Data set title: 
Calanus helgolandicus weekly egg production at site L4 (50°15'N, 4°13'W) in the Western English Channel from 1992 to 2012.

Name of data file:
wco_l4_calanus_1992-2012.csv

Data set creator(s) and institute(s): 
Andrea McEvoy. Plymouth Marine Laboratory.

Abstract: 
The long series of high-frequency observations of Calanus helgolandicus reproduction is unique; no other such data-set exists. This fact, combined with the extensive information on the food environment (particulates, phytoplankton species) and experimental studies on the diet and reproduction of Calanus provides an important opportunity to advance zooplankton seasonal succession modelling, and investigations of inter-annual variability at higher trophic levels.

Sampling methodology and description of analytical techniques:
Five replicates each of 5 female Calanus helgolandicus are incubated in filtered seawater for 24 hours. The females were captured during mid-morning from station L4 using a horizontal tow net and incubations initiated at mid-day. Each 2L beaker contains a plexiglass egg production tube (mesh 500 μm) and is filled with 0.2 μm filtered seawater at ambient sea temperature. At the end of the 24 hour period the eggs produced are collected and counted.

Data quality comments:
We view it as essential for all users of L4 plankton data to establish and maintain contact with the nominated current data originators as well as fully consulting the metadata. While not impinging on free data access, this ensures that this dataset is being used in the correct way, and any potential issues with the data are clarified. Furthermore, a proper dialogue with these local experts on the time series will enable, where appropriate the most recent sampling timepoints to be used.

Calanus helgolandicus egg production data file notes
The data file has been compiled from three different sources:-
* 1992 - 2005
A data file created by Angel Lopez-Urrutia on 12/12/2000. This appeared to be the most original data available for this time period. No paper copies have been found as of December 2012.
* 2006 - 2008
A data file inherited from Claudia Halsband-Lenk. There were accompanying paper records for these data.
* 2009 - 2012
Data files were recorded yearly with accompanying paper records.
The original data had not been recorded in a completely standard way throughout the time series. Therefore some deductions have had to be made:-
* 1992-1994 - only the mean number of eggs per female per day were recorded
* 1995-1997 also 2002-2005 - Mean numbers of eggs per female per day were recorded; however replicate information was also recorded. The replicate information is not in whole numbers therefore based on this (and in order for the calculation of the average egg production per female per day to make sense) it must be assumed that these numbers represent the mean number of eggs per female in each replicate.  The mean numbers of eggs per female per day are therefore based on ratios.
* 1998-2001 - Mean numbers of eggs per female per day were recorded; replicate information was also recorded. The replicate information is in whole numbers therefore based on this (and in order for the calculation of the average egg production per female per day to make sense )it must be assumed these numbers represent the number of eggs produced in each replicate and that there were 5 females in each replicate.
* 2006 onwards - Number of eggs in each replicate are recorded as are number of females per replicate. From this information the mean number of eggs per female per day has been derived. From 2009 onwards the incubation temperature and L4 temperature has also been recorded.