S9: FIS/TCODE Topic Session Resilience, Transitions and Adaptation in Marine Ecosystems under a Changing Climate 2016 PICES Annual Meeting, San Diego, USA, Nov.9-10, 2016 Status and trend of four commercially important coastal cephalopods in China Seas: an overview with implications for climate change Yongjun Tian, Yumeng Pang, Yanli Tang, Yiping Ren and Rong Wan Fisheries College, Ocean University of China Qingdao, China; E-mail: yjtian@ouc.edu.cn
Outline 1. Backgrounds: Why cephalopod is hot? 2. Status of Chinese coastal cephalopod 3. Trends in four typical cephalopod 4. Summary and outlook
World cephalopod capture is increasing thousand ton 90000 80000 70000 60000 50000 40000 30000 20000 10000 Other species excluding cephalopods 0 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Cephalopods Year Marine Capture Production (fish, crustacean, mollusc) Data source from FAO (1950-2014) Cephalopods late 1980s regime shift 6000 5000 4000 3000 2000 1000 0
Global proliferation of cephalopods Cephalopods, including squid, cuttlefish and octopus From pelagic to demersal species Both fisheries data and survey data Global warming impact (Doubleday et al. 2016, Current Biology)
Under over-exploitation, why are cephalopods increasing? Adapt to changing Question: environment quickly: Cephalopod might take advantage of changing environment to expand Most population. studies (Doubleday focused et al. on 2016) oceanic Rapid growth, short lifespan and strong life-history flexibility: species Recruitment such as and flying spatial squids. distribution of oceanic cephalopod are easily affected by climate In China Seas, one of the most changes. (Sakurai et al. 2000) heavily over-exploited ecosystems Environmental factors such as sea temperature and food in availability the world, strongly what influence happened growth and in development of inshore squid. (Pecl et al. 2008) coastal cephalopods?
Data and method 1. Chinese fishery annual report (1979-2013) Logbook of fisheries company in Yantai (2014) annual catch of fish and cephalopod species 2. Japanese and Korean catch statistics (1950-2010) Sea around us (1950-2013) catch of Chinese oceanic cephalopod 3. Selection of four typical coastal cephalopods 4. STARS analysis regime shift detection developed by Rodionov (2004)
Variations of fish and cephalopod in China seas 12000 1200 thousand ton 10000 8000 6000 4000 Fish Cephalopod abnormal increase 1000 800 600 400 2000 200 0 1979 1984 1989 1994 1999 2004 2009 Year 0 (Data source: Chinese annual fishery reports)
thousand ton 1200 1000 800 600 400 200 0 Cephalopod composition in China Seas 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Japanese flying squid 1950-1978 1979-2011 No Chinese official statistics on cephalopods. Data from sea around us showed a peak during early 1960s for Japanese flying squid. Japanese flying squid Argentine shortfin squid Chinese annual fishery report Year Distant water fisheries for Jumbo and Japanese flying squid developed. The coastal squids are estimated excluding distant water species. Jumbo flying squid Statistic data from sea around us Chinese coastal squid
Four typical coastal cephalopods are selected. Partly overlapped distribution with contrastive life history. Overwintering ground Spawning ground Distribution golden cuttlefish Japanese loligo squid 15~23 13~16 common Chinese cuttlefish swordtip squid 18~26 21~24
Species Maximum size Environmental /climate range Ecology Spawning season Fishery golden cuttlefish Sepia esculenta 180mm/ 600g Demersal, Eurythermal species Spend winter in deep Long duration with water and return to latitudinal shallow water in spring difference, mostly to spawn. The eggs are between spring and laied onto substrates, early summer like seaweed. Coastal areas of Shandong and middle of Yellow Sea are good fishing grounds in spring and winter. Japanese loligo squid Loligo japonica 120mm/ 76g Pelagic (~10m) cold water species The fishery is concentrated in the front area of coastal currents and oceanic currents. Spawning migration starts in March and spawning starts in May Fishing season is from December to March next year. Fishing happens in north and middle of Yellow Sea. common Chinese cuttlefish Sepiella maindroni 200mm/ 800g Demersal (~50m) warm water species Be selective to spawning habitats. The eggs are laid onto egg masses or seaweed. Seasonal spawning, lasting from April to June off Japan and East China Sea Winter, spring and summer are mean seasons for fishery. Zhejiang coastal areas used to be fishing grounds swordtip squid Uroteuthis edulis 400mm/ 820g Pelagic (30-170m) warm water species Diurnal vertical migration. The longevity in temperate waters is around 1 year and in subtropical waters is 9 month. Spawn all year round, two distinct spawning seasons (spring and autumn) in East China sea. Fishing period ends in winter. Resources are exploited in Taiwan mainly.
Regime shifts in North Pacific Two regime shifts in large marine ecosystem of North Pacific in 1977 and 1989. ( Hare and Mantua 2000) Recent studies also suggested regime shift-like change occurred in the late 1990s in the northwestern North Pacific associated with ENSO (Tian et al. 2014)
Golden cuttlefish catch trend 70000 60000 50000 40000 Sea of Japan Korea 30000 20000 10000 0 1950 1960 1970 1980 1990 2000 2010 2020 Late 1980s regime shift
Japanese loligo squid catch trend 200000 Bohai Sea and Yellow Sea 160000 120000 80000 40000 regime shift Change in effort? 0 1955 1960 1965 1970 1975 1980 1985 1990 A regime shift occurred around mid-1970s Decrease since late 1980s associated with effort changes to high value filefishes.
Loligo squid still remains in a high level 12 11 10 9 8 Month 7 6 5 4 3 2 1 0% 20% 40% 60% 80% 100% Octopus ocellatus Loligo.spp Octopus variabilis (Data source: Coastal fisheries-dependent research in Shandong in 2014)
Trawler surveys in Haizhou Bay in 2011, 13 Dominated Octopus species in spring Abundant loligo squid in fall Appearance of golden cuttlefish only in fall
Common Chinese cuttlefish catch trend 50000 40000 30000 20000 10000 East China Sea Stock collapsed in the late 1980s with increasing WT and fishing pressure. 0 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Unfavorable environment: increasing water temprature Intensive fishing and destruction on habitat and spawning ground
Swordtip squid catch trend 30000 25000 Southern East China Sea Sea of Japan 20000 15000 10000 5000 0 1985 1990 1995 2000 2005 2010 2015 2020 Impacts of strong ENSO events?
Summary Both the catch and percentage of Chinese coastal cephalopods increased largely since 1990s in spite of the over-exploitation in China Seas. Four typical cephalopods showed decadal variation patterns and different response suggesting impacts of environmental changes addition to the heavy fishing. Intrinsic biological traits is one of the most important reasons for different responses to environmental changes. Climate changes such as regime shift and strong ENSO events should be paid particular attention to the Chinse coastal cephalopod in the context of ecosystem-based management.
Chinese coastal cephalopod outlook Fisheries-independent survey ecological roles in China Seas major species composition dominate species and related life strategies Fisheries-dependent research annual yield of major fishery species variation of catch composition
New Survey Started in Oct. 2016 New survey covered the coastal water of Shandong Province started in October, 2016. Previous surveys in Haizhou Bay indicate increasing cephalopods. 20
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