Scottish shellfish farm production survey 2018

Production

The survey indicates that the shellfish species cultivated in Scottish waters in 2018 were:

1. A proposed name change to Magallana gigas remains controversial (Bayne et al. 2007, Journal of Shellfish Research. 36, 545-547)

Production was dominated by mussel and Pacific oyster, although small quantities of scallop, queen scallop (queen) and native oyster were also produced. The 2018 production data for each species by region are given in Table 1. Additionally in 2018 there was cultivation of whiteleg shrimp (Litopenaeus vannamei) and common periwinkle (Littorina littorea) however, due to the small number of these species being produced it is not possible to summarise these without revealing commercially sensitive information. 

Table 1: Scottish Shellfish Production by Region, 2018.

NB: This report lists regions with active shellfish farms operated by authorised aquaculture production businesses.

Conversion to weight used the following assumptions (based on industry figures): individual oysters averaged 80g; individual scallops averaged 120g; individual queens averaged 40g.

Table = Sales directly for human consumption;

On-growing = Sales to other businesses for on-growing.

Table production by species is illustrated in Figure 1, while trends in production for the table market and on-growing in Scotland are presented in Table 2. 

Table 2: Trends in production data for the table and on-growing 2009-2018.

Mussel production, for the table, decreased by 16% in 2018 (see figure 1 below) to 6,874 tonnes. The greatest contribution in regional mussel production was from Shetland, accounting for 5,160 tonnes or 75% of Scotland’s total. Pacific oyster production decreased by 20% from 2017. The Strathclyde region produced 49% of Scotland’s farmed Pacific oysters. Queen scallop production decreased by 93% since 2017 while the production of farmed scallops decreased by 34% with both these sectors continuing to target small niche markets. Production of native oysters decreased by 29% from 2017. Native oyster production accounts for a small percentage of total oyster production, however, demand for this species continues to be high. Historical data for all shellfish species show that production levels vary year on year. This can be due to a number of different factors such as poor spat fall, algal toxins, poor growth, adverse weather and fluctuations in market prices. 

Figure 1: Table production by species 2009-2018.

Prices of farmed shellfish fluctuated throughout the year. Their value at first sale was estimated from the following figures obtained from the shellfish farming industry. These vary with demand, level of production and geographical area of origin. The average price of Pacific oyster was £0.37 per shell; native oyster, £0.60 per shell; scallop, £1.83 per shell; queen scallop, £0.13 per shell and mussel £1,138 per tonne. The value of the table trade is estimated from the production figures shown in Table 1 above.

Mussel: £7.8 million

Native oyster: £0.09 million

Queen: £0.002 million

Pacific oyster: £1.5 million

Scallop: £0.06 million

In 2018, the total value at first sale for all species was calculated at approximately £9.5 million, a decrease of 23% from the £12.4 million estimated in 2017.