RRS Challenger CH4/81

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Challenger (74CH)
Cruise identifierCH4/81
Cruise period1981-03-03 — 1981-03-18
Port of departureArdrossan, United Kingdom
Port of returnBarry, United Kingdom
Objectives1. To compare the vertical distributions and diurnal migrations of the developmental stages (including nauplii) of Calanus finmarchicus, Thysanoess longicaudata and Sagitta maxima from the open ocean with Calanus helgolandicus, Nyctiphanes couchi and Sagitta elegans from the Celtic Sea. (The choice of sites is determined by (a) the requirement to obtain the sets of species uncontaminated by each other; this is especially the case with the copepods C. finmarchicus and C. helgolandicus. (b) to maintain the comparative ecological investigations with work carried out at Ocean Weather Station "India" from 1971 to 75 and Celtic Sea from 1977 to 1981).
2. To measure the feeding rates of all species used in the experimental programme under ambient conditions.
3. To obtain fresh material for length/dry weight measurements and to deep freeze material for the determination of carbon, nitrogen, ash and calorific content, of all species used in the experimental programme.
4. At the two sites: to investigate other biotic conditions (chlorophyll, total suspended matter, organic matter and phytoplankton) and hydrography.
5. To obtain eggs from C. finmarchicus and C. helgolandicus for studies on their chromosomes.
Chief scientistDouglas Hamilton (University of Bristol Geology Department)
Cruise reportRRS Challenger CH4/81 cruise report ch4_81.pdf (0.15 MB) 
Ocean/sea areas 
GeneralNorth East Atlantic Ocean (limit 40W)
SpecificW. Approaches
Track chartsRRS Challenger CH4/81 cruise track — trk2860.html
Physical oceanography 
Current metersQuantity: number of deployments = 10
Description: 190 hours
Biology and fisheries 
Eggs and larvaeDescription: eggs from C. firmarchicus and C. helgolandicus preserved.
Geology and geophysics 
GrabQuantity: number of deployments = 5
Single-beam echosoundingQuantity: track kilometres = 555
Long/short range side scan sonarQuantity: track kilometres = 555