Canadian DFO Invertebrate Trawl Surveys


The dataset compiles Canadian Department of Fisheries and Oceans (DFO) Maritimes Research Vessel Trawl Surveys and reports the abundance and weight of invertebrate species captured by a variety of trawl gear and vessels. The data are available at OBIS. The OBIS compiled data includes species name, individual count, lat/lon, and some environmental correlates like depth and salinity. 

Dataset Location: OBIS DFO Maritimes Invertebrate Trawl Surveys

Direct Download: OBIS DFO Maritimes Invertebrate Trawl Surveys

Related Datasets: Canadian DFO Fish Trawl Surveys

Site Location: Northeastern US Coast and Canadian Coast

Site(s) Georeferenced: Yes

Timespan: 1999 - 2013

Sampling Frequency: irregular

Data Collection Summary / Methods: Invertebrate sampling was first coordinated with the existing Fish Trawl Surveys in 1999. Target invertebrate species include lobster, several species of crab, and several groups of echinoderms.

From OBIS metadata - "Catch data appear in the ""individualcount"" and ""observedweight"" OBIS fields (DwC dynamic properties field) and have been normalised for distance towed. The swept area of each tow can be found in the ""samplesize"" field of the OBIS schema (DwC dynamic properties field). Care should be taken when using multiple types of gear since the catchability of different fish species varies from gear to gear. The OBIS field ""locality"" contains the DFO stratum number where each tow was conducted. The OBIS field ""collectioncode"" identifies which survey series each data record comes from." 

Data collected: OBIS data schema: species name, individual count, date, location, temperature, depth, salinity, nitrogen, oxygen, silicate.

Point Fields: InstitutionCode, CatalogNumber, Citation, FieldNumber, Collector, YearCollected, MonthCollected, DayCollected, TimeOfDay, StartYearCollected, StartMonthCollected, StartDayCollected, StartTimeOfDay, EndYearCollected, EndMonthCollected, EndDayCollected, EndTimeOfDay, ContinentOcean, Locality, StartLatitude, StartLongitude, EndLatitude, EndLongitude, Latitude, Longitude, MinimumDepth, MaximumDepth, Temperature, SampleSize, ScientificName, Kingdom, Phylum, Class, Order, Family, Genus, Species, ObservedWeight, ObservedIndividualCount.

Known Issues: Trawl gear and length can impact the species and abundance recorded. Individual counts have been standardlized for distance towed, though gear details requires a direct request to the data provider.

Best Practices: Strata statistics required to derive stratified random estimates of catch abundance and biomass can be found on the OBISCanada website or upon request. Gear and its description can also be provided upon request.

Conditions for use: 'freely available' and 'open-access' as per OBIS:

Canadian scientific ministries and intitutions operate under an 'open-data' policy:

Citation/ Distributing Author: DFO, 2014. DFO Maritimes Research Vessel Trawl Surveys Invertebrate observations. Version 6 In OBIS Canada Digital Collections. Bedford Institute of Oceanography, Dartmouth, NS, Canada. Published by OBIS, Digital Accessed on –INSERT DATE

Supplemental resources: OBIS Canada -

Canada DFO -

Related Publictions -

Tremblay M.J., G.A.P. Black and R.M. Branton. 2007. The distribution of common decapod crustaceans and other invertebrates recorded in annual ecosystem surveys of the Scotian Shelf 1999-2006. Can. Tech. Rep. Fish. Aquat. Sci. XXXX: iii + XX p.

Available via the EcoData Retriever: No

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