Are critically endangered fish back on the menu? Analysis of U.K. fisheries data suggest post-ban landings of prohibited skates in European waters

Skates (Rajidae) have been commercially exploited in Europe for hundreds of years with some species’ abundances declining dramatically during the twentieth century. In 2009 it became “prohibited for EU vessels to target, retain, tranship or land” certain species in some ICES areas, including the critically endangered common skate and the endangered white skate. To examine compliance with skate bans the official UK landings data for 2011–2014 were analysed. Surprisingly, it was found that after the ban prohibited species were still reported landed in UK ports, including 9.6 t of common skate during 2011–2014. The majority of reported landings of common and white skate were from northern UK waters and landed into northern UK ports. Although past landings could not be validated as being actual prohibited species, the landings’ patterns found reflect known abundance distributions that suggest actual landings were made, rather than sporadic occurrence across ports that would be evident if landings were solely due to systematic misidentification or data entry errors. Nevertheless, misreporting and data entry errors could not be discounted as factors contributing to the recorded landings of prohibited species. These findings raise questions about the efficacy of current systems to police skate landings to ensure prohibited species remain protected. By identifying UK ports with the highest apparent landings of prohibited species and those still landing species grouped as'skates and rays’, these results may aid authorities in allocating limited resources more effectively to reduce landings, misreporting and data errors of prohibited species, and increase species-specific landing compliance.

Are critically endangered fish back on the menu? Analysis of U.K. fisheries data suggest post-ban landings of prohibited skates in European waters

Skates (Rajidae) have been commercially exploited in Europe for hundreds of years with some species’ abundances declining dramatically during the twentieth century. In 2009 it became “prohibited for EU vessels to target, retain, tranship or land” certain species in some ICES areas, including the critically endangered common skate and the endangered white skate. To examine compliance with skate bans the official UK landings data for 2011–2014 were analysed. Surprisingly, it was found that after the ban prohibited species were still reported landed in UK ports, including 9.6 t of common skate during 2011–2014. The majority of reported landings of common and white skate were from northern UK waters and landed into northern UK ports. Although past landings could not be validated as being actual prohibited species, the landings’ patterns found reflect known abundance distributions that suggest actual landings were made, rather than sporadic occurrence across ports that would be evident if landings were solely due to systematic misidentification or data entry errors. Nevertheless, misreporting and data entry errors could not be discounted as factors contributing to the recorded landings of prohibited species. These findings raise questions about the efficacy of current systems to police skate landings to ensure prohibited species remain protected. By identifying UK ports with the highest apparent landings of prohibited species and those still landing species grouped as'skates and rays’, these results may aid authorities in allocating limited resources more effectively to reduce landings, misreporting and data errors of prohibited species, and increase species-specific landing compliance.

Population-Growth And Vertical-Distribution Of Calanus-Helgolandicus In The Celtic Sea

Calanus helgolandicus over-winters in the shallow waters (100 m) of the Celtic Sea as copepodite stages V and VI; the minimum temperature in winter is approximately 8.0°C. This over-wintering is not a true hibernation or dormacy, accompanied by a reduced metabolic state with a discontinuation of feeding and development, but more of a lowered activity, involving reduced feeding and development, with predation on available microzooplankton and detritus. Analysis of specimens from the winter population showed that copepodite stages V and VI were actively feeding and still producing and possibly liberating eggs. The absence of late nauplii and young copepodites in the water column until late March indicated that there must be a high mortality of these winter cohorts. The copepodites of the first generation appeared in April–May, the younger stages, copepodites I to III, being distributed deeper in the water column below the euphotic zone and thermocline. This distribution would contribute to amuch slower rate of development. By August the ontogenetic vertical distributions observed in the copepodites were reversed, the younger stages occuring in the warmer surface layers within the euphotic zone. Diurnal migrations were observed in the later copepodites only, the younger stages I to III either remaining deep in spring or shallow in summer. The causal mechanisms which alter the behaviour of the young copepodites remain unexplained. The development of the population of Calanus helgolandicus in 1978, reaching its peak of abundance in August, was typical for the shelf seas around U.K. as observed from Continuous Plankton Recorder data, 1958 to 1977.

Ecological And Metabolic Studies On Free-Living Nematodes From An Estuarine Mud-Flat

Nematodes from a mud-flat in the river Lynher estuary, Cornwall, U.K., have a population density ranging between 8 and 9 × 106 m−2 in the winter months, corresponding to a dry weight of 1·4 and 1·6 g m−2. They reach a peak abundance of 22·86 × 106 m−2 (3·4 g) in May. About 40 species are present, and the species composition remained seasonally stable over the period of study. Analysis of age-structure suggests that the major species have continuous asynchronous reproduction. Respiration rates of 16 species have been determined at 20 °C using Cartesian diver respirometry. For five species, respiration/body size regressions were obtained in the form log10R = log10a+b log10V, where R = respiration in nl O2 ind−1 h−1 and V = body volume in nl: Mesotheristus setosus (log10a = −0·04,b = 0·74), Sphaerolaimus hirsutus (log10a = 0·11, b = 0·68), Axonolaimus paraspinosus (log10a = 0·00, b = 0·79), Metachromadora vivipara (log10a = −0·59, b = 1·07), Praeacanthonchus punctatus (log10a = 0·00, b = 0·55). For the remaining 11 species, several animals were used in each diver and, by assuming b = 0·75, log10a′ values were calculated: Viscosia viscosa (log10a′ = 0·188), Innocuonema tentabundum (−0·012), Ptycholaimellus ponticus (−0·081), Odontophora setosa (−0·092), Sphaerolaimus balticus (−0·112), Dichromadora cephalata (−0·133), Atrochromadora microlaima (−0·142), Cylindrotheristus normandicus (−0·150), Terschellingialongicaudata (−0·170), Sabatieria pulchra (−0·197), Terschellingia communis (−0·277). These values are compared with recalculated values for other species from the literature. Annual respiration of the nematode community is 28·01 O2 m−2, equivalent to 11·2 g carbon metabolised. Community respiration is compared with figures from N. American saltmarshes. At 20 °C, a respiration of about 61 O2 m−2 year−1 g−1 wet weight of nematodes appears to be typical. Annual production is estimated to be 6·6 g C m−2. The correlation between feeding-group, body-size, habitat and the repiration rate of individual species is discussed.

Scenarios for integrated river catchment and coastal zone management

The European Water Framework Directive requires EU Member States to introduce water quality objectives for all water bodies, including coastal waters. Measures will have to be introduced if these objectives are not met, given predictions based on current trends. In this context, the estimation of future fluxes of nutrients and contaminants in the catchment, and the evaluation of policies to improve water quality in coastal zones are an essential part of river basin management plans. This paper investigates the use of scenarios for integrated catchment/coastal zone management in the Humber Estuary in the U.K. The context of this ongoing research is a European research project which aims to assist the implementation of integrated catchment and coastal zone management by analysing the response of the coastal sea to changes in fluxes of nutrients and contaminants from the catchments. The example of the Humber illustrates how scenarios focusing on water quality improvement can provide a useful tool to investigate future fluxes and evaluate policy options for a more integrated coastal/catchment management strategy.