Search

Policies aiming to restore ecosystems, achieve thriving fisheries and reverse biodiversity loss require knowledge of their former status and long‐term variation. As quantitative fish data is typically only available for recent decades long after changes may have occurred, a greater use of qualitative sources has been encouraged in marine historical ecology. We examined diverse historical information (including maritime history, fisheries reports, naturalists' accounts, recipes, nautical charts and newspapers) across a multi‐century time span (13th–20th century) for a wide range of species to document their long‐term trajectories in an understudied Northeast Atlantic ecosystem (Irish Sea coast of Wales). We find strong evidence of the loss of both a pelagic fishery for herring, which was of fundamental socio‐ecological importance since at least the 13th century, and the loss of significant multi‐species demersal and intertidal fisheries. Local, commercial and/or functional extinction has occurred for taxa spanning a wide range of diversity (crustacean, elasmobranchs, sturgeon, and teleosts), body size and ecological role, suggesting far‐reaching changes to food webs. This raises fundamental questions about the present‐day health and integrity of this coastal ecosystem and the long‐term viability of current fisheries which depend on a few shellfish species. Our century‐scale synthesis of qualitative data for multiple taxa allows the collective breadth of losses to be fully appreciated and may reduce the risk of 'shifting baselines'. Restoration to historical baselines may not be achievable, but our findings provide evidence of long‐term change relevant to policies for recovery, and prevention of further decline of fishes, fisheries and ecosystems. [ABSTRACT FROM AUTHOR]

A 2019 photograph of a blue skate Dipturus batis caught in Welsh waters is the first species‐specific evidence of the "common skate" complex occurring in its former range in the main body of the Irish Sea over four decades after it was considered to have been extirpated there. This possible precursor to recolonisation of former range adds to growing evidence for the recovery of skate species in the North Atlantic and highlights the valuable role of anglers and social media as a complement to important, yet costly, scientific surveys when monitoring rare fishes. [ABSTRACT FROM AUTHOR]

The extinction risk of sharks, rays and chimaeras is higher than that for most other vertebrates due to low intrinsic population growth rates of many species and the fishing intensity they face. The Arabian Sea and adjacent waters border some of the most important chondrichthyan fishing and trading nations globally, yet there has been no previous attempt to assess the conservation status of species occurring here. Using IUCN Red List of Threatened Species Categories and Criteria and their guidelines for application at the regional level, we present the first assessment of extinction risk for 153 species of sharks, rays and chimaeras. Results indicate that this region, home to 15% of described chondrichthyans including 30 endemic species, has some of the most threatened chondrichthyan populations in the world. Seventy‐eight species (50.9%) were assessed as threatened (Critically Endangered, Endangered or Vulnerable), and 27 species (17.6%) as Near Threatened. Twenty‐nine species (19%) were Data Deficient with insufficient information to assess their status. Chondrichthyan populations have significantly declined due to largely uncontrolled and unregulated fisheries combined with habitat degradation. Further, there is limited political will and national and regional capacities to assess, manage, conserve or rebuild stocks. Outside the few deepsea locations that are lightly exploited, the prognosis for the recovery of most species is poor in the near‐absence of management. Concerted national and regional management measures are urgently needed to ensure extinctions are avoided, the sustainability of more productive species is secured, and to avoid the continued thinning of the regional food security portfolio. [ABSTRACT FROM AUTHOR]

Kuwait’s waters are one of only two locations where the smoothtooth blacktip shark Carcharhinus leiodon is known to occur. Concentrations of 11 trace elements were analysed in five juvenile and two adult specimens of this coastal predator. Concentrations of lead in muscle increased with length, whilst manganese concentration decreased. Arsenic concentrations in muscle were among the highest reported in elasmobranchs, and the concentration in the liver increased significantly in relation to length. In comparison to published literature, concentrations of manganese (liver), lead (muscle) and iron (muscle and liver) were high. Mercury concentrations in the muscle exceeded European Food Safety Authority limits and were among the highest reported in any elasmobranch. Concentrations of selenium, which may inhibit mercury toxicity, were also high. These results and previous studies indicate that potentially hazardous levels of mercury and other contaminants may occur in sharks in this region, adding further stressors to these vulnerable populations. [ABSTRACT FROM AUTHOR]

Historical sources can provide important data for modern-day threatened species conservation, such as identifying formerly important habitat on which to focus recovery efforts. Here we reveal unique written archival material from the 1740s that provides reliable first-hand observations of the Critically Endangered angel shark Squatina squatina , extending modern knowledge of this species in Welsh waters back by over half a century. These sources clearly identify small-scale and spatially explicit areas of abundance (including of juveniles) around specific reefs that align with more recent data, further strengthening evidence that these areas are of long-term importance that should be prioritised for the global conservation of this species, which has become extinct across much of its former range. These contemporary sources also describe fisheries for angel shark and high desirability, economic value and export trade of their meat, which could suggest that population declines of this intrinsically vulnerable species commenced centuries before modern science detected this. These unique observations highlight the value that historical material can provide in prioritising resource-limited conservation efforts, as well as helping to reframe our temporal understanding of elasmobranch fish declines. • 18th century notes record explicit locations important for a now-threatened shark. • These align with more recent records, highlighting importance of area. • Historical archives can provide long-term knowledge context for conservation. [ABSTRACT FROM AUTHOR]

Commercial fishing vessels can be a cost-effective alternative to research vessels for performing towed gear fishery-independent surveys, if catch rates are comparable among commercial vessels and with research vessels. A parallel fishing experiment was conducted off the coast of Wales, United Kingdom, to compare the king scallop (Pecten maximus) catch rates of three commercial vessels using commercial dredges and a research vessel using two types of scientifically modified dredges. The scientific dredges are currently used in the fishery-independent survey of local scallop populations. Size-structured scallop catch-per-unit-effort (CPUE) was compared among vessel-gear combinations. Two similarly sized commercial vessels had generally similar CPUEs, however there were some significant differences with scallop size. A smaller commercial vessel had significantly lower CPUEs for a broad range of scallop sizes. The research vessel dredges had significantly higher CPUE for smaller scallops than the commercial vessels. Vessel size is likely to be driving the differences among commercial vessels and belly ring size is likely to be driving differences among research and commercial dredges. These findings highlight commercial vessel CPUE should not be assumed the same, whilst also showing that vessel size may be the best indicator of catch rate similarity. These results also highlight that changing the fishery-independent vessel and gear to the commercial options trialled here would result in a considerable loss of information about the smaller scallops in the population. These findings will be of interest to fishery scientists or managers using multiple vessels, or considering a change of vessels, for fishery-independent surveys. • Research vessel caught significantly more small scallops than commercial vessels. • Smallest commercial vessel caught significantly less scallops at greater depths. • Two commercial vessels of similar size and engine power had similar catch rates. • Differences in catch rates likely driven by belly ring size and vessel size. • Vessel catch rates should not be assumed to be directly comparable. [ABSTRACT FROM AUTHOR]