Decline in Size-at-Maturity of European Hake in Relation to Environmental Regimes: A Case in the Eastern Ionian Sea.

European hake, Merluccius merluccius L. 1758, is a highly valuable demersal fish species exploited in both the east Atlantic and the Mediterranean Sea. Changes in the size-at-maturity of this species have been reported in various geographic areas. Size-at-maturity is a key parameter in fishery management. Our main goal was to study the trend of the size-at-maturity of European hake in the eastern Ionian Sea (Central Mediterranean) over the last five decades. Utilizing a multi-decadal series of data for various environmental variables, we employed multivariate analyses and non-additive modeling in an attempt to identify shifts in the climatic environment of the eastern Ionian Sea and whether the maturation of the hake population could be affected by these changes. The analyses used suggest a plausible environmental regime shift in the study area in the late 1990s/early 2000s. The decrease in size-at-maturity that was detected in the last two decades may, thus, be associated with environmental changes. However, as many fish stocks already experience fishery-induced evolution, further investigation is necessary to determine whether this environmental effect is an additional stressor on a possibly already fishery-impacted population. The outcomes of this study highlight the importance of investigating the relationship between fish reproductive traits and altered environmental conditions, as the latter are generally ignored during assessments, affecting the robustness of fishery management.

Digging for historical data on the occurrence of benthic macrofaunal species in the southeastern Mediterranean.

BACKGROUND: The benthic macrofaunal biodiversity of the southeastern Mediterranean is considerably understudied compared to other Mediterranean regions. Monitoring biodiversity in this area is crucial as this region is particularly susceptible to biological invasions and temperature alteration. Historical biodiversity data could provide a useful baseline for monitoring potential changes and provide informarion to support a better understanding of the possible effects of anthropogenic activities on marine benthic communities. NEW INFORMATION: In this study, performed under the LifeWatchGreece Research Infrastructure, we present historical benthic occurrence data obtained from the sampling expedition carried out in 1933 by Adolf Steuer in the coastal area around Alexandria, Egypt, eastern Mediterranean. The occurrences were geo-referenced to more than 170 stations, mostly located in the area of Alexandria, and the nearby coasts and lakes. All records were digitized and species names were cross-checked and taxonomically updated using the World Register of Marine Species. The outcome clearly shows that such initiatives can reveal an unexpected amount of highly valuable biodiversity information for "data-poor" regions.

Value, but high costs in post-deposition data curation.

Discoverability of sequence data in primary data archives is proportional to the richness of contextual information associated with the data. Here, we describe an exercise in the improvement of contextual information surrounding sample records associated with metagenomics sequence reads available in the European Nucleotide Archive. We outline the annotation process and summarize findings of this effort aimed at increasing usability of publicly available environmental data. Furthermore, we emphasize the benefits of such an exercise and detail its costs. We conclude that such a third party annotation approach is expensive and has value as an element of curation, but should form only part of a more sustainable submitter-driven approach. Database URL: http://www.ebi.ac.uk/ena.