Status Assessment 2021 - Spotted ray
|Assessment of status||Distribution||Population size||Demographics, e.g. productivity||Previous OSPAR status assessment||Status|
|Assessment of key pressures||Key pressure Excessive mortality (bycatch fisheries)||Key pressure||Habitat damage||Threat or impact|
Explanation to table:
Distribution, Population size, Condition
Trends in status (since the assessment in the background document)
↓ decreasing trend or deterioration of the criterion assessed
↑ increasing trend or improvement in the criterion assessed
←→ no change observed in the criterion assessed
? trend unknown in the criterion assessed
Previous status assessment: If in QSR 2010 then enter regions where species occurs ( ○) and has been recognised by OSPAR to be threatened and/or declining (● ). If a more recent status assessment is available, then enter ‘poor’/’good’
red – poor
green – good
Blue cells –? status unknown, insufficient information available,NA - Not Applicable
*applied to assessments of status of the feature or of a criterion, as defined by the assessment values used in the QSR 2023 or by expert judgement.
↓ key pressures and human activities reducing
↑ key pressures and human activities increasing
←→ no change in key pressures and human activities
? Change in pressure and human activities uncertain
Threat or impact[overall assessment]
red – significant threat or impact;
green –no evidence of a significant threat or impact
Blue cells –? insufficient information available
NA– not applicable
1 – direct data driven
2 – indirect data driven
3 – third party assessment, close-geographic match
4 – third party assessment, partial-geographic match
5 – expert judgement
The spotted ray was first nominated for inclusion in the OSPAR List of Threatened and/or Declining Species and Habitats in 2001 and it was last assessed in 2010. The key criteria for listing were a decline, sensitivity and rarity within Belgian waters (Region II) where spotted ray was considered to be a common occurrence in the mid-1900s. More contemporary studies in the North Sea (and other parts of Region II) and in other parts of the OSPAR area have shown increases in the relative abundance of spotted ray. Nevertheless, the species remains rare in Belgian, German, Norwegian, and Swedish waters. There is some uncertainty regarding its historical occurrence and abundance in many of these areas.
The status of this species is based on ICES advice to fisheries managers for fishing opportunities. This advice has been integrated into an assessment for conservation purposes.
Geographical Range and Distribution
The spotted ray is a small-bodied skate that is widely distributed in the Northeast Atlantic; its absolute range extends from Morocco in the south to the Shetland Isles and Scandinavia in the north, and includes the Mediterranean Sea (Ellis et al. 2007). Within the Northeast Atlantic (OSPAR Regions II, III and IV) it tends to occur in shelf seas at depths of 8m to 400m (Ellis et al. 2005, ICES 2018), although it is most common in waters less than 150m deep (ICES 2018). Juveniles tend to occur closer inshore on sandy sediments, with adults more common further offshore on sand and coarse sand-gravel substrates.
ICES provides advice on fishing opportunities for five stocks of spotted ray: (i) ICES Subarea 4 and Divisions 3.a and 7.d (OSPAR Region II); (ii) Divisions 7.a,e-h, and (iii) Subarea 6 and Divisions 7.b and 7.j (OSPAR Region III); (iv) Subarea 8 and (v) Division 9.a (OSPAR Region IV).
An increasing stock size indicator has been observed for OSPAR Region II since 2009 (Figure 2a). Stock size indicators are also increasing in recent years in OSPAR Region IV.
Recorded length-at-maturity (L50) for spotted rays measures 50.9 cm in total length (TL) for males and 62.5 cm TL for females (McCully et al. 2012). The observed length range was 10–67 cm TL and 10–76 cm TL for males and females, respectively (McCully et al. 2012). Juveniles and egg cases are often abundant in sheltered inshore nursery areas, e.g. Welsh and eastern Irish coasts (Ellis et al. 2005). Length data for spotted ray in the North Sea, Skagerrak, Kattegat and eastern English Channel, derived from scientific surveys, have shown no trend in the average length over time and are relatively stable in terms of length range. Individual rays up to the expected maximum length have been reported consistently over the time series. The length distribution of spotted ray obtained from a Portuguese survey in Division 9a is also relatively stable over the time-series (ICES 2019b).
Threats and Impacts
The main threat identified in the last assessment was “fisheries mortality (primarily bycatch in commercial fisheries)”. Habitat damage (e.g. due to mobile fishing gears, pollution, eutrophication) was also considered but not evaluated (OSPAR 2010).
A decrease in fishing effort is shown in the Northeast Atlantic from the beginning of the 21st century (e.g. Gascuel et al. 2016; Couce et al. 2020, ICES 2020e). However bycatch remains a threat to the species.
Measures that address key pressures from human activities or conserve the species/habitat
For EU waters, fishing pressure on spotted ray is currently regulated through a Group-TAC which includes all skate and ray species except Raja undulata and those listed as prohibited. The Group-TAC was introduced in 1999 in the North Sea (Division 3.a and Subarea 4) and in 2009 in the eastern English Channel (Division 7.d) and other areas. Recent studies suggest variable at-vessel mortality and discard survival, depending on several factors (e.g. gear type, soaking time, fish size) (Ellis et al. 2018, Schram and Molenaar 2018, Serra-Pereira and Figueiredo 2019). It is possible that this bycaught small-bodied species may be less susceptible to fishing pressure than the large-bodied skates (e.g. Silva et al. 2012), though further studies on discard survival are required.
Conclusion (including management considerations)
The ICES stock-size indicators show an increasing trend for spotted ray stocks within all OSPAR regions where the species is assessed, with OSPAR Region II showing a more pronounced increase as compared to other areas. The IUCN assessment for spotted ray is as a species of “Least Concern” (Nieto et al. 2015). However these indicative trends are relatively recent (i.e. gradual increase overall during the last decade or so) and there is also significant uncertainty (i.e. wide confidence limits) around some stock size estimates. Therefore the conclusion on the species’ status across relevant OSPAR regions is unknown with the exception of Region II in which the upward trend represents a stronger signal over a longer time-frame.
The species remains rare in Belgian, German, Norwegian, and Swedish waters. There is uncertainty regarding its historical occurrence and abundance in many of these areas but there is some evidence that the species was never abundant in the south-western bight of the North Sea (Rijnsdorp et al. 1996, Rogers and Ellis 2000). While there have been improvements in scientific understanding of this species’ biology, knowledge of their life-cycle and population structure remains incomplete.
The ongoing requirement for species-specific reporting of landings has improved the management of skates and rays. In the coming years, attention should be given to the species-specific differences in susceptibility to fishing pressure, and a species-specific approach to management could be considered.
In conclusion, the available information on spotted ray indicates slight improvements in the abundance of the species. However, long-term trends are unsure and identified threats to the species remain. Furthermore, the species fulfils the Texel-Faial criteria of regional importance and sensitivity.
Although there have been recent studies (e.g. Ellis et al. 2005, 2012, AFBI 2009, Serra-Pereira et al. 2014) on ecologically important habitats for this species, spawning and nursery grounds have yet to be fully delineated. The lack of a defined population structure may also hamper the development of potential spatio-temporal management measures. Therefore, additional tagging programmes (conventional and electronic) and DNA analyses of spotted rays throughout the distributional range could usefully be considered. Further research to examine gear selectivity and discard survival is also required.
The assessment is based on ICES stock assessments (survey trends).
Agri-Food & Biosciences Institute (AFBI). 2009. Position statement on sharks, skates and rays in Northern Ireland waters. Northern Ireland Environment Agency Research and Development Series No. 09/03, 199 pp.
Couce, E., Schratzberger, M., and Engelhard, G. H. 2020. Reconstructing three decades of total international trawling effort in the North Sea. Earth System Science Data, 12, 373–386. https://doi.org/10.5194/essd-12-373-2020.
Ellis, J. R., Burt, G. J., Grilli, G., McCully Phillips, S. R., Catchpole, T. L. and Maxwell, D. L. 2018. At-vessel mortality of skates (Rajidae) taken in coastal fisheries and evidence of longer-term survival. Journal of Fish Biology 92, 1702–1719.
Ellis, J. R., Cruz-Martinez, A., Rackham, B. D. and Rogers, S. I. 2005. The distribution of chondrichthyan fishes around the British Isles and implications for conservation. Journal of Northwest Atlantic Fishery Science, 35, 195‒213.
Ellis, J. R., Milligan, S. P., Readdy, L., Taylor, N., and Brown, M. J. 2012. Spawning and nursery grounds of selected fish species in UK waters. Science Series Technical Report, CEFAS Lowestoft, 147, 56 pp.
Ellis, J., Ungaro, N., Serena, F., Dulvy, N., Tinti, F., Bertozzi, M., Pasolini, P., Mancusi, C., and Noarbar-tolo di Sciara, G. 2007. Raja montagui. The IUCN Red List of Threatened Species 2007:e.T63146A12623141. https://dx.doi.org/10.2305/IUCN.UK.2007.RLTS.T63146A12623141.en.
Gascuel, D., Coll, M., Fox, C., Guénette, S., Guitton, J., Kenny, A., Leyla Knittweis, L., Nielsen, J. R., Piet, G., Raid, T., Travers-Trolet, M., and Shepard, S. 2016. Fishing impact and environmental status in European seas: a diagnosis from stock assessments and ecosystem indicators. Fish and Fisheries, 17, 31–55, doi: 10.1111/faf.12090.
ICES. 2018. Report of the Working Group on Elasmobranch Fishes (WGEF), 19–28 June 2018, Lisbon, Portugal. ICES CM 2018/ACOM:16. 1306 pp.
ICES. 2018. Spotted ray (Raja montagui) in Division 9.a (Atlantic Iberian waters). In Report of the ICES Advisory Committee, 2018. ICES Advice 2018, rjm.27.9a, https://doi.org/10.17895/ices.pub.4559
ICES. 2019a. Spotted ray (Raja montagui) in Subarea 4 and in divisions 3.a and 7.d (North Sea, Skagerrak, Kattegat, and eastern English Channel). In Report of the ICES Advisory Committee, 2019. ICES Advice 2019, rjm.27.3a47d, https://doi.org/10.17895/ices.advice.4839
ICES. 2019b. Working Group on Elasmobranch Fishes (WGEF). ICES Scientific Reports. 1:25. 964 pp. http://doi.org/10.17895/ices.pub.5594
ICES. 2020a. Spotted ray (Raja montagui) in divisions 7.a and 7.e–h (southern Celtic Seas and western English Channel). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, rjm.27.7ae-h. https://doi.org/10.17895/ices.advice.5813
ICES. 2020b. Spotted ray (Raja montagui) in Subarea 6 and divisions 7.b and 7.j (West of Scotland, west and southwest of Ireland). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, rjm.27.67bj. https://doi.org/10.17895/ices.advice.5812
ICES. 2020c. Spotted ray (Raja montagui) in Subarea 8 (Bay of Biscay). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, rjm.27.8. https://doi.org/10.17895/ices.advice.5796
ICES. 2020d. Spotted ray (Raja montagui) in Division 9.a (Atlantic Iberian waters). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, rjm.27.9a. https://doi.org/10.17895/ices.advice.5797
ICES. 2020e. Working Group on Elasmobranch Fishes (WGEF). ICES Scientific Reports. 2:77. 789 pp. http://doi.org/10.17895/ices.pub.7470
McCully, S.R., Scott, F., and Ellis, J.R. 2012. Lengths at maturity and conversion factors for skates (Rajidae) around the British Isles, with an analysis of data in the literature. ICES Journal of Marine Science, 69: 1812–1822.
Nieto, A. et al. 2015. European Red List of marine fishes. Luxembourg: Publications Office of the European Union, iv + 81 pp.
OSPAR. 2010. Background Document for Spotted ray Raja montagui. OSPAR Commission 2010 16 pp.
OSPAR. 2010. Background Document for Spotted ray Raja montagui. OSPAR Commission, Biodiversity Series No. 478. 17 pp. ISBN 978-1-907390-19-7.
Rijnsdorp, A.D., van Leeuwen, P.I., Daan, N., and Heessen, H.J. 1996. Changes in abundance of demersal fish species in the North Sea between 1906–1909 and 1990–1995. ICES Journal of Marine Science, 53: 1054–1062.
Rogers, S.I., and Ellis, J.R. 2000. Changes in the demersal fish assemblages of British coastal waters during the 20th century. ICES Journal of Marine Science, 57: 866–881.
Schram, E., and Molenaar, P. 2018. Discards survival probabilities of flatfish and rays in North Sea pulse-trawl fisheries. Wageningen, Wageningen Marine Research (University & Research Centre). Wageningen, Wageningen Marine Research report C037/18. : 39 pp.
Serra-Pereira, B., Erzini, K., Maia, C., and Figueiredo, I. 2014. Identification of potential Essential Fish Habitats for skates based on fisher’s knowledge. Environmental Management, 53: 985–998.
Serra-Pereira, B., and Figueiredo, I. 2019. Scientific evidences on discard survival of skates and rays (Rajidae) in Portuguese mainland waters (ICES division 27.9.a). Working Document to the Working Group on Elasmobranch Fishes (WGEF) meeting, 18-27th June 2019. 23 pp.
Silva, J. F., Ellis, J. R., and Catchpole, T. L. 2012. Species composition of skates (Rajidae) in commercial fisheries around the British Isles, and their discarding patterns. Journal of Fish Biology, 80: 1678–1703.