DFO Maritimes Research Vessel Trawl Surveys Fish Observations

This page has been Archived. The new versions of the datasets can be found at: Maritimes Summer Research Vessel Surveys http://ipt.iobis.org/obiscanada/resource?r=maritimes_summer_rv_surveys Maritimes Spring Research Vessel Surveys http://ipt.iobis.org/obiscanada/resource?r=maritimes_spring_rv_surveys Maritimes Fall Research Vessel Surveys http://ipt.iobis.org/obiscanada/resource?r=maritimes_fall_rv_surveys Maritimes 4VSW Research Vessel Surveys http://ipt.iobis.org/obiscanada/resource?r=maritimes_4vsw_rv_surveys This is the OBIS-formatted view of the Canadian Department of Fisheries and Oceans (DFO) Maritimes Research Vessel Trawl Surveys. This data is created using a Structured Query Language (SQL) program run against the DFO production database. Refer to the project section for more information about the surveys. This OBIS product reports the abundance and weight of demersal fish species captured by a variety of trawl gear and vessels. 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. Strata statistics required to derive stratified random estimates of catch abundance and biomass can be found on the OBISCanada website http://obiscanada.marinebiodiversity.ca/database/dfo-maritimes-survey-strata-statistics).