The Work

Specialist Report 2004 - Fish Bone

Posted by steven on 11/04/2005 at 02:19 PM

HIGH PASTURE CAVE, SKYE: ANALYSIS OF THE FISH REMAINS

Ruby Ceron-Carrasco - University of Edinburgh

Methodology

The fish remains from High Pasture Cave were recovered from Trench 1. Eight contexts contained fish remains that were retrieved by sieving though 1.5 mm mesh size.

Where possible, all the remains were identified to species level or to family group. Identification of the fish remains was done by reference to a modern fish bone collection and to standard guides (Watt et al 1997). Nomenclature follows Wheeler & Jones (1989, 122-123).

All elements were examined for signs of butchery and burning. The colour of burnt bone was recorded to allow investigation into the nature of burning, i.e. cooking, rubbish disposal, etc.

The sizes of the cod-family species, the Gadidae, have been given as an approximate size range. This was done by matching the archaeological material to modern fish skeletons of known size based on ‘total body length’. Therefore, the elements were categorized as ‘small’ (15-30 cm), ‘medium’ (30-60 cm) and ‘large (60-120 cm).

The recording of preservation state of the fish bone was based on two characters: texture on a scale of 1 to 5 (fresh to extremely crumbly) and erosion also on a scale of 1 to 5 (none to extreme). The sum of both was used as an indication of bone condition; fresh bone would score 2 while extremely poorly preserved bone would score 10 (after Nicholson 1991).


Fish bones from High Pasture Cave

Results

The results of the identification of the fish bone elements are given in the catalogue.  The summary of species present and NISP (Number of Identified Species by fragment count) is given in Table l. The material was found to contain well preserved as well as quite eroded and very fragile fish bone. Their condition score was generally in the range of 4-8 indicating well-preserved to extremely poorly preserved bone. Skeletal elements were most frequently 50-70 % complete. Unidentifiable fragments consisted of mainly cranial fragments and tiny fragments of ribs and fin rays; these were not considered in the results tables as they would have given a distorted image of representation due to their large amount, these are mainly the results of post-depositional and post-excavation damage.

A total of nine taxa were identified consisting of six identified to species and three to family level. The assemblage has a varied representation of several family groups of mainly marine fishes. The main group represented in the assemblage was herring.

Taxonomical analysis

Herring (Clupea harengus) was the main species represented in the assemblage. Other marine species recovered included saithe (Pollachius virens), cod (Gadus morhua) other unidentified Gadidae, mackerel (Scomber scombrus), remains of Pleuronectidae (left-eyed flatfishes) as well as the tiny butterfish (Pholis gunnelus). Remains of vertebrae of eel (Anguila anguila) were also present in the assemblage.

Description of the species found in the High Pasture Cave fish bone assemblage
(Based on Wheeler 1969 and 1978).

Herring (Clupea harengus), Clupeidae family, is one of the most important fish species in Scotland’s fishing history, and Scotland has been particularly fortunate in relation to its migratory habits which has secured its presence in the west coast particularly in winter time (Gray 1978). Herring grows up to 45 cm in total length and most of the elements recovered from this species at High Pasture Cave were from mature specimens of between 35-45 cm total length.

Saithe (Pollachius virens) is a common fish occurring in northern inshore waters, it spawns from January to April.  Young, immature, fish are found close inshore among weed-covered rocks and open bays. This ‘immature phase’ lasts for at least two years; mature fish are found slightly offshore. The growth pattern of Saithe is of an approximate average of 15 cm increase in length annually for the first three years followed by a pattern of 10 cm annual growth for the next three years; the species can reach a total length of 100 cm. Although elements from large (60-120 cm total length) specimens were recovered at High Pasture Cave, saithe was mainly represented by ‘very small’ (< 15cm total length) and ‘small’ (15-30 cm total length) specimens in the assemblage.

Cod (Gadus morhua) is another of the most important food fishes of the Scottish fishing industry, and has been exploited ever since man begun to fish the seas of Europe. Its value as prime food is enormous, its firm flesh allowing for preservation as ‘stock fish’, dried or salted, for winter consumption or trade. Its growth rate varies with different populations, in the North Sea it can grow to an average of 18 cm in their first year, 36 cm in their second year, 55 cm in their third year and 68 cm in their fourth year. A mature cod can reach 150 cm in length and weigh up to 40 kg. The cod is widely distributed in a variety of habitats from the shoreline to well down the continental shelf, in depths of 600 m. The younger smaller fish usually remain close inshore. Cod remains at High Pasture Cave were from specimens of between 30 cm to 120 cm total length.

Mackerel (Scomber scombrus), Scombridae family, is a common North Atlantic fish living near the surface of the sea in large shoals. It is found seasonally close inshore. It attains a maximum length of 66 cm. Elements of Mackerel recovered at High Pasture Cave were from specimens of up to 60 cm total length.

The butterfish (Pholis gunnellus), family Pholidae, is a common fish found mainly on rocky shores, it may attain up to 25 cm. Specimens present in the assemblage were from individuals of less than 15 cm total length and were probably used as fishing bait and are the remains of other species’ stomach contents.

Eel (Anguilla anguilla) are found throughout Europe and in all parts of the British Isles. Most enter freshwater habitats while some may remain near the coast, in particular on rocky shores. Their migrations from the Sargasso Sea to Europe are well known. Male specimens may attain a total length of 50 cm whilst the females may attain up to 100cm. Eel was represented by mainly vertebra from specimens of less than 45 cm total length in the High Pasture Cave assemblage.

Conclusion of the analysis

None of the fish remains recovered at High Pasture Cave showed any signs of digestion or of gnawing which may have been incurred by other mammal such as the coastal otter (Lutra lutra), one species only is presumably derived from the stomach context of other species present in the assemblage, the small butterfish (Pholis gunnelus) which may have been used as bait for catching the larger specimens such as adult cod. The fish remains present at the cave therefore are considered to be the remains derived from species that were caught by humans to be consumed on site.

Fishing from rocks for young saithe would have produced young cod, and other species such as mackerel. The use of boats and hand-lines would have been required for the catch of mature cod.

Eels are usually present in assemblages from different periods and have probably been systematically exploited throughout Scotland. These can be easily caught using wicker traps in freshwater streams or on coastal waters.

Herring was the main species represented in the assemblage and their presence indicates that boats and nets may have been used for catching these, although they can occasionally be caught on line. Furthermore, fishing for herring since at least the 16th century was also done close inshore using trap-nets (also known as stake-nets or herring baulks) or weirs; close inshore one boat with net would have been sufficient to ensure a good catch.

Herring remains have been recovered only in quite small quantities in fish bone assemblages dating to the Norse period in Northern Scotland whilst, in Western Scotland only one other site dated to the Later Iron Age produced a minimal amount of herring vertebra, at Dun Vulan in South Uist (Ceron-Carrasco 1999). Therefore remains of herring are insignificant during this period when compared to the large amounts of cod-family fishes (Gadidae) remains found throughout prehistoric sites in Scotland. However, unlike the Northern Isles and Caithness, herring in the Western Isles becomes increasingly important and occurring in large quantities in assemblages from the Norse period (Ceron-Carrasco 2002). The presence of herring at High Pasture Cave is therefore quite significant in this area if indeed the assemblage dates to the Iron Age.

References

Cerón-Carrasco R. 1999 ‘The fish remains from Dun Vulan, South Uist’, in Parker-Pearson, M. & Sharples, N. Between Land and Sea. Excavations at Dun Vulan, South Uist. Sheffield: Sheffield Academic Press.

Cerón-Carrasco, R. 2002 ‘Of fish and men’ (De iasg agus dhaoine): Aspects of the utilization of marine resources as recovered from selected Hebridean archaeological sites’. D.Phil. Thesis. University of Edinburgh

Nicholson, R.A. 1991 An investigation into variability within archaeologically recovered assemblages of faunal remains: The influence of pre-depositional taphonomic processes. D. Phil. Thesis. University of York.

Watt, J., Pierce, G. J. & Boyle, P. R. 1997 ‘Guide to the Identification of North Sea Fish using Premaxilla and vertebra’. ICES. CooperativeResearch Report No. 220. Denmark.

Wheeler, A. 1969 The fishes of the British Isles and North-West Europe. Macmillan. London.

Wheeler, A. 1978 Key to the fishes of Northern Europe. London: Frederick Warne.

Wheeler, A. & Jones, A. K. J. 1989 Fishes. Cambridge Manuals in Archaeology. Cambridge University Press.


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