A giant stem-group chaetognath

Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, Timorebestia koprii gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstätte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to Amiskwia sagittiformis. Amiskwia has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that T. koprii shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in T. koprii suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today

A giant stem-group chaetognath.

Chaetognaths, with their characteristic grasping spines, are the oldest known pelagic predators, found in the lowest Cambrian (Terreneuvian). Here, we describe a large stem chaetognath, gen. et sp. nov., from the lower Cambrian Sirius Passet Lagerstätte, which exhibits lateral and caudal fins, a distinct head region with long antennae and a jaw apparatus similar to . has previously been interpreted as a total-group chaetognathiferan, as either a stem-chaetognath or gnathostomulid. We show that shares a ventral ganglion with chaetognaths to the exclusion of other animal groups, firmly placing these fossils on the chaetognath stem. The large size (up to 30 cm) and gut contents in suggest that early chaetognaths occupied a higher trophic position in pelagic food chains than today

Fishing for MSY: using “pretty good yield” ranges without impairing recruitment

Pretty good yield (PGY) is a sustainable fish yield corresponding to obtaining no less than a specified large percentage of the maximum sustainable yield (MSY). We investigated 19 European fish stocks to test the hypothesis that the 95% PGY yield range is inherently precautionary with respect to impairing recruitment. An FMSY range was calculated for each stock as the range of fishing mortalities (F) that lead to an average catch of at least 95% of MSY in long-term simulations. Further, a precautionary reference point for each stock (FP.05) was defined as the F resulting in a 5% probability of the spawning-stock biomass falling below an agreed biomass limit below which recruitment is impaired (Blim) in long-term simulations. For the majority of the stocks analysed, the upper bound of the FMSY range exceeded the estimated FP.05. However, larger fish species had higher precautionary limits to fishing mortality, and species with larger asymptotic length were less likely to have FMSY ranges impairing recruitment. Our study shows that fishing at FMSY generally is precautionary with respect to impairing recruitment for highly exploited teleost species in northern European waters, whereas the upper part of the range providing 95% of MSY is not necessarily precautionary for small- and medium-sized teleosts.</jats:p

Does recreational catch impact the TAC for commercial fisheries?

The western Baltic cod is one of the first fish stocks in Europe that, since 2013, includes recreational catches in stock assessment and fisheries management advice. In this paper, we investigate the sensitivity of the calculated commercial total allowable catch (TAC) to including recreational catches in stock assessment. Our results show that the most crucial aspect in terms of the impact on commercial TAC is the assumption on rec-reational catch dynamics relative to that of commercial fisheries used in forecast. The results were less sensitive to the information on the historical amount and age structure of recreational catch. Our study is intended to inform potential debates related to resource allocation between the commercial and recreational sectors and contribute to developing a general framework for incorporating recreational catches in fisheries management advice in ICES