Potential strategies for managing tilapia production in the context of global warming: temperature effects & adaptation to salinity JF Baroiller,

Transcription

1 Potential strategies for managing tilapia production in the context of global warming: temperature effects & adaptation to salinity JF Baroiller, Cirad-INTREPID CLIMATE CHANGE CONSTRAINTS ON AGRICULTURE, FRENCH-ISRAELI COLLOQUIUM, 17-19/3/2014

2 Food production statistics for major commodities (FAOStat & FishStat) For several decades aquaculture has been the fastest growing food production sector in the world Food fish plays an important role in human nutrition & global food supply Hall et al., 2011

3 World aquaculture production by continent in (land areas are adjusted proportionally to production volumes) Two-thirds of global aquaculture production Hall et al., 2011

4 Aquaculture growth relied heavily on fishmeal & fish oil Fisheries Aquaculture 1/3 maximum 80 Mt/year 2/3 fishmonger 1/3 Aquaculture converts 65% of the fishmeal 64 Mt in 2011 (aquaculture growth: 8%/year since the late 1970s) 17 kg/person/yr

5 Tacon et al., 2010

6 Potential major impacts of climate change on aquaculture & consequences Climate change Ocean currents Temperature rise Sea level rise Rainfall amount & seasonal patterns River flows Storm severity & frequency Waves surges Acidification Algal blooms Enhanced stratification Redrawn from De Silva, S.S., 2012 Aquaculture Direct impacts Indirect impacts Production & yield Inability to farm Increased disease susceptibility New diseases Calcification changes Physical damage Changes in spawning patterns Fish kills (from upwellings) Economic Viability Social impacts Fishmeal/fish oil supplies Trash fish supplies Ingredient price escalations Loss of farming sites Acidification impacts/molluscs

7 Vulnerability - Aquaculture More vulnerable Freshwater Shallow water Wild fry/seed collection Long culture cycle Narrow tolerance range High trophic level species Less vulnerable Marine water Deep water Hatchery production Short culture cycle Wide tolerance range Low trophic level species Tilapias Fresh-Marine water Shallow-Deep water Hatchery Pdtion Short culture cycle Wide tolerance range Low trophic level species From Pullin & White, 2011 Tilapia aquaculture has a relatively low vulnerability to the effects of climate change; some benefits can even be expected from warmer temperatures & higher rainfall

8 In the context of Climate Change what could be the best fish species for aquaculture? Aquaculture will have to place increased reliance on species, stocks/strains that can live & perform adequately in a wide range of environments. For ecological and economic reasons, this will favor the use of fish that feed at lower trophic levels and have relatively short production cycles, such as tilapia. In warmer waters of variable quality, air-breathing species, such as catfish, will have increased potential, especially in aquaculture.

9 Production of the 3 main aquaculture fish species (excepting carps) Production (tonnes/year) Asian Catfish Tilapia Salmon

10 Building climate-resilient aquaculture? Identify/develop/conserve species/strains able to tolerate the higher temperatures and salinities that are likely to impact aquaculture due to climate change. Research should focus on the evolution of physiological and genetic adaptations to osmotic and thermal stress in aquatic animals. Studies on the effects of high temperatures, and salinities

11 D: Density GR: Growth Rate T: Temperature ph H: Hypoxia 70 sensitive species (61 thermosensitive sp).

12 In tilapias, high temperature can influence the sex-ratios Sex-ratio (%) At the population level Temperature ( C) Masculinisation by high temperatures (T > 32 C) Very Stable sex ratios for a given couple & temperature But Variable progeny sensitivity (0-100%) P1 P2 P3 P4 P5 At the inter-individual level (Diallel crossings 5 x 5) 35 Important parental effects (both paternal & maternal influences) (from Baroiller et al., 95, 98, 00) Male gain (%) A B C D E 1 Females Males

13 O. niloticus distribution area Egypt, Lake Manzala Ethiopia Temperature-induced sex differentiation in 6 natural populations of Nile tilapia adapted to different thermal environments Lake Metahara (Hot hydrothermal springs; T C up to C) L. Koka (Cold highland lake) Ghana, Lake Volta (large seasonal variations) Kenya Lake Turkana Lake Victoria Breeder collection Control (27-28 C) Nb of Progenies Sex-ratio (M%) Temperature Treatment (36 C) Nb of Progenies Sex-ratio (M%) * * * * 28 C 36 C Temp. Treatments * * Sexing From Bezault et al., 07; Baroiller et al., 2009

14 Temperature influences genes during tilapia gonadal sex differentiation DPF UNDIFFERENTIATED FATE DECISION DIFFERENTIATION Hatching First feeding Few PGC Efferent ducts PGC mitosis Male XY Trigger of Masculinisation? sf1 amh wt1 sox9 Androgens igf1 Testes dmrt1 Bipotential Gonad dmrt1 amh? sox9 Masculinizing temperature treatment? cyp19a1a foxl2 Female XX rspo1 fst wnt4 dax1 cyp19a1a foxl2 estrogens igf1 Ovarian cavity Ovaires Baroiller et al., 2009 Few PGC PGC mitosis PGC meiosis

15 Correlation between the masculinising effect of temperature treatment and the decrease of aromatase expression Sex Ratios (%) Cyp19a1a Gene Expression 100% 80% 60% 40% FEMALES 20% Males 0% 27 C 35 C A Progeny MALES 27 C 35 C B Progeny A Progeny (XX) B 27 ƒ C 35 ƒ C D Cotta et al., 2001a; Poonlapdecha et al., unpub. Temperature 36 C Testes dmrt1 amh cyp19a1a foxl2 Ovaires Aromatase is a good marker of thermosensitivity. It can be used to characterize thermosensitivity of wild populations

16 Salinization of inland water following the rise of the ocean level and the deeper penetration of tidal waters in deltas Develop a tilapia strain with high growth performance AND salinity tolerance! O.niloticus: high growth rate but no saline tolerance O.mossambicus: high salinity tolerance but low growth performances Development of the hybrid O. mossambicus x O. niloticus MOLOBICUS Genetic selection on growth performances De Verdal et al., 2013

17 Step 1: Hybridization Crossbreeding between O. niloticus males and O. mossambicus females (MoNi) and between O. mossambicus males and O. niloticus females (NiMo) And 2 generations of backcrossing (to increase the proportion of O. mossambicus genome) De Verdal et al., 2013

18 Long Term Salinity Test Step 1: Hybridization Mortality 80% 70% 60% 50% 40% 30% 20% 10% 0% H2 MoNi H2 NiMo H3 MoNi H3 NiMo O moss O nilo H2 generation showed a lower mortality than H3 and O. mossambicus O. niloticus showed the highest mortality De Verdal et al., 2013

19 Long Term SalinityTest Growth Comparison Step 1: Hybridization De Verdal et al., 2013

20 Selection impact on BW Difference between hybrid and control (in g) Generation y = 16,938x - 10,791 R² = 0,9777 y = 10,693x - 15,622 R² = 0,8896 Intensive Extensive A genetic gain of 17 g by generation in intensive system and of 10.7 g by generation in extensive system De Verdal et al., 2013

21 Search for salinity tolerance markers in the black-chinned tilapia Sarotherodon melanotheron Cellular Physiological Genomics Immunolocalisation CFTR Ouattara et al., 2009 Aquaculture Link et al., 2010 Mol. Cell. Endo. Tine et al., 2008 Mar. Genomics

22 Further studies should analyze: the temporal evolution of physiological and genetic adaptations to osmotic and thermal stress in aquatic animals. This could be one of the topics of common interest between Israelian research groups working on tilapia physiology and/or genetics and our group.