The Whiteblotched Skate (Bathyraja maculata) is a medium-sized deepwater skate (to at least 147 cm total length) known from a widespread distribution in the North Pacific Ocean, from northern Japan through to the Sea of Okhotsk and the Bering Sea to the Aleutian Islands and Gulf of Alaska, United States. It has been recorded on continental and insular shelves and slopes at depths of 73–1,200 m. Across the North Pacific Ocean, skates are bycatch of industrial trawl, longline, and trap groundfish fisheries, and in some areas, skates comprise up to 10% of the total recorded biomass. The Whiteblotched Skate is a bycatch of fisheries targeting groundfish, including Pacific Cod (Gadus macrocephalus), Alaska Pollock (Gadus chalcogramma), and Greenland Halibut (Reinhardtius hippoglossoides). The species is among the most abundant skates in the Aleutian Islands where demersal trawl surveys reveal a stable population. There is increasing international demand for skate products in countries including China, Japan, and Korea and this increased demand has increased skate retention and interest in developing skate targeted fisheries. There are catch limits set for skates (as a group) in Russian and United States waters. Areas of high skate egg density in the United States Bering Sea and Aleutian Islands are designated Habitats of Particular Concern which allows management intervention where fishing activity is deemed harmful to the habitat. The population is estimated to be stable where it most commonly occurs and it has deep water refuge across its range from current fishing activities. The Whiteblotched Skate is therefore assessed as Least Concern.

The Whiteblotched Skate is found in the North Pacific Ocean, from northern Japan through to the Sea of Okhotsk and the Bering Sea to the Aleutian Islands and Gulf of Alaska, United States (Last et al. 2016).

Across the North Pacific (western Bering Sea, Sea of Okhotsk, Northwest Pacific Ocean), trends in catch-per-unit-effort (CPUE) have generally increased by more than two-fold between 1977 and 2021 (Orlov and Volvenko 2022). This increase in CPUE is considered to be reflective of market value (Orlov and Volvenko 2022). Skate abundance data are available for the Aleutian Islands (AI), eastern Bering Sea (EBS) slope, and EBS shelf and are based on demersal trawl surveys conducted by the U.S. National Marine Fisheries Service (Ormseth 2020, Tribuzio et al. 2023). The Whiteblotched Skate is reported primarily from AI and along with the Aleutian Skate (Bathyraja aleutica), is the most abundant species in this region. Biomass estimates in the AI have fluctuated slightly but were overall stable from 2000–2023. Biomass estimates on the EBS slope show some increasing trend between 2002–2023; EBS shelf data are insufficient to determine trends. Total modelled biomass estimates for the Whiteblotched Skate have shown a decreasing trend between 2006–2018, from a peak of 31,747 tonnes (t) in 2006 to 20,603 t to 2018, followed by increases to 22,455 t in 2023 which is comparable with those observed in the early 2000s (Ormseth 2020, Tribuzio et al. 2023). Global population trend is estimated to be stable based on abundance data and refuge in deep water outside of current fishing activities.

The Whiteblotched Skate is demersal on continental and insular shelves and slopes at depths of 73–1,200 m (Love et al. 2021). It reaches a maximum size of 147 cm total length (TL) (Stevenson et al. 2007, Love et al. 2021). Males mature at 93 cm TL and females mature at 96 cm TL (Ebert et al. 2009, Maurer 2009). Reproduction is oviparous. Estimated female age-at-maturity is 22.5 years and maximum age is 32 years and thus, generation length is 27.3 years (Ebert et al. 2009, Maurer 2009).

The Whiteblotched Skate is a bycatch of commercial trawl, longline, and trap fisheries targeting groundfish, including Pacific Cod (Gadus macrocephalus), Alaska Pollock (Gadus chalcogramma), and Greenland Halibut (Reinhardtius hippoglossoides). It was also caught in survey trap fisheries crabs in the Okhotsk Sea (Artemenkov et al. 2022). It may be retained for the meat of the skate wings with retention rates of up to 30% in some fisheries. Post-release mortality is unknown but was 41% for deepwater Bathryaja species in southwest Atlantic trawl fisheries (Ellis et al. 2017).

In Japan, demersal trawl fisheries operate at depths of 50–500 m and effort has decreased markedly over the last three decades and is continuing to decline with fewer fishers and vessels participating in the fishery (NFMT 2017, S. Tanaka pers. comm. 2019). In Russia, the fisheries usually operate to depths of 600–800 m (Ormseth and Matta 2011). There have been occasional experimental fisheries since 2016 that fish to 2,500 m depth (I.V. Volvenko unpub. data 2019) that may constitute a threat if expanded with the interest in developing targeted skate fisheries in the North Pacific. Skate fisheries in Russia are growing: the average annual skate catch reported to official statistics has grown nearly 3-fold, from 1,650 tonnes (t) in 2004–2008, 3,510 t in 2009–2013, and 4,860 t in 2014–2018; there is no species-specific skate catch reporting (Panchenko et al. 2020). In the eastern Bering Sea, skate egg cases, including the Whiteblotched Skate, are brought to the surface by commercial demersal trawl and longline fishing vessels targeting deepwater fish including Pacific Cod and Greenland Halibut (Stevenson et al. 2019). The Whiteblotched Skate is only commercially fished in the upper region of its bathymetric range and has significant refuge at depth from fisheries.

In Japan, skates are of low value and while there is some domestic consumption, skate wings are most likely exported to the Republic of Korea (H. Ishihara pers. comm. 2019). The meat may be processed into fish meat jelly which is used in some Japanese national dishes (Orlov and Volvenko 2022). In Russia, skates were previously discarded but more recently have been landed for export of wings to China, Japan, Korea, and the British Virgin Islands (Orlov and Volvenko 2022). International demand for skates by Korea is very high and has increased skate retention with Korea a major importer of skates from around the world (Hyun-Su et al. 2013). In the Bering Sea and Aleutian Islands fisheries, 23–30% of all skates were retained from 2011–2017, with larger individuals retained due to the higher market value, and while this may include the Whiteblotched Skate, there is limited species-specific information (Ormseth 2020).

There is a Total Allowable Catch (TAC) for skates in Russian and United States waters. In Russian waters, the TAC has changed little since the 1990s and in the 2020s is 11,2000–11,3000 t (Orlov and Volvenko 2022). In the United States Bering Sea and Aleutian Islands (BSAI) regions this species is managed as a skate complex. The BSAI TAC for the complex is based on the age structured model for Alaska Skate (B. parmifera) and the combined other skate survey biomass multiplied by an assumed natural mortality rate and has varied little from 2012–2023 and in 2023 was 27,441 t (Tribuzio et al. 2023). In 2015, six areas in the BSAI region of high skate egg density were designated Habitats of Particular Concern which allows management intervention where fishing activity is deemed harmful to the habitat. The 82 square nautical miles of habitat is split into different areas at the continental shelf/slope break, and aims to protect egg cases of various skate species. Targeted fishing for skates in the Gulf of Alaska has been prohibited since 2005 (Ormseth 2021). In Japan, management measures have been implemented since the mid-1990s to control fishing effort that include Total allowable catches, seasonal closures and gear restrictions (White Paper 2019). Further research is needed on population size and trends, and life history, and catch rates should be monitored.