Potential impacts of Climate Change on Loliginid Squid: Biology, Ecology & Fisheries. Gretta Pecl & George Jackson

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1 Potential impacts of Climate Change on Loliginid Squid: Biology, Ecology & Fisheries Gretta Pecl & George Jackson

2 Cephalopod research Beyond O Dor

3 Squid & Climate Change. Increased ocean temperatures Faster growth Shorter life spans Will climate change be beneficial to inshore squid fisheries? Growth rates increase, pop s larger, turnover of populations more rapid? Population expansion at the expense of slower growing teleost competitors? Response of squid populations may be much more complex!!

4 Basis of Talk.. Pecl, G. T. & Jackson, G. D. (2004). The potential effects of climate change on southern calamary in Tasmanian waters: biology, ecology & fisheries. Short paper for WWF U.S. NewsID=51982 Being revised to : Pecl, G.T. & Jackson, G.D. The potential impacts of climate change on inshore loliginid squid: biology, ecology and fisheries.

5 Cephalopod Fisheries Oceanic Ommastrephids & inshore Loliginids Basis of major cephalopod fisheries (80%) Major fished loliginids: Loligo gahi L. opalescens L. pealei L. forbesi L. vulgaris L. reynaudi Biomass can be very high very important components of local and National economies!

6 Large population fluctuations due to environmental changes Loliginids & Environmental Change Is long-term sustainability possible in the event of large changes in environmental regimes (Agnew et al 2005)? Climate change could have a major impact Population size Need to assess potential impacts more thoroughly than just temperature increases squid growth rates. Time

7 Loliginid Life History Geared towards life in the fast lane efficient digestion, protein based metabolism continuous growth efficient use of oxygen low levels of antioxidative defense Size Short life-spans (~ 1yr or less) high growth rates fast metabolisms ravenous appetites Age

8 Better poised than many other species to adapt to changes, however, is our perception of how squid may respond to climate change too simplistic? Loliginid dynamics Recruitment highly variable & every year a new cohort Huge flexibility and plasticity in life history

9 Climate Change What are proposed changes? Temperature increases El Niño s and more extreme El Niño s Ocean acidity Changes in upwelling intensity, size and location change in productivity zones? Ecologists, physiologists & resource managers face challenge of predicting effects of climate change on species and communities

10 Impact of Climate Change on Loliginids Taking a bottom up approach to explore how climate change may impact on: Physiology & morphology of individuals Phenology of individuals & populations Distribution/density of species Changes in species interactions, communities, ecosystems & fisheries

11 Physiology and morphology of individuals Growth & body size Reproduction Energetics/ respiration/metabolism

12 Growth & body size - Hatchlings (1) temperature, embryo development time embryo development time, hatchling size Smaller hatchlings unless females compensate with larger (but fewer) eggs!

13 Growth & body size - Hatchlings (2) Size at hatching may affect growth and final size-at-age!! Growth exponential - small differences between individuals amplified through the lifespan Weight Growth at 6% per day at different hatchling sizes How you start the race important Initial research with octopus shows relationship between hatchling size and growth IS important - but complex (Leporati et al in review) Days Pecl et al (2004a) Mar FreshW Biol.

14 Growth & body size - Adults (3) Growth also linked to prey availability Faster life history but mature younger & smaller Growth rate depending on food x metabolism x temp relationship Some species will grow faster but not all temperature usually variance in growth rate (more in males in Loliginids) e.g. Sepioteuthis australis (Pecl et al 2004 b)

15 Loligo opalescens Jackson & Domeier (2003) Can act as ecosystem indicators Data collected over dramatic 97/ 98 El Niño/La Niña biggest climatic event of century temp productivity; temp productivity

16 Body size with time Mean mantle length (mm) A Males Females bcd ab ab a bcd bc cde bc ef def f ef Win 97,98 Sum 98 Aut 98 Win 98,99 Spr 99 Sum B f 70 Mean weight (g) a a abc ab bcd bc bcd bc de cde e Win 97,98 Sum 98 Aut 98 Win 98,99 Spr 99 Sum 99 Season of hatch

17 Upwelling index Upwelling index Mean age (days) Mean age (days) Jun 98 Dec 98 Jan 99 Feb 99 Mar 99 Apr 99 May 99 Jun 99 Jul 99 Aug 99 Sept 99 Oct 99 Nov 99 Dec 99 Jan 00 Feb 00 Mar Body size vs. age Males A B Males Weight (g) Mean mantle length (mm) Dec 97 Jan 98 Feb 98 Jun 98 Jul 98 Aug 98 Sep 98 Oct 98 Nov 98 Dec 98 Jan 99 Feb 99 Mar 99 Apr 99 May 99 Jun 99 Jul 99 Aug Body size vs upwelling index A mantle length upwelling index B Females -50 Month of hatch Mean mantle length (m) Mean mantle length (mm)

18 Californian study showed: Squid act as ecosystem indicators of environmental change Squid responded quickly to change Food was over-riding factor not Temp. El Niño/La Niña effects were dramatic Potential model of climate change

19 Reproduction (1) How do changes in growth rates and body size impact on reproduction? Cool conditions larger body & gonad = reproductive output Warm conditions smaller body size & although greater relative gonad investment, absolute gonad weight = reproductive output

20 Reproduction (2) Body weight (g) Gonad weight (g) Hot Cool Cool Hot Jackson & Moltschaniwskyj (2002) S. lessoniana

21 Warmer temperatures Shorter embryonic phase Smaller hatchlings Faster growth?? Earlier maturity Smaller adult size Lower reproductive output? Shorter lifespan

22 Energetics, respiration, metabolism (1) High metabolic rates in squid growth costs will dominate energy flux through an individual Feeding rate with temperature Cannibalism can allow for trophic flexibility so individuals still thrive temp time hatchlings can survive without food Hatchlings will need more food but have less time before facing mortality

23 Energetics, respiration, metabolism (2) O 2 consumption linearly with weight but metabolism continuously with temp At temp, smaller squids do better than larger CO 2, ocean ph, impair O 2 transport in squid may limit scope for activity (Seibel and Fabry 2003) Higher metabolism but less access to oxygen!!

24 Phenology of individuals & populations Advances in life cycle events (migrations, egg laying) Expect larger changes near poles than equator (Root et al 2003) Climate change will likely result in shorter life-spans Temporal synchronicity of spawning activities of temperate populations reduced? De-synchronisation of peak spawning & peak productivity may have implications for juvenile growth rate and survival

25 Distribution/density of species (1) Biomass Biomass may be affected by the carrying capacity of the changing ecosystem If productivity the rate of cannibalism within populations may however, biomass may be reduced if the level of cannibalism is high. Location of peak abundance and range shifts Climate change may influence population movements by altering temperature, quality and quantity of food, or in the case of benthic spawning squids, altering the characteristics of the seafloor habitat.

26 Distribution/density of species (2) Timing of peak abundance Cephalopod biomass production strongly cyclical and usually an annual phenomenon except in some small/tropical species What happens as life spans shorten as a function of temps? Pecl & Jackson 2004 Figure largely adapted from Boyle & Boletzky 1996

27 Distribution/density of species (3) General predictions include (Hughes 2000): Extension of species geographic range boundaries towards poles Extinction of local populations along range boundaries Increasing invasion of weedy and/or highly mobile species especially where local populations of other species are declining

28 Species interactions, Communities, Ecosystems & Fisheries Largely unknown & hard to predict in the absence of detailed & complex ecosystem models Progressive decoupling of species interactions due to mismatched phenology e.g. one species cued by day length (no change) and other by temperature Changing currents may affect larval dispersal and retention Many pathogens temperature sensitive warmer waters increase susceptibility?

29 Some Additional Considerations. Synergism of several pressures at once habitat destruction, over fishing etc in addition to climate change (Root et al 2003) Maybe no fisheries by 2048 (Worm et al. 2006) Climate change will effect species differently depending on habitat impact may depend on geographical region (eg. closed regions such as Mediterranean)

30 Impact Summary Smaller hatchlings - unless females compensate with larger (but fewer) eggs! Hatchlings will need more food but have less time to find food before facing mortality - recruitment variability? Higher metabolism but less access to oxygen!! Smaller body size, shorter faster lifespans, reduced reproductive output Squid will eat more and grow more rapidly than fish at comparable sizes and temperatures

31 Data & Research Needs.. Longer data series needed!!! Telemetry can be used to track movement Understanding trophic links critical How does smaller hatching size affect growth and final size-at-age? At higher temperatures: Do females produce larger eggs to compensate for smaller hatchlings (caused by shorter embryo durations at higher temps)? Do females spawn more frequently and/or for longer to compensate for smaller gonad weight? Impact of lowered ph & reduced O 2 availability?? VERY CRUCIAL!! What life history characteristics are cued by day length vs temperature?

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