Zooplankton Group

Current Research What's New? Members Publications

Ethos statement

The marine pelagic ecosystem has a profound impact on humankind and the biosphere, and provides fundamental insight into biological questions. Our research aims to improve how we quantify and track the role of zooplankton and its change, but also to answer broader science questions, using marine plankton and nekton as the best available models / taxa to test hypotheses. We use a range of approaches such as laboratory experimentation, meta-analysis, conceptualisation and mathematical models.

Some current research topics

The majority of ectothermics follow the Temperature-Size Rule (TSR), exhibiting smaller body sizes at warmer temperatures at any particular life stage. Understanding the mechanism that drives the TSR is vital in order to make predictions of the future effect of increasing temeratures (through climate change) on species body size. It is believed that a mismatch in the temperature-dependence of growth (increase in mass) and development (increase in life-stage) rates leads to the TSR phenomenon. We aim to test this theory by modelling data from the literature and by experimental methods.

We are currently examining the effect of temperature on growth and development rate on a model organism (Artemia salina).

Adult copepod sex ratios are often highly skewed, with females commonly outnumbering males. Previous studies, using indirect methods, have shown species, stage and sex specific differences in copepod mortality and that predation or differences in physiological longevity are the cause. It is important to determine the factors that can affect sex ratio in adult copepods, because a strong sex-ratio skew can control population growth when food abundance is high. Our aim is to understand how predation and physiological mortality both contribute to skewed sex ratios and to directly investigate stage-specific mortality using a range of predators, examining the influence of prey size and behaviour.

We are currently performing Aurelia aurita (scyphozoan jellyfish) predation experiments on male and female adult copepods. Aurelia aurita are being supplied by the aquarium at  the Horniman Museum, London. A monthly programme of plankton sampling is also being performed in Southampton water to examine the sex-ratios of copepods in juvenile and adult stages. Predators (jellyfish and chaetognaths) are sampled concurrently for gut content analysis to determine ingestion rates on the copepods by species, stage and sex.

What's New?

June 2010

kreisel Aurelia aurita predation experiments on different stages and sexes of Acartia tonsa have started on a bi-weekly basis.

Jack has set up a series of water baths to study the growth and development of Artemia salina at different temperatures. 


A. Hirst 
Dr. Andrew Hirst
Senior Lecturer
a.g.hirst("at" sign)
T. Balfour
Tania FitzGeorge-Balfour (née Smith)
Postdoctoral Researcher
t.fitzgeorge-balfour("at" sign)
J. Forster
Jack Forster
Post-graduate Student
j.forster("at" sign)

Recent Publication Highlights

Yebra L, Harris RP, Head EJH, Yahayaev I, Harris LR, Hirst AG (2009) Mesoscale physical variability affects zooplankton production in the Labrador Sea. Deep Sea Research I 56(5): 703-715

Harris RP, Yebra L, Guilhaumon F, Conway DVP, Hirst AG (2008) Temperature effects on Calanus helgolandicus (Copepoda: Calanoida) development time and egg production. Journal of Plankton Research 31: 31-44

Hirst AG, Ward P (2008) Spring mortality of the cyclopoid copepod Oithona similis in polar waters. Marine Ecology Progress Series 372: 169-180

Kiørboe T, Hirst AG. (2008) Optimal development time in marine copepods. Marine Ecology Progress Series 367: 15-22

Atkinson D, Hirst AG (2007) Life histories and body size. Book Chapter: Body size and the organisation and function of aquatic ecosystems. Eds. A Hildrew, D Raffaelli & R Edmonds-Brown. Oxford University Press.

Cook KB, Bunker A, Hay S, Hirst AG, Speirs DC (2007) Naupliar development times and survival of the copepods Calanus helgolandicus and Calanus finmarchicus in relation to food and temperature. Journal of Plankton Research 29: 757-767

Fielding S, Ward P, Pollard RT, Seeyave S, Read S, Hughes JA, Smith T, Castellani C (2007). Community structure and grazing impact of mesozooplankton during late spring/early summer 2004/2005 in the vicinity of the Crozet Islands (Southern Ocean). Deep-Sea research II 54: 2106-2125

Fileman E, Smith T, Harris RP, (2007). Grazing by Calanus helgolandicus and Para-Pseudocalanus spp. on phytoplankton and protozooplankton during the spring bloom in the Celtic Sea. Journal of Experimental Marine Biology and Ecology 348: 70-84

Hirst AG, Bonnet D, Harris RP (2007) Seasonal dynamics and mortality rates of Calanus helgolandicus over two years at a station in the English Channel. Marine Ecology Progress Series 340: 189-205

Kimmerer WJ, Hirst AG, Hopcroft RR, McKinnon AD (2007) Estimating juvenile copepod growth rates: corrections, inter-comparisons and recommendations. Marine Ecology Progress Series 336: 187-202.

Ward P, Hirst AG (2007) Oithona similis in a high latitude ecosystem: abundance, distribution and temperature limitation of fecundity rates in a sac spawning copepod. Marine Biology 151: 1099-1110.

Hirst AG, Bunker AJ (2003) Growth of marine planktonic copepods: Global rates and patterns in relation to chlorophyll a, temperature, and body weight. Limnology and Oceanography 48: 1988-2010.

Hirst AG, Kiørboe T (2002) Mortality of marine planktonic copepods: global rates and patterns. Marine Ecology Progress Series 230: 195-209.