(2023). Compilation of locations, larval durations and dates of spawning and settlement for coastal fishes in the Mediterranean Sea. SEANOE. https://doi.org/10.17882/91148
Compilation of locations, larval durations and dates of spawning and settlement for coastal fishes in the Mediterranean Sea
Early-life stages play a key role in the spatio-temporal dynamics of marine populations due to their highly dispersive properties, their sensitivities to environmental factors and their influences on juveniles’ replenishment. However, these stages are difficult to monitor, so that in-situ observations are scarce and disparate, preventing a good understanding of the control they exert on population dynamics.
The Mediterranean coastlines have been highly surveyed during the last decades in different sub-regions; yet no effort was made to assemble observations originating from different research projects and countries. Moreover, this sea has been exploited for centuries and is now recognized as a climate-change hotspot, so that it represents an ideal laboratory to address the role of anthropogenic pressures on marine populations. To advance our knowledge, we build an exhaustive compilation of historical data collected over the past decades up to present. From spawning to settlement, it evaluates both egg and larval stages of coastal fishes characterized by bipartite life cycles.
This compilation gathers 44 datasets from North-Western Mediterranean countries (including coastlines of Spain, France, Italy, Croatia and Montenegro) over the last three decades (1993-2021) originating from 48 data providers. We consider direct and indirect observations of early-life stages such as otoliths’ data, datasets of settlers and juveniles sampled by underwater visual census, shore seine, hand-nets or light-traps, as well as fish eggs and larvae sampled with plankton nets.
All those types of data are harmonized into a uniform dataset that informs on the periods and locations of spawning and settlement. While some sampling techniques directly provide the variables of interests, other methods require a-posteriori estimations based on growth models from the Dynamic Energy Budget (DEB) theory, using taxon-dependent parameters available in the online Add-my-Pet database. Finally, the complete database consists in several taxon, each of them being associated with dates of both spawning and settlement, as well as other information such as the pelagic larval duration, measures of uncertainties and sampling characteristics (location, depth, etc).
Statistical analyses of the consolidated database describe the overall coverage of sampling and evaluate the sampling gaps over space and time in order to guide future sampling efforts. In fact, sampling mainly occurs around marine reserves and from May to October. The general coverage of spawning and settlement is then assessed, looking at the differences between observed data (same distribution as sampling) and back-calculated data (nearly uniformly distributed over the year). Moreover, the overall taxa distribution is described, mainly represented by Sparidae. Thus, this database informs early-life traits and their variability for different coastal fish taxa in the North-Western Mediterranean in order to document their evolution in a changing world. Indeed, this database will be publicly available to help undertake future connectivity and climatic studies.
Biological oceanography
Mediterranean Sea, Spawning date, Settlement date, Pelagic Larval Duration, Early-life traits, Early-life stages, Fish larvae, Back-calculation, Dynamic Energy Budget models, Historical data, Reconstructed data
46.283801N, 34.810924S, 22.137451E, -6.514893W
Metadata of the database
The consolidated dataset consists of 119639 entries (i.e. rows of the database), standing for one or multiple individuals (i.e. eggs, larvae, settlers or juveniles), each of them being characterized by 30 variables (i.e. columns of the database); their naming convention and meaning are described here.
- Project: Project’s name or data source.
- Ecoregion: Name of the ecoregion, following Spalding et al., 2007, in which sampling took place (Adriatic Sea, Alboran Sea, Ionian Sea, Western Mediterranean).
- Site: Name of the sampling site used by the data providers.
- Latitude: Latitude of the site (decimal degrees - °).
- Longitude: Longitude of the site (decimal degrees - °).
- CoordinatesType: specify the event, e.g. spawning or settlement, to which geographical coordinates are associated (spawning coordinates, settlement coordinates).
- GeneralSamplingTechnique: General category of tool or method used to sample (Beam trawl, Bongo net, Epibenthic trawl, Fixed plankton net, Hand net, Light trap, Multiple opening / closing plankton net, Neuston 3 nets, Ring net, Shore seine, Underwater visual census).
- SpecificSamplingTechnique: Specific characteristic of the sampling tool or method used to sample (examples: CARE light-traps, 40 cm diameter Bongo net).
- SamplingDepth: Depth at which the sampling was performed (meters - m), that is NOT the total depth of the site.
- SiteMeasureValue: Value measuring the sampling effort (per unit of area or of volume or of time or a number of gears deployed).
- SiteMeasureUnit: Unit evaluating the sampling effort, depending on the method used (square meters - m2, cubic meters - m3, hours - h, number of traps – trap, number of trap per night - trap.night-1).
- SamplingDate: Date of sampling (ISO 8601 format - yyyy-mm-dd).
- Replicate: Number of replicates for a site (1 indicates no replicate).
- Family: Taxonomic name of the family.
- Genus: Taxonomic name of the genius.
- Species: Taxonomic name of the species.
- NumberOfIndividual: Number of individuals sampled for one entry (N).
- DensityValue: Value measuring the density of individuals per unit of area, volume, time or gear.
- DensityUnit: Unit evaluating the density of individuals (number of individuals per square meters - N.m-2, number of individuals per cubic meters - N.m-3, number of individuals per hour - N.h-1, number of individuals per trap - N.trap-1, number of individuals per trap per night - N.night.trap-1).
- Comments: Various comments on the observation.
- SamplingLength: Total length of the individuals at sampling (millimeters - mm).
- Stage: Stage of the individuals at sampling (Egg - Small larva, Larva, Settler, Juvenile).
- SpawningDate_mean: Mean spawning date (ISO 8601 format - yyyy-mm-dd).
- SpawningDate_std: Standard deviation of the spawning date (days – d).
- SpawningDetermination: Methodology used to determine the spawning date (otolithometry, sampling date, back-calculation species-based, back-calculation genus-based).
- PLD_mean: Mean Pelagic Larval Duration, which is computed as the time difference between spawning and settlement dates (days – d).
- PLD_std: Standard deviation of the Pelagic Larval Duration (days – d).
- SettlementDate_mean: Mean settlement date (ISO 8601 format - yyyy-mm-dd).
- SettlementDate_mean: Standard deviation of the settlement date (days – d).
- SettlementDetermination: Methodology used to determine the settlement date (otolithometry, sampling date, back-calculation species-based, back-calculation genus-based).
NA stands for “Non Available” and represents missing data.
All data follow the quality code 1 of SeaDataNet Thesaurus L20 (SeaDataNet measurand qualifier flags), except missing data NA associated to code 9 (https://www.seadatanet.org/).
Reference:
Spalding, M. D., Fox, H. E., Allen, G. R., Davidson, N., Ferdaña, Z. A., Finlayson, M., Halpern, B. S., Jorge, M. A., Lombana, A., Lourie, S. A., Martin, K. D., McManus, E., Molnar, J., Recchia, C. A., and Robertson, J. (2007). “Marine Ecoregions of the World: A Bioregionalization of Coastal and Shelf Areas”. In: BioScience 57.7, pp. 573–583. doi: 10.1641/B570707.
Irisson Jean-Olivier
