Analysing Otter Spraint getting started

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Howard O’Connor’
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Analysing Otter Spraint getting started These instructions are intended as a quick route into the fascinating world of otter spraint analysis.

Be meticulous about protecting any cuts and washing hands after collecting or handling spraint. Latex gloves are advised. We assume you know what to look for but if in doubt do not collect it.

We put self-adhesive labels before going into the field and always write the date and location in pencil when we collect the spraint.

They need to be left for 24 hours but do not come to any harm if left longer. They are sometimes easier to clean if left longer.

2 Analysing Otter Spraint getting started These instructions are intended as a quick route into the fascinating world of otter spraint analysis. There is a host more information available on our website. ( Collecting and cleaning spraint All sorts of animals use otter sprainting places including rats. Be meticulous about protecting any cuts and washing hands after collecting or handling spraint. Latex gloves are advised. We assume you know what to look for but if in doubt do not collect it. If it smells horrible it isn t otter. To begin with concentrate on those with visible fish bones. We collect our spraint in small deli pots. We put self-adhesive labels before going into the field and always write the date and location in pencil when we collect the spraint. The spraint is then soaked in the pot with a teaspoon of biological washing powder and just enough water to cover the spraint. They need to be left for 24 hours but do not come to any harm if left longer. They are sometimes easier to clean if left longer. They are washed in a kitchen sieve, (definitely a different one from the one you use in the kitchen). The cleaner they are the easier they are to identify so don t skimp on the cleaning. We air dry on newspaper. If you are doing lots at the same time beware of confusing which spraint goes with which pot. When fully dry they go back into the pots until ready for analysis. Analysing Spraint For analysis, most of us use digital microscopes attached to a laptop. A circle of black card in the bottom of the petri dish makes for better viewing. The microscopes take pictures which helps us to share difficult-to-identify bones. Binocular microscopes have better 3D viewing but are more expensive and usually do not have a camera function. Do not put too much material in the petri dish at one time and remember you are not trying to identify every single bone. Concentrate on vertebrae and scales since each spraint will have loads from each fish. Some vertebrae come from near the tail and are difficult and some are chewed ignore them. Feathers and fur we record as bird and mammal respectively. Going further with your ID is for another day. The following sheets should give you a good start. All our spraints are checked by two different people. Technical terms Centrum the central part of the vertebra. Fish vertebra (back bone) Spines (1) the long bits of bone sticking off the centrum, (2) (another meaning) the spiky things on a zyg stickleback s back and sides. Zyg (full name zygapophysis, plural zygapophases) can be at all 4 corners Fish swimming this way of the centrum. Their size, shape and position are important diagnostic features. centrum Note - All the vertebra pictures below are as if the fish is ridge swimming from right to left. top spine bottom spine Page 1

Freshwater fish species basic info for a start Stickleback

which is which, we record them on our database as

You will find details later for how to tell the difference

Most of the vertebrae have a large hole.

species. They include rudd, roach and bream.

distinctive as they often break up into triangular sections.

Perch - The scales are very distinctive.

bottom spines coming from different ends of centrum Spines

3 Freshwater fish species basic info for a start Stickleback - One of our commonest fish species. They do not have scales. We get 3- and 10- spined and, as we cannot always be sure which is which, we record them on our database as 'stickleback. You will find details later for how to tell the difference - at this stage do not bother. Most of the vertebrae have a large hole. Cyprinid - The carp family are difficult to identify to species. They include rudd, roach and bream. We group them together on the The circular scales are distinctive as they often break up into triangular sections. The vertebrae have a prominent ridge along the sides of the centrum. Both the spines come from the front and the front top zyg points upwards. They are the only family which have a set of extra teeth in their throat known as pharyngeal teeth. These are very distinctive. Perch - The scales are very distinctive. The vertebrae are difficult - especially if you also get bullhead. Eel - No scales but very distinctive vertebrae with top and bottom spines coming from different ends of centrum Spines Spines base plate like a face mask Scales Pike - with no spines. Very distinctive oblong-ish scales. Stone Loach - knobbly appearance and bootshaped zyg. Pharyngeal teeth Scale Bullhead - No scales. Top spine tapers from a broad base. Prominent front top zyg. Distinctive hookshaped operculum bone (hard bony flap protecting the gills). Operculum Salmonid (Salmon, trout family) Honeycombed centrum - contrasts with v. smooth front and rear margin. Salmonid Page 2

species apart so we lump them together in

4 Non-fish prey items - fresh water and estuarine Amphibian Crustaceans Frog - e a Shrimp - pieces are distinctive shape. squidgy when grasped Bones look more solid with tweezers. than fish bones. (Not sure we can tell Teeth toads and frogs apart) Bird - Feathers. We haven t found an easy way to tell bird species apart so we lump them together in the Crayfish Not found near coast. Usually it s signal crayfish. Shell fragments obvious bright red/orange. Mammal Fur. Otters swallow some of their own fur through grooming. Identifying fur is difficult so we lump mammals together in the Fur Crab - Only found near coast/estuary. Eyes distinctive. Foot Eye Insects Fly larva - Beware. These are laid on the spraint after they ve been deposited. Teeth (vole) Beetle - Wing cases black/ brown, shiny, and v hard Newt and grass snake will be dealt with in another document Page 3

Brackish/estuarine fish Goby e very small.

Goby scales have more fingers and they are more deeply cut.

The most distinctive feature - little projections on sides - like tiny stabilisers.

Scale Warning - do not confuse this scale with perch Blenny/ Eelpout (same thing) Bones

Other estuarine species crop up and will be dealt with in another document.

5 Brackish/estuarine fish Goby e very small. Scales - (not commonly found) can be confused with perch. Goby scales have more fingers and they are more deeply cut. Flatfish Centrum looks rectangular, vertically, and has long spines, often broken. The most distinctive feature - little projections on sides - like tiny stabilisers. (Turn it on end to see) side view top view Rockling V distinctive, strongly-waisted centrum. Fin-like rear zyg. Other members of the cod family are possible, but in our estuaries rockling are the most common. Scale Warning - do not confuse this scale with perch Blenny/ Eelpout (same thing) Bones sometimes greenish. The vertebrae have a prominent ridge along the sides of the centrum. Other estuarine species crop up and will be dealt with in another document. You are welcome to use this guide in any way you want. Please let us know if you improve on it. More advanced help with identifying species can be found on our website: Contact us through the website. Many thanks to photographers Arthur Rivett, Gill Hammond, Richard Woolnough, Dennis Brown, Rodney West, Nicky Rowbottom. Page 4

Insights into otter diet from spraint analysis. - Rob Britton, student research teams at Bournemouth University & Pete Reading

Insights into otter diet from spraint analysis - Rob Britton, student research teams at Bournemouth University & Pete Reading Overview 1. Introduction into spraint analysis 2. Analysis of spraints collected