Ms. Joana Costa Vilhena de Bessa Campos

Address: NIOZ - Royal Netherlands Institute for Sea Research, Texel, Nederland; Centro Interdisciplinar de Investigação Marinha e Ambiental. Porto, Portugal.
Curriculum vitae
Specialization: Applied Ecology
Project: The role of the brown shrimp in the functioning of coastal estuaries

The role of brown shrimp Crangon crangon L. in the functioning of the ecosystem in coastal European estuaries with an emphasis on latitudinal trends

The common or brown shrimp Crangon crangon L. is a common species on especially sandy and muddy substratum in estuarine and coastal areas with a wide distribution along the coast of continental Europe. Originally, its main distributional range was considered to be restricted between 45 and 57 NL (Tiews 1970), however recent information indicate that its presence extends from Iceland and the White Sea in the north until Morocco in the south and the Adriatic in the east (Gunnarsson, unpubl.). Over almost its entire range of distribution, the species is very abundant and hence must form an important component of the ecosystem. On the one hand C. crangon is an important predator on various benthic species such as bivalve spat and juvenile fishes like plaice (Van der Veer, Ellis et al. 1997; Van der Veer et al. 1998), on the other hand C. crangon forms an extensive food source for a large range of predators such as fishes and wading birds. Therefore, shrimps will play a crucial role in the ecosystem.

Review on latitudinal trends in the life history strategy of the brown shrimp Crangon crangon (L.)

This review aims to update and extend the synopsis by Tiews (1970) on the biology and fisheries of Crangon crangon (L.). Its wide distributional range along the European coast from the White Sea in the North until the Black Sea in the Mediterranean, reflects the fact that C. crangon can cope with a wide range of temperature and salinity conditions. In combination with its migratory capacity, this explains its presence over such a wide distributional range. Present knowledge suggests that the limiting factor at the northern cold water edge of its distribution is formed by egg and larval development, and at the southern warm water edge, by maintenance costs. No information is available about the genetic population structure, but patterns in isoenzymes and in morphometric characters suggests the existence of various subpopulations. Over its distributional range, especially along the North Atlantic coast clear patterns in life history parameters are observed, most likely reflecting trends in temperature conditions. Due to its in general high abundance, the common shrimp forms a key component in the functioning of coastal shallow ecosystems, however at present it is unclear whether the population dynamics of the species is top down or bottom up controlled. On the one hand C. crangon is an opportunistic feeder with a wide prey spectrum but it remains to be solved whether growth conditions are optimal and only determined by prevailing water temperatures, or whether food limitation is a regulating mechanism. On the other hand top down control by predation cannot be excluded since C. crangon is also an important food item for a variety of predators especially fish species. There are strong indications that predation by C. crangon might regulate some of their prey species. Topics for further research include
  1. the analysis of the genetic population structure by means of molecular tools
  2. the study of growth conditions in relation to latitude
  3. the application of Dynamic Energy Budgets for the analysis in terms of energy of the various trade-offs, including growth versus reproduction; and
  4. the analysis of the mechanisms determining recruitment, especially whether top down or bottom up control is occurring.

Population zoogeography of brown shrimp along its distributional range based on morphometric characters

Morphometric characteristics have proven to be applicable to identify subpopulation structure in the common shrimp Crangon crangon L. at a local scale (100 km) around the U.K. In this study C. crangon populations were sampled over the whole distributional range from northern Norway until the Mediterranean and the Black Sea with the goal to test whether the same method could be applied to identify subpopulation structure at a much large scale (1000 km). Spatial variability in morphometic characters was determined by sampling of 26 stations spread out over the distributional range. In addition, temporal variability was established by sampling 4 stations on a monthly basis (Bodo, Norway; Wadden Sea, The Netherlands; Lima and Minho, Portugal). In contrast to expectations strong temporal variability was observed at all four locations. As a consequence, despite strong spatial differences and patterns, no clear subpopulation structure could be identified, except for a difference between East Atlantic and Mediterranean populations. Variability in morphometric characters seems to be not sensitive enough to identify detailed subpopulation structure at a large scale.

Phylogeography of the common shrimp, Crangon crangon (L.) in European waters

Since morphometrics proved to be an unreliable method to establish the population structure of Crangon crangon, current population structure was studied by sequencing and comparing the neutral gene Cytochrome Oxidase subunit I. An extensive biobank was constructed of samples of the common shrimp Crangon crangon (L.) over its entire range of distribution along the European coast from Norway to the Black Sea. Current population structure was studied by In contrast with the morphometric approach less subpopulations could be identified, which means that most of the morphometric differences between populations could be identified as phenotypical plasticity. The genetic markers showed the following population structure: Eastern Atlantic Ocean, western Mediterranean Sea, Adriatic Sea and Black Sea. Apparently, the Strait of Gibraltar and the Bosporus provide absolute barriers for gene flow of adult shrimp and of the pelagic larvae. We measured large genetic variation within the Mediterranean population; relatively little variation within the Adriatic and Black Sea populations, and even less variation in the Atlantic population. A molecular clock was applied to determine the biogeographic history of Crangon crangon. Results clearly show that a shrimp population from the Western Mediterranean colonized the Adriatic Sea, Black Sea and North Eastern Atlantic. Data also suggest that the Baltic Sea was colonized from the Atlantic (8000 years ago). The catch of Crangon crangon at the southern coast of Iceland has not been reported before and probably results from a new very recent re-colonization event.

Growth of Crangon crangon: does counter-gradient growth compensation occur?

Laboratory experiments were carried out to determine maximum possible growth in relation to water temperature. Experiments were carried out at different locations over the distributional range of C. crangon (Bodo Norway, Wadden Sea, The Netherlands, Minho, Portugal to analyse whether counter-gradient growth compensation does occur.

Is the shrimp Crangon crangon food-limited over its distributional range?

Spatial and temporal variability in energy flow into growth and reproduction of C. crangon in the field was analysed at various locations over its distributional range of the Eastern Atlantic genetic subpopulation by means of Dynamic Energy budgets (DEB models). First, DEB parameters were estimated for C. crangon. Next, food conditions for the various locations were reconstructed from the observed growth patterns and water temperature conditions. Preliminary results suggest that growth, reproduction and maximum age varied with latitude. Growth conditions were not always optimal and appeared to be density-dependent and food limited in some areas and time periods.

A 40-year study of climatic and population regulation of common shrimp Crangon crangon (Crustacea: Caridea) in the western Wadden Sea, The Netherlands

The results of a 40-year study of the population dynamics of the common shrimp, Crangon crangon, in the western Wadden Sea by means of fyke net catches are presented. Population size varied seasonally, with maximum abundance occurring in early autumn at the completion of annual recruitment. The number of recruits changed greatly between years, and was correlated with a number of physical and biotic variables

Synthesis: Role of brown shrimp in the ecosystem over a latitudinal gradient

The role of brown shrimp Crangon crangon in the functioning of the ecosystems in coastal European estuaries over a latitudinal gradient is analyzed for the East Atlantic subpopulation. Based on existing literature on the brown shrimp its prey items and its predators, trends in abundance, their predation pressure and their importance as prey are identified. These aspects are discussed in relation to the total energy flow from the benthic system into the epibenthic predators to evaluate the importance of the role of shrimps in the functioning of estuarine systems. Finally, the observed trends are discussed in the light of factors regulating the brown shrimp population. The northern cold water edge of the distribution is most likely determined by the impact of low water temperatures in summer on larval development. Metabolic stress by high summer temperatures appears to define the warmer water system in the southern edge of the distribution. In all areas juvenile shrimps were predators on bivalve spat. In all areas bivalve recruitment coincided and overlapped with the growing season of juvenile shrimps. The impact of predation appears to be dependent on prevailing temperature conditions. At low temperatures, impact of shrimp predation on bivalve recruitment appears to be insignificant. With increasing temperature predation by shrimps became a significant source of mortality of bivalve spat. Top-down control by shrimp predation on bivalve species appears to become more important towards the southern edge of the distribution of C. crangon.

2009/09/10:45 Joana Campos: defense thesis in the Aula

10:45 welcome by Prof. Dr. Herman Verhoef
(Rector Magnificus)
promotor Prof. Dr. Bas Kooijman;
copromotor Dr. Henk van der Veer
10:45 Introduction by Joana Campos
10:55 Dr. Peter Henderson Professor at the Department of Zoology, University of Oxford
11:05 Dr. Chris Klok Team manager Functional Biodiversity, Alterra
11:15 Dr. Adriaan Rijnsdorp Professor Aquaculture and fisheries, Wageningen University
11:25 Dr. Jaap van der Meer Professor Population dynamics, VU University Amsterdam
11:35 Dr. Bob Kooi Associate professor Bifurcation Analysis, VU University Amsterdam
11:45 end of defence; start of closed meeting
12:10 ceremony
12:20 end of ceremony; lunch in the Basket

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