Seahorse (Hippocampus spp.) hotspots and habitat associations in Thailand

Transcription

1 Seahorse (Hippocampus spp.) hotspots and habitat associations in Thailand Tse-Lynn Loh, Lindsay Aylesworth, Sarah Foster & Chuck Knapp Shedd Aquarium & Project Seahorse

2 Funky Fish

3 Seahorses under threat Trade: Traditional medicine, curios, aquaria (live) ~6.1 million dried seahorses exported worldwide annually ( ) Bycatch: Almost all (>80%) dried seahorses from trawling

4 Seahorse status CITES Appendix II includes species not necessarily threatened with extinction, but in which trade must be controlled in order to avoid utilization incompatible with their survival 14 species in SE Asia IUCN Red List Vulnerable: 7 species Data Deficient: 7 species

5 Why Thailand? million seahorses exported annually ( )

6 Spatial surveys Where do seahorses live? Distribution of species Habitat preferences Seahorse abundance index Population size structure, sex ratio, juvenile-adult ratio Are there dense aggregations along coast? Conservation hotspots

7 Survey sites Mar-Apr 2013

8 Initial survey methodology Habitats: Coral reef, seagrass, mangrove, estuary/soft-bottom intertidal m 2 surveyed per site using belt transects (~3-10h for 2 persons) 50m

9 Overall Results Total 8 seahorses Total survey area: ~1.7 ha (4.3 acres) 4.6 seahorses per ha

10 Are seahorses rare in Thailand? Talked to DoF officers, researchers, fishers, boat drivers, dive shop staff DoF Trang/Satun No seahorses in Satun province Not that frequently found in bycatch years ago, many seahorses Trang crab fisher (bycatch) From 100s of seahorses in traps per day to 1 seahorse in 3 months Usually fishers catch 1-2 seahorses per month now

11 Seahorse surveys Round 2 Fixed area transects empty transects Random swims With distance estimate (effort) Index of abundance instead of population density Find seahorse hotspots first Population characteristics Species distribution Habitat preferences

12 Find some seahorses! Social media and blast Facebook, Twitter List-servs: coral-list, ECOLOG-L Contacting local dive centers, conservation groups, researchers Internet search- Flickr, blogs, etc Translated request to Thai, posted on Thai divers forum Visit local fishing communities, landing piers

13 Survey sites Sep-Oct 2013 April 2014

14 Informal interviews With help of translators, spoke to 35 people fishers, boat captains and crew, dive guides, villagers, DoF officers, NP staff, etc Examined dried seahorse collections Seahorse population trends Catch/sighting per unit effort Fishing grounds, gear types Seasonality Personal estimates of trends, e.g. % decline?

15 16 of 48 sites 56 seahorses 3 species

16 Survey summary Location No. of survey days No. of survey dives No. of sites No. of seahorses Koh Tao Thung Walen, Chumphon Tong Tom 1 Snorkel 2 0 Samaesan Koh Kood, Trat Pattaya Ao Por, Phuket Ao Nang, Krabi Khanom 2 Snorkel 2 0

17 Seahorse summary 3 species Hippocampus comes, H. kuda, H. spinosissimus H. comes: coral reefs; Andaman Phuket Ao Nang H. comes

18 Seahorse summary H. kuda: coral reefs, sand, mangrove; Andaman and Gulf Koh Tao Ao Nang Chumphon H. kuda

19 Seahorse summary H. spinosissimus: sand, silt, rubble, seagrass; Andaman and Gulf Pattaya Samaesan Koh Kood H. spinosissimus

20 Seahorse summary Dried specimens only- H. trimaculatus Trawled from 25-40m depth Gulf of Thailand H. trimaculatus

21 Other seahorse species H. mohnikei Gulf and Andaman (new record) 10 of 13 male seahorses pregnant, most in mating pairs From fisher interviews, likely to be present in other areas, did not observe in surveys

22 Perceptions of population decline Fishers used to discard seahorse bycatch, but now seahorses are worth money Gift shop at Fossil Beach, Ao Nang: very few souvenirs from seahorses because hard to find now Seahorse declines from 50-90%. Three persons (fishers) said no decline.

23 Conservation Issues Interviews from 4 coastal communities Bottom trawling <1km from shore- destroy shallow habitats Can find nets even in protected areas Boats may come from other provinces Not enough officer to arrest, need volunteers too Declines in other fish catches too Ban Laem Prathap: switch occupation to agriculture and tourism Koh Kood: catch small fish for animal feed

24 Seahorse hotspots seahorses/100m 2.8 seahorses/100m

25 Habitat parameters NO 2, NO 3, PO 4, ph, salinity No pattern with nmds Silt + pencil urchins, artificial reef, shallow & turbid coral reefs What else?

26 The human factor Reduced fishing pressure Hat Noppharathara National Park No trawling >10 years Ko Pai Thai Navy protected area

27 The human factor Alternative livelihoods? Ko Lan one of the most heavily visited islands off Pattaya Pattaya very high volume of tourist visitation buffer against fishing activity? Access to market

28 Next steps Detection probabilities Occupancy study + habitat associations Integrate info from fisher interviews Intermediate disturbances? Removal of seahorse predators, nutrients

29 Citizen Science Engaging local communities to support conservation activities iseahorse.org Sightings Workshops Recruit volunteers for seahorse monitoring PADI Seahorse Specialty Looking for dive instructors and course directors

30 Acknowledgements Lindsay Aylesworth, Project Seahorse Dept. of Fisheries (Thailand): Ratanawalee Phoonsawat, Praulai Nootmorn, Yooee Getpech Jaeb (Dr. Parichart Laksanawimol), Chandrakasem Rajabhat University Field assistants: Top, Tum, Arm, Aey, Jew, Zoë Hagberg, Freshy Phuket Marine Biological Centre, Kasetsart University, New Heaven, Kiwidiver, Dive Tribe