Northern fulmar (Fulmarus glacialis)

Figure 1. Trends in abundance index of northern fulmar 1986–2019 for the UK (red), Scotland (blue), England (black) and Wales (orange). Further details, including 95% confidence limits, can be found in the individual country sections below. Based on SMP data; view the methods of analysis.

There has been considerable regional variation in northern fulmar abundance trends since monitoring began in 1986 (Figure 1). Populations in Scotland have declined rapidly over this period, contrasting with Wales where the trend has fluctuated more widely and the decline has been less severe. In England, northern fulmars have only twice been recorded above the baseline (in 1995 and 1997) and have since decreased. More detailed information can be found in the individual country sections below.

An insufficient number of northern fulmar colonies are monitored in Northern Ireland, Republic of Ireland, Isle of Man and Channel Islands, to allow the production of valid annual abundance trends.

Productivity

Figure 2. Trends in breeding productivity (no. of chicks fledged per pair) of northern
fulmar 1986–2019 for the UK (red), Scotland (blue), England (black), Wales (orange) and Isle of Man (purple; 1986–2014). Further details can be found in the sections below. Based on SMP data; view the methods of analysis.

There has been considerable regional variation in northern fulmar productivity trends since monitoring began in 1986 (Figure 2). A large proportion of the nests monitored for productivity are based in Scotland and as such, the UK and Scottish trends are closely matched. Productivity values in England and Wales between 1986 and 2006 were often higher than Scotland, although, since then, have been more similar. Productivity on the Isle of Man has been low throughout the monitoring period. An insufficient number of northern fulmar colonies are monitored in Northern Ireland, Republic of Ireland and the Channel Islands to allow the production of valid productivity trends.

Figure 3. Trend in UK abundance index (solid line) of northern fulmar 1986–2019 with 95% confidence limits (dotted lines). Based on SMP data; view the methods of analysis.

Census results indicate a large increase between 1969-70 (291,000 pairs) and 1985-88 (517,000 pairs), with numbers then stable up to 1998–2002. Data collected by the SMP suggest the abundance of fulmars breeding in the UK reached a peak in 1996 (Figure 3) but has been declining since then, although there was some fluctuation around the turn of the century and more recently in 2016. The index for 2019 (37% below the baseline) is the lowest value recorded since the index began in 1986.

The causes of long-term increase in the UK northern fulmar population is the subject of debate; some suggest an increase in food supplied by man¹ – formerly by waste from whaling fleets and later offal from trawling – while others suggest oceanographic changes², or even a genetic change in the population³. Indeed, recent declines in the abundance index may in part be due to declines in offal from trawlers, representing a 're-adjustment' to more natural levels following a period of artificially elevated population size.

From 2015 to 2019, the obligation that all catches of regulated commercial species had to be landed and counted against quota was phased in across the majority of EU fisheries. Following departure from the EU, the UK gained competency to manage fishing activities in its waters. This is regulated by the UK Fisheries Act 2020 which includes a 'Discard prevention charging scheme', although this has not yet been implemented. Reductions in discards are likely to have impacted seabird species that feed on them. Species native to the north-east Atlantic that exploit fishery discards are black-legged kittiwake, herring gull, lesser black-backed gull, great black-backed gull, great skua, northern fulmar and northern gannet⁴.

Northern fulmars are also caught accidentally by long-line and coastal gillnet fisheries in NE Atlantic waters. At least ten seabird species were recorded as bycatch by observers on UK-flagged fishing vessels in UK and immediately surrounding waters⁵. Northern fulmar was the species estimated to experience most bycatch, with an estimated capture of 2,200–9,100 birds annually (mostly in northern offshore longlines). A Population Viability Analysis showed that with the removal of all bycatch mortality, the UK fulmar population could theoretically increase between 2.1– 17.1% over a 25-year period⁶. The uncertainties in these figures are considerable due to small sample sizes, and increased monitoring of bycatch will be required to refine them.

Reductions in sandeel abundance and changes to plankton communities^7,8,9, probably caused by increases in sea surface temperature, may also be contributing to recent fulmar declines.

Table 1 below shows how numbers have changed at some of the most important UK colonies, within the Special Protection Area (SPA) network, since the Seabird 2000 census. Numbers have fallen in all areas, although the greatest declines appear to be at colonies in the north and west of the UK.

Figure 4. Trend in UK breeding productivity (no. of chicks fledged per pair) of northern fulmar 1986–2019. Based on SMP data; view the methods of analysis.

Declines in northern fulmar productivity between 1996 and 2004 may have contributed to the population decline shown in Figure 3. Since 2006 the index has fluctuated but has started to climb again, albeit very slowly. In 2019, the number of chicks fledged per pair was 0.39.

Figure 5. Trend in abundance index (solid line) of northern fulmar in Scotland, 1986–2019 with 95% confidence limits (dotted lines; drawing of upper limit restricted to preserve detail in the abundance index). Based on SMP data; view the methods of analysis.

Scotland holds the majority of the UK northern fulmar population (approximately 97% during the Seabird 2000 census) so it is unsurprising that the trend shown above closely matches the UK trend, with the key feature being the protracted shallow decline evident since the mid-1990s. Longer-term census results indicate a large increase between 1969-70 and 1985-88, although numbers had declined by the time of the Seabird 2000 census (1998–2002). The probable causes of their population increase then decrease, and current pressures affecting the Scottish population, are the same as those referred to in the UK section. The index in 2019 was 42% below the baseline, its lowest point since monitoring began.

Productivity

Figure 6. Trend in breeding productivity (no. of chicks fledged per pair) of northern fulmar in Scotland, 1986–2019. Based on SMP data; view the methods of analysis.

The trend in productivity for Scotland closely matches that of the UK because much of the data have been collected at Scottish colonies. Comments under the UK section are also pertinent to Scotland. Declines in productivity since the mid-1990s may have contributed to the observed fall in abundance since that time, although it should be noted that immature birds take approximately nine years to recruit into the breeding population. Since 2009 the index has fluctuated, although has started to climb again, albeit very slowly. Heavy rain at several colonies is likely to have contributed to the decline in productivity observed in Scotland in 2015. Between 2016 and 2019, the number of chicks fledged per pair decreased from 0.47 to 0.39.

Figure 7. Trend in abundance index (solid line) of northern fulmar in England, 1986–2019 with 95% confidence limits (dotted lines). Based on SMP data; view the methods of analysis.

In England, northern fulmar numbers almost doubled between the first two national censuses but appeared to stabilise afterward. Their distribution in England is roughly split between the north-east and south-west (see Distribution section). However, most regular monitoring occurs in the north-east where several colonies have been counted annually up to 2019. Between the years 2000 and 2010, the index fluctuated with no discernible trend but then declined sharply to 45% below the baseline in 2014. Since then, the index has risen and was 25% below the baseline in 2019.

Productivity

Figure 8. Trend in breeding productivity (no. of chicks fledged per pair) of northern fulmar in England, 1986–2019. Based on SMP data; view the methods of analysis.

The productivity of northern fulmars in England shows no clear trend over the monitoring period. Productivity is generally moderate to high and seldom falls below 0.40 chicks fledged per pair. In 2019, productivity was 0.45 chicks fledged per pair, matching the 1986–2019 average.

Figure 9. Trend in abundance index (solid line) of northern fulmar in Wales, 1986–2019 with 95% confidence limits (dotted lines; drawing of upper limit restricted to preserve detail in the abundance index). Based on SMP data; view the methods of analysis.

The abundance index of northern fulmars in Wales shows an increasing trend at least up to the mid-1990s (Figure 9). The steady decline in abundance evident for the UK and Scotland starting around the mid- to late-1990s is absent, with the index being relatively stable until 2005. However, a noticeable decline then occurred until 2009, after which abundance has stabilised. The long-term change shows that numbers increased markedly after Operation Seafarer, with the population during 1998–2002 almost four times that recorded in 1969-70.

Productivity

Figure 10. Trend in breeding productivity (no. of chicks fledged per pair) of northern fulmar in Wales, 1986–2019. Based on SMP data; view the methods of analysis.

Although few data are available until 1992, productivity in Wales has on average been higher than in Scotland and England. However, there has been an overall decline across the monitoring period, with productivity reaching its lowest value recorded (0.24 chicks fledged per pair) in 2019. The reasons for this decline are unknown.

Figure 11. Abundance of northern fulmar on the Calf of Man, 1986–2019.

In common with other regions, the northern fulmar population on the Isle of Man increased considerably after Operation Seafarer. An increase of 320% occurred between 1969-70 and 1985-88 with another less dramatic increase of 28% between 1985-88 and 1998–2002. After Seabird 2000, data are available only from a few small colonies. However, the trend derived from the colonies sampled between census periods does not match the change in the Isle of Man population that is known to have occurred (e.g. from census data).

The largest colony counted regularly is the Calf of Man, where numbers have fluctuated in the late 1990s and between 2010 and 2012. Since then, there appears to have been a decline with numbers in 2014 and 2015 (both 50 AOS) at their lowest since 1986¹¹. In 2019, a very slight increase to 54 AOS occurred.

Productivity

Figure 12. Trend in breeding productivity (no. of chicks fledged per pair) of northern fulmar on the Isle of Man, 1986–2014. Based on SMP data; view the methods of analysis.

Northern fulmar productivity on the Isle of Man has fluctuated greatly over the recording period. However, within this variation there does appear to be a declining trend in productivity since the mid-1990s at least. Productivity was very low in 1995, 2003, 2006, 2008 and from 2012 to 2014. In 1995, an unknown proportion of chicks died from heat stress during a hot and dry summer, and in 2012 low productivity was probably due to high rainfall during June and July. The reasons for low productivity in other years are unknown. No productivity data on northern fulmar have been submitted to the SMP since 2014.