bs_bs_banner Animal Conservation. Print ISSN 1367-9430 Distribution patterns of Yangtze finless porpoises in the Yangtze River: implications for reserve management X. Zhao1,2,D.Wang1, S. T. Turvey3, B. Taylor4 & T. Akamatsu5,6 1 Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China 2 China Three Gorges Corporation, Beijing, China 3 Institute of Zoology, Zoological Society of London, Regent’s Park, London, UK 4 NOAA Fisheries, Southwest Fisheries Science Center, La Jolla, CA, USA 5 NRIFE, Fisheries Research Agency, Kamisu, Ibaraki, Japan 6 Japan Science and Technology Agency, CREST, Tokyo, Japan Keywords Abstract acoustic survey; encounter rate; finless porpoise; habitat preferences; line transect The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis)isa sampling; moving average; reserve design highly threatened cetacean endemic to the middle and lower reaches of the Yangtze River that has suffered a dramatic decline in recent decades. We charac- Correspondence terize and quantify recent distribution patterns of porpoises in the Yangtze River Ding Wang, Institute of Hydrobiology, in order to facilitate strategic management of existing in situ cetacean reserves and Chinese Academy of Sciences, Wuhan maximize effective utilization of limited conservation resources. We calculated 430072, China. Tel: +86 27 68780178; porpoise relative abundance (encounter rate) using a 1-km moving average along Fax: +86 27 68780123 the Yangtze main stem based on a combined visual and acoustic survey conducted Email: [email protected]; in 2006. We then evaluated conservation priority areas based on encounter rates [email protected] along the river. High-porpoise density areas (> 0.20 porpoises km-1) cover approximately one-third (33.9%, 599 km) of the survey area and contain approxi- Editor: Karina Acevedo-Whitehouse mately two-thirds of the porpoise population, making them priority areas for Associate Editor: Rob Williams porpoise conservation. In contrast, low-porpoise density areas (Յ 0.05 porpois- es km-1) cover 28.8% (509 km) of the survey area but contain only 4.5% of the Received 15 March 2012; accepted 6 porpoise population, and may already be of little value for porpoise conservation. December 2012 Five high-priority porpoise conservation sites and five sections that now contain few or no surviving porpoises are identified. Proposed spatial modifications to doi:10.1111/acv.12019 existing reserves and associated conservation recommendations are made for five existing protected areas along the Yangtze main stem, and we emphasize that some additional river sections should urgently be designated as new protected areas given their high porpoise density. Our approach for identifying conservation priorities may provide lessons for reserve design and management in other pro- tected area networks. Introduction number is almost certainly an underestimate because of failure to account fully for the porpoises missed during Population status of the Yangtze surveys (for details see Zhao et al., 2008). The population finless porpoise had declined to c.1200 animals in 2006, with an average rate of decline of at least 5% year-1 (Zhao et al., 2008). A 150-km The Yangtze finless porpoise (Neophocaena asiaeorientalis gap in porpoise distribution between Shishou and Yueyang asiaeorientalis) is an obligate freshwater subspecies of the was also identified in the 2006 range-wide survey (Fig. 1; narrow-ridged finless porpoise that is endemic to the middle Zhao et al., 2008). The main threats to the long-term sur- and lower reaches of the Yangtze River between Yichang vival of finless porpoises in the Yangtze are a range of and Shanghai and two appended lakes, Dongting Lake and anthropogenic activities, including incidental by-catch in Poyang Lake (Fig. 1; Gao & Zhou, 1995; Chen et al., 2010). fishing gear, electrofishing, collisions with heavy ship traffic, During the past three decades (1980s–2000s), the Yangtze pollution and water construction projects (Wang, Zhang & finless porpoise population has experienced rapid popula- Liu, 1998; Wang et al., 2005, 2006a,b; Wang, 2009; Turvey tion decline and fragmentation (Zhao et al., 2008; Wang, et al., 2013), which were also responsible for the decline and 2009). The estimated size of the finless porpoise population recent probable extinction of the sympatric Yangtze River in the main stem of the Yangtze River was approximately dolphin or baiji (Lipotes vexillifer; Turvey et al., 2007). The 2550 animals in the early 1990s (Zhang et al., 1993). This tragedy of the baiji emphasizes the severity of the situation Animal Conservation •• (2013) ••–•• © 2013 The Zoological Society of London 1 Porpoise distribution patterns and reserve management X. Zhao et al. Figure 1 Sketch map showing locations of cetacean reserves (pink numbers) and major cities, indicated by downstream dis- tance in km from Yichang along the Yangtze main stem. Light blue line shows current distribution of Yangtze finless porpoise. Table 1 Summary of cetacean reserves in the Yangtze main stem Reserves Upper limit index (km) Lower limit index (km) Position DD°MM′ Grade Year established Length (km) Shishou Xinchang Wumakou E 112°25′, N 29°57′ National 1992 89 214 303 E 112°51′, N 29°46′ Honghu Xintankou Luoshan E 113°16′, N 29°36′ National 1992 136 410 546 E 113°52′, N 30°13′ Anqing Sanhaozhou Zongyang E 116°22′, N 29°51′ Municipal 2007 223 919 1142 E 117°39′, N 30°46′ Tongling Zongyang Jinniudu E 117°39′, N 30°46′ National 1993 58 1122 1180 E 117°55′, N 31°05′ Zhenjiang – – E 119°24′, N 32°15′ Provincial 2006 15 1458 1473 E 119°32′, N 32°13′ Total – – – – 501 Boundaries of reserves are given as downstream distance (in km) from Yichang. Notes: (1) There is a c.20 km overlap between the area covered by Anqing reserve and Tongling reserve. For convenience of analysis, this overlap area was only counted in Tongling reserve, so that the range of Anqing reserve used in our analyses is 919–1122 km. (2) Lengths given for Shishou and Tongling reserves exclude their additional ex situ sections (see text for further details). now facing the Yangtze finless porpoise, and the need for Honghu (1992) and Tongling (initially established as a pro- urgent conservation action for this highly threatened ceta- vincial sanctuary in 1993 and upgraded to a national reserve cean. Indeed, the current status of the finless porpoise is not in 2006; Fig. 1). The Shishou reserve consists of a 21-km ex much better than the status of the baiji in the late 1970s and situ reserve (the Tian’e-Zhou oxbow) and an 89-km in situ early 1980s (Zhou et al., 1982), and environmental condi- protected area in the Yangtze main stem. Similarly, Ton- tions in the Yangtze River are continuing to deteriorate gling reserve consists of a 1.6-km ex situ reserve and a 58-km (Dudgeon, 2010). The Yangtze finless porpoise may now be in situ protected area. We will focus only on the in situ areas critically endangered according to the categories and criteria of both reserves in this study. These three protected areas of the IUCN Red List (Mei et al., 2012), and many conser- were established primarily for conservation of baiji, and vationists have been urging immediate actions to insure the were established in regions of perceived high baiji abun- long-term persistence of this cetacean (Wang et al., 1998, dance (see Turvey et al., 2010), but they are now considered 2006a; Guo, 2006; Zhao et al., 2008; Wang, 2009; Stone, to provide protection for finless porpoises. Two further in 2010). situ protected areas, established more recently in 2003 at Zhenjiang (a provincial reserve) and in 2007 at Anqing (a municipal reserve; Fig. 1), were primarily set up to conserve Cetacean reserves in the Yangtze River finless porpoises. Different levels of reserve status (national, Five in situ cetacean reserves have been established in the provincial and municipal) in China receive different levels of main stem of the Yangtze River since the 1990s under the financial support and public attention. National reserves approval of the Chinese authorities (Table 1; Fig. 1). Fol- receive the maximum level of funding and public attention, lowing the conservation recommendations proposed during and so can provide the most effective protection. the ‘Workshop on Biology and Conservation of Platanistoid The Yangtze River, the so-called ‘golden channel’ of Dolphins’ held in Wuhan in 1986 (Perrin et al., 1989), three China, is now an extremely busy waterway that acts as an national-level reserves were established at Shishou (1992), essential transport route supporting the country’s rapidly 2 Animal Conservation •• (2013) ••–•• © 2013 The Zoological Society of London X. Zhao et al. Porpoise distribution patterns and reserve management growing industry and economy (Wang et al., 2006a; Turvey achieve more efficient conservation management for the et al., 2007), and it is unfortunately unrealistic to expect that species. all threatening anthropogenic activities within the Yangtze We provide a quantitative analysis of finless porpoise system will be regulated or prohibited even in cetacean distribution and abundance across its known range in the reserves. However, within these reserves, riverside factory Yangtze River main stem based on data from a range- construction is restricted, water construction projects wide, line transect visual survey combined with a towed- (ports, dams, bridges sand dredging) are either prohibited array acoustic survey that we conducted simultaneously in or require strict environmental impact assessments, and 2006 (Akamatsu et al., 2008; Zhao et al., 2008). We then monitoring is conducted regularly by reserve administration use these data to evaluate and identify priority regions for agencies. Electrofishing and use of rolling hooks are illegal porpoise conservation across the middle-lower Yangtze, throughout the Yangtze River main stem, and more vigor- and to make new management recommendations for ous enforcement of these activities for cetacean conserva- Shishou, Honghu, Anqing, Tongling and Zhenjiang ceta- tion should be expected in reserves.