my choice of rarely offering this product; I am one of the people fascinated by them in their own environment. On a Friday the shop will offer a small amount of carefully selected ray species that I am happy with selling. I understand it can be very hard for certain businesses when the most talked about ‘must avoid’ species are also the most popular. In a way I feel sorry for restaurants such as Nobo, Scotts and Sheekeys as they are being publicly pressured into to removing dishes they have sold for many years, dishes that are signature of their restaurant, dishes that will leave gaping holes in their menus, holes that cannot be filled. However, nobody can condone the selling of an endangered species, aquatic or not, so these restaurants will have to come to terms with this and adapt their menus accordingly. Those that do not will eventually find themselves ostracised which will be more damaging long term to their businesses.

I certainly believe the majority of restaurants, including those so heavily criticised on recent ‘where not to buy fish’ websites which offer skate on the menu, are in fact selling species of sustainable ray (websites such as the recent which was removed for a short period and updated as inaccuracies and assumptions where leading to possible libel action). The problem that occurs is that all these species encompass the group of true skates. All of our commercial species are then split into the larger species with long snouts (true skates) and the smaller short snouted species (rays). Although technically they can all be called skate on the menu it is time, with increased pressure of knowing some are critically endangered, to label our dishes, and in the case of fishmongers, their counters, correctly. Not until 2009 has the fishing industry been forced into labelling each variety as species specific.

Common Skate

Many chefs and fishmongers will not recognise the difference between the many species. In fact many would have never sold common skate. However, many of the menu inaccuracies involving skate are accidental and without true malice, but those restaurants that have known they have been selling ray as skate will now feel uneasy with recent publicity. Conversely, many will be happy with their labelling as technically it is correct and the assumption by the recent fish2fork website that menu citing of skate are automatically the endangered species are very assuming and in most cases wholly inaccurate. I am also told there is a certain amount of misleading undertaken by some wholesalers and fishmongers and I have also seen the smallest of immature ray wings labelled as skate in the so called ‘green’ supermarket. The real problem is that over the past ten years everybody has just called all species skate. It was just easier that way. It was a name everybody recognised. “Portion of skate and chips please love” just makes more sense than “Portion of small-eyed ray and chips please”. This however needs to change. People are aware of the uneasy plight of certain species of fish. Shops and restaurants need to re-label. It is not acceptable to sell endangered species of Skate so why use the name. The rays have such beautiful names so use it as a sale pitch.

So what is my advice on buying or not buying skate and ray? Due to the lack of data it has been very difficult in finding any real help to answer this question. The website offers its usual level of worthless help by suggesting the stock levels of most species is uncertain. Fish2fork seem to categorise all species as skate thus assuming they are critically endangered without any real justification. Seafish ‘the authority on seafood’ (their branding) offer little more than a lack of data gives insufficient results. The IUCN red list offers little unless well hidden in its site. For example the Thornback Ray, categorised by Seafish (with reference to IUCN) as ‘near threatened’ is actually categorised as lower risk by the IUCN – all very confusing and might I say misleading. All I can suggest is to follow the following list and you should buy the tastiest meal that hasn’t come from a critically endangered species.

Your purchased piece of fish should be as pink as possible (see picture below) – remember ‘White will be shite’. The older the fish the whiter it will be so if no colour remains walk away.

Many will know that an old piece of skate will smell of ammonia but why?
The skates retain nitrogenous wastes such as urea in their blood stream to help water from being drawn out of them via osmosis. When combined with blood salts the concentration is raised above that of the surrounding water resulting in osmotic equality. If it smells do not eat it.

And finally with regards to ethical selection the size may be your only help. As the very large species of True Skates and the Underlate Ray are now rarely or never landed I would suggest avoiding the very small wings that would come from immature fish. It is hard as the smaller species are believed to be the most abundant, but rarely will any have reached maturity at a small size. Buy whole wings that weigh 700grms+ or pieces that have come from wings this size or above. Maybe your ideal size to guarantee your fish had reached maturity and had been given a chance to spawn would be bigger still.

To note – Unlike the cleanly skinned Blonde Ray wings in the picture below the common skate has small black squiggly lines left on the flesh after skinning (they are part of the skin that remains and could be likened to black worms?) and I believe is the only species that does. If you see it for sale you’ll know it is from a critically endangered species.


  1. Hi there,

    I like this blog. I Like the way you point out the difficulties in assertaining catch data, and I like the way you have given the specific names of the fish that are at risk and those that are not.

    One thing I did notice was that the paragraphs are quite long. break this up a bit more and it will improve its readability. Another thing I noticed was that you give tons of information about skates at the beginning but you don't mention their precarious situation. I recommend you make the point that many species of skate are on the IUCN endangered list and others are given tentative statuses.

    Over all I think it's a great blog and it really shows that you know what you are talking about. Its nice to see someone with your background talking about this subject. It flows nicely too.

    I would like to attach it to a few other sites to capture an audience that needs it so if you could re-look at it and maybe have a bit of a muck around with the spacing and the message then I would love to use your link if that's ok.


    Marine Ecologist

  2. Thanks for your positive comments Jon. I am actually in the process of re-writing this piece for a customer with the addition of all the species and red list and fish list ratings. when I have finished I will add segments to the blog so it reads much clearer.